Systems and methods for gas mixing within the sensor field of view of a video extensometer.

Abstract

The disclosed example video extensometer includes: an optical sensor having a field of view; and a fan disposed within a housing and adjacent to the optical sensor and configured to mix gas within the field of view of the optical sensor. The housing has an inlet pointing toward and adjacent to the field of view of the optical sensor to draw gas from a region within the field of view of the optical sensor, and the housing has an outlet configured to direct gas blown by the fan into the field of view of the optical sensor to mix the gas within the field of view of the optical sensor.

Description

Related applications

[0001] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 739,958, filed December 30, 2024, entitled "Systems and methods for gas mixing within a sensor field of view for a video extensometer". The entire contents of U.S. Provisional Patent Application Serial No. 63 / 739,958 are expressly incorporated herein by reference. Technical Field

[0002] This disclosure relates to materials testing systems, and more specifically to systems and methods for gas mixing within the sensor field of view of a video extensometer. Background Technology

[0003] Camera-based vision systems have been implemented as part of materials testing systems to measure sample strain. These systems collect one or more images of the sample being tested, synchronized with other signals of interest in the test, such as sample load, machine actuator / crosshead displacement, etc. As the test proceeds, the images of the test sample can be analyzed to locate and track specific features of the sample. Changes in the position of such features (such as the width of the sample) allow for the calculation of local sample deformation, and consequently, the calculation of sample strain. Summary of the Invention

[0004] A system and method for gas mixing within the sensor field of view of a video extensometer are disclosed, substantially as illustrated and described in conjunction with at least one of the accompanying drawings. Attached Figure Description

[0005] The benefits and advantages of this disclosure will become more apparent to those skilled in the art after reading the following detailed description and accompanying drawings, in which: Figure 1 This is a block diagram of an example extensometer system based on various aspects of this disclosure.

[0006] Figure 2 It is used in Figure 1 Example test samples were measured using the extensometer system.

[0007] Figure 3 It can be used for implementation Figure 1 A perspective view of an example imaging device, which includes a fan for reducing imaging noise caused by turbulence in the field of view of the imaging device.

[0008] Figure 4 yes Figure 3 A side-view elevation view of an example imaging device.

[0009] Figure 5 yes Figure 3 A partial exploded view of an example imaging device.

[0010] Figure 6A and Figure 6B yes Figures 3 to 5 A 3D view of an example fan housing.

[0011] Figure 7A yes Figure 3 Example manifold top view, front view, left view, stereoscopic view.

[0012] Figure 7B yes Figure 3 Example manifold: top-down, rear-view, and right-view stereoscopic diagram.

[0013] Figure 8 yes Figure 1 A block diagram of an example implementation of an extensometer system.

[0014] The accompanying drawings are not necessarily drawn to scale. Where appropriate, similar or identical reference numerals are used to refer to similar or identical parts. Detailed Implementation

[0015] Video extensometer systems can be sensitive to changes in the environment between the imaging device and the test sample. For example, the refractive index of the gas (e.g., air) within the field of view of both the imaging device and the test sample can affect the imaging device's measurements. When the refractive index of the gas and / or other environmental properties change during the imaging device's measurement, the results may be affected by noise or other sources of error. Some conventional video extensometer systems attempt to control the environment within the field of view by including the gas within it to reduce variation and / or by inducing a vacuum in at least a portion of the field of view. Other conventional video extensometer systems provide controlled airflow over a portion of the field of view in an open environment.

[0016] The disclosed example systems and methods improve the uniformity of gas in the field of view of an imaging device by inducing airflow over a large portion of the field of view between the video extensometer imaging device and the test sample. In some examples, one or more fans include inlets directed toward a portion of the field of view adjacent to (e.g., closest to) the optical sensor of the imaging device. In some such examples, the inlets are configured to generate a gas flow that sweeps across the lens of the optical sensor, which also provides active cooling to the imaging device. In some examples, the fan further includes an outlet that directs the gas flow received from the inlet toward the field of view and toward the test sample to produce uniform gas characteristics, thereby reducing imaging noise at the optical sensor. The fan may further include secondary outlets that direct the gas flow further toward the field of view than the main outlet to improve the gas flow on additional portions of the field of view that may not experience as much gas flow from the fan inlets and / or the main outlet.

[0017] In some of the disclosed examples, the imaging apparatus further includes a manifold for further controlling the gas flow within the field of view of the optical sensor. The manifold may include a gas inlet for drawing gas through the field of view of the optical sensor, and a gas outlet corresponding to a gas inlet of a fan.

[0018] As used herein, a materials testing system (including materials testing systems that apply tension, compression, and / or torsion) includes one or more components that induce displacement and / or load bearing to apply and / or measure stress on a test sample. In some examples, a video extensometer system is used for sample strain testing, which may include one or more of the following: acquiring high-resolution images, providing the images to an image processor, analyzing the images to identify one or more sample characteristics corresponding to displacement or strain values, and generating output corresponding to those characteristics. In some examples, the identified characteristics (e.g., width) from one or more acquired images are compared with one or more sources (e.g., a threshold list) or with previously acquired images (i.e., prior to the test). In some examples, the values ​​of the identified characteristics may be applied to one or more algorithms to generate output corresponding to displacement or strain values ​​associated with the test sample.

[0019] In the disclosed examples, the extensometer may include an external machine vision imaging device connected to a processing system or computing platform and / or video processing hardware, and use software and / or hardware to convert data from the camera into electrical signals or a software interface with a compatible materials testing system.

[0020] As disclosed herein, camera-based image capture (e.g., vision or video) systems are implemented in materials testing systems to measure strain on test specimens. Such systems collect multiple images of the specimen being tested (i.e., during the testing process), synchronized with other signals of interest in the test (e.g., specimen load, machine actuator / beam displacement, etc.). As the test progresses, the images of the specimen are analyzed by algorithms (e.g., in real-time and / or post-test) to locate and track specific specimen properties. For example, changes in the location, size, shape, etc., of such properties allow for the calculation of deformation of the test specimen, which in turn allows for the analysis and calculation of specimen strain.

[0021] According to various aspects of this disclosure, an example video extensometer includes: an optical sensor having a field of view; and a fan disposed within a housing and adjacent to the optical sensor and configured to mix gas within the field of view of the optical sensor, the housing having an inlet pointing toward and adjacent to the field of view of the optical sensor to draw gas from a region within the field of view of the optical sensor, and the housing having an outlet configured to direct gas blown by the fan into the field of view of the optical sensor to mix the gas within the field of view of the optical sensor.

[0022] In some example video extensometers, the housing includes a secondary outlet pointing adjacent to the field of view of the optical sensor and configured to direct at least a portion of the gas blown by a fan toward the portion of the field of view adjacent to the optical sensor. Some example video extensometers further include a second fan disposed within a second housing and adjacent to the optical sensor, and configured to mix the gas within the field of view of the optical sensor. The second housing has a second inlet pointing toward a region adjacent to the optical sensor within the field of view of the optical sensor to draw gas from that region. The housing also has a second outlet configured to direct the gas blown by the second fan to mix the gas within that field of view. In some example video extensometers, the first and second fans are positioned on opposite sides of the optical sensor.

[0023] In some example video extensometers, in the mounting arrangement, a fan is positioned above the optical sensor, and a second fan is positioned below the optical sensor. In some example video extensometers, the second housing includes a secondary outlet pointing toward the field of view adjacent to the optical sensor, and is configured to direct at least a portion of the gas blown by the second fan toward the portion of the field of view adjacent to the optical sensor.

[0024] In some example video extensometers, the fan is configured to uniformly mix the gas occupying the area between the optical sensor and the test sample within the field of view of the optical sensor. In some example video extensometers, the fan is positioned at least partially toward the test sample relative to the optical sensor. In some example video extensometers, the gas is air. In some example video extensometers, the inlet and outlet are each at least as wide as the test sample.

[0025] In some example video extensometers, the center of the inlet is positioned closer to the rear end of the housing than the front end, and the front end of the housing is closer to the test sample than the rear end. In some example video extensometers, the inlet is configured such that at least a portion of the gas is drawn through a lens of the optical sensor before entering the housing. In some example video extensometers, a fan is configured to mix the gas along the entire length of the field of view between the optical sensor and the test sample. Some example video extensometers further include a manifold configured to direct gas into the fan inlet, with at least a portion of the field of view extending through the manifold.

[0026] Now refer to the attached diagram, Figure 1 This is an example extensometer system 10, used to measure changes in one or more properties of a test sample 16 undergoing mechanical property testing. The example extensometer system 10 can be connected to a testing system 33, for example, capable of performing mechanical tests on the test sample 16. The extensometer system 10 can measure and / or calculate changes in the test sample 16 under conditions such as compressive strength testing, tensile strength testing, shear strength testing, flexural strength testing, flexural strength testing, tear strength testing, peel strength testing (e.g., adhesive strength), torsional strength testing, and / or any other compression and / or tensile tests. Additionally or alternatively, the extensometer system 10 can perform dynamic testing.

[0027] According to the disclosed examples, the extensometer system 10 may include a test system 33 for manipulating and testing the test sample 16, and / or a computing device 32 communicatively coupled to the test system 33, a light source, and / or an imaging device, such as... Figure 8 As further shown, the test system 33 applies a load to the test sample 16 and measures the mechanical properties of the test sample 16, such as the displacement of the test sample 16 and / or the force applied to the test sample 16.

[0028] The extensometer system 10 includes a remote light source and / or an integrated light source 14 (e.g., an LED array) for illuminating the test sample 16 and / or a reflective back screen 18. The extensometer system 10 includes a computing device 32 (see also...). Figure 8The light source 14 and imaging device 12 are configured to emit and receive at infrared (IR) wavelengths; however, other wavelengths are similarly applicable. In some examples, one or both of the light source 14 or imaging device 12 include one or more filters (e.g., polarizing filters) and one or more lenses. In some examples, a calibration routine (e.g., a two-dimensional calibration routine) is performed to identify one or more characteristics of the test sample 16, additionally using one or more markings 20 (including marking patterns).

[0029] In some examples, the back screen 18 is configured to reflect light from the light source 14 back to the imaging device 12. For example, the surface of the back screen 18 may be configured with properties that enhance reflection and / or direct reflected light toward the imaging device. Properties may include the shape of the back screen 18 (e.g., a parabolic configuration) and / or treatments that increase reflection (e.g., the application of a cornerstone prism reflector, reflective materials, etc.). Additionally or alternatively, a filter 30 may be arranged and / or applied to the surface to increase the amount of reflection and / or direct reflected light in a desired direction and / or wavelength. In some examples, the filter 30 is configured as a collimating filter to provide as much reflected light as possible toward the imaging device 12 and away from other nearby components.

[0030] In the disclosed example, the computing device 32 can be used to configure the test system 33, control the test system 33, and / or receive measurement data (e.g., transducer measurements such as force and displacement) and / or test results (e.g., peak force, fracture displacement, etc.) from the test system 33 for processing, display, reporting, and / or any other desired purpose. The extensometer system 10 connects to the test system 33 and software using standard interfaces including Ethernet, analog, encoder, or SPI. This allows the device to be plugged into and used by existing systems without requiring specialized integration software or hardware. The extensometer system 10 provides axial and transverse encoder or analog information to the test system 33 in real time. Example: The extensometer system 10 and material testing machine 190 exchange real-time test data (including elongation / strain data) with the computing device 32, which can be configured via wired and / or wireless communication channels. The extensometer system 10 provides measurement and / or calculation results from the elongation / strain data captured from the test sample 16 being tested in the test system 33, which in turn provides stress and elongation / strain data to the computing device 32.

[0031] As disclosed herein, the captured images are input from the imaging device to the computing device 32, where one or more algorithms and / or lookup tables are used to calculate the elongation / strain values ​​of multiple axes of the test sample 16 (i.e., changes in inter-target distances or percentage changes, such as those calculated by image monitoring of markers 20 attached to the test sample 16). After calculation, the data can be stored in memory or output to a network and / or one or more display devices, I / O devices, etc. (see also...) Figure 8 ).

[0032] Figure 2 It is used in Figure 1 An example test sample 16 is used for measurement in the extensometer system 10. For example, one or more markings are applied to the surface 28 facing the light source 14 and the imaging device 12. The fixture section 26 is configured to be placed in the test system 33 (see also...). Figure 8 The force is applied to the test sample 16 within the clamps and forces it onto the test sample 16. For example, a cross member loader applies force to the test sample 16 while the clamps grip or otherwise attach the test sample 16 to the test system 33. A force applicator (such as a motor) moves the crossbeam relative to the frame to apply force to the test sample 16, as indicated by the double arrow 34. The force 34, which pulls the clamp sections 26 apart from each other, can elongate the test sample 16, causing a mark to move from a first position 20A to a second position 20B. Additionally or alternatively, the mark can change shape or size, which can also be measured by the computing device 32 based on captured images. The force 34 can also move the edge of the test sample from a first position 22A to a second position 22B. For example, in the first or initial position, the edge has a width 24A, which decreases to a width 24B when the force 34 is applied.

[0033] Based on the captured images, the computing device 32 is configured to perform an elongation / strain measurement process. For example, to detect elongation / strain on test sample 16, the computing device 32 monitors images provided via imaging device 12. When the computing device 32 detects a change in the relative position between two or more markers and / or edges of test sample 16 (e.g., compared to the initial position when the beam begins to move), the computing device 32 measures the amount of change to calculate the elongation and / or strain on test sample 16. As disclosed herein, the markers are configured to reflect light from a light source to the camera, while a back screen reflects light to construct a dark outline for edge analysis. In some examples, the extensometer system 10 is configured to perform an optical width measurement of the opaque test sample 16.

[0034] Figure 3 It can be used for implementation Figure 1 An example three-dimensional view of imaging device 300 of imaging device 12. Figure 4 yes Figure 3The example imaging device 300 is shown in a side elevation view. As described in more detail below, the example imaging device 300 includes a fan 302 for reducing imaging noise caused by turbulence in the field of view of the imaging device 300.

[0035] Figure 3 The imaging device 300 includes two fans 302a and 302b, an optical sensor 304, and a sensor housing 306. The sensor housing 306 houses the optical sensor 304, as well as image processing circuitry, power supply circuitry, and / or other components for performing imaging using the optical sensor 304. The sensor housing 306 can further mount the imaging device 300 to a support structure for positioning the optical sensor 304 relative to the test sample 16.

[0036] Optical sensor 304 has a field of view 308. For material testing, the optical sensor 304 is oriented such that the test sample 16 is positioned within the field of view 308 of the optical sensor 304. The volume between the optical sensor 304 and the test sample 16 is typically filled with a gas, such as ambient atmosphere (e.g., air). Turbulence of the gas within the field of view can cause noise in the image captured using the optical sensor 304 due to differences in refractive index, for example, due to variations in temperature, humidity, and / or density. Imaging noise can reduce the accuracy of measurement results.

[0037] To improve the uniformity of gas within the field of view, the example imaging device 300 includes fans 302a, 302b to generate a substantially uniform and / or homogeneous flow of gas (e.g., air) within the field of view 308 of the optical sensor 304. The example fans 302a, 302b are disposed within respective fan housings 310a, 310b, which are attached to the sensor housing 306. Figure 5 yes Figure 3 A partial exploded view of an example imaging device 300. (See example image.) Figure 5 As shown, fans 302a and 302b are positioned within fan housings 310a and 310b to generate corresponding airflows through fan housings 310a and 310b. Figures 3 to 5 In the example, fans 302a and 302b are positioned on opposite sides of the optical sensor 304 in terms of mounting orientation, such as on the top and bottom of the optical sensor 304.

[0038] The fan housings 310a and 310b each include an outlet 312 to guide the gas blown by the respective fans 302a and 302b toward the field of view 308 of the optical sensor 304. Figure 6A and Figure 6B yes Figures 3 to 5 3D views of example fan housings 310a and 310b. Figure 3The fan housings 310a and 310b may have the same structure, wherein fan housing 310a is oriented inverted relative to fan housing 310b, such that the inlet of fan housings 310a and 310b is closer to the optical sensor 304, and the external inlet 316 is farther away from the optical sensor 304. Additionally, the orientation of each of the fan housings 310a and 310b and the outlet 312 may be configured to be at least partially aligned with the field of view 308.

[0039] exist Figures 3 to 6B In the example, fan housings 310a, 310b may include one or more secondary outlets 326 configured to direct gas blown by fans 302a, 302b toward a portion of the field of view 308 adjacent to the optical sensor 304. The secondary outlets 326 may direct gas partially toward the optical sensor 304 and / or partially toward the test sample.

[0040] Each of the fan housings 310a and 310b further includes an inlet 314 pointing towards the field of view 308. Fans 302a and 302b receive gas via the inlet 314 and exhaust gas via the outlet 312. Figure 3 and Figure 4 In the examples, fans 302a and 302b are positioned adjacent to optical sensor 304. In some examples, positioning fans 302a and 302b adjacent to optical sensor 304 involves positioning fans 302a and 302b as close as practically achievable to optical sensor 304 without interfering with field of view 308. Additionally or alternatively, fans 302a and 302b are positioned adjacent to optical sensor 304 by being sufficiently close to it to allow gas to sweep across the lens of optical sensor 304 into inlet 314 and / or to cause gas movement on the lens of optical sensor 304 by drawing gas into inlet 314. For example, inlet 314 (e.g., the center of inlet 314) is positioned closer to the rear end of fan housings 310a and 310b than to the front end of fan housings 310a and 310b (the front end of fan housings 310a and 310b is closer to test sample 16 than the rear end of fan housings 310a and 310b). By configuring inlet 314 to receive gas from the volume surrounding optical sensor 304, example fans 302a, 302b improve the uniformity of gas over a larger portion of the field of view 308 to further reduce imaging noise. Additionally, the gas sweeping across the lens of optical sensor 304 improves the cooling of optical sensor 304.

[0041] The widths of the example gas outlet 312 and the example gas inlet 314 are at least the width of the field of view 308 of the optical sensor 304. However, in other examples, the widths of the gas outlet 312 and / or the gas inlet 314 can be configured to obtain desired gas flow characteristics.

[0042] Example fan housings 310a, 310b include an additional external inlet 316 that can draw gas into fans 302a, 302b. In some examples, inlet 314 and external inlet 316 are configured to ensure that the airflow received through inlet 314 is sufficient to mix the gas within the volume closest to optical sensor 304.

[0043] In order to control the gas flow near the optical sensor 304, the example imaging device 300 may further include a manifold 318 disposed between fans 302a and 302b. Figure 7A yes Figure 3 Example manifold 318 top-view, front-view, and left-view stereoscopic diagrams. Figure 7B yes Figure 3 Example manifold 318: rear-view and right-view stereoscopic view. From Figure 4 and Figure 5 Manifold 318 is omitted to improve the visibility of fan housings 310a, 310b. Example manifold 318 includes gas inlet ports 320a, 320b, an observation port 322, and gas outlet ports 324a, 324b. Gas inlet ports 320a, 320b allow gas to enter manifold 318. Observation port 322 prevents manifold 318 from obstructing or blocking the field of view 308. Observation port 322 also allows gas to enter manifold 318, which can further improve gas mixing in front of optical sensor 304 and / or promote cooling of optical sensor 304.

[0044] Gas outlets 324a and 324b allow gas to flow from manifold 318 and are aligned with inlets 314 of fans 302a and 302b. The positions of gas inlets 320a and 320b and gas outlets 324a and 324b can be configured to promote uniform movement and / or mixing of gas within manifold 318, thereby improving gas uniformity within field of view 308 and reducing imaging noise. Additionally or alternatively, the positions of gas inlets 320a and 320b and gas outlets 324a and 324b can be configured to facilitate scanning of the lens of optical sensor 304 by gas movement through manifold 318.

[0045] Example fan housings 310a, 310b are attached to sensor housing 306, for example, by fasteners and / or brackets. Fans 302a, 302b may be attached to sensor housing 306, or to fan housings 310a, 310b, which are attached to sensor housing 306.

[0046] Although Figures 3 to 5 Examples include two fans 302a and 302b, but in other examples, one fan or three or more fans may be provided to mix the gas in the field of view 308.

[0047] Figure 8 yes Figure 1 A block diagram of an example extensometer system 10. (See attached diagram.) Figure 1 As shown, the extensometer system 10 includes a test system 33 and a computing device 32. Example computing device 32 may be a general-purpose computer, laptop computer, tablet computer, mobile device, server, all-in-one computer, and / or any other type of computing device. Figure 8 The computing device 32 includes a processor 802, which may be a general-purpose central processing unit (CPU). In some examples, the processor 802 may include one or more dedicated processing units, such as an FPGA, a RISC processor with an ARM core, a graphics processing unit, a digital signal processor, and / or a system-on-a-chip (SoC). The processor 802 executes machine-readable instructions 804, which may be stored locally at the processor (e.g., in the included cache or SoC), in random access memory 806 (or other volatile memory), in read-only memory 808 (or other non-volatile memory such as flash memory), and / or in a mass storage device 810. Example mass storage device 810 may be a hard disk drive, a solid-state drive, a hybrid drive, a RAID array, and / or any other mass data storage device. A bus 812 enables communication between the processor 802, RAM 806, ROM 808, mass storage device 810, network interface 814, and / or input / output interface 816.

[0048] Example network interface 814 includes hardware, firmware, and / or software to connect computing device 32 to communication network 818 (such as the Internet). For example, network interface 814 may include IEEE 802.X compliant wireless and / or wired communication hardware for transmitting and / or receiving communications.

[0049] Figure 8Example I / O interface 816 includes hardware, firmware, and / or software for connecting one or more input / output devices 820 to processor 802, thereby providing input to and / or output to processor 802. For example, I / O interface 816 may include a graphics processing unit for interfacing with a display device, a universal serial bus port for interfacing with one or more USB-compatible devices, FireWire, fieldbus, and / or any other type of interface. Example extensometer system 10 includes a display device 824 (e.g., an LCD screen) coupled to I / O interface 816. Other example I / O devices 820 may include a keyboard, keypad, mouse, trackball, pointing device, microphone, audio speaker, display device, optical media driver, multi-touch screen, gesture recognition interface, magnetic media driver, and / or any other type of input and / or output device.

[0050] The computing device 32 can access the non-transitory machine-readable medium 822 via the I / O interface 816 and / or the I / O device 820. Figure 8 Examples of machine-readable media 822 include: optical discs (e.g., compact discs, DVDs, Blu-ray discs, etc.), magnetic media (e.g., floppy disks), portable storage media (e.g., portable flash drives, secure digital (SD) cards, etc.) and / or any other type of removable and / or installable machine-readable media.

[0051] The extensometer system 10 further includes a test system 33 connected to the computing device 32. Figure 8 In some examples, test system 33 is connected to a computing device via I / O interface 816, such as via a USB port, Thunderbolt port, FireWire (IEEE 1394) port, and / or any other type of serial or parallel data port. In some examples, test system 33 is connected directly to network interface 814 and / or to I / O interface 816 via wired or wireless connections (e.g., Ethernet, Wi-Fi, etc.) or via network 818.

[0052] Test system 33 includes a frame 828, a load sensor 830, a displacement transducer 832, a cross member loader 834, a material clamping device 836, and a control processor 838. The frame 828 provides rigid structural support to the other components of test system 33 that perform the test. The load sensor 830 measures the force applied to the test material by the cross member loader 834 via the clamp 836. The cross member loader 834 applies force to the test material, while the material clamping device 836 (also called a clamp) holds the test material or otherwise attaches the test material to the cross member loader 834. An example cross member loader 834 includes a motor 842 (or other actuator) and a crossbeam 844. As used herein, a "crossbeam" refers to a component of a material testing system that applies directional (axial) and / or rotational forces to a sample. A material testing system may have one or more crossbeams, and the crossbeams(s) ... A crossbeam 844 connects the material fixing device 836 to the frame 828, and a motor 842 moves the crossbeam relative to the frame to position the material fixing device 836 and / or apply force to the material being tested. Example actuators that can be used to provide force and / or movement of components of the extensometer system 10 include electric motors, pneumatic actuators, hydraulic actuators, piezoelectric actuators, relays, and / or switches.

[0053] While the example test system 33 uses a motor 842 (such as a servo motor or a direct-drive linear motor), other systems can use different types of actuators. For example, depending on the system requirements, hydraulic actuators, pneumatic actuators, and / or any other type of actuator can be used.

[0054] Example fixture 836 includes a clamping plate, grippers, or other type of securing device, depending on the mechanical property being tested and / or the material being tested. Fixture 836 can be manually configured, controlled via manual input, and / or automatically controlled by a control processor 838. The beam 844 and fixture 836 are operator-accessible components.

[0055] The extensometer system 10 may further include one or more control panels 850, which include one or more mode switches 852. Mode switches 852 may include buttons, switches, and / or other input devices located on the operator's control panel. For example, mode switches 852 may include buttons that control motor 842 to jog (e.g., position) the crossbeam 844 at a specific location on the frame 828, switches (e.g., foot switches) that control clamp actuator 846 to close or open pneumatic clamp 848, and / or any other input device controlling the operation of the test system 33.

[0056] Example control processor 838 communicates with computing device 32 to receive test parameters from computing device 32 and / or report measured values ​​and / or other results to computing device 32. For example, control processor 838 may include one or more communication or I / O interfaces to enable communication with computing device 32. Control processor 838 may control the cross member loader 834 to increase or decrease the applied force, control the fixing device(s) 836 to grasp or release the test material, and / or receive measurement results from displacement transducer 832, load sensor 830, and / or other transducers.

[0057] Example control processor 838 is configured to perform an elongation / strain measurement process while test sample 16 is being tested in test system 33. For example, to detect elongation / strain on test sample 16, control processor 838 monitors images provided via imaging device 12. When control processor 838 detects a change in the positioning and / or location of edge 22 of test sample 16 (e.g., compared to its initial position when movement of beam 844 begins), control processor 838 measures the amount of change to calculate elongation and / or strain on test sample 16. For example, real-time video provided by imaging device 12 captures the absolute position of edge 22 and monitors their relative movement over multiple images to calculate elongation / strain in real time. Stress and strain data are exchanged between extensometer system 10, test system 33, and computing device 32, and are typically arranged and displayed via display device 824.

[0058] The method and system can be implemented using hardware, software, and / or a combination of hardware and software. The method and / or system can be implemented centrally on at least one computing system or distributedly across several interconnected computing systems with different components. Any kind of computing system or other device suitable for performing the methods described herein is appropriate. A typical combination of hardware and software may include a general-purpose computing system having a program or other code that, when loaded and executed, controls the computing system to perform the methods described herein. Another typical implementation may include an application-specific integrated circuit or chip. Some implementations may include a non-transitory machine-readable (e.g., computer-readable) medium (e.g., a flash drive, optical disc, magnetic disk, etc.) storing one or more lines of machine-executable code that enables the machine to perform the processes described herein. As used herein, the term "non-transitory machine-readable medium" is defined to include all types of machine-readable storage media and excludes propagated signals.

[0059] As used herein, the terms “circuit” and “circuit system” refer to physical electronic components (i.e., hardware) and any software and / or firmware (“code”) that can configure, be executed by, and / or otherwise associate with the hardware. As used herein, for example, a particular processor and memory may constitute a first “circuit” when executing a first line or more of code, and a second “circuit” when executing a second line or more of code. As used herein, “and / or” refers to any one or more of the multiple items in the list connected by “and / or”. As an example, “x and / or y” refers to any element in the three-element set {(x), (y), (x, y)}. In other words, “x and / or y” means “one or both of x and y”. As another example, “x, y and / or z” refers to any element in the seven-element set {(x), (y), (z), (x, y), (x, z), (y, z), (x, y, z)}. In other words, “x, y and / or z” means “one or more of x, y and z”. As used herein, the term "exemplary" means used as a non-limiting example, instance, or illustration. As used herein, the terms "for example" and "for instance" refer to one or more lists of non-limiting examples, instances, or illustrations. As used herein, a circuit system is "operable" to perform a function when it includes the hardware and code necessary to perform that function, if necessary, regardless of whether the performance of that function is disabled or not enabled (e.g., through user-configurable settings, factory settings, etc.).

[0060] Although this method and / or system has been described with reference to certain embodiments, those skilled in the art will understand that various changes and equivalents can be made without departing from the scope of this method and / or system. Furthermore, many modifications can be made to adapt specific situations or materials to the teachings of this disclosure without departing from the scope of this disclosure. For example, the systems, blocks, and / or other components of the disclosed examples can be combined, divided, rearranged, and / or otherwise modified. Therefore, this method and / or system is not limited to the specific embodiments disclosed. Rather, this method and / or system will include all embodiments that fall within the scope of the appended claims, both literally and according to the principle of equivalents.

Claims

1. A video extensometer, comprising: An optical sensor having a field of view; as well as A fan is disposed within a housing and adjacent to the optical sensor and configured to mix gas within the field of view of the optical sensor. The housing has an inlet that points toward and is adjacent to the field of view of the optical sensor to draw gas from a region within the field of view of the optical sensor, and the housing has an outlet configured to guide the gas blown by the fan into the field of view of the optical sensor to mix the gas within the field of view of the optical sensor.

2. The video extensometer as described in claim 1, wherein, The housing includes a secondary outlet pointing toward the field of view adjacent to the optical sensor, and is configured to direct at least a portion of the gas blown by the fan toward the portion of the field of view adjacent to the optical sensor.

3. The video extensometer of claim 1, further comprising a second fan disposed within a second housing and adjacent to the optical sensor, and configured to mix the gas within the field of view of the optical sensor, the second housing having a second inlet pointing toward the region adjacent to the optical sensor within the field of view of the optical sensor to draw the gas from the region within the field of view of the optical sensor, and the housing having a second outlet configured to direct the gas blown by the second fan to mix the gas within the field of view.

4. The video extensometer as described in claim 3, wherein, The first fan and the second fan are positioned on opposite sides of the optical sensor.

5. The video extensometer as described in claim 3, wherein, In the installation arrangement, the fan is located above the optical sensor, and the second fan is located below the optical sensor.

6. The video extensometer as described in claim 3, wherein, The second housing includes a secondary outlet pointing toward the field of view adjacent to the optical sensor and configured to direct at least a portion of the gas blown by the second fan toward the portion of the field of view adjacent to the optical sensor.

7. The video extensometer as described in claim 1, wherein, The fan is configured to uniformly mix the gas located in the region between the optical sensor and the test sample, which occupies the field of view of the optical sensor.

8. The video extensometer as described in claim 1, wherein, The fan is positioned at least partially toward the test sample relative to the optical sensor.

9. The video extensometer as described in claim 1, wherein, The gas in question is air.

10. The video extensometer as claimed in claim 1, wherein, The inlet and the outlet are each at least as wide as the test sample.

11. The video extensometer as claimed in claim 1, wherein, The center of the inlet is positioned closer to the rear end of the housing than to the front end, which is closer to the test sample than the rear end.

12. The video extensometer as claimed in claim 1, wherein, The inlet is configured such that at least a portion of the gas is drawn through the lens of the optical sensor before it enters the housing.

13. The video extensometer as claimed in claim 1, wherein, The fan is configured to mix the gas over the entire length of the field of view between the optical sensor and the test sample.

14. The video extensometer of claim 1, further comprising a manifold configured to direct the gas into the inlet of the fan, wherein at least a portion of the field of view extends through the manifold.

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