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Screen-door Effect
The screen-door effect (SDE) is a visual artifact of displays, where the fine lines separating pixels (or subpixels) become visible in the displayed image. This can be seen in digital projector images and regular displays under magnification or at close range, but the increases in display resolutions have made this much less significant. More recently, the screen door effect has been an issue with virtual reality headsets and other head-mounted displays, because these are viewed at a much closer distance, and stretch a single display across a much wider field of view. SDE in projectors In LCD and DLP projectors, SDE can be seen because projector optics typically have significantly lower pixel density than the size of the image they project, enlarging these fine lines, which are much smaller than the pixels themselves, to be seen. This results in an image that appears as if viewed through a fine screen or mesh such as those used on anti-insect screen doors. The screen door effe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Screen-door Effect
The screen-door effect (SDE) is a visual artifact of displays, where the fine lines separating pixels (or subpixels) become visible in the displayed image. This can be seen in digital projector images and regular displays under magnification or at close range, but the increases in display resolutions have made this much less significant. More recently, the screen door effect has been an issue with virtual reality headsets and other head-mounted displays, because these are viewed at a much closer distance, and stretch a single display across a much wider field of view. SDE in projectors In LCD and DLP projectors, SDE can be seen because projector optics typically have significantly lower pixel density than the size of the image they project, enlarging these fine lines, which are much smaller than the pixels themselves, to be seen. This results in an image that appears as if viewed through a fine screen or mesh such as those used on anti-insect screen doors. The screen door effe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Screen Door
A screen door can refer to a hinged storm door (cold climates) or hinged screen door (warm climates) covering an exterior door, or a screened sliding door used with sliding glass doors. In any case, the screen door incorporates screen mesh to block birds, flying insects or airborne debris such as seeds or leaves from entering, and pets and small children from exiting interior spaces, while allowing for air, light, and views. History The first screen doors were made using cheesecloth. After the American Civil War, wire cloth was coated with paint and sold for window screens. Construction Aluminium framed Aluminium sliding screen doors are generally constructed by two methods: rollformed or extruded. In both cases the rectangular rollformed or extruded shapes are joined together into a door frame using metal corners or screws. Rollformed The first are rollformed from thin aluminium sheets into a rectangular shaped door frame which incorporates a screen channel to hold the windo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subpixel Rendering
Subpixel rendering is a way to increase the apparent resolution of a computer's liquid crystal display (LCD) or organic light-emitting diode (OLED) display by rendering pixels to take into account the screen type's physical properties. It takes advantage of the fact that each pixel on a color LCD is actually composed of individual red, green, and blue or other color subpixels to anti-alias text with greater detail or to increase the resolution of all image types on layouts which are specifically designed to be compatible with subpixel rendering. Background A single pixel on a color subpixelated display is made of several color primaries, typically three colored elements—ordered (on various displays) either as blue, green, and red (), or as red, green, and blue ( ). Some displays have more than three primaries, often called MultiPrimary, such as the combination of red, green, blue, and yellow (), or red, green, blue and white (W), or even red, green, blue, yellow, and cyan ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scan Line
A scan line (also scanline) is one line, or row, in a raster scanning pattern, such as a line of video on a cathode ray tube (CRT) display of a television set or computer monitor. On CRT screens the horizontal scan lines are visually discernible, even when viewed from a distance, as alternating colored lines and black lines, especially when a progressive scan signal with below maximum vertical resolution is displayed. This is sometimes used today as a visual effect in computer graphics. The term is used, by analogy, for a single row of pixels in a raster graphics image. Scan lines are important in representations of image data, because many image file formats have special rules for data at the end of a scan line. For example, there may be a rule that each scan line starts on a particular boundary (such as a byte or word; see for example BMP file format). This means that even otherwise compatible raster data may need to be analyzed at the level of scan lines in order to convert ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silk Screen Effect
The silk screen effect (SSE) is a visual phenomenon seen in rear-projection televisions. SSE is described by viewers as seeing the texture of the television screen in front of the image. SSE may be found on all rear-projection televisions including DLP and Liquid Crystal on Silicon (LCoS). The effect is most visible when viewing bright white or very light colored images. Viewers also report seeing "sparkles" when viewing very bright colored images. SSE's nomenclature comes from the visual appearance of this effect, which is likened to viewing an image through a silk screen. SSE should not be confused with the screen door effect, another visual phenomenon seen in rear-projection televisions. Cause of SSE SSE is caused by textured screens used in most rear-projection televisions. Rear-projection television manufacturers use textured screens to increase the viewing angle of the television. Reducing SSE SSE can be reduced by properly calibrating the picture controls of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digital Light Processing
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. DLP technology is used in DLP front projectors (standalone projection units for classrooms and business primarily), DLP rear projection television sets, and digital signs. It is also used in about 85% of digital cinema projection, and in additive manufacturing as a light source in some printers to cure resins ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microlens
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. A different type of microlens has two flat and parallel surfaces and the focusing action is obtained by a variation of refractive index across the lens. These are known as gradient-index (GRIN) lenses. Some micro-lenses achieve their focusing action by both a variation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pixelization
Pixelization (British English, pixelisation) or mosaic processing is any technique used in editing images or video, whereby an image is blurred by displaying part or all of it at a markedly lower Image resolution, resolution. It is primarily used for censorship. The effect is a standard graphics filter, available in all but the most basic Raster graphics editor, bitmap graphics editors. As censorship A familiar example of pixelization can be found in majority of television news and documentary productions, in which vehicle license plates and faces of suspects at crime scenes are routinely obscured to maintain the presumption of innocence, such as how it appears in the television series ''Cops (TV series), COPS''. This is especially used in Hungary and Slovakia by RTL Klub. Bystanders and others who do not sign release forms are also customarily pixelized. Footage of nudity (including human male reproductive system, male and human female reproductive system, female genitals, b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pixel Density
Pixels per inch (ppi) and pixels per centimetre (ppcm or pixels/cm) are measurements of the pixel density of an electronic image device, such as a computer monitor or television display, or image digitizing device such as a camera or image scanner. Horizontal and vertical density are usually the same, as most devices have square pixels, but differ on devices that have non-square pixels. Note that pixel density is not the same as where the former describes the amount of detail on a physical surface or device, the latter describes the amount of pixel information regardless of its scale. Considered in another way, a pixel has no inherent size or unit (a pixel is actually a sample), but when it is printed, displayed, or scanned, then the pixel has both a physical size (dimension) and a pixel density (ppi). Basic principles Since most digital hardware devices use dots or pixels, the size of the media (in inches) and the number of pixels (or dots) are directly related by the 'pixels per ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Visual Artifact
Visual artifacts (also artefacts) are artifact (error), anomalies apparent during visual representation as in digital graphics and other forms of imagery, especially photography and microscopy. In digital graphics * Image quality#Image quality factors, Image quality factors, different types of visual artifacts * Compression artifacts * Digital artifacts, visual artifacts resulting from digital image processing * Image noise, Noise * Screen-door effect, also known as fixed-pattern noise (FPN), a visual artifact of digital projection technology *Ghosting (television) *Screen burn-in * Distortion * Silk screen effect * Rainbow effect * Screen tearing * Moiré pattern * Color banding In video entertainment Many people who use their computers as a hobby experience artifacting due to a hardware or software malfunction. The cases can differ but the usual causes are: * Temperature issues, such as failure of cooling fan. * Unsuited video card (graphics card) drivers. * Drivers that have ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Field Of View
The field of view (FoV) is the extent of the observable world that is seen at any given moment. In the case of optical instruments or sensors it is a solid angle through which a detector is sensitive to electromagnetic radiation. Humans and animals In the context of human and primate vision, the term "field of view" is typically only used in the sense of a restriction to what is visible by external apparatus, like when wearing spectacles or virtual reality goggles. Note that eye movements are allowed in the definition but do not change the field of view when understood this way. If the analogy of the eye's retina working as a sensor is drawn upon, the corresponding concept in human (and much of animal vision) is the visual field. It is defined as "the number of degrees of visual angle during stable fixation of the eyes".Strasburger, Hans; Pöppel, Ernst (2002). Visual Field. In G. Adelman & B.H. Smith (Eds): ''Encyclopedia of Neuroscience''; 3rd edition, on CD-ROM. El ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Head-mounted Display
A head-mounted display (HMD) is a display device, worn on the head or as part of a helmet (see Helmet-mounted display for aviation applications), that has a small display optic in front of one (monocular HMD) or each eye ( binocular HMD). An HMD has many uses including gaming, aviation, engineering, and medicine. Virtual reality headsets are HMDs combined with IMUs. There is also an optical head-mounted display (OHMD), which is a wearable display that can reflect projected images and allows a user to see through it. Overview A typical HMD has one or two small displays, with lenses and semi-transparent mirrors embedded in eyeglasses (also termed data glasses), a visor, or a helmet. The display units are miniaturized and may include cathode ray tubes (CRT), liquid-crystal displays (LCDs), liquid crystal on silicon (LCos), or organic light-emitting diodes (OLED). Some vendors employ multiple micro-displays to increase total resolution and field of view. HMDs differ in whethe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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