:: diffuse reflection constant, the ratio of reflection of the diffuse term of incoming light ( Lambertian reflectance )

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.

In computer graphics, Lambertian reflection is often used as a model for diffuse reflection.

While Lambertian reflectance usually refers to the reflection of light by an object, it can be used to refer to the reflection of any wave.

The emission of a Lambertian radiator does not depend upon the amount of incident radiation, but rather from radiation originating in the emitting body itself.

An EL film is a so-called Lambertian radiator: unlike with neon lamps, filament lamps, or LEDs, the brightness of the surface appears the same from all angles of view ; electroluminescent light is not directional and therefore hard to compare with ( thermal ) light sources measured in lumens or lux.

* For soft indirect illumination, if the surface is Lambertian, then a technique known as irradiance caching may be used to interpolate values from previous calculations.

To calculate the Lambertian ( diffuse ) lighting of a surface, the unit vector from the shading point to the light source is dotted with the unit vector normal to that surface, and the result is the intensity of the light on that surface.

For experimental purposes, a hole in a cavity can be devised to provide a good approximation to a black surface, but will not be perfectly Lambertian, and must be viewed from nearly right angles to get the best properties.

The lightcurve data also suggests that the asteroid is not Lambertian, meaning that surface features, such as shadows from boulders and craters, play a role in the object's perceived brightness and not just the asteroid's relative size when seen from that orientation.

An illuminated ideal diffuse reflecting surface will have equal luminance from all directions in the hemisphere surrounding the surface ( Lambertian reflectance ).

BRDFs can be measured directly from real objects using calibrated cameras and lightsources ; however, many phenomenological and analytic models have been proposed including the Lambertian reflectance model frequently assumed in computer graphics.

Exceptions are Lambertian surfaces, which scatter radiation in all directions according to a cosine function, so their albedo does not depend on the incident distribution.

Such surfaces are said to be Lambertian.

Not all rough surfaces are Lambertian reflectors, but this is often a good approximation when the characteristics of the surface are unknown.

* Lambertian model, representing perfectly diffuse ( matte ) surfaces by a constant BRDF.

This forced all surfaces to be Lambertian, or " perfectly diffuse ".

For example, in ultrasound imaging, " rough " tissues are said to exhibit Lambertian reflectance.

As radiators, a spherical black body is both, a flat black body is Lambertian but not isotropic, a flat chrome sheet is neither, and by symmetry the Sun is isotropic, but not Lambertian on account of limb darkening.

Unfinished wood exhibits roughly Lambertian reflectance, but wood finished with a glossy coat of polyurethane does not, since the glossy coating creates specular highlights.

A surface which obeys Lambert's law is said to be Lambertian, and exhibits Lambertian reflectance.

For example, if the moon were a Lambertian scatterer, one would expect to see its scattered brightness appreciably diminish towards the terminator due to the increased angle at which sunlight hit the surface.

Lambertian reflectance is the property that defines an ideal diffusely reflecting surface.

The luminance of a perfect Lambertian diffuse reflecting surface in foot-lamberts is equal to the incident illuminance in foot-candles.

The fact that it does not diminish illustrates that the moon is not a Lambertian scatterer, and in fact tends to scatter more light into the oblique angles than would a Lambertian scatterer.

The fact that the sun exhibits limb darkening in the visible region illustrates that it is not a Lambertian radiator.

A black body is an example of a Lambertian radiator.

For the special case of a Lambertian source, L is constant such that is proportional to cos θ.

* Lambertian Emitter-a light source whose radiance is according to Lambert's cosine law.

Lambertian reflectance is named after Johann Heinrich Lambert.

Spectralon is a material which is designed to exhibit an almost perfect Lambertian reflectance.

A Lambertian scatterer will then scatter this light according to the same cosine law as a Lambertian emitter.

For example, if the sun were a Lambertian radiator, one would expect to see a constant brightness across the entire solar disc.

Dull ( or earthy ) minerals exhibit little to no lustre, due to coarse granulations which scatter light in all directions, approximating a Lambertian reflector.

We may thus trace the notion of individual autonomy from its manifestation in religious practice and theological reflection through practical politics and political theory into literature and the arts.

This is a phenomenon familiar to all radio listeners, resulting from reflection of skywave signals at night from the ionized layer in the upper atmosphere known as the ionosphere.

The reflection of radiation originating from the anode holder and reflected back to it by the surrounding metal surfaces should also be small because of the peculiar characteristic of the metal surfaces and of the specific geometry.

A sufficiently good approximation for determining the end reflection losses R can be obtained from the angle independent Fresnel formula: Af.

He saw himself in a superior reflection, and he was as a speeding arrow from the taut bow, hurtling with a mad grace, his maleness shining and scented with meadow rue.

Albedo (), or reflection coefficient, derived from Latin albedo " whiteness " ( or reflected sunlight ), in turn from albus " white ", is the diffuse reflectivity or reflecting power of a surface.

Being a dimensionless fraction, it may also be expressed as a percentage, and is measured on a scale from zero for no reflecting power of a perfectly black surface, to 1 for perfect reflection of a white surface.

Every line of written text is a mere reflection of references from any of a multitude of traditions, or, as Barthes puts it, " the text is a tissue of quotations drawn from the innumerable centres of culture "; it is never original.

We seem to see things coming into being and passing from it ; but reflection tells us that decease and growth only mean a new aggregation ( synkrisis ) and disruption ( diakrisis ).

Chapters 1: 1-2: 5 are thus a confession of failure ; chapters 2: 6-3: 6 are a major summary and reflection from the Deuteronomists, setting out the over all formula which the stories in the main text will follow: Israel " does evil in the eyes of Yahweh ;" the people are given into the hands of their enemies and cry out to Yahweh ; Yahweh raises up a leader ; the " spirit of Yahweh " comes upon the leader, the enemy is defeated, and peace is regained.

The energy gap is most directly observed in tunneling experiments and in reflection of microwaves from superconductors.

Jefferson's music is uninhibited and represented the classic sounds of everyday life from a honky-tonk to a country picnic to street corner blues to work in the burgeoning oil fields, a reflection too of his interest in mechanical things.

The view of the Church is that celibacy is a reflection of life in Heaven, a source of detachment from the material world which aids in one's relationship with God.

Therefore, four loose families of more-efficient light transport modelling techniques have emerged: rasterization, including scanline rendering, geometrically projects objects in the scene to an image plane, without advanced optical effects ; ray casting considers the scene as observed from a specific point-of-view, calculating the observed image based only on geometry and very basic optical laws of reflection intensity, and perhaps using Monte Carlo techniques to reduce artifacts ; and ray tracing is similar to ray casting, but employs more advanced optical simulation, and usually uses Monte Carlo techniques to obtain more realistic results at a speed that is often orders of magnitude slower.

The reflected light being the sum of the incoming light ( L < sub > i </ sub >) from all directions, multiplied by the surface reflection and incoming angle.

( That said, scientists have had some success focusing X-rays with microscopic Fresnel zone plates made from gold, and by critical-angle reflection inside long tapered capillaries.

Sharp features in the diffraction pattern arise from periodic, repeating structure in the sample, which are often very strong due to coherent reflection of many photons from many regularly spaced instances of similar structure, while non-periodic components of the structure result in diffuse ( and usually weak ) diffraction features.

Following Bragg's law, each dot ( or reflection ), in this diffraction pattern forms from the constructive interference of X-rays passing through a crystal.

This is also the title given in the Bible to Eve, the Hebrew Khavvah ( חוה ), the Aramaic Hawwah, who was made from the rib of Adam, in a strange reflection of the Sumerian myth, in which Adam — not Enki — walks in the Garden of Paradise.

Partial transmission and reflection amplitudes of a wave travelling from a low to high refractive index medium.

Note that reflection by a window is from the front side as well as the back side, and that some of the light bounces back and forth a number of times between the two sides.