You upload an image, but the image hoster unhelpfully reëncodes your image as a medium quality lossy JPEG. How much data can you reliably losslessly store in an image in this scenario?
Use QR codes, or other two dimensional bar code format with error correction. Treat the Y Cb Cr channels (almost) independently: the C channels are half resolution and require Y to be positive.
Each channel is more than one bit deep, so one can "stack" several black and white images on top of each other. The further down in the stack, the less significant bits, suffer more degradation: use more error correction.
Inspired by facebook.
No comments :
Post a Comment