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The luminance of a perfect Lambertian diffuse reflecting surface in foot-lamberts is equal to the incident illuminance in foot-candles.
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luminance and perfect
Lambertian reflection from polished surfaces are typically accompanied by specular reflection ( gloss ), where the surface luminance is highest when the observer is situated at the perfect reflection direction ( i. e. where the direction of the reflected light is a reflection of the direction of the incident light in the surface ), and falls off sharply.
luminance and Lambertian
One common model for diffuse reflection is Lambertian reflectance, in which the light is reflected with equal luminance ( in photometry ) or radiance ( in radiometry ) in all directions, as defined by Lambert's cosine law.
An illuminated ideal diffuse reflecting surface will have equal luminance from all directions in the hemisphere surrounding the surface ( Lambertian reflectance ).
luminance and diffuse
Many diffuse reflectors are described or can be approximated by Lambert's cosine law, which describes surfaces that have equal luminance when viewed from any angle.
For real diffuse reflectors, the ratio of luminance to illuminance in these units is roughly equal to the reflectance of the surface.
luminance and reflecting
How much the room light reduces the contrast ratio depends on the luminance of the display, as well as the amount of light reflecting off the display.
luminance and surface
The luminance indicates how much luminous power will be detected by an eye looking at the surface from a particular angle of view.
Subsequently, the video head erases and re-records the video signal ( combined luminance and color signal ) over the same tape surface, but the video signal's higher center frequency results in a shallower magnetization of the tape, allowing both the video and residual AFM audio signal to coexist on tape.
Cells in the retina, the lateral ginculate body or relay station in the brain, and in the visual cortex respond predominantly to step changes in luminance rather than homogeneous surface colors.
However, radiosity equivocates the illuminance falling on a surface with the luminance that leaves the surface.
Importance Sampling is a technique which is motivated to cast less rays through the scene while still converging correctly to outgoing luminance on the surface point.
luminance and foot-lamberts
: is the luminance, in foot-lamberts,
The Society of Motion Picture and Television Engineers ( SMPTE ) recommended, in SMPTE 196M, a screen luminance of 16 foot-lamberts for commercial movie theaters, " open-gate " with no film in the projector.
luminance and is
As it passes each point the intensity of the beam is varied, varying the luminance of that point.
When analog television was developed, no affordable technology for storing any video signals existed ; the luminance signal has to be generated and transmitted at the same time at which it is displayed on the CRT.
The video carrier is demodulated to give a composite video signal ; this contains luminance, chrominance and synchronization signals ; this is identical to the video signal format used by analog video devices such as VCRs or CCTV cameras.
The compromise can improve text appearance when luminance detail is more important than chrominance.
For example, the human eye is more sensitive to subtle variations in luminance than it is to variations in color.
* the power by which the luminance of an image is increased in gamma correction
Another use is for backward compatibility and graceful degradation: in color television, encoding color via a luminance-chrominance transform domain ( such as YUV ) means that black-and-white sets display the luminance, while ignoring the color information.
The SI unit for luminance is candela per square metre ( cd / m < sup > 2 </ sup >).
The CGS unit of luminance is the stilb, which is equal to one candela per square centimetre or 10 kcd / m < sup > 2 </ sup >.
This means that for an ideal optical system, the luminance at the output is the same as the input luminance.
For real, passive, optical systems, the output luminance is at most equal to the input.
The light at the image plane, however, fills a larger solid angle so the luminance comes out to be the same assuming there is no loss at the lens.
: is the luminance ( cd / m < sup > 2 </ sup >),
One application is to formulas for washing and conditioning grey or blonde hair, where the brightener can not only increase the luminance and sparkle of the hair, but can also correct dull, yellowish discoloration without darkening the hair.
In a Bayer filter arrangement, green is given twice as many detectors as red and blue ( ratio 1: 2: 1 ) in order to achieve higher luminance resolution than chrominance resolution.
The color information is called chrominance or C for short, while the black and white information is called the luminance or Y for short.
The color space is three dimensional by the nature of the human vision, so after subtracting the luminance, which is carried by the base signal, the color sub carrier still has to carry a two dimensional signal.
Typically the red ( R ) and the blue ( B ) information are carried because their signal difference with luminance ( R-Y and B-Y ) is stronger than that of green ( G-Y ).
Fortunately, the human visual system is similar in design: it perceives changes in luminance at a higher resolution than changes in chrominance, so this asymmetry has minimal visual impact.
luminance and equal
With this nonlinear relationship, equal steps in encoded luminance correspond roughly to subjectively equal steps in brightness.
8 ) converted the task of detecting fringe shifts from the relatively insensitive one of estimating their lateral displacements to the considerably more sensitive task of adjusting the light intensity on both sides of a sharp boundary for equal luminance.
Eads ( 2000 ) proposed a revised APEX in which luminance value was equal to EV for ISO 100 speed, but he did not use the term light value.
In APEX, luminance value and incident light value are numerically equal, so that for a given “ light value ”, either meaning 2 or 3 would result in the same camera settings.
To encode grayscale intensity in RGB, each of the three primaries can be set to equal the calculated luminance.
The opposing gradients will eventually come to a point where there is an equal degree of luminance of the object and the background.
Taken further, since 537. 6 lines is equal to 268. 8 cycles, and given 576i50 has an active line period of 52µs, its luminance signal requires a bandwidth of 268. 8 / 52 = 5. 17 MHz.
luminance and illuminance
The field of optical photometry uses a different set of distinctions, the main ones being luminance and illuminance.
The 200 mm lens's 4 opening is larger than that of the 100 mm lens but, given the same light transmission efficiency, both will produce the same illuminance in the focal plane when imaging an object of a given luminance.
For example, daylight at a color temperature of 6500 K and an illuminance of 10 < sup > 4 </ sup > to 10 < sup > 5 </ sup > lux results in natural color rendition, but the same color temperature would appear bluish under low luminance.
The illuminance E < sub > v </ sub > is controlled by the < var > f </ var >- number but also depends on the scene luminance L < sub > v </ sub >.
Stroebel, Compton, Current, and Zakia ( 2000 ) referred to “ scene illuminance ” in the text of the article, but the example used units of luminance.
The exposure time is the same for all elements, but the image illuminance varies with the luminance of each subject element.
0.273 seconds.