Assembling Panoramic Photos: A Designer's Notebook

2.5. Stage 5

2.5.1. The assembly

Before launching ImageAssembler I made sure that the pictures were all the same size in pixels. Their format wasn't important since the program can assemble pictures in JPEG, TIFF, BMP, PICT, and other formats at the same time.

In ImageAssembler, images are assembled in two stages. First you launch the Lens Wizard, which needs at least two contiguous pictures from the panorama so it can calculate the parameters of the shot: camera angle, focal length, optical distortion, etc. Open a blank stitching project and pull the pictures into it, place a series of flags at the same places in two adjacent photos, and run a trial stitch by clicking a button on the toolbar. ImageAssembler calculates the parameters; you'll save these parameters and use them later when you stitch all the pictures together.

I opened the five pictures of the series and arranged them in order from left to right, including the two photos that I had earlier corrected in Photoshop. You can place the flags automatically or manually. I've had great success in placing them by hand, so I took the manual route. I then selected the Lens Wizard parameter file that had just been calculated, chose the projection type (in this case, spherical), and started the stitch.

In the completed assembly, the perspective was corrected: the straight vertical lines no longer converged. ImageAssembler's sophisticated algorithms do this by subtly warping the pictures, as if they'd been projected onto a sphere. ...