Friday Video: Cool video tricks with the Apple iPhone 4’s CMOS camera and the rolling-shutter effect

Normally, a CMOS image sensor’s rolling “jello” shutter is a liability. Pan the camera too quickly and vertical straight lines become curved. That’s because there’s a time delay between the capture of one line of video and the next, and the next. The captured video frame is actually a time-staggered series of line images assembled into a frame. Normally, it doesn’t look good. But take an Apple iPhone 4, drop it sideways into a guitar so it’s shooting video of the strings with each string cutting across every scan line, then rotate the captured video 90 degrees and bingo: very cool video.

What you get is something that looks like a stroboscopic capture of the moving strings but that’s not what it is. It’s a time-staggered capture of string position instead of a quick snapshot of the entire string. It looks like one thing but it’s really another. Whatever it is, it looks really, really cool. Take a look:


About sleibson2

EDA360 Evangelist and Marketing Director at Cadence Design Systems (blog at
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