Improved Smart Pseudoscopic-to-Orthoscopic Conversion Algorithm for Integral Imaging With Pixel Information Averaging

The smart pseudoscopic-to-orthoscopic conversion (SPOC) algorithm can synthesize a new elemental image array (EIA) using the already captured EIA, but the algorithm only relies on one simulated ray to establish the mapping relationship between the display pixels and the synthetic pixels. This paper improves the SPOC algorithm and proposes the average SPOC algorithm, which fully considers the converging effect of the synthetic lens on the ray. In the average SPOC algorithm, the simulated rays start from the synthetic pixel, pass through the upper and lower edges of the corresponding synthetic lens, and intersect the display lenses, respectively. Then, the value of the synthetic pixel is equivalent to the average value of display pixels, which correspond to the display lenses covered by the rays. Theoretical analysis points out that the average SPOC algorithm can effectively alleviate the matching error between the display pixels and the synthetic pixels, thereby improving the accuracy of the synthetic elemental image array (SEIA) and the reconstruction effect. According to the experimental results we get, the superiority of the average SPOC algorithm is verified.

Resolution Enhancement of Spherical Wave-Based Holographic Stereogram with Large Depth Range

The resolution-priority holographic stereogram uses spherical waves focusing on the central depth plane (CDP) to reconstruct 3D images. The image resolution near the CDP can be easily enhanced by modifying three parameters: the capturing depth, the pixel size of elemental image and the focal length of lens array. However, the depth range may decrease as a result. In this paper, the resolution characteristics were analyzed in a geometrical imaging model, and three corresponding methods were proposed: a numerical method was proposed to find the proper capturing depth; a partial aperture filtering technique was proposed after reducing pixel size; the moving array lenslet technique was introduced after increasing focal length and partial aperture filtering. Each method can enhance resolution within the total depth range. Simulation and optical experiments were performed to verify the proposed methods.

Performance Enhanced Elemental Array Generation for Integral Image Display Using Pixel Fusion

Integral imaging is an emerging three-dimensional display technology. However, some inherent issues such as depth inversion has restricted its development. As such, this paper proposes a pixel fusion technique to generate elemental image arrays and overcome pseudoscopic problems occurring in sparse imaging environments. The similarity between the aimed displayed rays and the two adjacent captured rays of an object in a parallel light field was measured by the ratio of the spatial distance of the displayed and captured rays to the interval of the adjacent captured light. Displayed pixel values were acquired for the parallel captured rays. Corresponding pixel position errors were determined in sparse capture conditions and the method was further improved by using the position errors to identify the correct pixel, resulting in higher image quality. The proposed technique does not require manual adjustment of reference planes or other parameters, even at low capturing densities. This provides added convenience and may reduce capturing costs in actual scenes. Experiments using two bricks in virtual scenes under 9 × 9 to 137 × 137 capture cameras were conducted, and the quality of the generated elemental image array was compared with smart pseudoscopic-to-orthoscopic conversion (SPOC). The peak signal-to-noize ratio (PSNR) and structural similarity (SSIM) values showed the effectiveness of the proposed technique. The optical reconstruction results from both real and virtual scenes demonstrated improvements in vision of reconstructed three-dimensional scenes.