![]() So I'd like to reformulate the problem as finding raw images (think matrix of pixels) in a large file. If I can do this, I hope to find the content of the windows, at least partially. My idea was to rely on the fact that a row of pixels is similar to the next one. If I find a large enough number of lines of the same size, then I let the user fiddle around with an interactive tool and see if it decodes to something interesting.įor this, I would compute a kind of spectrogram. ![]() More precise a heatmap where the shade show how likely it is for the block of data # x to be part of an image of width y bytes, with x and y the axis of the spectrogram. Then I'd just have to look for horizontal lines in it. The problem I have right now is to find a method to compute that "kind of spectrogram" accurately and quickly. That means processing a few tens of MB per second.Īs an order of magnitude, I would like to be able to find images of width 2048 in RGBA (8192 bytes per row) in a 4GB file in a few minutes. I tried using FFT and autocorrelation, but they do not show the kind of accuracy I'm after.
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