How to transform SoundWave Picture to sound? I would like to recreate a sound from a picture of a soundwave.

But i see a lot of theorical question.

And im not sure its possible.... 

I mean, it is possible to create a sound... 

But to make the sound as close as possible of the original one, sound a bit harder.

Most of the time when you see soundwave as art... 

It's really time compressed.

I would love to have a tatoo of the soundwave of someone important to me that say a word to me. 

And then with my smartphone point the camera at the tatoo and hear it again.

But i have a lot of question about this.

First how can i get the periodicity?
Per pixel i will probably got a lot of periode. 
How can i decide the lenght of my whole song? 
I have a sound wave but no legend. so it can be 1s or 160s compressed i can never know....

Let's say i cheat and decided my application always says from start to end of my soundwave i have 1s (1s is enough for a 'I love you' for exemple)

Ok so i have my length total so with open cv i can check my image and reconise bar height every pixel.
And then with my pixel length and the fact i know it's one second i can start to generate sound.

But how can i decided.... the corresponding value to the Heigh in pixel? I don't have frequency value correspondance. 12px heigh can be 20Hz as 20 000Hz

Ok let's say i define a value to the max height of my sound wave to the real value of my sound.
Cause i use a sound i choose. 
So i can set a reference value and use it to get other value.

I now parse a picture to get a compressed sound and i have some value of Hz in an intervall of second.

Lets say i have a 10cm tatoo of a 1s sound.
each cm is 0.1s

And in each cm i can make like... 10 bar maybe 20 (one bar is 1mm or 0.5mm possible in tatoo right?) 
Let say 20 ...

so i have info of Hz every 
0.005s

and let say i decide i start up and and bottom
i hav two info in 0.005s the up and bottom one
So i have one info for 0.0025s

That make a sound at 400Hz...
And... classical sound are know to be around 44 100Hz.... 

Will the sound i produce be at little close to the real one? 
Or does it will only be a little noise?

(English is not my mother tongue feel free to improve i will try my best to reformule if you didn't understand something)
I don't think "I love you" is doable with a sound wave image, because that's already very roughly about 200 cycles of the fundamental frequency of the voice, and you need also the harmonics so that it sounds right and can be understood. Too much horizontal resolution is needed to pack that into a tattoo.

You could probably pull it off as a spectrogram.

I've seen ads for a commercial service that presumably stores at a server a database of sound clips each associated with a sound wave image. Then their phone app sends the tattoo photo to the server and plays back the sound clip associated with the image that most resembles the tattoo photo. Technically that's not far different from having the sound clip number tattooed as a bar code.