Colorimetric range sensor system and method with spherical calibration object

Abstract

A method provides distance calibration data to a colorimetric range sensor system having a colorimetric range sensor optical pen configured to focus different wavelengths at different distances along a distance measurement axis. The colorimetric range sensor optical pen is arranged in a certain relationship relative to a spherical calibration object having a nominal spherical calibration surface. The relative movement of the colorimetric range sensor optical pen with respect to the nominal spherical calibration surface is controlled to perform a helical scan of a portion of the nominal spherical calibration surface. Distance indication data is determined to correspond to the distance between the colorimetric range sensor optical pen and a surface point on the nominal spherical calibration surface when the helical scan is performed. Distance calibration data for the colorimetric range sensor system is determined based on the distance indication data.

Description

Technical Field

[0001] This disclosure generally relates to precision measuring instruments, and more specifically to, for example, colorimetric range sensors that can be used with a measuring machine to determine measured values ​​of a workpiece. Background Technology

[0002] The use of chromatic confocal techniques in optical range sensors (e.g., sensors containing height, distance, etc.) is known. As described in U.S. Patent No. 7,876,456 (′456 Patent), which is incorporated herein by reference in its entirety, a broadband light source can be focused using an optical element with axial chromatic aberration—also known as axial or longitudinal dispersion—such that the axial distance to the focal point varies with wavelength. Therefore, only one wavelength will be precisely focused on the surface, and the surface height, or distance relative to the focusing element, determines which wavelength is optimally focused. After reflection from the surface, the light is refocused onto a small detector aperture, such as a pinhole or the end of a fiber optic cable. As the light reflects from the surface and travels backward through the optical system to the input / output fiber, only the wavelength that is well focused on the surface is well focused on the aperture. All other wavelengths are poorly focused on the aperture and therefore do not couple much power into the fiber. Therefore, for the light returning through the fiber, the signal level corresponding to the wavelength at the surface height (i.e., distance) from the surface will be the highest. Spectrometer-type detectors measure the signal level at each wavelength in order to determine the surface height (e.g., wavelengths that are well focused on the surface typically form the highest peak in the entire detector signal).

[0003] Some manufacturers refer to practical and compact colorimetric range sensing (CRS) systems, which operate as described above and are suitable for use in industrial environments, as colorimetric point sensors (CPS) or colorimetric line sensors, etc. The compact dispersive optics used with such systems are called "optical pens" or simply "pens." The optical pen is connected to the electronics of the colorimetric range sensor system via optical fiber. The electronics contain a light source that transmits light through the optical fiber to output from the optical pen and also provide a spectrometer that detects and analyzes the returned light. The returned light forms a wavelength dispersion intensity distribution received by the detector array of the spectrometer. Pixel data corresponding to the wavelength dispersion intensity distribution is analyzed to determine "dominant wavelength position coordinates" (e.g., corresponding to wavelengths that are well focused on the surface), indicated by the peaks or centroids of the intensity distribution. The resulting pixel coordinates of the peaks and / or centroids are used, along with a lookup table, to determine the distance to the surface. These pixel coordinates can be determined at sub-pixel resolution and may be referred to as "distance indicator coordinates" or "distance indicator pixel coordinates."

[0004] A significant issue with colorimetric range sensors is the stability of their components relative to their calibration. Based on distance calibration data that correlates a known measurement distance with the position coordinates of the dominant wavelength obtained along the detector array, colorimetric range sensors offer extremely high resolution and accuracy (e.g., sub-micron resolution and accuracy). At the level of resolution and accuracy provided by a colorimetric range sensor, component behavior inevitably drifts relative to the behavior provided at factory calibration, resulting in measurement errors. Known calibration methods typically require equipment and / or expertise that the end user cannot provide (e.g., especially when the colorimetric range sensor is attached to a measuring machine). Therefore, if measurement accuracy decreases, or if the user wishes to replace specific components of the colorimetric range sensor (e.g., an optical pen), the entire device may need to be sent back to the factory for recalibration. Additionally, in some implementations, it may be desirable to be able to mount or maintain the colorimetric range sensor on a measuring machine without prior factory calibration (e.g., for faster delivery, reduced setup costs, etc.). Regarding such issues, providing improved, simplified, and / or more reliable colorimetric range sensor calibration (e.g., for initial calibration and / or recalibration, etc.) (e.g., when attached to a measuring machine, etc.) would be desirable. Summary of the Invention

[0005] The summary is provided to introduce, in a simplified form, the selection of concepts further described in the detailed embodiments below. This summary is not intended to identify key features of the claimed subject matter, nor is it intended to help determine the scope of the claimed subject matter.

[0006] A method is provided for determining distance calibration data for a colorimetric range sensor system having a colorimetric range sensor optical pen coupled to a measuring machine. The colorimetric range sensor optical pen is configured to focus different wavelengths at different distances from the surface to be measured. The colorimetric range sensor optical pen is arranged in a certain relationship relative to a spherical calibration object having a nominal spherical calibration surface. The measuring machine is controlled to achieve relative movement of the colorimetric range sensor optical pen about the nominal spherical calibration surface. The relative movement of the colorimetric range sensor optical pen is helical to perform a helical scan on a portion of the nominal spherical calibration surface, wherein distance indication data is determined to correspond to the distance between the colorimetric range sensor optical pen and a surface point on the nominal spherical calibration surface during the helical scan. Distance calibration data for the colorimetric range sensor system is determined based on the distance indication data.

[0007] In some embodiments, a system is provided that includes a measuring machine, a colorimetric range sensor system, and a spherical calibration object. The measuring machine includes a motion controller. The system is configured to utilize the motion controller to achieve relative movement of the colorimetric range sensor optical pen about a nominal spherical calibration surface. A helical scan of the nominal spherical calibration surface is performed to determine distance indication data used to determine distance calibration data.

[0008] In some embodiments, the colorimetric range sensor system includes a colorimetric range sensor optical pen, an illumination source, a wavelength detector, and a processing unit. The illumination source is configured to generate multi-wavelength input light having an input spectral distribution input to the colorimetric range sensor optical pen. The wavelength detector includes a plurality of pixels having corresponding pixel positions distributed along a wavelength measurement axis of the wavelength detector. The colorimetric range sensor system is configured such that when the colorimetric range sensor optical pen is operably positioned relative to a surface to perform a measurement operation, the colorimetric range sensor optical pen inputs the input spectral distribution and outputs the corresponding radiation to the surface, and receives reflected radiation from the surface and outputs the reflected radiation to the wavelength detector. The processing unit is configured to determine distance indication data generated by the relative movement of the colorimetric range sensor optical pen about a nominal spherical calibration surface. The relative movement of the colorimetric range sensor optical pen is helical to perform a helical scan of a portion of the nominal spherical calibration surface, wherein the distance indication data is determined to correspond to the distance between the colorimetric range sensor optical pen and a surface point on the nominal spherical calibration surface during the helical scan. The distance calibration data is determined based on the distance indication data. Attached Figure Description

[0009] The foregoing aspects and many accompanying advantages of the invention will become more readily and better understood when taken in conjunction with the accompanying drawings and the following detailed description, wherein:

[0010] Figure 1 This is a block diagram of an exemplary color gamut sensor (CRS) system that includes an optical pen;

[0011] Figure 2 This is a graph of the system noise (bias) distribution from the CRS system, showing the wavelength-dependent voltage offset signal level of the pixels in the detector array when no measurement surface is present;

[0012] Figure 3 This is an intensity distribution map from the CRS system, showing the effective wavelength peaks generated by the wavelengths reflected from the surface, where the pixel positions of the peaks correspond to the measured distances to the surface;

[0013] Figure 4AIt is the first representation of the CRS distance calibration data, which correlates the distance indicator pixel coordinates with the known measured distance to the measured workpiece surface;

[0014] Figure 4B It is a second representation of CRS distance calibration data, including an example CRS distance calibration lookup table, which references the distance indication coordinates (DIC) to the corresponding measured distance in the CRS system;

[0015] Figure 5 This is a block diagram of a first exemplary embodiment of a measurement system, which includes a measuring machine (e.g., a machine vision inspection system) for measuring workpieces in conjunction with a CRS system;

[0016] Figure 6 This is a block diagram of a second exemplary embodiment of a measurement system, which includes a measuring machine (e.g., a coordinate measuring machine) combined with a CRS system for measuring a workpiece;

[0017] Figure 7 An example of a calibration object in the form of a spherical calibration object is shown;

[0018] Figure 8 A spiral scan is shown performed on the top surface of a spherical calibration object;

[0019] Figure 9A An example measurement of the distance to a surface point on a spherical calibration object is shown, where the center point of the spiral scan is precisely aligned with the top center of the spherical calibration object;

[0020] Figure 9B An example measurement of the distance to a surface point on a spherical calibration object is shown, where the center point of the spiral scan is offset relative to the top center of the spherical calibration object;

[0021] Figure 10 Shows distance indicator coordinates versus radial position curves, including data from... Figure 9A and 9B The value;

[0022] Figure 11 It is by Figures 8 to 10 The diagram shows a representation of the CRS distance calibration data determined by the process; and

[0023] Figure 12 This is a flowchart illustrating an exemplary embodiment of a routine for determining distance calibration data for a CRS system. Detailed Implementation

[0024] Figure 1This is a block diagram of an exemplary colorimetric range sensor (CRS) system 100 of a first type based on the operating principle desired for use with a measuring machine. The CRS system 100 shares certain similarities with systems described in U.S. Patent Nos. 7,876,456 and 7,990,522 (referred to as '456' and '522' patents, respectively), which are hereby incorporated herein by reference in their entirety. Figure 1 As shown, the CRS system 100 includes an optical pen 120, an electronic component 160, and a user interface component 171. It should be understood that... Figure 1 The CRS system 100 shown is a chromaticity point sensor (CPS) system (i.e., where the optical pen 120 is a chromaticity point sensor), which in some cases can measure a single measurement point at a time. However, in various embodiments, alternative types of chromaticity range sensor systems, such as chromaticity line sensors, can be utilized.

[0025] The optical pen 120 includes a fiber optic connector 109, a housing 131 (e.g., an assembly tube), and an optical component portion 150. The fiber optic connector 109 is attached to an end of the housing 131. In various embodiments, the fiber optic connector 109 may be oriented at an angle relative to the housing 131. The fiber optic connector 109 receives input / output optical fibers (not shown in detail) via an optical fiber cable 112 surrounding it. The input / output optical fibers output source light through a fiber optic aperture 195 and receive reflected measurement signal light through the same aperture.

[0026] In operation, broadband (e.g., white) source light emitted from the fiber end through fiber aperture 195 is focused by optical component portion 150, which includes one or more lenses providing axial dispersion such that the focal point along the optical axis OA is located at different distances depending on the wavelength of the light, as is known for chromatic confocal sensor systems. The source light forms a measurement beam 196 containing wavelengths focused on a surface 190 (e.g., the surface of a workpiece or calibration object, etc.) at position Z relative to optical pen 120. After reflection from surface 190, the reflected light is refocused by optical component portion 150 onto fiber aperture 195. The effective source light and reflected light are defined by limiting rays LR1 and LR2. Due to axial dispersion, only one wavelength will have a front focal size FF matching the measurement distance (e.g., measurement distance Z) from optical pen 120 (e.g., from a reference position RP fixed relative to optical pen 120) to a position on workpiece surface 190. The optical pen is configured such that the wavelength optimally focused at surface 190 is also the wavelength of the reflected light optimally focused at fiber aperture 195. Fiber aperture 195 spatially filters the reflected light, allowing the predominantly optimally focused wavelength to pass through and enter the core of fiber optic cable 112. As described in more detail below and in the incorporated references, fiber optic cable 112 directs the reflected signal light to wavelength detector 162, which determines the wavelength with the predominant intensity corresponding to the measurement distance to surface 190.

[0027] Electronic component 160 includes fiber optic coupler 161, wavelength detector 162, light source 164, signal processor 166, and memory component 168. In various embodiments, wavelength detector 162 includes a spectrometer or spectrometer apparatus, wherein a dispersive optics component (e.g., a grating) receives reflected light via fiber optic cable 112 and transmits the resulting spectral intensity profile to detector array 163. Wavelength detector 162 may also include correlation signal processing (e.g., provided by signal processor 166 in some embodiments) that removes or compensates for certain detector correlation error components from the profile data. Therefore, in some embodiments, certain aspects of wavelength detector 162 and signal processor 166 may be combined and / or indistinguishable. In various embodiments, signal processor 166 and / or wavelength detector 162 and / or other signal processors, computing systems, etc., used for correlation processing may be referred to as the processing portion of CRS system 100.

[0028] A white light source 164, controlled by a signal processor 166, is connected to an optical fiber cable 112 via an optical coupler 161 (e.g., a 2x1 optical coupler). As described above, light passes through an optical pen 120, creating longitudinal chromatic aberration that causes its focal length to vary with the wavelength of the light. The wavelength of the light most efficiently transmitted back through the optical fiber is the wavelength focused at position Z on surface 190. The reflected wavelength-dependent light intensity then passes again through the optical fiber coupler 161, such that approximately 50% of the light is directed to a wavelength detector 162, which receives the spectral intensity distribution along the wavelength measurement axis of the detector array 163 distributed across the pixel array and is used to provide corresponding distribution data, as described in more detail in the incorporated references.

[0029] In simple terms, the subpixel resolution distance indicator coordinates (DIC) of the distributed data (see, for example, [reference needed]). Figure 3 The measured distance Z, calculated by the signal processor 166 and indicated by the DIC (in subpixels) to the position on the surface 190 (in micrometers) via a distance calibration lookup table, is stored in the calibration section 169 of the memory section 168 (e.g., hereinafter regarding...). Figure 4A , 4B (As described in 11). According to previously known methods, DIC can be determined using various techniques (e.g., based on the centroid of the intensity distribution data contained in the peak region). In various embodiments, the distribution data can be used to determine DIC with sub-pixel resolution, as will be described in more detail below.

[0030] The optical pen 120 typically has a measurement range R defined by a minimum range distance ZMIN and a maximum range distance ZMAX. In some exemplary cases of known optical pens, the measurement range R can be approximately one-tenth of the nominal clearance or working distance from the tip of the pen (e.g., in the range of tens of micrometers to a few millimeters). It should be understood that in some embodiments, the electronic component 160 can be positioned remotely from the optical pen 120. For example, it is known that using a custom bracket will... Figure 1 An optical pen, similar to the optical pen 120 shown, is mounted on the CMM and an optical fiber, similar to the optical fiber cable 112, is guided along a temporary path outside the CMM component to a remote positioning electronics component, similar to the electronics component 160.

[0031] In various implementation schemes (e.g., as will be discussed below) Figure 6In some embodiments (described in more detail), a set of components in the light source and wavelength detector section 160A (e.g., including wavelength detector 162 and light source 164) may be included within the CRS optical probe assembly. If desired, a set of components in the measurement signal processing and control circuitry 160B (e.g., including signal processor 166 and memory section 168) may be located remotely outside the CRS optical probe assembly (e.g., to maintain low probe weight and compact probe size).

[0032] As in Figure 1 As shown, the user interface portion 171 is coupled to the electronics portion 160 and provides a user interface configured to receive user input for operating the CRS system 100, such as user commands to select various operating parameters, via any suitable component such as a keyboard, touch sensor, or mouse. In an exemplary embodiment, the user interface portion 171 may include one or more operating mode selection elements (e.g., user-selectable buttons) that a user can operate to select one of a plurality of operating modes of the CRS system 100 (e.g., measurement mode, calibration mode, etc.). The user interface portion 171 is also configured to display information on a screen, such as one or more distances successfully determined / measured by the CRS system 100.

[0033] Figure 1 It includes orthogonal XYZ coordinate axes as a reference frame. The Z direction is defined as parallel to the optical axis (OA) of the optical pen 120, which is the distance measurement axis. For example... Figure 1 As shown, during operation, the surface 190 (e.g., the workpiece to be measured or the object to be calibrated) is positioned / placed along the optical axis OA.

[0034] Figure 2 The following description outlines some known background signal processing and / or calibration operations. Figure 2 Figure 200 shows the system noise (bias) spectrum from the CRS system, illustrating the voltage offset signal level Voffset(p) of the pixels in detector array 163 when there is no measurement surface within the nominal total measurement range of the CRS system. In this case, there is no intentionally reflected light, and therefore no significant or dominant wavelength peaks in the resulting intensity spectrum. For each of the 1,024 pixels along the wavelength measurement axis of detector array 163, the voltage offset signal Voffset(p) is plotted in normalized volts. "Normalized volts" assigns a value of 1.0 to the saturation voltage of detector array 163. The voltage offset signal Voffset(p) comprises a relatively consistent bias signal level Vbias across the detector array and a background signal component Vback(p) that appears to vary across the detector array.

[0035] The variable background signal Vback(p) represents, for example, background light from wavelength-dependent stray reflections in the chromaticity point sensor and signals such as dark currents attributed to various pixels p. In various embodiments, it is advantageous to store the signal component Vback(p) (or a signal exhibiting the same variation, such as a voltage offset signal Voffset(p)) for calibration or compensation of the pixel array of detector array 163, and for continuously compensating all subsequent distribution data signals from each pixel p (e.g., by subtraction). Therefore, it should be understood that in various embodiments, it is assumed that the background signal component Vback(p) is compensated in a known manner, and thus further explicit consideration or description regarding the various intensity distributions or signal processing operations of the invention described below is unnecessary.

[0036] The following are Figure 3 , 4A The description in 4B outlines certain signal processing operations that determine distance indication coordinates (DIC) with subpixel resolution based on the effective wavelength peaks generated in the wavelength dispersion intensity distribution of the CRS system, and determine the measured distance to the surface (e.g., in micrometers) based on the determined DIC. Some previously known operations outlined herein are described in more detail in the '456 patent, while some alternative operations disclosed herein are described below regarding... Figures 5 to 12 A more detailed description is provided. The purpose of this manual is to provide information suitable for a comprehensive understanding of certain CRS measurement operations described herein.

[0037] Figure 3 The wavelength dispersion intensity distribution map 300 from the CRS system shows the effective wavelength peaks 302 generated by a subset of the measured distribution signal MS(p), indicating wavelengths focused on (e.g., a calibration object or workpiece, etc.) and reflected by said surface. As previously mentioned, as part of standard operation of the CRS system, the signal level will be highest for wavelengths corresponding to the surface height or distance to the surface, where wavelengths well focused on said surface typically form the highest peak in the entire detector signal. Figure 3 In the example, Figure 300 includes wavelength peaks 302 corresponding to the measured surface. Each measurement distribution signal in the measurement distribution signal MS(p) has a signal level (in normalized volts) associated with each pixel p of the detector array (e.g., detector array 163). The wavelength peaks 302 have sufficient height (good signal-to-noise ratio), are relatively symmetrical, and allow for good estimation of the peak position or measurement distance indication coordinates (DIC) 304 along the wavelength measurement axis of the detector array. Figure 3The bias signal level MVbias (in normalized volts), peak pixel coordinates (ppc), and data threshold MVthreshold, which defines the lower limit of the distance indication subset of the measurement distribution signal MS(p) forming the wavelength peak 302, are also shown. All values ​​(e.g., including the “MV” value) are in normalized volts.

[0038] In short, in one embodiment, the measurement operation for determining distance indication coordinates (DIC) (in pixels) and determining the corresponding measurement distance (in micrometers) based on the determined DIC may include the following:

[0039] • Locate the target surface along the optical axis OA and capture the wavelength dispersion intensity distribution shown in Figure 300.

[0040] • Determine the peak pixel coordinates (ppc), where ppc is the pixel with the highest signal.

[0041] • Determine the measurement bias signal level MVbias at a given sampling rate.

[0042] • Determine the data threshold MVthreshold (e.g., as a percentage of the peak height).

[0043] • Determine the distance indication coordinates (DIC) with subpixel resolution based on a subset of the measurement distribution signal MS(p) that forms a wavelength peak with a value greater than MVthreshold.

[0044] • By comparing the DIC with the stored distance calibration data (e.g., Figure 4A or Figure 11 Distance calibration curve or Figure 4B The distance to be measured is determined by the corresponding distance in the lookup table (e.g., in the context of distance measurement).

[0045] In the aforementioned operation, DIC can be determined using sub-pixel resolution based on a distance indication subset of the measured distribution signal MS(p) above the data threshold MVthreshold. According to previously known methods, DIC can be determined as the centroid X of the distance indication subset of the signal MS(p). C The subpixel resolution coordinates. For example, for a detector with 1024 pixels (i.e., each pixel has a corresponding pixel number (p) from 1 to 1024), the centroid X C It can be determined based on the following:

[0046]

[0047] in,

[0048]

[0049] In a specific example, n = 2 in Equation 1. It should be understood that Equation 2 restricts the signal MS(p) used in the centroid calculation to a subset of distance indicators.

[0050] Figure 4A Figure 400A is the first representation of the CRS measurement distance calibration data 410A, which compares the distance indication coordinates (DIC) with subpixel resolution with the known measurement distance (ZOUT) in micrometers along the optical axis (OA) of the CRS system (e.g., stored in...). Figure 1 (Related to calibration section 169). It should be understood that... Figure 4A The specific values ​​are intended to be illustrative only and may not correspond to specific values ​​indicated in other examples (e.g., regarding...). Figures 1 to 3 Some values ​​described and / or as will be described in more detail below. Figure 4B The specific table values ​​are not provided, but it should be understood that these concepts are similar. Figure 4A The example shown refers to an optical element (e.g., an optical pen) with a nominal total measurement range (MR) of approximately 300 micrometers, which corresponds to a DIC ranging from approximately 150 to 490 pixels. However, if necessary, the CRS system can be calibrated in a larger pixel range and / or different portions of the detector array 163. Although the distance calibration data 410A appears to form a smooth curve, it should be understood that in some cases, for a typical CRS system, and specifically for an economical CRS system, the distance calibration data and / or output spectral distribution data may exhibit certain short-range variations / irregularities (e.g., as described in part in the '456 patent).

[0051] An exemplary laboratory calibration method (e.g., applicable to factory calibration, etc.) for determining CRS measurement distance calibration data 410A and / or 410B employs a mirror that moves along the optical axis OA (e.g., in one example implementation, it could be...). Figure 1 The surface of the mirror (190°) is used. The displacement of the mirror relative to the optical pen along the optical axis OA can be controlled (e.g., by a stepper motor, etc.) to calibrate the measurement distance in approximately equal steps (e.g., 0.1 or 0.2 micrometer steps). For each step, the actual mirror position or displacement is obtained using a reference standard such as an interferometer. For each actual mirror position, the calibration distance indication coordinates of the CRS system are determined based on the corresponding intensity distribution data provided by the CRS detector. The calibration distance indication coordinates and the corresponding actual position are then recorded to provide distance calibration data 410A and / or 410B. While such techniques can be used to provide accurate distance calibration data (e.g., as part of a factory calibration process), certain alternative techniques disclosed herein (e.g., will be discussed below) are also available. Figures 7 to 12(As described in more detail) It can also be used, or alternatively, in certain embodiments, and such alternative techniques may have certain advantages for these embodiments.

[0052] After determining the distance calibration data, during subsequent measurement operations, in order to determine the distance to the workpiece surface (e.g., Figure 1 The workpiece surface is positioned along the optical axis OA of the CRS optical pen by measuring the distance from the surface (190°). Based on the measurement DIC determined from the intensity distribution data provided by the CRS detector, the measurement distance indication coordinates of the CRS are determined. Then, the CRS measurement distance Z corresponding to that specific measurement DIC is determined using distance calibration data (e.g., distance calibration data 410A, 410B, or 1110).

[0053] Figure 4B Figure 400B is a second representation 410B of CRS distance calibration data, including a CRS distance calibration lookup table used to reference distance indication coordinates to (e.g., stored in...) Figure 1 The measurement distance of the chromaticity point sensor in calibration section 169. As mentioned above, it should be understood that... Figure 4B The table values ​​are intended to be illustrative only and may not correspond to specific values ​​indicated in other examples, such as... Figure 4A Those examples are examples of this, but for other examples it should be understood that the concepts are similar. Generally, it should be understood that the same set of distance calibration data can be represented as a curve (e.g., Figure 4A and 11 (as shown) or a table (e.g., Figure 4B (as shown), and the distance calibration data used to form one such representation can be similarly used to form another type of representation and / or other representations.

[0054] exist Figure 4B In the left column, the calibration DIC entries cover pixel coordinates from 1 to 1,024, in increments of 0.1 pixel steps, and in the right column, the corresponding measurement distance (in micrometers) (ZOUT) is entered. During operation, the measurement DIC calculated by the CRS system references a stored calibration lookup table to determine the corresponding measurement distance (in micrometers). If the measurement DIC falls between adjacent calibration DIC values, the measurement distance can be determined, for example, by interpolation. Figure 4B In the examples, some specific example values ​​are shown for a small range of DICs with pixel positions of approximately 104, 604, and 990, where the corresponding measurement distances are in the range of approximately 37 micrometers, 381 micrometers, and 486 micrometers.

[0055] In operation (e.g., for example, such as...) Figure 1(As shown in the measurement distance to surface 190), the optical pen 120 is connected to the CRS electronics section 160 and operably positioned relative to surface 190 to perform measurement operations. The measurement operations include: the optical pen 120 inputting an input spectral distribution from illumination source 164 and outputting the corresponding radiation to surface 190; and receiving reflected radiation from surface 190 and outputting the reflected radiation to provide an output spectral distribution to CRS wavelength detector 162, which then provides output spectral distribution data. The output spectral distribution includes distance-dependent distribution components and distance-independent distribution components. The distance-dependent distribution components have wavelength peaks (e.g., [missing information]). Figure 3 The peak value 302 in the wavelength indicates the measurement distance (e.g., measurement distance Z) from the optical pen 120 to the surface 190. As described above, the measurement DIC determined by the CRS system based on centroid calculation is referenced to the stored distance calibration data (e.g., peak value 302), where the wavelength peak value indicates the measurement distance (e.g., measurement distance Z) from the optical pen 120 to the surface 190. Figure 4A , 4B Or 11) to determine the measurement distance corresponding to the measured DIC (e.g., the measurement distance Z, which is the value ZOUT). If the measured DIC falls between adjacent calibration DIC values, the measurement distance corresponding to the measured DIC can be determined by interpolation (e.g., between the measurement distances corresponding to adjacent calibration DIC values).

[0056] Figure 5 This is a block diagram of a first exemplary embodiment of a measurement system 500, which includes a measuring machine 501 (e.g., a machine vision inspection system) for measuring workpieces in conjunction with a CRS system 100'. In the various figures herein, unless otherwise indicated by the specification or context, reference numerals with similar suffixes (e.g., reference numerals 1XX and 1XX' or 5XX with the suffix XX) generally refer to substantially similar elements, such that those skilled in the art can generally understand the operation of element 1XX' or 5XX based on similar prior descriptions of similar element 1XX, even with limited description. However, it should be understood that despite this analogy, various elements may have different embodiments in different implementations, as will be apparent to those skilled in the art, and are not limited to being identical.

[0057] As is known in the art, machine vision inspection systems (“vision systems”) can be used to obtain precise dimensional measurements of an object being inspected and to inspect various other object features. Such systems may include a computer and user interface 506, a camera (not shown), an optical imaging system 534, and a movable precision stage 572, enabling the camera to scan features of the workpiece being inspected. Machine vision inspection systems having optical systems such as the optical imaging system 534 are described in U.S. Patents Nos. 7,454,053 and 8,085,295, which are incorporated herein by reference in their entirety. Various aspects of machine vision inspection systems and control systems are also described in more detail in U.S. Patent No. 7,324,682 (‘682 patent) and U.S. Patent Publication No. 20050031191 (‘191 publication), which are also incorporated herein by reference in their entirety. As described in '682 and '191 disclosures, a machine vision inspection system (MVIS) 501 may include a vision system controller 502, which is capable of recalling captured and stored workpiece inspection images, inspecting and analyzing workpiece features in such workpiece inspection images, and storing and / or outputting inspection results. Figure 5 Includes orthogonal XYZ coordinate axes of the machine coordinate system (MCS) used as a reference frame for MVIS 501. Figure 5 In the configuration, the Z-axis of the MCS is parallel to the Z-direction of the optical pen 120′, which is defined as the optical axis parallel to the optical pen 120′, which is the distance measurement axis of the optical pen 120′.

[0058] like Figure 5 As shown, the optical imaging system 534, including objective lens 570, has an optical axis OA2 and can be used to magnify and image the surface of a workpiece on stage 572. The optical imaging system 534 can obtain an image focus by moving along a Z-axis guide bearing 534a, and in various embodiments, can be moved by a motion mechanism 534b (e.g., a controllable motor that drives actuators to move the optical imaging system 534 along the Z-axis). In various embodiments, the motion mechanism 534b can be controlled by a motion controller 505 in a vision system controller 502. In various embodiments, the workpiece can be located in the field of view (FOV) of the optical imaging system 534 on the workpiece stage 572, which is movable along the X and Y axes on the guide bearing 572a. The workpiece stage 572 can be moved by the motion mechanism 572b (e.g., a controllable motor that drives actuators to move the workpiece stage 572 along the X and / or Y axes). In various embodiments, the motion mechanism 572b can be controlled by the motion controller 505.

[0059] The machine vision inspection system (MVIS) 501 may include a probe system 536, which may be mounted to or otherwise coupled to a turntable of the MVIS 501 via a suitable bracket (not shown) (forming an optical imaging system 534). The probe system 536 may be adapted to hold an optical pen 120' of the CRS system 100' for use in conjunction with various measurement and calibration functions, such as those described herein. In various embodiments, the optical pen 120' will be understood to include... Figure 1 The optical pen 120′ is a component similar to or identical to the optical pen 120′. The optical pen 120′ may be mechanically coupled to the probe head assembly 539, and the optical fiber 112′ connects the optical pen 120′ to the optical pen electronics portion 160′ of the CRS system 100′. In the illustrated embodiment, the optical pen electronics portion 160′ is part of the vision system controller 502. The MVIS 501 may include associated control software, which is similar to that obtained through QUICK, available from Mitutoyo America Corporation (MAC) in Aurora, Illinois. The control software available for the QV Apex series vision systems is roughly equivalent.

[0060] In this configuration, standard coordinate measuring machine (CMM) technology can be combined with standard machine vision techniques to utilize motion controller 505 to control the movement of probe system 536 and / or stage 572, so that the optical pen 120' with measurement beam 196' is automatically positioned relative to the surface to be measured. Alternatively, motion controller 505 can be used to move stage 572 and / or optical imaging system 534, enabling measurement and calibration functions (e.g., those described herein and in incorporated references). As will be described in more detail below, certain operations can be performed as part of a calibration method for obtaining distance calibration data of CRS system 100' containing optical pen 120', including measuring spherical calibration object 700 (e.g., see...). Figure 7 ).

[0061] like Figure 5As shown, the probe system 536 is movable along the Z-axis guide bearing 536a and can be moved by a motion mechanism 536b (e.g., a controllable motor that drives an actuator to move the probe system 536 along the Z-axis). In various embodiments, the motion mechanism 536b may be controlled by a motion controller 505. In various embodiments, the probe system 536 may be coupled to an optical imaging system 534 (e.g., coupled to a turntable containing the optical imaging system 534 via a suitable bracket) such that one or both of the Z-axis guide bearings 534a and / or 536a may be included and / or otherwise configured to allow the Z-axis movement of the optical imaging system 534 and the probe system 536 to be controlled by one or both of the motion mechanisms 534b or 536b. In some embodiments, the turntable of the MVIS 501 and the optical pen 120' of the CRS system 100' move one after the other along the Z-axis. In various embodiments, the Z-measurement ranges of the optical imaging system 534 and the optical pen 120′ can be calibrated or referenced to each other and to the Z-axis controller coordinates of the MVIS 501. The optical pen electronics 160′ and the vision system controller 502 can be configured to exchange data and control signals according to known methods to support coordinated adjustment (e.g., mechanical movement) of the optical pen 120′ and the optical imaging system 534.

[0062] Figure 5 Blocks illustrating exemplary control circuitry and / or routines are shown. Each block includes a computer and user interface 506, a vision system controller 502 which acts as a host system for communicating with the optical pen electronics section 160' and includes a probe head controller 503, a position latch 504, and a motion controller 505. All blocks are interconnected to each other and to various components of the machine vision and inspection system 501 via a power and control bus 510. Figure 5 In this embodiment, the power and control bus is connected to the probe system 536 via connection 592. The optical pen electronics section 160' can perform measurements using the optical pen 120' and exchange control and data signals with the computer and user interface 506 and / or the vision system controller 502.

[0063] The motion controller 505 of the MVIS 501 can be used to control a motion mechanism (e.g., motion mechanism 536b) to adjust the distance between the optical pen 120' and the surface to be measured (e.g., a workpiece or calibration object, etc.) to correspond to a distance where the surface to be measured is within the measurement range R of the optical pen 120'. As noted above, in various embodiments, the surface to be measured can also be positioned relative to the optical pen 120' in the X and Y axis directions (e.g., by movement of the probe system 536 and / or the workpiece stage 572, which can be moved along the X and / or Y axes on guide bearings 572a by movement of the motion mechanism 572b, which can be controlled by the motion controller 505). Specifically, as will be described in more detail below, in various embodiments, distance calibration data can be obtained (e.g., when performing a helical scan of the upper surface of a spherical calibration object 700), for which relative movement in the X and Y axis directions can be made (e.g., using motion mechanism 572b, etc.). In some implementations, as part of such a process, the Z position of the optical pen 120′ (e.g., in the machine coordinate system) can be kept constant (e.g., where the motion mechanism 536b of the Z motion mechanism can also be represented as not being used to move the optical pen 120′ when performing a helical scan to obtain distance calibration data).

[0064] In various embodiments, the measuring machine (e.g., MVIS) may include alternative configurations for achieving relative movement along the X-axis and / or Y-axis directions. For example, instead of stage 572 being movable in both the X-axis and Y-axis directions, stage 572 may be movable in only one direction (e.g., the X-axis direction, moved by motion mechanism 572b), while probe system 536 may be movable in the other direction (e.g., the Y-axis direction, moved by a corresponding motion mechanism). In other embodiments, stage 572 may be fixed, while probe system 536 may be movable in both the X-axis and Y-axis directions (e.g., moved by corresponding motion mechanisms). In various embodiments, including Figure 5 The measurement system 500 of the measuring machine (MVIS) 501 may include a high-precision motion mechanism, which enables the relative X-axis and Y-axis movement of the optical pen 120′ relative to the spherical calibration object 700 to have an accuracy better than 1 micrometer, and enables the X and Y coordinates indicating the position of each measured surface point in the distance indication data obtained from the helical scan to have high accuracy.

[0065] In various implementations, position latch 504 provides a latching signal. In one embodiment, position latch 504 of vision system controller 502 helps ensure that the XYZ coordinates (e.g., MCS coordinates) of probe system 536 with optical pen 120′ (e.g., controlled by motion controller 505) are properly synchronized with measurements from optical pen 120′. For example, position latch 504 can generate a latching signal corresponding to a time point when a CRS measurement is performed, for which the latching signal also causes the XYZ coordinates of probe system 536 in the machine coordinate system to be determined / recorded / latched from the same time point. Thus, the CRS measurement of optical pen 120′ (e.g., indicating Z distance) can be combined with the XYZ coordinates of probe system 536 (i.e., indicating the XYZ position of probe system 536 and optical pen 120′ when the measurement is performed) to determine total position data / measurements within the machine coordinate system. As described in more detail below, as part of certain calibration operations, the Z position of the probe system 536 may be kept constant, wherein the position latch may be primarily about the XY coordinates of the probe system 536 and the corresponding optical pen 120′, the XY coordinates being combined with the CRS measurement (e.g., indicating the Z distance) of the optical pen 120′ to the corresponding surface point on the spherical calibration object 700 (i.e., at the corresponding XY coordinates).

[0066] Generally, the various blocks outlined above can be configured using components and operations similar to or identical to those used in some previously known systems. It should be understood that in various embodiments, the operation of the blocks outlined above can be performed using a general-purpose processor, etc., and in various embodiments, the circuitry and / or routines associated with the various blocks may be combined or indistinguishable. The operation of scanning the spherical calibration object 700 with an optical pen 120' to obtain distance calibration data (e.g., distance calibration data 400A, 400B, or 1100) of the CRS system 100' will be described in more detail below.

[0067] Figure 6 This is a block diagram of a second exemplary embodiment of a measurement system 600, which includes a measuring machine 601 (e.g., a coordinate measuring machine (CMM)) integrated with a CRS system 100″ for measuring a workpiece. Figure 6 In the example, certain portions of the CRS system 100″ are included as parts of the interchangeable CRS optical probe system 615. That is, the CRS optical probe system 615 is automatically interchangeable with other types of CMM probes. The CRS optical probe system may also be referred to herein simply as a CRS optical probe. Figure 6 Includes orthogonal XYZ coordinate axes of the Machine Coordinate System (MCS) used as a reference frame for CMM 601. Figure 6In the configuration shown, the Z-axis of the MCS is parallel to the Z-direction of the optical pen 120″, which is defined as being parallel to the optical axis of the optical pen 120″, which is the distance measurement axis of the optical pen 120″.

[0068] The measurement system 600 includes a coordinate measuring machine controller 602, a computer and user interface 606, probe signal processing and control circuitry 607, and a coordinate measuring machine 601. The controller 602 includes a probe head controller 603, a position latch 604, and a motion controller 605. The CRS optical probe 615 includes an automatic connector element 636 and is connected to the coordinate measuring machine 601 via mating connector elements in an automatic connector connector 630 (also referred to as an automatic connector connector).

[0069] In various embodiments, the coordinate measuring machine 601 communicates with all other components via a data transmission line 610 (e.g., a bus), which is connected to a probe head cable 611 via a connector 608 (e.g., a "miniature D" connector). This probe head cable supplies signals to and from the CRS optical probe 615. The coordinate measuring machine 601 is controlled by a coordinate measuring machine controller 602, while the CRS optical probe 615 is connected to a probe signal processing and control circuit 607 (e.g., in one embodiment, including a measurement signal processing and control element 160B, as referenced above). Figure 1 The components (as outlined in component 160B) exchange data and are controlled by the probe signal processing and control circuitry. In various embodiments, the user can control some or all of the components via a computer and user interface 606.

[0070] The CRS optical probe 615 includes: probe electronics 675, which includes a light source and wavelength detector portion 160A″ (e.g., in one embodiment, it includes a light source and a wavelength detector, as referenced above). Figure 1 (as outlined in component 160A); and an optical pen 120″ which guides the measurement beam 196″ toward the measurement surface. In various embodiments, data associated with the optical pen 120″ (e.g., identification data, distance calibration data, compensation data, etc.) may be stored externally to the CRS optical probe 615 (e.g., in the probe signal processing and control circuitry 607). In alternative embodiments, portions of such data may be stored or otherwise encoded within portions of the CRS optical probe 615.

[0071] The CRS optical probe 615 includes an optical pen 120″ of the CRS system 100″ for use in conjunction with various measurement functions. In this configuration, standard coordinate measuring machine technology can be used in conjunction with a motion controller 605 to automatically position the CRS optical probe 615 with the optical pen 120″ having a measurement beam 196″ about the workpiece, enabling the execution of measurement functions (e.g., those described in the incorporated references). As will be described in more detail below, certain similar operations can be performed as part of a calibration method for obtaining distance calibration data for the CRS system 100″ including the optical pen 120″, including measuring a spherical calibration object 700 (e.g., see...). Figure 7 ).

[0072] In various implementations, position latch 604 provides a latching signal. In one embodiment, position latch 604 of coordinate measuring machine controller 602 helps ensure that the XYZ coordinates of coordinate measuring machine 601 (e.g., controlled by motion controller 605) are properly synchronized with measurements from optical pen 120″. For example, position latch 604 can generate a latching signal corresponding to a point in time when a CRS measurement is performed, for which the latching signal also enables the coordinates of CMM 601 (e.g., in machine coordinate system) to be determined / recorded / latched from the same point in time. Thus, CRS optical probe measurements (e.g., indicating Z distance) can be combined with the XYZ coordinates of the CMM (i.e., indicating the position of CRS optical probe 615 and optical pen 120″ in the MCS when the measurement is performed) to determine total position data / measurements within the MCS.

[0073] Generally, the various blocks outlined above can be configured using components and operations similar to or identical to those used in some previously known systems. It should be understood that in various embodiments, the operation of the blocks outlined above can be performed using a general-purpose processor, etc., and in various embodiments, the circuitry and / or routines associated with the various blocks may be combined or indistinguishable. The operation of scanning the spherical calibration object 700 with an optical pen 120″ to obtain distance calibration data (e.g., distance calibration data 400A, 400B, or 1100) of the CRS system 100″ will be described in more detail below.

[0074] Figure 7 A CRS system 100 with an optical pen 120 is shown (e.g., attached to, for example...). Figure 5 and 6An embodiment of a spherical calibration object 700 for distance calibration data of the measuring machine (CRS) shown is presented. The spherical calibration object 700 includes a nominal spherical calibration surface 704 having a vertex TP (e.g., the highest point along the Z-axis) and is typically supported by a support structure 706 on a surface plate 708 (e.g., which may be part of or positioned on the surface plate 708). The spherical calibration object 700 has a nominal radius Rs and a reference center Cs. As will be described in more detail below, measurements performed on the spherical calibration object 700 can be used to determine the distance calibration data of the CRS system 100.

[0075] Figure 8 A spiral scan 800 is shown performed on the top of the nominal spherical calibration surface 704 of the spherical calibration object 700. Figure 8 The illustration is a two-dimensional top view showing a spiral scan performed in three dimensions above the top of the spherical calibration object 700. The X and Y axis positions are relative to the measuring machine used to move the optical pen 120 (e.g., Figure 5 The machine vision inspection system 501, or Figure 6 The coordinate system is consistent with that of the coordinate measuring machine (such as the 601). Figure 8 The spiral scanning pattern illustrates the movement of the optical pen 120 and the measurement beam 196 on the top surface of the spherical calibration object 700 (e.g., in the X and Y axis directions) (e.g., when the optical pen 120 is maintained at a constant Z height along the Z axis).

[0076] In various implementations, as part of a spiral scan, several surface points can be measured to determine distance indication data corresponding to the distance between each corresponding surface point on the nominal spherical calibration surface of the colorimetric range sensor optical pen 120 and the spherical calibration object 700. Figure 8 The examples show several example surface points (e.g., surface points P0, PE1 to PE8, PS1 to PS9, PW1 to PW9, PN1 to PN8), but it should be understood that in various embodiments, additional surface points can be obtained along the spiral scan pattern (e.g., in addition to and / or alternatives). Figure 8(Example surface points shown). For example, in some embodiments, the number of surface points measured can be hundreds or thousands. As an example, if an average Z-axis step size of about 10 micrometers is required, and if the measurement range R of the optical pen 120 is about 100 micrometers, this corresponds to measuring about 10 surface points (i.e., equal to 100 / 10) within the 100-micrometer range to determine the desired distance calibration data. As another example, if an average Z-axis step size of about 1.0 micrometer is required, and if the measurement range R of the optical pen 120 is about 100 micrometers, this corresponds to measuring about 100 surface points (i.e., equal to 100 / 1) within the 100-micrometer range to determine the desired distance calibration data (e.g., this corresponds to higher accuracy than the 10-micrometer step size example). As another example, if an average Z-axis step size of about 0.3 micrometers is required, where the measurement range R of the optical pen 120 is about 300 micrometers, this corresponds to measuring about 1,000 surface points in the 300-micrometer range (i.e., equal to 300 / 0.3) to determine the desired distance calibration data.

[0077] In various implementations, as the helical scan proceeds further away from the center, it may be necessary to increase the frequency of surface points measured as part of the helical scan. Specifically, it should be noted that the further the helical scan is from the center, the faster the change in Z-distance between surface points may occur (i.e., the slope of the spherical calibration object 700 increases with distance from the vertex TP). Accordingly, if approximately equal Z-height steps are desired between subsequently measured surface points, the further the helical scan proceeds from the center point P0, the more frequently surface points may need to be measured along the helical scan (e.g., at intervals between measured surface points, which would make the Z-height steps approximately equal between each surface point).

[0078] exist Figure 8 In the example, each example surface point has corresponding X and Y axis coordinates. At the center of the spiral scan pattern is the center point P0 with coordinates X0, Y0. Extending to the right are example surface points PW1 to PW9, where surface point PW1 is at coordinates XW1, Y0, surface point PW2 is at coordinates XW2, Y0, etc. Extending to the left are surface points PE1 to PE8, where surface point PE1 is at coordinates XE1, Y0, surface point PE2 is at coordinates XE2, Y0, etc. Extending downwards are surface points PS1 to PS9, where surface point PS1 is at coordinates X0, YS1, surface point PS2 is at coordinates X0, YS2, etc. Extending upwards are surface points PN1 to PN8, where surface point PN1 is at coordinates X0, YN1, surface point PN2 is at coordinates X0, YN2, etc. For Figure 8For the sake of simplicity, the specific set of example surface points shown are labeled with the same Y-axis coordinate Y0 for example surface points PW1 to PW9 and PE1 to PE8 (e.g., where a line extending through the example surface points in the two-dimensional representation is parallel to the X-axis). Surface points PN1 to PN8 and PS1 to PS9 are labeled with the same X-axis coordinate X0 (e.g., where a line extending through the example surface points in the two-dimensional representation is parallel to the Y-axis). It should be understood that in the three-dimensional representation and / or different side views (e.g., as shown in the side view), the surface points may differ slightly from the surface points in the two-dimensional representation. Figure 9A and 9B As shown in the figure, the line passing through the example surface point can be curved (e.g., depending on the shape of the top of the spherical calibration object 700).

[0079] It should be understood that, for Figure 8 For a given example surface point, as the helical scan travels around the helical pattern, the example surface point appears at different angular orientations (e.g., for...). Figure 8 Example surface points (with approximately 90-degree intervals). For example, starting from surface point PE1, rotating approximately 90 degrees each time along the spiral pattern, is surface point PS1, followed by surface points PW1, PN1, PE2, PS2, and so on. It should be understood that, depending on the geometry of the spiral pattern, the X and Y coordinates of each corresponding surface point along the spiral pattern can be at a correspondingly greater radial distance from the center point P0. For example, the radial distance of PW1 (e.g., corresponding to XW1-X0) can be greater than the radial distance of PS1 (e.g., corresponding to Y0-YS1), and the radial distance of PS1 can be greater than the radial distance of PE1 (e.g., corresponding to X0-XE1). It should be understood that such calculations of radial distances can generally be based on the absolute value of the distance between the corresponding coordinates of the corresponding points. As will be described in more detail below, in, for example, where vertex TP is located at the same position as the center point P0′... Figure 9A In the example, the radial distance from the surface point to the vertex TP is the same as the radial distance to the center point P0′. In contrast, in, for example... Figure 9B In the example, when the center point P0″ is not in the same position as the vertex TP, the radial distance to the vertex TP will be different from the radial distance to the center point P0″.

[0080] about Figure 8 As an example, it can be noted that the outer portion of the helical scan includes a partial helical scan portion, such as the portion containing surface points PS9 and PW9. It should be understood that such partial helical scan portions may arise because the vertex TP of the spherical calibration object is not perfectly aligned with the center point P0 of the helical scan. More specifically, Figure 8The scanned surface points correspond to points within the measurement range R of the optical pen 120. Therefore, when the outer portion of the spiral scan reaches points on the spherical calibration object outside the range R of the optical pen 120, no surface point is shown as being measured in the spiral scan (i.e., because such surface points are outside the range R). Thus, the discontinuous portion of the spiral scan containing points PS9 and PW9 can indicate that the vertex TP of the spherical calibration object may be located at a different position than the center point P0 of the spiral scan (e.g., approximately between surface points PW1 and PS1, or otherwise deviated from the center point P0, for example, in the southwest direction in the example shown).

[0081] As will be described in more detail below, in, for example Figure 9A In the example, as a part of the helical scan measurement at each surface point, each further radial distance roughly corresponds to a measurement distance further away from the optical pen 120 along the Z-axis. As noted above, although for the sake of illustration only... Figure 8 The diagram shows a relatively small number of surface points, but in various embodiments, a larger number of surface points (e.g., hundreds or thousands) can be measured as part of the helical scan to determine distance calibration data. As will be described in more detail below, Figure 9A An example is shown where the center point P0′ of the helical scan is located at the same position as the vertex TP of the spherical calibration object 700, while Figure 9B An example is shown in which the center point P0″ of the spiral scan is offset from the vertex TP of the spherical calibration object 700.

[0082] Figure 9A This shows a spiral scan of the top of the nominal spherical calibration surface 704, which serves as the spherical calibration object 700 (e.g., Figure 8 A cross-sectional side view of some example surface points P0′ to PW9′ measured in a partial spiral scan. Figure 9A In the example, only surface points P0′ to PW9′ are shown for simplicity, but it should be understood that additional surface points (e.g., surface points PE1′ to PE8′) can be similarly shown on the left side of such examples. Figure 9A In the diagram, the optical pen 120 is shown maintaining a constant Z-position / height in the machine coordinate system during the helical scanning process, wherein the constant Z-position / height can be represented as the Z-height ZCAL. The distances Z0′ to ZW9′ between the optical pen 120 and the corresponding surface points P0′ to PW9′ are respectively shown as being between the surface points P0′ to PW9′ and the calibrated Z-height ZCAL. As described above, when measuring each corresponding surface point (i.e., where the distance between the optical pen 120 and the corresponding surface point is measured), the optical pen 120 has a measurement beam 196 directed at each corresponding surface point.

[0083] like Figure 9AAs shown, the measurement range R of the optical pen covers the minimum measurement distance ZMIN to the maximum measurement distance ZMAX. To initiate a helical scan, the optical pen 120 is positioned relative to the spherical calibration object 700 such that the minimum measurement distance ZMIN is close to / near the vertex TP of the nominal spherical calibration surface 704. In various embodiments, the minimum measurement distance ZMIN may be slightly above or below the vertex TP. In one embodiment, the minimum measurement distance ZMIN may be just above the vertex TP to help ensure that the desired surface points, such as surface points P0′ to PW9′ used to determine the desired distance calibration data, will all be within the measurement range R of the optical pen 120. In another embodiment, the minimum measurement distance ZMIN may be just below the vertex TP to help ensure that the entire measurement range R of the optical pen 120 corresponds to a surface point on the nominal spherical calibration surface 704 of the spherical calibration object 700. In such implementations, the vertex TP may not be within the measurement range R of the optical pen 120 (e.g., just above the measurement range R), but the position of the vertex TP can still be determined or otherwise indicated (e.g., based on distance indication data from the helical scan and known characteristics of the nominal spherical calibration surface 704), as will be described in more detail below.

[0084] Figure 9A The specific examples described herein are applicable to depicting certain relationships that may occur when the center point P0′ of the helical scan corresponds exactly to the vertex TP of the spherical calibration object 700. It should be understood that while the approximate / coarse location of the vertex TP may be known (e.g., such localization is achievable), in some cases the precise location of the vertex TP may often be unknown (e.g., regarding the exact X, Y coordinates). Such precise locations can be determined by other processes (e.g., based on distance indication data from the helical scan), as will be discussed below relative to... Figure 9B The examples are described in more detail.

[0085] According to, for example Figure 8 Due to the general characteristics of helical scanning, each corresponding point in the helical pattern will be further away from the center point P0′. Correspondingly, in Figure 9A In the example, since the center point P0′ corresponds to the vertex TP (i.e., has the same X, Y coordinates as the vertex TP), each of the corresponding surface points along the spiral scan will have a radial distance in X, Y coordinates from the vertex. Correspondingly, based on the geometry of the nominal spherical calibration surface 704, each of the subsequent distances ZW1′ to ZW9′ will be greater than the previously corresponding Z distance. Therefore, the corresponding wavelength peak 302 corresponding to the measurements of the subsequent measurement points P0′ to PW9′ (e.g., see...) Figure 3 Each of them in ) will be on the wavelength measurement axis (e.g., Figure 3 (As shown in the diagram) Shift to the right, where the corresponding distance indicator coordinates for each peak will have higher values.

[0086] exist Figure 10 Such a relationship is illustrated in curve 1010′, where each point P0′ to PW9′ is shown as having corresponding distance indicator coordinates that increase and correspond to an increasing radial position (i.e., where, according to the geometry of the nominal spherical calibration surface 704, the increasing radial position corresponds to an increasing Z distance). Figure 10 In the middle, curve 1010′ contains Figure 9A The data for surface points P0′ to PW9′, while curve 1010″ contains Figure 9B The data for surface points P0″ to PW9″ will be described in more detail below. Figure 10 In the example, curve 1010″ overlaps curve 1010′, where the two curves are extremely similar or identical. Figure 10 In curve 1010′, the radial position indicates the distance of the X, Y coordinates of the corresponding surface point from the X, Y coordinates of the vertex TP. Therefore, it should be understood that in various embodiments, the X, Y position of the vertex TP (e.g., determined or otherwise known) is related to the radial position of each surface point (e.g., and can be used to determine said radial position). As will be discussed regarding... Figure 9B In a more detailed description, in examples where the center point P0″ is offset from the vertex TP, a fitting process and / or other calculations can be used to determine and / or appropriately fit the measured values ​​of the surface points to the curve 1010″, for example... Figure 10 The curve.

[0087] about Figure 9A and 10 Examples should be understood regarding Figure 8 Example points along the spiral scan, the corresponding additional points will fall on Figure 10 Between the points shown. More specifically, along curve 1010′, between surface points P0′ and PW1′, there will be surface points PE1′ and PS1′ respectively. Similarly, between surface points PW1′ and PW2′, there will be surface points PN1′, PE2′, and PS2′ respectively, and so on, where all subsequent surface points will continue along... Figure 10 The curves 1010′ shown are arranged as follows. As noted above, in various embodiments, in addition to or instead of Figure 8 The example surface points shown can be used to measure many other surface points. At this point, there is a perfect alignment between the center point P0′ and the vertex TP. Figure 9A In the example, each subsequent surface point measured along the spiral scan will be along Figure 10The curve 1010′ is positioned further away, corresponding to a radial position farther from the vertex TP and subsequently higher / greater distance indicating coordinates. Similarly, this property is a result of the geometry of the nominal spherical calibration surface 704 of the calibration object 700, where each subsequent surface point further along the spiral scan and therefore farther from the vertex TP will have a corresponding Z distance greater than that of the optical pen 120, which is maintained at a constant Z height ZCAL during the spiral scan.

[0088] like Figure 9A As shown, the radial position of each measured surface point with respect to vertex TP can be used to determine the exact Z-height / position of each measured surface point (i.e., based on the known curve / geometric properties of the nominal spherical calibration surface 704). As will be described in more detail below, for Figure 9B The radial position of the measured surface point (i.e., relative to the vertex TP) is still unknown due to the helical scan, because the exact position of the vertex TP is unknown (i.e., not exactly relative to the vertex TP). Figure 9B The center point P0″ of the spiral scan is consistent. However, due to the known properties / characteristics of the spiral scan (e.g., where the X, Y positions of each measured surface point are known) and the nominal spherical calibration surface 704, the distance indication data acquired during the spiral scan (e.g., containing the known X, Y positions of each measured surface point and the corresponding distance indication coordinates determined from the measurement of each surface point) can be used to determine / infer the X, Y position of the vertex TP and / or the corresponding radial position of each measured surface point (e.g., relative to the vertex TP).

[0089] In one implementation, the X, Y position of vertex TP and / or the corresponding radial position of each measured surface point can be determined by performing a process that involves minimizing the fitting error of the curve in the XY direction (i.e., the curve indicating the distance data), such as by performing iterations by trying different positions of vertex TP until the fitting error is minimized. In other implementations, the X, Y position of vertex TP and / or the corresponding radial position of each measured surface point can be determined alternatively or additionally using various other types of calculations. As some specific simplified example values ​​regarding such calculations and / or curve fitting techniques, it should be noted that... Figure 9BThe measurements of surface points P0″ and PW1″ will produce the same distance indication coordinates. In such cases, it can be inferred that vertex TP is equidistant from surface points P0″ and PW1″ (i.e., based on the known properties / characteristics of the nominal spherical calibration surface 704). Furthermore, if the X, Y coordinates of vertex TP lie on the line between the X, Y coordinates of surface points P0″ and PW1″, then the radial position / distance to another surface point (e.g., surface point PW2″) should correspond / consistent with certain values ​​(i.e., if vertex TP is located at an assumed position between surface points P0″ and PW1″, then the measured distance indication coordinates of surface point PW2″ should correspond to a Z height / position consistent with the radial distance to vertex TP).

[0090] In contrast, if vertex TP is not on the line between surface points P0″ and PW1″, but is still equidistant from these two surface points, different positions of vertex TP can be determined (e.g., using iterations at different experimental positions equidistant from surface points P0″ and PW1″) to determine the position of vertex TP consistent with the distance-indicating coordinates determined for other surface points (e.g., surface point PW2″, etc.). Although provided with... Figure 9B Such example values ​​are provided for simplification, but it should be understood that, given the known properties / characteristics of the helical scan and the nominal spherical calibration surface 704, other known types of similar calculations and / or curve fitting (e.g., minimizing the curve fitting error) techniques can be used to determine the position of the vertex TP and / or the radial position of the measured surface points based on the distance indication data acquired during the helical scan.

[0091] exist Figure 9B In the example, as noted above, the center point P0″ of the helical scan is offset from the vertex TP of the nominal spherical calibration surface 704 of the spherical calibration object 700, and the surface points P0″ to PW9″ of the helical scan are shown therein. Apart from this difference, Figure 9B Some characteristics will be understood as similar to Figure 9A The characteristics, and therein shown Figure 9A Surface points P0′ to PW9′ to in Figure 9B The comparison is shown in the graph. Figure 9B In the example, as noted above, surface points P0″ and PW1″ are approximately equidistant from vertex TP, and in this example, vertex TP can be considered to lie exactly between surface points P0″ and PW1″ (e.g., equidistant from the surface points). At this point, it should be understood that the Z distances Z0″ and ZW1″ are approximately equal (i.e., since points P0″ and PW1″ are at equal distances on opposite sides of vertex TP). Therefore, in Figure 10In curve 1010″, points P0″ and PW1″ are indicated to correspond to the same distance indication coordinates when measured by optical pen 120, and correspondingly, their X and Y coordinates relative to the vertex TP are at the same radial position / distance (i.e., in the X and Y coordinates of the machine coordinate system).

[0092] about Figure 9B For example, it should be understood that, according to curve fitting or other techniques such as those mentioned above, along, for example... Figure 10 Correct plotting of the surface points measured by curve 1010″ may require a proper fit to such a curve (e.g., correctly determining the radial position / distance of each surface point). For example, again regarding the example mentioned above, if one attempts to plot point P0″ at the same location as point P0′ (i.e., based on the incorrect assumption that point P0″ is at the location of vertex TP) and plot surface point PW1″ at the same location as surface point PW1′, an incorrect curve will be produced (i.e., with an error relative to the expected value) (e.g., possibly observed / determined based on unfitted / inconsistent with known properties of the nominal spherical calibration surface 704). Specifically, plotting points P0″ and PW1″ at different locations along the curve will not conform to the known property that different distances indicate coordinates should correspond to different radial positions (e.g., where differences regarding such known properties can be considered as errors that should be minimized as part of the curve fitting process, etc.). More specifically, measurements of surface points P0″ and PW1″ will produce the same distance indicator coordinates (i.e., due to equal distances Z0″ and ZW1″), which should correspond to the same radial position of each surface point P0″ and PW1″ relative to vertex TP. By performing a process that correctly determines the radial position of each surface point P0″ to PW9″ relative to vertex TP (e.g., to correspond to known properties, etc.), a correctly fitted curve (i.e., where the fitting error is minimized) can be obtained, such as... Figure 10 Example curve 1010″ is shown.

[0093] In some implementations, such curve fitting or similar calculations and / or techniques can effectively correspond to performing iterations, where the X, Y coordinates of vertex TP are tried at different locations, and where different corresponding radial positions / distances of surface points are determined / plotted. Such iterations can continue until the resulting curve and / or the corresponding radial position / distance fits the expected value / has the minimum fitting error of the curve (e.g., the X, Y coordinates of vertex TP are also effectively determined). Distance calibration data corresponding to each surface point P0″ to PW9″ can also be correctly determined by correctly determining the radial position of each surface point P0″ to PW9″ relative to vertex TP. It should be noted that the plotted curve 1010″ is substantially the same as the plotted curve 1010′, therefore, it is shown... Figure 9BThe spiral scan—even if the center point P0″ is offset relative to the vertex TP—produces accurate distance calibration data (e.g., corresponding to curves 1010′ or 1010″ to...). Figure 11 The transformation of curve 1110 will be described in more detail below.

[0094] Figure 11 It correlates the distance indicator coordinates with the measured distance to the surface in a manner similar to... Figure 4A The distance calibration data curve of CRS distance calibration data 1110 is represented in Figure 1100. Figure 10 The curve 1010′ or 1010″ to Figure 11 The conversion of curve 1110 requires... Figure 10 Radial position conversion to Figure 11 The Z position / distance. In various implementations, such a transformation can be performed based on known geometric characteristics / principles, where a given radial distance from the vertex TP along the nominal spherical calibration surface 704 will produce a known corresponding Z position / distance for each surface point (e.g., based on known geometry and trigonometric relations and properties, etc.).

[0095] It should be noted that Figure 11 conveyed with Figure 4A The calibration curve 410A provides similar information and may be similar to that described above. Figure 4A And utilize. In various implementation schemes, when determined according to the principles disclosed herein, for example by... Figure 11 When distance calibration data is shown, such determined distance calibration data can be used for various purposes. For example, for optical pens where there was no previously determined distance calibration data, or for optical pens where existing distance calibration data is to be replaced. Figure 11 The distance calibration data shown can be stored in the calibration section 169 of the memory section 168 of the electronic component section 160. Alternatively, in, for example... Figure 11 In an implementation scheme where distance calibration data, such as distance calibration data, is used to perform accuracy checks on the stored distance calibration data of an optical pen, it is possible to... Figure 11 The distance calibration data is compared with previously stored distance calibration data to determine if there are significant differences. In various implementations, if a significant difference is found, the user may be alerted that the stored distance calibration data may be inaccurate, which may require further action (e.g., further testing / verification and / or sending the optical pen 120 back to the factory or other facility for a full factory calibration, etc.).

[0096] Regarding the general properties of the spherical calibration object 700, it is anticipated that the spherical calibration object has a high-precision nominal spherical calibration surface 704. It should be noted that the spherical calibration object 700 may have a nominal spherical calibration surface 704, but may not be a complete sphere (e.g., it may be a hemisphere or a smaller portion of a sphere that provides a nominal spherical calibration surface 704 usable according to the principles disclosed herein, for example...). Figure 9A and 9B (As shown in the diagram). Due to the high-precision nature of the surface 704 of the spherical calibration object 700, each increasing radial distance originating from the vertex TP will correspond to a longer distance Z between the optical pen 120 and the corresponding surface point on the spherical calibration object. At this point, determining the exact position of the vertex TP allows the distance indication data obtained from the helical scan to be accurately correlated with the correct Z distance / position, as shown in the diagram. Figure 11 As shown in the image.

[0097] As a relative Figure 9B A quick example, such as Figure 10 As shown, if points P0″ and PW1″ were instead plotted at the radial positions of points P0′ and PW1′ respectively (e.g., due to...) Figure 9B If the vertex TP is located at the surface point P0″ (an inaccurate assumption), then the radial positions indicated by points P0″ and PW1″ will be inaccurate. Therefore, the radial position is used to correspond to... Figure 11 The Z position / distance in the graph of the calibration data. Conversely, regarding... Figure 9B For example, by correctly determining the position of vertex TP, as Figure 10 As shown (determined based on a correct fit between the curve obtained from the distance indication data from the helical scan and the expected curve characteristics (e.g., minimizing the fitting error of the curve in the XY direction)), surface points P0″ and PW1″ can be correctly associated with the same radial position, where Figure 11 The corresponding distance indicator coordinates can be correctly associated with the correct Z position / distance (e.g., according to...). Figure 10 (The radial position is determined). As previously stated, given the high-precision surface 704 of the spherical calibration object 700, according to the trigonometric principle, each radial position corresponds to an exact Z position / distance, because each measured surface point is determined to be at a certain corresponding distance from the vertex TP.

[0098] Figure 12 This is a flowchart illustrating an exemplary embodiment of routine 1200, which is used to determine distance calibration data for a colorimetric range sensor system by measuring surface points of a spherical calibration object. Routine 1200 may be employed, for example, by one or more embodiments of the colorimetric range sensor system described herein. For convenience, refer to... Figures 8 to 11Description of routine 1200. The colorimetric range sensor system has a colorimetric range sensor optical pen 120 coupled to a measuring machine having a machine coordinate system. The colorimetric range sensor optical pen 120 is configured to focus different wavelengths at different distances along a distance measurement axis close to the surface of the workpiece to be measured.

[0099] Routine 1200 begins at 1202, wherein the colorimetric range sensor optical pen 120 is arranged in a certain relationship relative to a spherical calibration object 700 having a nominal spherical calibration surface 704. For example, the colorimetric range sensor optical pen 120 may be positioned such that the minimum CRS measurement distance ZMIN is close to the vertex TP of the nominal spherical calibration surface 704 of the spherical calibration object 700. Routine 1200 proceeds from 1202 to 1204.

[0100] At 1204, routine 1200 controls the measuring machine to achieve relative movement of the colorimetric range sensor optical pen 120 about the nominal spherical calibration surface 704 to obtain distance indication data. In some embodiments, when obtaining distance indication data, a constant Z height (e.g., maintaining the same Z coordinate) of the colorimetric range sensor optical pen 120 can be maintained in the machine coordinate system above the nominal spherical calibration surface 704.

[0101] Compared to other possible scanning modes used to obtain distance indication data, such as those mentioned above... Figures 8 to 9B The described spiral scan can have advantages. Particularly regarding the use of spherical calibration objects, it may be desirable to begin the scan at or near the vertex TP of the spherical calibration object (e.g., a spiral scan starting at the center position P0 is particularly suitable for starting at or near the vertex TP) to help ensure that the spiral scan will cover the effective portion of the optical pen's range R, for example... Figure 9A and 9B As shown in the diagram. More specifically, in an example where the optical pen 120 is not yet calibrated and there is no distance indication calibration data, it may be uncertain where the minimum distance ZMIN and the maximum distance ZMAX will be relative to the optical pen 120. For example, if the scan pattern begins at a position away from the spherical calibration object, this may correspond to a distance beyond distance ZMAX, outside the effective range R of the optical pen, where a valid measurement point cannot be obtained in the initial portion of the scan. Instead, by performing a spiral scan with the center position P0 located at or near the vertex TP of the spherical calibration object, the probability that the spiral scan will cover at least a majority of the effective measurement range R of the optical pen 120 to measure surface points on the spherical calibration object is increased.

[0102] Therefore, the relative movement of the colorimeter range sensor optical pen 120 can be a spiral pattern referenced in the XY plane (e.g., an XY plane located at or parallel to the XY plane at the calibration Z height ZCAL) to perform a spiral scan of the top of the nominal spherical calibration surface 704, wherein distance indication data is determined to correspond to the distance between the colorimeter range sensor optical pen 120 and a surface point on the nominal spherical calibration surface 704 during the spiral scan. The distance indication data can be as described above regarding... Figures 8 to 9B As described, the Z-distance is obtained by indicating the location corresponding to the peak. As discussed above, the number of surface points for which the distance indication data is determined can be hundreds or thousands, and may include, for example, at least 100 surface points. Routine 1200 proceeds from 1204 to 1206.

[0103] In 1206, routine 1200 determines distance calibration data for the chromaticity range sensor system based on the obtained distance indication data. As part of this process, the relative position of each surface point with respect to the vertex of the nominal spherical calibration surface is determined.

[0104] In some embodiments, distance indication data acquired during helical scanning can be evaluated to determine the location of the vertices of the nominal spherical calibration surface 704 and the relative positions of each surface point. For example, the vertices can be determined by minimizing the fitting error of the curves in the XY directions (e.g., from the distance indication data of the helical scanning), as described above regarding... Figure 9B and 10 To describe in more detail. For example, a fitting routine can be performed to minimize the fitting error of the curve in the XY direction, which can be used to determine the vertex position of the spherical calibration object 700, for example, based on the best fit of the expected curve when distance indication data obtained from the helical scan is obtained (e.g., particularly as described above regarding...). Figure 10 (As described above) converges. Such fitting routines can be performed iteratively, where different hypothetical vertex positions are tried relative to the distance indication data obtained from the helical scan until the best-fit curve is obtained. It should be understood that other techniques can also be used, or alternatively, for such determination. For example, in some embodiments, certain calculations can be performed to determine vertex positions more quickly (e.g., calculations based on the principle that if two surface points, such as P0″ and PW1″, correspond to...). Figure 9B If the same distance indicates the coordinates in the example, then this indicates that the two surface points are located at radial positions equidistant from the vertex TP. The position of the vertex TP can be determined using trigonometric principles or other analyses.

[0105] In some embodiments, the known or stored location of the vertex TP of the nominal spherical calibration surface 704 can be used to replace or supplement the determined location of the vertex of the nominal spherical calibration surface 704. For example, the spherical calibration object 700 can be fixed on the stage of a measuring machine, wherein the vertex TP of the spherical calibration object can have a previously known XY position without evaluating data from a helical scan. In various embodiments, Figure 7 The spherical calibration object 700 can be placed by the user (e.g., on the stage of the measuring machine) for use in accordance with the principles disclosed herein (e.g., for performing a helical scan to determine distance calibration data).

[0106] In various implementations, surface points on the nominal spherical calibration surface are each located at the same nominal radius from a common internal center point of the spherical calibration object. The vertices of the nominal spherical calibration surface may be directly above the common center point and correspondingly have the same X and Y axis coordinates in the machine coordinate system as the common center point. The known or determined positions of the nominal radius and vertices at the common center point can be used to determine the distance calibration data. The relative position of each surface point with respect to the vertex corresponds to the radial position of each surface point, where, based on the known geometry of the nominal spherical calibration surface, each radial position corresponds to a known difference between the Z-axis coordinates of the vertex and the surface point in the machine coordinate system. This known information can be used with the obtained distance indication data to generate / determine the distance calibration data.

[0107] For example, in various embodiments, the known difference between the Z-axis coordinates corresponds to at least a portion of the measured distance from the optical pen to the surface point. For each surface point, the distance indication data includes distance indication coordinates, which are determined for the surface point based on the wavelength measurement peak generated from the measurement of the detector array 163 along the wavelength measurement axis of the wavelength detector 162. The determination of the distance calibration data may involve relating the distance indication coordinates of each surface point to a distance corresponding to the measured distance from the optical pen to the surface point. The distance calibration data may be in the form of a calibration curve, for example... Figure 11 The curve shown.

[0108] An embodiment of a routine for determining distance calibration data for a colorimetric range sensor system by measuring surface points of a spherical calibration object is executable. Figure 12 Additional actions not shown in the text can be performed compared to Figure 12 Showing fewer actions, which can be combined or separated. Figure 12 The actions shown, and the actions that can be performed in various orders.

[0109] For example, routine 1200 may include actions to store or upload distance calibration data. For instance, the distance calibration data may be uploaded to, for example, […]. Figure 1The calibration section 169 of the electronic component 160 of the CRS system shown. Stored or uploaded distance calibration data can be used during subsequent measurements of the surface point. The distance indication coordinates of the surface point can be determined based on the wavelength peak generated from the measurement of the surface point along the wavelength measurement axis of the detector array, wherein the stored distance calibration data is used to determine the measurement distance (e.g., from the optical pen to the measured surface point) based on the measurement distance associated with the distance indication coordinates determined by the stored distance calibration data.

[0110] In some embodiments, in addition to distance indication data, intensity peak data may also be used. For each measurement distance within the working range of the optical pen (e.g., regarding...), Figures 3 to 4B As described, as part of its normal operation, the optical pen 120 may actually receive different total amounts of light. More specifically, refer to... Figure 3 The peak wavelength 302 is at a level of 0.93, attributed to the amount of light received at the surface point measured at this distance. In contrast, as the optical pen moves closer to or further from the surface, the peak wavelength 302 increases along... Figure 3 As the wavelength measurement axis shown is shifted left or right, the signal level (illumination amount) at different peaks may be higher or lower, depending on the actual amount of light received. This difference is part of the normal operation of the optical pen 120 and the light source, etc. (e.g., the light source may have different amounts of power provided for different light colors / wavelengths, etc., along this range). Such signal level differences may affect centroid calculations, etc., used to determine distance indication coordinates, and therefore may require compensation for these differences. In some embodiments, it may be desirable to have two calibration data curves for distance calibration data, such as... Figure 4A This is used to indicate the distance indicator coordinates and Z-height measurement, and to indicate how much illumination is generated at each measurement distance (e.g., Figure 3 The second curve (of the signal level in the curve).

[0111] For example, before or after performing a scan (e.g., a helical scan), in various embodiments, the relative position of the optical pen 120 may be moved upward and / or downward (e.g., along the Z-axis) relative to the spherical calibration object 700, such that only the distance Z from the optical pen 120 to the spherical calibration object 700 changes. For example, refer to Figure 9A and 9B The sweep can be performed within the range of Z-distance and intensity peak data generated during the sweep (e.g., where the measurement beam 196 points to position P0). An intensity versus peak pixel curve can be determined based on the intensity peak data. More specifically, refer to... Figure 3As the optical pen 120 moves to different distances from the spherical calibration object 700, for each distance Z, the peak pixel coordinates (PPC) will be located at different positions on the wavelength measurement axis, and the intensity (signal level) is recorded for each peak pixel coordinate position. This intensity peak data can be used for intensity normalization (e.g., as...). Figure 3 As shown, the signal level is indicated in normalized volts.

[0112] Alternatively, in some implementations, peak intensity data may be collected or roughly estimated during the process of collecting distance indication data. For example, data from a helical scan can be used to determine an approximation of the intensity normalization curve. More specifically, similar to the process described above where the optical pen is held at the same XY position and moved up and down along the Z direction to obtain different intensity normalization calibration data points, the height of the peak determined during the helical scan will typically each correspond to a different distance Z between the optical pen 120 and the corresponding surface point on the spherical calibration object 700, wherein the intensity (signal level) at each Z height and the corresponding peak pixel coordinates can be recorded as part of the intensity normalization curve.

[0113] After such intensity peak data is acquired (e.g., before, after, or during the helical scan process), intensity calibration can be applied to the peaks acquired from the helical scan before determining the distance indication coordinates. In some embodiments, intensity normalization calibration curves may not be collected. It should be noted that the collection of intensity normalization curves and their application for normalizing intensity (signal level) values ​​in the measured distribution signal may, in some embodiments, result in more accurate distance calibration data and / or subsequent corresponding measurements.

[0114] In various implementations, the disclosed calibration process can be performed periodically (e.g., to determine new or updated calibration data for the CRS system, or to verify the accuracy of current calibration data stored in the CRS system, etc.). In various implementations, the calibration data determined from the calibration process can be stored in the calibration section 169 of the CRS system 100 (e.g., as new calibration data, and / or replacing existing calibration data). If a difference is determined between the determined calibration data and existing calibration data, alerts / advice can be provided to the user (e.g., indicating that the currently stored calibration data may have a problem, for which new calibration data can be used, or that the CRS system 100 can be returned to the factory or other institution for factory calibration, or that other correction processes can be performed, etc.).

[0115] As described above, a method is provided for providing distance calibration data to a colorimetric range sensor system having a colorimetric range sensor optical pen coupled to a measuring machine. The colorimetric range sensor optical pen is configured to focus different wavelengths at different distances from the surface to be measured. The colorimetric range sensor optical pen is arranged in a certain relationship relative to a spherical calibration object having a nominal spherical calibration surface. The measuring machine is controlled to achieve relative movement of the colorimetric range sensor optical pen about the nominal spherical calibration surface. The relative movement of the colorimetric range sensor optical pen is helical to perform a helical scan on a portion of the nominal spherical calibration surface, wherein distance indication data is determined to correspond to the distance between the colorimetric range sensor optical pen and a surface point on the nominal spherical calibration surface during the helical scan. Distance calibration data for the colorimetric range sensor system is determined based on the distance indication data.

[0116] In some embodiments, determining the distance calibration data includes determining the relative position of each surface point with respect to the vertex of the nominal spherical calibration surface. Determining the distance calibration data may include using distance indication data acquired during helical scanning to determine the position of the vertex of the nominal spherical calibration surface and the relative position of each surface point. In some embodiments, each surface point on the nominal spherical calibration surface is located at the same nominal radius from the common internal center point of the spherical calibration object, and wherein the vertex of the nominal spherical calibration surface is directly above the common center point and correspondingly has the same X-axis and Y-axis coordinates in the machine coordinate system as the common center point (e.g., as shown regarding...). Figure 7 , 9A Examples and descriptions of 9B, etc.

[0117] In some implementations, the relative position of each surface point with respect to the vertex corresponds to the radial position of each surface point. Based on the known geometry of the nominal spherical calibration surface, each radial position may correspond to the known difference between the Z-axis coordinates of the vertex and the surface point in the machine coordinate system of the measuring machine.

[0118] In some implementations, the known difference between the Z-axis coordinates corresponds to at least a portion of the measured distance from the colorimetric range sensor optical pen to the surface point. For each surface point, the distance indication data includes distance indication coordinates determined for that surface point based on the wavelength peak value generated from the measurement along the wavelength measurement axis from the surface point. Determining the distance calibration data involves relating the distance indication coordinates of each surface point to the measured distance from the colorimetric range sensor optical pen to the surface point.

[0119] In some implementations, distance calibration data is stored. As part of subsequent measurements of the surface point, distance indication coordinates are determined for that surface point based on the wavelength peak value generated from the measurement along the wavelength measurement axis. The stored distance calibration data is used to determine the measurement distance from the colorimetric range sensor optical pen to the measured surface point based on the measurement distance associated with the distance indication coordinates determined by the stored distance calibration data.

[0120] In some implementations, the wavelength measurement axis is the axis of the detector array of the wavelength detector in the chromaticity range sensor system.

[0121] In some implementations, the colorimetric range sensor optical pen has a measurement range extending between a minimum measurement distance and a maximum measurement distance. Positioning the colorimetric range sensor optical pen relative to a spherical calibration object involves positioning the colorimetric range sensor optical pen such that the minimum measurement distance is close to the apex of the nominal spherical calibration surface of the spherical calibration object.

[0122] In some embodiments, to perform a helical scan, the surface points used to determine the distance indication data comprise at least 100 surface points. In some embodiments, the measuring machine is controlled during the helical scan to achieve relative movement of the colorimetric range sensor optical pen about a nominal spherical calibration surface, while maintaining a constant Z-height of the colorimetric range sensor optical pen in the measuring machine's machine coordinate system.

[0123] In some embodiments, the method includes determining intensity peak data as the amount of light received by the chromaticity range sensor optical pen at different distances between the chromaticity range sensor optical pen and the nominal spherical calibration surface. Intensity calibration data is determined based on the intensity peak data, wherein distance indication data may be determined at least in part based on the intensity calibration data.

[0124] In some implementations, determining the intensity peak data involves relative movement of the chromaticity range sensor optical pen to perform a sweep across a range of Z-axis distances from the nominal spherical calibration surface, while maintaining constant X-axis and Y-axis coordinates in the machine coordinate system of the measuring machine, and capturing intensity peak data during the sweep. Determining the intensity calibration data involves generating an intensity normalized calibration curve based on the captured intensity peak data.

[0125] In some implementations, determining peak intensity data involves capturing peak intensity data during helical scanning. Determining intensity calibration data involves generating an intensity normalized calibration curve based on the captured peak intensity data.

[0126] In some embodiments, a system is provided that includes a measuring machine, a colorimetric range sensor system, and a spherical calibration object. The measuring machine includes a motion controller. The system is configured to utilize the motion controller to achieve relative movement of the colorimetric range sensor optical pen about a nominal spherical calibration surface. A helical scan of the nominal spherical calibration surface is performed to determine distance indication data used to determine distance calibration data.

[0127] In some implementations, determining the distance calibration data includes determining the radial position of each surface point relative to the vertex of the nominal spherical calibration surface, where each radial position corresponds to the distance between the corresponding surface point and the colorimetric range sensor optical pen when measured according to the geometry of the nominal spherical calibration surface. Each distance is associated with distance indication coordinates determined for the corresponding surface point as part of determining the distance calibration data.

[0128] In some embodiments, the system is also configured to store distance calibration data and subsequently perform a measurement process to determine a measurement distance corresponding to the distance between the colorimetric range sensor optical pen and a surface point on the surface. The measurement process includes determining the distance indication coordinates of the surface point based on the wavelength peak value generated from measurements along the wavelength measurement axis from the surface point. The stored distance calibration data is used to correlate the distance indication coordinates with the corresponding measurement distance.

[0129] In some implementations, distance indication data corresponding to the distance between the colorimetric range sensor optical pen and each surface point includes distance indication coordinates, which are determined for each surface point based on the wavelength peak value generated by the measurement from the surface point along the wavelength measurement axis.

[0130] In some embodiments, the colorimetric range sensor system includes a colorimetric range sensor optical pen, an illumination source, a wavelength detector, and a processing unit. The illumination source is configured to generate multi-wavelength input light having an input spectral distribution input to the colorimetric range sensor optical pen. The wavelength detector includes a plurality of pixels having corresponding pixel positions distributed along a wavelength measurement axis of the wavelength detector. The colorimetric range sensor system is configured such that when the colorimetric range sensor optical pen is operably positioned relative to a surface to perform a measurement operation, the colorimetric range sensor optical pen inputs the input spectral distribution and outputs the corresponding radiation to the surface, and receives reflected radiation from the surface and outputs the reflected radiation to the wavelength detector. The processing unit is configured to determine distance indication data generated by the relative movement of the colorimetric range sensor optical pen about a nominal spherical calibration surface. The relative movement of the colorimetric range sensor optical pen is helical to perform a helical scan of a portion of the nominal spherical calibration surface, wherein the distance indication data is determined to correspond to the distance between the colorimetric range sensor optical pen and a surface point on the nominal spherical calibration surface during the helical scan. The distance calibration data is determined based on the distance indication data.

[0131] In some embodiments, the distance calibration data correlates distance indication coordinates with the measured distance. In some embodiments, the determination of the distance calibration data includes determining the position of the vertex of the nominal spherical calibration surface based at least in part on distance indication data obtained from a helical scan.

[0132] In some implementations, the distance calibration data includes distance indication coordinates along the wavelength measurement axis of the wavelength detector, which are related to the Z-axis measurement distance along the Z-axis to the surface being measured, wherein the Z-axis corresponds to the optical axis of the colorimetric range sensor optical pen.

[0133] In some implementations, distance calibration data is stored. The stored distance calibration data is then used to determine the measured distance from the colorimetric range sensor optical pen to the surface point based on the distance indication coordinates determined for the surface point based on the wavelength peak value generated from the measurement along the wavelength measurement axis from the surface point.

[0134] Although preferred embodiments of the present disclosure have been illustrated and described, many variations of the feature arrangements and sequences of operation shown and described will be apparent to those skilled in the art based on this disclosure. Various alternative forms can be used to implement the principles disclosed herein. Furthermore, the various embodiments described above can be combined to provide further embodiments. All U.S. patents mentioned in this specification are hereby incorporated herein by reference in their entirety. If it is necessary to employ concepts from various patents and applications to provide additional embodiments, aspects of the embodiments may be modified.

[0135] These and other changes may be made to the implementation based on the above detailed description. Generally, the terminology used in the following claims should not be construed as limiting the claims to the specific embodiments disclosed in the specification and claims, but should be construed as encompassing all possible embodiments and the full scope of the authorized equivalents of such claims.

Claims

1. A method for providing distance calibration data for a colorimetric range sensor system having a colorimetric range sensor optical pen coupled to a measuring machine, wherein the colorimetric range sensor optical pen is configured to focus different wavelengths at different distances of approach to a surface to be measured, the method comprising: arranging the colorimetric range sensor optical pen in a certain relationship relative to a spherical calibration object having a nominally spherical calibration surface; controlling the measuring machine to effect relative movement of the colorimetric range sensor optical pen about the nominally spherical calibration surface, wherein the relative movement of the colorimetric range sensor optical pen is in a spiral so as to perform a spiral scan of a portion of the nominally spherical calibration surface, wherein distance indicating data is determined corresponding to distances between the colorimetric range sensor optical pen and surface points on the nominally spherical calibration surface as the spiral scan is performed; and determining distance calibration data for the colorimetric range sensor system based on the distance indicating data.

2. The method of claim 1, wherein the determining of the distance calibration data includes determining a relative position of each surface point with respect to an apex of the nominally spherical calibration surface.

3. The method of claim 2, wherein the determining of the distance calibration data includes determining a position of the apex of the nominally spherical calibration surface and the relative position of each surface point with the distance indicating data collected during the spiral scan.

4. The method of claim 2, wherein the surface points on the nominally spherical calibration surface are each at a same nominal radius from a common center point of the spherical calibration object, and wherein the apex of the nominally spherical calibration surface is directly above the common center point and correspondingly has the same X and Y axis coordinates in a machine coordinate system of the measuring machine as the common center point.

5. The method of claim 2, wherein the relative position of each surface point with respect to the apex corresponds to a radial position of each surface point, wherein each radial position corresponds to a known difference between the apex and a Z axis coordinate in a machine coordinate system of the measuring machine for the surface point according to known geometric properties of the nominally spherical calibration surface.

6. The method of claim 5, wherein the known difference between the Z axis coordinates corresponds to at least a portion of a measured distance from the colorimetric range sensor optical pen to the surface point, and for each surface point, the distance indicating data includes a distance indicating coordinate determined for the surface point based on a wavelength peak resulting from a measurement along a wavelength measurement axis from the surface point, and wherein the determining of the distance calibration data includes relating the distance indicating coordinate of each surface point to a measured distance from the colorimetric range sensor optical pen to the surface point.

7. The method of claim 6, comprising storing the distance calibration data, wherein as part of a subsequent measurement of a surface point, a distance indicating coordinate is determined for the surface point based on a wavelength peak produced from a measurement of the surface point along the wavelength measurement axis, and the stored distance calibration data is used to determine a measured distance of the colorimetric range sensor optical pen to the measured surface point based on the measured distance in relation to the distance indicating coordinate determined by the stored distance calibration data.

8. The method of claim 6, wherein the wavelength measurement axis is a detector array of a wavelength detector of the colorimetric range sensor system.

9. The method of claim 2, wherein the colorimetric range sensor optical pen has a measurement range extending between a minimum measurement distance and a maximum measurement distance, and the positioning the colorimetric range sensor optical pen in the arrangement of the relationship relative to the spherical calibration object comprises positioning the colorimetric range sensor optical pen so that the minimum measurement distance is proximate the apex of the nominal spherical calibration surface of the spherical calibration object.

10. The method of claim 1, wherein to perform the spiral scan, wherein the surface points for which the distance indicating data is determined comprise at least 100 surface points.

11. The method of claim 1, wherein the controlling the measurement machine to effect the relative movement of the colorimetric range sensor optical pen about the nominal spherical calibration surface comprises maintaining a constant Z height of the colorimetric range sensor optical pen in a machine coordinate system of the measurement machine during performance of the spiral scan.

12. The method of claim 1, comprising: determining intensity peak data as an amount of light received by the colorimetric range sensor optical pen for different distances between the colorimetric range sensor optical pen and the nominal spherical calibration surface; and determining intensity calibration data based on the intensity peak data, wherein the distance indicating data is determined based at least in part on the intensity calibration data.

13. The method of claim 12, wherein: the determining intensity peak data comprises effecting the relative movement of the colorimetric range sensor optical pen for performing a sweep in a range of Z axis distances from the nominal spherical calibration surface while maintaining X axis and Y axis coordinates invariant in a machine coordinate system of the measurement machine, and capturing intensity peak data during the sweep; and the determining intensity calibration data comprises generating an intensity normalization calibration curve based on the captured intensity peak data.

14. The method of claim 12, wherein: the determining intensity peak data comprises capturing intensity peak data during the spiral scan; and the determining intensity calibration data comprises generating an intensity normalization calibration curve based on the captured intensity peak data.

15. A measurement system, comprising: a measurement machine comprising a motion controller; a chromatic range sensor system comprising a chromatic range sensor optical pen configured to focus different wavelengths at different distances proximate to a surface to be measured, wherein the chromatic range sensor optical pen is configured to be coupled to the measuring machine; a spherical calibration object comprising a nominally spherical calibration surface; wherein the measuring system is configured to: implement relative movement of the chromatic range sensor optical pen with respect to the nominally spherical calibration surface using the motion controller, wherein the relative movement of the chromatic range sensor optical pen is helical so as to perform a helical scan of a portion of the nominally spherical calibration surface, wherein distance indicating data is determined as corresponding to distances between the chromatic range sensor optical pen and surface points on the nominally spherical calibration surface as the helical scan is performed; and determine distance calibration data for the chromatic range sensor system based on the distance indicating data.

16. The measuring system of claim 15, wherein the determination of the distance calibration data comprises determining radial positions of each surface point relative to a position of an apex of the nominally spherical calibration surface, wherein each radial position corresponds to a distance between a corresponding surface point and the chromatic range sensor optical pen as measured from a geometric property of the nominally spherical calibration surface, wherein each distance is associated with a distance indicating coordinate determined for the corresponding surface point as part of determining the distance calibration data.

17. The measuring system of claim 15, wherein the measuring system is additionally configured to store the distance calibration data, subsequently perform a measurement process to determine a measured distance corresponding to a distance between the chromatic range sensor optical pen and a surface point on a surface, wherein the measurement process comprises determining a distance indicating coordinate for the surface point based on a wavelength peak produced from the measurement of the surface point along a wavelength measurement axis, and wherein the stored distance calibration data is used to correlate the distance indicating coordinate with a corresponding measured distance.

18. The measuring system of claim 15, wherein the distance indicating data corresponding to the distance between the chromatic range sensor optical pen and each surface point comprises a distance indicating coordinate determined for each surface point based on a wavelength peak produced from the measurement of the surface point along a wavelength measurement axis.

19. A chromatic range sensor system for use with a measuring machine and a calibration object having a nominally spherical calibration surface, the chromatic range sensor system comprising: a chromatic range sensor optical pen configured to focus different wavelengths at different distances proximate to a surface to be measured; an illumination source configured to generate a multi-wavelength input light comprising an input spectral distribution of input light to the chromatic range sensor optical pen; a wavelength detector comprising a plurality of pixels having respective pixel positions distributed along a wavelength measurement axis of the wavelength detector, wherein the colorimetric range sensor system is configured such that when the colorimetric range sensor optical pen is operably positioned relative to a surface to perform a measurement operation, the colorimetric range sensor optical pen inputs the input spectral distribution and outputs corresponding radiation to the surface, and receives reflected radiation from the surface and outputs the reflected radiation to the wavelength detector; and a processing portion configured to: determine distance-indicative data resulting from relative movement of the colorimetric range sensor optical pen with respect to the nominally spherical calibration surface, wherein the relative movement of the colorimetric range sensor optical pen is in a spiral so as to perform a spiral scan of a portion of the nominally spherical calibration surface from which the distance-indicative data is determined as corresponding to a distance between the colorimetric range sensor optical pen and a surface point on the nominally spherical calibration surface while performing the spiral scan; and determine distance calibration data based on the distance-indicative data.

20. The colorimetric range sensor system of claim 19, wherein the distance calibration data relates distance-indicative coordinates to measured distances.

21. The colorimetric range sensor system of claim 19, wherein the determination of the distance calibration data includes determining a location of an apex of the nominally spherical calibration surface based at least in part on the distance-indicative data obtained from the spiral scan.

22. The colorimetric range sensor system of claim 19, wherein the distance calibration data includes distance-indicative coordinates along the wavelength measurement axis of the wavelength detector that are related to Z-axis measured distances to a measured surface along a Z-axis, wherein the Z-axis corresponds to an optical axis of the colorimetric range sensor optical pen.

23. The colorimetric range sensor system of claim 22, wherein the distance calibration data is stored and subsequently used to determine a measured distance between the colorimetric range sensor optical pen and a surface point based on a distance-indicative coordinate determined for the surface point based on a wavelength peak resulting from a measurement of the surface point along the wavelength measurement axis.

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