D Vision Works D Joiner is a stitching program that’s used to assemble multiple rows of overlapping photographs into very wide-angle views. It’s useful for obtaining ultra-wide angle views from standard cameras, or to capture a complete spherical view for interactive location tours. Images can be exported for print or interactive panoramic viewers, or as Java applets for Web pages.
The new program is an extension of the familiar panoramic-stitching principle, but able to handle extra rows to provide the up-down as well as left-right directions. D Joiner uses a similar approach to the now defunct Enroute PowerStitch, where the user identifies several matching points in each pair of adjacent images, then the program distorts and blends them together seamlessly. This is more easily controllable than the £560 RealViz Stitcher 3.0, where you drag, rotate and scale adjacent images into visual alignment before blending.
Unlike PowerStitch, which only allowed four points per pair, D Joiner allows unlimited points, so you can add more for difficult matches, though there’s an increased danger of points being rejected if the program can’t find a solution.
As with any stitching program, you get the best results by putting the big effort in at the camera stage. Ideally, you need a tripod with a purpose-built panoramic head, but these are expensive. As D Joiner is tolerant of misalignments, hand-holding the camera is feasible, though some subjects won’t quite join accurately and you’ll get ghosting.
The process uses a lot of images, so it’s a good idea to use a digital camera to save scanning. Typically you can capture a complete sphere with four rows of eight images, using a 28mm lens or equivalent. File names should include numbers to show their order.
D Joiner has an easily learned user interface.
To start a new project you identify the image files to import, select the number of columns and rows, choose the horizontal and vertical orders, then they’re loaded and displayed in the correct positions. You can add or delete images later if needed.
Next, you double click to open each image pair, and create links by clicking on matching points in both images. This has to be done between all pairs in each vertical and horizontal direction. With at least four links per pair, an 8-x-4 set needs 204 links (408 clicks) to be entered with reasonable accuracy, which takes time. There are zoom and pan buttons to aid visual positioning. After each pair is set up, you can test-blend and navigate around in low res. The current screen view can also be test-rendered in full resolution.
With everything joined and tested satisfactorily, you can export the image in full resolution (you can’t interpolate up or down). For printable images or third-party viewers (such as QuickTime VR) you’ve a choice of projections: cube, cylinder, flat or sphere. Each can be saved as JPEG, BMP or TIFF format.
The fifth option, Java, writes an interactive zoomable applet placed in an HTML page whose code can be pasted into any Web site. D Vision Works is also planning to release code for a Shockwave viewer.
If you need accurate, high-resolution images to cover very wide angles of view, D Joiner gives excellent results at a reasonable price.