Le Van Nhu, Chen Shouqian, Fan Zhigang, Pham Nghia Minh
Appl Opt. 2016 Feb 10;55(5):1067-71. doi: 10.1364/AO.55.001067.
We propose the use of two asymmetrical phase masks combined with the subtracted imaging method to enhance the signal-to-noise ratio in wavefront coding systems. This subtracted imaging technique is similar to the variable pinhole diameter in confocal microscopy. Two different phase modulations of same phase masks are employed to promote the magnitude of the optical transfer function (OTF). The ratio factor is used to control the phase variation between two phase masks. The noise of decoded images is suppressed owing to the higher magnitude of the OTF than the wavefront coding systems with a phase mask. A tangent phase mask as an example is used to demonstrate our concept. Simulated results show that the performance promotion controls noise amplification of decoded images while maintaining a depth-of-field extension.
我们提出使用两个非对称相位掩模结合相减成像方法，以提高波前编码系统中的信噪比。这种相减成像技术类似于共聚焦显微镜中的可变针孔直径。采用相同相位掩模的两种不同相位调制来提高光学传递函数（OTF）的幅度。比率因子用于控制两个相位掩模之间的相位变化。由于OTF的幅度高于具有相位掩模的波前编码系统，解码图像的噪声得到抑制。以切线相位掩模为例来演示我们的概念。模拟结果表明，性能提升在保持景深扩展的同时控制了解码图像的噪声放大。
