Hi,
I am wondering how do you go about comparing the pixels of each images with subtraction and return the image with higher pixel difference. If subtraction works but rgb values goes negative, will it just display a black screen?
MATLAB: Comparing 2 images by subtracting pixels and what happen if rgb values goes negative
imageimage acquisitionimage analysisimage processingimage reconstructionimage segmentationimages
Related Solutions
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);
D_coder, try this:
clc; % Clear the command window.
clearvars;close all; % Close all figures (except those of imtool.)
workspace; % Make sure the workspace panel is showing.
format long g;format compact;fontSize = 20;grayImage = imread('cameraman.tif');subplot(2, 2, 1);imshow(grayImage);title('Original Image', 'FontSize', fontSize);sortedGrayLevels = double(sort(grayImage(:), 'descend'));% Sum up the energy from most energetic to least energy.
percentage = cumsum(sortedGrayLevels);percentage = percentage / percentage(end);subplot(2, 2, 2);plot(percentage, 'b-', 'LineWidth', 2);grid on;title('Cumulative Distribution Function', 'FontSize', fontSize);% Find the brighter 75%
% Find the gray level where 75 percent is
index75 = find(percentage >= 0.75, 1, 'first')grayLevel75 = grayImage(index75)% threshold the most energy 75%
binaryImage = grayImage > grayLevel75;subplot(2, 2, 3);imshow(binaryImage);title('Brighter 75%', 'FontSize', fontSize);% Find the darker 75%
% Find the gray level where 75 percent isindex75 = find(percentage >= 0.25, 1, 'first')grayLevel25 = grayImage(index75)% threshold the most energy 75%binaryImage25 = grayImage < grayLevel25;subplot(2, 2, 4);imshow(binaryImage25);title('Darker 75%', 'FontSize', fontSize);
Each binary image will contain 75% of the energy. It just depends if you wanted to start with the darker pixels and work brighter, or start with the brightest pixels and work darker.
Best Answer