LSB watermark and LSB replacement difference?

Is those two are the same concept or any relationship between them? I search online and could not find any useful information. Thanks

Answer 1

[Walter Roberson]

Watermarking might involve using lsb embedding.

The difference between watermarking and steganography is not a big one. Watermarking involves embedding information for the purpose of establishing proof of ownership, or proof that the file has not been altered, or the like. Steganography involves embedding secret information and retrieving it, for whatever reason you might want to do that. Generally speaking, watermarking is permitted to have obvious visible effect on the image but steganography should ideally have no obvious visible effect; however for some of the purposes of watermarking, it is also preferred to have no obvious visible effect. For some of the purposes of watermarking (such as anti-forgery) the embedded information does not have to "convey" anything, it just has to be cross-checks to establish that the image is untouched. Steganography, on the other hand, is always about conveying information. When the purpose of watermarking is to establish ownership, such as hiding a message such as "Copyright 2016 by Jason", then that purpose of watermarking is identical to steganography of hiding the message "Copyright 2016 by Jason".

Steganography concentrates more on hiding information. Watermarking typically concentrates more on authentication and integrity -- and sometimes watermarking wants to be obvious, such as those sample images from Shutterstock that have "Shutterstock" scrawled on them to make it obvious that the sample image has not been paid for. Shutterstock might well have two watermarking procedures, one that it applies to paid images and one that it applies to unpaid images, to allow it to crawl the internet and find people who are not paying and to track the spread of its images.

Other than that, the techniques can be very very similar. It is more a question of what you do with the information you embed than a matter of different ways of embedding.

[Jason]

Awesome answer. Thank you for typing one word by word for answering my questions with very details information

[Image Analyst]

I do have an LSB watermarking demo that you've probably run across already, but I'm attaching it anyway. The watermark has various degrees of visibility depending on what bitplanes you encode it into.

I also have a text encoding demo in my File Exchange. We can't post anything that's called steganography or the Mathworks gets nervous and might take it down.