The unique Codamotion technology arises from work started by David Mitchelson in the early 1970's at Loughborough University in the United Kingdom.
He set up and established the vision for Charnwood Dynamics, the parent company for all Codamotion systems:
"Codamotion is a supplier of motion capture equipment to the academic research, clinical and other related life science markets, with the goal of enhancing lives."
..and set out general technological goals for our systems that still remain with us today:
High spatial and temporal resolution and accuracy
(sub millimetre and >200Hz)
Automatic identification of markers
Real-time output of co-ordinate data with millisecond latency
Good ease of use
What We Did In The 1970s
At the time of the original development a number of possible techniques were evaluated. These included ultrasound, radar, inertial devices, and video cameras, all of which were rejected as not meeting one or more of the above criteria. So a long odyssey began to find a method that would.
By the mid 1970's, a method was developed using solid-state injection lasers as the markers and a hybrid analogue/digital optical mask as the detection device within the cameras. It was also at this time that the concept of three high-resolution uni-axial cameras mounted on a rigid frame was devised. This enabled the system to be pre-calibrated to allow calculation of the 3-D co-ordinates, without the need for the user to carry out on-site calibration.
The first system was developed as a research instrument within Loughborough University, United Kingdom and achieved resolutions of 1 part in 4000 at a 1KHz sampling rate. It was not a commercial system and it was felt it did not attain high enough spatial resolution.
What We Did In The 1980s
The next generation of the Codamotion system was developed within a commercial setting and used passive corner-cube retro-reflecting prisms as markers. The prisms were automatically identified by colour using revolving polygonal mirrors as scanning devices. Beams of light were swept across the field of view by the mirrors. When a marker was briefly illuminated by the transiting beam it reflected a pulse of light back via the same mirror. The returning light pulse was detected via a complex set of fibre-optics and photodiode Prism detectors.
Resolutions of better than 1 in 50,000 (approx 0.2mm) at 300Hz sampling rate were achieved with this version of the Codamotion system, a small number of which were produced commercially. While its spatio-temporal performance was far better than any other technique available at the time, it suffered from the limitation that only a maximum of 12 prism markers could be uniquely identified by colour.
What We Did In The 1990's
The power of embedded microprocessors made possible the next generation of the Codamotion system. This became all solid state, using a unique optical correlation technique to achieve resolutions of up to 1 in 100,000 at sampling rates up to 800Hz. The markers were changed to small infrared LED's allowing 56 markers to be tracked simultaneously.
Into the 21st Century
NASA's desire to put motion capture experiments into space led to the development of the CX1 sensor unit, in a 5kg that was only 800mm long, yet measured with the accuracy of passive systems that spread cameras widely apart on lab walls. Weight, portability and the fact that such sealed systems needed no on-site calibration made the CX1 the choice of researchers and clinicians around the world. It's reputation for reliability, accuracy and ease of use has never been questioned as the technology - now much refined - has continued to be at the centre of the world's best motion capture systems.
NASA never flew the original CX1s, because its space shuttle programme was cancelled following a crash, but the idea of putting motion capture systems into weightless 'space' conditions has recently been revived by the European Space Agency. They have, once again, turned to Codamotion technology to meet their needs.