Visualizing image contours
A curve that joins all the points that lie continuously along the boundary that have the same value as the color of the pixels is known as a contour. Contours are used for detecting the boundaries in an image. Contours are also used for image segmentation. Contours are usually computed using edges in an image. However, contours are closed curves and that is their main distinction from the edges in an image. It is always a good idea to apply the thresholding operation to an image before we extract contours from an image. It will increase the accuracy of the computation of the contour operation.
The cv2.findContours() function is used to compute the contours in an image. This function accepts an image array, the mode of the retrieval of the contours, and the method for the approximation of contours as arguments. It then returns a list of computer contours in the image. The contour retrieval mode can be any of the following:
CV_RETR_CCOMPCV_RETR_TREE...