I'm trying to filter an image with a mode filter just like medfilt2 but using the mode rather than the median. Does this exist?
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Nope, but you could use colfilt to do this really easily.
See my demo. Copy, paste, save as test.m, and run.
% Demo to take the local mode of a gray scale image. % userImage, if passed in, is used as the image. % If userImage is not passed in, user is asked to use a demo image. function test(userImage) % Clean up. clc; % Clear the command window. close all; % Close all figures (except those of imtool.) workspace; % Make sure the workspace panel is showing.
% Change the current folder to the folder of this m-file. % (The line of code below is from Brett Shoelson of The Mathworks.) % Don't use these lines if you're calling this from another m-file. if(~isdeployed) cd(fileparts(which(mfilename))); end
% Check that user has the Image Processing Toolbox installed. hasIPT = license('test', 'image_toolbox'); if ~hasIPT % User does not have the toolbox installed. message = sprintf('Sorry, but you do not seem to have the Image Processing Toolbox.\nDo you want to try to continue anyway?'); reply = questdlg(message, 'Toolbox missing', 'Yes', 'No', 'Yes'); if strcmpi(reply, 'No') % User said No, so exit. return; end end
% Initialize. fontSize = 20; if nargin == 0 % No image passed in on the command line. % Read in one of the standard MATLAB demo images % as our original gray scale image and display it. promptMessage = sprintf('Which image do you want to use.\nThe coins or the cameraman?'); button = questdlg(promptMessage, 'Select Image', 'Coins', 'Cameraman', 'Coins'); if strcmp(button, 'Coins') grayImage = double(imread('coins.png')); % Cast to double. else grayImage = double(imread('cameraman.tif')); % Cast to double. end else % Use the image array passed in on the command line. grayImage = double(userImage); % Cast to double. end
% Start timing. startTime = tic;
subplot(2, 2, 1); imshow(grayImage, ); title('Original Image', 'FontSize', fontSize); set(gcf, 'Position', get(0,'Screensize')); % Maximize figure.
% Perform a mode filter. % Output image is the mode of the input image in a 3 by 3 sliding window. ModeFilterFunction = @(x) mode(x(:)); modeImage = nlfilter(grayImage, [3 3], ModeFilterFunction); % An alternate way of doing the mode filter is on the next line: % modeImage = reshape(mode(im2col(originalImage,[3 3],'sliding')), size(originalImage)-2); subplot(2, 2, 2); imshow(modeImage, ) title('Mode Image', 'FontSize', fontSize);
elapsedTime = toc(startTime); message = sprintf('Done!\n\nElapsed time = %.2f seconds.', elapsedTime); msgbox(message); return; % End of local_mode() function.