• Corpus ID: 9303910

Why is snow so bright ?

  title={Why is snow so bright ?},
  author={J. J.},
  • J. J.
  • Published 1992
  • Physics
Snow seen against an overcast sky typically appears much brighter than the clouds that provide the illumination. This raises the problem of how a reflecting surface may appear brighter than its diffuse illuminant. We show that three factors are largely responsible for this visually striking effect: the law of darkening for the cloud cover, the reflectivity of the snow and the average landscape albedo, and the observer's contrast sensitivity function. Thus the explanation is of a curiously mixed… 

Vision in bad weather

  • S. NayarS. Narasimhan
  • Environmental Science
    Proceedings of the Seventh IEEE International Conference on Computer Vision
  • 1999
This work begins by studying the visual manifestations of different weather conditions, and develops models and methods for recovering pertinent scene properties, such as three-dimensional structure, from images taken under poor weather conditions.

Vision and the weather

This work begins by studying the visual manifestations of different weather conditions, and draws on what is already known about atmospheric optics to identify effects caused by bad weather that can be turned to the authors' advantage.

Vision and the Atmosphere

This work studies the visual manifestations of different weather conditions, and model the chromatic effects of the atmospheric scattering and verify it for fog and haze, and derives several geometric constraints on scene color changes caused by varying atmospheric conditions.

Models and algorithms for vision through the atmosphere

This thesis presents a novel and comprehensive set of models, algorithms and image datasets for better image understanding in bad weather, and presents an analytic model for multiple scattering of light in a scattering medium.

Validation of an Analytical Snow BRDF Model Using PARASOL Multi-Angular and Multispectral Observations

A two-parameter model for the reflectance of snow and test it against multispectral and multi-angular observations, which reproduces the main features of the snow angular reflectance.

Shape-from-shading on a cloudy day

In the classical shape-from-shading model, surface luminance depends primarily on the unit surface normal. However, under diffuse lighting conditions, such as the sky on a cloudy day, luminance

A ray-based computational model of light sources and illumination

  • M. LangerS. Zucker
  • Physics
    Proceedings of the Workshop on Physics-Based Modeling in Computer Vision
  • 1995
Models of light sources and illumination are fun­ damental in physics-based vision. Light sources have traditionally been modelled as objects that emit light, while illumination has been modelled as

Exploratory Vision

This paper describes highlights in the nearly century and a half long history of continuous research on the role of retinal image motion in limiting or influencing visual acuity. This review is

Reflection and transparency model of rose petals for computer graphics based on the micro-scopic scale structures

A reflection and transparency model of rose petals for photorealistic computer graphics based on its microscopic scale structures, such as the dome-shaped and translucent cells is described.



Optical Properties of Snow

Measurements of the dependence of snow albedo on wavelength, zenith angle, grain size, impurity content, and cloud cover can be interpreted in terms of single-scattering and multiple-scattering

The spectral bidirectional reflectance of snow

A radiative transfer model for the bidirectional reflectance-distribution function (BRDF) shows that snow is moderately anisotropic in the near-infrared wavelengths. Although the

Calculating the reflectance map.

The reflectance map is derived in terms of the bidirectional reflectance-distribution function (BRDF) and the distribution of source radiance in order to improve the understanding of image formation.

Light scattering in planetary atmospheres

This paper reviews scattering theory required for analysis of light reflected by planetary atmospheres. Section 1 defines the radiative quantities which are observed. Section 2 demonstrates the

Brightness variations in stimuli with ramp-like contours.

  • J. P. Thomas
  • Psychology
    Journal of the Optical Society of America
  • 1966
Perceived brightness was measured at several points on stimuli bounded by luminance ramps. As the ramps widen, the perceived contrast between stimulus and background decreases, although objective

Sine-wave response of the visual system. I. The Mach phenomenon.

A visual slit photometer has been built with which the subjective intensity distribution may be evaluated directly and the objective and subjective intensity distributions have been combined to yield the sine-wave response of the visual system.

Visual perception.

  • R. Haber
  • Psychology, Art
    Annual review of psychology
  • 1978
Although the majority of children successfully develop the ability to focus visually and to make fine discriminations in visual materials during the primary years, some will be well into the intermediate grades before these skills are adequately developed for visual learning tasks.

Contour Perception, Illusion and Reality*

A qualitative analysis of the perception of contours indicates that, to counteract the filtering characteristics of the eye, there may be a process of contour enhancement by a second difference

Visibility of low-spatial-frequency sine-wave targets: Dependence on number of cycles.

The results suggest that the low-frequency decrease in reported MTF's is due to the decrease of the number of cycles used in determining them.