How to convert a range of pixel values to another range(0-255) ?

I have a DICOM image in which pixel values ranges from -2000 to 2666. I need to convert those values to ones which are within the grayscale range. How can i do this?

Answer 1

[Image Analyst]

Try mat2gray(), which converts any matrix to a 0-1 range. Then multiply by 255 and cast to uint8 if you want a uint8 data type.

uint8Image = uint8(255 * mat2gray(yourDicomImage));

[ali ali]

i had problem that dealing with above and i solved it by use uint8Image = uint8(255 * mat2gray(yourDicomImage)); code thanks ..thanks

phd stu :Ali. A .S

[tarek bentahar]

u can also normalize your image in 0 to 1 range, then uint8(normalizedimage*255).

[Image Analyst]

You can also use the new rescale() function instead of mat2gray() if you want.

Answer 2

[Jan]

Img1 = randi([-2000, 2666], 640, 480);
Img2 = round((Img1 + 2000) * (255 / 4666));

[cecilia rodrigues]

Hello Jan,

Why do I get different pixel value results when I use the formula you suggested above and the wcodemat(image,255,'mat',1) function?

Shouldn't wcodemat also scale from 0 to 255?

Thank you very much!