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syvaidya / openstego

OpenStego is a steganography application that provides two functionalities: a) Data Hiding: It can hide any data within an image file. b) Watermarking: Watermarking image files with an invisible signature. It can be used to detect unauthorized file copying.
https://www.openstego.com
GNU General Public License v2.0
1.13k stars 206 forks source link

Feedback : Digital watermarking (Beta) #24

Open DirectuX opened 6 years ago

DirectuX commented 6 years ago

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 commented 5 years ago

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 commented 5 years ago

@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 commented 4 years ago

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 commented 4 years ago

@bluefinch83 Please, open a new issue for this.

manvydasu commented 3 years ago

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

DirectuX commented 3 years ago

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

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