MATLAB: Problem with filtering an image

clownconvconvolutiondigital image processingfigurefilterfilteringgaussianimageimage processingImage Processing Toolboxpalhaco

Whats up folks I'm having a little problem in filtering this image: http://img15.imageshack.us/img15/9287/palhaco.png

The source code is bellow:

C = imread('Palhaco.png');
imshow(C);
figure;
g = fspecial('gaussian',15,2);
imagesc(g);  colormap(gray);
surfl(g)
figure;
gC = convn(C,g,'same');
imshow(convn(C,[-1 1],'same'));
figure;
imshow(convn(gC,[-1 1],'same'));
figure;
dx = convn(g,[-1 1],'same');
imshow(convn(C,dx,'same'));
figure;
lg = fspecial('log',15,2);
lC = convn(C,lg,'same');
imshow(lC)
figure
imshow(C + .2*lC)

When I compile the program, It returns: "Integers can only be combined with integers of the same class, or scalar doubles."

I'm open to any idea at all!

Best Answer

The code is very experimental so far. It seems like you're doing some experiments in trying to get rid of the pattern noise, but not doing a very good job of it (so far). Anyway, this will "fix" your code. It will at least run now without errors, and it does what you are telling it to do, even though that is kind of gibberish. As a bonus I put them all on one screen with titles above the images.

workspace;  % Make sure the workspace panel is showing.
fontSize = 15;
% Read in original color image.
folder = 'C:\Documents and Settings\myUserName\My Documents\Downloads';
baseFileName = 'Palhaco.png';
fullFileName = fullfile(folder, baseFileName);
rgbImage = imread(fullFileName);
subplot(3, 3, 1);
imshow(rgbImage);
title('Original Image', 'FontSize', fontSize);
% Enlarge figure to full screen.
set(gcf, 'units','normalized','outerposition',[0 0 1 1]);
% Get a convolution kernel.
g = fspecial('gaussian',15,2);
subplot(3, 3, 2);
imshow(g, []);
title('g - Gaussian Kernel', 'FontSize', fontSize);
subplot(3, 3, 3);
surfl(g)
title('g - Gaussian Kernel', 'FontSize', fontSize);
grayImage = rgbImage(:,:,2); % Get green channel.
gC = conv2(grayImage, g,'same');
subplot(3, 3, 4);
imshow(conv2(grayImage,[-1 1],'same'));
title('gC - Original Image Convolved with g', 'FontSize', fontSize);
subplot(3, 3, 5);
imshow(conv2(grayImage,[-1 1],'same'));
title('Original Image Convolved with [-1 1]', 'FontSize', fontSize);
subplot(3, 3, 6);
imshow(conv2(gC,[-1 1],'same'));
title('gC convolved with [-1 1]', 'FontSize', fontSize);
dx = conv2(g,[-1 1],'same');
subplot(3, 3, 7);
imshow(convn(grayImage, dx, 'same'));
title('dx', 'FontSize', fontSize);
lg = fspecial('log',15,2);
lC = conv2(grayImage, lg, 'same');
subplot(3, 3, 8);
imshow(lC)
title('lC', 'FontSize', fontSize);
subplot(3, 3, 9);
imshow(single(grayImage) + .2*lC);
title('single(grayImage) + .2*lC', 'FontSize', fontSize);

Related Solutions

MATLAB: Crop dark area and display the face only

Convert to grayscale and then threshold and find the bounding box

clc;    % Clear the command window.
close all;  % Close all figures (except those of imtool.)
imtool close all;  % Close all imtool figures.
clear;  % Erase all existing variables. Or clearvars if you want.
workspace;  % Make sure the workspace panel is showing.
format long g;
format compact;
fontSize = 20;
% Read in the color image.
folder = pwd;
baseFileName = 'm2.bmp';
% Get the full filename, with path prepended.
fullFileName = fullfile(folder, baseFileName);
if ~exist(fullFileName, 'file')
  % Didn't find it there.  Check the search path for it.
  fullFileName = baseFileName; % No path this time.
  if ~exist(fullFileName, 'file')
    % Still didn't find it.  Alert user.
    errorMessage = sprintf('Error: %s does not exist.', fullFileName);
    uiwait(warndlg(errorMessage));
    return;
  end
end
rgbImage = imread(fullFileName);
% Get the dimensions of the image.  numberOfColorBands should be = 3.
[rows, columns, numberOfColorBands] = size(rgbImage);
% Display the original color image.
subplot(2, 3, 1);
imshow(rgbImage, []);
axis on;
title('Original Color Image', 'FontSize', fontSize);
drawnow;
% Enlarge figure to full screen.
set(gcf, 'units','normalized','outerposition',[0 0 1 1]);
% Histogram the red channel, but there is a huge spike at 255 so let's not count those.
subplot(2, 3, 2);
grayImage = rgb2gray(rgbImage);
imshow(grayImage, []);
title('Gray Scale version', 'FontSize', fontSize);
subplot(2, 3, 3);
histogram(grayImage(grayImage<255))
grid on;
title('Histogram of Gray Scale Image', 'FontSize', fontSize);
someThresholdValue = 150;
binaryImage = grayImage > someThresholdValue;
% Take largest blob
binaryImage = bwareafilt(binaryImage, 1);
subplot(2, 3, 4);
imshow(binaryImage);
grid on;
title('Binary Image', 'FontSize', fontSize);
% Label the binary image.
labeledImage = bwlabel(binaryImage);
props = regionprops(labeledImage, 'BoundingBox');
bbox = props.BoundingBox
croppedImageRGB = imcrop(rgbImage, bbox);
subplot(2, 3, 5);
imshow(croppedImageRGB);
grid on;
title('Cropped RGB Image', 'FontSize', fontSize);
% Gray scale version of cropped image
croppedImageGray = imcrop(grayImage, bbox);
subplot(2, 3, 6);
imshow(croppedImageGray);
grid on;
title('Cropped Gray Scale Image', 'FontSize', fontSize);

MATLAB: Adding Noise to the Image

Try this:

clc;    % Clear the command window.
close all;  % Close all figures (except those of imtool.)
imtool close all;  % Close all imtool figures.
clear;  % Erase all existing variables.
workspace;  % Make sure the workspace panel is showing.
format longg;
format compact;
fontSize = 20;
%===============================================================================
% Read in a standard MATLAB gray scale demo image.
folder = fileparts(which('cameraman.tif')); % Determine where demo folder is (works with all versions).
baseFileName = 'cameraman.tif';
% Get the full filename, with path prepended.
fullFileName = fullfile(folder, baseFileName);
% Check if file exists.
if ~exist(fullFileName, 'file')
  % File doesn't exist -- didn't find it there.  Check the search path for it.
  fullFileNameOnSearchPath = baseFileName; % No path this time.
  if ~exist(fullFileNameOnSearchPath, 'file')
    % Still didn't find it.  Alert user.
    errorMessage = sprintf('Error: %s does not exist in the search path folders.', fullFileName);
    uiwait(warndlg(errorMessage));
    return;
  end
end
grayImage = imread(fullFileName);
% Get the dimensions of the image.  
% numberOfColorBands should be = 1.
[rows, columns, numberOfColorBands] = size(grayImage);
if numberOfColorBands > 1
  % It's not really gray scale like we expected - it's color.
  % Convert it to gray scale by taking only the green channel.
  grayImage = grayImage(:, :, 2); % Take green channel.
end
% Display the original gray scale image.
subplot(1, 2, 1);
imshow(grayImage, []);
title('Original Grayscale Image', 'FontSize', fontSize);
% Enlarge figure to full screen.
set(gcf, 'Units', 'Normalized', 'OuterPosition', [0 0 1 1]);
% Give a name to the title bar.
set(gcf, 'Name', 'Demo by ImageAnalyst', 'NumberTitle', 'Off') 
% Initialize an output image.
noisyImage = grayImage; % Initialize
% Get 5,000 random locations
noiseIndexes = randperm(numel(grayImage), 5000);
% Add noise
noisyImage(noiseIndexes) = 255;
% Display the noisy image.
subplot(1, 2, 2);
imshow(noisyImage, []);
title('Noisy Image', 'FontSize', fontSize);
axis on;

Best Answer

Related Solutions

MATLAB: Crop dark area and display the face only

MATLAB: Adding Noise to the Image

Related Question