Taming raw images with ImageMagick: A virtual workaround for Ubuntu 9.04
Published on 5th May 2009 Estimated Reading Time: 3 minutesWhile using a command line tool like ImageMagick for image processing may sound a really counter-intuitive thing to do, there's no need to do everything on a case by case interactive basis. Image resizing and format conversion come to mind here. Helper programs are used behind the scenes too, with Ghostscript being used to create Postscript files, for example.
The subject of helper programs brings me to an issue that has hampered me recently. While I am aware that there are tools like F-Spot available, I am also wont to use a combination of shell scripting (BASH & KSH), Perl and ImageMagick for organising my digital photos. My preference for using Raw camera files (DNG & CRW) means that ImageMagick cannot access these without a little helper. In the case of Ubuntu, it's UFRaw. However, Jaunty Jackalope appears to have seen UFRaw updated to a version that is incompatible with the included version of ImageMagick (6.4.5 as opposed to 3.5.2 at the time of writing). The result is that the command issued by ImageMagick to UFRaw - issue the command man ufraw-batch to see the details - is not accepted by the included version of the latter, 0.15 if you're interested. It appears that an older release of UFRaw accepted the output device ppm16 (16-bit PPM files) but this should now be specified as ppm for the output device and 16 for the output depth. In a nutshell, where the parameter output-type did the lot, you now need both output-type and output-depth.
While I thought of decoupling things by using UFRaw to create 16-bit PPM files for processing by ImageMagick, it was to no avail. The identify command wouldn't return the date on which the image was taken. Though I even changed the type to 8-bit JPEG's with added EXIF information, no progress was made. In the end, a mad plan came to mind: creating a VirtualBox VM running Debian. The logic was that if Debian deserves its reputation for solidity, dependencies like ImageMagick and UFRaw shouldn't be broken, and I wasn't wrong. To make it work well, I needed to see if I could get Guest Additions installed on Debian. Out of the box, the supported kernel version must be at least 2.6.27 and Debian's is 2.6.26, so additional work was on the cards. First, GCC, Make and the correct kernel header files need to be installed. Once those are in place, the installation works smoothly and a restart sets the goodies in motion. To make the necessary shared folder to be available, a command like the following was executed:
mount -t vboxfs [Shared Folder name] [mount point]
Once that deed was done and ImageMagick instated, the processing that I have been doing for new DSLR images was reinstated. Ironically, Debian's version of ImageMagick, 6.3.7, is even older than Ubuntu's, but it works and that's the main thing. Since there is an Ubuntu bug report for this on Launchpad, I hope that it gets fixed at some point in the near future. However, that may mean awaiting 9.10 or Karmic Koala, so I'm glad to have this workaround for now.