Research On Concentration Detection System Of Wastewater Suspended Particles Based On Image Processing

With the development of social economy, the phenomenon of water pollution is becoming more and more serious. How to carry on the water treatment is a problem that brings to high attention of the country. The quality of water is closely related to people’s health, and the sewage concentration of suspended particles is an important indicator of water quality, so accurately detect the sewage concentration of suspended particles is the key to ensure the quality of effluent of sewage treatment and the judgment of sludge discharge time. The traditional concentration of suspended particle in sewage measuring device performs the poor characteristics of real-time and on-line, and the device is soaked and washed by the sewage for a long time, which not only affects the accuracy of the measurement, but also is extremely easy to be damaged.For the lack of the traditional detection device, this topic makes comprehensive comparison of the advantages and disadvantages of photoelectric detection method, ultrasonic detecting method, microwave measurement method and a new detection system of concentration of suspended particle in sewage is proposed based on image processing. The main feature of the system is utilizing the image processing technology and FPGA processor to control the high resolution of waterproof camera to capture the sewage image of sewage treatment process in oxidation ditch based on the different light reflection characteristics of water and suspended particles. Then, the image processing algorithms is used to process the collected sewage image, extracts characteristic values, and calculates the value of concentration of suspended particles in sewage.This topic firstly introduces the key technology of detection system-digital image processing technology, which includes uneven illumination correction, filter and denoising, threshold segmentation and feature extraction of image. Combining with the Matlab tools to make simulation and analysis of collected actual sewage image, then calculates the sewage concentration of suspended particles. Then the whole project design of detection system is introduced including the hardware circuit design and software design, which enables the system to achieve the detection, sending, displaying, voices broadcast of concentration of suspended particles in sewage, and combines with the size of the concentration to control the sludge discharge time. Among it, the hardware circuit design includes minimum FPGA system, image acquisition module, VGA display module, voice broadcast module, Zigbee wireless transmission module, and RS485 communication module block. System software design includes the main program design, uneven illumination correction algorithm design, and adaptive fuzzy threshold algorithm design.The whole article mainly carries on research of the sewage image processing including image preprocessing, image processing and image characteristic value extraction. The key method is the research of threshold segmentation technology in image processing, which accurately calculates the final concentration of suspended particles in sewage and meets the requirements of the subject.