Image processing can require a lot of computing power, especially with high-resolution cameras or those capable of high continuous shooting speeds. The Sony Alpha a900, for example, has twin BIONZ processors.
This diagram shows how the Sony BIONZ system works (apologies for the small text). In the first stage, the sensor captures the image as analog light values which are then converted into digital values by the sensor itself. Here, the sensor also applies a noise reduction process (on-chip noise reduction is becoming more popular). Next, the BIONZ processor takes over, applying a second noise reduction process and turning the data from the sensor into a RAW file or applying camera settings like white balance, sharpness, saturation and so on to produce a JPEG image. In the third stage, the image file is saved to the memory card.
The BIONZ hardware works closely with the sensor to produce the final image file. You can think of the sensor as the 'capture' device and the BIONZ chip as the 'processor'.
Other camera makers have their own brand names but the processes are similar. Canon, for example, uses 'DIGIC' processors, while Nikon calls its processing system 'Expeed'.
