Tuesday, February 26, 2008

Panorama Stitching

Stitching is the term that is used for taking 2 or more images of a scene that is too large for one frame, then assembling them into one larger image. There is a lot of math involved in smoothing out once straight lines, and combining them into the natural curves found in natural viewing.

Panorama stitching programs can cost a lot of money, but HP offers Panorama Stitching as one of the tools in a free Photo Suite.

Above is the view from my south-facing balcony. It was stitched from 14 stills. Each still was 1920 x 1080 (pixels) (the same as one frame of High-Definition video).

According to Photoshop's Image Size, which I used to size his DOWN to 1800px wide for posting (click the image above to see a larger view), the re-sized photo is 25" wide at 72dpi -- but the full-sized Panorama photo was 110" wide (!)

This view is from my south-facing balcony, overlooking the 78 freeway that divides Carlsbad from Oceanside. Just to give you an idea of how to mentally straighten this out, the olive-green "railing" on the balcony that comes at the viewer at the left of the photo is the same 15' board (straight) as the one at the right end. This is almost a 180-degree view from east to went (l to r). Across the freeway on the right is a driving range where golfers hit their golf balls across a long, flat green onto a hill with targets marking how far their shot would calculate to if the hill did not stop the trajectory.
Tips for shooting stills for panoramas:
1. Lock the exposure, so that each shot will match the others. Auto exposure will adjust each differently. I made an exposure measurement in the middle section, then locked it and shot them all in sequence, left to right
2. After you shoot each shot, as you re-frame, make sure there is 1/3 -1/2 of the next frame filled with that portion of the scene you just shot. (1/2 is better) The more redundancy of information from shot to shot the better.

Load them into the HP Panorama Stitcher in order (it also allows you to re-order them, if you goof up) and click OKAY, and in a matter of seconds, it does the matching and the math and finishes off a large panorama.

Panorama software is built into a free set of tools made by HP
Mac versions (Photosmart Studio)
PC (look here)

No comments: