Re:Moo Card Player
by jay_kyburz on Saturday December 11, 2021 @03:56AM
(#29519536)
hrrm, now I'm wondering how cool it might be to encode some kind of analog signal into a full color spectrum. I guess it would be like taking a photo of an LP and being able to zoom in and read every groove.
Error correction would be a PITA the pixel values would be highly dependent on lighting, camera sensor (even between identical sensors), lens aberration and focus and any post processing the camera does both in hardware and software.
You will most likely have to use only primary colors or something quite close to that which will limit your data density considerably.
The camera would also be a limiting factor. The iPhone 12 has a 12 mega-pixel sensor, so even if you can get exact pixel-for-pixel alignment of the sensor and coded data, you would need to represent 10-50 bits of information in each pixel (eg via color/brightness), for an album, or 1-8 bits for a single song. In practice, you need several pixels per bit, so you would have to scan the code in sections - you couldn't image it at once. At that point, perhaps a tape would be more appropriate than a card.
That is with fairly transparent compression though. You could be a lot more aggressive, and might get something that would work with a single photo.