Background

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Before you start to record any videos, you'll need to evaluate scene's background. Background is the picture of only static (not moving) objects in the capture area. That means all actors and props they'll manipulate with during an action should be removed from the capture area for the course of background evaluation. Background is embedded into video files and is later used by iPi Mocap Studio to easily detect moving objects. Also, background is employed for compressing videos with the background subtraction method.

Usually background should be evaluated only once during a recording session. However, any time the environment gets significant changes, you need to reevaluate background. Examples of such changes include changing lighting conditions, introducing new or moving existing static objects within the cameras' field of view. Also, you will need to reevaluate background each time after you went back to Setup or Cameras stage, because changing the settings invalidates currently evaluated background.

Before starting evaluation, you can set its duration. In general, the longer duration, the better evaluated background. Though, default duration of 5 seconds is sufficient for the most situations. Less values can be set for testing purposes, when you frequently pass through Setup stage, trying out different settings.

Often there is situation when computer with iPi Recorder is located in some camera's field of view. So to evaluate background, you need to go away from computer, but being away, you cannot start the evaluation process. In that case, you can set delay for evaluation to start, so after pressing the EVALUATE button, you have enough time to leave capture area. After you've started delayed evaluation, count delay + duration seconds, and then you can safely return to computer.