基于TMS320C6713的NQR炸药探测系统信号处理
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摘要
近年来,由于国际形势的变化,恐怖活动日渐猖獗,为减少恐怖事件的发生,各国纷纷大力提升安全防范设备的技术水平,安全检查中对炸药的检测尤为重要。核四极矩共振技术由于找到了类似人类指纹特征的炸药本质特性而日益成为安全领域专家关注的焦点。利用常见的炸药中均含有N14的特点,将核四极矩共振技术应用于炸药检测,不仅可以准确地判断炸药的存在,而且可以检测出是何种炸药。但是核四极矩共振信号极其微弱,很容易湮没在噪声和干扰当中,因此,要将核四极矩共振技术应用于实际的炸药检测中,就必须解决核四极矩共振信号的处理问题。
本文在核四极矩共振技术原理的基础上,深入分析了核四极矩共振信号自身的特性,对NQR信号处理方法进行了研究:
1、针对核四极矩共振信号存在严重的振铃拖尾干扰,设计了自适应抵消器,有效抑制了振铃拖尾,提高了NQR信号的信噪比;
2、针对传统的离散傅立叶变换应用于频谱分析,存在截断效应,造成主瓣泄漏和频谱间干扰,降低了信号探测准确性的缺点。本文运用经典功率谱估计对NQR信号进行了处理,有效抑制了泄漏和谱间干扰,提高了探测的准确度;
3,选取高性能的DSP芯片TMS320C6713将核四极矩共振信号处理算法编程实现,并应用于核四极矩共振炸药探测系统样机中,提高了核四极矩共振信号的提取和识别能力。
In recent years, all kinds of terrorisms are gradually prevailing in the world because of the changes of international situation. In order to reduce the occurrence of the terrible events, all countries are promoting their technologies to make sure safety. It is especially important to detect explosives in the field of the security inspection. A new method, Nuclear Quadrupole Resonance (NQR), is able to detect whether there are explosives in a packet, easily and exactly. Many experts in the word are attaching importance to it, and have worked much on it.
All kinds of explosives contain a chemical element, 14N. This characteristic can be used for Nuclear Quadrupole Resonance to detect explosives. This method not only tells the existing of explosives, but also the sort. The Nuclear Quadrupole Resonance signal is rather weak, and it is hard to extract it from background interference and noise, which is limiting the application of the technology. Some difficult problems about the processing of Nuclear Quadrupole Resonance signal must be solved before the technology is applied to detect explosives in practice. Based on the principles of Nuclear Quadrupole Resonance, this article puts forward some useful methods about signal processing according to the characteristic of NQR signal.
There is very serious interference (so-called ringing), an adaptive filter is designed to kill the ringing effectively. The signal-to-noise ratio of NQR signal is remarkably increased.
Leakage of major lobe and interference between consecutive spectrums come into being when a long sequence is cut down in the course of DFT, which reduced the accuracy of signal processing. A method of classic power spectral estimation is applied to eliminate these leakage and interference; as a result, the accuracy of detecting explosives is improved greatly.
A high performance DSP chip TMS320C6713 is used as a platform to accomplish the complicated algorithm of signal processing. It has proven that background noise is effectively cut down, and serious interference is killed. The aim of researching a sample machine of detecting explosives is accomplished, which is a good effort to apply NQR theory to practice.
本文在核四极矩共振技术原理的基础上,深入分析了核四极矩共振信号自身的特性,对NQR信号处理方法进行了研究:
1、针对核四极矩共振信号存在严重的振铃拖尾干扰,设计了自适应抵消器,有效抑制了振铃拖尾,提高了NQR信号的信噪比;
2、针对传统的离散傅立叶变换应用于频谱分析,存在截断效应,造成主瓣泄漏和频谱间干扰,降低了信号探测准确性的缺点。本文运用经典功率谱估计对NQR信号进行了处理,有效抑制了泄漏和谱间干扰,提高了探测的准确度;
3,选取高性能的DSP芯片TMS320C6713将核四极矩共振信号处理算法编程实现,并应用于核四极矩共振炸药探测系统样机中,提高了核四极矩共振信号的提取和识别能力。
In recent years, all kinds of terrorisms are gradually prevailing in the world because of the changes of international situation. In order to reduce the occurrence of the terrible events, all countries are promoting their technologies to make sure safety. It is especially important to detect explosives in the field of the security inspection. A new method, Nuclear Quadrupole Resonance (NQR), is able to detect whether there are explosives in a packet, easily and exactly. Many experts in the word are attaching importance to it, and have worked much on it.
All kinds of explosives contain a chemical element, 14N. This characteristic can be used for Nuclear Quadrupole Resonance to detect explosives. This method not only tells the existing of explosives, but also the sort. The Nuclear Quadrupole Resonance signal is rather weak, and it is hard to extract it from background interference and noise, which is limiting the application of the technology. Some difficult problems about the processing of Nuclear Quadrupole Resonance signal must be solved before the technology is applied to detect explosives in practice. Based on the principles of Nuclear Quadrupole Resonance, this article puts forward some useful methods about signal processing according to the characteristic of NQR signal.
There is very serious interference (so-called ringing), an adaptive filter is designed to kill the ringing effectively. The signal-to-noise ratio of NQR signal is remarkably increased.
Leakage of major lobe and interference between consecutive spectrums come into being when a long sequence is cut down in the course of DFT, which reduced the accuracy of signal processing. A method of classic power spectral estimation is applied to eliminate these leakage and interference; as a result, the accuracy of detecting explosives is improved greatly.
A high performance DSP chip TMS320C6713 is used as a platform to accomplish the complicated algorithm of signal processing. It has proven that background noise is effectively cut down, and serious interference is killed. The aim of researching a sample machine of detecting explosives is accomplished, which is a good effort to apply NQR theory to practice.
引文
[1]石光明,徐更光,王廷增等.核四极矩共振在炸药探测上的应用.火炸药学报,2004,27 (2):70~73
[2]房旭明,徐政,徐玉清等.核四极矩共振炸药探测技术在探雷中的应用.同济大学学报,2003,31(6):729~733
[3]刘兆和,吴腾芳,顾文斌等.核四极矩共振炸药探测原理与实验.解放军理工大学学报(自然科学版),2006,7(1):59~63
[4] M.Ostafin, B. Nogaj. Detection of Plastic Explosives in Luggage with 14N Nuclear Quadrupole Resonance Spectroscopy. Applied Magetic Resonance,2000,571~578
[5] BARRALL G A,DERBY K A,DREW A J. Development of quadrupole resonance confirmation system. Pro SPIE, 2004,5415(2):1256~1267
[6]陈春,张国进,郭华民等.利用核四极矩共振技术探测炸药.波谱学杂志,2005,22(4):367~372
[7]肖立志.核磁共振成像测井与岩石核磁共振及应用.北京:科学出版社,2003
[8]程晓晟,朱佳政.利用核电四极矩共振检测行李包裹中的炸药.物理学报,1998,27(7):423~425
[9] Rebort M.Deas, Ian A.burch and Daniel M.port. The detection of RDX and TNT mine like targets by nuclear quadrupole resonance. Proc. SPIE VOl.4742, p.482-489
[10]何忠伟,房旭明,徐政.核电四极矩共振探测技术研究.核电子学与探测技术,2003,23(6):604~608
[11]丁玉美,阔永红,高新波.数字信号处理.西安:西安电子科学技术大学出版社,2003
[12]曾庆永.微弱信号检测.杭州:浙江大学出版社,1986
[13]原普,毛云志,郭华民.爆炸物检测中微弱NQR信号的处理.电波科学学报,2006,21(2):204~207
[14]胡广书.数字信号处理:理论、算法与实现(第二版).北京:清华大学出版社,2006
[15]吴兆雄,黄振兴,黄顺吉.数字信号处理(下册).北京:国防工业出版社,1985
[16]郝国欣,金燕波,周新建,等. NQR炸药探测系统中减少振铃拖尾影响的几种措施.工兵装备研究,2007
[17]张贤达.现代信号处理.北京:清华大学出版社,1996
[18]田宝凤.基于胎儿心率信号提取的自适应去噪算法的研究:[硕士学位论文].长春:吉林大学电子系,2004
[19]谷源涛.LMS算法收敛性能研究及应用:[博士学位论文].北京:清华大学电子系,2003
[20] J. M. McCool and B. Widrow, Principles and Applications of Adaptive Filters: A TutorialReview.1980 IEEE ISCAS pp.1143-1157
[21]林耀荣.自适应滤波理论及其在回波消除中的应用研究:[博士学位论文].广州:华南理工大学电子与通信工程系,1999
[22]任丽香,马淑芬,李慧芳.TMS320C6000系列DSP的原理与应用.北京:电子工业出版社,2000
[23] TI.TMS320C6000 CPU and Instruction Set Reference Guide. Texas Instruments Incorporated,2000
[24]王深涛.基于TMS320C64X的G.728语音编码器的实现:[硕士学位论文].辽宁:大连理工大学,2005
[25]王潞钢,陈林康,曾岳南,等. DSP C2000程序员高手进阶.北京机械工业出版社,2005
[26]李杰.H.264解码器的DSP移植及优化:[硕士学位论文].华侨大学,2005
[27]黄河.基于TMS320C6201 DSP的信号处理平台设计及实现:[硕士学位论文].西安:电子科技大学,.2003
[28]曾宇.高噪声背景下的信号检测和估计方法研究:[硕士学位论文].杭州:浙江大学,2006
[29]孟庆承,爆炸物及毒品探测技术.核电子学与探测技术,2003,23(4):78~81
[30] M. Ostafin, B. Nogaj. Detection of Plastic Explosives in Luggage with 14N Nuclear Quadrupole Resonance Spectroscopy[J]. Applied Magnetic Resonance, 2000, 19:571～578
[31]李志强,金余恒.基于核电四极矩共振技术的爆炸物检测系统的数据处理及信号识别算法[J].核电子学与探测技术,2006,11(6):586～590
[32] Tantum S, Collins L, Carin L, Gorodnitsky I, Hibbs A, Signal processing for NQR discrimination of buried land mines. Proc SPIE-Int Soc Optical Eng, 3710(1-2):474-482
[33] J. M. McCool and B. Widrow, Principles and Applications of Adaptive Filters: A Tutorial Review.1980 IEEE ISCAS pp.1143-1157
[2]房旭明,徐政,徐玉清等.核四极矩共振炸药探测技术在探雷中的应用.同济大学学报,2003,31(6):729~733
[3]刘兆和,吴腾芳,顾文斌等.核四极矩共振炸药探测原理与实验.解放军理工大学学报(自然科学版),2006,7(1):59~63
[4] M.Ostafin, B. Nogaj. Detection of Plastic Explosives in Luggage with 14N Nuclear Quadrupole Resonance Spectroscopy. Applied Magetic Resonance,2000,571~578
[5] BARRALL G A,DERBY K A,DREW A J. Development of quadrupole resonance confirmation system. Pro SPIE, 2004,5415(2):1256~1267
[6]陈春,张国进,郭华民等.利用核四极矩共振技术探测炸药.波谱学杂志,2005,22(4):367~372
[7]肖立志.核磁共振成像测井与岩石核磁共振及应用.北京:科学出版社,2003
[8]程晓晟,朱佳政.利用核电四极矩共振检测行李包裹中的炸药.物理学报,1998,27(7):423~425
[9] Rebort M.Deas, Ian A.burch and Daniel M.port. The detection of RDX and TNT mine like targets by nuclear quadrupole resonance. Proc. SPIE VOl.4742, p.482-489
[10]何忠伟,房旭明,徐政.核电四极矩共振探测技术研究.核电子学与探测技术,2003,23(6):604~608
[11]丁玉美,阔永红,高新波.数字信号处理.西安:西安电子科学技术大学出版社,2003
[12]曾庆永.微弱信号检测.杭州:浙江大学出版社,1986
[13]原普,毛云志,郭华民.爆炸物检测中微弱NQR信号的处理.电波科学学报,2006,21(2):204~207
[14]胡广书.数字信号处理:理论、算法与实现(第二版).北京:清华大学出版社,2006
[15]吴兆雄,黄振兴,黄顺吉.数字信号处理(下册).北京:国防工业出版社,1985
[16]郝国欣,金燕波,周新建,等. NQR炸药探测系统中减少振铃拖尾影响的几种措施.工兵装备研究,2007
[17]张贤达.现代信号处理.北京:清华大学出版社,1996
[18]田宝凤.基于胎儿心率信号提取的自适应去噪算法的研究:[硕士学位论文].长春:吉林大学电子系,2004
[19]谷源涛.LMS算法收敛性能研究及应用:[博士学位论文].北京:清华大学电子系,2003
[20] J. M. McCool and B. Widrow, Principles and Applications of Adaptive Filters: A TutorialReview.1980 IEEE ISCAS pp.1143-1157
[21]林耀荣.自适应滤波理论及其在回波消除中的应用研究:[博士学位论文].广州:华南理工大学电子与通信工程系,1999
[22]任丽香,马淑芬,李慧芳.TMS320C6000系列DSP的原理与应用.北京:电子工业出版社,2000
[23] TI.TMS320C6000 CPU and Instruction Set Reference Guide. Texas Instruments Incorporated,2000
[24]王深涛.基于TMS320C64X的G.728语音编码器的实现:[硕士学位论文].辽宁:大连理工大学,2005
[25]王潞钢,陈林康,曾岳南,等. DSP C2000程序员高手进阶.北京机械工业出版社,2005
[26]李杰.H.264解码器的DSP移植及优化:[硕士学位论文].华侨大学,2005
[27]黄河.基于TMS320C6201 DSP的信号处理平台设计及实现:[硕士学位论文].西安:电子科技大学,.2003
[28]曾宇.高噪声背景下的信号检测和估计方法研究:[硕士学位论文].杭州:浙江大学,2006
[29]孟庆承,爆炸物及毒品探测技术.核电子学与探测技术,2003,23(4):78~81
[30] M. Ostafin, B. Nogaj. Detection of Plastic Explosives in Luggage with 14N Nuclear Quadrupole Resonance Spectroscopy[J]. Applied Magnetic Resonance, 2000, 19:571～578
[31]李志强,金余恒.基于核电四极矩共振技术的爆炸物检测系统的数据处理及信号识别算法[J].核电子学与探测技术,2006,11(6):586～590
[32] Tantum S, Collins L, Carin L, Gorodnitsky I, Hibbs A, Signal processing for NQR discrimination of buried land mines. Proc SPIE-Int Soc Optical Eng, 3710(1-2):474-482
[33] J. M. McCool and B. Widrow, Principles and Applications of Adaptive Filters: A Tutorial Review.1980 IEEE ISCAS pp.1143-1157