Feedback : Digital watermarking (Beta)

[DirectuX]

Hi, thanks for this nice tool, and:

(I have read issues #17 #11 #10 and This:"If a digital watermark distorts the carrier signal in a way that it becomes perceivable, it is of no use." there:https://www.openstego.com/concepts.html

Here is some feedback :
1/ it is clearly visible that the jpg image file has been modified, especially when picture has large plain surfaces
2/ openstego.ini is created in the user folder but file is empty (why ?)
3/ can't change jpeg quality (consequence of 2/ , may solve 1/) how to ?
4/ metadatas are gone (there is a workaround = put them after, but the convenient way would be that just the picture data is modified, enhancement?)
5/ on one png file, transparency is gone after watermarking
6/ enhancement : select allowed zones on the image to be watermarked, when some big part can easily be cropped, one can skip this zone.

Config=
OpenStego v0.7.2
Java VM v8
Windows v8.1 64b

[Eyremba]

5/ on one png file, transparency is gone after watermarking

This is a general issue of watermarking. As far as I know, Digimarc (The watermarking tool of Photoshop) does also not work with transparency files, for example with png files which contain transparent elements.

[DirectuX]

@Eyremba:
Openstego is specialized in steganography, one can assume it would do better than the average watermarking software. Suggestion: backup alpha channel, apply watermark, restore alpha , would it work? Think of combination with feedback 6/

[bluefinch83]

Hello, I'm having issues recovering the watermark from a compressed image. So, I embed a watermark in an image and then resized it. No matter how small the resize was, even a 1% change in size made the watermark unreadable. I tried this with both jpg and png files, and neither worked. Does the watermark just not handle resizing well?

[DirectuX]

@bluefinch83 Please, open a new issue for this.

[manvydasu]

@DirectuX
Which research paper is the algorithm for invisible watermaking based on?

[DirectuX]

@DirectuX
Which research paper is the algorithm for invisible watermaking based on?

oh please, ask Samir, I'm not the developer.