The maximum value is not changing even after adding 1
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I have an image with values ranging from [0,255]
It's data is attached below as data.mat below.
I read it and added 1 to its data.
The minimum value of data is changed to 1, but the maximum value of data is still 255.
I don't understand why.
채택된 답변
load data
class(x0_test)
The minimum value an 8-bit unsigned integer can have is 0, and the maximum value is 2^8-1 = 255.
In MATLAB, the convention when performing an operation on a variable of an integer class that will cause the variable to exceed the maximum value for the class (such as adding 1 to an 8-bit unsigned integer whose value is 255) is to cap the value of the variable at the max value of the class. That's why 255 stays at 255 after adding 1.
x = uint8(255:-15:1)
x+1
x+2
x+100
추가 답변 (1개)
The reason is quite simple, your data is stored as an "uint8" which stands for "unsigned integers in 8 bit". The range of acceptable values for that type is from 0 to 255, which makes it ideal to store image data.
y = uint8(255)
y = y+1
x = uint8(243);
x = x+1
This is simply a way that MATLAB handles it. If you were to do the same in C, there will be an integer overflow and the value is changed to "0" instead. MATLAB protects this integer overflow and hence retains the value of 255.
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