New Method for Analysis of image sensor to produce and evaluate the image

In this paper, a new method for evaluating CMOS image sensors based on computer modeling and analysis is introduced. Image sensors are composed of different parts, each of which has a specific effect on image quality. Circuits of image sensors can be evaluated and analyzed using circuit simulators or theoretically, but these methods cannot help to produce the final image. In order to produce the image and evaluate it, it is necessary that the image sensor chip is made and the image produced by the chip is practically tested in the laboratory. Using the proposed method, it is possible to model any block of the sensor and examine the effect of that block on the image without making a chip. In this paper, the effect of source-follower as a pixel readout circuit on the final image has been investigated. The simulation results showed that the source-follower circuit with a 20% attenuation and a 1.15% non-linearity effect on the pixel signal can cause a significant error in the generated image. The related circuits are designed using 0.18µm CMOS technology and simulated by CADENCE software with SPECTRE simulator and also MATLAB software is used to model it.