Calibration means time taken by the sensor to measure max. value
255 for each channel which is also known as white reference calibration.
Based on this time I will read all the objects so that I my accuracy will increase.

The sensor gives 0/p in form of pulses
Max o/p freq(red)=24khz(peak wavelength=635nm)
Max o/p freq(green)=19.2khz(peak wavelength=524nm)
Max o/p freq(blue)=21.6khz(peak wavelength=470nm)

I am using TAOS TCS230.