CV_Canny Finds edges in image using Canny algorithm edges = CV_Canny(srcimg,threhold1,threshold2,aperture_size,L2gradient) srcimg : single-channel 8-bit input image. threshold1 : first threshold for the hysteresis procedure. threshold2 : second threshold for the hysteresis procedure. aperture_size : aperture size for the Sobel() operator. L2gradient : a flag, indicating whether a more accurate This function can be used for finding edes in single channel 8 bit image. 'aperture_size' and 'L2gradient' are optionals. By default, aperture_size is 3 and L2gradient is false. For L2gradient: L_2 norm =sqrt{(dI/dx)^2 + (dI/dy)^2} should be used to calculate the image gradient magnitude (L2gradient=1 ), or whether the default L_1 norm =|dI/dx|+|dI/dy| is enough (L2gradient=0). This is curretly dummy function. It provides no functionality but is required for providing support for generating C code for OpenCV CV_CvtColor Siddhesh Wani