On 15 Dez., 20:22, "T. Modes" <[email protected]> wrote: > Hugin is using the "official" Orientation tag (tag 0x0112) in the > "normal" EXIF data. This works for me. > But from your mail it seems that your raw converters destroy this > information.
I continued on my quest to create the optimal hugin input. What I ended up doing is to delete the CameraOrientation tag before raw processing (with digiKam 1.9.0) or use a raw processor which doesn't look at the CameraOrientation tag (dcraw, raw therapee, Canon DPP). I do the raw processing with the Orientation tag (which is a different tag!) set to horizontal, because otherwise all raw processors I know will rotate protrait data so they come out horizontal. After raw processing I set the Orientation tag back to what it would have been, had the camera been in autoratate mode. Now, finally, I have input fit for hugin: - the image data are now stored as per sensor geometry, which is always landscape, and the top row of the image data coinciding with the bottom edge of the sensor (because the image is upside down on the sensor, after all). Why is this important? Because now I can use just one single lens.ini file for all images with a particular lens, no matter which way I have rotated the camera, instead of having to use up to four different ones, one for each possible orientation. - the images do have rotation information in the Orientation tag, which is the tag hugin can exploit. This has the effect that when I generate my panorama with gen_pto, portrait images show up with roll of 90 or 270 degrees, respectively. This is also important, because otherwise I can't use one of the portrait images as anchor properly, and most of my panoramas are mainly in portrait. When loading such images into a new project in hugin, my hugin (Pre-Release 2011.5.0.71ffba4767f5) did not check the Orientation, but once the images were in the project I could go to the camera and lens tab, select all images and click on 'read EXIF data' - and lo and behold, now my orientation settings were there all right. Maybe the EXIF data of newly loaded images aren't read completely? Overhead shots will not show with an initial roll of 180, because my camera does not notice it's upside down but records 'horizontal' in this situation. I could manually set 'Orientation' to 180 degrees, but I don't usually shoot overhead, so I just ignore this possibility. While looking at these images which are good to feed to hugin, I had a good laugh at what various image viewers and image processing programs make of them. A few did what hugin does and displayed them rotated correctly, as per EXIF Orientation tag. Others ignored this tag and displayed the images in their 'native' orientation - the one which I took care to preserve in order to be able to use just one single lens.ini file on them. I can live with that, I don't look at the raw material that much and my file manager rotates properly. The funniest result was in digiKam, again: the image rotated 90CW showed up upside down and mirror-imaged! I'm sure they'll tell me I should try and upgrade to a more recent version if I posted a bug report... Things get even more confused when 'rotating' images in image processing software. Here, again, there are two possible ways to achieve a rotation: The software can just change the 'Orientation' tag, or it can change the memory layout of the image. Some image processing software gives you a choice what to do. The observable effect will, obviously, depend on which image viewer you use on the rotated images. I conclude that I have found a way of dealing with the problem, but it was a stony path (one of the reasons I have avoided the matter so long). There's plenty of possibilites to take a wrong turn here, and the unwary may easily end up with a false result. For hugin input data, my in-a-nutshell advice would be: - avoid rotation of the image data - easiest done by removing all orientation-related tags from the images before raw processing - before generating the pto, set the EXIF 'Orientation' tag to an appropriate value - generate the pro with pto_gen - or, after loading the images into hugin, read their EXIF data explicitly Kay -- You received this message because you are subscribed to the Google Groups "Hugin and other free panoramic software" group. A list of frequently asked questions is available at: http://wiki.panotools.org/Hugin_FAQ To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/hugin-ptx
