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Temporal Light Effects
Temporal light effects (TLEs) is the general term for all possible effects resulting from temporal light modulations (TLMs). Root cause Light emitted from lighting equipment such as luminaires and lamps may vary in strength as function of time, either intentionally or unintentionally. Intentional light variations are applied amongst others for warning, signalling (e.g. traffic-light signalling, flashing aviation light signals), entertainment (like stage lighting), metrology (strobe light for measurement of rotation speed), navigation (like optical beacons, lighthouses) or for communication (Li-Fi). Generally, the light output of lighting equipment may also have unintentional light level modulations due to the lighting equipment itself. The magnitude, shape, periodicity and frequency of the TLM will depend on many factors such as the type of light source, the electrical mains-supply frequency, the driver or ballast technology and type of light regulation technology applied (e.g. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lighting
Lighting or illumination is the deliberate use of light to achieve practical or aesthetic effects. Lighting includes the use of both artificial light sources like lamps and light fixtures, as well as natural illumination by capturing daylight. Daylighting (using windows, skylights, or light shelves) is sometimes used as the main source of light during daytime in buildings. This can save energy in place of using artificial lighting, which represents a major component of energy consumption in buildings. Proper lighting can enhance task performance, improve the appearance of an area, or have positive psychological effects on occupants. Indoor lighting is usually accomplished using light fixtures, and is a key part of interior design. Lighting can also be an intrinsic component of landscape projects. History With the discovery of fire, the earliest form of artificial lighting used to illuminate an area were campfires or torches. As early as 400,000 years ago, fire was kindl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stroboscopic Effect
The stroboscopic effect is a visual phenomenon caused by aliasing that occurs when continuous rotational or other cyclic motion is represented by a series of short or instantaneous samples (as opposed to a continuous view) at a sampling rate close to the period of the motion. It accounts for the "wagon-wheel effect", so-called because in video, spoked wheels (such as on horse-drawn wagons) sometimes appear to be turning backwards. A strobe fountain, a stream of water droplets falling at regular intervals lit with a strobe light, is an example of the stroboscopic effect being applied to a cyclic motion that is not rotational. When viewed under normal light, this is a normal water fountain. When viewed under a strobe light with its frequency tuned to the rate at which the droplets fall, the droplets appear to be suspended in mid-air. Adjusting the strobe frequency can make the droplets seemingly move slowly up or down. Stroboscopic principles, and their ability to create an illusio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Film And Video Technology
A film also called a movie, motion picture, moving picture, picture, photoplay or (slang) flick is a work of visual art that simulates experiences and otherwise communicates ideas, stories, perceptions, feelings, beauty, or atmosphere through the use of moving images. These images are generally accompanied by sound and, more rarely, other sensory stimulations. The word "cinema", short for cinematography, is often used to refer to filmmaking and the film industry, and to the art form that is the result of it. Recording and transmission of film The moving images of a film are created by photographing actual scenes with a motion-picture camera, by photographing drawings or miniature models using traditional animation techniques, by means of CGI and computer animation, or by a combination of some or all of these techniques, and other visual effects. Before the introduction of digital production, series of still images were recorded on a strip of chemically sensitize ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Power-line Flicker
Power-line flicker is a visible change in brightness of a lamp due to rapid fluctuations in the voltage of the power supply. The voltage drop is generated over the source impedance of the grid by the changing load current of an equipment or facility. These fluctuations in time generate flicker. The effects can range from disturbance to epileptic attacks of photosensitive persons. Flicker may also affect sensitive electronic equipment such as television receivers or industrial processes relying on constant electrical power. Causes Flicker may be produced, for example, if a steel mill uses large electric motors or arc furnaces on a distribution network, or frequent starting of an elevator motor in an office building, or if a rural residence has a large water pump starting regularly on a long feeder system. The likelihood of flicker increase as the size of the changing load becomes larger with respect to the prospective short-circuit current available at the point of common connectio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stroboscopic Effect
The stroboscopic effect is a visual phenomenon caused by aliasing that occurs when continuous rotational or other cyclic motion is represented by a series of short or instantaneous samples (as opposed to a continuous view) at a sampling rate close to the period of the motion. It accounts for the "wagon-wheel effect", so-called because in video, spoked wheels (such as on horse-drawn wagons) sometimes appear to be turning backwards. A strobe fountain, a stream of water droplets falling at regular intervals lit with a strobe light, is an example of the stroboscopic effect being applied to a cyclic motion that is not rotational. When viewed under normal light, this is a normal water fountain. When viewed under a strobe light with its frequency tuned to the rate at which the droplets fall, the droplets appear to be suspended in mid-air. Adjusting the strobe frequency can make the droplets seemingly move slowly up or down. Stroboscopic principles, and their ability to create an illusio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Temporal Light Interference
Temporal light interference (TLI) is an unacceptable degradation of the performance of an equipment or system that has an optical input for its intended functioning and is caused by a temporal light modulation disturbance. A temporal light modulation (TLM) disturbance may be either an intentional or unintentional temporal light modulation (TLM) of lighting equipment such as luminaires or lamps. Examples of equipment that can be interfered are barcode scanners, cameras and test equipment. NOTE – Temporal light modulations may also annoy human beings. In general, undesired effects in the visual perception of a human observer induced by light intensity fluctuations are called Temporal Light Artefacts (TLAs). Root causes of TLI Temporal light modulation disturbances may arise from fluctuations of the light intensity of lighting equipment. Light emitted from lighting equipment such as luminaires and lamps may vary in strength as function of time, either intentionally or unintention ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Temporal Light Artefacts
Temporal Light Artefacts (TLAs) are undesired effects in the visual perception of a human observer induced by temporal light modulations. Two well-known examples of such unwanted effects are flicker and stroboscopic effect. The term 'flicker' refers to directly visible light modulations at relatively low frequencies (80 Hz) and larger modulation levels. __TOC__ Relevance Various scientific committees have assessed the potential health, performance and safety-related aspects resulting from temporal light modulations. TLAs must be limited to certain levels to avoid annoyance due to the direct visibility by humans and to prevent potential health issues. After longer exposure, TLAs may reduce task performance and cause fatigue. Possible health effects for specific persons are photosensitive epileptic seizure, migraine and aggravation of autistic behavior. The incorrect perception of the motion of an object due to stroboscopic effect may be unacceptable in working environments wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Temporal Light Interference
Temporal light interference (TLI) is an unacceptable degradation of the performance of an equipment or system that has an optical input for its intended functioning and is caused by a temporal light modulation disturbance. A temporal light modulation (TLM) disturbance may be either an intentional or unintentional temporal light modulation (TLM) of lighting equipment such as luminaires or lamps. Examples of equipment that can be interfered are barcode scanners, cameras and test equipment. NOTE – Temporal light modulations may also annoy human beings. In general, undesired effects in the visual perception of a human observer induced by light intensity fluctuations are called Temporal Light Artefacts (TLAs). Root causes of TLI Temporal light modulation disturbances may arise from fluctuations of the light intensity of lighting equipment. Light emitted from lighting equipment such as luminaires and lamps may vary in strength as function of time, either intentionally or unintention ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photosensitive Epilepsy
Photosensitive epilepsy (PSE) is a form of epilepsy in which seizures are triggered by visual stimuli that form patterns in time or space, such as flashing lights; bold, regular patterns; or regular moving patterns. PSE affects approximately one in 4,000 people (5% of those with epilepsy). Signs and symptoms People with PSE experience epileptiform seizures upon exposure to certain visual stimuli. The exact nature of the stimulus or stimuli that triggers the seizures varies from one patient to another, as does the nature and severity of the resulting seizures (ranging from brief absence seizures to full tonic–clonic seizures). Many PSE patients experience an " aura" or feel odd sensations before the seizure occurs, and this can serve as a warning to a patient to move away from the trigger stimulus. The visual trigger for a seizure is generally cyclic, forming a regular pattern in time or space. Flashing lights or rapidly changing or alternating images (as in clubs, around ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Temporal Light Artefacts
Temporal Light Artefacts (TLAs) are undesired effects in the visual perception of a human observer induced by temporal light modulations. Two well-known examples of such unwanted effects are flicker and stroboscopic effect. The term 'flicker' refers to directly visible light modulations at relatively low frequencies (80 Hz) and larger modulation levels. __TOC__ Relevance Various scientific committees have assessed the potential health, performance and safety-related aspects resulting from temporal light modulations. TLAs must be limited to certain levels to avoid annoyance due to the direct visibility by humans and to prevent potential health issues. After longer exposure, TLAs may reduce task performance and cause fatigue. Possible health effects for specific persons are photosensitive epileptic seizure, migraine and aggravation of autistic behavior. The incorrect perception of the motion of an object due to stroboscopic effect may be unacceptable in working environments wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Traffic-light Signalling And Operation
In traffic engineering, there are regional and national variations in traffic light operation. This may be in the standard traffic light sequence (such as the inclusion of a red-amber phase) or by the use of special signals (such as flashing amber or public transport signals). Flashing signals Flashing red In the United States and Canada, a flashing red light is the equivalent of a stop sign. In New Zealand, Hong Kong and the United Kingdom, paired red/red traffic lights are often installed outside fire and ambulance stations on major roads, which, when activated by the station, flash alternatively (so that at any time one red light is always showing), the purpose being to cause traffic to stop for a set amount of time to allow emergency vehicles to exit their station safely. The UK also uses an amber light which precedes the flashing red lights, and these signals are also used at level crossings, airfields and lifting bridges. Flashing amber/yellow In the US, Canada, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
