Research On Image Defogging Algorithm Based On FPGA

In recent years,with the continuous development of national industry,environmental pollution has become increasingly serious,and haze weather has become a common phenomenon throughout the country.In foggy environment,due to the influence of atmospheric scattering,the visibility is seriously reduced,which leads to the quality of the image taken.and the detailed information in the images cannot be transmitted correctly.In order to remove the influence of haze weather on image information,image de-fogging technology comes into being,which has important application value for image enhancement or restoration.With the progress of technology,only using software to realize image defogging can no longer meet the requirements for image clarity,Using the combination of hardware and software to achieve image defogging is a major choice in the current technological context.In this paper,software and hardware are combined to design image defogging,the FPGA development board used in this paper is Cyclone Ⅳ of Altera Company.The design program uses Verilog language,QuartusⅡ and Model Sim software were used for program setup and simulation verification,and the effectiveness of the method was verified by experiments.Finally,the processed image will be displayed on the display screen in VGA format.Through the combination of FPGA development board and PC software,the image defogging process is realized efficiently.First of all,this paper analyzes the significance and value of the study of image defogging,elaborates on the great contribution made by domestic and foreign image defogging,as well as the methods used in the study process and the solutions to the problems encountered.And the overall frame of the image de-fogging is designed,and the corresponding design is carried out for the power module,storage module,image acquisition and display module.Secondly,the current image de-fogging algorithm is studied.Through analysis and research,the prior algorithm based on dark channel is selected,and the atmospheric scattering model of foggy image is introduced.On the premise of ensuring the effect of image defogging,some of the operations and steps are optimized,which mainly include simplifying the calculation process of transmittance and atmospheric light value in order to make the calculation of transmittance and atmospheric light value more quickly realized on hardware.At the same time,in order to enhance the effect of image defogging,the guided filter is used to refine the transmittance.Finally,this paper realizes the process of image defogging on FPGA.The FPGA model is EP4CE10F17C8 chip,which gives full play to the advantages of fast processing speed and parallel execution of FPGA.The filter operation,dark channel image calculation,atmospheric light value calculation,SDRAM read and write time sequence operation,rough transmittance calculation,refinement transmittance realization and so on are realized.The minimum filtering part of the algorithm and the guided filtering part of the thinning transmittance are analyzed in detail.The final experimental results show that the designed image defogging operation effect meets the expected effect.