Monday, 14 November 2011

How to Digitise a throwing video

To digitise a video first you need a copy of either the trial version or full version of MaxTRAQ. Once this is done, open up a video file of a recorded calibration, make sure that the video is formatted in .avi form.
Using the scaling tool found under the tools tab, set the dimensions to 1meter/100 centimeters and then left click on both ends of the ruler to plot out a 1 meter/100 centimeter scale. If sound is activated on your computer you should be notified that your clicking has been confirmed by an audible 'beep'. If this action is completed successfully MaxTRAQ will automatically map out a checkered line with your plotted scale.
When finished, save your file as a MaxTraq template file (.mqt) and save it under a suitable file name.
Open this template file that you just saved (you may need to change the file type by clicking on the drop down arrow next to the file name) and MaxTRAQ will automatically ask you to open up another video (.avi) file. This is so that the video will be analysed using the calibrations you had set up using the template. Try opening the .avi video of the throwing video from the sagital plane.
Once this file is open, look under the time frame and deselect the T1 button, this is to see the whole video. Play the video until the point of release and pause at this frame, once at the frame go back 10 more frames using the arrow keys and keep this as a standardised reference point for later.
On the right hand side is a button labeled 'Digitise', click this button and then click on 'Auto-track'. This is found on the bottom-right corner of the screen. From here, click on the ball (you may need to zoom in to be more accurate) and maxtraq should automatically move forward one frame for every click, once again an audible 'beep' should be heard for every click made. Do this for 20 frames so that you have digitised data for both 10 frames before the release point and 10 frames after the release point.
Once completed, save as an ASCII file (.mqa) under a sensible file name i.e 'subject01_10m_eyeheight_01.mqa'. This file can be opened into excel where your X and Y coordinate values would have been automatically plotted. Put this data into a graph to see a curve of your data.
To make the curve smoother and to get rid of 'noise', digitise your data two more times, (so that you have a total of 3 sets of data), plot out an average of the data you have collected and the curve should be smoother and with less 'noise'.


  1. Excellent summary - good job, you'll find this a handy reference!

    A couple of minor things:
    1. Blogger doesn't cope well with text copied and pasted from things like Word. There's a lot of excessive formatting that gets carried over in the HTML. To tidy the formatting, either copy/paste from Word to Notepad, then to the blog, or type directly into the blog editor. This will just keep things tidy.

    2. Tag this post with your name and a couple of other relevant labels.

    For your next post, you should show some data! You should be able to take snapshots of frames from within MaxTraq, and you can save Excel graphs out as pictures.

  2. Do you have information about MaxTRAQ?????? studies?? please send me everything you have!

  3. HELLO! triying to use this software but its kinda hustle.. can i sen you some work you do for me at a fee?