问题
Here's my Setup: Kinect mounted on an actuator for horizontal movement. Here's a short demo of what I am doing. http://www.youtube.com/watch?v=X1aSMvDQhDM
Here's my Scenario:
Please refer to above figure. Assume the distance between the center of the Actuator,'M', and the Center of the optic axis of Kinect, 'C', is 'dx'(millimeters), the depth information 'D'(millimeters) obtained from Kinect is relative to the optic axis. Since I now have a actuator mounted onto the Center of Kinect, the actual depth between object and Kinect is 'Z'.
X is the distance between optical axis and object, in pixels. Theta2 is the angle between optic axis and object. 'dy' can be ignored.
Here's my Problem. To obtain Z, I can simply use the distance equation in Figure 2. However I do not know the real world value of X in mm. If I have the angle between the object and optical axis 'theta2', I could use Dsin(theta2) to obtain X in mm. However theta2 is also unknown. Since if X (in mm) is know, I can get theta2, if theta2 is known, I can get X. So how should I obtain either the X value in mm or the angle between optic axis and Object P?
Here's what I've tried: Since I know the max field of view for Kinect is 57degrees, and the max horizontal resolution of Kinect is 640pixels, I can say that 1 degree for kinect covers 11.228 (640/57) pixels. However, through experiments I discover that this results in error of at least 2 degrees. I suspect its due to lens distortion on the Kinect. But I don't know how to compensate/normalize it.
Any ideas/helps are greatly appreciated.
来源：https://stackoverflow.com/questions/10226408/the-angle-between-an-object-and-kinects-optic-axis