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Canny thresholding issues

Hi, I have some unclarities about thresholding in Canny's algorithm. Let's take this: image description

This is an image with max and min luminance of 255 and 0 respectively, and the type is set to be CV_8U. I have added a trackbar to adjust threshold levels on the fly. The results are:

for aperture size of 3, the edge is being detected only up to ~780 for both thresholds. I thought it could be because of the gaussian blur, but I have some doubts, 'cause pre-adding gaussian blur to the image doesn't change the 780 value at all. I would expect the edge to be found till 1020, as the gradient is equal only to the horizontal part.
for aperture size of 5, the edge is being detected up to... ~7800.

I have no idea what's going on. same is for aperture 7. this is weird. could you please help me?

Canny thresholding issues

Hi, I have some unclarities about thresholding in Canny's algorithm. Let's take ~~this:~~ this:

image description

This is an image with max and min luminance of 255 and 0 respectively, and the type is set to be CV_8U. I have added a trackbar to adjust threshold levels on the fly. The results are:

for aperture size of 3, the edge is being detected only up to ~780 for both thresholds. I thought it could be because of the gaussian blur, but I have some doubts, 'cause pre-adding gaussian blur to the image doesn't change the 780 value at all. I would expect the edge to be found till 1020, as the gradient is equal only to the horizontal part.
for aperture size of 5, the edge is being detected up to... ~7800.

I have no idea what's going on. same is for aperture 7. this is weird. could you please help me?

Canny thresholding issues

Hi, I have some unclarities about thresholding in Canny's algorithm. Let's take this:

image description

This is an image with max and min luminance of 255 and 0 respectively, and the type is set to be CV_8U. I have added a trackbar to adjust threshold levels on the fly. The results are:

for aperture size of 3, the edge is being detected only up to ~780 for both thresholds. I thought it could be because of the gaussian blur, but now I have some doubts, ~~'cause~~ as pre-adding gaussian blur to the image doesn't ~~change~~ lower the 780 value at all. I would expect the edge to be found till 1020, as the gradient is equal only to the horizontal part.
for aperture size of 5, the edge is being detected up to... ~7800.

I have no idea what's going ~~on. same is for aperture 7. this is weird.~~ on, could you please help me?