How can i convert 2D image coordinates into 3D world coordinates using kinect?

Hi everybody, What i want to do is detect a checkerboard pattern using kinect rgb camera and detectCheckerboardPoints() function and convert the 2D image coordinates into 3D world coordinates, distance from kinect sensor is most important for me. I am using imaq adaptor and supportpackage for kinect on Matlab R2014a with Windows 7 64 bit. 1) How can the conversion be achieved? I tried using the depth to cloud function but the depth values are not correct? 2) I also read about the conversion using Kinect's raw depth data but how can i access this data using Matlab? 3) What does the uint16 values returned by the Kinect mean? Are those the distance in mm already?

I would appreciate any help.

Bella

Answer 1

[Stalin Samuel]

http://www.timzaman.com/?p=501

[Bella]

Unfortunately i cannot access this website i am always getting a database error. But i found out some things on my own: 1) the uint16 values of the depth image are indeed the distances in mm 2) i can access the depths for the detected checkerboard points 3) Conversion from depth to world coordinates can be achieved using a depth to point cloud function. But i also encountered some issues: 1) When i access the depth data i need to switch x and y pixel values to get the correct depth values, where does this come from? 2) from the conversion of the depth image to the point cloud the y and z values seem to be correct but the x value is not? Any suggestions on those problems? Thanks in advance, Bella