Research On Foggy Image Sharpening Method Based On Dark Channel

In hazy weather,the image acquired by people is often affected by some particles in the atmosphere,resulting in a large scattering change between the light and the original propagation direction,and the energy of the light will also attenuate in the propagation process.When the scene reaches the human eye or camera equipment,the image quality will be greatly attenuated.The overall contrast of the acquired images is reduced,the details are lost,and the image quality is too low,which will have a great negative impact on residents’ lives and industrial production.Therefore,it is of great theoretical significance and practical value to study more reasonable ways of de-fogging and make the image clearer after de-fogging.Dark channel prior algorithm can achieve a good de-fogging of the image,and the processed image is clear and natural.However,for some outdoor images containing sky area,the sky area is prone to color distortion and discoloration and noise and other problems after processing.To solve this problem,the paper proposes an improved algorithm based on the combination of light and dark channels and fog map mean.First of all,for the problem that the value of atmospheric light in the dark channel is more accurate,the atmospheric light value is calculated by combining light and dark channels,which makes the atmospheric light value obtained more robust.Secondly,for the problem that the weight value of the haze retention parameter is relatively simple,the value of dividing the mean value of the fog map by the mean value of the bright channel is used to solve the problem that the weight value is simple,so that the fog is clear and natural after defogging.Finally,for the problem that the value of transmittance is more adaptive,the normalized mean value of fog map dark channel pixels is used to constrain the transmittance threshold to complete fog image clarity processing.Through experiments,the defogging results of the improved algorithm in this paper,the defogging results of the dark channel algorithm and other algorithms are compared and analyzed from two aspects of subjective evaluation and objective data analysis.The comparison results confirm that the improved algorithm in this paper has improved the subjective visual effect and better data index,which fully indicates that the improved method proposed in this paper solves the defogging failure problem of dark channel for some outdoor images containing sky areas,and obtains natural clear images.