How can I compute the probability of a pixel intensity of the image in Matlab??
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I have an enhanced image and I want to measure the amount of information in the enhanced image using the following metric:
where p(Ie) denotes the probability of a pixel intensity in the enhanced image Ie . now I want to know how to estimate the probability of a pixel intensity. Does anyone know how to do this in Matlab??
2 个评论
Adam
2019-3-19
Which pixel intensity? The probablity of being exactly a given intensity or of being higher than a given intensity or lower? It doesn't make sense without additional context.of what Ie is
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Image Analyst
2019-3-19
ghada:
Use histogram() with the 'Normalization' option of 'probability'.
You might also be interested in the entropy() function (which computes your formula directly from the image), or entropyfilt() function (which does an entropy computation in a moving window).
Demo below:
grayImage = imread('cameraman.tif');
subplot(2, 1, 1);
imshow(grayImage);
subplot(2, 1, 2);
histObject = histogram(grayImage, 256, 'Normalization', 'probability')
grid on;
xlabel('Gray Level', 'FontSize', 20);
ylabel('Probability', 'FontSize', 20);
% Extract probabililty of each gray level into a vector "p".
p = histObject.Values;
4 个评论
Aaron Charles Alday
2020-2-20
Your code didn't work to my matlab sorftware the command window shows this message....why?
"Error in imhist (line 60)
[a, n, isScaled, top, map] = parse_inputs(varargin{:});
Error in Test_Run_2 (line 8)
[pixelCounts, white_value] = imhist(grayImage, 256, 'Normalization', 'probability')"
Image Analyst
2022-5-28
@Aaron Charles Alday, that's not my code. I didn't use imhist, I used histogram. imhist does not take those arguments.
更多回答(2 个)
KALYAN ACHARJYA
2019-3-19
编辑:KALYAN ACHARJYA
2019-3-19
gray_image=rgb2gray(imread('test.jpg'));
[rows colm]=size(gray_image);
[pixelCounts, gray_value]=imhist(gray_image);
prob=pixelCounts(:)./(rows*colm);
prob=nonzeros(prob);
log_prob=log(prob);
DE=-sum(prob.*log_prob);
fprintf('\n The DE value is: %.2f',DE);
Command Window:
The DE value is: 3.50>>
2 个评论
KALYAN ACHARJYA
2019-3-20
编辑:KALYAN ACHARJYA
2019-3-20
Is the problem solved? I have written simple code based on your question. If not. Check the comment of Image Anaalyst sir
Ganesha Thondilege
2022-5-28
I hope this will help you.
grayImage = imread('cameraman.jpg');
subplot(1,2, 1);
imshow(grayImage);
subplot(1,2, 2);
imhist(grayImage);
3 个评论
Ganesha Thondilege
2022-5-28
Try this to get the probabilities of each gray_value
grayImage = imread('cameraman.jpg');
[l,m]=size(grayImage);
subplot(1,2, 1);
imshow(grayImage);
[pixelCounts, gray_value]=imhist(grayImage);
prob=pixelCounts(:)./(l*m);
subplot(1,2,2);
plot(gray_value,prob);
Walter Roberson
2022-5-29
what advantages would this have compared to https://www.mathworks.com/matlabcentral/answers/450942-how-can-i-compute-the-probability-of-a-pixel-intensity-of-the-image-in-matlab#answer_366112
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