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Re: pngread does not read 12bit gray images
From: |
Bengt-Arne Fjellner |
Subject: |
Re: pngread does not read 12bit gray images |
Date: |
Thu, 10 Jul 2008 19:23:30 +0200 |
User-agent: |
Microsoft-Entourage/12.11.0.080522 |
On 2008-07-05 7:41 PM, "de Almeida, Valmor F." <address@hidden> wrote:
>
> 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
I'm working on one to:
Download and try:
http://pinus.tt.ltu.se/~baf/pngread.cc
The test for endianness of the machine should be done during compilation but
I haven't figured out how.
And if it seems to work just include it in the distro.
- Re: pngread does not read 12bit gray images, (continued)
- 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
- Re: pngread does not read 12bit gray images, Bill Denney, 2008/07/17
- Re: pngread does not read 12bit gray images, Søren Hauberg, 2008/07/20
- RE: pngread does not read 12bit gray images, de Almeida, Valmor F., 2008/07/17
Re: pngread does not read 12bit gray images,
Bengt-Arne Fjellner <=