corner-detection

I have to find corners of shapes in an image. i have used Harris corner detection algorithm to find corner, but it is giving total corners present in an image and for finding corners for a particular shape in that image it is not feasible. please suggest some other approach. You could use Harris corner detection algorithm. Corners are junction of two edges, where an edge is a sudden change in image brightness. This algorithm takes the differential of the corner score into account with reference to direction directly (wikipedia). Function cornerSubPix() refines the corner location - it iterates

I am implementing a Harris corner detector for educational purposes but I'm stuck at the harris response part. Basically, what I am doing, is: Compute image intensity gradients in x- and y-direction Blur output of (1) Compute Harris response over output of (2) Suppress non-maximas in output of (3) in a 3x3-neighborhood and threshold output 1 and 2 seem to work fine; however, I get very small values as the Harris response, and no point does reach the threshold. Input is a standard outdoor photography. [...] [Ix, Iy] = intensityGradients(img); g = fspecial('gaussian'); Ix = imfilter(Ix, g); Iy =

BW = poly2mask(x, y, m, n) computes a binary region of interest (ROI) mask, BW, from an ROI polygon, represented by the vectors x and y. The size of BW is m-by-n. poly2mask sets pixels in BW that are inside the polygon (X,Y) to 1 and sets pixels outside the polygon to 0. Problem: Given such a binary mask BW of a convex quadrilateral, what would be the most efficient way to determine the four corners? E.g., Best Solution so far: Use edge to find the bounding lines, the Hough transform to find the 4 lines in the edge image and then find the intersection points of those 4 lines or use a corner