Phase Transfer Function Of Wavefront Coding System And Applications In The Design Of Phase Mask

As a computational imaging technique, the Wavefront Coding combine optical system with the image process to extend the depth of field. Comparing the traditional optical system, Wavefront Coding technique has incomparable advantages. However, its two-step imaging character does not comply with the original optical system info. In allusion to the imaging features and optimization theory of the Wavefront Coding, research on phase transfer function and the design of pupil-phase mask in the Wavefront Coding system is executed in this paper. It is hoped to perfect theory system and to lay the foundation for the wider application of the Wavefront Coding technique.In this paper, we propose an analytical PTF model of wavefront-coding systems with odd-symmetric quadratic phase mask and analyze the character of defocus PTF form quantitatively. Through comparing three types of phase plate, we analyse the imaging characteristic change that is caused by defocus difference of the phase transfer function.We present a parameters optimization method based on Matlab-CodeⅤ interface. The method that combine with the meteyard function of point spread function is used to optimize the parameters of three pupil-phase masks in Wavefront Coding system. Then the compare of three pupil-phase masks is proposed, which consist of cubic, tangent, exponential phase masks. The results of defocus invariance and imaging recover validate the validity and accuracy of the method.In allusion to the characteristic of SNR in the image restoration, we introduce the simple model of spectral SNR and the constraints based on SNR. At last we design the Wavefront Coding optical system of double Gauss lens, which combine the evaluation function of the PTF’s invariance. The final design results are given by image restoration technique, which validates the research and method above.