[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...

Atmospheric profile variability impacts the effectiveness of hyperspectral remote sensing systems to identify geological materials from space. This variability alters the "truth" spectrum (e.g. reflective or emissive) by modifying its spectrum through such atmospheric factors as transmissivity, upwelling radiance, and downwelling radiance. Incomplete characterization of these effects can lead t...

In this case report the diagnosis of a uterine lipoleiomyoma is depicted by means of a three-dimensional radiance mode. The advent of radiance or silhouette mode as a new tool in ultrasound diagnosis is intended to assist by generating additional realistic image visualization and a better distinction among different tissues.

ii Abstract (in Finnish) iiiin Finnish) iii

In 1900, Max Planck developed the modern theory describing the radiation field of a blackbody. At the time, there were two distinct models for blackbody radiation: the Rayleigh-Jeans law, which fit the measurements well at low frequencies, and Wien’s law, which worked well at high frequencies, but neither worked everywhere. Planck, by making the ingenious assumption that the energy of the modes...

The incident indirect light over a range of image pixels is often coherent. Two common approaches to exploit this inter-pixel coherence to improve rendering performance are Irradiance Caching and Radiance Caching. Both compute incident indirect light only for a small subset of pixels (the cache), and later interpolate between pixels. Irradiance Caching uses scalar values that can be interpolate...

A primary impact of urbanization on the local climate is evident in the phenomenon recognized as the Urban Heat Island (UHI) effect. This urban thermal anomaly can increase the health risks of vulnerable populations to heat waves. The surface UHI results from emittance in the longer wavelengths of the thermal infrared; however, there are also urban anomalies that are detectable from radiance in...

Architectural walkthroughs require fast global illumination algorithms and also accurate results from certain viewpoints. This paper introduces a global illumination method that combines several strategies to meet the contradicting criteria of architectural walkthroughs. The methods include parallel and perspective ray-bundle shooting and ray shooting. Each method is designed to randomly approx...