How can I save an image and keeping the double precision values??

I have a problem as follows:

I'm working on a data hiding code, using a cover image and a secret message to embedd in it, after applying the dct2 on the cover image i added the secret file, but after adding the file, the cover image represented as a matrix has a double values, so the problem is when i save the file as a image to send, matlab doesn't use a double presision values when saving the image, but integers.

so how can I save an image and keeping the double precision values??

Answer 1

[Jan]

You can't. Most image file formats are defined with integer types. You can write single precision data to TIFF files, but as far as I know no doubles. JPEG, GIF and PNG work with integer types only. So this is not a problem of Matlab.

[Abdallah Talafhah]

what can I do to save the image that is a double precision basis?

[Jan]

You can save a binary file using fwrite(). But than these data are not interpreted as image file anymore.