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pngread does not read 12bit gray images
From: |
de Almeida, Valmor F. |
Subject: |
pngread does not read 12bit gray images |
Date: |
Sat, 05 Jul 2008 13:41:04 -0400 |
Hello,
I am using imread() to read 12-bit png images. The result of
Y = imread("foo.png");
class(I);
is uint16. However the max and min values of Y are not correct. I
tracked the problem down to this section of pngread.cc in the
octave-forge package image-1.06
// For now, use 8-bit only
if (bit_depth == 16) {
png_set_strip_16(png_ptr);
}
Is there a simple fix for this so that I do get all gray values into the
matrix Y? The issue here is that after the 8-bit strip, the image loses
critical information; in particular contrast details that are important
for the image processing code I am writing.
Thanks,
--
Valmor
PS: Actually I started writing an experimental pngread() for reading
gray images with depths greater than 8 bits. Since this is something I
have not done before, I would appreciate any inputs.
- pngread does not read 12bit gray images,
de Almeida, Valmor F. <=
- Re: pngread does not read 12bit gray images, Søren Hauberg, 2008/07/06
- RE: pngread does not read 12bit gray images, de Almeida, Valmor F., 2008/07/11
- RE: pngread does not read 12bit gray images, Søren Hauberg, 2008/07/11
- Re: pngread does not read 12bit gray images, Bill Denney, 2008/07/11
- Re: pngread does not read 12bit gray images, Søren Hauberg, 2008/07/11
- RE: pngread does not read 12bit gray images, de Almeida, Valmor F., 2008/07/11
- Message not available
- Message not available
- Re: pngread does not read 12bit gray images, Bill Denney, 2008/07/14
- RE: pngread does not read 12bit gray images, de Almeida, Valmor F., 2008/07/16
- RE: pngread does not read 12bit gray images, John W. Eaton, 2008/07/16
- RE: pngread does not read 12bit gray images, Søren Hauberg, 2008/07/17