I did it! :)
I finally realized how get the image from the received data.
Perhaps, the explanation will turn chaotic, but I'll try to explain as
precisely as possible.
On buffer with 61440 bytes length stored an image 192x80. And that's very
interesting that the correct pixel is located in the lower four bits of
every fourth byte. Moreover, any fourth byte. For example:
I can save PGM image with max gray level 15 from 61440 buffer by four ways:

char buf[61440];

buf[0]&0x0F, buf[4]&0x0F, buf[8]&0x0F ...
buf[1]&0x0F, buf[5]&0x0F, buf[9]&0x0F ...
buf[2]&0x0F, buf[6]&0x0F, buf[10]&0x0F ...
buf[3]&0x0F, buf[7]&0x0F, buf[11]&0x0F ...

As a result, are four almost identical images, visual difference is almost
insignificant. On the images very clearly visible the fingerprint.
Although it seems to me to invert the colors, so it will be correct: the
black lines of the fingerprint on a white background. In the initial
buffer all the way around, the white lines on black background.

Now when understandable how to convert a raw buffer to the image, another
questions arises ... All eight images - a sequence of sweeping finger on
the working surface of the scanner. And now it is unclear how to combine
the eight images into one that contains a full fingerprint. And what
resolution get this picture as a result... And in which format should I
send data to the processing libfprint after final assembly of the image?

Thanks in advance!


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