Application Of Digital FIR Filter For The Treatment Of Image Signal In Supervisory Systems

The image signal processing is to process the signals with computers or professional equipments through calculation that are collected, transformed, inferred and evaluated, so as to withdraw information and be easy to apply. Filtering noise in the image signal has been one big hard nut to crack. This paper makes the concrete analysis on the noise signal that exists in the monitoring records in the Northwest Iron Alloy Factory, and designs the new calculating method for the FIR filter based on the characteristics of the interference signal, which can not only speed up the calculation, but also improve the quantity of the image.The interference signal filtering belongs to the filter category. In general, the design of the FIR filter is to find a N rank polynomial to obtain the superior calculating method by the means of the insertion method, the least-square-approaching method or the best-coherence- approaching method. Through analyzing the characteristics of the noise signal in the real monitoring records, the paper puts forward the solution to the problem of the noise signal in the image signal of the real sequence, and deduces a kind of efficient and fast FFT calculating method to improve the simultaneousness of the FIR really sequent method. This calculating method can not only improve the pure image signal effectively, but also double the calculating speed. The calculating method is programmed with the abundant imitation language in VHDL(the applied hardware descriptive language) and the database functions, designed into the simulation with MAX- plusell, edited through the Synopsys FPGA Compiler, downloaded logically and comprehensively to the chip of Flex30K of the Altera Company, and sealed and packed into the finished product integrated circuit. Through the design of the index of the FIR really sequent filter and the field-test, the paper suggests the solution to filtering the noise signal.For resolving the problem of the long delayed time in delivering the image signal and simultaneousness, the paper also puts forward the basic 2 FFTs really sequent butterfly-shaped calculating method. Through the analysis and test, this calculating method is better than the rectangle window functions, Hanming window functions, and Haining window functions. It has better pass belt and the function to reduce the obstacle belt to get the more satisfied calculating result.