SR300 available hand detecting range

[LPaul2]

Hi,

When the hand is close and in front of the camera, around 200 mm ~ 650 mm,

the hand tracking module could detect hands RealSense::Hand::HandData::QueryNumberOfHands(),

then once the detected hand move further, around 900 mm,

the hand tracking module could not detect that hand anymore, this result looks normally.

But we found that, if the hand is away from the camera,

e.g., initial position of hands maybe at 1000 mm, and keep moving closer to the camera,

the hand cannot be detected until the depth (distance between the center of palm and camera) is around 650 mm.

the result is not expected as the spec mentioned (available range 200 mm ~ 850 mm), was there anything wrong with our test?

Thanks in advance.

Sincerely,

[MartyG]

Your results sound consistent with what I have experienced with the implementation of RealSense in the Unity game creation engine. Please bear in mind the following factors:

(1) When you move the hand very close to the camera, the camera will lose detection and tracking will stall, because the camera can no longer identify the individual hand joints at that range.

(2) When moving your hand back away from the camera, ensure that you are keeping the hand relatively level with the height of the camera lens. It is very easy to unconsciously drop the hand down when pulling it back and drop it out of the camera's view, also causing the tracking to stall.

For very close range detection, the cruder Blob Tracking method works better than Hand Tracking, as it simply recognizes the palm as a flat-ish mass rather than looking for individual joints. The trade-off is that Blob Tracking is poor at long-distance detection, requiring the hand to be very close to the camera.