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C
Published in Philip A. Laplante, Comprehensive Dictionary of Electrical Engineering, 2018
capability diagram and functional characteristics of the instrument modules. camera a device for acquiring an image, usually in a photographic or electronic form -- in the latter case typically as a TV camera. Cameras may operate in optical, infra red or other wavelength bands. camera calibration a process in which certain camera parameters, or equivalently some quantities which are required for determination of the perspective projection on an image plane of a point in the 3-D world, are calculated by using the known correspondence between some points in the 3-D world and their images in the image plane. camera model (1) the representation of the geometric and physical features of a stereovision system, with relative references between the two camera coordinate systems, and absolute references to a fixed coordinate system. (2) a mathematical model by which the perspective projection on an image plane of a point in the 3-D world can be determined. can slang for a pole-top distribution transformer. candela (cd) unit of measurement for luminous intensity (illuminating power in lumens/sr). The luminous intensity of 1/60 of 1 cm2 of projected area of a blackbody radiator operating at the temperature of solidification of platinum (2046K). Historically, the unit of measurement for the light emitted by one flame of a specified make of candle. candle See candela. See candela. intensity of a lamp or luminaire in a plane through the light center. canned magnet a magnet that is completely encased in its own vacuum jacket. Canny edge detector See Canny Operator.
Design of Traffic Signs*
Published in Cándida Castro, Tim Horberry, The Human Factors of Transport Signs, 2004
The luminous flux is the light emitted by a lantern or received by a surface such as a sign face. It is measured in lumen (lm), which is a power-related unit. The light emitted by a point source (such as a lantern) per solid angle (steradian) is called luminous intensity and is a power-density term. Its unit is the candela (cd), one of the seven basic units of the SI system. Luminance is the luminous intensity per unit area reflected in a given direction from a point on a lit surface. Its units are candela per unit area, i.e., cd/m2, and it measures the light reflected from a surface. The subjective equivalent of luminance is brightness (Lay, 1998, Chap. 24).
The Visual Environment: Measurement and Design
Published in R. S. Bridger, Introduction to Human Factors and Ergonomics, 2017
The SI unit of luminous intensity is the candela (cd). An imaginary point source of luminous intensity 1 cd will emit light in all directions. A source of greater intensity will emit more light. In both cases, we can imagine a sphere of light spreading out from the source. Clearly, the intensity of the source itself does not depend on the distance from which it is viewed. However, the strength of the light at the edges of the imaginary sphere will depend on viewing distance.
Improving illuminance performance by implementing a kinetic façade system: case study of office building in Dubai
Published in Journal of Asian Architecture and Building Engineering, 2023
Luminance is a photometric measure of the luminous intensity per unit area of light travelling in a given direction. It describes the amount of light that passes through, is emitted, or is reflected from, a particular area, and falls within a given solid angle. Selected for this purpose are the lux performance on 15th August at 9:00 am from the east direction, 15th March at 5:00 pm from a west direction, and 15th January at 1:00 pm from a south direction. Table 8 presents the results in terms of luminous intensity performance with the cd/m2 units. Based on the Table 8, the luminance value reduced especially at 9:00 am and 1:00 pm, this minimised the variation which indicates low contrast and helped to achieved uniformity ratio of light distribution which also indicates better visual comfort. Studies (Suk 2019) stated that for the background lighting on the walls the maximum luminance should be limited to 1000 cd/m2 a luminance on the ceiling of 250–500 lux is perceived as comfortable, this means the kinetic case is much better than the base case.
Thermal Analysis of Light Source for Optogenetics Experiments
Published in IETE Journal of Research, 2020
Rabinder Henry, Velmathi Guruviah
Luminous intensity (cd) is the measure of luminous flux per solid angle which is measured in the direction of light emitted in terms of light power averaged over emitted wavelength. The measured luminous intensity is shown in Figure 27.