Hi, i want to binarize an image by using thresholding.how to obtain threshold 25% of the gray intensities? (25% of the lower gray intensities are discarded) please gudie me.
MATLAB: How to obtain the threshold 25% of the gray intensities
binarizeimage processingthresholding
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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.
There are multiple meanings of "thresholding" that might be appropriate.
One meaning:
NewImage = YourImage >= T1 & YourImage <= T2;Another:
NewImage = YourImage .* (YourImage >= T1 & YourImage <= T2);
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