Gray projecting integral method for line detection

A gray projecting integral(GPI) method was developed which improves the robustness and accuracy of line detection in images.The method projects the image to a plane in Cartesian coordinates with the gray values of pixels projected to the same point added to produce a GPI vector.The projecting direction is then rotated to compute various GPI vectors for a GPI matrix of the source image.The equation for the line in the image is then obtained from the row and column indexes of the extremums elements in the matrix.Experimental results show that the GPI method can quickly and accurately detect the line in the image without previous edge point detection,which avoids errors resulting from inproper thresholds in the edge point detection when using conventional methods.