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Old 04-19-2012, 11:41 PM   #105
geekmaster
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AHA! EUREKA! (whatever) -- Clipping boundary values to limits DOES work, except you replace all values below 16 with 16 (not 0), and you replace all values above 48 with 48 (not 64). It all makes sense now. Any, I want to add sliders to my dithermatron (controlled by touch or 5-way pad) to adjust brightness, contrast, gamma, and high and low clipping pedestals in real-time, while it is running the animation.

Here is my 16-48 clipped dither table:
PHP Code:
    static int dt[64] = { 16,32,16,40,16,34,16,42,48,16,48,24,48,18,48,26,16,44,16,
    
36,16,46,16,38,48,28,48,20,48,30,48,22,16,35,16,45,16,33,16,41,48,19,48,27,48,
    
17,48,25,16,47,16,39,16,45,16,37,48,31,48,23,48,29,48,21 }; // dither table 
If you try this dither table in palpump, you will see that it works correctly now that the first 17 values are black, and the last 15 values are white. We could adjust those cutoff points at even row boundaries if we wanted to. Something similar to this should fit your needs as described in previous posts.

EDIT: Clipping the entire first row to all black really shows how BAD the ghosting is after individual black pixels are changed to white and then back to black again. The result is that pure black pixels only look dark gray. White on black background does not work acceptably for animation, IMHO. So we need to avoid black backgrounds when possible.

Because the electric field that controls pixels affects neighboring pixels, you really need to change large areas to solid white or solid black to do a proper "reset" on the pixels to restore their full contrast range. A full flash erase assures that there are no edge pixels that get partial electric field crossover at high contrast boundaries on the display.



Last edited by geekmaster; 04-19-2012 at 11:54 PM.
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