3d Anaglyph Movies

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Wesley Godinez

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Aug 3, 2024, 6:01:08 PM8/3/24
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Anaglyph 3D is the stereoscopic 3D effect achieved by means of encoding each eye's image using filters of different (usually chromatically opposite) colors, typically red and cyan. Anaglyph 3D images contain two differently filtered colored images, one for each eye. When viewed through the "color-coded" "anaglyph glasses", each of the two images reaches the eye it's intended for, revealing an integrated stereoscopic image. The visual cortex of the brain fuses this into the perception of a thre...

Maybe it could be possible to introduce this feature as an layer effect(?). The z-order of objects could define how far an object is and artificial depth could be created. Simple 2D games could have a benifit with anaglyph 3D against other games which are made with different engines(?).

Anaglyph 3D is the stereoscopic 3D effect achieved by means of encoding each eye's image using filters of different (usually chromatically opposite) colors, typically red and cyan. Anaglyph 3D images contain two differently filtered colored images, one for each eye. When viewed through the "color-coded" "anaglyph glasses", each of the two images reaches the eye it's intended for, revealing an integrated stereoscopic image. The visual cortex of the brain fuses this into the perception of a three-dimensional scene or composition.

Anaglyph images have seen a recent resurgence due to the presentation of images and video on the Web, Blu-ray Discs, CDs, and even in print. Low cost paper frames or plastic-framed glasses hold accurate color filters that typically, after 2002, make use of all 3 primary colors. The norm is red and cyan, with red being used for the left channel. The cheaper filter material used in the monochromatic past dictated red and blue for convenience and cost. There is a material improvement of full color images with the cyan filter, especially for accurate skin tones.

Video games, theatrical films, and DVDs can be shown in the anaglyph 3D process. Practical images, for science or design, where depth perception is useful, include the presentation of full scale and microscopic stereographic images. Examples from NASA include Mars rover imaging, and the solar investigation, called STEREO, which uses two orbital vehicles to obtain the 3D images of the sun. Other applications include geological illustrations by the United States Geological Survey, and various online museum objects. A recent application is for stereo imaging of the heart using 3D ultra-sound with plastic red/cyan glasses.

Anaglyph images are much easier to view than either parallel (diverging) or crossed-view pairs stereograms. However, these side-by-side types offer bright and accurate color rendering, not easily achieved with anaglyphs. Also, extended use of the "color-coded" "anaglyph glasses" can cause discomfort, and the afterimage caused by the colors of the glasses may temporarily affect the viewer's visual perception of real life objects. Recently,[timeframe?] cross-view prismatic glasses with adjustable masking have appeared, that offer a wider image on the new HD video and computer monitors.

The oldest known description of anaglyph images was written in August 1853 by W. Rollmann in Stargard about his "Farbenstereoscope" (color stereoscope). He had the best results viewing a yellow/blue drawing with red/blue glasses. Rollmann found that with a red/blue drawing the red lines were not as distinct as yellow lines through the blue glass.[1]

In 1858, in France, Joseph D'Almeida [fr] delivered a report to l'Acadmie des sciences describing how to project three-dimensional magic lantern slide shows using red and green filters to an audience wearing red and green goggles.[2] Subsequently, he was chronicled as being responsible for the first realisation of 3D images using anaglyphs.[3]

Louis Ducos du Hauron produced the first printed anaglyphs in 1891.[4] This process consisted of printing the two negatives which form a stereoscopic photograph on to the same paper, one in blue (or green), one in red. The viewer would then use colored glasses with red (for the left eye) and blue or green (right eye). The left eye would see the blue image which would appear black, whilst it would not see the red; similarly the right eye would see the red image, this registering as black. Thus a three dimensional image would result.

William Friese-Green created the first three-dimensional anaglyphic motion pictures in 1889, which had public exhibition in 1893.[5] 3-D films enjoyed something of a boom in the 1920s. [6] As late as 1954, films such as Creature from the Black Lagoon remained very successful. Originally shot and exhibited using the Polaroid system, Creature from the Black Lagoon was successfully reissued much later in an anaglyph format so it could be shown in cinemas without the need for special equipment. Although not anaglyphic, Jaws 3-D was a box-office success in 1983. At present the excellent quality of computer displays and user-friendly stereo-editing programs offer new and exciting possibilities for experimenting with anaglyph stereo.

A stereo pair is a pair of images from slightly different perspectives at the same time. Objects closer to the camera(s) have greater differences in appearance and position within the image frames than objects further from the camera.

Historically cameras captured two color filtered images from the perspective of the left and right eyes which were projected or printed together as a single image, one side through a red filter and the other side through a contrasting color such as blue or green or mixed cyan. One may typically use an image processing computer program to simulate the effect of using color filters, using as a source image a pair of either color or monochrome images. This is called mosaicing or image stitching.

In the 1970s filmmaker Stephen Gibson filmed direct anaglyph blaxploitation and adult movies. His "Deep Vision" system replaced the original camera lens with two color-filtered lenses focused on the same film frame.[7] In the 1980s, Gibson patented his mechanism.[8]

Many computer graphics programs provide the basic tools (typically layering and adjustments to individual color channels to filter colors) required to prepare anaglyphs from stereo pairs. In simple practice, the left eye image is filtered to remove blue & green. The right eye image is filtered to remove red. The two images are usually positioned in the compositing phase in close overlay registration (of the main subject). Plugins for some of these programs as well as programs dedicated to anaglyph preparation are available which automate the process and require the user to choose only a few basic settings.

There also exist methods for making anaglyphs using only one image, a process called stereo conversion. In one, individual elements of a picture are horizontally offset in one layer by differing amounts with elements offset further having greater apparent changes in depth (either forward or back depending on whether the offset is to the left or right). This produces images that tend to look like elements are flat standees arranged at various distances from the viewer similar to cartoon images in a View-Master.

A more sophisticated method involves use of a depth map (a false color image where color indicates distance, for example, a grayscale depth map could have lighter indicate an object closer to the viewer and darker indicate an object further away).[9] As for preparing anaglyphs from stereo pairs, stand-alone software and plug-ins for some graphics apps exist which automate production of anaglyphs (and stereograms) from a single image or from an image and its corresponding depth map.

As well as fully automatic methods of calculating depth maps (which may be more or less successful), depth maps can be drawn entirely by hand. Also developed are methods of producing depth maps from sparse or less accurate depth maps.[10] A sparse depth map is a depth map consisting of only a relatively few lines or areas which guides the production of the full depth map. Use of a sparse depth map can help overcome auto-generation limitations. For example, if a depth finding algorithm takes cues from image brightness an area of shadow in the foreground may be incorrectly assigned as background. This misassignment is overcome by assigning the shaded area a close value in the sparse depth map.

Viewing anaglyphs through spectrally opposed glasses or gel filters enables each eye to see independent left and right images from within a single anaglyphic image. Red-cyan filters can be employed because our vision processing systems use red and cyan comparisons, as well as blue and yellow, to determine the color and contours of objects.[11]

In a red-cyan anaglyph, the eye viewing through the red filter sees red within the anaglyph as "white", and the cyan within the anaglyph as "black". The eye viewing through the cyan filter perceives the opposite.[12]

Actual black or white in the anaglyph display, being void of color, are perceived the same by each eye. The brain blends together the red and cyan channeled images as in regular viewing but only green and blue are perceived. Red is not perceived because red equates with white through red gel and is black through cyan gel. Green and blue, however, are perceived through cyan gel.[citation needed]

Complementary color anaglyphs employ one of a pair of complementary color filters for each eye. The most common color filters used are red and cyan. Employing tristimulus theory, the eye is sensitive to three primary colors, red, green, and blue. The red filter admits only red, while the cyan filter blocks red, passing blue and green (the combination of blue and green is perceived as cyan). If a paper viewer containing red and cyan filters is folded so that light passes through both, the image will appear black. Another recently[timeframe?] introduced form employs blue and yellow filters. (Yellow is the color perceived when both red and green light passes through the filter.)

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