Research On Image Enhancement Technology Of Transmission Line Visualization Device Under Fog And Haze Weather

With the rapid development of "smart grid",the transmission line inspection method of the power grid company has been changed from the traditional manual inspection to automatic monitoring of the line visualization system.The line visualization system mainly consists of front-end image video device and terminal server.Under haze conditions,the front-end image video device cannot capture the environmental conditions around the line and result in transmission lines not being able to give timely alerts when they encounter external damage.Therefore,it is important to study high quality,fast,stable and pervasive dehazing algorithms for the proper operation of line visualization systems in power grid companies.In this paper,we adopt a dehazing method based on the physical model of atmospheric scattering,and improve the algorithm for the two important parameters of the model,such as atmospheric light and transmission.The main work of this paper is as follows:(1)Aiming at the main problems of the current dehazing methods based on the atmospheric scattering physical model,such as the single method of obtaining atmospheric light,the high value of atmospheric light and the dark color of dehazing image,a method of obtaining atmospheric light based on the expression of gray and dark transmission is proposed in this paper.To solve the problem of poor robustness of a single window in the conventional dark channel of the original haze image,an adaptive filtering window is proposed to refine the transmission in the process of obtaining the expression of the gray and dark transmission.To reduce the influence of white objects in the near-field part of the image on transmission when using the color attenuation prior to obtain the transmission,this paper uses morphological erosion operation to eliminate this influence.(2)Aiming at the problem that the brightness of atmospheric light dehazing algorithm based on gray and dark transmission is excessively enhanced in the sky region of the image,a prior dehazing algorithm of dark and bright channels based on sky region segmentation is proposed in this paper.The original haze image is divided into sky region and non-sky region by binary segmentation,then using the bright channel prior to obtain the transmission in the sky region and using the dark channel prior to obtain the transmission in the non-sky region.To ensure the result of image segmentation is accurate,this paper proposes to use the luminance plurality based on HSI color space as the segmentation parameter and multiply it by a factor less than 1 as the final segmentation threshold.By comparing with the traditional two-dimensional Otsu algorithm,it is found that our segmentation algorithm works better.(3)In this paper,we evaluate the dehazing images by subjective evaluation and objective parameter evaluation.This paper designs comparison experiments to compare the atmospheric light dehazing algorithm based on gray and dark transmission and the dark-bright channel prior dehazing algorithm based on the segmentation of sky region with other algorithms.Experimental results show that the proposed algorithm is superior to other comparison algorithms in controlling image color distortion,improving image contrast and restoring image details.