如何在OpenCV中计算连续的非零像素之间的零像素？

Question

From a grayscale image I obtained its non-zero pixel coordinates using this line of code in OpenCV:

cv::Mat nonZeroCoordinates;
cv::findNonZero(image, nonZeroCoordinates);

Now, I want to count the zero pixels between two consecutive non-zero elements in image . But should I move through columns or rows first? For instance, if I have non-zero pixels at point (30, 20) and (30, 23) in a 40x40 mat, and moving through columns give me 2 zero pixels between them, and moving through rows gives me (39-30) + 40 + 40 + 29 = 118 pixels. Through which way should I count these pixels correctly? Is there any better way then just nested loop for this purpose? Thank you.

Answer 1

I think you should fit a line over the endpoints and count the zero pixels under it. OpenCV has a LineIterator class which you can make a 8-connected or 4-connected line from (30, 20) to (30, 23) and check the values.