On 6 Dec 2005 at 6:17, Shel Belinkoff wrote: > How does the fact that Bob combined three smaller-sized JPEGs to make the > 6.5mb panorama effect the picture. Essentially he was printing three 2.2mb > quality JPEGs, just all together, or is my reasoning flawed? And what does > stitching together three JPEG files do to the information contained in those > files?
Interesting question. Well your logic isn't too bad it's just that there are some parameters missing from the equation that we can only guess. Assuming the images overlapped by 50% then the maximum print area could only be 2x not 3x assuming better than ideal. Of course the overlap could be as little as 10% but we don't know at this point. When images are stitched they are transformed to conform to the type of projection required. In these transformations data is lost at the top and bottom of the frame so generally a stitched image needs to be cropped top and bottom in order to remove these transform anomalies, so the overall image will end up becoming slightly narrower. A side effect of a small overlap is the need to crop the edges to a greater extent. Also of course the image may have been cropped further to optimise the composition. Of course there are probably other factors but you get the idea. The composite file hasn't likely one pixel where it was in the original file after all each image has been geometrically transformed to integrate with the adjacent image and then the areas that overlap have been subjected to blending. It might all sound a little impure but the results are often stunning. Cheers, Rob Studdert HURSTVILLE AUSTRALIA Tel +61-2-9554-4110 UTC(GMT) +10 Hours [EMAIL PROTECTED] http://members.ozemail.com.au/~distudio/publications/ Pentax user since 1986, PDMLer since 1998
