Hi Corinna, could you tell me the image type you're passing into read_image? Regards, Christian On Thu, Nov 3, 2011 at 10:53 AM, Corinna Kinchin wrote:

Hello,

I'm using

       boost::gil::read_image(in, img, tiff_tag());

as part of a process to extract raw image data from a TIFF file, and it works beautifully for cmyka TIFF files containing either 5 x 8-bit channels, or 5 x 16-bit channels. But it seems using this technique mangles image data contained in a (photoshop generated) TIFF file which contains CMYK channels with both 8 and 16 bit depths (mixed).

Here is an extract from the ImageMagick 'identify -verbose' output on such a file:

 Depth: 8/16-bit

 Channel depth:  cyan: 16-bit  magenta: 16-bit  yellow: 16-bit  black: 8-bit  alpha: 8-bit

It seems that read_image treats the TIFF file as if it contains 5 x 8-bit channels (the TIFFTAG_BITSPERSAMPLE property and hence the _bits_per_sample info value for the TIFF file is set to 8), so the CMY channel image data isn't read in correctly ... at least that's my best guess.

Does anyone out there know whether boost::gil can be made to support 8/16bit TIFF files - eg if there's an extension (or hack ;) which could do the trick? Or any other options (eg other libraries) which could be worth investigation?

Many thanks for reading this far, and if you have any remotely relevent ideas it would be great to hear them ...

All the best,

Corinna ...

 Corinna Kinchin                 email: ckinchin@datazone.com  Datazone Ltd.                   Tel:   +353 64 66 28964  Palm Gate, Greenane,            Fax:   +353 64 66 28965  Killarney, Co. Kerry, Ireland   URL:   http://www.miramo.com

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