finding of mse and psnr

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Jitesh Bhanushali 2014-4-11

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https://ww2.mathworks.cn/matlabcentral/answers/125420-finding-of-mse-and-psnr

编辑： Image Analyst 2014-4-11

sir i have attached a code . i want to find mse and psnr of the original image(I) and reconstruted image (y). i have used following code but it gives me error. how to find this parameters??

D = abs(I-y).^2; MSE = sum(D(:))/numel(I)

PSNR=10*log10(255*255/MSE)

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Jitesh Bhanushali 2014-4-11

this is the code

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Answer 1

Image Analyst 2014-4-11

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https://ww2.mathworks.cn/matlabcentral/answers/125420-finding-of-mse-and-psnr#answer_133062

编辑：Image Analyst 2014-4-11

在 MATLAB Online 中打开

psnr.m

Did you cast y and (the badly named) I do double before you did the subtraction? Otherwise negative values will get clipped to zero. For example (7-9).^2 = 0^2 = 0, not 2^2 = 4 like you probably expect. See my attached demo, which you can use if you don't have the new built-in psnr() function that Spandan told us about. Here's the key lines in a snippet:

squaredErrorImage = (double(grayImage) - double(noisyImage)) .^ 2;
% Sum the Squared Image and divide by the number of elements
% to get the Mean Squared Error.  It will be a scalar (a single number).
mse = sum(sum(squaredErrorImage)) / (rows * columns);
% Calculate PSNR (Peak Signal to Noise Ratio) from the MSE according to the formula.
PSNR = 10 * log10( 256^2 / mse);