opencv

How to verify the correctness of calibration of a webcam?

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Hmm, are you looking for “handsome” or “accurate”? Camera calibration is one of the very few subjects in computer vision where accuracy can be directly quantified in physical terms, and verified by a physical experiment. And the usual lesson is that (a) your numbers are just as good as the effort (and money) you put … Read more

Detect semicircle in OpenCV

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Use houghCircle directly on your image, don’t extract edges first. Then test for each detected circle, how much percentage is really present in the image: int main() { cv::Mat color = cv::imread(“../houghCircles.png”); cv::namedWindow(“input”); cv::imshow(“input”, color); cv::Mat canny; cv::Mat gray; /// Convert it to gray cv::cvtColor( color, gray, CV_BGR2GRAY ); // compute canny (don’t blur with … Read more