[sane-devel] Sane backend for an intraoral X ray camera

[Mayuresh]

On Thu, Dec 31, 2020 at 10:47:02PM +0530, Mayuresh wrote:
> This scenario of converting raw data to an image must be very common in
> sane. Wonder if I could get some suggestions. If a python package (other
> than PIL for above issue) can do it, it will be better as the driver
> itself is in python. But even other alternatives will do

In the meantime I used libpng. It supports 16 bit depth. But the results
aren't yet correct - it's not looking like a normal X ray. May be I am
missing something about the image format.

I am keeping a sample image if anyone could try and reconstruct here:
http://mayuresh.sdfeu.org/img.dat.gz

Note the parameters:

width = 1168
height = 1562
depth = 16

It's little endian or big endian is unclear, both ways it is producing
results.

interlace is true or false is not clear, pypng did not show any difference
when interlace in its png encoder was true vs false.

It may require color inversion, which could be done either after
reconstructing image or during.

Here is some code using pypng:

# Please set flnm suitably
import struct
with open(flnm,'rb') as fp: buf = [ 65535 - v[0] for v in struct.iter_unpack('>H',fp.read()) ]

width = 1168
height = 1562
depth = 16
arr = [ buf[i:i+width] for r in range(height) for i in [r*width] ]

import png
with open('see.png','wb') as fp:
    png.Writer(
        width = width,
        height = height,
        greyscale = True,
        bitdepth = depth,
        ).write(fp,arr)