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...

Computing global illumination in complex scenes is even with todays computational power a demanding task. In this work we propose a novel irradiance caching scheme that combines the advantages of two state-of-the-art algorithms for high-quality global illumination rendering: lightcuts, an adaptive and hierarchical instant-radiosity based algorithm and the widely used (ir)radiance caching algori...

We describe an aircraft-based Fourier-transform spectrometer (FTS) designed to measure the Earth outgoing radiance spectrum in the far-infrared-submillimeter spectral range. The instrument features include a rapid-scan FTS to obtain high spatial resolution from a moving aircraft platform, a sensitive two-channel detector, and a CCD camera for recording the nadir cloud scene with each scan recor...

Ray tracing, which computes radiance, is usually regarded as an off-line rendering algorithm that is too slow for interactive use. In this paper, we present a system that uses per-surface four-dimensional interpolants to approximate radiance, while providing guaranteed error bounds. Our system exploits object-space, ray-space, image-space and temporal coherence to accelerate ray tracing. Our sy...

[1] The ARM Shortwave Spectrometer (SWS) measures zenith radiance at 418 wavelengths between 350 and 2170 nm. Because of its 1-sec sampling resolution, the SWS provides a unique capability to study the transition zone between cloudy and clear sky areas. A spectral invariant behavior is found between ratios of zenith radiance spectra during the transition from cloudy to cloud-free. This behavior...

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...

The QUick Image Display (QUID) model accurately computes and displays radiance images of aircraft and other objects, generically called targets, at animation rates while the target undergoes unrestricted flight. Animation rates are obtained without sacrificing radiometric accuracy by using two important innovations. First, QUID has been implemented using the Open Scene Graph (OSG) library, an o...

The Radiance Enhancement (RE) method was introduced for efficient detection of clouds from the space. Recently, we have also reported that due to high reflectance combustion-originated smokes, this approach can be generalized forest fires by retrieving and analyzing datasets collected a space orbiting micro-spectrometer operating in near infrared spectral range. In our previous publication, per...