Abstract
Phase-only spatial light modulators (SLMs) are widely used in holographic display applications, including holographic image projection (HIP). Most phase computer generated hologram (CGH) calculation algorithms have an iterative structure with a high computational load, and also are prone to speckle noise, as a result of the random phase terms applied on the desired images to mitigate the encoding noise. In this paper, we present a non-iterative algorithm, where simple Discrete Fourier Transform (DFT) relations are exploited to compute phase CGHs that exactly control half of the desired image samples (those on even - or odd - indexed rows - or columns) via a single Fast Fourier Transform (FFT) and trivial arithmetic operations. The encoding noise appearing on the uncontrolled half of the image samples is reduced by the application of structured, non-random initial phase terms so that speckle noise is also kept low. High quality reconstructions are obtained under temporal averaging of several SLM frames. Interlaced video within half of the addressable image area is readily deliverable without frame rate division. Our algorithm provides about 6X and 20X reduction in computational cost compared to IFTA and FIDOC algorithms, respectively. Simulations and experiments verify that the algorithm constitutes a promising option for real-time computation of phase CGHs.
Highlights
Computer-generated holograms (CGHs) have been researched for almost 50 years [1]
We carried out proof of concept holographic image projection (HIP) experiments with the setup illustrated in Fig. 9(a) to verify our CGH computation algorithm
A linear phase term is superimposed on the phase CGHs to perform off-axis reconstructions
Summary
Computer-generated holograms (CGHs) have been researched for almost 50 years [1]. In the early times, CGHs were implemented by printed binary masks or kinoforms [2,3]. In spite of the improvements in the computational power and parallel processing hardware such as FPGAs and GPUs, real-time operations still remain as a challenge due to lack of non-iterative direct solutions. Another disadvantage of most established phase CGH computation algorithms, especially in the HIP context, is related to speckle noise. In this way, we reduce encoding noise while keeping speckle noise low and get high quality reconstructions under temporal averaging.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
