Sunday, June 28, 2009

Data logging and graphical representations

In our proposal, we talked specifically about the need for maintaining a record of student performance as they carry our various training excercises, games or other activities with the WiiCane. Depending on the applications to which our system is put, we need to capture movement along the course in formats that will be of interest and of use to trainers and teachers. So, we need to begin considering how this will be accomplished in our system, and who will be responsibile for its implementation.

We looked at the output from RoboCane, a project carried out by Bruce Blasch, et. al. as a starting place for thinking about this.
Robocane was a computer simulator for cane travel. Researchers could enter parameters like cane length and traveler dimensions, and
the system produced a graphical representation of theoretical traveler matching those characteristics walking a straight course was produced. The purpose of this software was to allow the developers see the impact of making changes to various paramters on efficiency and safety for the theoretical traveler. It was expected that this information could be interpreted in the context of training actual students, to help the traveler optimize his or her performance by adjusting individual attributes of his or her technique.

Graphical record of cane travel from RoboCane
from: Blasch, Weiner & Welsh, Foundations of Orientation and Mobility, second edition

I am hoping that our system will be capable of generating graphical output like the sketch in this post. This shows a record of cane movement over a course: slanted lines show the top view of the cane at each time increment, and the line that represents the widest sweep (coinciding with the observed cane tap event) is darkened to make it stand out and to emphasize the period of the classic sine wave pattern produced during perfect execution of two-point touch technique. A side view will help illustrate the movement of the cane in the z (vertical) direction; a different sine wave will show the movement of the cane as the tip reaches its apex (height above the floor) at mid-swing.

It should be relatively straightforward to generate a visualization of wiiCane data like I am describing here. I am hoping that we can set up a process to do this as part of the software running on the computer that is being used to communictate with the wii. It would be helpful if a visual display on the computer showed the diagram being produced in real time. In the Optotrak system that we used in the verification experiment at WMU, an image can be produced that shows the movement of the cane in all three axes, however this is shown as three separate lines, and the there is no real-time display of the data. I will ask Rob to post an image of the data that Optotrak produced when we ran some subjects last week.

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