|Posted on Thursday, February 03, 2000 - 8:28 pm: |
Where the images overlap and are stitched together there is a shadow or dark vertical line from top to bottom of the image. Any suggestions on how to reduce this effect?
|Posted on Sunday, February 06, 2000 - 6:06 pm: |
Sometimes this is caused by brightness "fall-off"
in the corners of the imported images. The fall-off can be caused by vignetting or just by the nature of your lens design. In simple lenses, brightness falls-off by the fourth power of the cosine of the angle away from the center. Lens designs compensate for that fall-off, but sometimes the compensation is not completely successful.
The fall-off is generally more pronounced in the corners of the images and tends to show more with smaller overlaps. Overlaps approaching 50% don't really show the effect.
Elsewhere I recommend 20-40% overlap. If you suspect that your overlaps are darker because of brightness fall-off, it may help to increase the amount of overlap.