pin Pinhole Image
pin is a pinhole image which allows the determination of the camera axis of rotation. It is one of several calibration images which are taken daily at each site. During the measurement a mask with a line of eight pinholes in it is placed in the light path. An image of the line of pinholes is taken at eight different camera rotation positions: 0°, 45°, 90°, 135°, 180°, 225°, 270°, 315°. This forms a pinwheel pattern, the center of which is the location of the camera rotation axis. The location of the camera rotation axis is determined during the VMICAL processing stage and is needed to rotate the wlm and nbc calibration images accurately.
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