三次位相板编码系统的频率信噪比分析

The Design of a Photographic Objective Using Cubic Phase Plate

建立了一个基于新型光学/数字成像系统(三次位相板编码系统-CPP系统)的信噪比模型.该模型主要考虑了读出噪音及散粒噪音两种探测器噪音,同时加入光学系统调制传递函数(Modulation Transfer Function,MTF)的影响,考虑不同空间频率下噪音对信号的影响,推导出频率信噪比模型.利用该模型对一个光学/数字成像系统进行信噪比分析,结果表明,利用该模型进行分析后此光学系统可达到的理论焦深扩展范围为5个波长.

The analysis tool, frequency signal-to-noise model, using in cubic phase plate （CPP） coding system is proposed. This model considers short noise and readout noise coming from CCD detector. According to perceived signal-to-noise theory, this model also considers the infection of modulate transfer function （MTF） which can realize the signal to noise ratio in different spatial frequencies. This SNR model can give an explicit analysis of CPP system and gives dependable references in CPP system design process. Using this model,the CPP system analyzed here can get 5 waves depth of focus in theory. It is proved that the model can work well.