Saturation Compensation Circuit for Radiation Hardened CMOS Image Sensor

The objective of this project is to develope saturation compensation circuit and algorithm for real-time CMOS image sensor under radiation environments. Radiation hardened CMOS image sensor is an essential component in nuclear industry for various applications such as reactor maintenance, nuclear fuel displacement, and fuel examination. Moreover, in severe accident, the sensor can be used for monitoring reactor buildings by unmanned vehicles such as robots. In addition to nuclear field, the system is widely used in medical applications such as x-ray imaging, radiation therapy, and PET/CT. However, existing systems does not allow real-time data acquisition but process signal processing techniques after obtaining contaminated data induced by radiation. The developed algorithm was implemented in a circuit between CMOS image sensor pixels and ADC stage. With the circuit technique, compensated images can be immediately obtained in real time, while the software algorithm indispensability takes some time in comparison with the hardware approach. The developed algorithm makes the real-time data acquisition possible with compensated error pixels affected by radiation. After irradiation test, error pixels per frame were decreased from 15000 to under 100