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If you want watermarks to survive jpeg compression, you have to do DCT block manipulation, not just individual pixel values.
by jonatron 6y ago
If you want watermarks to survive jpeg compression, you have to do DCT block manipulation, not just individual pixel values.
- betterunix2 6y agoOr you can work in the frequency domain of the entire image instead of DCT blocks, which gives you a lot more room to work around various compression issues. I would also suggest that an error correcting code is helpful.
- im3w1l 6y agoDoes this survive cropping by not-multiple-of-8?
- jonatron 6y agoWhen you decode, you can start from offsets (eg 4,4) rather than 0,0.