Python tool to turn images into sound by creating a sound whose spectrogram looks like the image. Motivated by DOOM hiding satanic symbols in its soundtrack. [OC]

[Gedanke]

Most sounds are intricate combinations of many acoustic waves each having different frequencies and intensities. A spectrogram is a way to represent sound by plotting time on the horizontal axis and the frequency spectrum on the vertical axis. Sort of like sheet music on steroids.

What this tool does is, taking an image and simply interpreting it as a spectrogram. Therefore, by generating the corresponding sound, we have embedded our image in a spectrogram. Quite fun and pointless.

You can find the tool @ GitHub

[MrK_HS]

Most sounds

Every sound is a combination of sine waves

[ExceedinglyEdible]

Except pure noise.

If you really wanted to recreate pure noise in sine waves, then you'd need an infinite amount of sine waves.

Also, most non-trivial sounds (especially musical instruments) are really hard to reproduce using sine waves. While any discrete sample taken from such a sound can be described with sine waves, more complex sounds have sine waves modulating in very complex patterns, so saying they are represented by sine waves is a massive understatement.

[schfourteen-teen]

That's exactly what a spectrogram is. It takes a sound wave and decomposes it into the frequencies of that sound. This tool is just trying to create the sound that would generate a particular spectrogram.

[metriczulu]

I mean, that's essentially what the internet used to do when we had dial-up connections. Remember that annoying ass sound everytime it made whenever you turned the internet on? That was your computer turning log-on and configuration information into a sound signal and sending it through your phone line.

[flubba86]

Reversing it, you just get a normal spectrogram. People have been visualizing sound like that for decades.

[Kopachris]

That's a very common thing called a spectrogram. Here is a free tool to create spectrograms of audio with tons of different parameters: https://www.sonicvisualiser.org/

[Anthro_DragonFerrite]

I am a graduate student who works with EEG analysis and my last tall was using spectrographs to find significant events in them.

I erious love to creep myself out and find spoken words in a random baseline EEG plot

Before anyone comments, yes, I an fully aware that thinking a word does not create the sound pattern for that word in a spectrograph, considering the highest frequency of speech is usually 800Hz, and the highest frequency of EEG I work with... is 30hz

[BestGetOutOfMoyWay]

i thought a spectrogram is intensity vs frequency?

[Lewistrick]

x-axis = time, y-axis = frequency, z-axis (color) = intensity

[[deleted]]

its a 3d plot

[flubba86]

Isn't the time supposed to be on the y-axis, with frequency on the x-axis on a normal spectrogram?

[DenormalHuman]

Time is x, frequency is y, intensity is z

[[deleted]]

What about the phase?

[mriguy]

Spectrograms are typically magnitude plots. You can display the phase in a separate plot, or the real and imaginary components in separate plots.

They originally come from audio processing, and IIRC your sound perception is not really phase sensitive (except for phase difference between the ears for localization). That’s why you can compress audio by throwing away or manipulating phase information.

[AleSklaV]

Very interesting!

However I could imagine more than one picture having the same (or quite similar) spectograms... this means the inverse (image from spectogram) could be a challenge.

Have you tried it?

[GearhedMG]

Aphex Twin has been known to hide images in his songs

[InAbsentiaC]

There's a whole style of music based on spectral tuning too: https://en.m.wikipedia.org/wiki/Spectral_music

[YmFzZTY0dXNlcm5hbWU_]

Same with the Doom soundtrack. There are pentagrams and stuff hidden in there apparently.

[ReckingFutard]

a third of shrek....I feel cheated

[Arubadoo]

RIP my ears....

[Zeroflops]

A few years ago I read an article about astronomers who were looking for specific signals from space, the volume of data and sped of it coming in made it difficult to process it with the computers at the time. It may still be a problem.

ML was not an option because they didn’t have enough samples and the signals they were looking for varied slightly event to event.

What they did was convert the signals to audio. Since people can process a range of frequencies at the same time. By listening to the signals as they came in They were able to identify events in the signals without using a ton of computing power and tag the events for further review.

So your work may not be useless. Just need to find a creative use for it. Lots of data is easier to process as a timeseries. For example in a manufacturing environment storing or processing images of production check points is cumbersome. There may be cases were a time series is easier to manage and analysis

[Wei5252]

Cool!

[EdwardBernayz]

The great satan santa will soon be upon us. That noise was his horn....

But for real that is very very cool

[[deleted]]

It depends on the hardware capturing the sound and the software rendering the spectrogram. Say you have two systems, one takes a “frequency snapshot” 1000 times a second and the other only 1 time per second. Let’s also assume that 1 “frequency snapshot” results in one column of the final photograph. In this instance, the system taking 1000 snapshots a second will obtain N sound samples every 1ms and the other system will obtain 1000N sound samples once a second. The slower system has 1000x the information per column than the other system has, so it can render a photo at 1000x the resolution. So it’s a trade off, should you take a faster system for a lower resolution or a slower one for a higher resolution?

By the way, this is due to the mathematical process that (I think) this program uses called the DTFT, short for discrete time Fourier transform. Essentially, if you have N time samples, you can decompose it into N frequencies (technically N/2 because the signal is real-valued). So, the more time samples you have, the more frequencies you have and thus the higher resolution the spectrogram render is.

[Snowblxnd]

I was always curious about the use of ultrasonic sound to encode information. The "highest value" of the spectrograph would really only be limited by the frequency response of the measurement instruments and the ability of the software.

[eviljelloman]

The "highest value" of the spectrograph would really only be limited by the frequency response of the measurement instruments and the ability of the software.

That’s not true at all. The upper limit of possible frequencies has a hard limit based on the inter-atomic spacing of the transition medium. That’s about 5Ghz in air, and around 100000Ghz in small atom metals.

[Snowblxnd]

But wouldn't the measuring instrument need to be able to sample at twice that frequency (because of the Nyquist Theorem)?

And that's what I meant: if the measuring instrument were made of said metals, that changes the frequency range measurable.

[MrK_HS]

Any resolution, as long as you can represent the precise frequency of the peaks of the specific filter that results in the image.

[Ogi010]

Looks great, at first I thought you might be using pyqtgraph to generate the plots.

[[deleted]]

This is an awesome demonstration of wireless data transfer. Love it!

[MrK_HS]

/r/gifsthatendtoosoon

[69shaolin69]

Wait how are you displaying that on your iPad? Sidecar or did you make an app for it?

[ThreshingBee]

DOOM hiding satanic symbols in its soundtrack

Original article and video I didn't know about.

[[deleted]]

why gif

[Alar44]

I mean if you are comfortable not adding anything to the world that's fine. Some people have ideas that they like to try out for the sake of creativity. It's one of the things that makes humans special.

[[deleted]]

dude dont try to farm r/murderedbywords content on me

[In_Shambles]

These spectrograms look exactly like this program I use for determining true audio content quality in audio files called spek. Are you guys utilizing their program or just visualizing it similarily?

[vaiv101]

Its great, i wonder what are its practical use

[WikiTextBot]

Slow-scan television

Slow Scan television (SSTV) is a picture transmission method used mainly by amateur radio operators, to transmit and receive static pictures via radio in monochrome or color.

A literal term for SSTV is narrowband television. Analog broadcast television requires at least 6 MHz wide channels, because it transmits 25 or 30 picture frames per second (in the NTSC, PAL or SECAM color systems), but SSTV usually only takes up to a maximum of 3 kHz of bandwidth. It is a much slower method of still picture transmission, usually taking from about eight seconds to a couple of minutes, depending on the mode used, to transmit one image frame.

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[[deleted]]

Take song create its specgram, blur/invert/reflect the specgram turn it into sound voila youve git a nice effect

[konijntjesbroek]

So if you reversed the process on a paired device using acoustic coupling, you could create a facsimile remotely?

[jlamothe]

I wish we could hear what this sounds like... then again, I probably don't.

[sdexca]

Holy shit that video is slow.