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Why do we transfer the image into double?

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I saw a lot of image processing examples and before conducting any analysis the image is transfered into double. Is it essential? and what is the benefit from doing so?

Accepted Answer

Image Analyst
Image Analyst on 5 Apr 2020
No, it's usually not. But sometimes it is, like if you want to use conv2(). It has to do with how MATLAB likes to multiply variables of different classes.
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Image Analyst
Image Analyst on 5 Apr 2020
Other than conv2(), I can't think of any off the top of my head. But you obviously must have had some cases in mind because you're the one who brought up the question. Care to share those cases?

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More Answers (1)

Paul Hoffrichter
Paul Hoffrichter on 4 Dec 2020
MATLAB when using mixed mode arithmetic, will try to save memory.
250 + 10 = 260, right?
>> x =double(250) + uint8(10);
>> x
x =
uint8
255
In other languages, like C/C++, the rule is to maximize precision. Avoid mixed mode arithmetic unless you need it. There is no error or warning provided, by default, in the above code.
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