Bi-directional phase compensation to accelerate conical hologram generation

Conical holography attracts the attention of researchers because of its ability to expand the field of view in the vertical direction. However, the integral in the vertical direction is needed compared to conventional cylindrical holography, leading to the slow speed of calculating a conical computer-generated hologram which requires to be improved. In this paper, a bi-directional phase compensation is proposed to accelerate conical hologram generation for the first time. In the proposed method, a sparse rows recording is used to record the diffraction field when one of every-three rows is calculated directly. And since the amplitudes of adjacent rows of the diffraction field are similar, a conical hologram can be generated by compensating a bi-directional phase difference to those adjacent ones from the rows by the sparse rows recording. The correctness and feasibility of our method are verified by the numerical simulation and compensation error analysis. And simulation results show that the calculating speed of our proposed method is three times faster than that of the conventional method with quality degradation of only 0.34 dB in PSNR. Therefore, the issue of slow calculating speed in conventional conical holography is addressed efficiently.