Saving labels as an image file

Hello,

I have segmented an image and created a matrix which gives each segmented object a unique label (similar to the matrix resulting from 'bwlabel' but many of the objects touch). I would like to save the label matrix so that I can later read it back in for further processing.

I have tried saving the matrix using 'imwrite', however the result is a binary image with all labels set to 255 rather than a grayscale leaving each with a unique identifier. I have tried saving it as a jpg, tif, and bmp, all of which give me the same results. When I use the 'label2rgb' function, the individual objects save just fine, but then I can't turn the image back into labels easily.

Thank you!

Jocelyn