proj-imim:
Some questions
Daniel Maurer 2001-Apr-30 20:31:08
Hi,
i just want to ask a few questions which always apear during my production process.
1. With my old camera setup (Sigma 8mm AF EX, self made pano head, portrait mode) i came to an average FOV of 183.5 degree which is quite reasonable for this lense. With this setup i had my fixed starting values for FoV, a, b, c and used this as template in PtGui. So I only had to set about 5 controll points per seame and i very fast came to a good stitch. Values for FoV, a, b, c always were in the range of the template file (FOV= 182- 185, a=negative value between 0.2-0.4, b=positive value between -0.3 and 0.6, c= negative value between -0.3 - -0.6). Straight lines appeared straight (which is most significant I think).
With my new setup (new tripod head, Manfrotto QuickTimeVR) the camera is set to portrait mode and I cannot use my old starting values. Instead I made a new "master file" (For this i use an indoor photo with a lot of vertical lines, set a lot of controll points and try to get a good stitch) which led me to new starting values. The values for a,b,c are also a=negative, b=positive, c=negativ, but much smaller (down under 0.0) but the value for FOV is reduced to 173-175 degree. The result of the stitch looks even better than with the old setup. Stitching is not more work now but what i wonder about is the field of view. Has someone made the same experiences and can give me an explanation?
2. During scanning i set one image optimization on one image and keep this adjustments on the other two images. In theory this would mean that all three images are of the same brightness and color. After stitching i always have a lot of brightness and color mismatch in my resulting PSD File. Have you got the same experiences? I have uploaded a typical series of images on www.360visits.de/panotools.htm i would be interested in what way your first stitch looks like.
3. Something about the topic scans from PhotoCDs. I have tried the differnt CCD scanners from Fuji which are the front end of the Frontier Minilab series. I cannot advice scans from this machines for stitching because of the automatic color correction. This will lead you to severe problems when you try blending the seams. The same problem will be on PhotoCD scans.
But for those of you also shooting on medium format i can advice this very much, scans are cheap and of a very good quality. (and you should take a look at: scanning a 6x9" negative to 40 MB takes about 8 seconds )
Bye
Daniel Maurer