INTERVIEW
Darbee Visual Presence
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way of processing the images, which turned out to be pretty simple. If you used the lens on one of the cameras to defocus the picture—say, on the right image—and then used the synthesizer to subtract the blurred image from the other sharp image, it works! It was the most amazing thing. Depending on what the cameras were looking at, especially natural scenes like trees, it was just miraculous. It would sometimes give you a depth effect that could be interpreted as a 3D image. It was a stunning effect and I thought it would be a wonderful thing to somehow bring to the world. However, the necessary digital processing to perform the needed convolutions for this goes up enormously fast, and for serial processors that’s almost a non-starter. For that, and
many other reasons, I just put it on the shelf as a curiosity and did other things like the universal remote control and some other companies that did machine-vision controls. How did your extensive experience help you start DarbeeVision?
derlying mathematics, and in the digital world everything was very stable. You could try things out and tweak different parameters and play with the convolutions. I quickly learned the dark side of this underlying defocusand-subtract algorithm—it can do bad things in an image just as easily as it can smuggle in the depth cues.
The first thing that I did was to recreate the analog video synthesizer as a digital program. It was about 500 times out of real-time, so it took many seconds to process a single frame. It was slow, but pretty! I was mostly downloading stereo frames that I could find on the Internet. I also created a few myself and that let me see afresh what the subjective effect looked like, which was glorious. I could also work in detail with the un-
Over the preceding decades, I studied a lot of math and digital signal processing and learned the background of what other people had done along these lines in computational imaging. One thing that I knew was that merely defocusing an image and subtracting it from itself wasn’t anything new. That was discovered by photographers early on and it’s called an unsharp mask. It is a very well-known highpassing edge enhancement filter. Visit www.eeweb.com
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