CN1930490A - Object detection method and apparatus - Google Patents

Object detection method and apparatus Download PDF

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Publication number
CN1930490A
CN1930490A CNA2004800409709A CN200480040970A CN1930490A CN 1930490 A CN1930490 A CN 1930490A CN A2004800409709 A CNA2004800409709 A CN A2004800409709A CN 200480040970 A CN200480040970 A CN 200480040970A CN 1930490 A CN1930490 A CN 1930490A
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China
Prior art keywords
radiation
target
polarization
amplitude
equipment according
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CNA2004800409709A
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Chinese (zh)
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杰里·豪斯纳
乔纳森·M·威斯特
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MacAleese Companies Inc
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MacAleese Companies Inc
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/88—Radar or analogous systems specially adapted for specific applications
    • G01S13/887—Radar or analogous systems specially adapted for specific applications for detection of concealed objects, e.g. contraband or weapons
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
    • G01S13/04—Systems determining presence of a target
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/024—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00 using polarisation effects
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/41—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00 using analysis of echo signal for target characterisation; Target signature; Target cross-section
    • G01S7/417—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00 using analysis of echo signal for target characterisation; Target signature; Target cross-section involving the use of neural networks

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  • Engineering & Computer Science (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Physics & Mathematics (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • General Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Artificial Intelligence (AREA)
  • Evolutionary Computation (AREA)
  • Radar Systems Or Details Thereof (AREA)
  • Geophysics And Detection Of Objects (AREA)

Abstract

Method and apparatus for detecting objects. In one embodiment, a person entering a secured zone is illuminated with low-power polarized radio waves. Differently polarized waves which are reflected back from the person are collected. Concealed weapons are detected by measuring various parameters of the reflected signals and then calculating various selected differences between them. These differences create patterns when plotted as a function of time. Preferably a trained neural network pattern recognition program is then used to evaluate these patterns and autonomously render a decision on the presence of a weapon.

Description

Object detection method and equipment
The cross reference of related application
The application requires U.S. Provisional Patent Application No.60/525 submission on November 25th, 2003, that be entitled as " object detection method and the equipment (Object Detection Method andApparatus Empolying Polarized Rdiation and Artificial IntelligenceProcessing) that adopt polarized radiation and artificial intelligence process ", 637 rights and interests.The application submitted on January 9th, 2003, the U.S. Patent application No.10/340 that is entitled as " signal Processing of target detection system (SignalProcessing for Object Detection System) ", 016 part continuation application, U.S. Patent application No.10/340,016 is the U.S. Patent No. 6 of on January 29th, 2002 submitting to and authorizing on November 30th, 2004,825,456, the U.S. Patent application No.10/060 that is entitled as " signal Processing of target detection system (Signal Processing for ObjectDetection System) ", 641 part continuation application, U.S. Patent application No.10/060,641 be submitted on May 25th, 1999 and with the U.S. Patent No. 6 of authorizing on January 29th, 2002,342,696, be entitled as the part continuation application of the U.S. Patent No. 09/318,196 of " target detection system (ObjectDetection System) ".The instructions of all described applications all is incorporated herein by reference.
Technical field
The present invention is the method and apparatus of the existence of a kind of remote probe target (including but not limited to the hiding weapon such as rifle or bomb).The present invention further comprises novel signal processing method and the equipment that is used to provide highly reliable target detection.
Background technology
Notice that below discussion relates to many publications and list of references.Provided the discussion of these publications for the more complete background of the principles of science at this, and determined, should not regard the discussion of these publications as and admit that these publications are prior arts for patentability.
On April 20th, 1999, two students in the Columbine middle school in Littleton city, the state of Colorado (Colorado) open fire with the classmate and the teacher of offensive weapon to them.12 teenagers and a teacher are killed, and the dozens injured.In the U.S. of today, the disaster incident of violence of similar Littleton tragic incident takes place often.FBI reports that the criminal of the annual U.S. commits with small arms and surpasses 2.4 hundred ten thousand robbery cases, 5.6 hundred ten thousand attack cases and 165000 rape cases (seeing the American Firearms Industry Journal that is published by National Association of Federally Licensed FirearmsDealers).The data presentation that Center for Disease Control is collected, during 1986 to 1992, the U.S. has write down 247,979 examples " gun death " (by anti-handgun homicide center editor's data).In addition, in the last few years, new threat was developed: the promptly suicide people of dropping a bomb.These are more dangerous and have more destructively that and because their weapon character must detect them a long way off.
Many in the past reducing obtained limited success by the effort of the threat that illegal use caused of small arms.In 20 years, very expensive x ray equipment has been installed all on main airport in the past.These machines generally can detect the metal rifle in the environment of very specialty and sealing.The fixed installation of such equipment requirements occupies very big space, and operating distance is near, and may spend hundreds of thousand and even millions of dollar.
At present on the commercial market available complexity hide the weapon detector do not have a kind of be small-sized, light-duty, portable, be easy to use, at a distance and highly reliable.The exploitation of this equipment will form revolutionary achievement, and will satisfy the long-term needs in enforcement and the security fields.
In following patent and patented claim, described of the present invention: the U.S. Patent No. of submitting to June 5 calendar year 2001, be entitled as " signal Processing of target detection system (Signal Processing forObject Detection System) " 6 than older version, 243,036; That on March 19th, 2002 submitted to, as to be entitled as " hiding weapon detection system (Concealed Weapons DetectionSystem) " U.S. Patent No. 6,359,582; On March 26th, 1998 is with International Patent Application PCT/US97/16944 international publication number WO 98/12573 announcement, that be entitled as " hiding weapon detection system (Concealed WeaponsDetection System) "; And on Dec 14th, 2000 is with the open WO 00/75892 International Patent Application PCT/US00/14509 that announce, that be entitled as " signal Processing of target detection system (Signal Processing for Object Detection System) " in the world.The instructions and the claim of these lists of references are incorporated herein by reference.
Summary of the invention
The present invention a kind ofly determines and the method for the existence of the target of object association that this method may further comprise the steps: come irradiation object with the polarization illumination radiation; Collection is from object first radiation reflection, that have the polarization identical with lighting radiation; Collection is from object second radiation reflection, that have the polarization opposite with lighting radiation; And the multinomial criterion of weighting that adopts first radiation and second radiation, determine the existence of target.The employing step preferably includes, and adopts by chirp Z-transform and handles the multinomial criterion of the weighting that is collected radiation that is transformed into time domain.The employing step preferably includes, and adopts the expansion of one of first radiation and second radiation or both repeatedly amplitudes.Adopt step further preferably to comprise, adopt the multinomial criterion of from comprise following group, selecting: by the chirp Z-transform treatment conversion after time domain, first amplitude of first radiation when zero; By the chirp Z-transform treatment conversion after time domain, second amplitude of second radiation zero time; And first amplitude and second amplitude poor.Adopt step randomly to comprise, adopt between first radiation and second radiation time of arrival difference and/or in time domain or the frequency domain one of first radiation and second radiation or both curve shapes measure, be preferably the ratio of the total area under peak of curve and the curve.
This method preferably is repeated repeatedly, and further comprises the step that the each execution result to this method makes up.This method preferably further comprises the step of coming neural network training with calibration data, and adopts step further to comprise and utilize neural network independently to determine the step that target exists.
Object preferably includes the people, and target optimum selecting ground comprises the hiding weapon of preferably selecting from comprise following group: cutter, small arms, rifle, bomb, explosive release and suicide vest.
The present invention also is a kind of equipment that is used to survey with the target of object association, and this equipment comprises: emitting antenna is used for coming irradiation object with the polarization illumination radiation; First receiving antenna is used to collect from object first radiation reflection, that have the polarization identical with lighting radiation; Second receiving antenna is used to collect from object second radiation reflection, that have the polarization opposite with lighting radiation; And processor, be used to adopt the multinomial criterion of weighting of first radiation and second radiation to determine the existence of target.This processor preferably adopts by the chirp Z-transform processing and is transformed into the multinomial criterion of the weighting that is collected radiation of time domain, and preferably adopts one of first radiation and second radiation or the expansion of both repeatedly amplitudes.This processor preferably also adopts the multinomial criterion of selecting from comprise following group: by the chirp Z-transform treatment conversion after time domain, first amplitude of first radiation zero time; By the chirp Z-transform treatment conversion after time domain, second amplitude of second radiation zero time; And first amplitude and second amplitude poor.
This processor further preferably adopts the time of arrival between first radiation and second radiation poor, preferably adopt one of first radiation and second radiation or both curve shapes in time domain or the frequency domain, and preferably adopt one of first radiation and second radiation or both over time.This processor is preferably to by repeatedly applying lighting radiation and the result that produces makes up to object.Single dual polarization antennas randomly comprises described first receiving antenna and described second receiving antenna.
Object is the people preferably.Target optimum selecting ground is the hiding weapon of preferably selecting from comprise following group: cutter, small arms, rifle, bomb, explosive release and suicide vest.This processor preferably adopts neural network to come the existence of the automatic detection of a target, preferably to each criterion assignment, and determines the existence of target according to the combination of criterion value.
The purpose of this invention is to provide a kind of small-sized, light-duty, remote, portable and available battery-operated detecting devices that is preferably.This makes the preferred embodiment of this equipment can become hand held device, and this hand held device can be used for for example determining whether special entity is equipped with weapon by law enforcement officer and/or military affairs or security personnel.
The invention has the advantages that, the power level of institute of the present invention radiation preferably than normal radar system or current be used on the airport or the x ray of court's porch detection of a target or power level that other imaging system produced much lower.For the present invention, the average power density at object place has the order of magnitude below the Non-ionizing radiation maximum safe limit.
Will be in ensuing detailed description, partly set forth other purpose of the present invention, advantage and new feature and the wider scope of application together with accompanying drawing, and in case examined following instructions, they will partly become apparent for those skilled in the art, perhaps can understand them by practice of the present invention.By means of means of especially in claims, pointing out and combination, can realize and obtain objects and advantages of the present invention.
Description of drawings
The accompanying drawing that is introduced into and constitutes an instructions part shows several embodiments of the present invention, and and instructions one be used from explanation principle of the present invention.Accompanying drawing just is used to illustrate the preferred embodiments of the present invention, and should not be counted as restriction the present invention, wherein:
Fig. 1 a shows simple wave;
Fig. 1 b shows the simple wave of vertical polarization;
Fig. 1 c shows the simple wave of horizontal polarization;
Fig. 2 has provided the block diagram of an embodiment of emission and detection circuit;
Fig. 3 has described to carry at the health diverse location people of rifle;
Fig. 4 a is depicted as, according to dBsm be unit reflected energy to frequency draw, the curve map of pistol radar cross section;
Fig. 4 b is depicted as, according to dBsm be unit reflected energy to frequency draw, the curve map of human body radar cross section;
Fig. 5 and curve map shown in Figure 6 provide the information of the people's volume reflectivity when shining with the radiowave in 2.59 to 3.95GHz and 7.0 to the 10.66GHz frequency bands;
Fig. 7 is that the diagram of the preferred embodiment of the inventive method is represented.Two curve maps on figure the right have shown, can survey the target such as weapon by comparing and have the time domain difference of vibration of the corresponding two groups of waveforms of reflection radiowave of different polarization.In the above with following curve map in, the representative of two waveforms reflects back into the vertical and horizontal polarization radiowave of detector;
Fig. 8 and Fig. 9 are the actual testing apparatus curves of surveying two pairs of time domain waveforms of experimental session generation at pistol.In Fig. 8, someone does not carry rifle; In Fig. 9, same people has carried pistol, and the distance between the maximal value of two curves is much closer;
Figure 10 is the general description to phase place that is used for the complex linear frequency modulation transform that the preferred embodiment of the present invention adopts and amplitude response; And
Figure 11 has described the operating system process flow diagram of the preferred embodiment of the present invention.
The description of preferred implementation
(embodiment)
The present invention includes and be used for the method and apparatus of detection of a target existence a long way off.One embodiment of the present of invention can be used to locate individual entrained hiding gun and/or bomb.The present invention can be used for helping weapon is repelled in any place of safety or " safety area TM" outside, as school, bank, airport, embassy, prison, court, office building, retail shop or dwelling house.Term " safety area TM" be the assignee of present patent application, do the safety area TMThe MacAleese incorporated company of system business, trade mark that is had and service trade (Trade and ServiceMark).
Target optimum selecting ground and object association are for example walked close to the people on doorway, and preferably utilize the low power radio waves of polarization to come the detection of a target.As employed in whole instructions and the claim, term " object " expression includes but not limited to people, knapsack, luggage, sack, shrub etc. to the something of its illumination radiation.As employed in whole instructions and the claim, term " target " indicated object is entrained, wear, hide, or physically be attached to or connect with object or the physical item of opposite and object association, include but not limited to weapon, cutter, gun, rifle, pistol, rifle, bomb, suicide vest, shrapnel, distribution etc.
When radiowave during via air borne, they are to propagate with the traversing similar mode of ripples of crossing ocean surface.The shape description of simple radio signal can be moved up and down or vibrates for repeating, as shown in Figure 1a.This moving up and down of ripple occurs in the three dimensions.Simple wave (W) is propagated.The ripple that is parallel to the propagation plane polarization is called as horizonally-polarized wave.Ripple perpendicular to the propagation plane polarization is called as vertically polarized wave.The height of ripple W or intensity are called as wave amplitude (A).
Fig. 1 b has showed vertically polarized wave, and Fig. 1 c has described horizonally-polarized wave.Vertical polarization and horizontal polarization are considered to the quadrature form of polarization.Can be used for describing other term that concerns between vertically polarized wave and the horizonally-polarized wave is vertical, opposite, cross polarization, or main polarization and complementary polarization.Be mainly used in the document represent that the term of cross polarization is a cross polarization, or abbreviate cross-pol or X-pol as.The thought of polarization is applicable to the transverse electromagnetic wave of form of ownership, no matter they are radiowaves of microwave frequency or such as the light wave of being launched by flashlamp.
The power level of institute of the present invention radiation than normal radar system or current be used on the airport or the power level of the x ray of court's porch detection of a target or the radiation of other imaging system institute much lower.In fact, for the preferred embodiment of the present invention, the average power density at object place has the order of magnitude below the Non-ionizing radiation maximum safe limit.
The present invention preferably is operated in the GHz frequency band.For target detection, the different radio frequency provides different benefit and shortcoming.In the U.S., come the frequency of operation of regulation wireless device by Federal Communications Committee.Each country of the whole world all has similar management organization to distribute use with the managing radio frequency spectrum.Drawn together specifically the quoting of particular frequency range though school bag is described, can utilize multiple electromagnetic radiation to bring advantageously implementation system, and system is not limited by the concrete scope that discloses.
Fig. 2 has provided the non-limitative example of the schematic block diagram of the circuit that is used to implement the preferred embodiment of the present invention.Low power radio transmitter 12 is coupled to modulator 14, wave filter 16 and transmitter output amplifier 18 via first directional coupler 13, and transmitter output amplifier 18 is connected to transmit/receive antenna 80 by transmit/receive switch 20 and preselector 22.Transmit/receive switch 20 is also synchronous by controller 26 and range gating switch 90.The receiving antenna 82 of transmit/receive antenna 80 and detection cross polarization energy is collected the energy that reflects from object.As selection, can randomly use single dual polarization antennas.Polarization selector switch 24 selection levels or vertical polarized antenna or port in the RX path.Transmit/receive antenna 80 preferably not only the signal of emission level polarization, but also receive the level or the co-pol signal of reflection, and receiving antenna 82 preferably receives the vertical or X-pol reflected signal of vertical polarization.Which kind of signal mixing receiver polarization switch 24 is determined at any given time.Pre-filter the 22, the 23rd, bandpass filter is used to prevent: out-of-band-signal enter receiver and may cause pseudo-response or make amplifier saturated, and hinder normal running thus.Pre-filter 22 in the co-pol path undesirable harmonic wave that transmitter is launched of also decaying.
Preferably include begin/stop/controller or the processor 26 of the programming of tilting be used to control transmitter 12 together with local oscillator 30.The output of pulse-pattern generator 28 is connected to modulator 14.The output of local oscillator 30 is via second directional coupler 11 mixer 32 of being fed.The output of transmit/receive switch 20 is also by polarization selector switch 24, wave filter 36 with receive low noise amplifier 34 mixer 32 of being fed.Preferably, the output of the numeral of processor 26 is transmitted to intermediate-frequency gain control amplifier 40, and intermediate-frequency gain control amplifier 40 also receives the main signal input by bandpass filter 41 from mixer 32.Then, the output of amplifier 40 is by range gating switch 90, Hi-pass filter 42, and arrival power divider 44.Range gating controller 21 and range gating switch 90 provide time gated, only make from the signal of the reflecting body (being object or target) at distance equipment desired distance place just processed.The signal that comes from other target that different time arrives is out in the cold.Power divider 44 is divided into two outputs with signal.An output is the amplitude of demodulation in detector 46, produce burst pulse thus, this burst pulse is by wave filter 48, the video amplifier 50, gating sampling and keep stretcher 52, then before being fed to processor 26, be digitized in analog to digital converter 54.Second output of power divider 44 is via power divider 64 phase detectors 65,66 of being fed, and makes the phase shift that can measure return signal with amplitude simultaneously.
Because phase information is very important for carrying out plural frequency domain to time domain conversion, so preferably measure the phase place of reflected signal.Because phase place is a relative term, so, realize phase measurement thus at first by the sampling that transmits with local oscillator signal is mixed the formation reference signal.Obtain the sampling that transmits by directional coupler 13 from transmitter 12, and the sampling that transmits and by the local oscillator signal sampling that directional coupler 11 obtains from local oscillator 30 mixer 9 of being fed together.The filtered device of the output of mixer 98 is carried out bandpass filterings, wave filter 7 amplitude limits that are limited then, with its amplitude stability in coordinating scope.This clipped signal 90 degrees hybrid circuit 72 of being fed, two amplitudes of 90 degrees hybrid circuit 72 outputs equate but have the signal of 90 ° of phase shifts each other.One of output is by first phase detectors 65 of being fed, and another output second phase detectors 66 of being fed.Two phase shift detectors are used for covering clearly 360 degree scopes.The output of phase detectors 65,66 is simulated, and is digitized in analog to digital converter 68 and 70 subsequently.This digitized signal controller 26 of being fed is so that handle subsequently.
Measuring unit " dBsm " is used to quantize radiation reflected, and based on the measuring unit that is called as decibel (being abbreviated as " dB ").Decibel is used for two radiation of comparison or reflective power level.For example, if listen to the antenna tower of wireless someone very close wireless station, then power level will be very high.If the identical antenna tower number of same personal distance is mile far away, then receiving the radio wave intensity will be much smaller owing to distance increases.Decibel can be used for the ratio of this power level is quantified as a number.With just a number is different divided by the vulgar fraction of another number, decibel is the logarithmic form of measuring, and is poor because they are used for more very large quantity, so very useful.Because the power level of radiation can change in big like this scope, so use logarithmically calibrated scale to replace more common linear scale.Being calculated as follows of the difference of two power levels representing with decibel:
dB＝10log(P X/P Y) (1)
P wherein XBe first power level, P YIt is second power level.When utilizing decibel to come two of comparisons to receive radio signals, the power reduction of the signal that receives than distant location is said that becoming is the low a certain decibels of power level of closer position.
" radar cross section " or RCS are the measurements of target sizes.When the generation radiowave made its definite object then, the part of those radiowaves of emission was by target, and another part of those radiowaves is absorbed by object, and the third part of those radiowaves of emission is reflected back to transmitter.The part of reflection wave is big more, and the radar cross section of target is just big more.Therefore, compare with the target with less radar cross section, the target with big radar cross section is easier to survey.The size of the instrumentation radar xsect of target depends primarily on the reflectivity of target and the direction in space of target.For example, suppose radar station on the shore line seeking near deepwater ship.Be parallel to easier being detected of similar ship that the ship of shore line navigation drives away than from land, have the bigger intensity of intensity that reflects than less stern when the radar wave of first ship side portion turns back to radar station from second ship because hit.Therefore, provide second ship of less radar wave effective object to compare, bigger radar cross section is arranged with respect to first gear of radar direction of wave travel " laterally " orientation with stern.
When the present invention is used to survey target resemble the pistol, when determining the pistol direction in the mode that big radar cross section is provided to detector, easier realization detection.For example, and be enclosed within buttocks, make gun barrel directed towards ground and pikestaff point to before or point to after weapon compare, plug is in someone belt buckle back, making the side rifle straight with respect to waist of rifle provides bigger radar cross section.Fig. 3 is that two people's that carry a pistol diagram is represented.On the left side of Fig. 3, shown that someone is placed on waistband front or back to rifle.On the right of Fig. 3, shown that another person is placed on rifle bag, pouch or the holster that is arranged in the side buttocks.Note, similar for the radar cross section of the rifle that makes these two positions, must make this figure with respect to the detector upset or make it towards different directions.
When one (1) square metre is compared, as follows with a decibel measuring unit " dBsm " expression radar cross section:
RCS (is unit with dBsm)=10log (AG)=10logA+10logG (2) wherein A is square metre being the object area of unit, and G is the reflection gain of object.This expression formula hypothesis district is the plane with respect to operation wavelength, and the zone is shone equably by radiowave.If the length of side of square region is " a " rice, then area becomes " a 2" square metre.For being the surface on plane with respect to operation wavelength,
G＝4πa 2/λ 2 (3)
Wherein wavelength X equals 0.3/f rice, and f is to be the frequency of unit with GHz.Thereby
RCS (is unit with dBsm)=10log (4 π a 4f 2/ 0.09) (4)
The indication of this expression formula, if length of side size " a " doubles, then reflection increases 12dBsm, and is perhaps big 16 times with linear power unit representation, xsect.If doubling frequency then reflects the big 6dBsm that becomes, perhaps become 4 times big with linear power unit representation, reflection.Noting, is that the RCS of unit increases 20log (f) with dBsm.In this explanation, ignored complicated edge effect.For example, the dull and stereotyped radar cross section in 6 " * 6 " is-11.3dBsm under the 1GHz.Because coefficient G or gain and f 2Increase pro rata, increase to 8.7dBsm, produced the poor of 20dB so increase to the 10GHz value of making from 1GHz.Yet, it should be noted that typical weapon shape is an on-plane surface with respect to radio wavelength, thereby in fact almost do not have the increase of implementation value.
Data in the table 1 are to utilize the radar cross section of the metal .357 bore pistol of electromagnetic radio waves irradiation in the several frequency bands.Setting up these data comes calibration detectors equipment and reference tolerance is provided.Test configurations is: single port rcs measurement, 16 mean values, time domain gating, and the intermediate frequency that dwindles (IF) bandwidth.
Table 1
Frequency band (MHz) Radar cross section
500-1000 -15dBsm
1000-1750
2650-3000 -10dBsm
2890-3250
9500-10660
Similar, Fig. 4 a provides for radar cross section (RCS) data of crossing over 2650 to 3000MHz frequency range radiation emitted .357 bore pistol.Curve display goes out, for the rifle that is positioned at lateral location the longest dimension of rifle (meaning laterally extend) on the radiowave plane of being launched, in this frequency range RCS from approximately-8dBsm changes in the scope of-11dBsm.Fig. 4 b is illustrated in the RCS that health in the frequency band identical with Fig. 4 a returned or do not have the human body of weapon.Average radar cross section in the frequency band range is-3dBsm, or the average gun of ratio-11dB is returned powerful about 8dB.
Fig. 5 and Fig. 6 provide the measurement to the radio-wave reflection of people in the test cabinet.Fig. 5 has comprised empirical data, and this empirical data indication: when to someone illumination radiation, nearly 63% radio wave energy reflects from human body between 2.59 to 3.95GHz.Fig. 6 demonstrates between 7.0 to 10.66GHz nearly 32% radio wave energy and is reflected.
Generally, the present invention preferably relies on the physical phenomenon of reflection: wherein the incident wave beam of horizontal polarization will be returned by partial reflection and as vertical polarization.The number percent that is converted into the energy of vertical polarization depends on perpendicular to the target shape in the plane of incident direction.If target has the shape of cross section that existing vertical component has horizontal component again,, also will obtain the vertical polarization component even then shine target with horizonally-polarized wave.This vertical polarization component is referred to herein as " cross polarization ", and the horizontal polarization reflection is called as " co-pol ".If with vertical polarization incident wave beam irradiation object and target, then these terms will be opposite.
As mentioned above, the difference average out to of the backscattering between .357 bore pistol and the human body approximately-8dB.At arithmetically, this expression is compared with the situation that does not have rifle, and the combination of rifle and human body will only increase 1.4dB.Suppose that human body difference is the magnitude of 6dB, be not difficult to then be interpreted as what is difficult to detect rifle.Main framing in the human body is vertical, and therefore higher for vertical polarization, the xsect of incident is not surprising.For the most of slide fasteners on the clothes also is this situation.
If use the horizontal polarization of incident, then the health xsect reduces about 6dB, and the cross polarization of vertical polarization now also reduces same amount.Yet it is more constant that the cross polarization of weapon keeps.This meaning, the difference of average 1.4dB can become 7.4dB now, reduces thus by the influence that variation caused between the human body.Thereby, when to as if man-hour, preferably emission level polarization, and reception level and vertical polarization.
Fig. 7 has described the typical operation of the preferred embodiment of the present invention.Utilize and enter protected space or " safety area for the radiowave of horizontal polarization shines in this case TM" the people.The part of these radiowaves is absorbed, and some radiowaves are reflected back to transmitter.Two curves of curve map above transmitter shines the man-hour that does not have rifle, has produced among Fig. 7.These two curve representatives are being used chirp Z-transform (as described below) afterwards, the time domain amplitude (following curve post is designated as " β ") that reflects back into the time domain amplitude (top curve post is designated as " α ") of the horizontal polarization energy of detector and reflect back into the vertical polarization energy of detector.
Following curve map among Fig. 7 has comprised two when detect the time-domain curve that man-hour produced that carries a pistol by detector.As top curve map, the time domain energy level of the horizontal polarization radiowave that this two curves representative reflects from the people (above curve post be designated as " γ "), and the time domain energy level of the vertical polarization radiowave that reflects from the people (below curve post be designated as " δ ").The spacing that is labeled as between the two curve amplitude peaks of " DELTA B " is narrower slightly than the spacing that is labeled as " DELTA A " in the top curve map usually.Generally, when someone has rifle or other any target of the essence of providing reflection existence is arranged, the vertical polarization energy component of returning from target reflection will increase.
Fig. 8 and Fig. 9 are the measurement time domain testing apparatus curves of surveying two pairs of waveforms of experimental session generation at pistol.In Fig. 8, the people does not carry rifle, and the maximal value of two curves 29.6dB of being separated by.Incident polarization is a horizontal polarization, thereby the horizontal polarization that receives is greater than the vertical polarization that receives.In Fig. 9, same people carries a pistol, and the distance between the maximal value of two curves only is 7.9dB now, the existence of indication rifle.
Though test hereto, two highly significants that reduce that receive amplitude difference between the polarization, in other cases amplitude difference reduce may be very little; Thereby can not always rely on this measurement.Therefore, when existence is decision making to weapon, must consider additional parameter or criterion.In addition, in the real world that is not anechoic room, owing to the multipath effect that is caused by ground return and surrounding environment clutter echo, signal will be decayed.As mentioned above, preferably by making the inswept wide frequency ranges of radar that multipath effect is minimized because the cancellation of a frequency can not obtain with another frequency under the different effect of cancellation.Inswept wide frequency ranges provides following attendant advantages: employed frequency spectrum is wide more in the frequency domain, and the time domain time after using proper transformation and the resolution of amplitude are just good more.
Preferred another criterion of using is the relative timing of the peak value of two return signals variations among the present invention.When someone had rifle or bomb, the suitable part that is mainly produced by weapon in the vertical polarization signal was returned with respect to the level that mainly reflects from human body in time and is moved forward.This time shift is another parameter that helps the weapon detection probability.
In addition, when someone weaponize, the shape that two polarizations return is all tended to launch more, and this is because the part of reflection comes from weapon and a part comes from human body.Therefore, the ratio of measuring each peak value that returns and area under curve preferably helps to determine acquisition probability.
At last, when someone weaponize, the absolute amplitude that returns (typically being horizontal polarization) owing to the reflection from weapon makes co-pol tends to bigger, but because the change in size of different people, this itself is not the parameter of heavily weighting.Be far longer than value normally all for adult very if co-pol returns, then this will indicate unusual about special entity alone, might indicate hiding target.When someone carried the bomb that comprises shell fragment, this parameter was very important.
Preferably implement the present invention: the storing value standard set of the signal that the people that this algorithm uses representative never to carry hiding weapon is reflected by solving following algorithm.Preferably utilize many people to measure and these data of editor provide the information of representative among top curve map shown in Figure 7 and Fig. 8.Also used the storing value standard set of representative from the signal of people's reflection of having carried hiding weapon.Equally preferably utilize many people to measure and these data of editor provide the information of representative among following curve map shown in Figure 7 and Fig. 9.In advanced enforcement of the present invention, detector can adapt to its environment by understanding gradually and continuously by there not being carrying arms to enter the reflected signal that many people produced of " safety area TM ".This can include but not limited to neural network by utilizing one of any amount of learning system, realizes.
One of difficult problem of detection rifle scheme of the present invention is the difference of human body.So far all shown data are a use amplitude input all, comes to be transformed into shown time-domain curve from the frequency domain of measuring.Yet as discussed above, this is not enough to provide the reliable indication to the existence of weapon or other target.
The U.S. Patent No. 6 that is entitled as " target detection system (Object Detection System) ", 342,696 disclose new method and the equipment that is used for the detecting hidden weapon, comprise utilizing following time domain approach: the amplitude difference that wherein is used between the co-pol of subject area and cross polarization return determines whether to exist weapon.Preferably utilize following algorithm to improve the sensitivity of target detection: this algorithm adopts can provide the complex linear of amplitude and phase data frequency modulation transform (CZT) by phase information is attached in the conversion.CZT is converted to frequency information temporal information, promptly is transformed into the mathematic(al) representation of time domain from frequency domain a kind of being used for.CZT is the vague generalization of transform, and transform is the discrete form of Laplace conversion.
To the phase place measurement from the polarized wave that may carry people's reflection of hiding weapon is important, because from the polarized wave of hiding the weapon reflection with from the characteristic of the polarized wave of human body reflection a great difference is arranged.Generally, though non-constant from the reflection of hiding weapon, in more limited scope, change.On the contrary, change in time, because human body has the degree of depth and produces reflection in the various degree of depth of human body from the reflection of human body; Therefore reflection is an on-plane surface.The barycenter that returns through conversion is positioned at the following point of body surface.The present invention preferably utilizes this feature in the following manner: use signal processing method to distinguish from the compacter signal of hiding weapon with from the general time/variable in distance signal of human body.The result who uses the on-plane surface data is the minimizing of returning from human body, has improved the ability of system sensitivity and detecting hidden weapon of the present invention.Thereby CZT helps, separating from first signal that radiation produced of target reflection with from the secondary signal that the object radiation reflected such as human body is produced.
The plural number conversion need be known the relative phase shift of each frequency component; Thereby, in order to use CZT, must collection amplitude and phase information during measuring.Therefore, phase detectors are introduced in the instrument; See Fig. 2.Two parts that phase detectors are in fact built-in, each part all is provided the same signal of 90 ° of mutual skews.When the different quadrant repetition values of single part unit, require this quadrature detector can eliminate the polysemy of phase detectors at circle.Because have only a frequency to exist, so preferably measure phase place with respect to launcher signal in preset time.Preferably, the IF signal is carried out the phase measurement of cross polarization return signal.As selection, can the measurement of radio frequency (RF) signal excute phase there be any big difference; Yet it is more difficult and more expensive will obtaining RF measurement accurately.In any method, all utilize phase-shift discriminator to measure return signal with respect to the phase place that transmits.Yet that be concerned about is the coherence who keeps IF.
Preferably, can provide the reference of the accurate IF of return signal, keep this coherence by utilizing additional channel.Preferably, by to emission with local oscillator is all sampled and they are mixed with generation phase detectors reference, realize this point.Because owing to object very has only several nanoseconds near the delay that reception is returned, so noise drops to minimum.Preferably use single phase-detection passage, and it is carried out time-multiplexed, to allow that co-pol and cross polarization passage are separated phase measurement.A kind of method of replacing that generates stable reference is to adopt the stabilized oscillator that is operated in IF, and synchronous the local oscillator and the transmitter oscillator that use the IF reference.
Provided among Figure 10 from the sampling cross polarization amplitude of human body and the vague generalization of phase response and described.Utilize complex linear frequency modulation transform to handle this information.Can the waveform definition among Figure 10 is as follows:
S(f)＝A fil(f)×A (f)e (2πft+δ(f))
Wherein:
A Fil (f)The amplitude response of the bandpass filter the in=frequency domain;
A (f)The amplitude response that cross polarization in the=frequency domain returns;
F=is the frequency of unit with the kilo-mega cycles per second;
T=is the time of unit with the nanosecond;
P (f)The phase response that cross polarization in=δ (f)=frequency domain returns
With the band decomposition of being concerned about is several sections or several case.Case number " N " can be from the 0 any actual value to the number of approach infinity.
Form by the amplitude and the phase place of the reflected signal under each frequency from the data that radar signal is obtained.In order to utilize these values, these values must be converted to the value of representative amplitude to the time.Below make the definition of radar parameter:
The frequency sampling number that N=measures;
Frequency step size between the F_step=sampling; And
F_span=sum frequency scope (N * F_step).
The standard method that frequency signal is converted to time signal is to utilize contrary discrete Fourier transform (DFT) (IDFT).IDFT is transformed to N time-sampling with N frequency sampling.Resulting time-sampling is with the resolution of 1/F_span, and 1/F_step separates equably from the time 0 to the time.
IDFT is defined as follows:
x ( n ) = Σ k = 0 N - 1 X ( k ) e j 2 πnk N
Wherein X (k) is a N frequency sampling (plural number), and x (n) is N time-sampling.
For example, under the situation of N=128 and F_step=7.8125MHz, IDFT provides 128 time-samplings, and each time-sampling was separating for 1 nanosecond in the scope of 0 to 128 nanosecond of time.Yet, because two former thereby prove that this method is not enough.At first, we are not interested in if having time the institute of from 0 to 128 nanosecond, and just interested in from very little (about 10 nanoseconds) timeslice of the reflection of object and target existence.The resolution of the second, 1 nanosecond is too coarse and precise time that can not carry out first-selection of the present invention is measured.
By utilizing chirp Z-transform from the frequency inverted to time, solve this two deficiencies.Chirp Z-transform is according to the operate same with IDFT, but the ability that permission is amplified the district that is concerned about.Forward (time is to frequency) chirp Z-transform is provided by following formula:
X ( k ) = Σ n = 0 N - 1 x ( n ) A - n W nk
Wherein
A = A 0 e j 2 πθ 0
W = W 0 e j 2 πφ 0
And
k＝0，1，...，M-1
A 0Determine the initial radium of chirp Z-transform;
W 0Determine " the spiral coefficient " of chirp Z-transform;
θ 0Determine as a fraction of reference position in whole interval;
φ 0Determine as a fraction of step sizes in whole interval;
N is the number of input (time) value; And
M is the number of output (frequency) value.By using above equation, and being A 0, W 0, θ 0, φ 0, N and M select appropriate value, can select the interval and the resolution of our conversion.For the present invention, preferably with A 0, W 0Be made as 1.
Above equation is with respect to forward (time is to frequency) chirp Z-transform.By getting the complex conjugate of frequency data complex conjugate conversion, calculate contrary chirp Z-transform.For example, for utilizing the time value of N=128 and M=64 calculating from 30 nanoseconds to 40 nanoseconds, we will be provided with:
θ 0=30/128 (zero-time is divided by T.T.); And
φ 0=(10/128)/64 (time range divided by T.T. again divided by output hits).
The data processing of CWD system preferably includes following steps:
1. obtain Frequency and Amplitude and phase value;
2. these values are used the Hamming window;
3. amplitude and phase value are converted to real-valued and empty value;
4. complex values is got conjugation;
5. execution chirp Z-transform;
6. the result is got conjugation;
7. the result is converted to range value from real-valued and empty value.
The more details of chirp Z-transform are provided below with reference to document: " The Chirp-ZTransform Algorithm and Its Applications ", L.Rabiner, et al., MITLincoln Laboratory, Bell System Journal, May-June 1969; " Using theInverse Chirp-Z Transform for Time Domain Analysis of Simulated RadarSignals ", Dean A.Frickey, Idaho National Engineering Laboratory; " Linear Filtering Approach to the Computation of Discrete FourierTransform ", L.Bluestein, GT﹠amp; E, IEEE Transactions on Audio andElectroacoustics, December 1970; And Frederic deCoulon, Signal Theoryand Processing.These lists of references all are introduced into as a reference at this.
Compare with fast fourier transform, the major advantage of chirp Z-transform is, utilizes the resolution of tens of psecs just can obtain point-device time shift data.This provides cross polarization to return the locus of the generation of returning with respect to co-pol with the resolution less than 1 inch.And this provides following information: cross polarization produces in human body, still by the human body front target produced, still on the contrary by body surface produced.Neural network described below is preferably utilized the part of this information as decision process.
For the object that two radars returned and have a different polarization separately, the preferred embodiments of the present invention adopt uses two separately dual-feed antennas of antenna, the one tunnel is used for co-pol and another road is used for cross polarization.First antenna is the emission level polarized wave preferably, and receives identical polarization (co-pol).Second antenna preferably receives only inverted polarized (cross polarization), and does not launch.Normally, this radar uses two receiver channels to keep two received signals separately.As selection, this equipment can carry out multiplexing to signal, and uses microwave switch to come alternately receiver channel to be connected to each antenna, saves the cost of second receiver thus.This saving is very considerable.This method also can be applied to use for every kind of polarization the Antenna Design of independent feed.
Preferably, by the SP2T switch being added on the receiver in the input, realize time-multiplexed, wherein by each input of each antenna feed.Opposite with individual pulse, transmit preferably by the train of impulses that separates such as the cycle of 1 microsecond.To averaging, to negate the strange reading of any unclear chance from returning of each pulse in the set of pulses.Preferably, the set of pulses of 3 to 5 pulses is suitable for this application.
Owing to move the measuring speed of being taken time, can get the reading of a plurality of sequences, as long as in being less than the random time that is preferably 1 millisecond, finish set with respect to human body.This allows with the simplest form design system, because be to carry out co-pol and cross polarization measurement in each frequency, still at first carry out co-pol a frequency range and measures, and carries out cross polarization in the frequency range that replaces then and measures, all with not serious.A kind of method in back allows to use polarization switch to select co-pol to return, and selects cross polarization to return then, and only uses a receiver to measure these two kinds and return.So, can use slow switch with 50 to 100 switching times nanosecond.The repetition frequency that preferably is approximately 10KHz will allow reasonably finish measurement scanning in the time.
Preferably, collected various types of data is used weighting function.Except that being switched to the zero-time cross polarization amplitude after the time domain and being switched to the difference of the zero-time co-pol signal amplitude after the time domain, also have the data of other type that value is also arranged.For example, amplitude that co-pol and cross polarization return and phase value provide certain indication of metal (or other radar reflection material) amount about someone, even bigger the people produced returns smaller returning about big 3dB that the people produced.Yet the people with bomb can produce much bigger the returning of bigger people.In addition,, during approximate 300 milliseconds, preferably get a plurality of frequency ranges for each reading, and calculating mean value preferably.The main body (without any the kind weapon) of safety produces bigger variation (big standard deviation) in 5 values, and the people who has a weapon produces the pattern much tight.Last condition may have 5dB or bigger expansion, and then a condition demonstrates the expansion less than 3dB usually.Therefore, this standard deviation is valuable data.
The present invention preferably gives many such parameters with mark (point), though can use other parameter.First preferred parameter is the amplitude that co-pol returns.This itself is the Discr. of difference, but it is as the reference of other measurement.Have only to exist relatedly with this main body when overall unusual very greatly with indication when its value, just give this parameter mark.For example, if the co-pol amplitude then can be given 3 fens greater than-47dB; If it then can be given 2 fens greater than-50dB; And if it then can be given 1 fen greater than-55dB.The dBm of unit is the power absolute measure with respect to 1 milliwatt.Second preferred parameter is the amplitude that the multiple chiasma polarization returns.For example, if the cross polarization amplitude then can give 2 fens greater than-60dB, and if it greater than-62dB, then can give 1 fen.The 3rd preferred parameter is that last resulting co-pol amplitude and multiple chiasma polarization return the poor of amplitude.For example, if difference then can be given 4 fens less than 5dB; If difference then can be given 2 fens less than 8dB; And if difference then can be given 1 fen less than 10dB.The 4th preferred parameter is the time shift between cross polarization and the co-pol signal.The 5th preferred parameter is the shape of cross polarization waveform; The temporal extension of signal is big more after the conversion, and returning is that the probability of the result of several big reflecting bodys on this main body is just big more.Depend on these parameter values that record with reference to the definite threshold value of experience, preferably give many branches to each parameter.
Then, preferably the score of each preferred parameter is added up, and if summation greater than arbitrarily or statistics go up the upper limit of determining, declare that then someone has weapon or other target; If summation is between the lower limit and the upper limit, then preferably (i.e. test again) warned in report; And if summation preferably declares then that less than lower limit this people is safe.Preferably, two continuous " warning " cause judgement to weapon or target.
Preferably, three times continuous " snapshot " of object carried out accumulative total.Preferably, take snapshot by about 1/4 second increment.Thereby, when someone passes the range gating door, preferably in 3 seconds, finish " snapshot " set, and take " snapshot " set in slightly different position.When weapon may be omitted in certain position, and when being detected in other position, this is more significant.As selection, can randomly require object to rotate a certain angle, for example 120 degree obtain reading in each position simultaneously.Perhaps, multiple devices can be placed on diverse location, and these multiple devices irradiation object simultaneously from different directions preferably.If any one determines to exist weapon in these three snapshots, then preferably declare to exist weapon.Yet, find that if add up to the score of 3 continuous snapshots, the precision of declaring will improve greatly.Randomly can determine declaring of weapon according to following criterion: for three continuous snapshots, each snapshot all has the score of minimum number.
Above process prescription the manual realization of pattern recognition system.As the result of the mankind of subjectivity decision-making, manually specify the mark that is endowed each parameter and they variation with these parameter values.In the process of the method that realizes more accurate definite parameter value (compose and divide) weighting, next step is to use artificial intelligence or mode identification technology, and preferably end user's artificial neural networks is handled.The present invention uses and is called as " pattern-recognition worktable (Pattern Recognition Workbench) " software (PRW), but can use any similar this software.By input data and correct answer, come training program; Then, this program is estimated data, and determines that the optimum weighting of each parameter is so that the precision maximization.Utilize object (for example people's) small sample, data set is can 100% correct.Output is computer code, and this computer code is stored in and will carries out in the computing machine of actual treatment.Then, inner computer is operated in the mode of " not Cha Shou (hands off) ", and the new data of any accumulation is made decisions.When being applied to this, the result is wondrous, and precision of prediction is better than 98% from having improved for about 80% of manual selection weighting for what artificial intelligence was selected weighting.This is because neural network is just learnt when error; For example, when a plurality of people that size and dimension is had nothing in common with each other test and some people when being not suitable for existing pattern, neural network is study just.
Along with progress of research, developed and improved additional criterion.The target of exploitation is that the system of a plurality of by using (for example 3) antenna makes inlet protected.This system allows to check main body from each observation point simultaneously, perhaps checks main body at least in several microseconds.Then, can provide additional parameter, increase the robustness of decision-making from the availability of the data of a plurality of observation point.This can comprise ballot, measures the precision of the little time difference between the reflection to improve with reference to co-pol, as the further indicator of the existence of comparing the vanishing target with large-size with human body.
Figure 11 has provided the process flow diagram of describing preferred embodiment of the present invention operation.
Though in the context of detecting hidden weapon, described the preferred embodiments of the present invention, but the present invention can be used for surveying and/or locating any amount of target, include but not limited to the commodity of unique shape or be attached to cheap label on the commodity, steal system with the reciprocal shop as stock's control.Randomly, can be attached to the present invention in the automatic door control system, for example comprise that automatically-controlled door opens, closes or lock the automatic door control system of equipment.Also can be system as bomb or explosive detection equipment.The detection of other target is to determine which frequency band will produce maximum information to the target of being suspected, accumulates the problem that enough data are come the training of human artificial neural networks then.
Example 1
The detection of a target of test comprises multiple weapon, comprise .22 bore pistol, Glock 9mm semi-automatic handgun, Uzi assault rifle, and the bomb of polyphobia molecule pattern, comprising: comprise nail as the bomb of shell fragment, comprise that the catapult ball is as the bomb of shell fragment and comprise the simulation blasting charge and do not have the bomb of shell fragment.Table 2 shown, about the test sample data of the detection of the multiple weapon that utilizes the irradiation of 9.5 to 10.7GHz frequency bands and horizontal polarization according to the present invention.Only the front is obtained data.Utilize body weight in about 100 pounds to 220 pounds scopes and 12 different people of height in the scope of 5 ' 0 " to 6 ' 2 ", obtain these data.As the table shows, system all is correct for 115 kinds in 116 kinds of security situations, only produces a wrong report thus, and for 283 kinds of weapon situations, has produced 0 wrong report.(NA represents inapplicable)
Table 2
Situation Testing time Correctly Correct percentage Fail to report Wrong report Warning
.22 pistol 60 60 100％ 0 NA 0
Ball 59 59 100％ 0 NA 0
Glock 57 57 100％ 0 NA 0
Nail 62 62 100％ 0 NA 0
Uzi 45 45 100％ 0 NA 0
There is not weapon 116 115 99％ NA 1 0
Though describe the present invention in detail with reference to certain preferred and alternative of the present invention, other embodiment can obtain identical result.The ordinary technical staff in the technical field of the invention will be appreciated that, under the situation of the spirit and scope of claim, can carry out various modifications and raising below not breaking away from.Variation of the present invention and change will be conspicuous for those skilled in the art, and be predetermined to include all this change and equivalents.More than disclosed circuit component intention teach special preferred and alternative to the reader, rather than be used for limiting the scope of boundary of the present invention or claim.Though under the situation of lay special stress on particular hardware configuration or frequency band, described preferred embodiment, can utilize multiple circuit component or frequency range to implement the present invention.Though under the situation of lay special stress on chirp Z-transform, described concrete signal processing method and equipment, also can utilize other multiple mathematical method to implement alternative of the present invention.Above all patents quoted and the whole of publication openly are incorporated herein by reference.

Claims (27)

1. determine and the method for the existence of the target of object association that this method may further comprise the steps for one kind:
Come irradiation object with the polarization illumination radiation;
Collection is from object first radiation reflection, that have the polarization identical with lighting radiation;
Collection is from object second radiation reflection, that have the polarization opposite with lighting radiation; And
Adopt the multinomial criterion of weighting of first radiation and second radiation, determine the existence of target.
2. method according to claim 1 wherein adopts step to comprise, adopts by chirp Z-transform and handles the multinomial criterion of the weighting that is collected radiation that is transformed into time domain.
3. method according to claim 2 wherein adopts step to comprise, adopts the expansion of one of first radiation and second radiation or both repeatedly amplitudes.
4. method according to claim 2 wherein adopts step to comprise, adopts the multinomial criterion select from comprise following group: by chirp Z-transform treatment conversion first radiation, first amplitude when zero after the time domain; By chirp Z-transform treatment conversion second radiation, second amplitude zero time after the time domain; And first amplitude and second amplitude poor.
5. method according to claim 4 wherein adopts step to comprise, adopts the time of arrival between first radiation and second radiation poor.
6. method according to claim 4 wherein adopts step to comprise, one of first radiation and second radiation or both curve shapes are measured in employing time domain or the frequency domain.
7. method according to claim 6 is wherein measured the ratio comprise the total area under peak of curve and the curve.
8. method according to claim 1, wherein this method is repeated repeatedly, and further comprises the step that the each execution result to this method makes up.
9. method according to claim 3, it further comprises the step of coming neural network training with calibration data.
10. method according to claim 9 wherein adopts step further to comprise and utilizes neural network independently to determine the step that target exists.
11. method according to claim 1, wherein object comprises the people.
12. method according to claim 1, wherein target comprises hiding weapon.
13. method according to claim 12, wherein the weapon of Yin Zanging is to select from comprise following group: cutter, small arms, rifle, bomb, explosive release and suicide vest.
14. an equipment that is used to survey with the target of object association, described equipment comprises:
Emitting antenna is used for coming irradiation object with the polarization illumination radiation;
First receiving antenna is used to collect from object first radiation reflection, that have the polarization identical with lighting radiation;
Second receiving antenna is used to collect from object second radiation reflection, that have the polarization opposite with lighting radiation; And
Processor is used to adopt the multinomial criterion of weighting of first radiation and second radiation to determine the existence of target.
15. equipment according to claim 14, wherein said processor adopting are handled the multinomial criterion of the weighting that is collected radiation that is transformed into time domain by chirp Z-transform.
16. equipment according to claim 15, one of described first radiation of wherein said processor adopting and described second radiation or the expansion of both repeatedly amplitudes.
17. the multinomial criterion that equipment according to claim 15, wherein said processor adopting are selected from comprise following group: by chirp Z-transform treatment conversion described first radiation first amplitude zero time after the time domain; By chirp Z-transform treatment conversion described second radiation second amplitude zero time after the time domain; And described first amplitude and described second amplitude is poor.
18. equipment according to claim 17, the time of arrival between described first radiation of wherein said processor adopting and described second radiation is poor.
19. equipment according to claim 17, one of first radiation and described second radiation described in wherein said processor adopting time domain or the frequency domain or both curve shapes.
20. equipment according to claim 17, one of wherein said processor adopting first radiation and second radiation or both are over time.
21. equipment according to claim 14, wherein single dual polarization antennas comprise described first receiving antenna and described second receiving antenna.
22. equipment according to claim 14, wherein said processor is to by repeatedly applying lighting radiation and the result that produces makes up to object.
23. equipment according to claim 14 is wherein to liking the people.
24. equipment according to claim 14, wherein target is the weapon of hiding.
25. equipment according to claim 24, wherein the weapon of Yin Zanging is to select from comprise following group: cutter, small arms, rifle, bomb, explosive release and suicide vest.
26. equipment according to claim 14, wherein said processor adopting neural network is come the existence of the automatic detection of a target.
27. equipment according to claim 26, wherein said processor is to each assignment of described criterion, and determines the existence of target according to the combination of the value of described criterion.
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