I just ran into https://skinmotion.com/ which sells "Soundwave Tattoos".
My gut says tattoos cannot have high enough resolution to actually encode 15s of audio - even at speech quality.
Reading all the "FAQ" items I get the impression that the company knows the tattoos are "unplayable" except with their specific App.
This all suggests that their app merely detects the shape, making a fingerprint and looking up matching samples in their cloud database. The match can be crude, as long as there is sufficient confidence gap to distinguish from (expectable) similar matches.
I have two questions:
has anyone done the maths to rule out/confirm that tattoos cannot actually encode the required data volume
does anyone know how to approximate at what database size (number of registered, activated tattoos) there would be, say, a threshold probability p (say, 10%) of the app playing the wrong sample when scanning any particular tattoo?
I'm aware many parameters are highly implementation-dependent, and likely patented information. However, I also know that mathematics has general formulae about information representations, entropy and compression vs. information loss. So I figure mathematically there should be an upper bound on the performance of a service like this.