Image quality improvement of polygon computer generated holography.

Quality of holographic reconstruction image is seriously affected by undesirable messy fringes in polygon-based computer generated holography. Here, several methods have been proposed to improve the image quality, including a modified encoding method based on spatial-domain Fraunhofer diffraction and a specific LED light source. Fast Fourier transform is applied to the basic element of polygon and fringe-invisible reconstruction is achieved after introducing initial random phase. Furthermore, we find that the image with satisfactory fidelity and sharp edge can be reconstructed by either a LED with moderate coherence level or a modulator with small pixel pitch. Satisfactory image quality without obvious speckle noise is observed under the illumination of bandpass-filter-aided LED. The experimental results are consistent well with the correlation analysis on the acceptable viewing angle and the coherence length of the light source.