Change bit depth for a PNG image

hello , i have a dataset of images with 12 bit represantation and i want to know if it is possible to convert them to 8 bit representation . thanks

Answer 1

[Image Analyst]

Yes. How do you want to do it? Scale linearly? Or take the upper or lower 8 bits and throw away 4 bits? Maybe you can try mat2gray().

[berkaoui sara]

i have images in PNG format with 12 bits , i use the imcrop function to extract 128*128 regions from these images , when i get the wanted region , i note that there is a visual difference betwenn the original and the cropped image. I thought may be because the original image is high resolution, so I thought to change the bitdepth. do you think this is right?

[Image Analyst]

The number of gray levels (bit depth) and the lateral size of the image (number of rows and columns) are unrelated/independent. You can adjust each on it's own. But I don't know what you want to do. Why do you think that you want to change the bit depth (number of intensity gray levels)? And what does that have to do with the pixel being high resolution (10 megapixels or whatever)?