I'm trying to edit the colors of individual pixels in PNG image file (if there's another format that's easier to edit than PNG, I can try that). I have the student version of MATLAB with no toolbox add-ons. Thanks!
MATLAB: How to change the color of an individual pixel in a downloaded image
colorimageimage processingpixel
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That's not a gray scale image you attached, it's an RGB image. So try this
rgbImage = imread('C1fig.jpg');whos rgbImagesubplot(2, 1, 1);imshow(rgbImage);title('Original RGB image C1fig.jpg');axis('on', 'image');impixelinfomask = rgbImage(:, :, 1) == 0;% Extract the individual red, green, and blue color channels.
redChannel = rgbImage(:, :, 1);greenChannel = rgbImage(:, :, 2);blueChannel = rgbImage(:, :, 3);redChannel(mask) = 255;greenChannel(mask) = 0;blueChannel(mask) = 0;% Recombine separate color channels into a single, true color RGB image.
rgbImage = cat(3, redChannel, greenChannel, blueChannel);subplot(2, 1, 2);imshow(rgbImage);axis('on', 'image');impixelinfotitle('Altered RGB image');
If it really is a gray scale image, you can try this:
grayImage = imread('C1fig.jpg');if ndims(grayImage) == 3; grayImage = rgb2gray(grayImage);endwhos grayImagesubplot(2, 1, 1);imshow(grayImage);title('Original image C1fig.jpg');axis('on', 'image');impixelinfomask = grayImage == 0;% Initialize the individual red, green, and blue color channels.
redChannel = grayImage;greenChannel = grayImage;blueChannel = grayImage;redChannel(mask) = 255;greenChannel(mask) = 0;blueChannel(mask) = 0;% Recombine separate color channels into a single, true color RGB image.rgbImage = cat(3, redChannel, greenChannel, blueChannel);subplot(2, 1, 2);imshow(rgbImage);axis('on', 'image');impixelinfotitle('Altered RGB image');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; endendrgbImage = 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.BoundingBoxcroppedImageRGB = 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);
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