Using sensors for Arts, Sports and Science
My area of use with this technology has been with the creative arts and mixed media.
I have used motion capture to generate sound and visual data based on body movement.
Research suggests that more and more sports are adopting motion capture to improve research into optimal body/muscle performance as sports become more scientific.
One can single out a group of muscles and use the technology to create a graphical representation in 3D imaging software. This would allow better understanding of which muscles/tendons etc. are being used as the images can be slowed down and monitored frame by frame.
An early example of motion capture was produced by Eadweard James Muybridge (http://www.fandango.com/eadweardjamesmuybridge/biography/p188003). In the 1880s Muybridge produced over 100,000 images of animals in humans in motion. This influenced visual artists as well as the scientific and industrial fields in photography . It paved the way in which we work with motion capture today.
Systems I have used include Junxion by Steim (http://steim.org/product/junxion/), a software programme that allows various input sources to control MIDI (Musical Instrument Digital Interface) and OSC (Open Sound Control).
One particular input source is the Arduino (http://www.arduino.cc/), an open source electronics project platform that allows a plethora of sensors to be connected.
Surfing has a multitude of issues when capturing body movement. One obvious one being that the subjects arms and legs will be submerged in the water but in oscillations causing it to be difficult for a camera to capture accurately. The differences in the light refraction index in water and air causes distortions in the image.
A better way to capture motion would be to use sensors attached to the body such as EMG (Electromyography) electrodes. These are cheap sensors that pick up electrical activity of muscles.
A suitable system could be setup using the Arduino board to control software to plot a graph of muscle tension for example. One could also create a 3D model of a muscle group and use the electrical signals produce accurate 3D representations of the various muscle activity.
Other such sensors do similar things. The Bendmicro by Infusion Systems (http://infusionsystems.com/catalog/index.php) would allow you to observe elbow, wrist or knee movement for example. Whilst accelerometers, tilt sensors and gyroscopes could respond to larger area body movement (to monitor speed of arm movement penetrating water, for example).
Of course, having all of these electronics doesn't come without it's problems when using them in the water.
Suitable waterproof housing would be nesecary as well as creating a way of attaching sensors, wires and a microcontroller board to the subject without it being too obtrusive.
Another thought is if it data needs to be fed back to a computer in real time. Issues arise with wireless technology, though are overcome with much more expensive wireless communication systems available today.
Arduino produce a WiFi board, negating the need for cumbersome wires to be attached to the microcontroller (certainly not an option for someone surfing in the sea).
If the data is not needed in real time then the microcontroller can be simply connected to a data storage device on the body and uploaded into the necessary software back in the lab.
A final thought on the subject; with sensors becoming much more readily available and cheaper, as well as systems like the Raspberry Pi (which I haven't touched on here) being able to do a lot of these things in one unit, I can see many more sports taking motion capture seriously even at a semi professional level.
Our smart phones are increasingly becoming monitors of our health statistics, not to mention already having most of these motion sensors built into them allowing us to monitor running and cycling information for example.
We can already link a Bluetooth heartrate monitor, GPS monitor, so forth and so on, to a smart phones. I believe the next progression will be a surge in wireless sensors we can link to our smart phones and tablets to really dive deep into how our bodies are performing in sports as well as day to day tasks.
Ian McGinn
