建立了基于电吸收调制器(EAM)的深度成像系统数值模型. 为定量描述时序误差对系统精度的影响推导了含尺度因子的测量误差公式, 分析了光调制器参数、系统噪声和时序误差对测量误差的影响. 结果表明, 无时序误差时, 测量值标准偏差与传感器阱中信号电子数的平方根成反比, 与阱中背景电子数和信号电子数之比的平方根成正比; 采用高调制速度和高消光比的EAM 可以提高系统精度; 随着时序偏移误差增加, 系统精度将迅速下降且难以通过增加传感器阱中信号电子数的方式提升; 如要求7 m 处单幅深度图像精度小于1 cm, 则需要传感器阱深大于等于300 Ke, 时序的偏移误差小于等于±200 ps.

A numerical model of electro-absorption-modulator (EAM)-based time-of-flight depth system is established. A formula with scale factor is deduced to quantify the contribution of timing-error to the accuracy of system. Measurement error is studied with parameters of EAM as well as background noise and timing-error. The results show that with no timing-error the standard deviation of measurements is inversely proportional to the square root of the number of signal electrons and is proportional to the square root of the ratio of the number of background electrons to the number of signal electrons. System accuracy improved by employing EAM with high speed modulation and higher extinction ratio. With skew error increasing, measurement error rises rapidly and is difficult to be reduced by increasing the number of signal electrons in the well of sensor. The well capacity of sensor must be larger than 300 Ke and the skew error of signal must be less than ±200 ps if the accuracy of 7 m single depth image is required less than 1 cm.