According to photography and recording means

The basic principle of digital camera is simply the conversion and transmission of photoelectric digital signals. That is to say, the optical signal is converted into current through the photosensitive element, and then the analog electrical signal is converted into digital signal, and the information obtained after special chip processing and filtering is restored to the dynamic picture we see. The photosensitive element of digital camera can convert light into charge, and the charge is converted into digital signal through analog-to-digital conversion chip. There are two main types: one is the widely used CCD (Charge Coupled Device); The other is CMOS (complementary metal oxide conductor) device.