Research On Real-time Processing Technology Of Pipeline Magnetic Flux Leakage Inspection Data

Magnetic Flux Leakage(MFL) inspection is the main method of on-line inspecting long distance oil-gas transportation pipeline. Pipeline MFL inspection device is applied to detect defects of pipeline in time in order to prevent pipeline leakage accident. As MFL inspection device works inside the pipeline, therefore it should have a real-time data acquisition and store system. In this paper, an embedded NiosⅡsystem based on FPGA (Field Programmable Gate Array) is developed with SOPC embedded technology, the system is used to realize the real-time acquisition, compression and storage of pipeline MFL inspection data.First, the defects of current MFL inspection system which combines FPGA and processor are analyzed; aiming at the defects, a new system design scheme which applys embedded processor NiosⅡis presentd, and the NiosⅡhardware system based on a single FPGA is designed according to system requirements. Then based on the study of wavelet transform theory and SPIHT compression arithmetic, a pipeline MFL data compression scheme is realized by synthesizing the lifting wavelet transform and SPIHT arithmetic. Finally, uClinux operating system is transplanted to the NiosⅡhardware platform. Based on uClinux, the drive program of acquisition device is developed and the system software implementing data acquisition, compression and storage is designed with multithreads technology.Aiming at each functional module designed in the system, testing methods and corresponding results are presented respectively in the paper. Experiments indicate that each functional module can run stably with good performance, and they can be used in the pipeline MFL inspection device with no problems.The system has some features as follows: Utilizing SOPC technology, device modules can be increased or decreased according to the system requirements at any moment, and hardware & software co-design can be employed freely; In the same time, reliability and operation power of the system are improved greatly via applying FPGA to control data acquisition module; Besides, the utilization of uClinux operating system enhances the acquisition precision of frontal data, simplify the communication between FPGA and peripheral equipment, shortens further system development time and reduced design cost.