I intend to make a gait recording (stride length). What is the better camera position (distance)? There are any minimum distance for recording?
2 2013-10-04 15:25:43 (edited by Chas Tennis 2013-10-04 19:33:38)
What video camera are you using? High speed video?
The most telephoto zoom lens setting will give less magnification variation across the frame. (Sometimes called a 'flatter field'). A wide angle zoom setting will give you more distortion across the video frame.
On the other hand, a wide angle zoom setting - the lens f-number 'speed' is 'faster' - will probably reduce motion blur if your camera uses automatic exposure control. Motion blur might not be an issue for your application because the gait velocities are not that high. ?
http://www.kinovea.org/en/forum/viewtop … 3059#p3059
Best to video in bright sunlight to minimize motion blur.
Recommend trying the most telephoto zoom setting for accuracy and see if the motion blur is OK.
- joan
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I concur on what Chas said regarding zoom and shutter speed if your camera support changing these parameters. If you are using a webcam or similar device, place it so that what you want to see fills most of the image.
If you plan on making measurements, another important aspect is the calibration of the space. To make accurate measurements you should either make sure the camera is perfectly perpendicular to the plane on which you make all your measurements, or use the perspective grid to map a physical rectangle and make the measurements on that plane.
I'll try to do a more in depth post to compare the errors that can be expected from both calibration methods.