A smart image sensor with novel implementation of quad-tree scan

The quad-tree scan is realized by scanning nodes of a two-dimensional tree structure applied to the image. Only activated or effective pixels are scanned with quad-tree scan. We designed the image sensor using 0.6 /spl mu/m CMOS 3-metal 2-poly-Si process. A 32/spl times/32 pixel array and a quad-tree scan controller are integrated on a 4.5 mm/spl times/4.5 mm die. Each pixel has an A/D conversion circuit and a motion detection circuit in a 96 /spl mu/m/spl times/96 /spl mu/m area. The quad-tree scan controller works at 10 Mcycles/s with 10 mW power dissipation.