(Edward Trent, 1972, Bulletin of the Stereoscopic Society.) Alternatively, one can relax the eyes to diverge them farther from the wall, so that the wallpaper appears to float at a distant location farther than its actual distance.įigure 4: Geometric pattern autostereogram of a crystalline structure. One sees the wallpaper floating in space in front of its true position. Now the visual patterns viewed by the eyes are identical, except for the unpaired parts of the pattern in far peripheral vision, but the convergence angle is closer than the wall.
At a certain point, one part of the repeating pattern is imaged in central vision of the left eye and that part's neighbour, immediately to the left, is imaged in central vision of the right eye. To see this illusion, view a flat wall covered with a wallpaper showing a regular, horizontally repeating pattern then converge the eyes on a point in space closer than the wall. He observed, and worked out the principles of, the wallpaper illusion. The first phase was the early conceptual development, which began with Sir David Brewster in 1844. The history of the autostereogram falls into five phases. In order to do so, however, the viewer must overcome the natural tendency of the eyes to focus at the convergence distance, and enable the eyes to refocus at the plane of the image. The disparity structure may be designed to correspond to the depth map of any desired three-dimensional scene, which is perceived when the eyes are held at the appropriate convergence angle. When the eyes either converge or diverge at the distance of the pattern repeat, small differences between adjacent pattern cycles provide binocular disparities that are interpreted by the viewer as differences in depth. When viewing with normal convergence of the eyes on the physical plane, the image appears only as a flat repeating pattern. The principle of the autostereogram is a horizontally repetitive image in which the repeated pattern is modulated in such a way that the image can be viewed with an abnormal convergence or divergence angle to generate the visual impression of a stereoscopic depth image within the space of the pattern. Christopher Tyler, The Smith-Kettlewell Eye Research InstituteĪutostereogram refers to a single-image form of stereograms that can be free-viewed to achieve a stereoscopic, three-dimensional (3D), depth effect without a stereoscope or any other artificial aids to binocular fusion (see Figure 1). Numerical simulations and optical experiments have demonstrated that the proposed method can reconstruct quality 3D images with reduced computational load.Dr. When the hogel size equals 1 mm, the signal-to-noise ratio of the diffraction calculation is above 39 dB with a propagation distance longer than 10 mm. The algorithm is compatible with computer graphics rendering techniques and robust for holograms with different parameters. The sliced layers can provide accurate depth cues for reconstruction since the geometric information of the 3D scene is faithfully matched. Each hogel is calculated with inverse Fresnel diffraction by slicing the viewing frustum according to the depth image. The hologram is spatially partitioned into multiple holographic elements (hogels) to provide the occlusion effect and motion parallax by use of multiple viewpoint rendering. We propose an efficient algorithm using layered holographic stereogram for three-dimensional (3D) computer-generated holograms. Note: Author names will be searched in the keywords field, also, but that may find papers where the person is mentioned, rather than papers they authored.Use a comma to separate multiple people: J Smith, RL Jones, Macarthur.Use these formats for best results: Smith or J Smith.For best results, use the separate Authors field to search for author names.Use quotation marks " " around specific phrases where you want the entire phrase only.Question mark (?) - Example: "gr?y" retrieves documents containing "grey" or "gray".Asterisk ( * ) - Example: "elect*" retrieves documents containing "electron," "electronic," and "electricity".Improve efficiency in your search by using wildcards.Example: (photons AND downconversion) - pump.Example: (diode OR solid-state) AND laser.
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