Chromadepth is a patented system from the company Chromatek that produces a stereoscopic effect based upon differences in the diffraction of color through a special prism-like holographic film fitted into glasses. Chromadepth glasses purposely exacerbate chromatic aberration and give the illusion of colors taking up different positions in space, with red being in front, blue being behind; this works well with the sky, sea or grass as a background, redder objects in the foreground. With computer-controlled etching, the technology to create thin plastic sheets with thousands of microscopic ‘prism’ lenses that can magnify or diffract light can be made. Since violet light has more energy than red, bends more when refracted, some lenses can distort an image if they don’t focus all of the colors at the same point; this distortion is called chromatic aberration. One type of film etching creates lenses that deliberately exaggerate this aberration, separating the colors of an image into different convergence points in the visual field.
It’s a patented process called ChromaDepth™. Glasses with ChromaDepth™ diffraction lenses create an artificial visual depth. “Warm” colors, toward the infrared end of the spectrum, appear closer, ‘cool” colors toward the violet end appear further away. Any 2D media piece in colors can be given a 3D effect as long as the color spectrum is put into use with the foreground being in red, the background in blue. From front to back the scheme follows the visible light spectrum, from red to orange, yellow and blue; this means. As a result, ChromaDepth works best with artificially produced or enhanced pictures, since the color indicates the depth. Unlike anaglyph images or polarization, creating real-life ChromaDepth pictures without manual enhancement is impossible, since cameras cannot portray true depth. However, this gives ChromaDepth images a distinct advantage: unlike stereopsis-based schemes that require two images, ChromaDepth contains depth information in one image, which eliminates the ghosting seen in other schemes when one attempts to view them without 3D glasses.
Thus, ChromaDepth images can be viewed comfortably and legibly without glasses though the 3D effect will not be perceivable without them. ChromaDepth™ 3-D was invented by US researcher, Richard Steenblik, after he noticed that the bright colors on the screen of a TEMPEST video game seemed to lie in different depth planes; this triggered a quest to make this effect, known as chromostereoscopy, into a practical method for producing 3D images. In the course of eight years of after-hours experimentation, Mr. Steenblik created plastic prisms, glass double prisms, Fresnel prisms, liquid optics using glycerin and Chinese cinnamon oil held in wedge-shaped glass cells; these liquid glasses worked well, but were not suited for mass production. Mr. Steenblik and his business partner, Dr. Frederick Lauter, were about to give up when a new optical development came to their attention. Researchers at the Massachusetts Institute of Technology had developed binary optics, it was clear that binary optics provided the answer!
Optical devices use refraction, or diffraction to move light around. Optics which use refraction, such as lenses, are designed to reduce refraction; the binary optics found in ChromaDepth™ 3-D glasses, combine refraction and diffraction to make thin optics that act like thick glass prisms. After two years of development work with MIT, the ChromaDepth™ 3-D production solution was found. ChromaDepth™ lenses were first used commercially in June 1992. In 1997, American cable TV network Nickelodeon distributed Chromadepth glasses at Blockbuster Video and through some Kraft products, which could be used for special 3D segments on new programming that September, terming the glasses "Nogglegoggles" and the 3D format "Nogglevision". Rock band KISS utilized the Chromadepth process for an alternate verson of the music video for their 1998 single Psycho Circus, releasing it on VHS at that time with a free pair of glasses for viewing. Chromadepth glasses were utilized for the VH1 series I Love the'80s 3-D, with free pairs of glasses available at Best Buy locations.
Chromadepth glasses have been used and distributed for some haunted house and Halloween attractions for added visual appeal featuring custom glasses for patrons. Numerous books, special publications, promotional giveaways, children's toys have been released with or intended for use with Chromadepth glasses as well, notably including Crayola and Melissa & Doug's lines of 3D art and toy products, Disney's line of 3D Toy Story 3 products, among many others. 2D-plus-depth ChromaDepth Patent Chromatek company web site Oregon State University Daily ChromaDepth 3D Blog 3D ChromaDepth Animated Music Scores
Line of beauty
Line of beauty is a term and a theory in art or aesthetics used to describe an S-shaped curved line appearing within an object, as the boundary line of an object, or as a virtual boundary line formed by the composition of several objects. This theory originated with William Hogarth, is an essential part of Hogarth's theory of aesthetics as described in his Analysis of Beauty. According to this theory, S-shaped curved lines signify liveliness and activity and excite the attention of the viewer as contrasted with straight lines, parallel lines, or right-angled intersecting lines, which signify stasis, death, or inanimate objects. In contrast to grand compositional lines, which are found in Baroque or Rococo art, the serpentine line is not dictating the whole composition of a canvas. Instead, the line should be understood as being found in parts. Ogee William Hogarth's The Analysis of Beauty
Stereoscopic acuity stereoacuity, is the smallest detectable depth difference that can be seen in binocular vision. Stereoacuity is most explained by considering one of its earliest test, a two-peg device, named Howard-Dolman test after its inventors: The observer is shown a black peg at a distance of 6m. A second peg, below it, can be moved back and forth until it is just detectably nearer than the fixed one. Stereoacuity is this difference in the two positions, converted into an angle of binocular disparity, i.e. the difference in their binocular parallax. Conversion to the angle of disparity dγ is performed by inserting the position difference dz in the formula d γ = c a d z / z 2 where a is the interocular separation of the observer and z the distance of the fixed peg from the eye. To transfer dγ into the usual unit of minutes of arc, a multiplicative constant c is inserted whose value is 3437.75. In the calculation a, dz and z must be in the same units, feet, inches, cm or meters. For the average interocular distance of 6.5 cm, a target distance of 6m and a typical stereoacuity of 0.5 minute of arc, the just detectable depth interval is 8 cm.
As targets come closer, this interval gets smaller by the inverse square of the distance, so that an equivalent detectable depth interval at ¼ meter is 0.01 cm or the depth of impression of the head on a coin. These small values of normal stereoacuity, expressed in differences of either object distances, or angle of disparity, makes it a hyperacuity. Since the Howard-Dolman test described above is cumbersome, stereoacuity is measured using a stereogram in which separate panels are shown to each eye by superimposing them in a stereoscope using prisms or goggles with color or polarizing filters or alternating occlusion. A good procedure is a chart, analogous to the familiar Snellen visual acuity chart, in which one letter in each row differs in depth sequentially increasing in difficulty. For children the fly test is ideal: the image of a fly is transilluminated by polarized light. There is no equivalent in stereoacuity of the normal 20/20 visual acuity standard. In every case, the numerical score if expressed in disparity angle, depends to some extent on the test being used.
Superior observers under ideal conditions can achieve 0.1 arc min or better. The distinction between screening for the presence of stereopsis and a measurement of stereoacuity is valuable. To ascertain that depth can be seen in a binocular views, a test must be administered and not subject to deception; the random-dot stereogram is used for this purpose and has the advantage that for the uninitiated the object shape is unknown. It is made of random small pattern elements. A population study revealed a high incidence of good stereoacuity. Out of 188 biology students, 97.3 % could perform at 2.3 minutes of better. Optimum stereoacuity requires that the following mitigating factors be avoided: Low contrast Short duration exposures Fuzzy or spaced pattern elements. Uncorrected or unequally corrected refractive errors More than other such visual capabilities, the limits of stereopsis depend on the observer's familiarity with the situation. Stereo thresholds always improve several-fold, with training and involve perceptual factors, differing in their particulars for each test.
This is most vividly evident in the time it takes to "solve" a random-dot stereogram decreases between the first exposure and subsequent views Computer vision Visual acuity Review of 3D displays and stereo vision
Polarized 3D system
A polarized 3D system uses polarization glasses to create the illusion of three-dimensional images by restricting the light that reaches each eye. To present stereoscopic images and films, two images are projected superimposed onto the same screen or display through different polarizing filters; the viewer wears low-cost eyeglasses. As each filter passes only that light, polarized and blocks the light polarized in the opposite direction, each eye sees a different image; this is used to produce a three-dimensional effect by projecting the same scene into both eyes, but depicted from different perspectives. Multiple people can view the stereoscopic images at the same time. To present a stereoscopic motion picture, two images are projected superimposed onto the same screen through orthogonal polarizing filters; the viewer wears linearly polarized eyeglasses which contain a pair of orthogonal polarizing filters oriented the same as the projector. As each filter only passes light, polarised and blocks the orthogonally polarized light, each eye only sees one of the projected images, the 3D effect is achieved.
Linearly polarised glasses require the viewer to keep his or her head level, as tilting of the viewing filters will cause the images of the left and right channels to bleed over to the opposite channel. This can make prolonged viewing uncomfortable. To present a stereoscopic motion picture, two images are projected superimposed onto the same screen through circular polarizing filters of opposite handedness; the viewer wears eyeglasses. Light, left-circularly polarized is blocked by the right-handed analyzer, while right-circularly polarized light is blocked by the left-handed analyzer; the result is similar to that of stereoscopic viewing using linearly polarized glasses, except the viewer can tilt his or her head and still maintain left/right separation. As shown in the figure, the analyzing filters are constructed of a quarter-wave plate and a linearly polarized filter; the QWP always transforms circularly polarized light into linearly polarized light. However, the angle of polarization of the linearly polarized light produced by a QWP depends on the handedness of the circularly polarized light entering the QWP.
In the illustration, the left-handed circularly polarized light entering the analyzing filter is transformed by the QWP into linearly polarized light which has its direction of polarization along the transmission axis of the LPF. Therefore, in this case the light passes through the LPF. In contrast, right-handed circularly polarized light would have been transformed into linearly polarized light that had its direction of polarization along the absorbing axis of the LPF, at right angles to the transmission axis, it would have therefore been blocked. By rotating either the QWP or the LPF by 90 degrees about an axis perpendicular to its surface, one may build an analyzing filter which blocks left-handed, rather than right-handed circularly polarized light. Rotating both the QWP and the LPF by the same angle does not change the behaviour of the analyzing filter. Polarized light reflected from an ordinary motion picture screen loses most of its polarization, but the loss is negligible if a silver screen or aluminized screen is used.
This means that a pair of aligned DLP projectors, some polarizing filters, a silver screen, a computer with a dual-head graphics card can be used to form a high-cost system for displaying stereoscopic 3D data to a group of people wearing polarized glasses. In the case of RealD a circularly polarizing liquid crystal filter which can switch polarity 144 times per second is placed in front of the projector lens. Only one projector is needed. Sony features a new system called RealD XLS, which shows both circularly polarized images simultaneously: A single 4K projector displays two 2K images one above the other, a special lens attachment polarizes and projects the images on top of each other. Optical attachments can be added to traditional 35 mm projectors to adapt them for projecting film in the "over-and-under" format, in which each pair of images is stacked within one frame of film; the two images are superimposed on the screen. This is a cost-effective way to convert a theater for 3-D as all, needed are the attachments and a non-depolarizing screen surface, rather than a conversion to digital 3-D projection.
Thomson Technicolor produces an adapter of this type. When stereo images are to be presented to a single user, it is practical to construct an image combiner, using silvered mirrors and two image screens at right angles to one another. One image is seen directly through the angled mirror. Polarized filters are attached to the image screens and appropriately angled filters are worn as glasses. A similar technique uses a single screen with an inverted upper image, viewed in a horizontal partial reflector, with an upright image presented below the reflector, again with appropriate polarizers. Polarizing techniques are easier to apply with cathode ray tube technology than with Liquid crystal display. Ordinary LCD screens contain polarizers for control of pixel p
Parallax is a displacement or difference in the apparent position of an object viewed along two different lines of sight, is measured by the angle or semi-angle of inclination between those two lines. Due to foreshortening, nearby objects show a larger parallax than farther objects when observed from different positions, so parallax can be used to determine distances. To measure large distances, such as the distance of a planet or a star from Earth, astronomers use the principle of parallax. Here, the term parallax is the semi-angle of inclination between two sight-lines to the star, as observed when Earth is on opposite sides of the Sun in its orbit; these distances form the lowest rung of what is called "the cosmic distance ladder", the first in a succession of methods by which astronomers determine the distances to celestial objects, serving as a basis for other distance measurements in astronomy forming the higher rungs of the ladder. Parallax affects optical instruments such as rifle scopes, binoculars and twin-lens reflex cameras that view objects from different angles.
Many animals, including humans, have two eyes with overlapping visual fields that use parallax to gain depth perception. In computer vision the effect is used for computer stereo vision, there is a device called a parallax rangefinder that uses it to find range, in some variations altitude to a target. A simple everyday example of parallax can be seen in the dashboard of motor vehicles that use a needle-style speedometer gauge; when viewed from directly in front, the speed may show 60. As the eyes of humans and other animals are in different positions on the head, they present different views simultaneously; this is the basis of stereopsis, the process by which the brain exploits the parallax due to the different views from the eye to gain depth perception and estimate distances to objects. Animals use motion parallax, in which the animals move to gain different viewpoints. For example, pigeons down to see depth; the motion parallax is exploited in wiggle stereoscopy, computer graphics which provide depth cues through viewpoint-shifting animation rather than through binocular vision.
Parallax arises due to change in viewpoint occurring due to motion of the observer, of the observed, or of both. What is essential is relative motion. By observing parallax, measuring angles, using geometry, one can determine distance. Astronomers use the word "parallax" as a synonym for "distance measurement" by other methods: see parallax #Astronomy. Stellar parallax created by the relative motion between the Earth and a star can be seen, in the Copernican model, as arising from the orbit of the Earth around the Sun: the star only appears to move relative to more distant objects in the sky. In a geostatic model, the movement of the star would have to be taken as real with the star oscillating across the sky with respect to the background stars. Stellar parallax is most measured using annual parallax, defined as the difference in position of a star as seen from the Earth and Sun, i. e. the angle subtended at a star by the mean radius of the Earth's orbit around the Sun. The parsec is defined as the distance.
Annual parallax is measured by observing the position of a star at different times of the year as the Earth moves through its orbit. Measurement of annual parallax was the first reliable way to determine the distances to the closest stars; the first successful measurements of stellar parallax were made by Friedrich Bessel in 1838 for the star 61 Cygni using a heliometer. Stellar parallax remains the standard for calibrating other measurement methods. Accurate calculations of distance based on stellar parallax require a measurement of the distance from the Earth to the Sun, now based on radar reflection off the surfaces of planets; the angles involved in these calculations are small and thus difficult to measure. The nearest star to the Sun, Proxima Centauri, has a parallax of 0.7687 ± 0.0003 arcsec. This angle is that subtended by an object 2 centimeters in diameter located 5.3 kilometers away. The fact that stellar parallax was so small that it was unobservable at the time was used as the main scientific argument against heliocentrism during the early modern age.
It is clear from Euclid's geometry that the effect would be undetectable if the stars were far enough away, but for various reasons such gigantic distances involved seemed implausible: it was one of Tycho's principal objections to Copernican heliocentrism that in order for it to be compatible with the lack of observable stellar parallax, there would have to be an enormous and unlikely void between the orbit of Saturn and the eighth sphere. In 1989, the satellite Hipparcos was launched for obtaining improved parallaxes and proper motions for over 100,000 nearby stars, increasing the reach of the method tenfold. So, Hipparcos is only able to measure parallax angles for stars up to about 1,600 light-years away, a little more than one percent of the diameter of the Milky Way Galaxy; the European Space Agency's Gaia mission, launched in December 2013, will be able to measure parallax angles to an accuracy of 10 microarcseconds, thus mapping nearby stars up to a distance of tens of thousands of ligh
A stereoscope is a device for viewing a stereoscopic pair of separate images, depicting left-eye and right-eye views of the same scene, as a single three-dimensional image. A typical stereoscope provides each eye with a lens that makes the image seen through it appear larger and more distant and also shifts its apparent horizontal position, so that for a person with normal binocular depth perception the edges of the two images fuse into one "stereo window". In current practice, the images are prepared so that the scene appears to be beyond this virtual window, through which objects are sometimes allowed to protrude, but this was not always the custom. A divider or other view-limiting feature is provided to prevent each eye from being distracted by seeing the image intended for the other eye. Most people can, with practice and some effort, view stereoscopic image pairs in 3D without the aid of a stereoscope, but the physiological depth cues resulting from the unnatural combination of eye convergence and focus required will be unlike those experienced when viewing the scene in reality, making an accurate simulation of the natural viewing experience impossible and tending to cause eye strain and fatigue.
Although more recent devices such as Realist-format 3D slide viewers and the View-Master are stereoscopes, the word is now most associated with viewers designed for the standard-format stereo cards that enjoyed several waves of popularity from the 1850s to the 1930s as a home entertainment medium. Devices such as polarized and shutter glasses which are used to view two superimposed or intermingled images, rather than two physically separate images, are not categorized as stereoscopes; the earliest type of stereoscope was invented by Sir Charles Wheatstone in 1838. It used a pair of mirrors at 45 degree angles to the user's eyes, each reflecting a picture located off to the side, it demonstrated the importance of binocular depth perception by showing that when two pictures simulating left-eye and right-eye views of the same object are presented so that each eye sees only the image designed for it, but in the same location, the brain will fuse the two and accept them as a view of one solid three-dimensional object.
Wheatstone's stereoscope was introduced in the year before the first practical photographic process became available, so drawings were used. This type of stereoscope has the advantage that the two pictures can be large if desired. Contrary to a common assertion, David Brewster did not invent the stereoscope, as he himself was at pains to make clear. A rival of Wheatstone, Brewster credited the invention of the device to a Mr. Elliot, a "Teacher of Mathematics" from Edinburgh, according to Brewster, conceived of the idea as early as 1823 and, in 1839, constructed "a simple stereoscope without lenses or mirrors", consisting of a wooden box 18 inches long, 7 inches wide and 4 inches high, used to view drawn landscape transparencies, since photography had yet to be invented. Brewster's personal contribution was the suggestion to use lenses for uniting the dissimilar pictures in 1849; this allowed a reduction in size, creating hand-held devices, which became known as Brewster Stereoscopes, much admired by Queen Victoria when they were demonstrated at the Great Exhibition of 1851.
Brewster was unable to find in Britain an instrument maker capable of working with his design, so he took it to France, where the stereoscope was improved by Jules Duboscq who made stereoscopes and stereoscopic daguerreotypes, a famous picture of Queen Victoria, displayed at The Great Exhibition. Overnight a 3D industry developed and 250,000 stereoscopes were produced and a great number of stereoviews, stereo cards, stereo pairs or stereographs were sold in a short time. Stereographers were sent throughout the world to capture views for the new medium and feed the demand for 3D. Cards were printed with these views with explanatory text when the cards were looked at through the double-lensed viewer, sometimes called a stereopticon, a common misnomer. In 1861 Oliver Wendell Holmes created and deliberately did not patent a handheld, much more economical viewer than had been available before; the stereoscope, which dates from the 1850s, consisted of two prismatic lenses and a wooden stand to hold the stereo card.
This type of stereoscope remained in production for a century and there are still companies making them in limited production currently. In the mid-20th century the View-Master stereoscope, with its rotating cardboard disks containing image pairs, was popular first for'virtual tourism' and as a toy. In 2010, Hasbro started producing a stereoscope designed to hold an iPhone or iPod Touch, called the My3D. In 2014, Google released. Apps on the mobile phone substitute for stereo cards; the underlying technology is otherwise unchanged from earlier stereoscopes. Several fine arts photographers and graphic artists have and continue to produce original artwork to be viewed using stereoscopes. A simple stereoscope is limited in the size of the image. A more complex stereoscope uses a pair of horizontal periscope-like devices, allowing the use of larger images that can present more detailed information in a wider field of view; the stereoscope is an instrument in which two photographs of the same object, taken from different angles, are presented, one to each eye.
This recreates the way which in natural vis
Glossary of ballet
Because ballet became formalized in France, a significant part of ballet terminology is in the French language. If a step is done "à la seconde," it is done to the side. One of the directions of body, facing the audience, arms in second position, with one leg extended either to fourth position in front or fourth position behind. Touching the floor. Italian, or French adage, meaning'slowly, at ease.' Slow movements performed with grace. One of the typical exercises of a traditional ballet class, done both at barre and in center, featuring slow, controlled movements; the section of a grand pas referred to as grand adage, that features dance partnering. Brisk, lively motion. An attribute of many movements, including those in which a dancer is airborne. Used in ballet to refer to all jumps, regardless of tempo. A category of exercises found in e.g. petit allegro and grand allegro. Refers to a hand and arm position when the fingers and elbows are extended and elongated, rather than forming the usual soft curve.
The apparent elegance and precision exhibited by a accomplished dancer. In dance, arabesque is a body position in which a dancer stands on one leg with the other leg extended, behind the body; the arm positions can vary and are allongé. The foot of the supporting leg may be flat on the floor, on the ball of the foot, or on the tips of the toes. A position of the hand. Rounded, in contrast with allongé. Sometimes pas assemblé. A jump that takes off from one foot and lands on two feet; when initiated with two feet on the ground the working leg performs a battement glissé/dégagé, brushing out. The dancer launches into a jump, with the second foot meeting the first foot before landing. A petit assemblé is; the dancer does a small jump to meet the first foot. A position in which a dancer stands on one leg while the other leg is raised and turned out with knee bent to form an angle of 90° between the thigh and the lower leg; the height of the knee versus the foot and the angle of the knee flexion will vary depending on the techniques.
The working leg can be held behind, to the side of the body. The alignment of the thigh compared to the midline in Attitude derrière will vary depending on the techniques; the foot of the supporting leg may be en demi-pointe, or en pointe. The standing leg can bend. A movement towards the front, as opposed to en arrière, conversely a movement towards the back. For example, a step travelling en avant moves forwards towards the audience, as in sissonne en avant. A movement towards the back, as opposed to en avant. A rocking sequence of three steps—fondu, relevé, fondu —executed in three counts. Before the first count, one foot extends in a dégagé to the front or rear; the second foot in the sequence assembles behind the first to relevé in fourth position. Swinging the working leg between front and back through first position in conjunction with grands battements or attitudes and involving seesaw like shifting of the upper body in opposition to the legs. Similar to en cloche. A principal female ballet dancer.
The foundational principles of body movement and form used in ballet. A ballet fan or enthusiast; the word is of Russian origin c. 1930, with the suffix -mane coming from maniya. Showing lightness of movement in leaps and jumps. A dancer exhibiting ballon will appear to spring effortlessly, float in mid-air, land like a balloon. In classical ballet, the term ballonné is a step; the knee is bent and the foot brought to a sur le cou-de-pied position. This can be done as a relevé or jump. A ballotté is a jumping step in classical ballet that consists of coupé dessous and small developpés performed with a rocking and swinging movement; the step can be performed with the leg extensions at 90 degrees. A sturdy horizontal bar waist height, used during ballet warm-up exercises and training. Fixed barres are mounted on mirror-covered walls. An alternating side-to-side movement of the working leg. Performed in multiples and in rapid succession so that the working foot appears to be fluttering or vibrating. A general term for jumps in which the legs open sideways and close multi