Systems for width measurement corrections of test specimens based on background brightness data of captured images
The present disclosure describes systems and methods to correct for edge-position error associated with brightness levels of an associated back screen in a video extensometer system. In some examples, to correct for edge-position error, a processing system is configured to execute an edge detection algorithm to measure and/or calculate a difference between a perceived edge-position and a reference edge-position associated with an amount of error, and calculate a correction term to address the error. The correction term can be added to the result of the edge detection algorithm in case of white-to black transition, and subtracted in case of black-to-white transition to correct for the error.
1. A system for correcting a measurement of a test specimen, the system comprising:
an imaging device configured to capture at least one image of the test specimen; and
a processing system comprising a memory storing an edge detection algorithm and reference data, the processing system configured to:
receive the at least one image of the test specimen from the imaging device;
measure, in the at least one image, a perceived edge-position at one or more positions along an edge of the test specimen;
execute the edge detection algorithm to determine, based on background brightness data of the perceived edge-position, a difference between the perceived edge-position and a reference edge-position of the reference data;
calculate, using the difference, a correction term; and
generate corrected measurement data based on the correction term, wherein the corrected measurement data comprises a corrected width, and the generating of the corrected width comprises adding or subtracting the correction term to or from a measured width of the test specimen.
2. The system of claim 1 , wherein the generating of the measurement data by the processing system further comprises at least one of:
adding the correction term to the measured width based on a determination that the perceived edge-position comprises a white-to-black transition from a background screen to the test specimen; or
subtracting the correction term from the measured width based on a determination that the perceived edge-position comprises a black-to-white transition from the test specimen to the background screen.
3. The system of claim 1 , wherein the corrected data comprises a corrected edge-position.
4. The system of claim 1 , wherein the processing system receives the background brightness data from the imaging device.
5. The system of claim 1 , wherein the processing system measures the background brightness data using the at least one image.
6. The system of claim 1 , wherein the processing system is further configured to:
receive test specimen measurement data of the test specimen; and
generate, using the test specimen measurement data, the reference edge-position.
7. The system of claim 6 , wherein the test specimen measurement data comprises at least one of force data, displacement data, extension data, or strain data.
8. The system of claim 6 , further comprising a testing system configured to generate the test specimen measurement data and transmit the test specimen measurement data to the processing system.
9. The system of claim 6 , wherein the processing system is further configured to, using the at least one image, generate the test specimen measurement data.
10. The system of claim 1 , wherein the determination of the difference by the processing system is further based on direction of contrast data of the at least one image or level of contrast data of the at least one image.
11. The system of claim 1 , wherein the determination of the difference by the processing system is further based on focus data of the at least one image.
12. The system of claim 11 , wherein the processing system receives the focus data from the imaging device.
13. The system of claim 11 , wherein the processing system generates the focus data based on the at least one image.
14. The system of claim 1 , further comprising a background screen to provide illumination to silhouette the test specimen.
15. A processing system configured to:
receive at least one image of a test specimen from an imaging device;
measure, in the at least one image, a perceived edge-position at one or more positions along an edge of the test specimen;
execute an edge detection algorithm to determine, based on background brightness data of the perceived edge-position, a difference between the perceived edge-position and a reference edge-position of the reference data;
calculate, using the difference, a correction term; and
generate corrected measurement data based on the correction term,
wherein the corrected measurement data comprises a corrected width, and the generating of the corrected measurement data comprises at least one of:
adding the correction term to a measured width of the test specimen based on a determination that the perceived edge-position comprises a white-to-black transition from a background screen to the test specimen; or
subtracting the correction term from the measured width based on a determination that the perceived edge-position comprises a black-to-white transition from the test specimen to the background screen.
16. A system for correcting a measurement of a test specimen, the system comprising:
an imaging device configured to capture at least one image of the test specimen; and
a processing system comprising a memory storing an edge detection algorithm and reference data, the processing system configured to:
receive at least one image of the test specimen from the imaging device;
measure, in the at least one image, a perceived edge-position at one or more positions along an edge of the test specimen;
execute the edge detection algorithm to determine, based on focus data of the at least one image, a difference between the perceived edge-position and a reference edge-position of the reference data;
calculate, using the difference, a correction term;
generate corrected measurement data for the measurement of the perceived edge-position based on the correction term, wherein the corrected measurement data comprises a corrected width; and
the generating of the corrected measurement data by the processing system comprises at least one of:
adding the correction term to a measured width of the test specimen based on a determination that the perceived edge-position comprises a white-to-black transition from a background screen to the test specimen; or
subtracting the correction term from the measured width based on a determination that the perceived edge-position comprises a black-to-white transition from the test specimen to the background screen.
17. The system of claim 15 , wherein the processing system receives the background brightness data from the imaging device.
18. The system of claim 15 , wherein the processing system measures the background brightness data using the at least one image.
19. The system of claim 16 , wherein the processing system is further configured to receive test specimen measurement data of the test specimen; and generate, using the test specimen measurement data, the reference edge-position.
20. The system of claim 19 , wherein the test specimen measurement data comprises at least one of force data, displacement data, extension data, or strain data.