A few months ago, during a fit of spring cleaning, I decided to sell the two dozen or so posters I'd been carrying with me from apartment to apartment for the last eight years.
I posted a list on my Web site, and after a few minutes decided that prospective buyers should be able to see images of the posters (clearly, I don't like doing things the easy way). The question: how to scan the posters--some of them a good yard across--using a scanner with only an A4-sized maximum scanning area?
Solution: scan partial images of a poster--an easy enough task--and stitch them together in Photoshop--a tedious to aggravating task.
If only I had waited a few months! Then I would have had the option of using Enroute
's QuickStitch, an inexpensive and user-friendly package designed to create images by compositing several smaller pictures. A similar product, QuickStitch 360, composites images horizontally to create panoramas; there's even an option for creating 360-degree panoramas (images can be exported as QuickTime VR files).
Enroute is aiming QuickStitch at the camera-toting consumer--either digital camera owners who want to get a larger, higher-resolution image out of even a lower-end 640x480 model, or those who want to composite scanned prints from conventional film. According to Enroute, that includes the ability to use mathematical warping to compensate for differing camera tilts and fisheye lenses.
To put QuickStitch through its paces, I borrowed some photographs from a friend. During a hiking trip, he took four photos with the express intent of stitching them together to create one stunning panoramic vista. After a quick trip to the scanner I had four images, each under 550x400, eagerly waiting to be fused into a greater whole. Unfortunately, there wasn't that much overlap between each photo (Enroute recommends at least a 35% overlap), but I thought I'd see what would happen.
I'll say one thing for Enroute--they know how to design a good user interface. They've incorporated a wizard with the interface itself by dividing the window into three numbered sections, so that you can follow each step while seeing every setting you've selected. Very clean, very simple.
Then I discovered that QuickStitch doesn't like LZW-compressed TIFFs. (I've noticed this trend in quite a few consumer graphics programs, and it irritates me to no end. While the software publisher saves a few bucks by not licensing Unisys's LZW algorithm patent, those of us who store our images in the compact, lossless format have to keep converting our images before we work.) After converting them, I placed the images and clicked on the Stitch option. After waiting a few seconds, I got... well, what I got was a surprise. As expected, I didn't get a perfect image; what I did get was a composite that rearranged the order of my original images and blended their edges together (which makes me wonder: why ask me to place them in the correct order if it doesn't seem to care?). QuickStitch 360 did the same.
I tried a second time using QuickStitch 360, this time using the Overlap Images window (only available in this version) to more or less line the scans up by eye before stitching--sort of giving the program a running start. This time the results were impressively accurate, but the areas around two of the seams were noticeably darkened. Theoretically, this could be fixed in Photoshop, but it wasn't encouraging.
Sticking with QuickStitch 360, I scanned a panoramic picture I'd taken with a disposable camera and divided it into three overlapping pieces. When I put them into QuickStitch 360 and clicked on Stitch Panorama, it worked--excuse the pun--seamlessly. Ruefully, I thought that If I'd had QuickStitch 360 a few months ago, I could have saved a lot of time with my posters. Out of curiosity, I tried using QuickStitch with the same images. The only word I can use to describe the results is "psychedelic": each scan was bizarrely distorted, and not even remotely connected.
To make a long story short, I threw all kinds of tests at both programs: scanned photos and digital camera snapshots that connected horizontally, vertically, or both; 39 pictures taken from a tripod-mounted digital camera to form a 360-degree panorama; the cover of an issue of the Computer Paper
. Thinking back to my posters, I threw a few of those onto the scanner as well. Overlaps varied from minimal to excessive, and just about every combination of settings was tried.
The upshot: when the QuickStitch products work, they work spectacularly (though they often warp the image unnecessarily). However, you have to plan ahead by giving your images plenty of overlap--aim for 50% (not that this is a guarantee; I still got strange results on several occasions). Given the programs' tendency toward "fixing" perspective problems that don't necessarily exist, you'll also have to accept that your final image may look fine, but only if you never saw the original (hey, that tree didn't bend like that in the original!)
If you have a lot of images to put together, QuickStitch and QuickStitch 360 can save you some time, by cutting down on the number of pictures you'll have to put together manually. But I wouldn't recommend depending too much on them.