RealViz Stitcher is a variation on the panorama program that lets you join rows of images in the up–down direction as well as the more familiar left–right. Stitcher 3.0 takes this ability as far as it can go and allows fully spherical images (360-x-360 degrees) to be created. When viewed on a computer screen, the result is a normal-looking navigable image that can be steered in any direction, looking left-&-right and up-&-down, to give the impression of standing in one spot and moving your head in all directions.
Cubic projection (spherical) images can be output in QuickTime VR format for viewing in QuickTime 5. Other spherical output options are for Java, VRML and Shockwave viewers. You can still stitch normal left-right panoramas or multi-row ‘quilts’ and output them as printable strips or interactive formats.
Stitcher 3.0 introduces a Mac OS option. Previous versions were confined to Windows NT/2000, which limited their appeal in the creative market. Mac OS 9 is supported now, with the promise of a free upgrade to the OS X version due in Q3 of 2001.
The user interface for both Mac and Windows versions is identical, and practically unchanged from v1.5 (reviewed in Digit #31): you import a sequence of overlapping scanned images or digital photographs into the image strip window, where you can arrange them in rough order, then drag them one by one into the stitching window. Once there, you blend the images together one by one, using position, scale and rotation tools to align the overlaps as closely as possible before hitting the Escape key, which blends them seamlessly. As you work, you can select the Adjust All Images option, which attempts to correct for the lens type and gives the correct perspective – even so, joins aren’t always perfect.
It’s a fairly lengthy business, especially for multi-row spherical sets, as the manual alignment can be tricky. It depends on the accuracy of the original photographs – you can just about get away with handholding the camera, but ideally you should use
a tripod with a special panoramic head to rotate the camera around the optical centre (nodal point) of its lens. A Kaidan KiWi+ head costs about £200 for horizontal panoramas. There’s a new spherical adaptor bracket for this, though it’s overpriced at £280.
If you’re creating 360-degree or spherical panoramas, there’s a menu that joins up the final images to form a complete circle. When all images are stitched, you can also equalize them, which attempts to correct for differences in exposure density. This isn’t perfect, so you should use identical exposures when shooting, or adjust at the scanning stage. Finally, you render the image with a choice of projections, file formats, and resolution. Rendering is a pretty lengthy business even on a decently fast Windows PC or Power Mac G4, especially if you’re working in high resolution for print.
Stitcher 3’s spherical ability is an alternative to
the specialized Ipix system, which stitches two back-to-back hemispherical images shot with an expensive fisheye lens. Stitcher costs more, but uses conventional camera lenses – and can create much higher resolutions as well as printable projections. Watch
out too for British developer D Vision Works, which claims its forthcoming D Joiner will be easier to use.