Recent developments in integrated circuit technology tend toward increased numbers of cores rather than faster clock speeds, so software must use parallelism to achieve faster run times. The ray tracing performed by Radiance is highly parallelizable in concept, with the exception of irradiance caching that serially stores and retrieves results of expensive indirect irradiation computations. Thi...

Correlated pairs of photons can be used to access what is effectively an omnipresent absolute standard of spectral radiance. The process of spontaneous parametric downconversion, in which pump photons are converted into pairs of photons, can be thought of as being stimulated by an omnipresent and omnidirectional one photon per mode vacuum background. This background has units of spectral radian...

The upwelling radiance distribution in optically shallow water is investigated with experiments and Hydrolight numerical simulations for two different benthic surfaces and a range of solar zenith angles (,608). Over a bright sand surface (water depth 5 m) the upwelling radiance distribution was brightest at nadir and decreased toward the horizon. The upwelling radiance distribution was nearly a...

Longwave radiative heat transfer is a key determinant of energy consumption in buildings and view factor calculations are therefore required for the detailed simulation between their environment as well exchange within rooms. Typically, these either derived through analytical means or performed part process. This paper describes methodology employing RADIANCE, command-line open-source raytracin...

A genetic optimization approach has been used for the design of an external shading device in an office with a window and different glass characteristics. The primary energy consumption for heating cooling and lighting have been minimized. Simulations have been performed using the energy code ESP-r and lighting simulation package Radiance, the optimization loop has been driven by the software t...

An experimental investigation of ir sky radiance and radiance fluctuations in the 8-13-micro atmospheric window is reported. Measurements were made with ground-based, filtered bolometer detector radiometers under clear sky and cirrus overcast conditions. Sky radiance was measured very close to the limb of the sun to permit detection of the solar aureole caused by forward scattering by cirrus ic...

Integrating spheres are often used as calibration sources providing uniform radiance within a solid angle and/or uniform irradiance at a distance. The best performance in such a system can be achieved if one is able to evaluate as well as predict the important characteristics of the sphere system’s output, such as the spatial and angular distributions of radiance over the exit port, or the dist...

A laboratory experiment was designed to determine the spectral characteristics of different types of sediment suspended in water in the visible and near infrared wavelengths (0.45-0.9 /xm) using a fourchannel radiometer. Field collected sediments were resuspended in water to produce different concentration levels for the measurement of radiance. Spectral measurements of turbid water showed a di...

Topography affects the fraction of direct and diffuse radiation received on a pixel and changes the sun–target–sensor geometry, resulting in variations in the observed radiance. Retrieval of surface–atmosphere properties from top of atmosphere radiance may need to account for topographic effects. This study investigates how such effects can be taken into account for top of atmosphere radiance m...