如何更改图像的像素值范围？

Question

I have grayscale images with values in the range [0-65533]. I've never see this before. What is this range?

I want to scale the values to the range [0-1200]. I tried the imadjust function but it does not work because this function required values between 0.0 and 1.0 only.

How can I use imadjust to scale these values properly?

Answer 1

That range of values suggest that your grayscale image contains unsigned 16-bit integers, ie it is of type uint16 (integer values from 0 to 65535). The documentation for imadjust states that it supports images of this type, but it's still a little tricky to get the results you want.

Regardless of the image type, the contrast limits are always expected to be in the range [0 1] . This will require you to rescale them yourself by dividing by 65535 :

scaledImage = imadjust(uint16(inputImage), [0 65533]./65535, [0 1200]./65535);

Note that I also added the conversion uint16(...) just to make absolutely sure the input image is that type when passed to imadjust . If your input image happened to be converted to type double first, imadjust would expect the values to be in the range [0 1] for the image as well, which would give you an incorrect output in this case.

Answer 2

如果我理解正确，则可以执行以下操作：

newimage=1200.*oldimage./65533;