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Day And Night Camera
A day and night camera is a security camera that can see the picture during the day hours, when there is enough sunlight, and during the night in total darkness or minimum illumination. A day and night camera has special lenses that allow infrared emission produced by infrared LEDs and reflected from objects to go through and reach a CCD or CMOS chip inside the camera. As a result, the end user can see picture in total darkness at the distance of infrared emission produced by LEDs. A day and night camera can have infrared LEDs mounted on its housing or can accept the emission, produced by an infrared turret. Day and night cameras often have modifications in their digital signal processor (DSP) that compensates for the difference in illumination between day and night modes. HDR technology may also be used in more expensive models to compensate for the difference in illumination between shaded and lighted areas of surveillance. See also * Camera lens A camera lens, photographi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Security Camera
A closed-circuit television camera is a type of surveillance camera that transmits video signals to a specific set of monitors or video recording devices, rather than broadcasting the video over public airwaves. The term "closed-circuit television" indicates that the video feed is only accessible to a limited number of people or devices with authorized access. Cameras can be either analog or digital. Walter Bruch was the inventor of the CCTV camera. Video cameras Video cameras are either analogue or digital, which means that they work on the basis of sending analogue or digital signals to a storage device such as a video tape recorder or desktop computer or laptop computer. Analogue These cameras can record straight to a video tape recorder which can record analogue signals as pictures. If the analogue signals are recorded to tape, then the tape must run at a very slow speed in order to operate continuously. This is because to allow a three-hour tape to run for 24 hours, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Illumination (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 kindled ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Infrared
Infrared (IR; sometimes called infrared light) is electromagnetic radiation (EMR) with wavelengths longer than that of visible light but shorter than microwaves. The infrared spectral band begins with the waves that are just longer than those of red light (the longest waves in the visible spectrum), so IR is invisible to the human eye. IR is generally (according to ISO, CIE) understood to include wavelengths from around to . IR is commonly divided between longer-wavelength thermal IR, emitted from terrestrial sources, and shorter-wavelength IR or near-IR, part of the solar spectrum. Longer IR wavelengths (30–100 μm) are sometimes included as part of the terahertz radiation band. Almost all black-body radiation from objects near room temperature is in the IR band. As a form of EMR, IR carries energy and momentum, exerts radiation pressure, and has properties corresponding to both those of a wave and of a particle, the photon. It was long known that fires e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digital Signal Processor
A digital signal processor (DSP) is a specialized microprocessor chip, with its architecture optimized for the operational needs of digital signal processing. DSPs are fabricated on metal–oxide–semiconductor (MOS) integrated circuit chips. They are widely used in audio signal processing, telecommunications, digital image processing, radar, sonar and speech recognition systems, and in common consumer electronic devices such as mobile phones, disk drives and high-definition television (HDTV) products. The goal of a DSP is usually to measure, filter or compress continuous real-world analog signals. Most general-purpose microprocessors can also execute digital signal processing algorithms successfully, but may not be able to keep up with such processing continuously in real-time. Also, dedicated DSPs usually have better power efficiency, thus they are more suitable in portable devices such as mobile phones because of power consumption constraints. DSPs often use special m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
High Dynamic Range Imaging
High dynamic range (HDR), also known as wide dynamic range, extended dynamic range, or expanded dynamic range, is a signal with a higher dynamic range than usual. The term is often used in discussing the dynamic ranges of images, videos, audio or radio. It may also apply to the means of recording, processing, and reproducing such signals including analog and digitized signals. Imaging In this context, the term ''high dynamic range'' means there is a large amount of variation in light levels within a scene or an image. The ''dynamic range'' refers to the range of luminosity between the brightest area and the darkest area of that scene or image. (HDRI) refers to the set of imaging technologies and techniques that allow the dynamic range of images or videos to be increased. It covers the acquisition, creation, storage, distribution and display of images and videos. Modern films have often been shot with cameras featuring a higher dynamic range, and legacy films can be post-con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Camera Lens
A camera lens, photographic lens or photographic objective is an optical lens (optics), lens or assembly of lenses (compound lens) used in conjunction with a camera body and mechanism to Imaging, make images of objects either on photographic film or on other media capable of storing an image Photosensitivity, chemically or Image sensor, electronically. There is no major difference in principle between a lens used for a still camera, a video camera, a telescope, a microscope, or other apparatus, but the details of design and construction are different. A lens might be permanently fixed to a camera, or it might be interchangeable lens camera, interchangeable with lenses of different focal lengths, apertures, and other properties. While in principle a simple lens, simple convex lens will suffice, in practice a compound lens made up of a number of optical lens elements is required to correct (as much as possible) the many optical aberrations that arise. Some aberrations will be prese ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
