STATIC AND DYNAMIC CALIBRATION FOR COHERENCE IMAGE FORMATION MEASUREMENT SYSTEMS AND METHODS

Abstract

Systems and methods for static and dynamic calibration could be used to align a measurement beam from a coherence imaging (CI) measurement system with a processing beam from a material processing system. These systems and methods could generate a calibration measurement output from the CI measurement system and / or an auxiliary sensor. Subsequent measurements performed by the CI measurement system could be modified based, at least in part, on this calibration measurement output.

Description

STATIC AND DYNAMIC CALIBRATION FOR COHERENCE IMAGING MEASUREMENT SYSTEMS AND METHODS Cross reference to related requests The present application claims the benefit of United States Provisional Application Serial No. 63 / 011,235 filed on April 16, 2020, which is fully incorporated herein by reference. Technical field The present disclosure relates to coherence imaging measurement systems and methods for monitoring high energy beam processing applications and more particularly, relates to static and dynamic calibration techniques for alignment of a measurement beam. in coherence imaging measurement systems and methods. Background of the invention The use of coherence imaging (Cl) measurement systems (e.g., IPG Photonics LDD700 system) to monitor laser processing applications (e.g., laser welding, metal manufacturing laser addition, laser marking, laser material removal, laser cleaning, etc.) offers immense benefits to process results. The benefits of Cl systems are mainly realized in their spatial and temporal relationships in the laser process itself. For example, more specific relationships include the spatial-temporal relationship of the measurement beam Cl to the processing laser beam site on the workpiece undergoing processing. A typical single measurement of a Cl system, referred to herein as the A-line, is shared, significantly, depending on the context in which it is acquired. Significantly, this meaning is assigned in part based on where the measurement is taken: in space in relation to the workpiece (for example, subcomponent A and subcomponent B in a tool application training component). union AB); in space relative to the process cell (e.g., relative to a workpiece fixture, relative to a cell coordinate frame, relative to a tooling coordinate frame, etc.), in the space relative to the process (e.g., ahead of the process path vector); in time relative to the process (e.g., 100 ms, once the process is completed); in space relative to the processing laser focal site (e.g., 0.1 mm behind the processing beam); in time relative to the processing laser energy modulation (e.g., 0.5 ms after each laser pulse in a series of laser pulses); and in time relative to a processing laser beam modulation pattern (e.g., 0.05 ms after the onset phase of a circular laser oscillation pattern). In the laser welding example, the Cl measurements could be taken at a specific distance far enough in front of the processing laser focal site, during laser processing, so that the measurements are not affected by the process itself. , although close enough to the focal site, that precise measurements of the part fit geometry (for example, the seam line between the two components that are being joined by the welding process) could be used to determine whether the location or Focal site is sufficiently aligned with the seam or joint line. In some cases, these measurements could be additionally used to dynamically correct misalignment. Similarly, Cl measurements made in the phase change region during laser welding could be used to measure the keyhole depth of the welding process, a critical metric for many laser welding processes. For many laser processing applications, the recording of Cl measurements with the laser focal site and temporal energy modulation profile must be of sufficient accuracy and precision for the resulting measurement to be useful in the context of process monitoring. and process control. Specific requirements may vary depending on the application and the types of Cl measurements being performed by the application. For example, in multi-mode laser welding applications, it is often sufficient to spatially record Cl measurements with the process beam, at the surface of the workpiece, to within distances on the order of tens to hundreds of microns. . While in single-mode laser welding applications, registration distances on the order of a few tens of microns to single microns might be desirable. Similarly, time recording in the temporal energy profile of the processing laser on the order of tens of microseconds is sometimes desired for keyhole depth measurements of pulsed welding applications. This recording may be desirable to ensure that Cl measurements are made while the keyhole vapor channel is open. The above examples help illustrate the importance of spatial temporal registration of the Cl system with the processing laser in a few laser processing applications. However, the general importance extends beyond the limited examples provided above. This recording is beneficial in altering the behavior of the measurement system to acquire more useful measurements, as well as determining the usefulness of a measurement (for example, by quantifying its lack of recording) and consequently, by altering data processing. measurement. In some applications, strict registration requirements involve a trained professional to commission the Cl system on site at the laser processing station. In some applications, it may be necessary for Commission procedures to be performed, iteratively, until the specific requirement is met. In these cases, the registration requirements imposed by the application are very time intensive. Minimal knowledge and time to perform these procedures can be a large barrier to future modifications to the laser processing station since this may involve redeployment of a trained professional, large amounts of remote support from a trained professional, or a significant amount of front-end training for laser processing station operators. In many applications, the registration procedure and Cl system calibrations are specific to the hardware configuration (for example, specific to the laser processing station) and need to be performed for each Cl deployed system. Design and manufacturing tolerances may involve calibrations being performed for each laser processing station even if the stations are nominally the same. Similarly, in some applications, additional calibration procedures are desired to perform recording procedures that are specific not only to the laser processing station, but are specific to the process itself. As a result, Cl systems that are used to monitor a variety of laser processing applications, or even different types of the same laser processing application, could involve many calibrations. In cases where the Cl system has some resonant component, oscillating properties or other characteristics where the phase of the A-line acquisition timing cycle is difficult to control and / or predict, the temporal-spatial relationship between the A-line and the rest of the process may sometimes need to be determined, retrospectively. However, even in these cases, the techniques and devices described herein provide benefits of equivalent value when compared to implementations where A-lines could be activated “on demand.” Manufacturing tolerances, in combination with very strict registration requirements, could involve recalibration of the Cl system after common, although relatively infrequent, laser processing station procedures. These procedures could include: changing the sliding protective cover of the laser head; changing the focal length of the laser head focusing optical device; replacement of laser supply fiber; replacing the laser head with a spare; and adjustment of the Cl system optical delivery device. In these applications, end users of the Cl system may be required to monitor the system log throughout its use or may be required to perform multiple calibrations throughout its entire life cycle. operational. External environmental effects (e.g., temperature changes, vibrations, humidity) and maintenance (replacement of process fibers, cleaning of systems) can vary the registration between the process and the optical forming device of image. Because these influences cannot always be isolated to a subset of system components, a means of directly recording together the various imaging and energy beam systems, taking into account the net effect of all these influences on the joint registration. In many cases, the best way to accomplish this is to use the imaging system(s) to make an observation of the interaction of the process beam with a material. Consequently, there is a need for a new apparatus and method that: improves the accuracy of recording procedures; improve the accuracy of registration procedures; reduce the time requirements of registration procedures; automate (semi or fully) registration procedures; alleviate the minimum knowledge and experience requirements to carry out registration procedures; or some combination of these. Brief description of the invention Consistent with an aspect of the present disclosure, a system includes a material processing system, a coherence imaging (Cl) measurement system, and one or more controllers. The material processing system includes a processing beam source for generating a processing beam and a processing beam head for delivering the processing beam to a target. The coherence imaging (Cl) measurement system includes a coherence imaging (Cl) core unit for generating a measurement beam and a Cl scanning module for delivering the measurement beam to the target, where The measurement system Cl produces a measurement output Cl. One or more of the controllers are configured to receive the measurement output Cl from the core unit Cl to monitor and / or control the material processing system. One or more of the controllers are also configured to receive the measurement output Cl from the core unit Cl to monitor and / or control the material processing system. The controllers are also configured to receive a calibration measurement output and to control the Cl measurement system as a function, at least in part, of the calibration measurement output such that the controllers are configured to control the Cl measurement system. to modify future measurements made by the Cl measurement system for alignment of the Cl measurement system and the processing beam. Consistent with another aspect of the present disclosure, a method is provided for calibrating a coherence (Cl) imaging measurement system. The method includes: providing a material processing system configured to generate and deliver a processing beam to a target; providing a coherence imaging (Cl) measurement system configured to generate and deliver a measurement beam to the target and configured to supply a measurement system output Cl to control and / or monitor the material processing system; obtaining a calibration measurement output from the measurement system Cl and / or from an auxiliary sensor; and automatically controlling the measurement system Cl based, at least in part, on the calibration measurement output, wherein the measurement system Cl is controlled to modify future measurements made by the measurement system Cl to the alignment of the Cl measurement system and the processing beam. Modifying future measurements made by the Cl measurement system could include performing system level calibrations, performing process level corrections, and / or performing intra-process level corrections. In some embodiments of this method, the Cl measurement system is automatically controlled to modify future measurements made by the Cl measurement system so that static calibrations are performed for alignment of the Cl measurement system and the processing beam. In other embodiments of this method, the Cl measurement system is automatically controlled to modify future measurements made by the Cl measurement system so that dynamic calibrations are performed for alignment of the Cl measurement system and the processing beam. Consistent with a further aspect of the present disclosure, a system includes a material processing system, at least one material processing system controller, a coherence imaging (Cl) measurement system, and at least one system Cl. The material processing system includes a laser for generating a laser processing beam and a processing beam head for delivering the laser processing beam to a target. The laser is configured to output substantially a single spatial mode with an M-square value less than 2.0. The material processing system controllers are configured to cause the material processing system to generate and direct the laser processing beam to the target for a calibration measurement. In some embodiments of this system, the material processing system controller could be configured to cause the material processing system to generate and direct the laser processing beam to the target to produce a physical modification to the target. In these embodiments, the calibration measurement output could be a function of the physical modification and the system controller Cl could be configured to control the measurement system Cl to align the measurement system Cl relative to the physical modification. In other embodiments, the material processing system controller could be configured to cause the material processing system to generate and direct the laser processing beam to the target to generate localized process radiation at the target. In these embodiments, the calibration measurement output could be a function of the localized process radiation and the system controller Cl could be configured to control the measurement system Cl to align the measurement system Cl relative to the localized process radiation. . The Cl measurement system includes a coherence (Cl) imaging core unit for generating a measurement beam and a Cl scanning module for delivering the measurement beam to the target, where the Cl measurement system produces an output The Cl system controllers are configured to receive the Cl measurement output from the Cl core unit to monitor and / or control the material processing system. The Cl system controllers are also configured to receive a calibration measurement output and to control the Cl measurement system based, at least in part, on the calibration measurement output. The Cl system controllers are configured to control the Cl measurement system to modify future measurements made by the Cl measurement system for alignment of the Cl measurement system and the processing beam. In some embodiments of this system, the measurement system Cl could include an online coherence imaging (ICI) measurement system and the measurement system Cl could be configured to produce the calibration measurement output. In other embodiments, an auxiliary sensor could be configured to produce the calibration measurement output. Consistent with yet another aspect of the present disclosure, a method is provided for calibrating a coherence (Cl) imaging measurement system. The method includes: providing a material processing system that includes a laser configured to generate and deliver a laser processing beam to a target; providing a coherence imaging (Cl) measurement system configured to generate and deliver a measurement beam to the target and configured to supply a measurement system output Cl to control and / or monitor the material processing system; generating and directing the laser processing beam to the target for a calibration measurement; obtaining a calibration measurement output from the measurement system Cl and / or from an auxiliary sensor; and automatically controlling the measurement system Cl based, at least in part, on the calibration measurement output, wherein the measurement system Cl is controlled to modify future measurements made by the measurement system Cl to the alignment of the Cl measurement system and the processing beam. In some embodiments of this method, the laser could be configured to output substantially a single spatial mode with an M-square value less than 2.0. In some embodiments of this method, the laser processing beam produces a physical modification to the target, which corresponds to a position of the processing beam. In these embodiments, the calibration measurement output could be a function of the physical modification and the measurement system Cl could be controlled to align the measurement system Cl relative to the physical modification. Obtaining the calibration measurement output could include, for example, measuring the physical modification with the Cl measurement system. In other embodiments, the laser processing beam generates localized process radiation at the target, which represents a position of the processing beam. In these embodiments, the calibration measurement output could be a function of the process localized radiation and the Cl measurement system could be controlled to align the Cl measurement system relative to the process localized radiation. Obtaining calibration measurement output could include, for example, detecting localized process radiation with the CL measurement system Brief description of the drawings These and other features and advantages will be better understood by reading the following detailed description, taken together with the drawings, where: A schematic block diagram of a laser processing system and a coherence imaging (Cl) system capable of performing Cl system calibration measurements is shown in Figure 1, consistent with embodiments of the present disclosure. A schematic block diagram of a laser processing system and a coherence imaging (Cl) system with a 2D in-line camera for Cl system calibration measurements, consistent with other imaging modalities, is shown in Figure 2. this disclosure. A schematic block diagram of a laser processing system and a coherence (Cl) imaging system with a double-coated fiber and photodetector for Cl system calibration measurements, consistent with modalities, is shown in Figure 3. additions to this disclosure. A schematic block diagram of a laser processing system and a coherence imaging (Cl) system with a 2D camera below the laser head for Cl system calibration measurements is shown in Figure 4. consistent even with additional embodiments of the present disclosure. A series of images is shown in Figure 5 illustrating an example process beam recording calibration performed using interferometry output measurements acquired during a raster scan of a marked calibration target and processed using a series of calibration algorithms. image processing. A block diagram illustrating examples of interferometry measurement data processing algorithms employed by process beam recording calibration is shown in Figure 6. A schematic illustration of example Cl system scan module measurement acquisition scan patterns used for future detection in Cl system calibration measurements is shown in Figure 7. A graph illustrating an example of timing gating strategies used to distinguish between back-reflected process beam light and process radiation emanating from the laser interaction zone is shown in Figure 8. Graphs illustrating an example process radiation line scan performed with the system shown in Figure 1 at two positions within a laser scanning head scan field are shown in Figure 9. A schematic illustration of an example of process beam recording using an apparatus with a 2D in-line camera is shown in Figure 10. A schematic illustration of a shared optical pathway between the Cl system scanning module and the online camera is shown in Figure 11. A graph illustrating an example temporal gating scheme used to distinguish process beam variable and imaging beam variable measurements using the 2D camera in the system of Figure 2 is shown in Figure 12. . A schematic illustration of calibrations to align the Cl system reference frame with the workpiece / process beam reference frame is shown in Figure 13. Figure 14 shows graphs illustrating an example of the process radiation measurements recorded by the system shown in Figure 1 (left) and data processing operations such as noise rejection and noise adjustment. curve, which could be used to find the data centroid (right). A schematic illustration is shown in Figure 15 highlighting an example of the difference in the commanded imaging beam position and the current measurement beam position with correct and incorrect tracking errors when scanning in opposite directions. Graphs illustrating example signal measurements obtained while scanning through a static setup in two opposite directions using a correct tracking error (top) and a bad tracking error (bottom) are shown in Figure 16. . A schematic illustration of an example of the types of corrections that need to be applied to imaging system scan module positioning commands, as a function of scan field position to correct distortions, is shown in Figure 17. optics in a laser scanning head. A schematic illustration of an example of path-specific imaging beam measurements and process beam registration for an apparatus involving a laser scanning head is shown in Figure 18. An image is shown in Figure 19 illustrating the calibration measurements performed by the system of Figure 3, which employs a double-coated fiber in combination with an auxiliary photodiode, used to determine the location of the process beam center ( 1) and the trajectory direction (2) during a laser process. An image is shown in Figure 20 illustrating the calibration measurements made by the system of Figure 2, which employs a 2D in-line camera, used to determine the location of the process beam center and path direction during a laser process. Figure 21 shows images and graphs illustrating example calibration measurement techniques performed by a system using point-based measurement acquisitions (for example, a single-point process radiation or interferometry output measurement in combination with the OI system scan module) to identify the process direction. A schematic illustration of an example of how changes to the keyhole laser welding process, such as changes in process speed, could cause the location of the vapor channel to change relative to the focal position of the process beam. Figure 23 shows schematic illustrations of how the use of measurement lines transverse to the nominal laser processing path direction can be used to identify the difference between the nominal and actual processing paths. A schematic illustration of a local surface tilt calibration measurement process is shown in Figure 24. An image illustrating an area of ​​a workpiece captured by a Cl system scan and including a laser site diameter identified using imaging data collected by the Cl system is shown in Figure 25. Detailed description Systems and methods for static and dynamic calibration, consistent with the present disclosure, could be used to provide alignment of a measurement beam of a coherence imaging (Cl) measurement system (also referred to as a Cl system). in relation to a processing beam of a material processing system. Calibrations could be performed t / ΓΑοη / ζζηζ / Σΐ / γίΛΐ on the system before the process is performed (i.e., system level calibrations), during a process (i.e., process level calibrations), and / or between processes (i.e., intra-process level calibrations). Although laser processing systems are shown in the illustrated embodiments, the systems and methods described herein could be used with any type of high energy beam processing applications (e.g., an electron beam) and are not only laser processing. Embodiments of Cl measurement systems include, for example, an in-line coherence imaging (ICI) system, such as those described in US Patent Nos. 8,822,875, 9. 757,817 and 10,124,410, United States Patent Application Publication No. 2020 / 0023461 and United States Patent Application Serial No. 16 / 721,306 (now U.S. Pat. App. Pub. . No. 2020 / 0198050), all of which are fully incorporated herein by reference. With reference to Figures 1-4, systems 100, 100', 100", 100"', consistent with embodiments of the present disclosure, generally include a material processing system, a formation measurement system coherence image (Cl) and controllers / processors to control both systems. The material processing system includes at least one material processing beam source (e.g., laser 110) that delivers a processing beam 111a to a workpiece 102 by an energy beam delivery system (e.g., the laser head 112) to perform a material modification process. The measurement system Cl includes a core unit Cl 120 that provides a measurement beam 121 to the workpiece 102 and produces an interferometry output of at least one component of the measurement beam 121 directed at and reflected from the workpiece 102. One or more of the controllers / processors (e.g., laser controller 154 and Cl controller 156) could be used as a feedback controller that monitors at least one processing parameter of the material modification process and a feedback controller. which adjusts the behavior of the coherence imaging system based on at least one calibration measurement. The coherence imaging system (i.e., the Cl core unit 120) comprises an imaging optical source (not shown) that produces the imaging light (i.e., the measurement beam 121). and an optical interferometer (not shown) that produces an interferometry output that uses at least a component of the imaging light that is supplied to the workpiece 102. The coherence imaging system also includes a module scanning beam 122 that directs at least one component of the imaging light relative to the material processing beam source (e.g., laser 110). The Cl 156 controller could include a processing unit that performs data processing and analysis at the interferometry output and a controller that coordinates measurement acquisition, directs the position of the scanning module, and communicates with external elements. The controller Cl 156 could act as a feedback controller that uses at least one of the interferometry output measurements to calibrate the behavior of the imaging system by means of its measurement acquisition and the t / ΓΑοη / ζζηζ / Σΐ / γίΛΐ positioning of the scanning module. In some embodiments, measurements used to calibrate the performance of the imaging system are obtained, additionally or alternatively, by means of one or more auxiliary sensors or detectors. The workpiece 102 undergoing material processing could be a component or subcomponent with specific functionality, or it could be a calibration target whose purpose is to enable a coherence imaging system calibration measurement. The material processing beam source could be a laser 110 or electron beam source. The laser beam 111 could be a single mode beam or a multimode beam. A single-mode beam includes a beam with an M-square value of 2 or less and more specifically, 1.5 or less. The laser beam source 110 could include, without limitation, a fiber laser, a disk laser, a solid state laser, a diode laser, or a CO2 laser. The laser beam 111 could have spectral components in the ultraviolet region, the visible region, or the infrared region. In the case of a laser beam, the energy beam delivery system (e.g., laser head 112) could include one or more of a fixed optical device head, an oscillating head, a target scanning head pre, or a post target scan head. The laser head 112 could include an instrumentation port to interface with the coherence imaging system and to introduce the measurement beam 121 substantially in a coaxial direction with the laser beam 111. Where auxiliary sensors are included in the system , laser head 110 could include additional instrumentation ports, such as an in-line camera port (see, for example, Figure 2). Additional auxiliary sensors could include online cameras (e.g., 2D online camera 230 in Figure 2), photodiodes (e.g., photodetector 330 in Figure 3), and spectrometers. Auxiliary sensors could also have their own sensor control modules to analyze and process measurements. The outputs of the auxiliary sensors are fed back to the Cl 156 controller and are used for calibration of the coherence imaging system. The material modification process performed utilizing the systems described herein may include, without limitation, one or more of the following: welding; boring; court; address; drilling; brass soldering; sintered; surface treatment; additive manufacturing; and subtractive manufacturing. An example of oscillation deducing processing monitoring and control using ICI is described in greater detail in United States Patent Application Publication No. 2020 / 0023461, which is fully incorporated herein by reference. The apparatus could also include other processing equipment, such as motion control stages (e.g., motion stage 104), robotic arms, processing atmosphere systems, pneumatic knives, shielding gas, and process controllers. The Cl measurement system could be one of, or could be a variant of, the most common Cl measurement system variants, including: time domain optical coherence tomography (TD-OCT); Fourier domain optical coherence tomography (FD-OCT), spectral domain optical coherence tomography (SD-OCT); swept source optical coherence tomography 1 (SS-OCT); low coherence interferometry (LCI); and coherent online image formation (ICI). In SD-OCT and its variants, a low-coherence light source produces light in a finite spectral band, for example, 830-850 nm. This light is injected into an interferometer and finally measured using a spectrometer, which could include a grating and a line-scanning camera. Examples of light sources used in SD-OCT type systems include superluminescent diodes (SLDs) and frequency combs. In SS-OCT and its variants, a tunable narrow-band light source produces narrow-band light that is injected into an interferometer. The injected wavelength of light center is tuned with respect to a spectral band to produce a single interferometry output. In general, light is measured by a photodiode or a balanced photodetector that is synchronized with the spectral sweep of the light source. Examples of light sources used in SS-OCT include Fourier domain mode locked (FDML) sources and vertical cavity surface emission lasers (VCSELs). Generally, variants of the Cl measurement system share the following features: a beam splitter (e.g., a 50:50 fiber evanescent mode coupler) that splits light from the light source into a sample arm, which supplies light from the imaging beam to the workpiece being measured and a reference arm, which contains the interferometer reference optical path and which could be static or adjustable. Light reflected back from the sample and reference arms is recombined in the beam splitter and transmitted to the detector of the imaging system. Cl measurement systems also include a signal processor to interpret the measurements coming from the detector. In the systems described herein, a beam scanning module 122 (e.g., a galvanometer scanner) is used to dynamically control the position of the measurement beam 121 (part of the path of the arm of sample) relative to the processing beam 111. The Cl controller 156 may apply system calibrations to influence the way the imaging or measurement beam 121 is positioned relative to the processing beam 111, when measurements are made. , and / or the way the measurements are processed and analyzed. The scanning module Cl could include any type of device and / or optical device capable of moving or deflecting one or more measurement beams including, without limitation, a galvanometer scanner, one or more moving lenses, a piezo scanner, a MEMS scanner, a KTN scanner, electrical-optical diverters (EOD) and acousto-optic diverters (AOD). The systems further include a feedback controller or processor (e.g., Cl 156 controller) that makes use of the coherent measurements to make determinations about process quality. The determinations could be a Boolean OK / NOK determination or could involve more complex process analyses. The feedback controller or processor could also make use of measurement data to adjust process parameters to improve future aspects of the process or future processes. The system could also include controllers for each of the main subsystems (e.g., a laser controller 154, a laser head controller 152, and a motion stage controller 158). The laser source 110 could have its own controller 154 to control the output power profile, timings, monitoring laser health, and to communicate with other submodules or a process master. The motion control equipment and process helps the subsystems to have their own controller 158 to control operations and communicate with other equipment. The laser head 112 could also have its own controller 152 to monitor the health of the laser head, to move the optical-mechanical components, and to communicate with other equipment. A Master process controller 150 (e.g., a programmable logic controller) could be used to control and coordinate all of the various subsystems and their controllers. In some cases, one of the subsystem controllers (e.g., laser head controller 152) could take the role of the process master. Modalities of contrast systems and mechanisms According to various embodiments, different contrast systems and mechanisms could be used as an input to provide calibration measurements to a feedback controller. As used herein, the term “contrast mechanism” refers to the physical property and / or measurement principle thereof that allows one or more aspects of the workpiece and / or the phase change region to be distinguished. each other. The modalities of these contrast systems and mechanisms are described below. System 100 using coherence imaging contrast mechanism According to some embodiments, the system 100 shown in Figure 1 could use the interferometry output measurements to provide the calibration measurements to the feedback controller (e.g., the Cl controller 156). In this embodiment, system 100 could still incorporate auxiliary sensors, although their measurements are not used as measurement system calibration inputs Cl. In this system 100, the measurement system hardware responsible for producing the interferometry output measurements of the laser processes is the same as the system used to generate the calibration measurements of the coherence imaging system. In most cases, this hardware maintains a similar configuration when performing calibration measurements as it does when performing process measurements. In some calibrations, however, it may be desirable to modify the hardware configuration, behavior and / or parameters for the purpose of improving the quality of the calibration measurement signal. For example, in an SD-OCT type scheme, the detector integration time could be increased to improve SNR when looking at specific calibration characteristics. In the general setting of interferometry, the reference optical path could be modified to better match the optical path length associated with the calibration workpiece. Similarly, the energy level of the imaging optical source could similarly be modified to produce back-reflected imaging beam levels more favorable for measurement of the calibration target. An example calibration measurement routine, a process beam registration, enabled by an embodiment of system 100 that uses a coherence imaging contrast mechanism is described below. Recording of system Cl in relation to process beam 111 is achieved by analyzing system Cl measurements taken when system scan module Cl 122 is directed at specific positions within the scan module reference frame. These reference charts could include: mechanical mirror deflection angles in the case of a galvanometer base scanning module; analog excitation voltage signal levels in the case of analog galvanometers; digital excitation voltage signal levels in the case of digital galvanometers; piezo excitation voltages; and a standard scan module reference frame that may or may not be head-independent. The precise position of the process beam 111 within the reference frame is unknown and is the goal of the calibration routine, although mechanical alignment of the optical-mechanical components generally ensures that the process beam 111 falls within the reference frame. scan field of the scan module. In this system, process beam registration is achieved by analyzing coherent measurements of a workpiece 102 that has undergone a localized physical modification as a result of the process beam 111. The physical modification in the workpiece 102 is used as a variable for the place or site of the process beam. Because all beam delivery elements in the system are used to make this mark and supply / collect the imaging beam 121, virtually all aberrant effects that would influence the ability of the Cl measurement system to remain accurate and precisely recorded in conjunction with the process beam 111 can be measured and compensated at the same time. A typical example of this contrast mechanism involves marking a small location on the workpiece 102 with the process beam 111, such that the location or location differs in height and / or reflectivity when compared to the unprocessed material. . The optical path or path length change aspect (i.e., height) of the coherent measurement could be used to provide the baseline path-length contrast to identify the site or location in the material. The back-reflected intensity aspect of the coherent measurement could be used to provide the reflectivity-based (and to some degree geometry-based) contrast to identify the site or material location. A combination of the height and intensity base contrast mechanisms could also be used to identify the location of the process beam. By making coherent measurements of the process-induced site at multiple points within the scan module reference frame, signal processing and statistical algorithms could be used to identify a region within the scan module reference frame as the center of the process beam (variable). For example, the processed site could form a small cavity in the workpiece 102. Base measurements of cavity height could exhibit behavior where the surface height decreases from the unmodified surface of material toward the center of the cavity ( a variable for the location of the process beam center). In a simple implementation, this location could be identified by taking the position (within the scan module box) of the coherent measurement that has the lowest measured height. In more complex implementations, image processing algorithms or placement operations could be deployed to identify a centroid region. In addition to identifying a centroid, the systems described herein could be used to determine boundary regions, centers of mass, centers of energy, or other definitions for the location of a process beam. A similar procedure could be performed instead of using backscatter intensity levels rather than measured heights. In other methods, a combination (e.g., intensity-weighted height measurements, height-weighted intensity measurements, etc.) of the two measurements could be used as the signal for processing. As shown in the overview of a site processing algorithm illustrated in Figure 5, process beam registration calibration could be performed using output measurements acquired during a raster scan of a marked calibration target. and processed using a series of image processing algorithms. A more detailed example of interferometry measurement data processing algorithms that could be used for process beam registration calibration is illustrated in Figure 6. In addition to variations in the signal types that can be used to identify the process beam variable, different scanning module search strategies could be deployed for the purpose of increasing the speed of the acquisition process, improving detection accuracy, simplify data processing or some combination thereof. Scan strategies (within the scan module reference frame) could include a 2D mesh pattern across variable, orthogonal scan vectors with a process beam center location updated, iteratively (e.g. a process similar to “beam walking” to achieve determination of the centroid for a Gaussian profile by fitting two octagonal axes), spiral scan patterns, discrete point measurements, feedback base random walk scanning, etc. . As illustrated by the scan pattern examples in Figure 7, different scan modulus measurement acquisition scan patterns could be used for configuration detection in Cl system calibration measurements that include a formation of square grid, cross pattern and spiral pattern. Averaging of detector measurements at the same position Cl of the scanning module could be performed to improve SNR and ruler variations due to non-ideal process. Similarly, differential measurements could be used to improve SNR and to reduce the influence of the characteristic dotted pattern common in Cl images. In this context, a differential measurement could include measuring a material surface before it is modified and after it is measured once again with substantially similar acquisition parameters once it is modified by the process beam. The two images are then compared with one or more differential calculations that are known to those of ordinary skill in the art. System 100 using a native process emission contrast mechanism In accordance with other embodiments, the system 100 shown in Figure 1 could use native process emissions as a contrast mechanism. In these embodiments, the Cl measurement system hardware may be configured, operated, or extended such that the optics and detector components of the Cl system may detect process radiation originating from the laser processing application. In this embodiment, system 100 could still incorporate auxiliary sensors, although their measurements are not used as measurement system calibration inputs Cl. In some implementations, the use of native process emissions involves an imaging light source that can be turned off or reduced to sufficiently lower the energy so that it does not interfere with the detection of the process radiation and an imaging system detector. image formation that can be operated, so that it can detect process radiation at levels above background noise. In particular, Cl spectral domain systems are well suited for this task because they can conveniently restrict their detection of process radiation to the wavelength bands used for the subsequent imaging task. coherence. This reduces and / or eliminates registration errors, resulting from chromatic aberration. In more specific implementations of system 100, the Cl measurement system could be extended to accommodate light transmission outside the spectral band of the Cl source to facilitate detection of process radiation by components of the Cl system. In still other implementations specifics, the Cl measurement system could also be extended to include a component to control the amount and / or color of light entering the detection system. This component could include one or more of the following: wavelength-specific filters; neutral density filtering with adjustable filter levels; changing the filter bending radius; The attenuator is fiber; and aperture adjustment (through the iris). Any of these elements could be removed and / or introduced, flexibly, into the optical pathway or path by means of actuators known to those of ordinary skill in the art. In some implementations, the return of process light through the optical path of the imaging system could be diverted to a secondary detector (e.g., a photodetector) better suited for these measurements or the Cl detector could be modified, specifically, to allow better detection of the calibration signal. An example calibration measurement routine, a process beam recording, enabled by an embodiment of system 100 that uses a native process emission contrast mechanism is described in greater detail below. The location of the process beam in the field of view is achieved by turning off, or reducing to an imperceptible level, the light source of the Cl system. The optical supply path of the Cl measurement system is used to transmit the process radiation emanating from the laser interaction zone, through the laser head and over the detector of the measurement system Cl. The optical supply path Cl could be temporarily modified (e.g. change in the filter or optical aperture) and / or the detector Cl could have its settings temporarily changed (for example, an increase in the integration time in the line scan camera in an SD-OCT type system) for the purpose of increasing the signal-to-noise ratio (SNR) of the measurement. of process radiation (e.g. blackbody radiation). In SS-OCT systems employing a balanced photodiode detection scheme, for example, one of the inputs to the channel pairs could be disabled (e.g., locked) to prevent common mode cancellation of the calibration signal. A specific laser process could be performed for the purpose of generating a localized process radiation source (e.g., a blackbody emitter) that will be used as a variable for the center of the process beam. Specific types of workpiece / test piece material could be used to enhance the signal of the variable at the detector. Tungsten could be used to allow an increase in the energy density of the processing beam and resist surface melting. Other materials (types and geometries) could be used to specifically optimize the specific spectrum of blackbody radiation. Specific laser processing parameters (e.g., low energy versus high energy pulses) could also be used to improve the variable signal or to prevent damage to the workpiece. A damage-free laser process allows process radiation to be generated for variable detection while preserving the underlying part, making it possible to perform registration procedures directly on production parts and directly within the production environment. Additional auxiliary laser process considerations could be used to further improve workpiece resistance to damage and / or improve measured process radiation signals. Shielding gas deployed across the workpiece surface during laser processing could help stabilize surface temperature, mitigate workpiece oxidation, and keep detected signal levels consistent. A pneumatic knife could be used to prevent process vapors from obscuring the optical path to the detector, adversely affecting the SNR. In some cases, such as a scanner-based laser processing, where chromatic aberration could cause problems for accurate process beam registration, the optical supply path Cl could be intentionally or unintentionally modified, permanently or temporarily, in the process. production or during the calibration procedure, to improve the rejection of spectral bands outside the source band CL Transmission only of the spectral components of the process radiation that overlap with the light source Cl are for the purpose of identification of the variable can mitigate any type of registration errors associated with chromatic aberrations of the laser head. In other cases, where systematic errors associated with chromatic aberration might be imperceptible or non-existent, the Cl optical delivery path could be modified to transmit a broader spectral band to improve the signal collected from the process radiation. In some cases, the Cl optical delivery path could be modified to target a specific spectral band or bands of the process radiation. Targeting specific spectral bands helps improve recording accuracy since certain spectral bands may be more strongly associated with the variable while other spectral bands may be by-products of the environment or process used to create the variable. For example, a laser pulse could be used to establish a laser interaction zone on a steel plate to act as a blackbody emission source (the variable), where the peak of the spatial blackbody emission profile coincides with the center of the processing beam. The primary spectral components associated with the variable fall primarily in the infrared part of the spectrum. Plasma could be produced as an unintended byproduct of the laser process, which in turn could increase the levels of process radiation in the visible and ultraviolet spectral regions. Due to the process environment and process equipment (e.g. shielding / shroud gas flow), the spatial location associated with the peak plasma radiation signal could differ from the spatial location associated with the center of the source. of blackbody emission and could cause errors in determining the location of the center of the variable. By rejecting spectral components outside the infrared region, signals associated with the plasma could be rejected and the center of the blackbody emission source could be detected with improved precision. Similarly, a notch filter could be employed in the optical path of the Cl system to block back-reflected process beam light for better targeting of blackbody radiation. In some embodiments, it may not be feasible to filter the process beam radiation with an optical component. In this case, the temporal gate could be used to separate the process radiation in the laser interaction zone from the back-reflected process beam light. An example of this temporal gating includes a pulse-based laser processing waveform where process radiation measurements are only made (or saved) during the off portion of the pulse duty cycle. As shown in the temporal signal gating example in Figure 8, temporal gating strategies could be used to distinguish between back-reflected process beam light and process radiation emanating from the laser interaction zone. Knowing the laser energy profile (the solid line) allows detector signal measurements (the dashed line) taken only when the laser is off to be isolated. If the laser energy profile is not known, specific features of the detector signal, such as the back-region (the target signal), can be used to isolate the detector signal associated with the desired process event. This type of gate ensures that only the radiation generated at the surface of the workpiece is collected by the measurement system. Similar temporal gating techniques could be used to effectively filter out unwanted spectral components that might have longer or shorter decay times. In some implementations, precise temporal gating could be achieved through access to (or command of) the laser gating drive signal. In some cases, however, it may not be feasible or accurate to perform temporary gating by this method. As a result, features of the acquired signal itself could be used to perform temporal gating. As an example, the identification of a large spike followed by a tail region could be used to isolate the desired spectral components in the form of a signal tail (see Figure 8). In other implementations, an additional photodiode could be used to optically identify the laser in periods by measuring the back-reflected process beam light. In another example, where the imaging and processing beam wavelengths are close enough that chromatic aberration produces imperceptible error or where the optical delivery system has been constructed such that chromatic aberration is not problem, the back-reflected process beam light could itself be used as a variable for detection. In this example, the laser process could be selected so that the laser intensity is too low to produce any significant heating of the workpiece or absorption of the processing beam. Instead, light from the processing beam is reflected back off the workpiece and part of it is transmitted through the OI optical supply path and onto the detector. In this example, the peak spatial intensity of the back-reflected light is used as the variable for the process beam center. Similar scan module scanning strategies and signal processing strategies to those described above (e.g., see Figure 7) could be applied to acquire and analyze the process detected radiation signal. The measured process radiation for points along a linear scan through the laser interaction zone is shown in Figure 9. Process radiation measurements made at two positions within a Laser scanning head scanning field using scanning along the system scanning Cl. Similar measurements can be made to determine the alignment along the Y axis. As shown in Figure 9, in the center of the scanning field of the laser head, the alignment of the reference frame Cl with the process beam is good. As a result, the scan intensity profile is maximized at a distance of 0 pm along the scan performed in the reference frame Cl. Due to chromatic aberration, at the center point in the scan field of the head laser (top right), the same measurement scan performed on the reference frame Cl presents a peak intensity profile signal at -200 pm along the scan. Future positioning operations of the measurement beam Cl can then take this error into account to improve positioning accuracy. Similar registration measurements can be made at other locations within the process beam scan field and along other axes of the Cl reference frame to improve overall calibration. Iterative scanning techniques similar to “beam walking” could be applied to improve measurement accuracy. Averaging the detector measurements at the same position Cl of the scanning module could be performed to improve SNR and rule variations due to process non-identities. 100' system with 2D online camera The system 100' shown in Figure 2 further includes a 2D in-line camera 230, for example, coupled with a 2D camera port included in the energy beam delivery system. In some embodiments, the Cl controller 156 could include at least one processing unit for extracting and analyzing the 2D camera measurements and the data acquired by the 2D camera measurements could be transferred to the feedback controller responsible for implementing calibration of the Cl system. In most implementations, the Cl system hardware allows the imaging light source to be turned off or reduced to a sufficiently low power so that it does not interfere with the detection of process radiation. Alternatively or additionally, the imaging light source could be temporally modified so that, for at least one instance in time, it does not interfere with the detection of the process radiation. In many implementations, 2D camera measurements are extracted by one camera controller and passed to another controller responsible for performing data processing operations. However, in some cases, the camera controller may assume this responsibility. Data processing could be done by another dedicated piece of hardware or it could be done on existing hardware, such as the feedback controller. The 2D camera port included in the energy beam delivery system (e.g., laser head 122) could be used in an in-line camera configuration (e.g., looking through the beam delivery system). In other implementations, the 2D camera could be set or positioned off-axis to avoid sharing the optical paths of the processing beam and the imaging beam. In an off-axis configuration, multiple 2D cameras could be used to achieve multiple viewing angles during the calibration measurement. In any configuration, the optical path of the 2D camera could also include additional optical devices (e.g., focusing lenses, filters, apertures, mirrors) to improve the quality of the calibration measurement. The optical path could also be designed to better transmit certain spectral bands (e.g., NIR) and specifically to reject others (e.g., VIS). The specific optical path of the 2D camera 230 in relation to the processing and measurement beams 111, 121 could be variable. In some embodiments, the camera port could share at least some component of the optical path with the measurement beam 121. In others, there is no overlap in the optical path. The 2D camera hardware may also have adjustable properties (e.g., exposure time, frame rate, field of view) that can be configured according to the type of calibration measurement being performed. An example calibration measurement routine, a process beam recording, enabled by an embodiment of the system 100' with a 2D in-line camera 230 is described in greater detail below. Process beam registration is achieved by performing imaging beam registration to the online camera reference frame (e.g., camera frame pixels) and processing beam registration to the same image frame. online camera reference. When both beams, or more specifically, their individual beam variables, are recorded in the camera reference frame, the separation distance within the camera frame could be used to quantify the degree of registration of the imaging beam and the processing beam (or, conversely, its degree of misalignment). An example of variable registration of the processing beam and the imaging beam using the 2D camera is shown in Figure 10. The 2D inline camera detects back-reflected imaging beam light (the imaging beam variable) and process radiation (the process beam variable). Image processing is used to identify the degree of misalignment and accordingly corrects the position of the imaging beam. The image in Figure 10 shows the misalignment of the imaging beam variable and the processing beam variable. For the purpose of registering the imaging beam variable to the processing beam variable, the position of the processing beam variable could be registered to the 2D camera. The Cl system scanning module is used to actively adjust the position of the imaging beam until its position variable overlaps (to within an acceptable degree) the processing beam variable. In the case that specific calibration of the imaging beam position in the 2D camera frame has been performed a priori, so that the locations of the imaging beam variable in the camera are mapped to the positions of the scanning module Cl, registration of the imaging beam into the processing beam could be performed by backward calculation of the offset correction between the imaging and processing beam variables in the camera. In this type of setup, adjustments to the optical paths and the 2D camera allow detection of both the imaging and processing beam variables. A processing beam variable could be set similarly to that described above for system 100 using the native process emission contrast mechanism. An imaging beam variable could be established using at least some component of the imaging beam light reflected back from the workpiece surface. Similar to what was described for the optimization of workpiece material and geometry for system 100 using the native process emission contrast mechanism, the workpiece material and geometry could be selected to deflect a specific amount of the imaging beam reflected back toward the 2D camera. In the case where the optical path of the camera and the optical path of the Cl system are shared, as shown in Figure 11, deflection of some part of the beam reflected back from the Cl system towards the camera could be achieved by a splitter. beam. Depending on the specification and requirements of the Cl system detector and camera, the splitter ratio (for example, 50:50 vs 90:10 vs 99:1) could be device specific. Light splitting could also be achieved using a Cl polarized light source and a polarizing beam splitter. Other possible means of directing light from the imaging beam reflected onto the camera include a mechanically adjustable reflector (e.g., a mirror) to direct the light toward the measurement system Cl when coherent measurements are desired and to direct the light towards the camera when beam registration processing is desired. In the case where the optical path of the camera is separated from the optical path of the Cl system (for example, an off-axis camera), the type of geometry and / or material and / or the fixation position of the workpiece They could be intentionally selected to induce diffuse scattering or pointed angled specular reflections by increasing the amount of light directed along the camera's optical path. The fact that both the imaging beam variable and the processing beam variable are recorded in the 2D camera presents some additional challenges to individual detection. As registration of the imaging beam into the processing beam improves, the two variables begin to overlap in the camera and could not be distinguished, individually. If chromatic aberration is not significant and the processing beam variable is composed of different spectral components than the imaging beam variable then adjustable spectral filtering could be applied to resolve each beam variable in the detector. However, if chromatic aberration is not noticeable, or a simpler implementation is favored, the two sites could be temporarily resolved. An example of a 2D camera temporal gating scheme used to distinguish process beam variable and imaging beam variable measurements using the 2D camera is shown in Figure 12. As shown, temporal modulation of the laser energy (solid line in top graph) and imaging beam energy (dashed line in top graph) and synchronization with the 2D camera frames allows frames are classified as process beam variable frames (lower left graph) and imaging beam variable frames (lower right graph). For example, the processing beam variable could first be detected in the camera by turning off or blocking the light source Cl. Laser processes similar to those described for system 100 that use a native process emission contrast mechanism could be used to generate the processing beam variable in the detector. Once the processing beam variable has been identified in the camera frame, its Center Pixel location is stored and laser processing is stopped. The light source Cl is then turned on. The imaging beam light reflected back from the workpiece provides the imaging beam variable in the camera. The center pixel of the imaging beam variable could then be recorded and compared to the center of the process beam variable to determine the degree of registration. This information could then be fed back to the Cl system (as described above) to further improve calibration. Depending on the frame rate of the 2D camera, the rise / fall time of the processing beam, the rise / fall time of the light source Cl and the workpiece, the two variables could also be temporarily resolved when performing a pulsed laser processing sequence. While a multi-pulse sequence is not strictly necessary to co-register the two beam variables, frame averaging is not permitted to be performed to improve the SNR associated with the central identification of each variable and a measurement is permitted. more precise. Frame averaging could be used to combat noise resulting from a variety of sources including camera shot noise, laser process non-idealities, workpiece surface imperfections, low levels of signal, poor camera contrast, etc. In addition to temporal gating of processing and imaging beam variable signals, system settings may also need to be modified specifically for processing beam variable acquisitions. the imaging beam variable, or for both. Due to the different nature of each radiation source, it is likely that the radiation intensity levels could be different when looking at each variable. As a result, it may be necessary that techniques such as dynamic optical filtering adjustment camera exposure times, processing energy adjustment, or imaging beam energy adjustment be applied to ensure that the optical intensity levels of each variable are within the measurable range of the detector. 100” system with double coated fiber The system 100" shown in Figure 3 further includes a double cladding fiber 330 used to transmit light from the coherent imaging system within its core and to transmit process radiation within its cladding. In this system 100", at least the photodetector 332 is used to measure the process radiation of the coating of the double coating fiber and the data processing hardware (for example, the Cl controller 156) is used to extract the measurements of the photodetector. Details of this configuration are described in US Patent No. 10,124,410, which is fully incorporated herein by reference. In most implementations of system 100", the system light source Cl can be controlled, so that it can be adjusted to facilitate, or not interfere with, system calibration measurements. An example calibration measurement routine, process beam recording, activated by system 100 is similar to that described above for system 100 using a native process emission contrast mechanism. In this example, the process beam variable is measured by collecting the process radiation, transmitting it through the inner coating of the double-coated fiber, and recording it on a photodetector. Unlike system 100 which uses a native process emission contrast mechanism, the process radiation collected by the Cl system detector is not used for calibration measurements. Photodetector measurements are synchronized with the position of the Cl system scanning module to map the measurements to the useful Cl system reference frame. Chromatic differences between the coherent measurement beam spectral band and the spectral components collected by the inner coating could lead to chromatic aberrations when attempting to co-register the imaging system reference frame with the process radiation. To account for these errors, chromatic aberration effects could be corrected by data processing (for example, calibrated ahead of time, i.e. modeled) or negated by optical filtering of the spectral components of the process radiation. that are sufficiently far from the spectral band of the measurement beam. 100”’ system with 2D camera positioned below The system 100"' shown in Figure 4 further includes a 2D camera 430 positioned sufficiently close to the process work plane (i.e., the plane containing the surface of the workpiece). The system 100"' also includes optical filtering elements (not shown) to control the amount and spectral components of light reaching or reaching the 2D camera and at least one processing unit (e.g., controller Cl 156). ) to extract and analyze 2D camera measurements. The data acquired by the 2D camera measurements could be transferred to the feedback controller responsible for implementing CL system calibration An example calibration measurement routine, process beam registration, activated by system 100'" is similar to that described above for system 100' that includes the 2D inline camera. In this case, however, the 2D camera 430 is positioned on the work plane and is directly used to detect the image processing and forming beams. Generally, the 2D camera 430 also has additional filtering to ensure that the imaging and processing beams are sufficiently attenuated to levels that can be measured by the detector. The system 100'" could also include additional controllers and automatic hardware to allow automatic positioning of the 2D camera 430 in the correct calibration measurement positions while a calibration is being performed and to position the 2D camera 430 so that it is out of the way when laser processing has been done. In other systems, positioning of the 2D camera 430 could be done manually by the system operator. Techniques similar to those described for system 100' could be used to synchronize measurements and beam positions in camera 430 to allow each type of beam to be distinguished. In many cases, additional synchronization of the power levels of the processing source and the imaging light source is desirable to achieve readings in the range of the detector (i.e., above the detector noise and below its saturated value). In some cases, it may not be possible to reduce the power of the processing source to a low enough level that it could be measured by the detector. To accommodate this, some systems might make use of the source pump exhaust light instead of the operating beam. In other systems, additional optical beam sampling components could be used to reduce the intensity of the processing beam before it reaches the detector. Some systems may include an additional calibration light source with similar spectral qualities to the processing source, albeit at substantially lower output powers, which can be directed substantially along the optical path of the processing beam. Calibration luminous current could be used as a variable for the process beam source for 2D camera measurements. While the energy levels of the imaging light source can generally be reduced low enough to be detected, the same techniques could also be applied to the imaging beam. In additional embodiments, a combination of any of the above systems 100, 100', 100", 100"' could be useful to achieve or achieve different detection contrast mechanisms since different techniques could be better suited for certain types of recording procedures and laser processes. Calibration types Various types of calibrations could be performed using the systems described above to benefit different types of laser processing applications. The examples described herein are non-limiting examples that are commonly found in laser welding applications. While these examples are described in the context of laser welding, these examples and recording processes could be extended to other forms of energy beam welding and other laser processing applications. Generally, calibration measurements can be performed by the system in the absence of a priori inputs to the calibration process. In some cases, however, a priori information could be useful to reduce calibration time and to increase calibration accuracy. The a priori information could be in the form of one or more of the following: a default calibration, compiled from a series of past calibration measurements of the same type on similar subsystems; past calibration measurements for the same subsystem; and outputs from optical models or simulations such as those used by computer optical simulation software, such as Zemax Optical Design. For some applications, a priori information could be used to achieve sufficient calibration, although in most applications, a priori information is used to supplement the measurement system calibration routine. Static calibration The above systems could be used to perform static (i.e., process-specific) calibration measurements. Typically, these measurements are performed when a Cl measurement system is first integrated into a laser processing station or when modifications are made to the Cl optical delivery device and / or the process beam optical delivery device. For applications with high precision calibration requirements (e.g., single-mode laser processing), these calibrations could be performed more frequently to compensate for equipment tolerance limitations, temperature change, environmental fluctuations, mechanical vibrations. , dynamic forces during processing, etc. By communicating with the process master and / or external equipment, one or more of these static calibrations can be performed in the context of using the system in series production. One or more static calibration procedures could also be performed on workpieces that are being processed by the system periodically, after a certain threshold of failed quality measurements, after changes in temperature, after maintenance, or after one or more parts of the processing system are replaced. Because the space available on the workpieces could have geometric complexity in the vicinity of the calibration marks, some embodiments include the ability to suppress part of the scanned image data so that these regions do not falsely attract and confuse contrast detection algorithms. In cases where multiple calibration procedures are performed, these results can be averaged and their distributions analyzed to determine whether the registration of the process and measurement beams is likely to be correct. For example, if the width of the measurement distribution is equal to or larger than the expected size of the process beam in the workpiece then registration is likely to be poor. However, if the distribution of measurements is much smaller than this value, then the chances of a good record are high. The following examples are first described in the context of calibration. Additional subexamples are used to illustrate how the contrast systems / mechanisms described above could be deployed to perform this calibration. Although only a few selected subexamples are described herein, the contrast mechanisms and systems described above could be used in other subexamples that are not explicitly described herein. Specific calibrations could be achieved using the contrast system modalities and mechanisms described above. Process beam / workpiece reference frame registration In CL system integration with laser heads, process beam alignment / registration provides a significant origin for the CL system scan module reference frame Hardware origin (the origin of the electrical / mechanical reference frame ) of the imaging system scanning module does not naturally coincide with the process beam center without calibration or alignment. In this way, a process beam center registration measurement is advantageous to align the origin of the imaging system scanning module with the process beam center. As illustrated by the alignment of the imaging system reference frame shown in Figure 13, calibrations could be used to align the system reference frame Cl (the imaging system frame) with the frame process beam / workpiece reference frame (head reference frame). Measuring the process beam center in the XY imaging system scanning module frame provides XY correction for the imaging system to center its reference frame around the origin of the process beam. Similar calibrations could be used to align the orientation of the XY imaging system scanning module with the orientation of the XY workpiece / head and provide a scale calibration that matches the scales of the imaging system scanning module. XY image with XY workpiece / head scales. Detection of the process beam center could be achieved through one or more of the contrast variables and mechanisms described above (e.g., process radiation, workpiece surface demarcation, and beam detection). back based on the length of the optical path, the demarcation of the workpiece surface and the back intensity of the back reflected beam, etc.). Subsequent detection of the process beam center could be performed with one or more of the sensors described above. The following examples illustrate possible implementations of the process beam center alignment procedure, although many other variations are possible. In one implementation, the process beam is used to mark a small configuration on a workpiece positioned overhead. The configuration is marked small enough to locate its centroid to within an acceptable tolerance (e.g., ±10-20 pm), yet large enough to produce a distortion on the surface of the part (e.g., warpage in height, the change in surface reflectivity, the change in polarization, etc.) that can be detected by the coherent measurement system. A distortion in which the maximum or minimum distortion coincides with the center of the process beam is generally desirable, for example, a laser ablation process where the resulting hole has a maximum depth that coincides with the center of the process beam. Other laser markings and / or site welds may also be used. Materials for this calibration include anodized aluminum, aluminum, steel, stainless steel, copper, Miquel-clad copper, and other commonly available metals. Polymers and graphite could also be used. In particular, graphite is advantageous because it does not have a liquid phase at regular atmospheric pressures. This means that the boundary of the laser mark is likely to be clearly defined and easy to segment with image processing algorithms. In one embodiment, the material that is marked is the product being manufactured in the cell, which allows for a new live calibration and / or verification of the overall registration of the beam in production. The imaging system scanning module moves the imaging site on the workpiece in a defined scanning pattern and the desired measurement amount (e.g., depth, intensity, etc.) is recorded. at each location. The process beam center is identified as the imaging site position, within the scan module reference frame, with the target signal value (e.g., a local maximum or minimum). Additional data processing techniques, such as fitting, averaging, and filtering, could also be employed to improve detection accuracy. A specific implementation of this process involves two calibration target measurement acquisitions, one before laser site processing and one after laser processing. The prefire acquisition is obtained from an unprocessed calibration target, or an unprocessed region of a calibration target. Afterfire acquisition is acquired after performing laser processing to create a configuration or feature on the target. This process could be a marking type process or an ablative type process. Example laser processing parameters include: a 3 ms, 600 W pulse generated with a continuous wave single mode laser; and a 2 ms, 2000 W pulse with a continuous wave multimode laser. The material types of calibration targets are described above. Each acquisition is a 4D data set that represents back-reflected intensity as a function of 3D position in space and is obtained by making coherent measurements while scanning the imaging beam through a mesh pattern. rectangular. The absolute difference between acquisitions is calculated. A series of image processing operations (e.g., intensity thresholding, contour calculation, and convex hull calculation) are then performed to increase the contrast of the image and to detect pattern points. A hierarchical filtering scheme, where each subsequent stage has fewer data points than the previous one, is used to clean the data. This scheme is divided into the stages of preprocessing, configuration point extraction and geometric adjustment. The preprocessing stage uses nearest neighbor denoising and image intensity thresholding techniques to extract the largest and most visible intensity cluster in the acquired data. The configuration point extraction stage depends on the cluster approximation and convex hull calculation for the purpose of calculating the configuration points in the extracted intensity cluster from the previous stage. The geometric fitting stage fits the circle at the extracted configuration points, a binding box and a minimum enclosed circle are calculated for the configuration points extracted in the previous stage. The outputs of the geometric fit are used to determine the location of the process beam variable and to evaluate the accuracy of the algorithm. The fit centroid is assigned as the location of the process beam variable. The fit radius is used to determine the accuracy of the fit by comparison to an expected range of values ​​governed by process parameters and processing beam site size. Different scanning pattern and search optimization strategies could be performed to improve the detection speed and accuracy, as shown in Figure 7. Simple scanning patterns include rectangular gratings, circular gratings, spiral gratings, raster scanning rectangular, spiral scan and cross scan patterns. More complex search could involve an iterative procedure with progressively finer search positions, more complex search strategies including random walking, the use of a priori measurements, and the use of models. Inputs to the calibration routine could include, for example, optical modeling of the nominal paths of the process beam and the imaging beam through the laser head, a collection of previous calibration point values, and / or a collection of similar calibration point values. These inputs could be used to provide a starting point around which the previously outlined calibration scan patterns are centered. A more precise starting center point could involve fewer measurement iterations to achieve the same level of calibration accuracy. A more concrete example involves the use of computational optical models to produce an imaging beam correction vector, to align the imaging beam with the processing beam near the workpiece surface, for configuration nominal optics. A series of correction vectors could be generated for different optical configurations, such as scanning mirror angles on a laser scanning head or different defocus positions. The correction vector is used by the measurement system during its calibration routine to center a rectangular mesh scan pattern around the corrected nominal position (i.e., produced from the computational optical model). This increases the probability that the calibration variable will be located within the scan measurement field of the calibration measurement, alleviating the need for search routines and iterative measurements for the same system calibration. In another implementation, the process beam is used to create a source of blackbody radiation at the surface of the workpiece by heating. The radiation source is most commonly a blackbody emitter, although in some implementations it could be a plasma generated by the process. Through careful selection of process parameters, it is possible to create a radiation source at the surface of the material without causing significant damage to the material itself. This process could be beneficial for target reuse, detection accuracy, and could even allow production parts to be used for the process. Using production parts as the calibration target could allow for reduced downtime on high-throughput production lines and could allow for more frequent recalibrations. Because the blackbody source is primarily mediated by energy absorption and conduction into the material volume, its apparent location must be extremely stable and symmetrical about the center of the process beam. This can provide a very accurate and repeatable recording of the beams. The radiation produced by the source could be captured, as described above, directly using the optical device of the coherent measurement system (for example, the system 100 shown in Figure 1), using the coating of a coating fiber. dual in combination with a photodiode (e.g., system 100' shown in Figure 3), a 2D in-line camera (e.g., system 100' shown in Figure 2), or some combination of the themselves. In the case of direct detection of the coherent measurement system or detection of the double-coated fiber, the measurement site is moved in a scanning pattern, as described above, and the detected intensity is recorded at each position. The scan position associated with the maximum intensity (or a similar prominent configuration, e.g., the center of mass of the signal) is identified as the origin of the process beam. Spectral filtering could be applied to the process radiation before detection to improve accuracy. An example of process radiation measurements recorded directly by the coherent measurement system during a linear scan along one of the axes of the imaging system scanning module is shown in Figure 14. In the setting of Example process radiation linear scan shown in Figure 14 illustrates process radiation measurements recorded by system 100 (left graph) and data processing operations (right graph). The graph on the left shows radiation intensity measurements as a function of the measurement position of the imaging system along its search axis. The right graph shows the result of additional data processing and fitting algorithms, such as noise rejection and curve fitting, to find the centroid. In this case, the adjustment centroid is representative of the position of the process beam center along the scan axis of system Cl. Here, the distance scale of the scan axis has been adjusted, so that the position of zero corresponds to the center of the fit to illustrate a corrected position of the Cl beam. In the case of the 2D online camera, the process radiation is recorded in the camera. The back-reflected imaging beam could be recorded at the same time or later in the camera (see Figure 10). The possible sequence of this detection is described in more detail above. If the in-line camera has already been calibrated in the imaging system, then the imaging beam position correction could be used to directly calculate the corrections in the imaging beam scanning module. However, if this calibration has not been performed, additional acquisitions of the back-reflected imaging beam could be performed at different positions of the imaging beam (which is directed by the scanning module) until the position error of the imaging beam (relative to the center of the process beam in the camera) has been sufficiently minimized. Additional data processing and spectral filtering could also be applied to improve performance. In many implementations, the position of the process beam center is detected, automatically, or with minimal user input, and saved as a general system calibration. Similar techniques could be used to identify and calibrate the scale and rotation of the Cl system, relative to a more convenient reference frame such as the laser head frame, the workpiece frame, or a world frame. While scaling and rotation are the primary corrective transformations used by a Cl system, additional transformations, such as reflections and distortion corrections, may be desirable to improve the positioning accuracy of the measurement system. Aspects of these calibration measurements could allow the same calibration process to be used to identify multiple transformation corrections for the Cl system. However, these transformation type calibration measurements could also be performed, independently. Generally, transformation calibrations are more involved than a process beam source type calibration due to the geometric nature of the problem. Often these involve creating more than one configuration on the workpiece (or below the laser head), such as a mark or radiation emitter on a calibration target / workpiece. For the purpose of determining the scale factor, for example, two features of a known separation distance are created in the reference frame in which the system Cl will be aligned. These configurations or features are identified in the system reference frame Cl and the separation distance between the configurations in the Cl frame is determined. The ratio of the distance of the reference frame Cl to the distance of the target reference frame is used to determine the corrective scaling factor of the CL system The same identified features could be used to determine the desired rotational correction for the Cl system. If the features or configurations are marked, with reference to a known axis or set of axes in the target reference frame, then the locations of the configuration relative to to a specific axis in the Cl system reference frame can be used to calculate the rotation to align the two reference frames. For these types of calibration processes, synchronization with the laser source and / or cell (e.g., through standard communication protocols or indirectly by a cell operator) could be advantageous. The above procedures could be extended to include more complex configuration generation to account for distortions and reflections of the reference frame, for example by creating configurations with distinct asymmetry around multiple axes in the reference frame. aim. In some configurations of the optical path of the Cl system, multiple transformation correction factors of similar type (e.g., multiple scaling factors) could be used to take into account: the multiple axes (not necessarily orthogonal) in the reference frame of Cl system; the multiple axes (not necessarily orthogonal) in the target reference frame; optical distortion in the path of the Cl system beam (e.g., optical distortions associated with the Cl scanning module); optical distortion in the beam path of the laser head (for example, lens distortions in a scanning head); the different geometries in the target reference frame (e.g., cylindrical versus spherical versus flat surfaces); and CL scan module trace error The Cl system scanning module is used to position and scan the imaging beam relative to the target reference frame. Scanning is enabled by optical devices, which are subject to inertial and finite acceleration constraints and / or limited pace. As a result, the true position of the imaging beam is delayed behind the commanded position by a tracking error. In a simple form, tracking error manifests itself as a constant time delay (e.g., 0.1 ms) of the imaging beam position behind the commanded position. Often the trace error follows a more complex system response and often depends on input drive commands themselves. The examples presented here illustrate the simplest form of tracking error, although the techniques outlined could be extended to identify and correct more complex patterns of tracking error. By creating a configuration or configurations, in the target reference frame (for example, a height mark or process radiation emitter) and commanding the Cl system scan module to scan through the configuration in different directions and along different axes, the tracking error could be determined. Figure 15 illustrates the difference in positioning in the target reference frame when tracking error is taken into account correctly versus incorrectly. In particular, the tracking error diagram shown in Figure 15 highlights the difference in the commanded imaging beam position and the current measurement beam position with correct and incorrect tracking errors when scanning in opposite directions. In the case of mistracking error we highlight how the distance between a static configuration measured while scanning in one direction versus the other can be used to calculate the mistracking error distance. When properly calibrated, scans across locations in the target reference frame produce the same measurement signal independent of scan direction. When incorrectly calibrated, the current position sampled in the target reference frame is systematically off or displaced relative to the commanded position in the same reference frame. Although the example in Figure 15 shows the delay of the true position behind the commanded position, it is possible that the true position could lead to the commanded position for certain types of mistracking errors. With the right type of imaging and targeting system scan pattern, an incorrect tracking error can be identified in the measurement of the target reference frame characteristic or configuration of the imaging system (or auxiliary system), which shown in Figure 16. In particular, Figure 16 shows example signal measurements obtained while scanning through a static setup in two opposite directions using a correct tracking error (top) and a Incorrect tracking (bottom). As shown, scanning in one direction produces a peak signal, such as that associated with the peak emission intensity of a process radiation emitter, at a position / time in the Cl system scan path, while Scans the same pattern through the same configuration in the opposite direction, producing a peak at a different position / time on the Cl system scan path. The difference in time / position on the scan path is used to determine the tracking error. In some cases, this difference is used in combination with additional knowledge or modeling of the scan module or other Cl system calibrations to determine the tracking error. As identified above, it is possible that the tracking error is dependent on aspects of the drive commands. Examples of these dependencies could include command speed, command offset, and scan module axis. To improve the accuracy of the Cl system, multiple tracking error calibrations could be performed according to different input conditions. Similarly, for the purpose of adequately acquiring tracking error calibration measurements, the Cl system, and in some cases its auxiliary sensors, could be modified (relative to its measurement operating conditions) to collect tracking error measurement signals. calibration. For example, the integration time of the Cl system detector could be extended or additional measurement averaging could be performed to achieve a better SNR of the process radiation emitter. Special laser processes could also be implemented to generate these signals. Just performing the tracking error calibration of the Cl scan module during production of the Cl system may be sufficient. However, tracking error calibrations could be performed in the end-use application for improved measurement accuracy. Long-term replacement of the Cl scan module Design or engineering tolerances could result in long-term change of the Cl system scan module where the calibration accuracy (e.g., target reference frame registration, tracking error, etc.) deteriorates over time. through time. Changing environmental conditions, such as temperature, could speed up the process. In order to combat long-term drift and ensure sufficient scan module positioning accuracy, the types of scan module calibrations described above could be performed periodically. A consistent measurement system that can automatically detect and implement updated corrections greatly benefits the end user. Automation and synchronization of the imaging system with the laser processing cell further simplifies the recalibration sequence, allowing measurement generation and detection to be performed automatically (or semi-automatically). Scanner field corrections In fixed optical laser heads, a single process beam / workpiece reference origin registration could be sufficient since the position of the process beam relative to the laser head is fixed. However, further extensions in fixed optical device implementations could involve multiple registrations in tandem for different defocus positions (e.g., different planes relative to the focal plane of the head). Complications arise for the overall registration calibration process when the laser head involves a beam scanning optical device. The scanning optical device allows the focus of the processing laser beam to move relative to the laser head. Examples of laser scanning heads include, but are not limited to, the 2D high power scanner and the 3D high power scanner available from IPG Photonics Corporation. In these scanner base implementations, the reference frame of the imaging system could be registered to the position of the process beam (and the reference frame) at multiple locations across the entire scanning field of the laser head. . In some applications, registration requirements could be relaxed by restricting the effective working area (or volume) of the scanning field. Similarly, in applications with reduced registration accuracy requirements, calibrations at multiple locations within the scan field may not be necessary. However, there are scan head hardware and applications where this additional registration might be desirable or advantageous. Example applications include single-mode laser processing applications, such as keyhole welding of electric mobility components, where the phase change region created on the surface of the workpiece by the single-mode beam of diameter narrow is small relative to the overall registration errors of the measurement system at different locations in the scanning field. In these applications, the lack or absence of additional calibration points could cause the measurement to be off-target in one or more regions within the scan field. The relevant positioning scales for some applications could be on the order of a few microns to a few tens of microns. Example hardware deployments where additional co-registration might be desirable or advantageous include systems where the measurement spectral band is different from the processing beam spectral band. In these systems, chromatic aberrations induced by various optical components within the head cause the measurement site to deviate from the focal position of the processing beam by different amounts for different positions within the scanning field. This deviation could be large enough to cause measurements to be taken at incorrect positions relative to the phase change region or specific features or configurations on the workpiece. An example of the types of corrections that could be applied to the imaging system scan module positioning commands, as a function of scan field position, to correct optical distortions in a laser scan head is shown in Figure 17. This example illustrates the types of 2D corrections that could be used for a 2D scan head. 3D analog corrections could be used to correct the 3D scan heads. In addition to scan field co-registration errors originating from chromatic effects, co-registration errors at different locations in the scan field could arise from other optical and geometric effects. For example, misalignment of the beam path of the Cl measurement system and the path of the processing laser beam through the laser head could cause similar errors in overall registration of the scan field. Heat effects on the head, such as thermal deformation, could also produce overall registration errors. Depending on the system and application, a general calibration across the entire scanning field may be sufficient to co-register the measurement and processing beams. However, in systems or applications involving a very high degree of co-registration, it may be desirable to perform more specific co-registration calibrations around the processing laser path as shown in Figure 18. Figure 18 shows shows an example of path-specific recording measurements of the imaging beam and process beam for an apparatus involving a laser scanning head. Specific calibrations could reduce overall calibration time (e.g., by limiting calibration locations to those relevant to the process) and could improve accuracy (e.g., by introducing calibration locations within a coarser overall calibration grid). As shown in the illustrated example, these calibrations could be performed at specific locations in the processing path and could be performed at positions around the path (e.g., the bonding or bonding perimeter). Similar calibration measurements could be used to compensate for changes in optical path length and changes in the focus of the measurement beam, associated with different positions within the scanning field. Synchronization of the imaging system with the laser processing system facilitates these calibrations. In this case, synchronization with the system's motion control (e.g., scanner position) could be used to automatically direct (or read) the focal position of the processing laser. Synchronization with the processing laser source, or its controller, could be used to indicate when the calibration process should be performed and when the imaging system is ready to perform the next calibration measurement. Primary Scanner Process Beam Tracking and Position Error Similar to the Cl system scan module corrections, laser scan heads could also use corrections to account for their own tracking errors, optical distortions, mechanical alignments, and thermal effects. A laser processing system with an integrated coherent measurement system could make use of the Cl measurement system (or its auxiliary detectors) to determine the scanner corrections of the laser head, the primary scanner corrections. Similar strategies described above can be used to calibrate the Cl system to perform primary scanner calibration. For example, the primary scanner could be used to generate a series of calibration marks on a target below the laser head. Measurements of the image deformation system (the coherent process radiation or some combinations of these) could then be used to determine the tracking or positioning errors associated with the primary scanner. A more specific non-limiting example includes using the primary scanner to mark a series of points on an overhead workpiece while traveling in one direction and another series of points while traveling in the opposite direction. The measurement system scanning module Cl can then be used, while the primary scanner is held in a static position, to make coherent measurements of the marked surface. The height base measurements of the coherent measurement system can be used to identify the locations of configurations or features marked on the surface of the workpiece. The positions of the configurations marked in one direction against the others can then be used to identify the tracking error of the primary scanner. The primary scanner could be used instead of (or in addition to) the Cl system scanning module to position the measurement beam at specific locations on the workpiece for the purpose of performing calibration measurements. In this case, synchronization is provided between the position measurements of the primary scanner and the imaging system. While it may be useful to perform these measurements with a fully calibrated imaging system, primary scanner calibration measurements could be performed in such a way that a complete calibration of the imaging system is not a prerequisite. Primary scanner calibrations could only be performed based on system commission or production. However, in some cases, periodic calibration could be performed to combat mechanical optical deterioration or changes in environmental conditions (e.g., thermal deformation). Dynamic calibration The systems described above could also be used to perform dynamic (i.e., process-specific) calibration measurements as described in the following examples. Typically, these measurements are performed for each type of laser processing application and for major changes in application processing parameters. Calibrations / abuses could also be performed continuously during the processing application to achieve high calibration accuracy, as well as to reduce laser station downtime (i.e., time not spent performing laser processing). . Minimum system downtime is critical in many high-throughput laser processing production environments. As with static calibrations, dynamic calibrations may also need to be performed periodically on high-precision processes to compensate for equipment tolerance limitations, temperature change, environmental fluctuations, mechanical vibrations, mechanical forces. dynamics during production, etc. Dynamic calibrations are also used to record imaging system measurements for aspects of the laser process that are specific to the laser process and / or workpiece. Aspects of the laser process could be detected as part of the dynamic calibration and feedback of the Cl system (or forward) to influence Cl characteristic measurements of specific aspects of the process. These aspects of the laser process include, without limitation, the following: the geometry of the process path; the speed of the process trajectory; the process path direction: the tangent angle of the process path; the process time; laser energy temporal profiles; optical path length changes around the process path and its local proximity; the displacement of the workpiece of the laser head around the process path and its local proximity; co-registration of the processing and imaging beam system along the process path and local proximity; changes in the focal positions of the measurement beam around the process path and its local proximity; the geometry of the phase change region; the extensions of the phase change region; the position of the phase change ruler; the radiation intensities of the phase change region (i.e., temperature); the position of the fusion pool; the geometry of the fusion pool; the position of the keyhole; the geometry of the keyhole; the size of the laser beam site; the energy distribution of the laser beam; the temporal characteristics of the laser beam (e.g., continuous versus pulsed wave, pulse width, pulse period, pulse frequency, pulse shape); the reflectivity profile of the measurement beam (i.e., surface reflectivity and / or subsurface reflectivity); lines of faith / references / workpiece data; and the dispersion of the measurement beam. Dynamic calibrations could be performed by taking measurements from a similar process before the process in which the measurements are processed (e.g., QA determinations). These calibration measurements could be stored, so that they can be implemented for the target process. In general, changes in the target process invite a stage of new calibration. In other implementations of dynamic calibration, calibration measurements are performed during the process for which the process measurements are performed. These calibration measurements could be performed immediately at the start of the process, so that the rest of the process can be monitored with a calibrated system. Calibration measurements could also be interleaved, or could be performed at the same time, with process measurements for improved accuracy. Phase change region measurements In addition to providing process monitoring quality determinations, phase change rule measurements could also be used to provide dynamic measurement system calibration measurements. For example, process radiation measurements from the phase change region allow process beam co-registration calibration measurements to be performed during laser processing rather than taking the system offline. This could be used in applications with high performance requirements. Figure 19 shows how the coherent imaging system using a double-coated fiber in combination with an auxiliary photodiode (e.g., the 100" system shown in Figure 3) can be used to determine the location of the center. process beam (1) during a laser process. In this example, the dual-coated fiber could include a dual-coated fiber coupler manufactured by Castor Optics. Similarly, Figure 20 also illustrates how 2D in-line camera measurements can be used (e.g., using the system 100' shown in Figure 2) of the phase change region and the measurement beam. coherent to determine process beam registration during a laser processing application. Similar measurements could be made using other contrast mechanisms, for example, optical path measurement of the Cl system, to determine process beam alignment during processing. Phase change region measurements could be used, directly or indirectly, to perform other process baseline calibrations. For example, Figure 19 shows how the rear region of the phase change region (PCR) could be detected by an establishment of a double-coated fiber and could be used to determine the process direction / tangent angle (2). Typically, this measurement is dependent on the existence of an imaging system reference frame calibration at the target reference frame. Similarly, Figure 20 shows how a 2D online camera image of the process could be used to identify the process direction of the PCR back region. Generally, this process involves an additional calibration step to register the camera reference frame in line with at least one of the reference frames of the imaging system, the scan head and the workpiece. Figure 21 shows how a point-based measurement could be scaled (for example, coherent height measurement, process emission measurement through the coherent system, process emission measurement through a coating fiber double) around the PCR. By synchronizing the single point measurement with the position around a circular scan module scan pattern (or similar), the features and resulting signal in the measurement signal profile could be used to identify the direction of the line central rear PCR and therefore the process direction. The centerline could be identified by a local maximum or peak (shown in Figure 21) in the signal as a function of the position on the scan path. The position on the scan path could then be mapped to the system reference frame Cl to determine the near-instantaneous trajectory direction in the system reference frame Cl (e.g., clockwise in the example above and counterclockwise in the example below). Similarly, PCR back length measurements could be used to identify processing rate or changes in processing rate. Generally, the length of the rear PCR increases with the processing speed. However, the exact nature could depend on other process factors such as material type, material geometry, laser site size, and shielding gas. Prior knowledge of these relationships, or process modeling (e.g., based on cooling rates), could be used with back length measurements to determine process rate. The process speed could then be used to direct the measurement system to measure at specific positions or times before or after the process. Measurements of other aspects of the phase change region could be crucial for measurement positioning during specific laser processing applications. For example, in keyhole laser welding, the alignment of the measurement beam with the vapor channel formed during welding is established to perform keyhole depth measurements using a coherent imaging system. Changes in the keyhole laser welding process, such as changes in process speed, could cause the location of the vapor channel to change with respect to the position of the focal process beam, as shown in the figure. 22. As illustrated in Figure 22, increases in welding speed could cause an increase in the delay distance of the vapor channel position behind the processing beam. Similarly, changes in the welding direction could cause a change in the direction of the vapor channel delay behind the process beam. Additional process effects, such as changes in geometry or material composition or periodic oscillation of the process beam, could also cause changes in the position of the vapor channel. Calibration measurements of the vapor channel position at one or more positions along the weld path are beneficial in achieving measurement beam positioning for keyhole depth measurements and could be used to establish position. of the imaging beam for keyhole depth measurements during the same process or for subsequent processes. Measurements from the Cl measurement system could be used to identify the position of the vapor channel based on the occurrence of a specific depth feature or configuration (e.g., the deepest measured depth, a cluster of points at a specific depth, the measurements with specific types of depth variations, measurements with specific levels or variations of signal intensity, etc.). Process radiation measurements could also be used to identify the position of the vapor channel. These measurements could include peak radiation levels, specific variations in radiation levels, radiation from one or more specific spectral bands, specific features in POR topographic radiation measurements, etc. Characteristics analogous to the vapor channel in laser keyhole welding could be identified and calibrated in other laser processing applications such as additive manufacturing, marking, cleaning and cutting. Pre-processing and post-processing calibration measurements Measurements of one or more configurations or characteristics created in a workpiece as a result of a laser process and measurements of one or more characteristics of a workpiece intended to undergo laser processing, could also be used for calibration of the dynamic system. These post-processing characteristics could be measured by the system (with or without auxiliary sensors) by measuring far enough behind the process in space or time or both. Because the measurements are made after the laser process, the measurements typically depend on height-based contrast mechanisms or external radiation intensity-based contrast mechanisms. In many laser processing applications, the process produces a change (e.g., in height, reflectivity, polarization, material density, etc.) that can be detected by a coherent measurement system or an auxiliary detector. Examples include a weld bead in laser welding applications, a solidified bead in additive manufacturing, changes in glass reflectivity in line marking applications, and a region of removed material in laser cleaning. By making measurements at specific positions relative to the reference frame origin of the process beam and with specific measurement scan patterns, additional characteristics of the laser process could be determined and used to direct future positioning of the measurement system. These dynamic calibration measurements could be used to construct a laser processing trajectory and other laser processing calibrations, with limited or no prior knowledge of the trajectory. In other cases, calibration measurements could be used to determine corrections for application to a set of nominal process parameters to correct for non-ideals in the process. For example, the coherent measurement system could have access to a nominal processing path input to a laser scanning head. However, physical limitations on the scan head (e.g. finite acceleration) could cause the true trajectory to deviate slightly from the commanded version. Dynamic calibrations could be used to correct these types of deviations. A specific example of these types of calibration measurements involves a series of linear scans of the coherent measurement beam perpendicular to and centered on the nominal weld path through the solidified weld bead (or similar markings along the weld path) while The motion control system (e.g., scanning head, robot, linear stages, rotating stages, etc.) realizes the motion trajectory, as shown in Figure 23. Figure 23 shows how the use of measurement lines transverse to the nominal laser processing path can be used to identify the difference between the nominal and actual processing paths. Often, transverse scans are offset (forward or backward) of the processing beam along the welding path. In this example, the base height measurements of a feature created by the laser process (for example, a marked line) are used as the calibration target. If the actual or actual motion path is the same as the nominal motion path (the bottom outline), the line appears centered on each of the cross measurement profiles and the feature or configuration appears as a straight line in the center of the image that is reconstructed from the linear scans. As the discrepancy between the actual and nominal trajectories increases (the upper diagram), the position of the line within each transverse measurement profile varies according to the deviations in the trajectory position and tangent angles. Deviations from the nominal motion path cause the feature to appear shifted and / or distorted (e.g., wider) in the image. These deviations could evolve as a function of position along the trajectory since the misalignment between the nominal and actual trajectories can change as a function of position along the trajectory. The example illustrates trajectory error detection using a height-base contrast mechanism. A similar strategy could be employed using back-reflected intensity base contrast mechanisms, process radiation contrast mechanisms, or a combination of all three. Additional sets of perpendicular scans, at different distances leading and trailing the process beam, during the motion path could also be used to more accurately identify these motion path corrections. The example above is a simple illustration of the types of scan patterns and strategies used to identify laser processing motion trajectories. More complex scan patterns could be used to construct dynamic corrections. Other examples could also involve the use of coherent imaging signal correlation, coherent imaging height measurement correlation, 2D online camera image correlation, tracking operations similar to those in a mouse computer optics, detecting process emissions, or back-reflected light beams. Examples of dynamic calibrations (identification and / or correction) that could be applied to the imaging system to monitor laser processing applications include, without limitation: processing path error; the tangent angle of the processing path; the speed of the processing path; optical path length changes induced by the optical beam delivery device; the extensions of the laser interaction region; the position of the laser interaction region; the extensions of the phase change region; the position of the phase change region; the inclination of the workpiece; and the curvature of the workpiece surface. For example, the local inclination of the workpiece surface could be calibrated by performing a repeated circular scanning pattern of the measurement beam (within the scan module reference frame) while the motion control systems of the scanning station laser (or laser scanning head) drive or move the process beam through its processing path. In most implementations, the process beam is deactivated during this process so as not to damage the workpiece. Typically, the circular scanning pattern is performed at a high frequency to achieve a large number of complete circular periods measured during the laser processing path. Often, the frequency is governed by hardware limitations of the coherence imaging system's scanning module. For each circular scan, the Cl system height measurements taken across the circle are mapped to their corresponding XY positions around the circular scan pattern. A plane fit to the of the trajectory (mapped to the circular scan number). The change in tilt angle, as a function of the welding path, could then be used to modify the Cl system measurement scanning strategies and data processing algorithms while monitoring the laser process. This local surface tilt calibration measurement process is shown in Figure 24. While the laser head moves along its motion path path through a part with surface curvature, as shown in the figure 24, the Cl system scanning module scans the measurement beam in a periodic circular pattern taking Cl measurements synchronized with the position of the measurement beam. In this example, the circular pattern is generated with respect to the reference frame of the system scanning module Cl (which is opposite to the surface of the workpiece) to measure the inclination of the workpiece with respect to the reference frame of scanning module. Height measurements Cl are mapped to their corresponding circular beam scan pattern iteration and are additionally mapped to their corresponding XY position within the pattern. Once the Cl height measurements within a cycle are mapped to their XY positions, a flat fit is applied to the data (X: the X position, Y: the Y position, Z: the Cl height measurement). From the plane adjustment coefficients, a surface perpendicular vector is generated, which represents the instantaneous local surface inclination. The surface perpendicular vector is then mapped to a suitable angular coordinate frame of the system (for example, the inclination angle along the welding path direction). This process is repeated for each scan cycle. A timestamp is assigned to each cycle (for example, the time at which the midpoint of the cycle occurs with respect to the trajectory start time), allowing the surface tilt angle to be plotted as a function of time to along the laser processing path. Tilt, as a function of the position of the processing path, could be used by the Cl system to provide positioning corrections to the Cl system scanning module and could be used to correct the Cl system height measurements (not shown ). While a circular scan pattern was used in this example, other scan patterns could also be used for this calibration. These scan patterns could include, but are not limited to, sampling a finite number of points distributed around the XY scan field, scanning a cross pattern, scanning a spiral pattern, and scanning a cross pattern. rectangular mesh. Any scan pattern that provides enough points (at least three) to reliably fit the surface is sufficient for this calibration. Similarly, while a flat fit was used in this example, other data processing algorithms and surface fitting techniques could be used for this calibration. For example, more involved surface curvature adjustments could be used to identify first-order tilt correction as well as additional surface distortion. Data processing and fitting techniques could take an iterative procedure or could perform direct calculations. Any processing technique that produces one or more surface curvature or tilt metrics is sufficient for this calibration. Processing beam oscillation pattern identification and registration For certain types of laser processing applications (e.g., welding of highly reflective metals such as copper or aluminum), oscillating the process beam in a small periodic mode is common to improve process yields. Similar measurement techniques as described above could be used to specifically identify aspects of the oscillation process to improve registration of the measurement beam relative to the oscillation process beam. These measurements could also be used to influence the way measurement data is subsequently processed and analyzed. Examples of relevant aspects of the oscillation process include, without limitation: the oscillation phase; the form of oscillation; the period of oscillation; geometric deviations from the nominal oscillation shape; and the changes to the phase change region induced by the oscillation process. Example workflows that benefit from calibration measurements The following section provides examples of the types of workflows that benefit from or are enabled by the calibration measurements described above. The workflows described here could be realized by exchanging the device modalities, contrast mechanisms, and calibration types described above. Similarly, workflows could also be realized through the use of different communication methods, such as those described below. Automatic calibration and cell synchronization processes Automation and even semi-automation of many of the calibration processes identified herein provide numerous benefits to the end user. Automation minimizes user interaction with the laser processing system and imaging system. This results in the end user using fewer resources to operate the equipment (e.g. less trained personnel, less training and time, etc.). Minimal user interaction also results in reduced risk, or reduced consequences, of user error. User error during a system calibration process can have consequences for measurement accuracy and process reliability since this error is propagated to all subsequent measurements performed by the system. Similarly, automation reduces the overall time to perform a calibration and allows calibrations to be performed at times that are most convenient for the laser process or production environment, rather than at times that are most convenient. for the operators. Different calibration processes involve different levels of synchronization between the laser processing system and the imaging system. Synchronization could be achieved through direct communication or signaling between the laser processing system and the imaging system or it could be achieved, indirectly, through communication with one or more process controllers. Synchronization between the imaging and processing systems could include, but is not limited to, one or more of the following: control of the imaging system of the position of the processing laser; control of the processing laser energy profile imaging system; controlling the imaging system for predefined laser processing jobs; synchronization of imaging system with the position of the processing laser; synchronization of imaging system with processing laser energy profile; synchronization of imaging system with predefined laser processing jobs; and the predefined processing laser jobs compared to the predefined imaging system calibration jobs and synchronized by a common start signal. Forms of synchronization could include, without limitation: a common external start signal; a common external synchronization signal; user configuration of the corresponding imaging and processing system jobs; positioning signals; energy profile signals; digital signals; analog signals; optical signals; the optical signals generated by the laser process itself; and common industrial communication protocols (e.g. TCP / IP, Ethernet-IP, Profinet, etc.). Synchronization could also be used to ensure that the imaging system receives a sufficient signal for the calibration measurement. This could also be used to ensure that the laser processing performed for calibration does not cause too much damage to the calibration workpiece. In addition to calibration of the imaging and processing systems, synchronization between the measurement system and the processing system / cell could also be used to compensate for deterioration in processing performance with respect to time. General wear and tear of laser processing station components (e.g., optical device, fixture and gas supply systems) could slowly degrade laser processing performance with continued use of the system. Measurements of laser processing station performance by the imaging system could be used to identify this degradation (e.g., through reduced levels of process radiation) and to correct system performance (e.g., increasing the commanded laser power to compensate, automatically replacing system components, providing an indication to the user, etc.). Similar detection and correction could be made for process-induced damage to the station, such as contamination of the optical protection device of the laser head by process removal. Calibration at the time of manufacturing At the time of manufacturing, it is common for coherent imaging systems to undergo calibration operations to improve the accuracy of the measurement system. For example, subcomponent variability, as introduced as a result of design tolerances and its own manufacturing variability, is measured and calibrated. When possible, calibration of the Cl system is performed with the measurement system integrated into the laser head that will be used in the laser processing application. However, due to real-world limitations, integration with the laser head before the Cl system reaches its end-use location is not always possible. In this case, the Cl calibration could be performed with the same model laser head, a similar type of laser head, or a substitute calibration head. Deviations between the laser head used for calibration and the end-use laser head could be imperceptible and no additional calibration is performed in the system commission. In some applications, such as those with high precision requirements, additional calibration operations could be performed in the system commission, as will be described later. The following example illustrates aspects of the calibration process that relate to the integration of a Cl system into a laser scanning head. The order of the calibration processes described herein is not a limitation and in some implementations, certain calibration operations could be performed in parallel. Before the calibration process is performed, the Cl system is mechanically integrated with the laser scanning head. Some laser heads, such as those available from IPG Photonics Corporation, include a port dedicated to Cl system integration. Other laser heads may require interconnect hardware to couple the Cl system with an existing camera port. online (or other sensor). Other laser heads could include physical modifications to the mechanical set points, optical beam paths, and optical delivery device to accommodate the coherence imaging system. After mechanical integration, electrical and communication interconnections with the laser head and Cl system are established. In a fully automatic calibration process, the laser head, Cl system, laser source and where applicable, the cell movement control equipment, all are in communication with each other (direct or indirect). The terminology for the components described herein refers to the specific piece of hardware and the hardware drivers. In semi-automatic calibration processes, some of the above communication links could be established, although the user is also involved in the process, providing the missing communication and synchronization elements. For example, when the laser head and Cl systems are readied and prepared to perform their calibration operating routines, the user could press the button that activates the laser firing. In turn, the laser provides a synchronization signal to initiate operations of the laser head and the Cl system. In a fully automated environment, communication between the laser head, Cl system, laser source, and motion control subsystems is generally controlled by one piece of equipment that acts as the Process Master. The main station or process master has knowledge of the different aspects of the laser process (or calibration process) and knows how the subsystems must be synchronized in order to achieve successful operation. In some applications, the main station or process master could be realized by additional hardware, such as a programmable logic controller (PLC), a robot interface, an external computer / server, a smartphone, a tablet computer, or a microcontroller. In other applications, one of the subsystems (for example, the laser head controller, the system controller Cl, or the laser controller) could take the role of the process master. Often, communication is directly achieved through two-way communication between the process master and each subsystem. However, in some applications, some subsystems could synchronize with other subsystems and communicate indirectly with the main station or master. Communication could be in the form of digital signaling, analog signaling, peering communication protocols (e.g., TCP / IP), or some combination thereof. Once mechanical, electrical and communication integration has been established, calibration procedures could be performed. A calibration target could be used at the working distance of the laser head. Once a calibration target has been set by the user, or automatically by other equipment in the cell, the user, or the cell, indicates to the process master (PM) that the target is in place. The PM instructs the Cl system to automatically perform its depth of field calibration, which may include adjusting the Cl system's optical delivery device to better focus the measurement beam on the workpiece and may include adjusting the optical paths. reference within the Cl system to better match the beam delivery path of the laser head. During depth of field calibration, the Cl system performs measurements of the calibration target and electromechanically adjusts its own subcomponents based on the measurements. In most calibration routines, the electromechanical adjustment and subsequent measurement are performed, iteratively, until the resulting measurement is sufficiently optimized or reaches a target value. Once the calibration is complete, the Cl system signals the PM. During this calibration routine, laser head scanning and laser output functionality are not required. The PM leaves these subsystems offline or in an inactive state so that their operations do not affect the calibration process. Similarly, the tracking error calibration of the Cl system scanning module could be automatically calibrated. In some tracking error calibrations, only the calibration target and the CL system are performed. In these calibrations, a calibration target with specific characteristics (for example, sharp edges) is placed below the laser head. Once the target has been placed, the PM instructs the system to perform its tracking error calibration. Tracking error calibration measurements could be performed as described and illustrated above. In an automatic environment, calibration measurements are processed by the Cl system and are fed back to the Cl system to adjust its scan module behavior accordingly. In some cases, the mapping between the calibration measurement and the behavior changes of the scanning module might be sufficiently known that a non-iterative or repetitive procedure is sufficient. However, in other cases calibration measurements and scanning module behavior adjustments are performed, iteratively, until the tracking error is sufficiently calibrated. Once the calibration is complete, the Cl system signals the PM. In some tracking error calibration routines, the calibration target may not have specific features designed for calibration. In these cases the laser head, laser, motion control equipment, or some combination thereof, could be used to create the specific characteristic used for tracking error calibration. In these cases, the PM communicates with both the Cl system and the feature creation team to ensure that the feature or configuration is created at a specific location or at a specific time to allow calibration to be performed. In some cases, this could involve marking similar features on the calibration target with the laser and communicating the location (in space and / or time) of these features with the Cl system so that it knows when and where to perform its calibration routine. In the case where process radiation (which is opposite to the most permanently marked feature on the material surface) is used to create the measurement signal for the calibration measurement, precise temporal synchronization between the trigger events is desirable. laser and the Cl system to ensure that Cl system measurements are made when process radiation is emitted. The PM could communicate specific process parameters to the laser, laser head, and motion control equipment as desired to improve the signal detected by the Cl system. These parameters could be known a priori, or could be optimized by means of feedback from the Cl system. For example, the PM could fire the laser with a known set of parameters, could command the Cl system to perform its measurement, could receive feedback from the Cl system regarding measurement signal levels (e.g. example, no signal, low signal, good signal, high signal), then adjust the laser parameters accordingly. Once the tracking error is calibrated, it is used by the Cl system to more accurately synchronize the Cl measurements with the commanded positions of the Cl scan module and ultimately the measurement positions on the workpiece. Instead of direct low-level control of process parameters by the PM, each subsystem could have predefined sets of process parameters (i.e., jobs) that are called by the PM in response to feedback from the Cl system. Similarly, process beam and workpiece reference frame registration could be automated through synchronization between a process master and appropriate subsystems. An automatic version of these calibration routines could be performed as follows. The PM signals or instructs the cell to automatically load a calibration target below the head. This could be done by an automatic robotic arm or by notification to a cell operator. The cell then responds to the PM (e.g., via response from the robot or input by the cell operator) to indicate that the target has been loaded. Once the target has been loaded, the PM signals or instructs the laser scanning head to position the laser beam at its own reference frame origin. In some cases, accurate co-registration of the process beam could involve an initial “pre-scan” of the Cl system to acquire background signal levels or reference geometries. In these cases, the PM signals the Cl system to perform the prescan measurements. Once the measurements are completed, the Cl system signals the PM. The PM then signals the laser to operate to generate the process beam variable signal for the Cl system, for example, as described above. In some implementations the laser is operated to erode the calibration target and the Cl system measures the resulting eroded feature. In other implementations, laser interaction zone process radiation measurements are performed by the Cl system while the laser is operating (or only after the laser has been operated). The PM is responsible for synchronizing the Cl system measurements (e.g., via an acquisition signal, such as a digital elevation edge) to laser operation. Once the Cl system has completed the calibration measurements, it signals the PM accordingly. The Cl system uses this calibration to re-center its reference frame accordingly and performs subsequent measurements on a centric process beam frame. As described above, in addition to signaling full calibration, the Cl system could also provide feedback to the PM based on the levels / quality of the measurement signal. In turn, the PM adjusts the laser processing parameters to improve measurement signal levels. This feedback could be provided and implemented during the calibration procedure itself or after the calibration measurements are completed, so that the calibration process could be restarted with improved operating conditions. For some calibrations, the routine could be performed multiple times to make use of statistical data processing (e.g., averaging) or adjustment to improve the calibration result. For each iteration, the same calibration target region could be used, a new location on the target could be used, or a new target could be used. Orientation and scale calibrations of the workpiece reference frame are performed in a similar manner. The PM signals the cell to load the calibration target (or move the target to a new location). The cell responds to the PM when the target is ready. The PM then directs the laser scan head to mark a pattern (e.g., a plus sign or similar configuration) to indicate the scan head's coordinate axes on the workpiece. Once completed, the head signals the PM, which in turn directs the Cl system to perform its calibration measurements. This example could be the Cl system that performs a series of coherent measurements while its scanning module moves the measurement beam along a rectangular mesh scan pattern across the marked feature or configuration. The system data processing unit Cl then unrolls the coherent measurements to map them back to the rectangular grid on the surface of the part and uses image processing algorithms to identify the pattern configurations marked on the surface of the workpiece. . The Cl system then calculates the orientation and scale of these configurations relative to its own reference frame. The Cl system then uses this information to update its own reference frame calibration. Once the calibration is complete, the Cl system signals the PM. The Cl system automatically applies these reference frame calibrations to its subsequent measurement operations and scan module commands to achieve positioning of the measurement beam in the target reference frame. Since multiple calibration sequences are generally used by the Cl system, the Cl system could keep track of its own calibration status to indicate, for example, which calibrations have been performed, when certain calibrations have been performed or updated, which calibrations will still be performed and which calibrations are due for an update in the future. Once a calibration is completed, it is applied by the Cl system to make calibrated measurements for laser processing applications. The PM or cell could also keep track of the calibration status of the Cl system. The Cl system manufacturer could use this information to identify when a system is fully calibrated. For applications involving the integration of the Cl system into a laser scanning head, it is often advantageous to co-register the measurement beam with the Cl system laser beam at multiple locations across the entire scan field. the laser scanning head, to accommodate optical distortions, such as chromatic aberration. Synchronization between the generation of the process beam variable for Cl detection and the Cl system measurement is achieved in a manner similar to that described for the process beam recording process described above. However, scan field calibration involves additional automation considerations for the purpose of synchronizing the registration process in conjunction with various locations around the scan field. The PM could have knowledge of the scan field calibration positions. This could have this information pre-programmed or could request the information from the laser scan head and / or the Cl system. Similarly, the laser scan head and the Cl system could have preloaded configuration settings to perform this type of calibration and the PM could be used to synchronize the processing and measurement at each position within the scan field without knowing the precise coordinates of the scan field. The PM directs the laser scanning head and the Cl system to the first position within the scanning field. It then performs a similar sequence of operations in the process beam co-registration step described above to achieve synchronization between the scanning field position, laser firing and Cl measurement. calibration has been completed for the first position, the Cl system signals the PM. The PM directs the scan head and the Cl system to the next position where the process is repeated. This procedure is performed until the positions within the scanning field have been calibrated. The Cl system uses scan field calibration to implement Cl system positioning corrections at various positions within the scan field. In most applications, the Cl system involves signaling (directly from the scan head controller or indirectly via the PM) the scan field position, so that the PM could apply appropriate scan field correction. The Cl system could perform this correction using a lookup table generated by the calibration measurements or a model (e.g., a fit) of the calibration measurements. Scan head applications could also involve Cl system optical path length calibration measurements as a function of scan field position. In most laser scanning heads, the optical path length of the Cl system measurement beam changes as a function of the scanning field position, for example, due to increasing custom geometric path lengths. that the scanning head deflects the beam away from its origin or due to changes in the amount of focusing optical thickness that the beam passes through at a given scanner position. An optical path calibration could be automated in a similar manner to the scanning field process beam ensemble registration calibration. Synchronization with the laser is not required for this calibration. The PM orders the laser to turn off or be in an inactive state. The PM signals the cell to load a planar calibration target, or a calibration target with a known surface curvature and inclination. Once the part is loaded, the cell points to the PM. The PM then directs the scan head to a specific position within the scan field and waits for the scan head position signal. Once in position, the PM directs the Cl system to perform its calibration measurement. Often this measurement is in the form of an optical path length measurement. The measurement is then processed by the Cl system to determine the deviation of the optical path. In the case of a known curved or inclined surface, the Cl system processing unit performs flatness corrections to the optical path deviation measurement. Optical path deviation is usually measured relative to the optical path length to the workpiece at the origin of the scanning field. However, other references could be used (for example, a plane out of focus of the working plane of the scan head by 2 mm). Once the Cl system has made its measurement at a specific position, it signals the PM, which in turn signals or instructs the scan head to move to the next position and the process is repeated. Once optical path calibration has been performed at target points across the entire scan field, the system processing module Cl creates a lookup table or model (e.g., a fit) for the purpose of implement optical path length corrections as a function of scan field position when performing process measurements. As performed to co-register the process beam about the scan field, the Cl system uses knowledge of and timing for the scan field path during a laser processing application for the purpose of implementing corrections. This is usually achieved through direct or indirect communication with either the PM or the scan head. This communication could be done at various times including: before the process is started to provide the Cl system the ability to perform calculations to prepare for process measurement; in real time during laser processing application; and after a trial run of the application. Similar calibration measurements could be made about the scan field to calibrate the following: the optical spread of the measurement beam as a function of the scan field position; changes in the focal length of the measurement beam as a function of scanning field position; changes in the scale of the workpiece reference frame as a function of the scan field position; and changes in workpiece reference frame rotation as a function of scan field position. While automatic calibration procedures are described herein in the context of a completed cell assembly, it is possible to perform certain calibrations only with the relevant subsystems and submodules. For example, optical path calibration could be performed in a cell without an operational laser. System commission To limit the workload during system commissioning, since as many calibration processes as possible could be performed at the time of manufacturing. However, due to the restrictions described above, it is not always possible to integrate the Cl system with the cell or laser head before commissioning. Similarly, while calibration may have been performed during system manufacturing, recalibration of certain aspects of the system may be desired as a result of misalignments due to shipping and installation. In general, the implementation of calibration procedures during system commissioning reflects this at manufacturing time or a subset of procedures. In this case, the process master could similarly be the Cl system or a controller at the end-use location. Instead of performing some of the calibration routines in their entirety, automatic Commission checks could be performed to determine which calibrations are still accurate and which need recalibration. Generally, these automatic commission checks involve the same type of synchronization and communication between the different subsystems and the process master as is performed for full calibrations. However, the operations are generally less time intensive. For example, an optical path calibration check might involve performing optical path deviation measurements on a small subset of target points within the scan field. If these measurements agree with those taken during manufacturing of the system, then the calibration is considered accurate. If the check fails, the optical path calibration is performed again. As described above, the Cl system or process master could keep track of its calibration status for presentation to the individual Commission system. This could be used, for example, to inform the individual of remaining procedures, it could be used to block certain cell operations until the commission is completed, or it could be used to provide an announcement to the user that the commission is completed. While PM could be used to automate the commissioning process, limitations in cell signaling and communication schemes could involve some manual interaction (for example, loading calibration targets and pressing a button when they are loaded). Measurement job calibration monitoring and updating In laser processing applications, Cl system measurements of the phase change region provide important information about the process. In many of these applications, Cl measurements targeting specific subregions of the PCR are performed to obtain target process information. For example, in keyhole laser welding, alignment of the measurement beam with the vapor channel created in the welded part during the welding process is desirable to measure the depth of the keyhole. In many laser welding processes, the position of the vapor channel relative to the processing beam is dependent on many factors including, without limitation: the type of material; the geometry of the material; the speed of the process; the energy of the process; the trajectory of the process; oscillation patterns; the deployment of shielding gas; gas suppression techniques; environmental conditions; and the blur. Often, a calibration to determine the position of the vapor channel relative to the process beam for a given process, or subregion of a process, is performed by the Cl system. Once this calibration has been established, it is often accurate for small disturbances for the process parameters and conditions described above. However, a recalibration of the vapor channel position might be desirable if large scale changes exist. Similar calibrations to aspects of the process parameter space could be performed in other laser processing applications. In a laser processing cell with an integrated Cl system, automated workflows could be established to perform process-specific calibrations. In the case of keyhole alignments during laser welding, specific alignment jobs could be defined within the Cl system. These alignment jobs could be run before each new type of process to determine calibration. These could also be performed periodically and could be interspersed with laser process measurement work to verify or update the calibration as desired. A keyhole calibration job could be a sequence of coherent measurements around the process beam center targeting a specific coherent measurement signal configuration (e.g. deepest depth, specific depth variation, specific range depth, specific signal intensity levels, etc.). Similarly, process radiation measurements, as described above, could also be used to perform keyhole calibration measurements. Once measurements are made, the system processing unit Cl performs algorithm or image recognition routines to identify the specific calibration. In addition to updating the way the Cl system positions its measurement beam to measure the vapor channel, keyhole calibration measurements could be used to assign a good metric for measurement jobs (or aspects of measurement work) of the laser process. . This good metric could be used as a reliable indicator for output or could be used to provide an announcement to the user or process master that operations should stop until a new calibration is applied. In some embodiments of the apparatus, the Cl system subcomponents could allow keyhole calibration measurements to be performed in parallel to the keyhole measurements of the laser process itself. Here, there is no need to alternate or intersperse calibration measurements with process target measurements. Instead, keyhole calibration measurements could be performed during the process itself and could be applied to the Cl system in real time or near real time. It is also possible to perform these calibration measurements alongside process measurement work through resource sharing techniques. For example, keyhole calibration measurements could be performed in addition to keyhole depth measurements by adjusting the target position of the measurement beam, relative to the expected position of the keyhole, for a certain portion of the depth measurement period of the keyhole. keyhole and at certain intervals. This signal could be compared against the nominal keyhole position signal to determine if an improved calibration exists. This comparison could be a function of signal characteristics, such as signal intensity, signal density, signal variation, etc. While a process might be nominally constant, periodic keyhole recalibration might be desired due to uncontrolled changes in the process environment. These uncontrolled changes include, but are not limited to, thermal changes to process equipment, mechanical wear on process equipment, contamination in the laser head optical device, variations in process raw materials and process specifications. component, process fixture changes, thermal changes to the Cl system, and mechanical changes to the Cl system. In some implementations, calibration measurements are performed by the Cl system, processed by the Cl system, and applied by the Cl system, automatically, without user intervention. However, in other implementations, physical or regulatory constraints might involve some level of user interaction (for example, recognition of an updated calibration) before the new calibration is implemented. Maintenance and registration and user / external communication of automatic process Automatic calibration measurements performed during a series of similar laser processes provide the data to enable long-term statistics generation, process trend analyses, and cell operational health monitoring. For example, by collecting the backscatter intensity of the imaging beam off a workpiece surface with respect to time, it is possible to observe the decrease in intensity as a function of time. The decrease in intensity could be associated with contamination of the laser head cover glass as more material is processed. Similarly, this could also be associated with the aging of a light source or greater contamination of the material. By establishing additional objective calibration points, such as those within the laser head and those below the laser head, it is possible to isolate sources of decreased intensity. This insulation is useful for identifying contaminated cover glass. Once identified, the Cl system could provide an announcement to the user directly, or indirectly via the process master, to indicate that a new cover slide should be used. In other systems, this signal must be automated so that the cover glass is replaced more frequently. The announcement to the user could be in the form of visual cues in the cell (e.g., LEDs, displays), audio cues from the cell (e.g., bell ringers, buzzers), or electronic notifications (e.g., smartphone applications, tablet computer applications, wearable technology, PC programs, email). Similarly, recording other calibration measurements could be used to identify process titer changes. For example, small changes to the keyhole position calibration with respect to time could be associated with changes in the process and part fixture environments. These long-term trends could be used to identify the source of the change and to remediate the process and its equipment. Recording co-registration calibrations of the process beam could be useful in identifying problems with the optical components associated with beam delivery to the head. Trends could be compared over time and against other data sources to identify problems, such as thermal deformation, damage to optical components, and loose optical components. In many laser processing applications, knowledge of the process beam focal point allows process results of sufficient quality. Positioning the workpiece surface relative to the focal plane of a processing laser beam is important for proper coupling of energy into the material during the process. Often, the material undergoing laser processing is positioned with its surface in the focal plane of the laser beam to maximize energy coupling at the material surface. However, shifting the material surface of the focal plane (often referred to as defocusing) to distribute the energy of the laser beam across a larger surface area is also common. Those skilled in the art could intentionally blur the beam toward or away from the material. Similarly, the ability to record the spatial position of the laser site or location across the workpiece surface could ensure that the target material region is subjected to processing. In a laser processing station with an integrated Cl system, it is possible to use the Cl system as a guidance system to locate the focal plane of the process beam, relative to the surface of the part, as well as to locate the position lateral (XY) of the process beam site across the material surface. The information provided by the Cl system about the 3D focal point of the process beam could be used by a machine operator during adjustment for a new part or could be automatically communicated to a machine controller (e.g., a PLC, a controller robot, a scan head controller, etc.,) in order to activate the optical or mechanical adjustments to position the focus of the process beam in the desired position in relation to the workpiece. These adjustments could be desirable for a wide variety of applications, including, but not limited to, high tolerance processes (e.g., laser processing with a single mode beam) and assembly line processes where the variation of Material tolerance or process fixture degradation could require active compensation from one part to the next. For a Cl system that will be used as a guidance system, the Cl system could be calibrated to the focal plane and lateral position of the process beam. Other examples illustrated herein outline possible techniques for calibrating the lateral position of the process beam on the surface of a material. These techniques could also be applied in the following example to calibrate a Cl system with the focus position of the 3D process beam. For simplicity, the example here includes scanning the Cl system measurement beam in a rectangular pattern around the surface of the material and using the Cl system height measurements to resolve the location on the material surface marked by the beam. of process. However, other modalities of Cl system measurement (e.g., blackbody emission measurement) and other scanning strategies could also be employed. Similarly, the Cl system could communicate directly with the process controller to perform the calibration process, automatically, or in some cases it could require user interaction. An example automatic calibration process is described in more detail below. The process controller communicates with the motion control equipment to position the laser head relative to a calibration target or the workpiece. This could involve loading a target material below the laser processing head or positioning the laser processing head at a new spot location on the target material. The process controller commands the laser (for example, through digital signaling or standard communication protocols, such as TCP / IP) to mark a location on the target surface. The parameters of this process could be predefined by the controller, could be preset within the laser itself, or could be obtained through communication with the Cl system. Once the site or location has been made, the process controller commands the Cl system to perform its calibration operation. The Cl system could perform a rectangular scan (or other patterns as described herein) across the surface of the part to capture the demarcated area on the surface of the workpiece, as shown in the image in the figure 25. Using the contrast detection algorithms described herein, the Cl system identifies a (variable) laser site diameter using the imaging data it collects, as shown in Figure 25. Although the signal appears in the image, the detection algorithms resist the effects of the signal, and the signal size can be reduced by increasing the numerical aperture of the beam delivery system for the Cl system. Once Cl system calibration measurements are acquired, the Cl system processes the information to automatically calculate quantities about the demarcated site, such as its central position and diameter. It is noted that by adjusting or finding centroid peaks in the axial measurements of the Cl system, the effects of quantization signal and noise on the image can be reduced. In some embodiments, a secure software configuration allows the manufacturer to limit the axial resolution made available to end users in order to better comply with government regulations regarding device performance. Additional extensions to this procedure include repetitive scanning of the Cl system in different mosaic search areas and / or modifying the scanning area to better locate the site or location. Similarly, the Cl system could iteratively communicate with the process controller (or directly with the laser) with additional firing sites to enhance contrast or to provide more precise temporal synchronization to laser processing even if was necessary. The central position of the XY site is used as a variable for the lateral position of the process beam on the workpiece surface. The site diameter could be used as a variable for the diameter of the process beam on the material surface, although more indirectly as process thermal effects generally produce a much larger mark on the material surface than the beam site size. of process. Additional extensions to this calibration procedure include performing a series of this type of calibration at varying offset distances from the laser head (i.e., the distance between the laser head and the workpiece surface). This series of measurements generates the (variable) site diameter as a function of the distance displaced. During these measurements, the displaced distance could be communicated to the Cl system via the process controller or could be measured directly by the Cl system itself (via its height measurement capability). For example, Cl system height measurements near the periphery of the rectangular scan area (i.e., regions that do not contain the laser marked site) could be averaged to produce a Cl system measurement of the distance displaced to the surface. of the work piece. The (variable) site diameter as a function of the displaced distance is then analyzed to determine the focal plane of the laser beam. In some cases, this analysis could include finding the displaced distance associated with the minimum site diameter. In some cases, fitting these data to a function (e.g., a Gaussian beamwidth equation) could be used to increase the robustness of the calibration. In other calibration routines using non-laser processes, other metrics could be used as a function of offset distance to identify the focal plane. Examples could include: maximization of blackbody radiation intensity, maximization of site depth, maximization of site size, maximization of site height variation, minimization of height variation site, maximization of blackbody radiation, maximization of blackbody emitter diameter, local maximization of blackbody emitter diameter, minimization of blackbody emitter diameter, maximization of site symmetry ( minimizing astigmatism), minimizing laser traced feature width, and maximizing laser traced feature width. The same site diameter (variable) could also be used as a function of the displaced distance data to generate a variable for the corrosive process beam. This information could further be stored or analyzed by the Cl system to produce an indication of beam quality. The information could also be communicated to the laser cell, or a user, for external analysis. Beam quality analysis is useful during laser and cell commissioning operations to ensure proper functionality. Similarly, periodic measurement and analysis of beam quality, or measurement and analysis after expected damage behavior (e.g. generation of spatter on the laser head cover glass, crushing, etc.) could be used. of mechanical systems), to verify the continuous quality of beam delivery and / or to identify problems. Similar measurement and analysis could be used to identify suboptimal beam delivery performance (e.g., thermal deformation resulting in a change in focal position). It should be noted that, for certain combinations of energy beam parameter and material, the minimum in the apparent diameter of the site (variable) could exist on one or more sides of the actual minimum of the process beam focus. This is because at the highest intensity (the narrowest focus), some processes will initiate a keyhole (vapor capillarity) mode more quickly and thus absorb more total energy, leading to a larger and more thermal effect. this way, to a larger (variable) apparent site diameter. Regular measurements from a process beam calibration site could also be used over time to track cell health and to identify process problems. By recording calibration metrics (e.g., site XY position, site diameter, blackbody intensity, etc.), the Cl system could analyze trends in the data to indicate potential problems in the beam supply components. For example, the glass cover optical device could become contaminated by process ejections and could incur beam transmission problems over time. This could manifest as a smaller marked diameter of the site, or in the case of the blackbody, a weaker blackbody emitter. Similarly, trends in the recorded metric could be observed due to loose, damaged or suboptimal beam delivery optical device. This information could be presented directly by the Cl system (for example, through an advertisement) or could be communicated to the user of the Cl system or laser cell controller for external analysis. All of these procedures apply variations of this principle: the same energy applied to the same material with the same temporal energy profile should produce very similar results. If any of these surface mark measurements vary substantially with respect to time, it is likely that those variations are variable to variations in performance of the laser source and beam delivery system. The process beam calibration process could additionally be combined with other Cl system calibration measurements to reduce the number of steps or the total time required for multiple calibrations. For example, the unprocessed areas at the periphery of the rectangular scan area height map could be used to calibrate the workpiece tilt and optical tilt introduced by different beam delivery paths (mostly relevant in beam heads). beam scanning laser). Similar recording of these additional Cl system calibration metrics could be used to identify additional aspects of cell health and process issues (e.g., cell fixture wear). During certain Cl system calibration procedures, the use of a readily available material as the calibration target (e.g., sheet metal) may be sufficient. For some Cl system calibrations, the calibration target could be the workpiece undergoing laser material processing (i.e., a pre-production part) or a workpiece after it has undergone material processing. (i.e. a later production part). For other Cl system calibrations, a specific manufactured calibrated target may be required for calibration. In some embodiments, system Cl and / or camera data are used to identify the direction of travel for a motion system (e.g., a robot, linear axes, or linear conveyor system) relative to the head. Similar Cl system measurements could be used to identify workpiece placements, workpiece orientations, fixture placement, and fixture orientation relative to the head. This would allow the precise calculation of so-called “flying welding” or coordinated movement operations. Finally, in some embodiments, the calibration target is rigidly coupled to a non-workpiece object that would allow location and orientation of the non-workpiece object relative to the beam delivery and movement control systems (e.g., a robot). Cl system health monitoring In addition to being useful for identifying process problems and laser cell problems, automatic calibration measurements are useful for monitoring the status and health of the Cl system itself. Calibration measurements could be performed periodically for the express purpose of determining the operational status of the Cl system. Calibration measurements could be performed for the purpose of calibrating another aspect of the Cl system, although it could also be used or for the purpose of evaluating the health of the Cl system, or changes in the condition of the Cl system. In general, a very wide binning width from repeated process beam alignments or other calibrations could be indicators of inadequate performance of the laser system or Cl system, or an inadequate situation in the automatic alignment process. In any of these cases, embodiments of the present disclosure could use a threshold in the distribution of automatically calculated lineups as a trigger for the external announcement or signal to request assistance or to stop further processing until the condition or condition can be remedied. failure situation. Back reflection measurements from calibration targets inside the head could be used for identification of an aging light source. Declining light source output power trends could then be fed back to the Cl system to increase the light source drive current, or similarly a higher nominal output power could be commanded to achieve similar levels of output power as performance degrades with respect to time. Similar calibrations could be used to detect and implement corrective actions for the following: the condition of the reference optical path of coherent systems (e.g., changes in length, refractive index, transmission, dispersion, etc.); the condition of the sample optical path of the coherent system (e.g., changes in length, refractive index, transmission, dispersion, etc.); spectral misalignments or calibration problems in the Cl system detector; and the detection spectral instabilities in the Cl system light source. In the examples above, the corrective action(s) could be used to remedy the problem and allow the Cl system to continue functioning properly. However, in other cases, corrective actions may have already been applied and cannot be applied again (for example, maximizing the driving current of the light source), or a remedial action cannot be applied. In this case, the corrective action could provide notification to the process master and / or user to indicate that the system is no longer functioning properly and requires service or replacement. In some instances, this signal could be used to switch through the Cl system or spare system subcomponents. Monitoring trends in system calibration data could be collected and analyzed to build statistics on calibration stability and to achieve probabilistic failure mode and effects analysis (FMEA) data. For example, in laser keyhole welding, keyhole alignment calibration data could be used to determine alignment stability for a specific laser welding process. The effects of small changes in alignment on Cl system measurement quality could be characterized and used to determine the desired frequency of recalibration. Welding processes that are very sensitive to keyhole misalignment may involve more frequent recalibration. Similarly, welding processes that are very sensitive to keyhole misalignment are often more unstable processes. In this case, keyhole alignment calibration data could be used as a variable to indicate the stability of the overall welding process and could be used as a determination of process quality and the need for further optimization. When the Cl system determines that a specific recalibration is desired or that the calibration is no longer accurate, it may automatically perform the calibration routine, or may provide an indication to the cell or user that this procedure should be performed to the operation continues. Machine readable code recognition In many industries, it is useful to incorporate part identification markers, such as barcodes or QR codes, on the surfaces of products, components, and subcomponents. These identification markers could be useful for inventory tracking, product end-use tracking, provenance, and security markings. In some applications, a Cl system could be used for this identification marker scan. Calibration of the Cl system could be used to achieve appropriate measurement beam scanning strategies and measurement processing algorithms (or configurations) to reliably recognize the identification marker. Calibration could be used, for example, to accommodate different material backgrounds, ID marker colors, ID marker heights / depths, ID marker locations, and ID marker sizes. In the case where these markings were part of a quality control system, the Cl system would be able to capture the marking data and correlate it with other Cl system measurements taken before, during and after the marking was measured. A Cl system could also be used as part of the generation process for these identification markers. For example, the Cl system could be used to measure a marker and determine if it is of sufficient depth / height or of sufficient discoloration. The outputs of the Cl system could be fed back during the identification marker processing stage to modify the marking process. A common embodiment of this process is in the context of laser-generated identification markers (e.g., laser marking or laser scribing processes). The laser that marks the workpiece could be the same laser that performs laser processing of the workpiece. Marking could occur in the context of the laser processing environment or could be performed before or after the process itself. In some embodiments, a Cl system could be used as the identification marker reader. This could be beneficial to make some identification marks invisible to traditional readers (e.g., barcode readers, camera, LED scanners). These marks could be used, for example, to obscure product identifiers for security or aesthetic purposes. A Cl system could be used to guide the laser process in generating these marks and to provide feedback on the quality of the generation process. These marks could be generated by marking features or configurations on the surface of a material that primarily lead by themselves to the detection of Cl measurement (e.g., submicron configurations). For optically transparent or semi-transparent materials (in the Cl measurement beam or process beam colors), these configurations could be marked below the surface of the material. Subsurface features or configurations could be beneficial for marking plastics, glass, or semi-precious and precious stones. When reading these configurations, the Cl system would optionally calibrate the tilt of the part presentation and / or the optical path length distortion of the optical medium that passed through the Cl system's measurement beam ( (for example, lenses, air, water, oil, etc.). In one embodiment, a pulsed laser or stamp is used to very precisely structure a code, 3D QR barcode in relief on the surface of a workpiece, although the height variation between the negative and positive parts of the pattern is very small (10 um or less, or 50 um or less) and the transitions are so gradual that they cannot be read by conventional readers or perhaps even identified by sight. If sufficient control of the gravure / embossing system were possible, then it might be possible to encode multiple levels of value at each cross-sectional location of the 3D QR code or barcode, thereby greatly increasing the density of data that could be produced. per unit surface area on the workpiece. Optionally, this code could be coated to protect it from scratching or other damage. This coating could be opaque to visible light (although transparent to the Cl system) to make visual identification even more difficult. The clear difficulty of producing these configurations would make them useful for anti-counterfeiting or tampering applications. While the principles of the invention have been described herein, it will be understood by those skilled in the art that this description is made only by way of example and not as a limitation as to the scope of the invention. Other embodiments are contemplated within the scope of the present invention in addition to the example embodiments shown and described herein. Modifications and substitutions by a person of ordinary skill in the art are considered to be within the scope of the present invention, which will not be limited except by the following claims.

Claims

1. A system comprising: a material processing system including a processing beam source for generating a processing beam and a processing beam head for delivering the processing beam to a target; a coherence imaging (Cl) measurement system including a coherence imaging (Cl) core unit for generating a measurement beam and an Cl scanning module for delivering the measurement beam to the target, wherein the Cl measurement system produces a Cl measurement output;and at least one controller configured to receive the Cl measurement output from the Cl core unit to monitor and / or control the material processing system, wherein the controller is also configured to receive a calibration measurement output and to control the Cl measurement system based, at least in part, on the calibration measurement output, wherein the controller is configured to control the Cl measurement system to modify future measurements made by the Cl measurement system for the alignment of the Cl measurement system and the processing beam.

2. The system according to claim 1, wherein the measuring system Cl produces the calibration measurement output and wherein an interferometry output of the measuring system Cl is used as the contrast mechanism to produce the calibration measurement output of the measuring system Cl.

3. The system according to claim 1, wherein the measuring system Cl produces the calibration measurement output and wherein the process radiation produced by the processing beam is used as the contrast mechanism to produce the calibration output of the measuring system Cl.

4. The system according to claim 1, further comprising a 2D in-line camera coupled with the processing head and wherein the 2D in-line camera generates image data used to produce the calibration measurement output.

5. The system according to claim 4, wherein the 2D in-line camera shares an optical path with the Cl measuring system and wherein the back-reflected light is split between the 2D in-line camera and the Cl measuring system.

6. The system according to claim 1, further comprising a double-coated fiber coupled with the Cl core unit and with a photodetector, wherein the double-coated fiber is configured to transmit the process radiation to the photodetector and to transmit the light from the measurement beam to the Cl core unit.

7. The system according to claim 6, wherein the calibration measurement output is produced by the photodetector.

8. The system according to claim 1, further comprising a 2D camera positioned close to the target and wherein the 2D camera generates image data used to produce the calibration measurement output.

9. The system according to claim 1, wherein the material processing system includes a laser processing system.

10. The system according to claim 9, wherein the laser processing system includes a laser having a substantially unique spatial output mode with a square value M less than 2.

0.

11. The system according to claim 1, wherein the Cl measurement system includes an online coherence imaging (ICI) system.

12. A method for calibrating a coherence (Cl) imaging measurement system, comprising: providing a material processing system configured to generate and deliver a processing beam to a target; providing a coherence (Cl) imaging measurement system configured to generate and deliver a measurement beam to the target and configured to provide an Cl measurement system output to control and / or monitor the material processing system; obtaining a calibration measurement output from the Cl measurement system and / or an auxiliary sensor; and automatically controlling the Cl measurement system based, at least in part, on the calibration measurement output, wherein the Cl measurement system is controlled to modify future measurements made by the Cl measurement system for alignment of the Cl measurement system and the processing beam.

13. The method according to claim 12, wherein the calibration measurement output is provided by the measurement system Cl using an interferometry output of the measurement system Cl as a contrast mechanism.

14. The method according to claim 13, wherein obtaining the calibration measurement output comprises: producing, at least temporarily, a physical modification in the target using the processing beam; obtaining a measurement of the physical modification using the measuring system Cl; and obtaining the calibration measurement output of the measuring system Cl such that the physical modification corresponds to a position of the processing beam.

15. The method according to claim 14, wherein obtaining the measurement Cl includes scanning the measurement beam at the target near the physical modification in a scanning pattern.

16. The method according to claim 12, wherein the calibration measurement output is provided by the Cl measurement system using a process emission produced by the processing beam as a contrast mechanism.

17. The method according to claim 16, wherein obtaining the calibration measurement output comprises: reducing a light source of system Cl to at least an imperceptible level; directing the processing beam towards the target; receiving the process radiation from the target in the measurement system Cl when the processing beam is directed at the target; and obtaining the calibration measurement output from the measurement system Cl that detects the process radiation.

18. The method according to claim 17, wherein the measuring system Cl detects the process radiation while the measuring system Cl is scanning the target.

19. The method according to claim 17, wherein the direction of the processing beam includes the movement of the processing beam in the target and the intensity of the detected processing radiation is used to determine a position of the processing beam.

20. The method according to claim 12, wherein the calibration measurement output is provided as a function of image data from a 2D online camera coupled with the material processing system.

21. The method according to claim 20, wherein obtaining the calibration measurement output comprises: directing at least one of the processing beam and the measuring beam towards the target; detecting, using the 2D in-line camera, at least one of the process radiation caused by the processing beam and the back-reflected light from the measuring beam; and obtaining the calibration measurement output from the image data generated by the 2D in-line camera that detects at least one of the process radiation and the back-reflected light from the measuring beam.

22. The method according to claim 12, wherein obtaining the calibration measurement output comprises directing the processing beam towards the target while at least pulsing the processing beam.

23. The method according to claim 12, wherein the calibration measurement output is provided by a photodetector coupled with a double-coated fiber used in the Cl measurement system.

24. The method according to claim 23, wherein obtaining the calibration measurement output comprises: directing at least one of the processing beam and the measurement beam towards the target; transmitting, using the double-coated fiber, the process radiation to the photodetector and the back-reflected light from the measurement beam to the measurement system Cl; detecting the process radiation using the photodetector; and obtaining the calibration measurement output from the photodetector that detects the process radiation.

25. The method according to claim 12 wherein the calibration measurement output is provided by a 2D camera positioned close to the target.

26. The method according to claim 25 wherein obtaining the calibration measurement output comprises: directing at least one of the processing beam and the measuring beam towards the target; detecting, using the 2D camera, at least one of the process radiation caused by the processing beam and the back-reflected light from the measuring beam; and obtaining the calibration measurement output from the image data generated by the 2D camera that detects at least one of the process radiation and the back-reflected light from the measuring beam.

27. The method according to claim 12, wherein the modification of future measurements made by the measurement system Cl includes at least one of the modification of the spatial positioning during measurement acquisition, the modification of the temporal synchronization during measurement acquisition, and the modification of the measurement algorithms.

28. The method according to claim 12, wherein the modification of future measurements made by the measuring system Cl includes modifications to correct optical distortions introduced by a beam delivery system in the material processing system and / or in the measuring system Cl.

29. The method according to claim 28, wherein the modification of future measurements made by the measuring system Cl includes the modifications wherein the optical distortions include at least one of: optical path length change, chromatic aberration, defocus, field curvature, image distortion, spherical aberration, coma, and astigmatism.

30. The method according to claim 12, wherein the modification of future measurements made by the measuring system Cl includes modifications to correct mechanical distortions of the material processing system and / or the measuring system Cl.

31. The method according to claim 30, wherein the mechanical distortions include at least one of: vibrations, adjustment, torsion, extension, compression, translation, and rotation.

32. The method according to claim 12, wherein the modification of future measurements made by the measuring system Cl includes the modifications to correct the process timing problems selected from the group consisting of the process timing problems including at least one of: motion control path timing, processing laser energy profile timing, workpiece distortions, process inputs, shielding gas, cover gas, process environment, process feed material, process sacrificial material, and process repair.

33. The method according to claim 12, wherein the modification of future measurements t / FRQn / zznz / q / YiAi performed by the measurement system Cl includes the modifications to correct for changes to the phase change region.

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