EDGE DETECTION-APPLICATION OF (FIRST AND SECOND) ORDER DERIVATIVE IN IMAGE PROCESSING

Communication

Abstract

Edge detection is one of the most frequently used techniques in digital image processing. Edges typically occur on the boundary between two different regions in an image. In this paper the first method we will find the edge for image by using (1st Order Derivative Filter ) method. In this method we take the 1st derivative of the intensity value across the image and find points where the derivative is maximum then the edge could be located. The gradient is a vector, whose components measure how rapid pixel value are changing with distance in the x and y direction. In second method we use the (2nd Order Derivative Operators) .
The 2nd derivative of an image where the image highlights regions of rapid intensity change and is therefore often used for edge detection zero crossing edge detectors. The zero crossing detector looks for places in the Laplacian of an image where the value of the Laplacian passes through zero i.e. points where the Laplacian changes sign. The criteria that used to comparison of results is (Root mean square error ) for different threshold values that explain the result obtain by 2nd order are best of the result obtain by 1st order for all values of threshold.