I spent the best part of a day trying to create a lens profile for my trusty Canon PowerShot S90. In theory, it should be a rather straightforward thing to do. The Creating lens distortion models with Hugin’s lens calibrator article provides easy-to-follow instructions on how to create a lens distortion model.
Creating a lens distortion model with Hugin Lens Calibrator
I used a single RAW file to generate a simple model (see the screenshot above). I then added the following lens profile to the /usr/share/lensfun/compact-canon.xml file:
<model>Canon PowerShot S90</model>
<distortion model="ptlens" focal="6" a="0.01463" b="-0.07992" c="0.00461" />
So far, so good. digiKam seems to pick the added lens profile, but the Auto-Correction tool (Enhance → Lens → Auto-correction) produces a rather strange result:
“Auto-correcting” distortion in digiKam
I can’t figure out what I’m doing wrong, so if you have a suggestion, feel free to chime in.
Being a do-it-all kind of application, digiKam is suited not only for performing the mundane tasks of organizing and editing photos. The application also offers a specialized tools for more advanced operations: from blending bracketed photos to stitching panoramas. The latter functionality in digiKam is implemented as a Kipi plugin which relies on Hugin, a set of powerful tools for processing photos and stitching them into panorama images. The plugin wraps Hugin features into a user-friendly interface which dramatically simplifies the process of turning multiple photos into a panorama.
Obviously, to make use of digiKam’s panorama stitching capabilities, you have to install Hugin software on your system. Hugin is available in the software repositories of many mainstream Linux distributions, so you can install it using your distro’s package manager. On Debian and Ubuntu, this can be done by running the apt-get install hugin command as root. To install Hugin on Windows, grab the installer from the project’s website.
Stitching a panorama with Panorama Tool
Stitching panoramas in digiKam is a pretty straightforward process. Select the photos you want to stitch, and choose the Tools → Stitch images into a panorama command. This opens the Panorama Tool which guides you through the process of generating a panorama which consists of a few relatively simple steps. Each step lets you specify several settings, like the output format (JPEG or TIFF) and the ability to detect moving skies. You can also enable the horizon leveling and automatic projecting and crop options. To view brief descriptions of the available options and settings, hover the mouse over them. Once the Panorama Tool has finished stitching images, it prompts you to save the project file. Using this file, you can reprocess the photos in Hugin, if needed.