The Application Of Image Method In Smoke Measurement

In recent years,with the rapid development of the national economy and modern industrial technology,the problem of environmental pollution has become increasingly serious and seriously endangered people's health.Meanwhile,it has increasingly attracted attention from all walks of life.Among them,smoke dust particles emitted by the power plants is one of the important causes of environmental pollution.At present,China has already issued emission standards for fixed pollution sources,in order to meet its ultra-low emission standards,it is important to monitor the smoke particle concentration in power plants in real time.At present,most of the smoke particle concentration monitoring products in China are based on the light scattering method and the membrane weighing method,but the light scattering method has poor traceability,and the membrane weighing method is cumbersome and the degree of automation is not high.Based on this,this paper uses the image method to monitor the smoke particle concentration in the flue.Based,the method is a non-contact measurement method.the CCD(Charge Coupled Devices)camera and the illumination source are arranged outside the pipeline,which can not only reflect the distribution of smoke particles in the flue,but also does not change the two-phase flow field,so the measurement accuracy is higher.The smoke particle concentration measurement system designed in this paper mainly includes CCD camera,magnifying lens and illumination laser,which has the advantages of low cost,safety and reliability,and it is conducive to the future industrial promotion.The main work of this paper is as follows:(1)The overall framework of the smoke particle measurement system was designed,and a smoke particle static measurement system with a CCD camera and a laser placed into 90~°was set up in the laboratory.At the same time,the control device for the camera and the laser is designed.The operation of the motor is controlled by a single-chip microcomputer,which can realize the rotation in the horizontal direction and the distance adjustment in the vertical direction with an accuracy of 5?m,so that the captured image is more convenient and intelligent.(2)For the noise of particle images,TV(Total Variation)algorithm is used as a filtering method.The results show that TV denoising can effectively retain the edge information of particles while effectively removing Gaussian white noise and salt and pepper noise.When the image is binarized,an optimized OTSU(Maximum variance between classes)algorithm is used to solve the problems existing in the traditional OTSU algorithm,which Not only narrows the threshold search range,but also takes the intra-class variance of the image into consideration.The algorithm has a better segmentation effect.Well,it can effectively improve the pores of the particle.For the adherent particles,the watershed segmentation method is combined with the morphological reconstruction and distance transformation algorithm.The results show that the algorithm can effectively avoid over-segmentation.(3)The principle of the image method for measuring the concentration of smoke particles was studied in detail,and the static test of the smoke particles was used to demonstrate the feasibility of the image method for measuring the concentration of particles.(4)A smoke particulate matter generating device was set up in the laboratory,which was controlled and operated by the PLC,it can achieve a quantitative ratio of smoke particle concentration in the flue.