I saw Wii remote used for motion tracking in some videos online and it looks cool. I read its using IR tracking like TrackIR, what is the difference? Could the TrackIR be used for same type of project?
www.youtube.com/watch?v=Jd3-eiid-Uw
wii tracking?
Re: wii tracking?
Yes, you can use our OptiTrack SDK to write your own tracking applications for the TrackIR, see the download section of the OptiTrack page.
This is a good opportunity to compare them. There are two ways to measure the difference besides frame rate :
* sub-pixel and reporting resolution
* resolution per degree of field of view
sub-pixel and reporting resolution
Higher sub-pixel and reporting resolutions allow a device to track user movement more accurately and provide smoother response when used as an input device. Smaller sub-pixel numbers are better, and larger reporting resolutions are better.
The wiimote image sensor has a 128 pixel horizontal resolution with a horizontal (x axis) object/centroid reporting range of 1024. 1024 / 128 = 8 gradiations per pixel, so the sub-pixel reporting resolution is 1/8th of a pixel.
The TrackIR 4 sensor has a 355 pixel horizontal resolution. If TrackIR only had 1/8th of a pixel output resolution then its comparable horizontal reporting range would be : 355 * 8 = 2840. However, the TrackIR uses resolution doubling and other technology to provide greater accuracy, allowing it to resolve to 1/20th of a pixel.
This also means its comparable horizontal reporting range is : 355 * 20 = 7100
resolution per degree of field of view
Taking the above numbers, you can compare how much resolution each device has per degree of its field of view. This is how accurately each device is able to detect a tracked objects location, and how smooth the output will be as it moves. Larger numbers are better.
The wiimote has a ~45 degree horizontal field of view with a horizontal reporting range of 1024, so 1024 / 45 = 22.8
The TrackIR 4 has a ~45 degree horizontal field of view with a horizontal reporting range of 7100, so 7100 / 46 = 154.3
Results
This all means that as a tracking camera the Wiimote has a funcitonal resolution which is ~1/7th of the TrackIR 4 Pro's horizontally (and ~1/5th vertically).
Wii
Horizontal Pixels : 128 pixels
Horizontal Reporting Range : 1024
Sub-pixel reporting resolution : 1/8th pixel
Imager Frame Rate : 100 hz?
Reporting Frame Rate : 100 hz
Horizontal FOV : ~45 degrees
Horizontal resolution per-degree of FOV : 22.8
TrackIR 4-pro
Horizontal Pixels : 355 pixels
Horizontal Reporting Range : 7100
Sub-pixel reporting resolution : 1/20th pixel
Imager Frame Rate : 120 hz
Reporting Frame Rate : 120 hz
Horizontal FOV : ~46 degrees
Horizontal resolution per-degree of FOV : 154.3
*Update : added TrackIR 5*
TrackIR 5-pro
Horizontal Pixels : 640 pixels
Horizontal Reporting Range : 96000
Sub-pixel reporting resolution : 1/150th pixel
Imager Frame Rate : 120 hz
Reporting Frame Rate : 120 hz
Horizontal FOV : 51.7 degrees
Horizontal resolution per-degree of FOV : 1850
This is a good opportunity to compare them. There are two ways to measure the difference besides frame rate :
* sub-pixel and reporting resolution
* resolution per degree of field of view
sub-pixel and reporting resolution
Higher sub-pixel and reporting resolutions allow a device to track user movement more accurately and provide smoother response when used as an input device. Smaller sub-pixel numbers are better, and larger reporting resolutions are better.
The wiimote image sensor has a 128 pixel horizontal resolution with a horizontal (x axis) object/centroid reporting range of 1024. 1024 / 128 = 8 gradiations per pixel, so the sub-pixel reporting resolution is 1/8th of a pixel.
The TrackIR 4 sensor has a 355 pixel horizontal resolution. If TrackIR only had 1/8th of a pixel output resolution then its comparable horizontal reporting range would be : 355 * 8 = 2840. However, the TrackIR uses resolution doubling and other technology to provide greater accuracy, allowing it to resolve to 1/20th of a pixel.
This also means its comparable horizontal reporting range is : 355 * 20 = 7100
resolution per degree of field of view
Taking the above numbers, you can compare how much resolution each device has per degree of its field of view. This is how accurately each device is able to detect a tracked objects location, and how smooth the output will be as it moves. Larger numbers are better.
The wiimote has a ~45 degree horizontal field of view with a horizontal reporting range of 1024, so 1024 / 45 = 22.8
The TrackIR 4 has a ~45 degree horizontal field of view with a horizontal reporting range of 7100, so 7100 / 46 = 154.3
Results
This all means that as a tracking camera the Wiimote has a funcitonal resolution which is ~1/7th of the TrackIR 4 Pro's horizontally (and ~1/5th vertically).
Wii
Horizontal Pixels : 128 pixels
Horizontal Reporting Range : 1024
Sub-pixel reporting resolution : 1/8th pixel
Imager Frame Rate : 100 hz?
Reporting Frame Rate : 100 hz
Horizontal FOV : ~45 degrees
Horizontal resolution per-degree of FOV : 22.8
TrackIR 4-pro
Horizontal Pixels : 355 pixels
Horizontal Reporting Range : 7100
Sub-pixel reporting resolution : 1/20th pixel
Imager Frame Rate : 120 hz
Reporting Frame Rate : 120 hz
Horizontal FOV : ~46 degrees
Horizontal resolution per-degree of FOV : 154.3
*Update : added TrackIR 5*
TrackIR 5-pro
Horizontal Pixels : 640 pixels
Horizontal Reporting Range : 96000
Sub-pixel reporting resolution : 1/150th pixel
Imager Frame Rate : 120 hz
Reporting Frame Rate : 120 hz
Horizontal FOV : 51.7 degrees
Horizontal resolution per-degree of FOV : 1850