export matrix as image?

Good Morning Sir!

    I am trying to watermark some value in a 404x474 RGB
image. Exactly watermarking in the blue color matrix(unsigned integer type). converted the matrix into double type and watermarked the value. want to export this double type matrix as an image without loosing any value. So that on the next phase of watermark extraction I can retrieve the matrix from the image.

How to perform this?

Answer 1

[Jan]

You can store an image as WxHx3 array using IMWRITE. But the values are either UINT8 or DOUBLE values. You can store an RGB array of type DOUBLE using 16-bit precision per color channel. But this does not allow to store the image "without loosing any value". I do not know animage format, which stores the values with 64 bit precision per channel.