Question

I have tif image in 16 bit format.
Now I want to convert this data set to an 8 bit rgb image for export as jpg.

If I use

RGB8 = im2uint8(imageData);

then I have a matrix with only 255 values, which is wrong since the histogramm has only values around 0 to 16000 with the maximum at 700 (max value of 16 bit is about 65500)

Also I want to adjust the gamma level to 0.45, which means that I do not want a linear mapping of values to brighness in each color.

How would I do that with matlab?

Answer 1

I solved it now with the following code:

% reads 16 bit tif image
imageRGB16 = imread(importName);
% convert to 14 bit 
imageRGB14 = imageRGB16 * 4;
% apply gamma correction
imageRGBGamma = imadjust(imageRGB14,[],[], 0.45);
% convert to 8 bit
imageRGB8 = im2uint8(imageRGBGamma);
% imshow(imageRGB8);
% export to jpg
imwrite(imageRGB8,exportImportName,'jpg', 'Quality', 90)

The resulting images have the same colors and brightness as he original camera images viewed with a special software which is what I wanted.