title: What is the difference between Binning and sub-sampling in Image Signal Processing?
body: <p>As I know, there are some functions in the CMOS Image Sensor ISP (Image Signal Processor).
   Specifically, I'd like to know the difference between binning and sub-sampling. I think these purpose is same to reduce image size.
  However, I'm not sure why these functions exist?
  What is their purpose?</p>