The Research On Defogging Method Of Visible-light Image In Complex Weather Environment

When an industrial camera captures a target in a complex weather environment,due to the influence of suspended particles in the air,the quality of the captured image will inevitably be affected,leading to problems such as unclear image,hidden target information,and less useful information in the acquired visible image.Therefore,there is an urgent need to clarify the captured visible-light image,repair the impact of complex weather environment on the captured image quality,and improve the practicability and application value of the image.Based on this,this article focuses on the clear processing of visible-light images under complex weather conditions,and builds an RGB-HSI(The conversion between the RGB color space and the HSI color space,RGB-HSI)color space conversion algorithm that is easy to be implemented on FPGA(Field Programmable Gate Array,FPGA)hardware.Subsequently,this paper proposes an improved dark channel defogging algorithm based on the HSI color space(Hue-Saturation-Intensity color space,HSI color space),and validates its effectiveness on the FPGA hardware platform.The innovations of this paper are as follows.Firstly,in view of the high computational complexity of the traditional RGB-HSI conversion algorithm,which is not conducive to FPGA hardware implementation,an RGBHSI color space conversion algorithm,named S-SC algorithm,is proposed.The experiment results show that the S-SC algorithm can reduce the computational complexity of the space conversion between the RGB color space(Red-Green-Blue color space,RGB color space)and the HSI color space.Besides,the S-SC algorithm has almost the same accuracy compared to the geometric derivation algorithm.In other words,the S-SC algorithm can reduce the complexity while ensuring the conversion accuracy,and has the advantages of high restoration degree and low calculation time.Secondly,aiming at the defogging processing of captured degraded visible light images,this paper proposes an improved dark channel defogging algorithm(IDCP)based on HSI space.The experimental results prove that the proposed asymmetric mean filter can effectively improve the gray value mutation phenomenon which can hardly be removed in the traditional dark channel images.Subsequently,a global atmospheric transmittance calculation method is proposed to effectively solve the unadapted issue that the traditional DCP(Dark Channel Prior,DCP)algorithm exists while processing the images contain the large-scale and high-brightness sky region.The proposed global atmospheric transmittance calculation method can effectively avoid the distortion phenomenon while processing the large-scale and high-brightness sky region.Besides,compared with the RGB color space,defogging in the HSI color space can effectively avoid the mutual influence of color components while processing the image data and improve the effect of defogging.Finally,in order to verify the performance of the proposed S-SC algorithm and the proposed IDCP algorithm,this paper uses FPGA hardware as the verification platform to analyze the performance of the algorithm.The experimental results prove that the S-SC algorithm can greatly reduce the consumption of LUTs(Lookup Tables,LUTs)resources at the cost of lower Register resources and Flip Flop resources,which resulting in high conversion accuracy and good output timing performance.In addition,after the IDCP algorithm is implemented on the FPGA hardware platform,there is only a 5 lines delay of image data between the input and the output.It can prove that the FPGA-based IDCP algorithm has the characteristics of low logic resource consumption and low time delay,ensuring that the proposed IDCP algorithm has good defogging performance while meeting real-time processing requirements.