I don't entirely agree with this. While all the original pixels in the image may remain, it can be useful for the image to remember it's own size. I use hugin to stitch together large electrical schematics from scans (which it does an incredible job of!) and I like to know the actual size of the page. I'd prefer that the image remembered this information rather than me needing to.
Fortunately, the resolution seems to be pretty simple. Imagemagick will change the reported image density (see this answer <https://askubuntu.com/a/1224220>). And if you look at the imagemagick documentation <http://www.imagemagick.org/script/command-line-options.php#density> it just changes this one attribute, it doesn't change any pixels (i.e., it basically performs the inverse of what hugin is doing here). The command would be something like: convert -units PixelsPerInch my_original_image.tif -density 300 my_new_image.tif Matt On Tuesday, May 13, 2014 at 3:06:07 AM UTC-7 panostar wrote: > There will always be a difference between the original image and the > stitched image owing to the interpolation process that has been used to > remap the image to and from the spherical stitching surface. There are > several interpolators to choose from and there can be quite big differences > between them, depending on the nature of the image. It would be worth > trying some of the alternatives. Needless to say, the dpi/ppi has no > effect whatever on the image quality. It merely determines the default > linear size of the image when printed, but this can in any case be > overridden by most print programs and so is of no consequence. > > John > > > On Tuesday, May 13, 2014 5:57:53 AM UTC+1, [email protected] wrote: >> >> I scanned an A2 sized electrical schematic with an A4 scanner in 12 >> pieces, and tried out Hugin to stitch them together. The result is very >> promising but there is one problem - the DPI has been changed from 300dpi >> to 150dpi resulting in a smaller image and some loss of quality. >> >> Of course I have read http://hugin.sourceforge.net/docs/manual/PPI.html >> but before anyone starts telling me how this does not affect image quality >> etc please view the attached files and see for yourself how the quality has >> been degraded. >> >> I did try changing the DPI setting of the file back to 300dpi using Gimp >> but this made no difference. >> >> How can I tell Hugin (or its processor program) NOT to change the >> resolution down to 150dpi and rather keep it at 300dpi? >> > -- A list of frequently asked questions is available at: http://wiki.panotools.org/Hugin_FAQ --- You received this message because you are subscribed to the Google Groups "hugin and other free panoramic software" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/hugin-ptx/722c914f-7306-48bd-a6be-263de556680en%40googlegroups.com.
