LibTiff Mailing List
TIFF and LibTiff Mailing List Archive
February 2009
Previous Thread
Next Thread
Previous by Thread
Next by Thread
Previous by Date
Next by Date
Contact
The TIFF Mailing List Homepage
This list is run by Frank Warmerdam
Archive maintained by AWare Systems
Thread
2009.02.17 06:00 "Re: DNG question", by Gordon Wetzstein
Hey guys, thanks for the answers. I had a look at dcraw, which is a great tool, but I'm working on some de-mosaicking algorithms, so I need the CFA data. There is some sample code for a simple c DNG exporter (elphel_dng.c), which uses different TIFF directories to store the thumbnail and the raw data. Unfortunately, my DNG files only have a single TIFF directory when I open them. I can extract the RAW data with dcraw, but the code is somewhat cryptic, so I don't quite understand how to access it. Since I use the Adobe DNG converter to create the files from various different SLR cameras, I can just set the compression to none, so that shouldn't be a problem. I saw that Dave Coffin has a patch for libTIFF 3.8.2 on his website, but I'm using Windows XP and don't quite know how to apply that patch to my libTIFF. Maybe I'll give that another shot. I also had a look at the DNG SDK, but it seems huge I would like to keep my stuff as simple as possible. Thanks for your help. Gordon On Mon, Feb 16, 2009 at 8:53 PM, Chris Cox <ccox@adobe.com> wrote: > You might be better off using the DNG SDK instead of LibTIFF. > > Chris > > ________________________________________ > From: tiff-bounces@lists.maptools.org [tiff-bounces@lists.maptools.org] On > Behalf Of Gordon Wetzstein [gordon.wetzstein@gmail.com] > Sent: Monday, February 16, 2009 4:35 PM > To: tiff@lists.maptools.org > Subject: [Tiff] DNG question > > Sorry for another newbie question, but I'm trying to read DNG files with > libTIFF 3.8.2. > > I have converted my Nikon RAW files to DNG using the Adobe DNG converter. > dcraw can correctly read the files, so they should be fine. Unfortunately, I > cannot access the RAW data in the file from my program. > > If I just open the TIFF file and read the tags, I only access the > thumbnail, because the image size is smaller and I have an RGB image. I want > the RAW mosaic data, however. Calling 'TIFFReadDirectory' until it returns 0 > tells me that there is only one subfile in the TIFF, so no need to bother > trying to change the TIFF directory. > > I also tried to get a subimage with: > > uint16 numSubimages; > uint32 subimageOffset[256]; > TIFFGetField(tif, TIFFTAG_SUBIFD, &numSubimages, &subimageOffset ); > > numSubimages is always 1. Does that mean that there is one more subimage > that I can access via TIFFSetSubDirectory(tif, subimageOffset[0]) or does it > mean that there is only the thumbnail? If the latter is the case, how can I > access the RAW data? > > Any help is highly appreciated. > > Gordon > > >