Research And Design Of High-speed Spike-based Image Sensor

Complementary Metal Oxide Semiconductor(CMOS)image sensor has many advantages,such as simple structure,high integration,low cost,fast readout circuit and so on.It has become the mainstream of image sensor development.With the demand of high-speed target tracking in military,medical and other fields,the theory of high-speed CMOS image sensor is gradually established.High-speed image sensor based on traditional Active Pixel Sensor(APS)has higher frame frequency,larger data volume and power consumption,which seriously restricts its further development.Considering that the Digital Pixel Sensor(DPS)converts light intensity into digital spikes with data compression capability,a high-speed spike-based image sensor is proposed in this paper to compress huge amount of data and enhance the frame frequency under the same bandwidth.In this paper,a pixel structure which combines the high-speed scanning sequence format with the method of using interspike time interval to represent the light intensity information is designed.Through converting the light intensity into spikes,the amounts of data are greatly compressed.With the high-speed scanning format,the information can be output rapidly.Based on the system architecture,the simulation verification and layout of pixel,bias circuit and row driver circuits are completed in this paper.In addition,the non-uniformity caused by spatial noise is analyzed.To suppress the influence of non-uniformity on the sensor,calibration algorithms multiplied by the measurement coefficient matrixes are proposed.The high-speed spike-based image sensor is fabricated in 0.11?m process.The test results show that the sensitivity of this sensor is 14.8 DN/(lux.s)by using the Digital Number(DN)during 1s under 1lux as the index of sensitivity.The signal-to-noise ratio is 42.5dB.The dynamic range of the sensor is 70 dB when the voltage of reset transistor is 3.3V and the reference voltage is 1.593 V.The speed test results show that the image sensor can capture the turntable information of 3000r/min.The results of non-uniformity-suppressed show that,based on spike frequency method,the standard deviation of the image decreases from 18.4792 to 0.5683 by using the calibration algorithm when the uniform light intensity is 500 lux.