a hairy heirloom

kw: family history, photography

A few years ago my father sent me this old horse blanket that had belonged to his grandmother. As a matter of family history, it is thrilling to have it. It is a tapestry woven from horse hair, as the best ones of the time were made, because it doesn't irritate the horse. The artistry is equally amazing.

To photograph it, I first laid it out on the driveway and took a picture from a ladder. That picture is very keystoned, however, and I wanted one that was more straight. I decided to take several pictures, shooting straight down, and try to find panorama stitching software, but nothing was available at a cost I was willing to pay.

Recently, the price became right for the stitcher that comes with Windows Live Photo Gallery: free. I am becoming quite a fan of this program, even besides its panorama tool. I used it for a few "straight line" panoramas, but I wondered how it handles multi-line image sets. This horse blanket was the perfect subject; the four shots I took have a large overlap with the center of the blanket. The stitcher worked quite well. The overlap error seen at top center and left middle are because of my missing the angle on one of the "vertical" shots. I may take the blanket out of mothballs someday and re-shoot.

The original for the stitched image is about 12 Mpx. It contains an amazing amount of detail. This crop shows the blanket stitches for one of the roses and the edging. (Note: The image you get by clicking the first pic is a 1Mpx reduction, while this one is being shown full size, 400x300.)

Handling larger images is showing up the deficiencies of my current computer. It takes about eight seconds for Irfanview to open the 12 Mpx image. I needed to see if this scales with image size, so I went to a nearby library and photographed the building in two ways. First, I took four images with the camera horizontally oriented, then eight with it set vertically. It took MLPG about five minutes to produce a panorama with the set of four, and ten minutes with the set of eight.

The latter panoramic image is nearly 50 Mpx, and takes almost a minute for Irfanview to open, even though the file is an 8 Mbyte JPEG. I noticed some time ago that a 7 Mbyte JPEG of a much smaller number of Mpx (10, I think), opened quite a bit quicker than that, so it is the uncorking large numbers of pixels that takes the time, not the reading of the bytes off the disk. Makes sense.

The upshot? I need more computer! I am waiting for Windows 7 to get out; then I'll get one. The XP/Vista/W7 saga is another story entirely. Suffice for now, I just don't want Vista.