MATLAB: I have following code of image extraxtion but i got gray scale image output while giving input color image ,how could i get the color image output

color outputcolor segmentationImage Processing Toolboxmasking

a=imread('new2.png');

c=zeros(35,57,3)

e=zeros(35,57,3)

for i=1:35; for j=1:57; if a(i,j,1)>233 if a(i,j,1)<254 c(i,j,1)=a(i,j,1);

    for i=1:35;
    for j=1:57;
        if a(i,j,2)>25
            if a(i,j,2)<30
                c(i,j,2)=a(i,j,2);
    for i=1:35;
    for j=1:57;
        if a(i,j,3)>35
            if a(i,j,3)<40
                c(i,j,3)=a(i,j,3);
            end
        end
    end
end
            end
        end
            end
            end
            end
            end
            end
            end

e=logical(c) colormap(jet) image(e)

Best Answer

I wouldn't do it that inefficient way at all. But that's another issue. Your problem is that you're casting your color image to a logical image, e, and then displaying that e instead of the color image c. Why are you doing that? Also, I apply a colormap after I've displayed the image, not before and I'm not sure if displaying an image will reinitialize the colormap.

I'd do it like this:

rgbImage=imread('new2.png');
% Display the original color image.
subplot(2, 3, 1);
imshow(rgbImage);
title('Original Color Image', 'FontSize', fontSize);
% Enlarge figure to full screen.
set(gcf, 'units','normalized','outerposition',[0 0 1 1]);
% Extract the individual red, green, and blue color channels.
redChannel = rgbImage(:, :, 1);
greenChannel = rgbImage(:, :, 2);
blueChannel = rgbImage(:, :, 3);
binaryImageR = redChannel > 233;
binaryImageG = redChannel > 25 & redChannel < 30;
binaryImageB = blueChannel > 35 & blueChannel < 40;
% Display the binary images.
subplot(2, 3, 2);
imshow(binaryImageR);
title('Red Binary Image', 'FontSize', fontSize);
subplot(2, 3, 3);
imshow(binaryImageG);
title('Green Binary Image', 'FontSize', fontSize);
subplot(2, 3, 4);
imshow(binaryImageB);
title('Red Binary Image', 'FontSize', fontSize);
% Combine
binaryImage = binaryImageR & binaryImageG & binaryImageB;
subplot(2, 3, 5);
imshow(binaryImage);
title('Overall Binary Image', 'FontSize', fontSize);
% Mask the image.
maskedRgbImage = bsxfun(@times, rgbImage, cast(binaryImage,class(rgbImage)));
subplot(2, 3, 6);
imshow(maskedRgbImage);
title('Masked Color Image', 'FontSize', fontSize);

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MATLAB: How to make backgound of image black

This script will do it. Adjust as needed.

clc;    % Clear the command window.
close all;  % Close all figures (except those of imtool.)
imtool close all;  % Close all imtool figures if you have the Image Processing Toolbox.
clear;  % Erase all existing variables. Or clearvars if you want.
workspace;  % Make sure the workspace panel is showing.
format long g;
format compact;
fontSize = 13;
% 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
% Read in a standard MATLAB color demo image.
folder = 'D:\Temporary stuff';
baseFileName = 'moogseed5.jpg';
% 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);
title('Original Color Image', 'FontSize', fontSize);
% Enlarge figure to full screen.

set(gcf, 'units','normalized','outerposition',[0 0 1 1]);
% Get the dimensions of the image.  
% numberOfColorBands should be = 3 for an RGB image.
[rows, columns, numberOfColorBands] = size(rgbImage);
if numberOfColorBands > 1
  % Convert it to gray scale by taking only the green channel.
  % The green channel will have the highest contrast for these green seeds.
  grayImage = rgbImage(:, :, 2); % Take green channel.
end
% Display the original green channel gray scale image.
subplot(2, 3, 2);
imshow(grayImage, []);
title('Green Channel 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') 
% Let's compute and display the histogram.
[pixelCount, grayLevels] = imhist(grayImage);
subplot(2, 3, 3); 
bar(grayLevels, pixelCount);
grid on;
title('Histogram of Green Channel', 'FontSize', fontSize);
xlim([0 grayLevels(end)]); % Scale x axis manually.
% Create a binary image via thresholding.
binaryImage = grayImage > 55;
% Display the image.


subplot(2, 3, 4);
imshow(binaryImage, []);
title('Binary Image', 'FontSize', fontSize);
% Clean up.
binaryImage = imclearborder(binaryImage);
binaryImage = imfill(binaryImage, 'holes');
binaryImage = bwareaopen(binaryImage, 500);
% Display the image.
subplot(2, 3, 5);
imshow(binaryImage, []);
title('Cleaned Binary Image', 'FontSize', fontSize);
% Mask the RGB image using bsxfun() function
maskedRgbImage = bsxfun(@times, rgbImage, cast(binaryImage, class(rgbImage)));
% Display the image.
subplot(2, 3, 6);
imshow(maskedRgbImage, []);
title('Masked RGB Image', 'FontSize', fontSize);

MATLAB: Change color in image

Why don't you have access to the original image? If you don't, for some strange reason, then you can find the pixels by first extracting the individual color planes, then median filtering them and replacing the colored pixels with the median filtered pixels. It will work a lot better if you have the original uncompressed image, rather than the blurry one you uploaded, which does not have sharp graphics.

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, 2, 1);
imshow(rgbImage);
axis on;
title('Original Color Image', 'FontSize', fontSize);
% Enlarge figure to full screen.
set(gcf, 'units','normalized','outerposition',[0 0 1 1]);
% Extract the individual red, green, and blue color channels.
redChannel = rgbImage(:, :, 1);
greenChannel = rgbImage(:, :, 2);
blueChannel = rgbImage(:, :, 3);
% Then do a median filter on each one.  
medianRed = medfilt2(redChannel, [7 7]);
medianGreen = medfilt2(greenChannel, [7 7]);
medianBlue = medfilt2(blueChannel, [7 7]);
% Display the image.


subplot(2, 2, 2);
imshow(medianRed);
title('Red Median Image', 'FontSize', fontSize);
% Then find the pure color pixels.
thresholdValue = 40;
pureRed = redChannel >= thresholdValue & greenChannel < thresholdValue & blueChannel < thresholdValue;
pureGreen = redChannel < thresholdValue & greenChannel >= thresholdValue & blueChannel < thresholdValue;
pureBlue = redChannel < thresholdValue & greenChannel < thresholdValue & blueChannel >= thresholdValue;
% Display the image.
subplot(2, 2, 3);
imshow(pureRed);
title('Red Mask Image', 'FontSize', fontSize);
% Then replace each pure color with the median from that channel.
redChannel(pureRed) = medianRed(pureRed);
greenChannel(pureGreen ) = medianGreen(pureGreen );
blueChannel (pureBlue ) = medianBlue(pureBlue );
% Construct the new color image
rgbImageFixed = cat(3, redChannel, greenChannel, blueChannel);
% Display the image.
subplot(2, 2, 4);
imshow(rgbImageFixed);
title('Fixed RGB Image', 'FontSize', fontSize);

Best Answer

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MATLAB: Change color in image

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