We present another explanation for the moon illusion, in which the moon looks larger near the horizon than near the zenith. In our model, the sky is considered a spatially contiguous and geometrically smooth surface. When an object (like the moon) breaks the contiguity of the surface, humans perceive an occlusion of the surface rather than an object appearing through a hole. Binocular vision d...

We propose an outdoor photometric stereo method, which considers environmental lighting for improving the performance of surface normal estimation. In the previous methods, the sky illumination effect has been either assumed to be constant throughout the scene, or to be removed by pre-processing. This paper exploits a sky model which can derive the entire sky luminance from a sky zenith image; ...

Computer graphics recently have began being used for visual environmental assessment or architectural designs. Displaying the sky as a background is indispensable in generating photorealistic images for such applications. In this paper, we propose a fast display method of the sky color by expressing the intensity distribution of the sky using basis functions, even if the sun position and/or the...

A new method is presented for retrieval of the aerosol and cloud optical depth using a CCD camera equipped with a fish-eye lens (all-sky imager system). In a first step, the proposed method retrieves the spectral radiance from sky images acquired by the all-sky imager system using a linear pseudoinverse algorithm. Then, the aerosol or cloud optical depth at 500 nm is obtained as that which mini...

[1] Clear-sky longwave radiative feedback processes depicted in climate models prepared for the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4) are investigated using satellite observations of the clear-sky outgoing longwave radiation (OLR). Estimates of clear-sky longwave radiative damping are derived from regional, seasonal, and interannual sources of variabili...

Polarization is the next frontier of CMB analysis, but its signal is dominated over much of the sky by foregrounds which must be carefully removed. To determine the efficacy of this cleaning it is necessary to have sensitive tests for residual foreground contamination in polarization sky maps. The dominant Galactic foregrounds introduce a large-scale anisotropy on to the sky, so it makes sense ...

Measurements of cosmic microwave background (CMB) anisotropies by interferometers offer several advantages over single-dish observations. The formalism for analyzing interferometer CMB data is well developed in the flat-sky approximation, which is valid for small fields of view. As the area of sky is increased to obtain finer spectral resolution, this approximation needs to be relaxed. We exten...

Video content analysis for stilland moving images can be used for various applications, such as high-level semantic-driven operations or pixel-level contentdependent image manipulation. Within video content analysis, sky regions of an image form visually important objects, for which interesting applications at both mentioned levels can be envisaged. This paper introduces a new algorithm and mod...

The scientific productivity of laser guide star adaptive optics systems strongly depends on the sky coverage, which describes the probability of finding natural guide stars for the tip/tilt wavefront sensor(s) to achieve a certain performance. Knowledge of the sky coverage is also important for astronomers planning their observations. In this paper, we present an efficient method to compute the...

I review the development of UV and EUV astronomy, covering the spectral range from 5 to 300 nm, with emphasis on sky surveys for discrete sources. I discuss studies which resulted in lists of sources observed by imaging and deliberately omit most spectroscopic studies. Technical issues, such as detector and telescope developments, are treated separately from descriptions of specific missions an...