2004.05.10 22:29 "Re: [Tiff] Tiff questions", by Bob Friesenhahn

I am exploring using TIFF support for my image server that also supports FlashPIX. The general idea is that the images are very large, and people want to zoom in and out, so I am trying (pyramidal) multiple levels of downsampled versions of the same image, all stored as jpeg-compressed tiles.

You might consider using the "Pyramid" TIFF scheme supported by ImageMagick/GraphicsMagick ("PTIF" format). This scheme is a bit FlashPIX-like.

The strategy is to store multiple resolutions (different scaled sizes) of the image as frames of a multi-frame TIFF. Each frame is stored in tiled TIFF format. This allows the resolution to be quickly selected, and then a region may be efficiently extracted by reading the associated TIFF tiles.

To prepare the image, ImageMagick/GraphicsMagick simply successively reduces the image size and saves the result as a frame until the image size reaches a minimum threshold.

Bob

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Bob Friesenhahn
bfriesen@simple.dallas.tx.us
http://www.simplesystems.org/users/bfriesen