Motion Analysis, Slow Motion Cameras and Video Analysis Software

motion analysis, slow motion cameras, biomechanics motion capture

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Camcorder Requirements

An important word about camcorders: With recent camcorder innovations such as DVD and DVR units there has been a lot of confusion and misconceptions with respect to using them for motion analysis. People mistakenly think that because these are the latest units to hit the market that they must be the best. That's simply not true when it comes to motion analysis. These new units are fine for shooting video of junior's birthday party but they don't work for high-speed motion analysis where you want to capture a full 60 to 1200 frames-per-second (fps) and do accurate slow motion/freeze frame analysis.

Here are the camcorder facts you will need if you are going to do serious motion analysis: The only type of camcorder that is suitable for this purpose is a mini-DV unit. The advantage of these units for motion analysis is that they are the only ones that produce low compression digital video (AVI format) transmitted over a Firewire connection. This is essential for good motion analysis. New style DVD and DVR camcorders do not have Firewire connections and they compress the video (called MPEG format) to a point where you lose frame rate and picture quality at the frame level. Mini-DV units produce a full 60 fps and provide the best video thereby retaining full picture quality right down to the individual frame level.

Mini-DV camcorders produce the best video quality. Below is a comparison of a mini-DV (AVI) video on the left and a DVR (MPEG) video (on the right). Notice how all the areas of the AVI video are clear including the bat and ball while the MPEG video on the right is not as crisp. Notice that the fast motion of the bat and ball are blurred in the MPEG video.

Faster shutter speeds produce clearer videos. Below is a comparison of a higher shutter speed (1/2000) with a lower shutter speed (1/500). Notice in the high speed video that the bat and ball are "frozen" and sharp while, in the lower speed video, the bat and ball are blurry. The higher the shutter speed of the camera, the less blurring will occur for fast-moving objects.

High quality, high speed cameras are better for low-light conditions. Below is another comparison of a high quality GL2 camcorder and a standard ZR camcorder. The GL2 is capable of working at very high shutter speeds (up to 1/15,000) in low light conditions. Notice that, even though the GL2 is operating at a much higher shutter speed, the video is much brighter than even a slow shutter speed on a ZR camcorder. This can be very important for doing motion analysis indoors.

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email: salesinfo@sports-motion.com
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Sports Motion, Inc.
Offices located in California