Real-time photorealistic computer-generated holograms based on backward ray tracing and wavefront recording planes

Holograms can reconstruct the complete optical wave field of a three-dimensional (3D) scene. However, generating traditional computer-generated holograms (CGHs) requires significant computing time. Here, a CGH method is presented based on backward ray tracing and wavefront recording planes (WRPs). Ray tracing is able to render more complex and photorealistic images for different illuminations and circumstances. Rays are parallelly launched and traced to obtain ray-object intersections, and then the complex wave field of the effective pixels in the WRP is determined. A CGH is generated by the diffracted calculation from the WRP to the hologram plane using fast Fourier transform (FFT) and inverse FFT algorithms. Experimental results demonstrate the effectiveness of the proposed method. Compared with traditional CGHs, the rate of CGH generation and optical reconstruction improves to 35.6 frames per second, achieving the real-time rendering and interactivity.