ldr.PTDigiI


This is what we call a direct loader, i.e. immediately after clicking "Load" on main screen, the loader is active without before opening the file requester. It is laid out for the older version of the Printtechnik Video Digitizer, and yields a picture of 256x248 pixels first, with 16 true shades of gray. The data arrive in the C64 as 128 vertical stripes, and will be rectified and piled anew after the read-in process. The aspect ratio of the video pixels (i.e. the relation between the horizontal extent of a dot and its height) doesn't coincide to that of the C64's pixels. The image will be stretched by a factor of 1.25 from 256 to 320 picture elements, i.e. GoDot will compute 5 new pixels out of 4 original dots. Finally the loader will just cut off the 48 pixel rows exceeding the lower border of the screen, so that the standard size of 320x200 will be produced.

Unfortunately, color video cameras and recorders as a matter of principle do emit their color carrier signal besides the video information. For good results, it should be filtered off, e.g. by a digisplitter. A digisplitter is a device that only transports a distinct portion of color (red, green, or blue extract) to the computer. It would be pretty appropriate for digitizing pictures up to 4096 colors with GoDot. Without a digisplitter you need three color glass filters that only let tramsmit light of the appropriate wave length (see also ldr.4BitRGB). After all, pictures only turn out good when taken with black and white video cameras (they provide no color carrier signal).

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Arndt Dettke
god.ADettke@t-online.de

Copyright © 1998, A. Dettke, Last Updated - 1/17/98