Integral imaging

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Integral imaging is a three-dimensional imaging technique that captures and reproduces a light field by using a two-dimensional array of microlenses (or lenslets), sometimes called a fly's-eye lens, normally without the aid of a larger overall objective or viewing lens. In capture mode, in which a film or detector is coupled to the microlens array, each microlens allows an image of the subject as seen from the viewpoint of that lens's location to be acquired. In reproduction mode, in which an object or source array is coupled to the microlens array, each microlens allows each observing eye to see only the area of the associated micro-image containing the portion of the subject that would have been visible through that space from that eye's location. The optical geometry can perhaps be visualized more easily by substituting pinholes for the microlenses, as has actually been done for some demonstrations and special applications.

Contents

A display using integral imaging is a type of light field display.

The result is a visual reproduction complete with all significant depth cues, including parallax in all directions, perspective that changes with the position and distance of the observer, and, if the lenses are small enough and the images of sufficient quality, the cue of accommodation — the adjustments of eye focus required to clearly see objects at different distances. Unlike the voxels in a true volumetric display, the image points perceived through the microlens array are virtual and have only a subjective location in space, allowing a scene of infinite depth to be displayed without resorting to an auxiliary large magnifying lens or mirror.

Integral imaging was partly inspired by barrier grid autostereograms and in turn partly inspired lenticular printing.

Etymology

Inventor Gabriel Lippmann called the technique "photographie intégrale" (in French). It is usually translated literally as "integral photography", which suggests the integration of a whole image from parts of many small ones. However, a more usual meaning of the French word "intégrale" is "complete" or "unabridged", so that "complete photography" is another valid translation of Lippmann's perhaps deliberately ambiguous name for it.

History

On March 2, 1908 Nobel prize winning French physicist Gabriel Lippmann presented his ideas for "Photographie intégrale", based on insect eyes. He was probably also inspired by the barrier grid autostereograms of Frederic Ives and Eugène Estanave, representing Estanave at several presentations of Estanave's works at the French Academy of Sciences. Lippmann suggested to use a screen of tiny lenses. Spherical segments should be pressed into a sort of film with photographic emulsion on the other side. The screen would be placed inside a lightproof holder and on a tripod for stability. When exposed each tiny lens would function as a camera and record the surroundings from a slightly different angle than neighboring lenses. When developed and lit from behind the lenses should project the life-size image of the recorded subject in space. He could not yet present concrete results in March 1908, but by the end of 1908 he claimed to have exposed some Integral photography plates and to have seen the "resulting single, full-sized image". However, the technique remained experimental since no material or technique seemed to deliver the optical quality desired. At the time of his death in 1921 Lippmann reportedly had a system with only twelve lenses. [1]

Eugène Estanave performed further experiments with Lippmann's technique. He exhibited an integral photograph in 1925 and published about his findings in La Nature. In 1930 he had 432 lenses in a 6.5 x 9 cm plate with viewable results, but then abandoned the lenticular screen and continued his integral photography experiments with pinholes. [1]

Louis Lumière worked on integral photography and corresponded with Lippman about the technique. Lumière patented a system a few years after Lippmann's death, but never seems to have actually manufactured lenticular screens. [1]

Integral video

See also

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<span class="mw-page-title-main">Pinhole camera</span> Type of camera

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<span class="mw-page-title-main">Autochrome Lumière</span> Early color photography process

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<span class="mw-page-title-main">Stereoscopy</span> Technique for creating or enhancing the illusion of depth in an image

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<span class="mw-page-title-main">Lippmann plate</span>

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<span class="mw-page-title-main">Color photography</span> Photography that reproduces colors

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<span class="mw-page-title-main">Autostereogram</span> Visual illusion of 3D scene achieved by unfocusing eyes when viewing specific 2D images

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<span class="mw-page-title-main">Lenticular printing</span> Technology for creating optical illusions

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<span class="mw-page-title-main">3D display</span> Display device

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<span class="mw-page-title-main">Gabriel Lippmann</span> French physicist born in Luxembourg

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<span class="mw-page-title-main">Lenticular lens</span>

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<span class="mw-page-title-main">Autostereoscopy</span> Any method of displaying stereoscopic images without the use of special headgear or glasses

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<span class="mw-page-title-main">PHSCologram</span>

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<span class="mw-page-title-main">Microlens</span>

A microlens is a small lens, generally with a diameter less than a millimetre (mm) and often as small as 10 micrometres (µm). The small sizes of the lenses means that a simple design can give good optical quality but sometimes unwanted effects arise due to optical diffraction at the small features. A typical microlens may be a single element with one plane surface and one spherical convex surface to refract the light. Because micro-lenses are so small, the substrate that supports them is usually thicker than the lens and this has to be taken into account in the design. More sophisticated lenses may use aspherical surfaces and others may use several layers of optical material to achieve their design performance.

<span class="mw-page-title-main">3D stereo view</span> Enables viewing of objects through any stereo pattern

A 3D stereo view is the viewing of objects through any stereo pattern.

A 3D display is multiscopic if it projects more than two images out into the world, unlike conventional 3D stereoscopy, which simulates a 3D scene by displaying only two different views of it, each visible to only one of the viewer's eyes. Multiscopic displays can represent the subject as viewed from a series of locations, and allow each image to be visible only from a range of eye locations narrower than the average human interocular distance of 63 mm. As a result, not only does each eye see a different image, but different pairs of images are seen from different viewing locations.

<span class="mw-page-title-main">Barrier-grid animation and stereography</span> Animation method

Barrier-grid animation or picket-fence animation is an animation effect created by moving a striped transparent overlay across an interlaced image. The barrier-grid technique originated in the late 1890s, overlapping with the development of parallax stereography (Relièphographie) for 3D autostereograms. The technique has also been used for color-changing pictures, but to a much lesser extent.

Lightfieldmicroscopy (LFM) is a scanning-free 3-dimensional (3D) microscopic imaging method based on the theory of light field. This technique allows sub-second (~10 Hz) large volumetric imaging with ~1 μm spatial resolution in the condition of weak scattering and semi-transparence, which has never been achieved by other methods. Just as in traditional light field rendering, there are two steps for LFM imaging: light field capture and processing. In most setups, a microlens array is used to capture the light field. As for processing, it can be based on two kinds of representations of light propagation: the ray optics picture and the wave optics picture. The Stanford University Computer Graphics Laboratory published their first prototype LFM in 2006 and has been working on the cutting edge since then.

References

  1. 1 2 3 Timby, Kim (31 July 2015). 3D and Animated Lenticular Photography. ISBN   9783110448061.
  2. Zyga, Lisa (August 27, 2010). "Integral 3D TV system projects a promising future (w/ Video)".
  3. Archived at Ghostarchive and the Wayback Machine : "Integral 3D TV - Creating Autostereoscopic Content from Multi-perspective Videos #DigInfo". YouTube .
  4. Archived at Ghostarchive and the Wayback Machine : "Glasses-Free 3D Display Using Integral Imaging - Toshiba : DigInfo". YouTube .