Software development industry analysis by Larry O'Brien, the former editor of Software Development and Computer Language
Tuesday, August 22, 2006

My friend Fabian Gonzalez is producing some great images with high dynamic range (HDR) photography:

This is a technique that attempts to reproduce the incredible range of light-to-dark that our vision system integrates. After taking 3 photos (over-, under-, and correctly- exposed) of the same subject (in this case, managing to freeze the thinking / sad (?) man in the lower left) a program sees how each pixel changes in reaction to the light. From those 3 points, a curve is created and the pixel's "real" brightness is extrapolated (in other words, every pixel in every exposure is assigned one of just 256 values, but by seeing how the pixels shift between those bins depending on the exposure, you can determine many more than 256 absolute brightness levels).

Then, to create an image on a low-dynamic range device (like a screen or even film, apparently), you create a new set of curves to map the floating-point HDR pixels back into just 256 bins (per color channel). This step is where the "darkroom artistry" comes in; colors can be popped dramatically (see Fabian's shot inside the Metreon) but here Fabian's dialed things back, really capturing the feel of a warm San Francisco evening (if that's not an oxymoron).

I've tried to do HDR with my horrible, laggy, jiggly pocket digital camera, but have yet to produce an even moderately decent photo. Oh yeah, and I'm just not much of a photographer, either.

Tuesday, August 22, 2006 8:48:38 AM (Hawaiian Standard Time, UTC-10:00) |  Disqus link  | #
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