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Stephen

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13 Mar 2011 Screenshot Hiding image in sound (im2sound) Converts an image into a sound file. Played through a spectrum analyser, the image is revealed. Author: Stephen image, sound, hiding, converter, image processing, physics 25 6
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29 Feb 2012 Hiding image in sound (im2sound) Converts an image into a sound file. Played through a spectrum analyser, the image is revealed. Author: Stephen

Hi, sorry for the late reply.

With regards to the distortion the input parameters I found to have the most significant were the 'f_sample' (sampling frequency) and 'sample_t' (sample length).

The settings I found to be most suitable are listed at the top of the m-file. They are:
f_sample = 44000 (Hz)
f_low = 40 (Hz)
f_high = 6000 (Hz)
amp_mod = 0.00002
sample_t = 10 (seconds)

I used that sampling frequency because I believe it is the one used on music CDs. Alternatively, increasing t_sample will also improve image quality (decrease distortion), but then you end up with longer files.

I don't use any plugins with Sonic Visualiser, just the vanilla version from their website. I open the audio file, then click 'Pane', then 'Add Spectrogram'. Next I resize the spectrogram using the silver wheels on the bottom right of the black window, so the image is vaguely the same aspect ratio as the original image. I use the controls on the right of the image to fine tune the image till it appears clearest. With a sample_f = 44000Hz and t_sample = 10s I find the best settings in Sonic Visualiser are:
'Color' - 'Default'
'Scale' - 'dBV^2'
'Window' - '8192' '93.75%'
'Bins' - 'All Bins' 'Linear'

Finally I change the contrast using the dial to the right of the 'Scale' controls.

I'm not sure what you mean by "In which application this technique is used by artist's such as Aphex Twin". I assume you're asking which software he used to achieve this effect. Unfortunately I don't know how he did it, but as far as I can tell, however he did it the result is the same as using this m-file.

I've not really considered the applications of this technique beyond the entertainment value of being able to hide images in sound - such as putting them in songs as an 'Easter Egg'. I suppose you could encode secret messages at frequencies not audible to human hearing, but it wouldn't be very secure as this is very easy to decrypt. That would be more as a fun way of sending messages between friends than anything else.

I hope all that makes sense and answers your questions.

Stephen

09 Oct 2011 Hiding image in sound (im2sound) Converts an image into a sound file. Played through a spectrum analyser, the image is revealed. Author: Stephen

Hi, this m-file doesn't allow you to convert from sound to image, but you can do this using a spectral analyser. The one I like is called Sonic Visualiser (http://www.sonicvisualiser.org/).

If the sound has an image encoded in the frequency space as a function of time you should be able to see the image in the output.

I hope that helps.

16 Sep 2011 VCAPG2 VCAPG2 is DirectShow based video capture DLL that support various types of video capture cards. Author: Kazuyuki Kobayashi

This has been really useful. Worked straight away with my Logitech cam.

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29 Feb 2012 Hiding image in sound (im2sound) Converts an image into a sound file. Played through a spectrum analyser, the image is revealed. Author: Stephen Stephen

Hi, sorry for the late reply.

With regards to the distortion the input parameters I found to have the most significant were the 'f_sample' (sampling frequency) and 'sample_t' (sample length).

The settings I found to be most suitable are listed at the top of the m-file. They are:
f_sample = 44000 (Hz)
f_low = 40 (Hz)
f_high = 6000 (Hz)
amp_mod = 0.00002
sample_t = 10 (seconds)

I used that sampling frequency because I believe it is the one used on music CDs. Alternatively, increasing t_sample will also improve image quality (decrease distortion), but then you end up with longer files.

I don't use any plugins with Sonic Visualiser, just the vanilla version from their website. I open the audio file, then click 'Pane', then 'Add Spectrogram'. Next I resize the spectrogram using the silver wheels on the bottom right of the black window, so the image is vaguely the same aspect ratio as the original image. I use the controls on the right of the image to fine tune the image till it appears clearest. With a sample_f = 44000Hz and t_sample = 10s I find the best settings in Sonic Visualiser are:
'Color' - 'Default'
'Scale' - 'dBV^2'
'Window' - '8192' '93.75%'
'Bins' - 'All Bins' 'Linear'

Finally I change the contrast using the dial to the right of the 'Scale' controls.

I'm not sure what you mean by "In which application this technique is used by artist's such as Aphex Twin". I assume you're asking which software he used to achieve this effect. Unfortunately I don't know how he did it, but as far as I can tell, however he did it the result is the same as using this m-file.

I've not really considered the applications of this technique beyond the entertainment value of being able to hide images in sound - such as putting them in songs as an 'Easter Egg'. I suppose you could encode secret messages at frequencies not audible to human hearing, but it wouldn't be very secure as this is very easy to decrypt. That would be more as a fun way of sending messages between friends than anything else.

I hope all that makes sense and answers your questions.

Stephen

28 Feb 2012 Hiding image in sound (im2sound) Converts an image into a sound file. Played through a spectrum analyser, the image is revealed. Author: Stephen Chetan More

understood how to use sonicc visualiser. Thaks...
Got the original image reappeared,
but not same, some distortion are there, can we do something to remove distortions..
I am not getting what are the effects(use) of pluginsin the sonic visualiser.Tell which plugins are used for WINDOWS?.
In which application this technique is used by artist's such as Aphex Twin.. as told by you.
What will be the applications of this technique?

23 Feb 2012 Hiding image in sound (im2sound) Converts an image into a sound file. Played through a spectrum analyser, the image is revealed. Author: Stephen Chetan More

I am not getting, how to use sonic visualiser to reconstruct image from sound file.Will you give me some guidance, please..

18 Dec 2011 Hiding image in sound (im2sound) Converts an image into a sound file. Played through a spectrum analyser, the image is revealed. Author: Stephen Chetan More

y = wavread('filename') loads a WAVE file specified by the string filename, returning the sampled data in y. The .wav extension is appended if no extension is given. Amplitude values are in the range [-1,+1]
but i tried by using this but i am not getting to get exact brightness levels of pixel...
Please to help me related to this.
Just i wanna match matrix values..same as that of we got from image.

09 Oct 2011 Hiding image in sound (im2sound) Converts an image into a sound file. Played through a spectrum analyser, the image is revealed. Author: Stephen Stephen

Hi, this m-file doesn't allow you to convert from sound to image, but you can do this using a spectral analyser. The one I like is called Sonic Visualiser (http://www.sonicvisualiser.org/).

If the sound has an image encoded in the frequency space as a function of time you should be able to see the image in the output.

I hope that helps.

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