1

I'm using the Kinovea (last version) to do the Bike Fit, but i'm having some problems with motion blur.
I'm using a JVC miniDV video camera Hi8 and transferred the image to my laptop with firewire.
Bike fit in work with anatomical landmarks, so the less image blur at the moment pause the video, the better.
I tested also with a Sony HDR camera and yet the continued blurring.
Can anyone help me with this problem?

Thanks,


Rafael - Brazil.

2 (edited by Chas Tennis 2011-06-24 16:20:38)

I summarized some information on motion blur is a recent thread.   

Basic High Speed Video Camera Considerations & Cameras

The main thing for motion blur is the exposure time or shutter speed.   If the shutter speed cannot be manually controlled you probably have to live with whatever motion blur the camera AUTO exposure control produces under given conditions. 

I believe, but do not know, that some camera AUTO controls will adjust exposure by shortening the exposure time/shutter speed.  If you operate the camera in direct sunlight the exposure time/shutter speed may be much faster as adjusted by the camera's AUTO exposure electronics.   I don't know this but read that my Aiptek Action camera works in that way.  ? A characteristic of this would be minimum motion blur for videos in bright direct sunlight and increasing motion blur as light is reduced with a great deal of motion blur for indoor high speed videos. 

I am not familiar with the cameras that you mention. What is the shutter speed?  What settings can you adjust, lens aperture?, ISO?, etc. Do any have manual shutter speed control?   

If you must live with AUTO exposure control try shooting with each of your cameras in direct sunlight. If you can adjust aperture - use maximum aperture (lowest F/#), use highest ISO that you can set. See what the camera AUTO control can do for motion blur in direct sunlight.   Please let us know how you do if you experiment with your cameras.

I don't know your application but if it involves high speed video and you will have future use I would purchase a Casio camera with manual shutter speed control. Used models are F1, F20, F25. The FH 100 may no longer be manufactured (?) but some are still in stock.  I don't know of other high speed video cameras with manual control. I would like to hear of other cameras along with links that clearly state the shutter speed for high speed video operation.

3

Hi Chas.... Thanks for the information.
So.... I tried all the things you wrote but the blur continuos..... I talk with a friend off mine, he has the same kind of handycam but he uses another video editor program and he said that he doesn't see blurs on his videos!!! Do you thing that this blur can be from Kinovea??
See you....

Rafael

4 (edited by Chas Tennis 2011-07-31 17:41:47)

Thanks for letting us know your results.

Motion blur relates to the blur from motion in the video and to no other sources of blur.  These are often large blurs, directional smears of the image, that can be inches long.  Usually motion blur is a problem only with the higher speed athletic motions in a video.  The rest of the picture should be clear but the golf club, throwing arm, ball, etc., has considerable blur.  Is that what you have?

Tripod. Motion blur can also be produced if the camera is not held steady and moves while the shutter is open, that is, with a slow shutter and a hand held camera.   Use a tripod to eliminate the camera's contribution to motion blur.  Motion blur from an unsteady camera will be everywhere. It will always show the direction that the camera was moving when the shutter was open - all blurs sideways or up and down, etc.

Kinovea can't produce motion blur.  To check this point and any other viewer blur differences look at your video in another viewer with excellent stop action such as Quicktime.   That should show the motion blur in the video and any other blur differences.

Also, research the shutter specifications of your cameras in the users's manuals or on the internet.   

I have no understanding of video compression issues that might might relate to your cameras or even if that could be an issue.  My Casio FH100 camera can be set to produce videos for Youtube. I assume that those files would be compressed and probably not useable for some stop action purposes but I don't know.

Have your friend upload a video to Vimeo or other video website that does not compress_CORRECTION SEE BELOW_the video (not Youtube) and view it yourself.  If possible do some experiments with your friend under identical conditions.

Details on compression & non-compression as used by Vimeo are described in these FAQ-

http://vimeo.com/help/faq#compression

5

Also, maybe you can post a screen shot so we can see how severe it is, and guess the most probable cause.