5,403 research outputs found
Blind Detection and Compensation of Camera Lens Geometric Distortions
This paper presents a blind detection and compensation technique for camera
lens geometric distortions. The lens distortion introduces higher-order
correlations in the frequency domain and in turn it can be detected using
higher-order spectral analysis tools without assuming any specific calibration
target. The existing blind lens distortion removal method only considered a
single-coefficient radial distortion model. In this paper, two coefficients are
considered to model approximately the geometric distortion. All the models
considered have analytical closed-form inverse formulae.Comment: 6 pages, 4 figures, 2 table
Experimental investigation on performance of fabrics for indirect evaporative cooling applications
Β© 2016 Indirect evaporative cooling, by using water evaporation to absorb heat to lower the air temperature without adding moisture, is an extremely low energy and environmentally friendly cooling principle. The properties of the wet channel surface in an indirect evaporating cooler, i.e. its moisture wicking ability, diffusivity and evaporation ability, can greatly affect cooling efficiency and performance. Irregular fibres help to divert moisture and enlarge the wetted area, thus promoting evaporation. A range of fabrics (textiles) weaved from various fibres were experimentally tested and compared to Kraft paper, which has been conventionally used as a wet surface medium in evaporative coolers. It was found that most of the textile fabrics have superior properties in moisture wicking ability, diffusivity and evaporation ability. Compared with Kraft paper, the wicking ability of some fabrics was found to be 171%β182% higher, the diffusion ability 298%β396% higher and evaporation ability 77%β93% higher. A general assessment concerning both the moisture transfer and mechanical properties found that two of the fabrics were most suitable for indirective evaporative cooling applications
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