Research of noise reduction and nonuniformity correction for CMOS image sensor

Charge coupled devices (CCD) technology has been for a long time the technology of choice in high quality image sensing. CCDs use a special manufacturing process to create the ability to transport charge across the chip without distortion. This process leads to very high-quality sensors in terms of fidelity and light sensitivity. Drawbacks are high power consumption and no possible on-chip processing capabilities. With CMOS reduced feature size technology, it becomes possible to add on-chip control and processing units in order to obtain a fully integrated camera on a single chip. For these reasons, it has gained potential for use in many applications. CMOS image sensors(CIS) use traditional manufacturing processes to create the chip -- the same processes used to make most microprocessors. Based on this difference, CMOS sensors traditionally have lower quality, lower resolution and higher noise. For gaining high quality image, the analysis of the types and reasons of noise and noise reduction for CMOS image sensor are very important. Noise control technology to various noises is discussed in this paper. Methods of noise reduction for linear CMOS imagers and logarithmic CMOS imagers are different. An important factor limiting the performance of sensor arrays is the nonuniform response of detectors. Fixed pattern noise caused by the nonuniform response of the sensors gives the uncorrected images a white-noise-degraded appearance. Nonuniformity correction techniques are also developed and implemented to perform the necessary calibration for sensing applications in this paper. Noise reduction and nonuniformity correction are effective ways to gain high quality images for CMOS image sensor.