Camera

In contrast to our previous work, we used only the simple robots head-mounted RGB camera to collect the measurements. The nominal intrinsic paramterers of the camera are:

The calibrateted parameters are:

Name	Symbol	Unit	Nominal Values	Calibrated Values
Resolution	/	Pixel	(640, 480)	/
Frustum	/	Degree	(57, 43)	/
Focal Length	\( f_\mathrm{C} \)	Pixel	523.1053	518.1601
Camera Center	\( c_\mathrm{C} \)	Pixel	(323.9319, 244.0806)	(323.8356, 249.8531)
Radial Distortion	\( \xi_\mathrm{C} \)	Pixel	0.023217	0.001327

The transformation from the last frame of the head to the camera is known from a previous calibration by

\[\begin{align} \mathrm{old:}\,\,{}^{\mathrm{c}}T_0 = \begin{bmatrix} 0.021778 & 0.204164 & 0.999554 & 0.135092 \\\ 0.017923 & -0.999638 & 0.002003 & 0.000701 \\\ 0.999602 & 0.017479 & -0.022136 & 0.174262 \\\ 0 & 0 & 0 & 1 \end{bmatrix} \end{align}\]

The new calibrated frame is

\[\begin{align} \mathrm{new:}\,\,{}^{\mathrm{c}}T_0 = \begin{bmatrix} 0.027059 & -0.00143 & 0.999632 & 0.140637 \\\ 0.011088 & -0.99993 & -0.001738 & -0.000161 \\\ 0.999572 & 0.111314 & -0.027042 & 0.174157 \\\ 0 & 0 & 0 & 1 \end{bmatrix} \end{align}\]

Note that the camera is mounted vertical in the robots head.