Abstract: A method of detecting optical defects in a transparency may comprise the steps of providing a digital image of the transparency having a plurality of image pixels and detecting at least one candidate defect. The candidate defect may be detected by determining a grayscale intensity of each one of the image pixels and calculating an intensity gradient across adjacent pairs of the image pixels. Each image pixel may be assigned a gradient value comprising a maximum of the absolute value of the intensity gradients associated with the image pixel. A gradient image may be constructed comprising the gradient values assigned to corresponding ones of the image pixels. Image pixels may be identified as candidate pixels if such image pixels have a gradient value exceeding a gradient threshold. The candidate pixels may comprise the optical defect.

Abstract: A method of detecting optical defects in a transparency may comprise the steps of providing a digital image of the transparency having a plurality of image pixels and detecting at least one candidate defect. The candidate defect may be detected by determining a grayscale intensity of each one of the image pixels and calculating an intensity gradient across adjacent pairs of the image pixels. Each image pixel may be assigned a gradient value comprising a maximum of the absolute value of the intensity gradients associated with the image pixel. A gradient image may be constructed comprising the gradient values assigned to corresponding ones of the image pixels. Image pixels may be identified as candidate pixels if such image pixels have a gradient value exceeding a gradient threshold. The candidate pixels may comprise the optical defect.

Abstract: A method of detecting optical defects in a transparency may comprise the steps of providing a digital image of the transparency having a plurality of image pixels and detecting at least one candidate defect. The candidate defect may be detected by determining a grayscale intensity of each one of the image pixels and calculating an intensity gradient across adjacent pairs of the image pixels. Each image pixel may be assigned a gradient value comprising a maximum of the absolute value of the intensity gradients associated with the image pixel. A gradient image may be constructed comprising the gradient values assigned to corresponding ones of the image pixels. Image pixels may be identified as candidate pixels if such image pixels have a gradient value exceeding a gradient threshold. The candidate pixels may comprise the optical defect.

Abstract: A system for evaluating optical distortion in an aircraft transparency, such as a windshield, is disclosed. The system utilizes high resolution digital images (a reference image and a test image) of a test grid structure having a pattern of visible index locations. In one embodiment, the test image is taken through the transparency under test, and the reference image is taken without the transparency. The two images are processed and analyzed by a computing device to determine displacement of each index location, relative to the reference image. The displacement data is further processed to obtain vector divergence field data that represents a quantitative measurement of the optical distortion. The optical distortion measurement data is then rendered in a suitable format that allows the transparency to be rated against certain quality criteria.

Abstract: A system for evaluating optical distortion in an aircraft transparency, such as a windshield, is disclosed. The system utilizes high resolution digital images (a reference image and a test image) of a test grid structure having a pattern of visible index locations. In one embodiment, the test image is taken through the transparency under test, and the reference image is taken without the transparency. The two images are processed and analyzed by a computing device to determine displacement of each index location, relative to the reference image. The displacement data is further processed to obtain vector divergence field data that represents a quantitative measurement of the optical distortion. The optical distortion measurement data is then rendered in a suitable format that allows the transparency to be rated against certain quality criteria.