Camera Synchronization in Logger Pro

Description

This is a step by step guide telling you how to synchronize video captured using LoggerPro to data also taken in the same program. Using this guide will help you have your data taken with detectors perfectly line up with data taken from movies.

Process

First you need to learn the offset between when the computer starts capturing video, and when LoggerPro starts taking data. We did this with a switch and battery connected to a voltage probe. Using the voltage sensor hooked up to LoggerPro, we could see the moment that the movie claims the button was pushed, and the moment LoggerPro did. After doing this many times, we learned that our camera, an old Canon Optura, has an offset of .67 seconds. Each camera will be different. Our Sony camera had an offset of .76 seconds. However, although each camera is different, the offset will allways be the same for that one particular camera, as long as you captured the video in LoggerPro.

To use this, first capture a video in LoggerPro that has both video, and some other type of data (for example, motion sensor or force sensor data). On the video that was imported, on the bottom right, there will be a button with two arrows pointing at a line. That is the synchronization button. Click that.

On the first line, select in the pull-down menu the data set you want the video to be linked to. Normally, for us, that is simply "latest". Then check the box for "Synchronize Video Analysis Data Set with Selected Data Set." Then enter the offset. In the box saying "Graph time" put zero. In the box titled "movie time" enter your offset (.67 for the Canon). If you plan on capturing more movies, select the box that says, "Use this Synchronization in Video Capture." That will make it so that all the videos from that moment on will have the offset pre-set. This setting should stay stored in the program every time you enter it. However, if data is used where this is a different offset, you will need to do all of these steps again from the begining.

Technical Details

Sony DCR-TRV120 hooked up with our iMac G5: offset of .76 s
Canon Optura (original model) hooked up with same iMac: offset of .67 s

Our Data||~ Camera
  1. of Trials
Minimum Offset (s)
Maximum Offset (s)
Mean Offset (s)
Std. Dev. (s)
Canon
24
.649
.692
0.672
.00967
Sony
9
.753
.776
0.76
.00758

Software


Primary Author and Contributors

  • Primary Author: Lars Schweidenback
  • Co-Author: Mike Harris