Display multiple images on single axes

my gui contains a push button to load an rgb image and an axes to display it and another axes to display r g and b planes separately. how can i display these planes at the same time on a single axes ??

Answer 1

[Image Analyst]

Try this demo:

% Read in a standard MATLAB color demo image.
folder = fullfile(matlabroot, '\toolbox\images\imdemos');
baseFileName = 'peppers.png';
fullFileName = fullfile(folder, baseFileName);
% 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);
% Extract the individual red, green, and blue color channels.
redChannel = rgbImage(:, :, 1);
greenChannel = rgbImage(:, :, 2);
blueChannel = rgbImage(:, :, 3);
[rows columns numberOfColorChannels] = size(rgbImage);
% Make black strips to space them apart
widthOfStrip = 20;
verticalStrip = zeros(rows, widthOfStrip, 'uint8');
horizontalStrip = zeros(widthOfStrip, 2*columns + widthOfStrip, 'uint8');
% Make into color so we can stitch.
horizontalStrip = cat(3, horizontalStrip, horizontalStrip, horizontalStrip);
verticalStrip = cat(3, verticalStrip, verticalStrip, verticalStrip);
% Stitch together
outputImage = [rgbImage, verticalStrip, redChannel; horizontalStrip; greenChannel, verticalStrip, blueChannel];
imshow(outputImage);

[Rao]

it works :-)

but i dont know if i can put some space between image there are so tightly stiched :-(

[Image Analyst]

I've edited the code at the end so that you can add black strips, with a width of your choosing, in between the images.

[Subhadeep Koley]

The code is giving the following error.

Error using horzcat
Dimensions of arrays being concatenated are not consistent.

Error in image_demo (line 31)
outputImage = [rgbImage, verticalStrip, redChannel; horizontalStrip; greenChannel,
verticalStrip, blueChannel];

[Walter Roberson]

z = 0 * rgbImage;  %same size and type but all 0
redChannel = z;
redChannel(:,:,1) = rgbImage(:, :, 1);
greenChannel = z;
greenChannel(:,:,2) = rgbImage(:, :, 2);
blueChannel = z;
blueChannel(:,:,3) = rgbImage(:, :, 3);

Answer 2

[Walter Roberson]

If you use image() [or imagesc()] to display an image, you can specify the data coordinates to associate with the center of the lower-left pixel and the center of the upper-right pixel.

[Rao]

I=imread('peppers.ppm');

axes(handles.axes1)

imshow(I);

axes(handles.axes2);

imshow(uint8(I(:,:,1)));

imshow(uint8(I(:,:,2)));

imshow(uint8(I(:,:,3)));

this is the callback for push button can you please write code to display the the r g and b planes in axes2

[Walter Roberson]

Sorry, imshow() does not document the positioning meaning of its XData and YData parameters, so even if I had access to MATLAB to test now, it might change in any release.

I recommend that you instead use a routine whose positioning meanings are documented, image(). See the XData and YData property descriptions at http://www.mathworks.com/help/techdoc/ref/image_props.html