how to obtain rms error

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Mahua Nandy(Pal)
Mahua Nandy(Pal) 2012년 10월 11일
댓글: Image Analyst 2020년 1월 18일
Please tell me how to calculate the rms error in image registration?

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Image Analyst
Image Analyst 2012년 10월 11일
Wouldn't it just go like this
difference = single(image1) - single(image2);
squaredError = difference .^ 2;
meanSquaredError = sum(squaredError(:)) / numel(image1);
rmsError = sqrt(meanSquaredError);
Of course you could compact that all into one line if you want.
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MAT-Magic
MAT-Magic 2020년 1월 18일
편집: Image Analyst 2020년 1월 18일
@Image Analyst, can I use this formula for two vectors having same length?
difference = single(image1) - single(image2);
squaredError = difference .^ 2;
meanSquaredError = sum(squaredError(:)) / numel(image1);
rmsError = sqrt(meanSquaredError);
?
Image Analyst
Image Analyst 2020년 1월 18일
Yes, you can, but I'd use mean() instead of sum to simplify it:
differenceImage = single(image1) - single(image2);
squaredErrorImage = differenceImage .^ 2;
meanSquaredError = mean(squaredErrorImage(:)) % A scalar
rmsError = sqrt(meanSquaredError)
And if they're vectors of the same shape (row or column) then you don't even need the (:).

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추가 답변 (1개)

Daniel Shub
Daniel Shub 2012년 10월 11일
편집: Daniel Shub 2012년 10월 11일
Just to be a little bit difference. If you have the DSP system toolbox you can do
step(dsp.RMS('Dimension', 'all'), x)
where x is your error signal. So in the case of two imagines (image1 and image2)
image1 = randn(128);
image2 = randn(128);
x = image1-image2;
  댓글 수: 6
Ishara Nipuni
Ishara Nipuni 2019년 1월 25일
I calculated the RMS value of my image registration algorithm by using your code. But I can't understand how to do a validation for my registration algorithm with th RMS value. Can you tell me please how can I com to conclusions about the accuracy of my registration algorithm with the use of RMS values?
Ishara Nipuni
Ishara Nipuni 2019년 1월 25일
I calculated the RMS value with getting the same image as image1 and image2. But the value was not zero. But I think that it should be zero. Can you please explain me about it?

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