System and method for gas mixing within the sensor field of view of a video extensometer.

Abstract

Providing video extensometers. [Solution] The illustrated video extensometer disclosed includes a photosensor having a field of view and a fan positioned adjacent to the photosensor within a housing and configured to mix gases within the photosensor's field of view, the housing having an intake port adjacent to the photosensor and directed toward the photosensor's field of view, which draws gases from an area within the photosensor's field of view, and the housing having an exhaust port configured to direct gases blown by the fan toward the photosensor's field of view and mix gases within the photosensor's field of view.

Description

Technical Field

[0001] [Related Applications] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 739,958, entitled "SYSTEMS AND METHODS FOR GAS MIXING WITHIN A SENSOR FIELD OF VIEW FOR VIDEO EXTENSOMETERS," filed on December 30, 2024. The entire content of this U.S. Provisional Patent Application No. 63 / 739,958 is hereby incorporated by reference and made a part of this specification.

[0002] The present disclosure relates to a material testing system, and more particularly, to systems and methods for gas mixing within a sensor field of view of a video extensometer.

Background Art

[0003] Camera-based vision systems have been implemented as part of a material testing system for measuring sample strain. These systems collect one or more images of a test sample. These images are synchronized with other signals relevant to the test, such as sample load, displacement of a mechanical actuator / crosshead, etc. The images of the test sample are analyzed to identify and track the location of specific features of the sample as the test progresses. By the change in the location of such features, such as the width of the sample, it becomes possible to calculate local sample deformation and further calculate sample strain.

Summary of the Invention

[0004] Systems and methods for gas mixing within a sensor field of view of a video extensometer are disclosed as being substantially illustrated by at least one of the figures and described with respect to at least one of the figures.

[0005] The benefits and advantages of the present disclosure will be readily apparent to those skilled in the art after considering the following detailed description and the accompanying drawings. [Brief explanation of the drawing]

[0006] [Figure 1] This is a block diagram of an example of an extension meter system according to the embodiments of this disclosure.

[0007] [Figure 2] Figure 1 shows an example test sample for measurement in the extensometer system.

[0008] [Figure 3] This is a perspective view of an exemplary imaging device that can be used to implement the imaging device shown in Figure 1, including a fan that reduces imaging noise caused by turbulence in the field of view of the imaging device.

[0009] [Figure 4] Figure 3 is a side view of the example imaging device.

[0010] [Figure 5] Figure 3 is a partially exploded view of the imaging device shown in the example.

[0011] [Figure 6A] Figures 3 to 5 are perspective views of the fan housings shown as examples. [Figure 6B] Figures 3 to 5 are perspective views of the fan housings shown as examples.

[0012] [Figure 7A] Figure 3 is a front view from the upper left of the example manifold.

[0013] [Figure 7B] This is a perspective view of the lower right rear of the manifold shown in the example in Figure 3.

[0014] [Figure 8] Figure 1 is a block diagram of an example embodiment of the extensometer system. [Modes for carrying out the invention]

[0015] The drawings are not necessarily to exact scale. Where appropriate, similar or identical reference numbers are used to refer to similar or identical components.

[0016] Video extensometer systems can be sensitive to changes in the environment between the imaging device and the test specimen. For example, the refractive index of a gas (e.g., air) within the field of view of the imaging device and the test specimen affects measurements by the imaging device. If the refractive index of the gas and / or other properties of the environment change during measurements by the imaging device, the measurements may be subject to errors from noise or other sources of error. Some conventional video extensometer systems attempt to control the environment within the field of view by confining a gas within the field of view and / or by inducing a vacuum state in at least a portion of the field of view to reduce changes. Other conventional video extensometer systems provide a controlled airflow in an open environment across multiple portions of the field of view.

[0017] The disclosed exemplary systems and methods improve gas uniformity in a field of view by inducing airflow across a larger portion of the imaging device's field of view between the video extensometer imaging device and the test specimen. In some examples, one or more fans include an intake (inlet) directed toward a portion of the field of view adjacent to (e.g., closest to) the imaging device's photosensor. In some such examples, the intake is configured to generate a gas flow that sweeps across the photosensor's lens. This gas flow also provides active cooling of the imaging device. In some examples, the fan(s) further include an exhaust (outlet) that directs the gas flow received from the intake toward the field of view and the test specimen to produce uniform gas characteristics, thereby reducing imaging noise in the photosensor. The fan(s) may further include a secondary exhaust, which directs the gas flow toward the field of view further away than the main exhaust, improving the gas flow across another portion of the field of view that may not receive as much gas flow from the fan's intake and / or main exhaust.

[0018] In some of the disclosed examples, the imaging device further includes a manifold that further controls the gas flow within the field of view of the light sensor. This manifold can include a gas inlet that draws (suctions, guides) the gas passing through the field of view of the light sensor, and a gas outlet corresponding to the gas inlet of the fan.

[0019] As used herein, a material testing system that includes a material testing system that applies tension, compression, and / or torsional forces includes one or more components that induce displacement and / or load provided to apply and / or measure stress to a test sample. In some examples, a video extensometer system is used for sample strain testing. This test can include one or more of collecting high-resolution images, providing these images to an image processor, analyzing the images to identify one or more sample characteristics corresponding to displacement values or strain values, and generating an output corresponding to these characteristics. In some examples, the characteristics (such as width) identified from one or more of the collected images are compared to one or more sources such as a list of thresholds or images collected previously (i.e., prior to the test). In some examples, the values of the identified characteristics can be applied to one or more algorithms to generate an output corresponding to the displacement value or strain value associated with the test sample.

[0020] In an exemplary embodiment, the extensometer can include an external machine vision imaging device connected to a processing system or computing platform and / or video processing hardware, and can use software and / or hardware to convert data from the camera into an electrical signal, or can have a software interface adapted to the material testing system.

[0021] As disclosed herein, a camera-based image capture (e.g., vision or video) system is implemented in a materials testing system for measuring distortion in a test sample. Such a system collects multiple images of the test sample (i.e., collects during the test process). These images are synchronized with other signals (such as sample load, displacement of mechanical actuator and / or crosshead, etc.) that are relevant to the test. The images of the sample are analyzed by an algorithm (e.g., in real-time and / or after the test), and the location of specific sample characteristics during the test is identified and tracked. For example, by changes in the location, size, shape, etc. of such characteristics, it becomes possible to calculate the deformation of the test sample, and further, to analyze and calculate the sample distortion.

[0022] According to an aspect of the present disclosure, an exemplary video extensometer includes an optical sensor having a field of view and a fan positioned adjacent to the optical sensor within a housing and configured to mix gases within the field of view of the optical sensor. The housing has an air inlet that is directed toward the field of view of the optical sensor and draws in gases from a region within the field of view of the optical sensor adjacent to the optical sensor, and the housing has an air outlet configured to direct the gases blown out by the fan into the field of view of the optical sensor to mix the gases within the field of view of the optical sensor.

[0023] In some exemplary video extensometers, the housing includes a secondary exhaust port oriented toward a field of view adjacent to the photosensor and configured to direct at least a portion of the gas blown out by the fan toward a portion of the field of view adjacent to the photosensor. Some exemplary video extensometers further include a second fan positioned adjacent to the photosensor within a second housing and configured to mix the gas in the field of view of the photosensor, the second housing having a second intake port oriented toward a region in the field of view of the photosensor adjacent to the photosensor and drawing gas from the region in the field of view of the photosensor, and the housing having a second exhaust port configured to direct the gas blown by the second fan to mix the gas in the field of view. In some exemplary video extensometers, the first and second fans are positioned on either side of the photosensor.

[0024] In some exemplary video extensometers, in the installed configuration, the fan is positioned above the light sensor and the second fan is positioned below the light sensor. In some exemplary video extensometers, the second housing includes a secondary exhaust port that is oriented toward a field of view adjacent to the light sensor and is configured to direct at least a portion of the gas blown by the second fan toward a portion of the field of view adjacent to the light sensor.

[0025] In some exemplary video extensometers, the fan is configured to uniformly mix the gas occupying the area within the field of view of the light sensor between the light sensor and the test specimen. In some exemplary video extensometers, the fan is positioned at least partially toward the test specimen relative to the light sensor. In some exemplary video extensometers, the gas is air. In some exemplary video extensometers, the intake and exhaust ports are each at least as wide as the width of the test specimen.

[0026] In some exemplary video extensometers, the center of the intake port is positioned closer to the rear end of the housing than to the front end, and the front end of the housing is closer to the test specimen than to the rear end of the housing. In some exemplary video extensometers, the intake port is positioned to guide at least a portion of the gas onto the lens of the photosensor before the gas enters the housing. In some exemplary video extensometers, a fan is positioned to mix the gas over the entire length of the field of view between the photosensor and the test specimen. In some exemplary video extensometers, a manifold is further configured to direct the gas into the intake port of the fan, and at least a portion of the field of view extends through the manifold.

[0027] Next, refer to the figure. Figure 1 shows an exemplary extensometer system 10 for measuring changes in one or more properties of a test specimen 16 undergoing mechanical property testing. This exemplary extensometer system 10 can be connected, for example, to a test system 33 capable of mechanically testing the test specimen 16. The extensometer system 10 can measure and / or calculate changes in the test specimen 16 undergoing, for example, a compressive strength test, a tensile strength test, a shear strength test, a bending strength test, a deflection strength test, a tear strength test, a peel strength test (e.g., the strength of an adhesive bond), a torsional strength test, and / or any other arbitrary compression and / or tensile test. In addition or alternatively, the extensometer system 10 can perform dynamic testing.

[0028] According to the disclosed examples, the extensometer system 10 may include a test system 33 for manipulating and testing a test specimen 16, and / or a computing device 32 that is communication-coupled to the test system 33, a light source, and / or an imaging device, as further shown in Figure 8. The test system 33 applies a load to the test specimen 16 and measures the mechanical properties of the test, such as the displacement of the test specimen 16 and / or the force applied to the test specimen 16.

[0029] The extensometer system 10 includes a remote and / or integrated light source 14 (e.g., an LED array) and / or a reflective backscreen 18 for illuminating the test specimen 16. The extensometer system 10 also includes a computing device 32 (see also Figure 8) and a camera or imaging device 12. In some examples, the light source 14 and the imaging device 12 are configured to transmit and receive in infrared (IR) wavelengths, but other wavelengths are equally applicable. In some examples, one or both of the light source 14 or the 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 and used to identify one or more characteristics of the test specimen 16 and one or more markers 20 (including marker patterns).

[0030] 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 to have properties that enhance reflection and / or guide reflected light toward the imaging device. These properties may include the shape of the back screen 18 (e.g., a parabolic configuration) and / or measures to enhance reflection (e.g., application of corner cube reflectors, reflective materials, etc.). In addition or instead, a filter 30 may be placed on and / or applied to a surface that increases the amount of reflection and / or guides reflected light toward a desired direction and / or guides reflected light of a desired wavelength. In some examples, the filter 30 is configured as a collimating filter to direct as much reflected light as possible toward the imaging device 12 and away from other nearby components.

[0031] In the disclosed example, the computing device 32 can be used to configure the test system 33, control the test system 33, and / or process, display, report, and / or receive measurement data (e.g., transducer measurements such as force and displacement) and / or test results (e.g., peak force, break displacement) from the test system 33 for any other desired purpose. The extensometer system 10 connects to the test system 33 and software using a standard interface including Ethernet, analog encoder, or SPI. This allows the device to be plugged into an existing system and used by the existing system without requiring dedicated integrated software or hardware. The extensometer system 10 provides the test system 33 with axial and lateral encoder or analog information in real time. The illustrated extensometer system 10 and material testing machine 190 exchange real-time test data, including extension / strain data, with a computing device 32 which can be configured via a wired communication channel and / or wireless communication channel. The extensometer system 10 provides measurement and / or calculation of tensile / strain data captured from the test specimen 16 being tested in the test system 33, and further provides stress data and tensile / strain data to the computing device 32.

[0032] As disclosed herein, captured images are input from the imaging device to the computing device 32. The processor uses one or more algorithms and / or lookup tables to calculate the stretch / strain values ​​of multiple axes of the test specimen 16 (i.e., the change or percentage change in inter-target distance calculated by image monitoring of markers 20 attached to the test specimen 16). After calculation, this 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).

[0033] Figure 2 shows an example test specimen 16 measured in the extensometer system 10 of Figure 1. For example, one or more markings are attached to a surface 28 facing the light source 14 and the imaging device 12. The gripping portion 26 is configured to be positioned within the grip of the test system 33 (see also Figure 8) and applies force to the test specimen 16. For example, a cross-member loader applies force to the test specimen 16 while the grip is holding the test specimen 16 or otherwise coupled to the test system 33. A force applicator, such as a motor, moves the crosshead relative to the frame and applies force to the test specimen 16 as indicated by the bidirectional arrow 34. The force 34 pulling the gripping portions 26 apart can stretch the test specimen 16, and as a result, the markings move from a first position 20A to a second position 20B. In addition, or instead, the markings may change shape or size, and this change can also be measured by the computing device 32 by viewing the captured image. The force 34 can also move the edge of the test specimen from the first position 22A to the second position 22B. For example, in the first position, i.e., the initial position, the edge has a width 24A, and when the force 34 is applied, it decreases to a width 24B.

[0034] Based on the captured image, the computing device 32 is configured to perform stretching / strain in the measurement process. For example, to detect stretching / strain in the test specimen 16, the computing device 32 monitors the image provided via the imaging device 12. Once the computing device 32 identifies a change in the relative position between two or more of the markers and / or edges of the test specimen 16 (compared to their initial location at the start of the crosshead movement, for example), the computing device 32 measures the amount of change to calculate the amount of stretching and / or strain in the test specimen 16. As disclosed herein, the markers are configured to reflect light from a light source to the camera, while the back screen reflects light to generate a dark silhouette for edge analysis. In some examples, the extensometer system 10 is configured to perform optical width measurement of an opaque test specimen 16.

[0035] Figure 3 is a perspective view of an exemplary imaging device 300 that can be used to implement the imaging device 12 of Figure 1. Figure 4 is a side view of the exemplary imaging device 300 of Figure 3. As will be described in more detail below, the exemplary imaging device 300 includes a fan 302 to reduce imaging noise caused by turbulence in the field of view of the imaging device 300.

[0036] The imaging device 300 in Figure 3 includes two fans 302a and 302b, a photosensor 304, and a sensor housing 306. In addition to the photosensor 304, the sensor housing 306 houses image processing circuits, power supply circuits, and / or other components that perform imaging using the photosensor 304. The sensor housing 306 can further mount the imaging device 300 to a support structure for positioning the photosensor 304 relative to the test specimen 16.

[0037] The optical sensor 304 has a field of view 308. In the case of material testing, the optical sensor 304 is positioned such that the test sample 16 is located within the field of view 308 of the optical sensor 304. The volume between the optical sensor 304 and the test sample 16 is usually filled with a gas such as ambient air (e.g., air). Turbulence in the gas within the field of view can introduce noise into the image captured using the optical sensor 304, for example, due to differences in refractive index caused by changes in temperature, humidity, and / or density. This imaging noise can reduce the accuracy of the measurement.

[0038] To improve the uniformity of the gas within the field of view, the exemplary imaging device 300 includes fans 302a, 302b that generate a substantially uniform and / or consistent flow of gas (e.g., air) within the field of view 308 of the photosensor 304. The exemplary fans 302a, 302b are positioned within their respective fan housings 310a, 310b, which are mounted on the sensor housing 306. Figure 5 is a partially exploded view of the exemplary imaging device 300 of Figure 3. As shown in Figure 5, the fans 302a, 302b are positioned within the fan housings 310a, 310b to generate their respective gas flows through the fan housings 310a, 310b. In the examples of Figures 3 to 5, the fans 302a, 302b are positioned on both sides of the photosensor 304, for example, above and below the photosensor 304 in the installed orientation.

[0039] Each fan housing 310a and 310b includes an exhaust port 312 that directs the gas blown by their respective fans 302a and 302b toward the field of view 308 of the photosensor 304. Figures 6A and 6B are perspective views of the illustrative fan housings 310a and 310b shown in Figures 3 to 5. The fan housings 310a and 310b in Figure 3 can have the same structure, with fan housing 310a being positioned upside down relative to fan housing 310b such that the intake port of fan housings 310a and 310b is closer to the photosensor 304, and the outer intake port 316 is further away from the photosensor 304. In addition, each of the fan housings 310a, 310b and the exhaust port 312 can be positioned to align at least partially with the field of view 308.

[0040] In the examples shown in Figures 3 to 6B, the fan housings 310a, 310b may include one or more secondary exhaust ports 326 configured to direct the gas blown by the fans 302a, 302b toward a portion of the field of view 308 adjacent to the photosensor 304. The secondary exhaust ports (one or more) 326 can direct the gas partially toward the photosensor 304 and / or partially toward the test specimen.

[0041] Each of the fan housings 310a and 310b further includes an intake port 314 directed toward the field of view 308. Fans 302a and 302b receive gas through the intake port 314 and expel this gas through the exhaust port 312. In the examples of Figures 3 and 4, fans 302a and 302b are positioned adjacent to the light sensor 304. In some examples, fans 302a and 302b being adjacent to the light sensor 304 involves positioning the fans 302a and 302b as close as is practically achievable without obstructing the field of view 308. In addition or alternatively, fans 302a and 302b are positioned adjacent to the light sensor 304 by being positioned close enough to the light sensor 304 so that gas entering the intake port 314 can sweep across the lens of the light sensor 304 and / or so that gas can be drawn into the intake port 314, thereby causing gas to move across the lens of the light sensor 304. For example, the intake port 314 (e.g., the center of the intake port 314) is positioned closer to the rear end of the fan housings 310a and 310b than to the front end of the fan housings 310a and 310b (the front end of the fan housings 310a and 310b is closer to the test sample 16 than the rear end of the fan housings 310a and 310b). By positioning the intake port 314 to receive gas from the volume surrounding the photosensor 304, the exemplary fans 302a and 302b improve gas uniformity over a larger portion of the field of view 308 and further reduce imaging noise. In addition, the sweeping of the lens of the photosensor 304 by the gas improves the cooling of the photosensor 304.

[0042] The exemplary gas exhaust port 312 and the exemplary gas intake port 314 have a width that is at least the width of the field of view 308 of the optical sensor 304. However, in other examples, the widths of the gas exhaust port 312 and / or gas intake port 314 may be configured to obtain desired gas flow characteristics.

[0043] The illustrative fan housings 310a, 310b include an additional external intake port 316 that can draw gas into the fans 302a, 302b. In some examples, the intake port 314 and the external intake port 316 are configured to ensure that the airflow received through the intake port 314 is sufficient to mix the gas in the volume closest to the optical sensor 304.

[0044] To control the gas flow near the light sensor 304, the exemplary imaging device 300 may further include a manifold 318 positioned between the fans 302a, 302b. Figure 7A is an upper left front perspective view of the exemplary manifold 318 in Figure 3. Figure 7B is a lower right rear perspective view of the exemplary manifold 318 in Figure 3. The manifold 318 is omitted from Figures 4 and 5 to improve the visibility of the fan housings 310a, 310b. The exemplary manifold 318 includes gas intake openings 320a, 320b, an observation opening 322, and gas exhaust openings 324a, 324b. The gas intake openings 320a, 320b allow gas to enter the manifold 318. The observation opening 322 prevents the manifold 318 from obstructing or blocking the field of view 308. The observation opening 322 may also allow gas to enter the manifold 318, thereby further improving gas mixing in front of the photosensor 304 and / or facilitating the cooling of the photosensor 304.

[0045] The gas exhaust ports 324a and 324b allow gas to flow from the manifold 318 and are aligned with the intake ports 314 of the fans 302a and 302b. The positioning of the gas intake openings 320a and 320b and the gas exhaust ports 324a and 324b can be configured to facilitate the uniform movement and / or mixing of gas within the manifold 318, thereby improving the uniformity of gas within the field of view 308 and reducing imaging noise. In addition or alternatively, the positioning of the gas intake openings 320a and 320b and the gas exhaust ports 324a and 324b can also be configured to facilitate the sweeping of the lens of the photosensor 304 by the gas moving through the manifold 318.

[0046] The illustrated fan housings 310a and 310b are attached to the sensor housing 306 by fasteners and / or brackets. Fans 302a and 302b may be attached to the sensor housing 306, or they may be attached to the fan housings 310a and 310b which are attached to the sensor housing 306.

[0047] The examples in Figures 3 to 5 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.

[0048] Figure 8 is a block diagram of an extensometer system 10 illustrating an example in Figure 1. As shown in Figure 1, the extensometer system 10 includes a test system 33 and a computing device 32. The illustrative computing device 32 can be a general-purpose computer, a laptop computer, a tablet computer, a mobile device, a server, an all-in-one computer, and / or any other type of computing device. The computing device 32 in Figure 8 comprises a processor 802, which can be a general-purpose central processing unit (CPU). In some examples, the processor 802 can include one or more dedicated processing units such as an FPGA, a RISC processor with an ARM core, an image processing unit, a digital signal processor, and / or a system on a chip (SoC). The processor 802 executes machine-readable instructions 804 that can be stored locally in the processor (e.g., in an internal 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. The illustrated mass storage device 810 can be a hard drive, a solid-state storage drive, a hybrid drive, a RAID array, and / or any other mass data storage device. Bus 812 enables communication between processor 802, RAM 806, ROM 808, mass storage device 810, network interface 814, and / or input / output interface 816.

[0049] An example network interface 814 includes hardware, firmware, and / or software that connects the computing device 32 to a communication network 818, such as the Internet. For example, the network interface 814 may include IEEE 802.X compliant wireless and / or wired communication hardware for transmitting and / or receiving communications.

[0050] The example I / O interface 816 in Figure 8 includes hardware, firmware, and / or software that connects one or more input / output devices 820 to the processor 802 to provide input to the processor 802 and / or output from the processor 802. For example, the I / O interface 816 may include an image processing device for interface connection with a display device, a universal serial bus port for interface connection with one or more USB-compliant devices, FireWire®, a fieldbus, and / or any other type of interface. The example extensometer system 10 includes a display device 824 (e.g., an LCD screen) coupled to the 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 drive, multitouch touchscreen, gesture recognition interface, magnetic media drive, and / or any other type of input and / or output device.

[0051] The computing device 32 can access the non-temporary machine-readable medium 822 via the I / O interface 816 and / or one or more I / O devices 820. Examples of the machine-readable medium 822 in Figure 8 include optical discs (e.g., Compact Discs (CDs), Digital Versatile / Video 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 installed machine-readable medium.

[0052] The extensometer system 10 further comprises a test system 33 coupled to a computing device 32. In the example in Figure 8, the test system 33 is coupled to the computing device via an I / O interface 816 such as a USB port, Thunderbolt port, FireWire® (IEEE 1394) port, and / or any other type of serial or parallel data port. In some examples, the test system 33 is coupled to a network interface 814 and / or I / O interface 816 via a wired or wireless connection (e.g., Ethernet, Wi-Fi, etc.) directly or via a network 818.

[0053] The test system 33 comprises a frame 828, a load cell 830, a displacement transducer 832, a crossmember loader 834, a material fastener 836, and a control processor 838. The frame 828 provides rigid structural support for other components of the test system 33 that perform the test. The load cell 830 measures the force applied to the material under test by the crossmember loader 834 via the grip 836. The crossmember loader 834 applies force to the material under test, while the material fastener 836 (also referred to as the grip) grips the material under test or otherwise connects the material under test to the crossmember loader 834. The exemplary crossmember loader 834 comprises a motor 842 (or other actuator) and a crosshead 844. As used herein, “crosshead” refers to a component of the material test system that applies directional (axial) force and / or rotational force to a specimen. The material testing system may have one or more crossheads, and the crosshead(s) may be positioned in any suitable location and / or orientation within the material testing system. The crosshead 844 connects the material fixture 836 to the frame 828, and the motor 842 moves the crosshead relative to the frame to position the material fixture 836 and / or apply force to the material under test. Exemplary actuators that can be used to provide force and / or motion to the components of the extensometer system 10 include electric motors, pneumatic actuators, hydraulic actuators, piezoelectric actuators, relays, and / or switches.

[0054] The example test system 33 uses a motor 842 such as a servo motor or a direct-drive linear motor, but other systems may use different types of actuators. For example, hydraulic actuators, pneumatic actuators, and / or any other type of actuator may be used depending on the requirements of the system.

[0055] The illustrative grip 836 includes a compression platen, jaws, or other types of fasteners, depending on the mechanical properties being tested and / or the material under test. The grip 836 can be manually configured, controlled via manual input, and / or automatically controlled by a control processor 838. The crosshead 844 and grip 836 are components accessible to the operator.

[0056] The extensometer system 10 may further comprise one or more control panels 850, each having one or more mode switches 852. The mode switches 852 may include buttons, switches, and / or other input devices located on the operator control panel. For example, the mode switch 852 may include a button that controls a motor 842 to jog (e.g., position) the crosshead 844 to a specific position on the frame 828, a switch (e.g., a foot switch) that controls a grip actuator 846 to open and close a pneumatic grip 848, and / or any other input device that controls the operation of the test system 33.

[0057] The exemplary control processor 838 communicates with the computing device 32, for example, to receive test parameters from the computing device 32 and / or to report measurements and / or other results to the computing device 32. For example, the control processor 838 may include one or more communication interfaces or I / O interfaces that enable communication with the computing device 32. The control processor 838 can control the crossmember loader 834 to increase or decrease the applied force, control the fixture(s) 836 to grip or release the material under test, and / or receive measurements from the displacement transducer 832, load cell 830 and / or other transducers.

[0058] The exemplary control processor 838 is configured to perform the stretch / strain measurement process while the test specimen 16 is being tested in the test system 33. For example, to detect stretch / strain in the test specimen 16, the control processor 838 monitors images provided via the imaging device 12. Once the control processor 838 identifies a change in the location and / or position of the edge 22 of the test specimen 16 (e.g., compared to its initial location at the start of the movement of the crosshead 844), the control processor 838 measures the amount of change to calculate the amount of stretch and / or strain in the test specimen 16. For example, real-time video provided by the imaging device 12 captures the absolute position of the edge 22 and monitors their relative movement across several images to calculate stretch / strain in real time. Stress and strain data are exchanged between the extensometer system 10, the test system 33, and the computing device 32, typically compiled, and displayed via the display device 824.

[0059] The method and system can be implemented in hardware, software, and / or a combination of hardware and software. The method and / or system can be implemented centrally in at least one computing system, or distributedly, with different elements distributed across several interconnected computing systems. Any type of computing system or other device adapted to perform the method described herein is suitable. A typical combination of hardware and software may include a general-purpose computing system, along with a program or other code that, when loaded and executed, controls the computing system to perform the method described herein. Another typical embodiment may include an application-specific integrated circuit or chip. Some embodiments may include a non-temporary machine-readable (e.g., computer-readable) medium (e.g., flash drive, optical disk, magnetic storage disk, etc.) that stores one or more lines of machine-executable code, thereby causing a machine to perform a process such as that described herein. As used herein, the term “non-temporary machine-readable medium” includes all types of machine-readable storage media and is defined to exclude propagated signals.

[0060] As used herein, the terms “circuit” and “circuits” mean physical electronic components (i.e., hardware) and any software and / or firmware ("code") that can constitute the hardware, that the hardware can execute, and / or that can otherwise be associated with the hardware. As used herein, for example, a particular processor and memory may include a first “circuit” when executing one or more first lines of code, and a second “circuit” when executing one or more second lines of code. As used herein, “and / or” means any one or more items in the list linked by “and / or”. For example, “x and / or y” means any element in the set of three elements {(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” means any element of 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 to serve as an unrestricted example, case, or illustration. As used herein, the term “for example” begins a list of one or more unrestricted examples, cases, or illustrations. As used herein, whenever circuits include the hardware and code (if any) necessary to perform a certain function, the circuits are “operable” to perform that function, regardless of whether the performance of that function is disabled or not (e.g., by user-configurable settings, factory trim, etc.).

[0061] While the Method and / or System has been described with reference to certain specific embodiments, those skilled in the art will understand that various modifications and substitutions can be made without departing from the scope of the Method and / or System. In addition, many modifications can be made without departing from the scope of the Disclosure to adapt the teachings of the Disclosure to specific circumstances or materials. For example, the systems, blocks and / or components of the disclosed examples can be combined, divided, rearranged, and / or otherwise modified. Therefore, the Method and / or System is not limited to the specific embodiments disclosed. Rather, the Method and / or System includes all embodiments that fall within the scope of the appended claims, either literally or under the doctrine of equivalents.

Claims

1. This is a video growth meter, A light sensor with a field of view, A fan positioned within a housing and adjacent to the light sensor, and configured to mix the gas within the field of view of the light sensor, wherein the housing has an intake port adjacent to the light sensor and directed toward the field of view of the light sensor to draw gas from the region within the field of view of the light sensor, and the housing has an exhaust port configured to direct the gas blown out by the fan toward the field of view of the light sensor to mix the gas within the field of view of the light sensor, A video elongation meter equipped with this feature.

2. The video extensometer according to claim 1, wherein the housing includes a secondary exhaust port oriented toward the field of view adjacent to the light sensor, the secondary exhaust port configured to direct at least a portion of the gas blown out by the fan toward the portion of the field of view adjacent to the light sensor.

3. A video extensometer according to claim 1, further comprising a second fan positioned 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, wherein the second housing has a second intake port directed toward the region within the field of view of the optical sensor adjacent to the optical sensor for drawing the gas from the region within the field of view of the optical sensor, and the housing has a second exhaust port configured to direct the gas blown out by the second fan for mixing the gas in the field of view.

4. The video extensometer according to claim 3, wherein the first fan and the second fan are positioned on both sides of the optical sensor.

5. The video extensometer according to claim 3, wherein, in the installed configuration, the fan is positioned above the light sensor and the second fan is positioned below the light sensor.

6. The video extensometer according to claim 3, wherein the second housing includes a secondary exhaust port oriented toward the field of view adjacent to the optical sensor, the secondary exhaust port configured to direct at least a portion of the gas blown out by the second fan toward the portion of the field of view adjacent to the optical sensor.

7. The video extensometer according to claim 1, wherein the fan is configured to uniformly mix the gas occupying the area within the field of view of the light sensor between the light sensor and the test sample.

8. The video extensometer according to claim 1, wherein the fan is positioned at least partially toward the test sample with respect to the optical sensor.

9. The video extensometer according to claim 1, wherein the gas is air.

10. The video extensometer according to claim 1, wherein the intake port and the exhaust port each have a width at least the same as the width of the test sample.

11. The video extensometer according to claim 1, wherein the center of the intake port is positioned closer to the rear end of the housing than to the front end of the housing, and the front end of the housing is closer to the test sample than to the rear end of the housing.

12. The video extensometer according to claim 1, wherein the intake port is positioned to guide at least a portion of the gas onto the lens of the optical sensor before the gas enters the housing.

13. The video extensometer according to claim 1, wherein the fan is positioned to mix the gas over the entire length of the field of view between the light sensor and the test sample.

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

Images