Frequently Asked Questions

Software - Answers

What operation system can be used?
WINDOWS XP or WINDOWS 2000

Does the software package synchronize recording and/or playback of two or more cameras at once? SIMI Software claims to have capture software that allows operation of all cameras by pressing a single button for start and stop, but is the video actually synchronized to the same clock. These is possible for Simi Motion, Simi Twinner Pro, Simi MoStill.
All cameras are captured at the same time and the system knows the exact time difference between the cameras (frames/fields and the small offset between two cameras since they are not hardware-synchronized, and shutter-open time is not exactly identical). After capturing, you can cut the videos (all clips at the same time) to extract only the part of the video you are really interested in. The remaining small offset (less than 17 ms for NTSC) is used during 3D reconstruction.
The video images themselves are not synchronized better than ½ field (8.4 ms).
The video "clock"-signal is made by each camera. Two cameras will have a shift due to clock inaccuracies of max. 1ms.

Does your system support foot pressure distribution measurement?
Yes, plug-Ins for TekScan, Novel, Parotec or Medilogic in Simi Motion or Simi MoStill are available.

How are the cameras triggered to begin sampling? Is pre-trigger sampling available (i.e., camera samples to memory until triggered and then saves data from a period of time before sampling)?
The cameras are frame-synchronized, which means that you have according to frame 1 of camera one the next neighbored frame of camera 2. Digital camcorders can not be genlocked, but our software calculates the shift between those neighbored frames and knows the time when camera 2 should have taken a frame which would have been time-synchronized to camera 1. That information is integrated in the 3D calculation and increases the accuracy of the calculated data to an accuracy of 1ms.

Must the sampling rate be a multiple of the field rate (60 Hz)?
No, all diagrams and calculations are time-based (in seconds) not sample-based, so all data like video, force-platforms, pressure distribution etc. can have different frequencies.

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