I attached the Leap Motion device onto HTC Vive headset, and tested Leap Motion's default hand tracking features.
The assembled device is shown here:
The technology in Leap Motion camera is infrared detection, therefore many features (or bugs) can be easily explained by it.
There is something to notice:
- Leap Motion is acurate and quick when two hands are wide-open and not too close. (As seen in Fig.1 bellow).
- Leap Motion can also detect hidden fingers when hands face down, but it only happens when there is no intervene (hands not touch/close to each other, nothing hot/no one else intervene), preferably when hands are wide open before this state. (As seen in Fig.2 bellow).
- When two hands are too close or interlaced, Leap Motion may or may not detect each hand and each finger, depending on the previous gesture and moving speed. If both hand gesture were easy to detect and move slowly towards each other, then even if they are interlaced, Leap Motion can still detect each hand and each finger. Otherwise if the previous hand gestures are unclear or two hands move quickly towards each other, the detection would fail. (as seen in Fig.3 bellow)
- When one hand is above the other, overlapping occurs, Leap Motion may or may not detect each hand and each finger, depending on the moving speed. If both hands move quickly, so overlapping happens only in short time, Leap Motion may lose detection for a short period of time and re-rendering the hand tracking, so the color on the hand model would change, but the tracking remains. If both hands move slowly, so the beneath hand may be unseen or intervened by the above hand for several second, Leap Motion would lose detection of the beneath hand, and may even fail to re-render it after overlapping finished. (As seen in Fig.4 and Fig.5 bellow)
- The rendering time of all images are around 10 ms (about 90 fps), which is fast enough for a real-time, immersive experience.
- The FOV (Field of View) of Leap Motion is (claimed to be) 180° x 180°*, FOV of HTC Vive is 113° x 100°*, FOV of human vision is 174° x 135°*. So tracking image from Leap Motion is wide enough for human vision, and will be limited by FOV of HTC Vive.
More testing images: