How to convert the int16 medical image in to unit16 image without losing any information..?

Hi I am working on the medical image whose intensity range is ranging from -2000 to 4000, I want to convert this range into non-negative range (starting from zero) without losing any information. Please help me to solve this problem. Thanks in advance

Answer 1

[Walter Roberson]

shifted_data = uint16(YourData + 2000);

However, the range of values you are using tells me that you are looking at Hounsfield units, and if you want to do any calculations based upon those (rather than just displaying the image) then you will need to remember to convert back to signed and subtract off the 2000 again.

[harshal j]

Thank You so much, Walter, for your answer. Yes, I am looking at Hounsfield unit. I am trying to apply nonnegative factorization to images but because of negative values, the algorithm is not applicable to these images. Is there any loss of information when we add minimum value in each pixel to convert it into non-negative values. I am facing problem in converting the pixel values again into Hounsfield unit and if we convert it by using (HU = pixel_value*slope - intercept) then HU values of pixel obtain from the MATLAB are different from the HU value of the same pixel from dicom viewer. I am not getting why it is giving different values, Please help me to solve this problem.