In Bike Fit uses some anatomical points to observe the correct angulation of the cyclist on the bicycle. One of these anatomical points is the lateral malleolus of the ankle.
I'm trying to use the "Track Path" of Knovea to accompany the anatomical point during the pedal cycle, however, often even using low speed in the video, the point is lost and I can not use this feature.
Has anyone used this feature and have any tips to me?
2 2012-01-17 21:02:02 (edited by Chas Tennis 2012-01-17 21:08:10)
Your application may be favorable for the use of markers especially since you can view from the side and the markers probably would move in a plane. Is the bike moving or a stationary bike?
Thread with marker discussions:
http://www.kinovea.org/en/forum/viewtopic.php?id=404
My experiments with markers for tennis stroke analysis were brief. Kinovea tracked a brightly painted ping pong ball marker on my tennis racket until it got near a white line in the tennis court. It always lost track approaching the line.
I did not spend much time looking for improvements in the marker approach for tennis stroke analysis partly because tennis strokes are a complex 3D motion in a cluttered background. I believe that 2D motions such as peddling or running are more favorable to using simple markers with a single camera.
If you describe your experiment from the optical standpoint I'll see if I can give you some considerations for a marker approach.
Thank you for your feedback "Chas Tennis".
Here in my Studio I work with cyclists and they are placed on the roll of training.
I use circular spots as markers ..... black or white. I realized that with white markers is more difficult, however, still have complications with black markers.
Have you tried placing retro reflective tape on the foot and blocking other interfering specular reflections such as from chromed metal parts, painted surfaces, etc? Place the light source next to the camera lens and illuminate the retro-reflective tape on the foot. Or copy the illumination techniques used in 3D motion capture. Some discussion and references are in the marker thread.
Kinovea tracked the ping pong ball marker on my tennis racket well when the background was dark or featureless.
Thanks Chas... I never tried reflective markers.... I'll see what can I do here!!! Thanks again!
Rafael Vicentini- BRAZIL
Greetings. My experience is similar to yours. There is not sufficient contrasting in the image of the knee for Kinovea to use as a marker frame-by-frame.
I just posted an image and graph of my use of LED markers for road bike fit frontal knee tracking in Kinovea.
http://www.kinovea.org/en/forum/viewtopic.php?id=404
I had very low ambient indoor lighting for this experiment. I will follow up with higher ambient lighting to improve the digital camera performance.
I did not experiment extensively with retroreflective markers. My experience was the lighting required was distracting to the cyclist. It might be useful for outdoors, but I believe these LEDs might also work in sunlight.
As discussed in the other post, I use a CR2034 battery holder as the base for the LED markers.