The Research And Implementation Of Multi-spectrum Material Analyzer

For police stations(forensic identification and criminal investigation departments)and security agencies in various countries around the world,the common physical evidence extraction process is that criminal investigators first collect physical evidence on the scene of the crime,and then separate and classify the extracted physical evidence,and do a chemical morphing and manual comparison and so on.Finally,extract the physical evidence that meets the conditions.For this method of purely hand-extracted physical evidence,there are major disadvantages such as destruction of vulnerable documents(ancient documents),cumbersome operations(needs very specialized personnel),low efficiency,and large subjective factors.Aiming at the problems of this kind of traditional physical evidence extraction method,this paper is to design a fully automated,highly intelligent,multifunctional multispectral physical evidence analyzer,which can reduce the difficulty of physical evidence extraction,improve work efficiency,and improve the accuracy of physical evidence identification.According to the actual test results,the output monochrome image resolution of the instrument is 1200 DPI,and the monochrome image acquisition takes only 6.3 seconds.Besides,the instrument can realize the identification of fingerprints,counterfeit banknotes or fake passports,and has the function of altering and covering the handwriting,which is very suitable for the field of physical evidence extraction.The paper will analyze the design process of the instrument from the following aspects:(1)By studying the working principle of the CIS sensor deeply,and combined with the relevant technical knowledge in the physical evidence analysis,the design scheme of multispectral physical evidence analyzer was proposed.After a large number of electrical parameters were compared,an optimal hardware platform design scheme was selected.According to the image processing knowledge,a simple,easy to manipulate data processing software was selected.(2)According to the overall design scheme of the system,combined the analog and digital circuit technology knowledge,to complete the circuit design of the hardware system.,including the FPGA main control circuit,the sensor drive circuit,the A/D data summon circuit,and the data storage and transmission circuit,and then had the function introduction and electrical performance parameter analysis for each part.Each module then implemented a software program drive and performed a detailed analysis of the driver's process.(3)By mining the image processing technology and physical evidence analysis technology deeply,the MATLAB software was used to write image feature extraction algorithm and pattern recognition program,of which the feature extraction method was implemented by Gabor filter algorithm,the pattern recognition was done by calculating the small Euclidean distance.(4)Through the measurement of various performance indicators of the instrument,the reliability and stability of the instrument during operation were verified.The actual measurement of each function completed by the instrument proves that the instrument can effectively extract and identify the evidence information.