How can i store double precision data after completeing idct2 (on an image) into an image format such as jpeg or tiff without losing information?

Hi everyone,

I am trying to implement a DCT based steganography on images using the LSB substitution method. After transforming the cover image into the DCT domain and embedding the message bits, i performed an inverse dct transform which gives double precision data.

I need to write this data into the supported tiff or jpeg formats. When using imwrite to do this, as it does not support double data it is rescaling and storing in the default uint8 data format.

In the extraction phase where once again a dct transform is done on the stego image , i am unable to retrieve the complete hidden data as there was information loss while using imwrite. Is there any way to store the data as an image without losing any of it?

Regards, Harsha

Answer 1

[Image Analyst]

Use save() to save it as a MATLAB proprietary format. Will work as long as you plan on using that saved image only in MATLAB.

[Subhadeep Koley]

But I want the image to be viewed in any normal image viewer not only MATLAB. Thnaks