Digital watermarking is changing an image in a way so that you can see some text or background image without actually corrupting the image.
Steganography is changiing an image in a way so that you can't see some added text or image with the naked eye, but someone who knows it is there could figure out how to extract that information from the image.
You wouldn't need hardware for either function, it would all be done in software (assuming your images are files and not a hard copy image on a piece of paper). You could probably program such functions using the built in picture tools in LabVIEW. But the Vision add on package would have a lot more functions to make the job easier.
