Zhenbo REN¹, Ping SU^2*, and Jianshe MA²

¹Department of Precision Instruments, Tsinghua University, Beijing 100084, China
²Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China

(Received August 5, 2013; Accepted September 23, 2013)

A hologram always contains redundancy. Its huge information content brings difficulties in the storage and transmission. In addition, when a computer-generated hologram (CGH) is reproduced, the zero-order diffraction spot which occupies most of energy reduces the contrast of reproduced image and disturbs the observation and recording. In this paper, discrete cosine transform (DCT) is used to compress the information content of a CGH and to eliminate the zero-order spot. Numerical simulation results showed that, DCT could effectively remove about 64.8% of the redundancy without affecting the quality of reconstruction. It also eliminated the zero-order spot and improved the contrast of reproduced image. Finally, the optical reconstruction results were shown. Numerical and optical experiments both proved that, the reconstructed image after compression almost did not lose any resolution that human eyes could perceive.

Key words: DCT, computer-generated holography, zero-order image, information content compression, image entropy

^*E-mail address: su.ping@mail.sz.tsinghua.edu.cn