2.6.1 Camera Calibration
The camera calibration process is usually done by using neutral gray patches in order to
calibrate the uniformity ofthe CCD sensor ofthe low-encl camera which contains only a
single CCD under the control capturing environment (Hong et a|., 2000). The single
CCD oflow-end camera has to respond to the red. green and blue light at the same time
by clevoting one half of the elements to green sensitivity and one quarter each to red and
blue, emulating human vision. which is most sensitive to the green portion.Therefore.
the neutral gray patches which have the value ofR=G==B is needed to check the CCD of
the camera. ln the other word, ifthe CCIJ ofthe camera works accurately or uniformly,
then the camera ROB value will have R=G=B. However, there are other factors that can
affect the RGB value which are the uniformity ofthe target, the uniformity of the light
source and tlte quantization errors. Nevertheless. these factors are under controlled in
this research.