PETS2000 Camera Calibration
<A ID="pgfId-999337"></A> PETS2000 Camera Calibration Here is a calibration for of the camera for the test and training sequences. FocalLength f=1360 ImageCentre (u,v) = (384, 288) Homogeneous Transform T = 0.77900 -0.18953 0.59769 0.00000 -0.62703 -0.23676 0.74215 0.00000 0.00084 -0.95290 -0.30327 0.00000 -3479.05000 -849.37500 33783.70000 1.00000
The transformation takes a coordinated frame with the x-y plane as the ground plane and the Z axis vertical to the camera frame with nodal point at the origin, the z axis along the camera axis and the image plane aligned with the x-y plane. To convert to raster coordinates you need to scale by the focal length and add the ImageCentre. Note real world measurements are in millimeters and image measurements are in pixels. So let x be a point in the coordinate frame of the ground plane. Then that point in the coordinate frame of the camera is x T . The image of the point in raster coordinates is then given by (f( x T ) x /( x T ) z + u, f( x T ) y /( x T ) z + v) For example consider the point at the origin of the ground plane coordinates x = (0,0,0,1). Then x T = (-3479.05, -849.375, 33783.7) and image of the point in raster coordinates is given by (1360 x -3479.05 / 33783.7 + 384, 1360 x -849.375 / 33783.7 + 288) = (-140.0 + 384, -34.2 + 288) = (244, 253.8) Similarly a point 1 meter above the ground plane origin x = (0, 0, 1000, 1) would be (-3479.05 + 0.84, -849.375 - 952.9, 33783.7 - 303.27) = (-3478.21, -1802.275, 33480.43). The image of the point is then given by (1360 x - 3478.21/ 33480.43 + 384, 1360 x -1802.275 / 33480.43 + 288) = (-141.3 + 384, -73.2 + 288) = (242.7, 214.8)