Suburban atmospheric visibility sensing by an image degradation processor: model development and field test

Abstract

This study describes some preliminary results of a new approach which seeks to develop a method by which uneven decay of atmosphere can be described by the fluctuation of a degradation parameter, k, extracted from online recorded images. The proposed processor is a combination of the empirical model for atmospheric non-homogeneity and an image degradation method. Estimation of the other parameter, C _ave, derived from k values was an attempt to quantify the blurred level of atmospheric visibility according to the full-scale image computation. The C _ave of code A–E images ranged from 0.437 to 0.831, and the related visual range observed by investigators was from 14.1 to 3.0 km, respectively. The standard deviation of C _ave reveals that non-homogeneous degradation of blurring atmosphere happens. Low visibility related with a small visual range and a degraded image is companied by a large C _ave and inherits high variation from heaving k values. Because of fluctuation and full-scale image representation, C _ave is more meaningful and sensitive for atmospheric decay measurement than the prevailing visibility equal to the distance at which the farthest target can be recognized. Finally, a field test was applied to confirm a good correlation between observed visual range and two parameters (k and C _ave).

Acknowledgement

The authors thank the National Science Council of Taiwan for financially supporting this research under contract no. NSC 93-2211-E-241-002.