Research on a fast enhancement method of polarization images in foggy weather based on median filter and polarization modulation
A fast enhancement method of polarization images in foggy weather based on median filter and polarization modulation is proposed to balance between dehazing effect and real-time processing.Firstly,the median filter method is used to estimate atmospheric light.Secondly,the semi-inverse method is applied to get the atmospheric light intensity at infinity,and the restored image is obtained by using scattering model.Finally,the image is adjusted with the degree of linear polarization to promote visual effect.In comparison with other methods,the downsampling method is used in this paper to reduce the image size.Furthermore,the smaller scale of filter window is chosen to decrease the handling time significantly in the premise of maintaining accuracy of atmospheric light estimation.What's more,Polarization modula-tion and histogram equalization methods are utilized to improve the contrast ratio between the target and the background,solving the problem of defogging effect and real-time algorithm better.The experiment shows that the results of this method has a great improvement in three metrics,such as entropy,gradient ratio before and after dehazing,and contrast.For image with a resolution of 1393X 986,the processing time is only 16ms,which fully meets our real-time require-ments.
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