The magic lantern, also known by its Latin name lanterna magica, was an early type of image projector that used pictures—paintings, prints, or photographs—on transparent plates, one or more lenses, and a light source. Because a single lens inverts an image projected through it, slides were inserted upside down in the magic lantern, rendering the projected image correctly oriented.
Chroma key compositing, or chroma keying, is a visual-effects and post-production technique for compositing (layering) two or more images or video streams together based on colour hues. The technique has been used in many fields to remove a background from the subject of a photo or video – particularly the newscasting, motion picture, and video game industries. A colour range in the foreground footage is made transparent, allowing separately filmed background footage or a static image to be inserted into the scene. The chroma keying technique is commonly used in video production and post-production. This technique is also referred to as colour keying, colour-separation overlay, or by various terms for specific colour-related variants such as green screen or blue screen; chroma keying can be done with backgrounds of any colour that are uniform and distinct, but green and blue backgrounds are more commonly used because they differ most distinctly in hue from any human skin colour. No part of the subject being filmed or photographed may duplicate the colour used as the backing, or the part may be erroneously identified as part of the backing.
A planetarium is a theatre built primarily for presenting educational and entertaining shows about astronomy and the night sky, or for training in celestial navigation.
Infrared cut-off filters, sometimes called IR filters or heat-absorbing filters, are designed to reflect or block near-infrared wavelengths while passing visible light. They are often used in devices with bright incandescent light bulbs to prevent unwanted heating. There are also filters which are used in solid state video cameras to block IR due to the high sensitivity of many camera sensors to near-infrared light. These filters typically have a blue hue to them as they also sometimes block some of the light from the longer red wavelengths.
A slide projector is an optical device for projecting enlarged images of photographic slides onto a screen. Many projectors have mechanical arrangements to show a series of slides loaded into a special tray sequentially.
An overhead projector, like a film or slide projector, uses light to project an enlarged image on a screen, allowing the view of a small document or picture to be shared with a large audience.
An LCD projector is a type of video projector for displaying video, images or computer data on a screen or other flat surface. It is a modern equivalent of the slide projector or overhead projector. To display images, LCD projectors typically send light from a metal-halide lamp through a prism or series of dichroic filters that separates light to three polysilicon panels – one each for the red, green and blue components of the video signal. As polarized light passes through the panels, individual pixels can be opened to allow light to pass or closed to block the light. The combination of open and closed pixels can produce a wide range of colors and shades in the projected image.
A video projector is an image projector that receives a video signal and projects the corresponding image onto a projection screen using a lens system. Video projectors use a very bright ultra-high-performance lamp, Xenon arc lamp, metal halide lamp, LED or solid state blue, RB, RGB or fiber-optic lasers to provide the illumination required to project the image. Most modern projectors can correct any curves, blurriness and other inconsistencies through manual settings.
Digital light processing (DLP) is a set of chipsets based on optical micro-electro-mechanical technology that uses a digital micromirror device. It was originally developed in 1987 by Larry Hornbeck of Texas Instruments. While the DLP imaging device was invented by Texas Instruments, the first DLP-based projector was introduced by Digital Projection Ltd in 1997. Digital Projection and Texas Instruments were both awarded Emmy Awards in 1998 for the DLP projector technology. DLP is used in a variety of display applications from traditional static displays to interactive displays and also non-traditional embedded applications including medical, security, and industrial uses.
A movie projector is an opto-mechanical device for displaying motion picture film by projecting it onto a screen. Most of the optical and mechanical elements, except for the illumination and sound devices, are present in movie cameras. Modern movie projectors are specially built video projectors.
An enlarger is a specialized transparency projector used to produce photographic prints from film or glass negatives, or from transparencies.
A slide show, or slideshow, is a presentation of a series of still images (slides) on a projection screen or electronic display device, typically in a prearranged sequence. The changes may be automatic and at regular intervals or they may be manually controlled by a presenter or the viewer. Slide shows originally consisted of a series of individual photographic slides projected onto a screen with a slide projector, as opposed to the video or computer-based visual equivalent, in which the slides are not individual physical objects.
The Slide Cube Projector is a slide projector and system, manufactured and marketed by Bell & Howell, which was introduced in 1970 and marketed through the 1980s. The projector derived its name from its transparent cubical plastic slide storage magazine, approximately 5.5 cm (2.2 in) in each dimension, that held 36 to 44 slides, depending on the mount thickness. The magazine used a sliding lid to hold the slides in place. Unlike competing systems which used straight tray or carousel magazines, the slides in a Slide Cube are stacked on top of each other rather than stored in separate slots.
Compositing is the process or technique of combining visual elements from separate sources into single images, often to create the illusion that all those elements are parts of the same scene. Live-action shooting for compositing is variously called "chroma key", "blue screen", "green screen" and other names. Today, most compositing is achieved through digital image manipulation. Pre-digital compositing techniques, however, go back as far as the trick films of Georges Méliès in the late 19th century, and some are still in use.
Precursors of film are concepts and devices that have much in common with the later art and techniques of cinema.
Document cameras, also known as visual presenters, visualizers, digital overheads, or docucams, are high-resolution real-time image capture devices used to display an object to a large audience, such as in a classroom or a lecture hall. They can also serve as replacements for image scanners. Similar to opaque projectors, document cameras can magnify and project the images of actual, three-dimensional objects, as well as transparencies.
A structured-light 3D scanner is a device that measures the three-dimensional shape of an object by projecting light patterns—such as grids or stripes—onto it and capturing their deformation with cameras. This technique allows for precise surface reconstruction by analyzing the displacement of the projected patterns, which are processed into detailed 3D models using specialized algorithms.
A Linnebach lantern or Linnebach projector is a lensless projection system used in theatrical productions. It was developed by Adolf Linnebach (1876-1963) around 1917 and was used in North American theatres in the 1920s. Since the middle of the 20th century, it has largely been replaced by other projection technologies.
A holographic screen is a two-dimensional display technology that uses coated glass media for the projection surface of a video projector. "Holographic" refers not to a stereoscopic effect, but to the coating that bundles light using formed microlenses. The lens design and attributes match the holographic area. The lenses may appear similar to the Fresnel lenses used in overhead projectors. The resulting effect is that of a free-space display, because the image carrier appears very transparent. Additionally, the beam manipulation by the lenses can be used to make the image appear to be floating in front of or behind the glass, rather than directly on it. However, this display is only two-dimensional and not true three-dimensional. It is unclear if such a technology will be able to provide acceptable three-dimensional images in the future.
A projector or image projector is an optical device that projects an image onto a surface, commonly a projection screen. Most projectors create an image by shining a light through a small transparent lens, but some newer types of projectors can project the image directly, by using lasers. A virtual retinal display, or retinal projector, is a projector that projects an image directly on the retina instead of using an external projection screen.
