It is always desirable to lower the total noise without affecting the signal. This can be done by
reducing the dark current noise . Therefore special opto-CMOS processes with low dark current
should be used. Especially in automotive applications where the temperature can be up to 125°C ,
dark-current-optimized CMOS processes are essential for satisfactory performance because dark
current doubles with ever y 8°C. Improvements are also achieved by low amplifier- and reset-noise
on-chip and low system-noise, as well as decreasing background illumination noise. However,
since background illumination is an environmental parameter and not a system parameter, it is
difficult to decrease the background illumination in an observed scene. The number of photons
reaching the sensor can be reduced though. This is done by proper band pass filtering of the
in coming light.