I made a final adjustment and test before I try to do something practical with it. The FEZ now controls the input threshold directly using analog out and I changed the switch that the Video Experimenter uses to a 4066 for software control. The FEZ checks the average frame value each time and adjusts the input threshold until it has a balanced view. I thought it would have to be more complicated but it seems to find a balance no matter how bright or dark the input.
The flicker is because it has to use the same buffer for input and output. It’s just for debugging anyway because the input isn’t normally seen.
There really isn’t much to it. I’ll post the code and more detail when I work out a couple application ideas. The ATmega chip is about maxed out just with the basic function so the possibilities get a lot less restrictive with the FEZ in control. It’s even possible now to capture multiple frames at different settings to have more detailed gray scale data instead of pure b&w.
Here’s a test that captures 150 frames at different levels then combines them into a gray scale image. There’s a lot of detail available considering it’s only 1 bit input. It’s only practical to 4 levels real time otherwise it’s like taking a photo from the 1800s.