Calibration

RGB Camera Calibration

Follow the directions here to calibrate the RGB Sensor. The package comes with a calibration file for the Kinect device we have at CCNY.

Depth Calibration

The Kinect's depth output appears to be linearly proportional to the inverse of the distance to the object. Depth calibration was determined experimentally, by measuring the reading of the center pixel in the depth image, and doing a regression on the data. The first attempts at calibration are presented here - more accurate calibration will be required in the future.

http://ros.org/images/wiki/kinect_node/kinect_calibration.png

The calibration results are available here:

Calibration (.ods)

Cross Calibration

Currently the 3D sensor is manually calibrated to match the calibrated RGB image data, future work needs to be done to correctly determine the calibration between the RGB and Depth cameras.

Automatic Calibration Tests

http://ros.org/images/wiki/kinect_node/calibration_irpaint.jpg Testing IR reflectivity various paints. Low angles of incidence provide some difference in reflected data, however the output power of the laser IR projector limits the usefulness of this approach. One thing that has not been tested is somehow attenuating the IR projector.

http://ros.org/images/wiki/kinect_node/calibration_holes.jpg This shows an attempt at using holes to produce a cross calibration

http://ros.org/images/wiki/kinect_node/calibration_cube3D.jpg An idea for a 3D calibration cube. The idea is to fit planes in the depth image and detect corners in the RGB image.

http://ros.org/images/wiki/kinect_node/calibration_victory.jpg A working calibration technique?

Wiki: kinect_node/Calibration (last edited 2011-05-26 19:29:40 by KenConley)