Urban atmospheric visibility measurement in the different cut-off frequencies

Urban atmospheric visibility is closely associated with our daily life, such as navigation and human health. In the traditional, visibility is measured by professionally trained people. Meters and technologies were proposed to replace the traditional measurement. Digital image processing technology is one of schemes to measuring visibility. Since the good visibility contains more detail data, the high pass filters were used to analyzed and the high frequency information. The cut-off frequency is the key parameter of the performance. In this paper, we use two high pass filters, ideal high-pass filter and homomorphic filter, for visibility monitoring. In the experiments, synthetic and real images are used to show the comparison of the performances between different cut-off frequencies. Keywords—Atmospheric visibility, digital image processing, high-pass filter, cut-off frequency.