Standard examples of Convolution Masks
Image filtering allows you to apply various effects on photos. The type of image filtering described here uses a 2D filter similar to the one included in Paint Shop Pro as User Defined Filter and in Photoshop as Custom Filter. Here are some standard convolution masks.
Example
im = imread('Image1.jpg'); % original image % Low Pass Filter lowPassfilterMask = [1 1 1; 1 1 1; 1 1 1]/9; lowPassfilterMaskImage = imfilter(im,lowPassfilterMask); % High Pass Filter HighPassfilterMask = [0 -1 0; -1 5 -1; 0 -1 0]; HighPassfilterMaskImage = imfilter(im,HighPassfilterMask); % Horizontal Edge Detection HorizontalEdgeDetectionMask = [1 1 1; 0 0 0; -1 -1 -1]; HorizontalEdgeDetectionMaskImage = imfilter(im,HorizontalEdgeDetectionMask); %plotting images subplot(2,2,1); imshow(im); title('original image'); subplot(2,2,2); imshow(lowPassfilterMaskImage); title('Low pass filter'); subplot(2,2,3); imshow(HighPassfilterMaskImage); title('High pass filter Image'); subplot(2,2,4); imshow(HorizontalEdgeDetectionMaskImage); title('Horizontal edge detection');