Analysis and modeling of quantization error in spike-frequency-based image sensor

Abstract A comprehensive analysis of the quantization error in spike-frequency-based image sensor is presented. The image sensor generates different frequency spikes under various light. Images can be reconstructed from spikes by counting the spike number in an integration period, however, this method will generate quantization error. Firstly, the quantization errors introduced by nonlinearity, comparator operation delay and synchronous reading mechanism, are studied. Subsequently, a previous designed spike-frequency-based image sensor with a 400(H) × 250(V) pixel array is tested, and the test results match well with the model results. When the illumination increases from 100 lx to 600 lx, the quantization error increases from −2.5% to 8% at the conditions that reset voltage is 3.3 V, reference voltage is 2.2 V, reading period is 25 μs and the integral period is 10 ms. In addition, under the conditions of illumination is 300 lx, reading period is 25 μs and integration period is 20 ms, the minimum quantization error (6.5%) can be obtained by selecting reset voltage is 2.9 V, reference voltage is 2.32 V. Thus, the results can serve design or usage guide for suppressing the quantization error of the spike-frequency-based image sensor.