Design of a variable resolution CMOS image sensor for a smart security system

Recently, CMOS Image Sensor (CIS) is now widely used in the field of security system. Normally, in an emergency state, a security system must record a picture in a high resolution mode. On the contrary, in a normal state without any events or accidents, it can take a picture in a low resolution mode. In this paper, a variable resolution CIS is described to implement a smart security system. A variable resolution CIS chip has been fabricated with a Samsung 0.13µm CMOS technology and it satisfied a QVGA resolution (320×240) with a pitch of 5.0 µm and a 4-Tr active-pixel sensor structure. The measured frame rate is 60 frame/s with a power consumption of 9.8mW at 2.8V(Analog)/1.5 V(Digital) power supply. When the variable resolution technique is adopted, the power consumption is about 2.7mW at the low resolution mode. Further, the chip area is about 19mm2.