Abstract:
Apparatus and methods for detecting concealed personal security threats may comprise conventional mirrors and less conventional arrays of Hall-effect sensors and/or magnetometers, preferably at least two axis or three axis sensors or sensors mounted back-to-back. The concealed personal security threats may comprise, for example, sticky devices consisting of geographic position sensors for covertly broadcasting motor vehicle location data, of so-called Improvised Explosive Devices (IED&#39;s) which may be covertly or openly affixed to, for example, the undercarriages of motor vehicles using strong magnets and later exploded, the former giving away private location information, the latter causing damage to the motor vehicles to which they are affixed and sticky containers for hiding contraband among other “sticky devices.” Magnetic fields detected by, for example, arrays of Hall-effect sensors and the like may be quantified and stored in processor memory as a vehicle magnetic field signature. A processor receiving magnetic field data collected by the arrays may retrieve and subtract known signatures from acquired magnetic field data for a given vehicle to obtain location for a magnetic field on the vehicle that may be of potential interest as a risk.

Description:
This application is a continuation-in-part of U.S. patent application Ser. No. 13/006,023 filed Jan. 13, 2012, no allowed, entitled “Handheld and Imbedded Devices to Detect Sticky Devices Using Magnets” of David J. Icove and Carl T. Lyster incorporated herein by reference as to its entire contents. 
    
    
     TECHNICAL FIELD 
     Embodiments relate to the technical field of apparatus and methods for detecting concealed personal security threats, for example, sticky devices consisting, for example, of geographic position sensors for covertly broadcasting motor vehicle location data and of so-called Improvised Explosive Devices (IED&#39;s) which may be covertly or openly affixed to, for example, the undercarriages of motor vehicles using strong magnets and later exploded, the former giving away private location information without the knowledge of a driver or passengers and the latter causing damage to the motor vehicles to which they are affixed and potentially harming a driver, passengers and nearby persons, and, in particular, for detecting a magnetic field surrounding the sticky devices. 
     BACKGROUND 
     The situation of living and operating in a free nation in which covert activities ma invade upon personal privacy and, at the same time, a hostile national environment during high terror risk or wartime conditions creates an environment where, for example, vehicles become an available target for espionage and surveillance activists, for terrorists and for insurgents to typically place magnetically affixed location finders and even bombs to motor vehicle, for example, to undercarriages, bumpers, wheel wells, roofs, engine compartments and quarter panels. Due to their affinity to strong magnetic adherence to these metal parts, the bomb devices are called “sticky IEDs.” The location trackers with associated Global Positioning System radio frequency broadcast are called “sticky location finders.” Also, containers are often used with magnets to permit the containers to be concealed under the vehicle body or in wheel wells. For example, small containers with affixed permanent magnets are used to contain a vehicle ignition/lock key so that a driver, not having the key and the vehicle being locked, may, knowing the location of the container, obtain the key and drive the vehicle. Other containers using magnets may be used to contain illegal drugs, contraband, valuable documents, money and the like. Such a device may be referred to herein as a “sticky container.” A “sticky device” is used herein to refer to any of the above. Other “sticky” devices may come to mind to one of ordinary skill in the art. 
     Sticky IED devices have been known to exist since at least the year 2000 and their use has been increasing. Rigged with magnets so that they will adhere to the undersides of automobiles and armored vehicles, sticky IED&#39;s are often detonated by remote control or with timers. Consequently, sticky IED&#39;s (and also sticky location finders) may be covertly placed at one point in time. Sticky IED devices may be activated once the car is moved. The sticky IED&#39;s then may be guaranteed to have at least one victim operating the vehicle. According to sources quoted on Dec. 3, 2010 via National Public Radio, currently 100 IED&#39;s are detonated each month in Iraq. The number previously was at 50 per month. In the month of November, 2010, the number of sticky IED&#39;s was 45. According to Ahmed Mawla, an explosives disposal instructor in Iraq, during the most painful times in Iraq, the number of IED&#39;s detonated reached fifty per day. Also, as of December, 2010, National Public Radio alleges that as many as 2196 deaths of US service members are attributable to IED&#39;s. 
     The sticky location finder is activated and can continuously monitor and broadcast vehicle location data as the vehicle moves in real time via radio frequency channels. Other initiation devices consist of movement detection mechanisms that activate the GPS unit (to save battery) or to destroy the targeted vehicle when it is started and then moved. Magnetic components of sticky IED&#39;s, sticky location finders and sticky containers may consist of imported components including, more importantly variable magnetic field characteristics and alloy compositions, for example, ceramic magnets versus AINiCo (aluminum, nickel, cobalt) versus SmCo (samarium-cobalt) versus NdFeb (neodymium) or other permanent magnets of different alloy compositions and percentage weights. 
     Sticky containers may be used by rental car companies to hide keys to vehicles left on city streets for use by drivers needing vehicles that are available for rent by the hour or day. A car owner may use a sticky container to hide a key so that a co-owner, knowing the location may find the key and use it. At times, such intended placement of a magnetic container at a particular location may become unknown just as it may be the intention to use a sticky container to intentionally hide, for example, illegal drugs. Consequently, there may be a need for a magnetic field sensor for detecting such sticky containers. 
     The responsibility for detecting/knowing a location of these sticky devices typically rests, first, with the vehicle driver or owner. When vehicles enter compounds, security personnel, typically use mirrors to examine undercarriages and other metal portions of motor vehicles. Referring to  FIG. 1A , there is shown a drawing of a known mirror detector  100  held by a user  160 . The detector may comprise in combination a flashlight  115  for shining on a mirror  110  in order to illuminate an undercarriage of a vehicle  150 . Detector  100  typically is formed as a pole mirror mount and handle  120  on wheels  140  so that user  160  may twist and maneuver the mirror to visually identify any unusual devices that may be affixed to the undercarriage. 
     In order to view above a vehicle and with reference to  FIG. 1B , a detector  110  may be light-weight and have a mirror  110  mounted on an extendible pole  118  and carried and passed across a top of a vehicle when the vehicle arrives at a security check point using the extendible pole mount and handle  120  (handle not shown but see  FIG. 1A ). A teo-handed grip may be useful for lifting a mirror. These methods of vehicle examination are not infallible since they rely on human discretion to look for, identify, and remove these devices. Most of these sticky devices are camouflaged so as to not be easily seen, for example, by using black surface paint, tar, undercoating and other materials so as to blend in with the car surface. Consequently, mirrors  110  are not perfectly effective. 
     Carl V. Nelson et al. for Johns Hopkins University has performed research in the field of detecting and identifying metal targets. U.S. Pat. No. 6,853,194 describes an electromagnetic target discriminator sensor system and method for detecting and identifying metal targets. A prior art system describe by  FIG. 1  suggests a pulse transmitter and receiver coil for determining the existence of a metal target by inducing an eddy current in the target. Such a system has an obvious disadvantage in that, by inducing a current (or voltage), a user of the depicted detector may trigger a target device to actuate and have disastrous consequences for the user of the equipment. Nevertheless, Nelson persists in utilizing a wireloop transmitter and a wireloop receiver for, for example, detecting a buried, metal target bomb in his &#39;194 patent disclosure and drawings. U.S. Pat. No. 7,227,466 describes the use of an expendable metal detector that may be in the form of a hand-thrown or guided missile that may be launched toward an improvised explosive device (IED). Once the device lands, the tip may be buried next to the IED and magnetometers actuated. The missile tip may contain an impact switch for activating first and second magnetometers spaced from one another in the missile. In this manner, the magnetic fields detected by the magnetometers may be differentiated at a difference amplifier and the result transmitted by telemetry to a decision station. Clearly, the use of a missile with differential analysis may help to locate the sticky device while preserving the safety of deploying personnel. 
     UK published patent application GB 2 248 692 published Apr. 14, 1992 to John Bagshaw discloses a magnetic anomaly detector having a plurality of magnetic flux sensors distributed over an area and a means for calculating magnetic field intensity within the sensor area and so determine a location of the anomaly. US published patent application US 2010/0102809 published Apr. 29, 2010 to Wayne May is similar in providing a plurality of sensing arrays  100  and a real time display  109  for displaying, for example, a located improvised explosive device. These devices suffer from a problem of more simply corresponding the arrays to their respective displays. For example, May suggests calculating outputs, ground state registration, normalizing the output and so on. Moreover, the array may comprise 12 sensors per  FIG. 2  to cover 600 cm or 6 meters—a very long array approximating more than 18 feet. 
     In the field of automobile detection and identification, it is known to obtain and compare an induction signature of a motor vehicle with a stored induction signature and so identify the motor vehicle from U.S. Pat. No. 6,342,845 of Hilliard et al. and U.S. Pat. No. 7,771,064 of Leibowitz et al. A plurality of successive induction measurements or an induction signature for a given vehicle passively captured as the vehicle passes over a blade sensor in a lane of a road may classify the vehicle (for example, as a truck or car) and even identify the vehicle. Typically, the entire vehicle passes over the blade sensor which may be buried in a road surface. As the vehicle passes over the blade sensor, the signature is captured over the time it takes for the vehicle to pass over the blade sensor. 
     In the field of automotive vehicle maintenance (including flying vehicles such as helicopters), it is known from U.S. Pat. No. 4,100,491 to provide a soft iron core pole piece which may be magnetized by a magnetic field. The magnetized soft iron core causes engine oil particles of the engine to adhere to the polarized magnet. As engine particles accumulate on a probe portion for mounting in an engine oil flow line, an electronic control circuit identities the accumulation of engine particles in oil (dirty oil) and provides a green (clean oil), yellow (oil caution) and red (dirty oil) indication to a driver or one responsible for engine maintenance. A feature of the circuit is the application of a brief alternating current to the soft iron core to remove residual magnetism (degauss to make the indicator green again), for example, after the engine oil is changed. 
     Furthermore, besides magnetometers and soft iron core detection circuits. Hall-effect sensors are known for use, for example, in determining the angular velocity of engines by detecting a magnetic field with each turn of an engine shaft. Edward Ramson, in his book,  Hall - Effect Sensors , Elsevier, 2006, provides a thorough explanation of the use of Hall-effect sensors. Ransom includes chapters providing exemplary linear Hall-effect sensor circuits for, for example, head-on sensing of magnets. However, Ramson explains that Hall-effect sensors are notoriously variable in terms of their magnetic field detection characteristics. A typical remnant induction or flux density B present in a closed ring in a saturated state for a typical ceramic magi may be 3850 Gauss. For an AlNiCo magnet, a range in B may be from 8200 to 12,800 Gauss and for NdFeB up to 13,500 Gauss. Hall-effect sensors are north and south pole magnetic field sensitive on/off binary devices operative at a relatively high sensor level point and turn off at a relatively low level of gauss and different polarity. Magnetic field strength diminishes with the square of the distance. So the closer any magnetic field detector is to a magnet of a given polarity, the more likely the detector will turn on. Temperature also impacts both the residual level of gauss in a permanent magnet and also impacts the characteristics of the field detector. 
     Other devices are known such as chromatic cameras for detecting small differences in color variation. Image segmentation analysis is known for comparing an image with a known image and detecting an anomaly. Moreover, radio frequency transmission detectors (typically involving wide band antennae covering a large range of frequencies) may be utilized to detect radio frequency transmission to/from either a location finder device or emanating from a poorly shielded radio frequency transceiver used to detonate a sticky IED. 
     In view of the above, there is clearly a need in the art for improved systems and methods for detecting the presence of sticky devices, for example, of the GPS, IED or container type so that they may be safely deactivated and removed from the vehicles on which they are found. 
     SUMMARY 
     Specific example embodiments of apparatus and methods disclosed provide for an instrument to assist in the inspection of concealed security threats consisting of magnetized improvised explosive devices, known as sticky IEDs, which cling to the undersides of motor vehicles, sticky UPS devices used for surveillance purposes and sticky containers. IED devices are typically placed by insurgents and terrorists whose mission is to kill, maim, or terrorize the passengers and nearby individuals. The same or variations on specific example embodiments, according to the present disclosure, may also be used to detect other types of magnetically affixed devices, including global positioning systems used to surreptitiously track the vehicle, illegal substances, embargoed materials, hazardous chemicals and materials, and hazardous chemical vapors or materials. In addition, this instrument can also be used to search within any contained space, such as railroad boxcars, aircraft passenger, cargo, and luggage compartments, liquid cargo containers such as tank cars, tractor trailers, ships, and storage tanks. Embodiments may preferably involve the use of passive reception of electro-magnetic energy of any kind to avoid inadvertent actuation or detonation. Active transmission of energy is preferably avoided, even light energy. Nevertheless, one embodiment may involve a known mirror system per  FIG. 1  modified to further include magnetic field sensors, optical chromatic scanning and camera image capture and passive radio frequency reception in combinations selected for the application. 
     A method for inspecting these vehicles may consist of an embodiment consisting of various arrangements of Hall-effect sensor devices having one or more axes as explained further below. A known source of inexpensive Hall-effect sensors is Allegro Microsystems LLC with headquarters in Worcester, Mass. Hall-effect sensors are transducers that will vary its output voltage in response to changes in magnetic field. Hall sensors are used for proximity switching, positioning, speed detection, and current sensing applications. A preferable Hall-effect sensor is one of the linear output type where the output varies linearly with the input. The Hall-effect sensor may operate as an analogue transducer, directly returning a voltage. Digital binary to analog converters are used with, for example, a plurality of Hall-effect sensors operative at selectably different sensed values of magnetic field in gauss to provide the analog output. With a known magnetic field, its distance from the singular Hall sensor plate can be determined by the square of the distance equation in combination with distance calculations, for example, made from automatic camera focusing optical systems. When using groups of sensors operating at different gaussian ranges and environmental temperatures, the relative position of the magnet can also be deduced. 
     A disadvantage of a Hall-effect transducer is that, in its simplest form, it is sensitive to a magnetic field in only one axis and field polarity. On the other hand, Hall-effect transducers may be fabricated to be sensitive as a two-axis or three-axis sensor. In one embodiment, two Hall-effect sensors are used back-to-back to improve range and overcome the problem of not being able to detect fields of either North or South polarity. For example, one may place a pair of devices on a single silicon die by aligning their structures at 90° to one another for a two-axis sensor and/or 180° back to back. In a similar manner, three transducers on a single die may form a three-axis sensor. Through experimentation with known Hall-effect sensors, Hall-effect sensors may be arranged back-to-back to increase range. When connected to an operational amplifier and LED&#39;s, the Hall-effect back-to-back sensors may be used to distinguish a magnet field regardless of the field&#39;s polarity. A typical range for magnetic field sensing less background noise, by a single Hall-effect sensor used with an operational amplifier and a single LED display per sensor is approximately less than six inches to detect a magnetic field of approximately 3000 Gauss. With back-to-back Hall-effect sensing the range is increased to between six and seven inches and with the advantage of detecting either N or S polarity. A prototype of three Hall-effect circuits spaced on a mirror (center and periphery) has been constructed and shown to exhibit a 10 cm range per single Hall-effect sensor and ample coverage is achieved with a 12 to 18 inch diameter mirror. Consequently, in embodiments, a Hall-effect sensor as further described herein may be separated from another similar sensor by less than about nine inches. With back-to-back and/or multiple axis Hall-effect sensing or hybrid magnetometer sensing, the range may be increased. 
     On the other hand, Hall-effect circuits have advantages over either a magnetometer or an iron core magnetic field sensor. For one, a Hall-effect sensor need not be de-gaussed before it is re-used. A magnetometer cannot distinguish between a magnet and other metallic objects that may be attached to an undercarriage. A magnetometer wand does not exhibit a metallic profile. A magnetometer may introduce its own magnetic field and may be therefore unsafe in the presence of an IED with its own sensors for detecting a magnetic field and detonating. A Hall-effect sensor does not emanate a magnetic field and therefore is intrinsically safer. 
     Extremely strong magnets are needed to conform with the sticky IED, container or location finder devices and quickly and semi-permanently cause it to adhere to a surface on the vehicle. A common form of magnet used to affix sticky IEDs is known as an Alnico magnet, which consists of an iron alloy combined with aluminum (Al), nickel (Ni) and cobalt (Co), copper, and sometimes titanium. Alnico magnets produce magnetic field strength at their poles as high as 1500 Gauss (0.15 Tesla), or about 3000 times the strength of the Earth&#39;s magnetic field. Anisotropic alloys generally have greater magnetic capacity in a preferred orientation than isotropic types. Alnico&#39;s permanence (Br) may exceed 12,000 G (1.2 T), producing a strong magnetic flux in closed magnetic circuit. Other permanent magnets are known for use in sticky devices including, but not limited to, ceramic magnets, SmCo magnets and NdFe magnets. In embodiments of the present invention, a selectable sensitivity may be 1000-6000 Gauss and fields above 6000 Gauss. 
     Forensically, it is possible to track the source of a sticky device if recovered, even if recovered in pieces after it has exploded, from the composition of the magnet. A recovered portion of a magnet may be reverse-engineered to determine its original size, its gaussian output, its metallic or ceramic composition and from these factors, its origin or location of manufacture. It is demonstrated that a portable embodiment of the invention such as a wand or mirror embodiment may be used to discover magnetic bomb fragments at an explosion site. 
     These and other features of embodiments of a hand-held and/or embedded device and/or above an open box-like or reverse U-shaped frame and/or cylindrical or paddle-shaped wand for detecting sticky devices with minimal harm to the user using Hall-effect sensor circuits will be discussed herein with reference to the drawings and the following detailed description thereof. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  shows a line drawing of a user of a prior art pole-mounted mirror for manually determining whether the undercarriage of a vehicle  150  exhibits unusual characteristics from a visual observation;  FIG. 1B  shows a similar line drawing of a prior art extendible telescoping pole-mounted mirror for visually observing the roof of a vehicle such as a panel van or other truck which is taller than the user. 
         FIG. 2A  shows a line drawing similar to that of  FIG. 1A  to show an extendible pole-mounted mirror that may be retrofitted to incorporate one or more magnet detectors or sensors  210  at its center and perimeter sensors  211  about the perimeter of the mirror (Hall-effect, magnetometer type or hybrid) which may report the presence and location of a magnetic field to a display portion  220  mounted on the pole per  FIG. 2B  to correspond to the arrangement of the sensors  210 ,  211  on the mirror;  FIG. 2B  shows a display of LED&#39;s that may correspond to the arrangement at the center and mirror perimeter to show how a real-time display  220  constructed, for example, of light emitting diodes may correspond one to one with the sensors  210 ,  211  and so display a real-time location of a sensed magnet to a user. 
         FIG. 3A  shows a line drawing of a first, for example, cylindrically shaped wand embodiment  300  of a magnet detector that may be used to pass under, over, around and inside a vehicle to detect magnetic fields.  FIG. 3B  shows a line drawing of a second wand embodiment more shaped like a paddle. A plurality of, for example, an array of 3×6 Hall-effect sensor magnetic field detector circuits are mounted on one side of the bottom paddle portion of wand  300 , for example, back-to-back, multiple axis or single Hall-effect sensor circuits or other circuits as will be discussed further herein, and associated and corresponding light emitting diodes, also, for example, in a corresponding 3×6 array, are shown proximate to a handle portion actuated whenever a corresponding magnetic field sensor is activated (individually in LED groups of two or three or four) so that the user may visibly see an outline of a detected magnetic field via the actuated light emitting diodes mounted proximate a user handle portion as a display portion. Preferably, Hall-effect transducers having a two or more axis sensing feature and mounted back-to-back to actuate regardless of field polarity are used in the magnetic field sensors. 
         FIG. 4  represents a line drawing of a vehicle passing over a road mounted band sensor, the sensor system comprising a plurality of sensors mounted on the band and also comprising flexible, hollow pole mounted sensors for reaching into vehicle wheel wells for passively detecting the presence of a magnetic field and operating a corresponding, for example, light emitting diode display, not shown, at a proximate or remote user station for signaling the presence of a magnetic field, for example, of a sticky device located in a wheel well, different vehicles having different magnetic field signatures. A stored magnetic field signature may be subtracted from a sensed signature and the display show a magnetic field of potential concern. Per  FIG. 10 , also, a camera system  1020  may be used to capture images of an undercarriage of the passing vehicle, and image segmentation analysis may be used to distinguish a visible anomaly automatically. When a convex mirror system is used a known convex to flat image conversion algorithm may be used to convert a convex mirror image to a flat image. 
         FIG. 5  represents a line drawing of a vehicle passing through a plurality of magnetic field sensor-equipped soft cloth strips of a U-shaped frame  525  also having horizontal and vertical, vehicle side and bottom, hollow, flexible pole-mounted sensors. These and a road mounted sensor  400  of  FIG. 4  wipe over the sides, bottom and top of a vehicle and, in a similar manner to that of the embodiment of  FIG. 4 , known magnetic field signatures may be subtracted from sensed signatures at predetermined locations and a display shows a magnetic field of potential concern and/or cameras are used to detect visible anomalies automatically. 
         FIG. 6  represents a soft iron core magnetic field sensor which may become magnetized in the presence of a magnetic field and detected via the a winding at magnetic field sensor  630 ; a display or LED&#39;s may be lit to show the detected magnetic field. 
         FIG. 7  represents an electrical circuit block diagram of a linear Hall-effect sensor  705  with coarse and fine grain tuning for detecting different Gaussian levels as well as bias and temperature compensation for detecting a magnetic field. 
         FIG. 8  represents a simple diode circuit for use with the circuit of  FIG. 7  whereby the Hall-effect sensor  705  is now represented as Hall-effect switch  805  for operating, for example, a light emitting diode D 1  to signal the presence of a magnetic field when the switch is switched on. 
         FIG. 9A  represents a plurality of Hall-effect sensors per  FIG. 7  or  8  connected by a bus and each having a microcontroller where the sensors may trigger at different values of magnetic field strength in gauss in order to detect a range of different magnetic fields and magnets, for example, ceramic and AlNiCo magnets or a row of sensors per  FIG. 3A ,  3 B,  4  or  5  among others;  FIG. 9B  shows an exemplary circuit comprising a single Flail-effect sensor and an operational amplifier and a light emitting diode indicator for the actuation of the sensor; and  FIG. 9C  shows an exemplary circuit of two back-to-back Hall-effect sensors and an operational amplifier and two light emitting diodes to increase sensitivity and range to be N or S polarity independent. 
         FIG. 10  represents a schematic block diagram of a magnetic field sensor system having a plurality of means for detecting a magnetic field or otherwise detecting an anomaly including but not limited to flexible, hollow pole-mounted or flexible strip mounted sensors, sensor arrays and the like, radio frequency detection for detecting transmissions to/from a sticky device, further including, for example, a black scale or chromatic still or video camera for detecting color distinctions in a typically black vehicle undercarriage that may indicate the presence of a sticky device, a road mounted sensor or surrounding coil similar to that depicted in  FIG. 4  plus soft cloth strips for the top and side flexible pole mounted Hall-effect sensors per  FIG. 5 , magnetometers, a light source, if required, for the camera and the user and a typical mirror per  FIG. 1  or  2 , a GPS system of the vehicle or a moving sensing system such as a wand; an accelerometer to detect speed; a processor may receive vehicle identity input via an input device and communicate with a remote database or maintain known vehicle magnetic signatures and vehicle images in local memory and processor received data and display an output indicating a possible magnetic field of potential concern on a display responsive to an analysis of all input data about a scanned vehicle automatically. 
         FIG. 11A  shows an experimental prototype pole-mounted mirror on wheels with a handle and with three Hall-effect sensor circuits mounted on the mirror, each having their own power indicating LED and sensing LED indicators of a magnetic field, the center of the mirror having been drilled for passing wires and having a hollow extendible pole;  FIG. 11B  shows the experimental prototype from the rear of the mirror showing the wiring of the three Hall-effect sensor circuits;  FIG. 11C  shows the handle portion of the prototype mirror assembly where a battery power supply and on/off switch may be located; and  FIG. 11D  shows the prototype mirror assembly being placed in the vicinity of a mock sticky device magnetically attached to a vehicle undercarriage wherein, due to the proximity of the sticky device to one of the three Hall-effect sensor circuits both a power indicator LED and a Hall-effect sensor magnetic field sensor LED are both illuminated. 
     
    
    
     DETAILED DESCRIPTION 
     Referring now to the drawings  FIGS. 2A-5  and  10 , the details of specific example embodiments are schematically illustrated. All the embodiments of  FIGS. 2A through 5  may use one or more of the features shown and described by  FIG. 10 . For example, a wand or a mirror embodiment may have an RF communications interface and/or an input keyboard. A user could manually enter a VIN number by an input keyboard so that collected data could be matched to a particular year, make, model of vehicle and magnetization signature or camera images retrieved. An RF interface could pick up a Lojack car signal identifying the vehicle. A fob on a key chain must match a Lojack record in a hidden ear Lojack transceiver or the car is considered stolen. An intercepted Lojack communication could be sufficient to uniquely identify a vehicle having a Lojack feature. A car GPS system radio frequency transmission or on-board vehicle telecommunications or radio system may be received by a radio frequency communications interface to uniquely identify a vehicle. An RF communications transceiver of an embodiment could send collected data to a local or remote server and receive back vehicle magnetization signature, car portion images and so on. A vehicle as it uses a smart pass on a highway at a toll booth could be correlated to year, make and model of vehicle for the smart pass for retrieving images and magnetization signature. RF identification is typically used for truckers as they go through weigh stations and border crossings so the RFID could be matched with a particular truck and cargo trailer and so identified. After  FIG. 2A  through  FIG. 5 , potential circuits are shown in  FIGS. 6-9A ,  9 B and  9 C which may comprise novel arrangements for detecting the presence of a magnetic field of potential concern and displaying an output reflecting same.  FIG. 10  provides a schematic block diagram of an embodiment of a magnetic field sensor system combined with other anomaly detection systems which may utilize a plurality of different means taken, for example, from  FIGS. 2A-5  and enhanced for detecting a magnetic field of potential concern and discriminating a sensed field from expected magnetic fields by storage and comparison with known magnetic vehicle signatures automatically. These embodiments are not intended to be limiting and may be mixed into various embodiments according to specific applications, for example, at entrances to buildings, border crossings, toll booths and hand-held sensors that may be used by vehicle users.  FIGS. 11A ,  11 B,  11 C and  11 D show the manufacture of a prototype mirror assembly equipped with three Hall-effect sensors and its demonstrated testing with a simulated sticky device attached by a magnet to a vehicle undercarriage. 
     Referring to  FIGS. 2A and 2B , there is depicted in  FIG. 2A  a handheld mirror assembly  100  (for viewing underneath a vehicle) which may comprise an extendible pole  218  known in the art adapted to further comprise a magnetic sensor system and/or a camera system with wheels (not shown). Extendible pole  218  may be manually extendible (for example, telescoping) and hollow for internal electrical wiring from mirror  250  to a power supply and switch near the handle portion. A distal mirror portion  250  may be used for viewing the top of a vehicle with the mirror  250  on the end of the handheld, extendible rod or pole  218 , a user using two hands for lifting and turning the assembly by extended pole  218 . A Hall-effect sensor circuit or plurality of Hall-effect sensors  210  such as two sensors back to back may be imbedded behind the center of the mirror. In a hybrid embodiment, any sensor  210 ,  211  may be a magnetometer circuit per  FIG. 6  requiring no degaussing when used with a proximately spaced Hall-effect sensor. By “embedded behind” is intended the drilling, for example, of a glass or plastic mirror so that the Hall-effect sensor circuit wiring may pass through the mirror and be channeled through the hollow of the extendible pole  218 , for example, to a power on/off switch where a battery power supply may most conveniently located near the handle portion along with a light source and camera requiring power to capture a visual image from the mirror of a vehicle portion. Moreover, it has been experimentally determined that a typical range of operation of a Hall-effect sensor circuit is approximately less than six inches or in the range of over 10 cm so that a typical mirror diameter may be twelve to eighteen inches. To locate a magnetic field, a plurality of Hall-effect sensor circuits  211 - 1  to  211 - 6  are shown mounted about the periphery of a mirror, for example, approximately about nine inches apart and from the center of the mirror  250  if the range of a Hall-effect sensor is typically about less than six inches. If greater resolution is desired, additional sensors may be placed to cover practically the entire area of the mirror. Continuing this hypothesis, the diameter of the mirror  250  would be approximately twelve to eighteen inches, and there may be approximately six or seven sensors total, including the center sensor  210 . Generally, for vehicle scanning, it is suggested that an appropriate range in mirror diameter be from approximately eight inches to twenty-four inches. With a convex shape, the mirror may cover at least half a vehicle width of an undercarriage. As a Hall-effect sensor range or sensitivity improves, a plurality of sensors mounted about the periphery of the mirror  250  or between the periphery and a circuit at the center of the mirror will permit improved location finding of a smaller valued suspect magnetic field. If larger or flatter mirrors are used, more sensors may be located at an intermediate circular position between the mirror center and the perimeter. 
     Per  FIG. 2A , a typical mirror pole assembly is retrofitted to comprise at least one magnetic field sensor per one of circuits and systems  FIGS. 6-10  (i.e. one centrally located sensor or multiple axis or back-to-back dual polarity sensors) which, when actuated, causes a display  220  per  FIG. 2B  to indicate the presence of a magnetic field, for example, a light emitting diode display and outline its location and shape. Preferably, the one magnetic field sensor is at least a two-axis or three-axis Hall-effect or other sensor with structures at 90° rotation to one another or two Hall-effect sensors mounted back to back on a single die so as to be able to measure any polarity magnetic field to which it becomes proximate at greater range. Embodiments of Hall-effect sensors preferred in any of the depicted embodiments are two-axis or three-axis sensors. Moreover, two Hall-effect sensors may be placed back to back to improve sensitivity and range of field detection regardless of field polarity. During a visual inspection of the undercarriage of the vehicle or other area via light source/chromatic camera  215 , a positive reading of the sensor voltage in one or the other or both (or three) axes may indicate the presence of a magnet, prompting a closer examination. Image segmentation analysis may compare a known vehicle portion image with a suspect vehicle portion image to detect an anomaly. The traditional flashlight and mirror with at least a central magnetic sensor may be used in the indicated site of the magnetic field by a user who may be a security officer or a vehicle user. These may be enhanced by a camera for capturing images or by reference to a database of images or magnetic signatures of vehicles by vehicle identity for scanning the vehicle before the vehicle is moved. The mirror may be convex and cause a distorted camera image. Known convex to flat image algorithms may be used to correct a convex image that may cover as large a distance as fifteen feet to a flat image. In accordance with an enhancement, vehicle identity information may be entered by an input device such as a keyboard  1008  ( FIG. 10 ). One or more identified undercarriage vehicle portion images or different vehicle portion images may be obtained remotely and/or stored locally in processor memory  1005  or in memory of a remote server (not shown) reached via communications interface  1002  for the identified vehicle. A chromatic camera  215 ,  1020  may provide a single or video image of for example, the identified vehicle undercarriage under examination to a central processor  1000  ( FIG. 10 ). Using known image segmentation software, the retrieved vehicle image may be compared with the converted vehicle undercarriage under examination image and an unidentified shape located that is suspect. The operator of the  FIG. 2A  system may then move the mirror/magnetic sensor into proximity and better examine the suspect shape. As indicated above, a convex parabolic mirror may distort an image and even capture the entirety of an undercarriage and so a planar image restoration algorithm may be used by the central processor  1000  ( FIG. 10 ) so that the image segmentation algorithm may compare camera captured planar undercarriage image to stored planar identified undercarriage image. 
     According to  FIG. 2B , there is shown a display  220  that may comprise a plurality of LED or other known equivalent devices forming a pattern corresponding to the plurality of sensors  210 ,  211  at the center of and around the periphery of the mirror  250  for viewing the undercarriage, sides, roof, wheel well, engine compartment, interior or cargo area of a vehicle and obtaining an indication of a magnetic field of potential concern at an identified area of concern per the display  220  in combination with the mirror pole assembly of  FIG. 2A . While it is believed that magnetic devices may be more commonly affixed to vehicle sides, wheel wells and bottoms of vehicles, location identifying devices may be found adhering to the not typically visible roofs of vehicles, especially, trucks. 
     Consequently,  FIGS. 2A and 2B  depict embodiments of the handheld mirror of  FIG. 1A ,  1 B where an array of Hall-effect sensors are imbedded behind, in or on the surface of the mirror  250  and around its periphery and demonstrate that an embodiment of  FIG. 1A ,  1 B may be retrofitted to incorporate magnetic field sensing using Hall-effect sensor circuits and location of a suspect magnetic field (and, enhanced with a camera system, may detect a suspect shape not normally present on an identified vehicle). Sensor arrays, such as shown in  FIG. 2A  may illuminate a panel or display  220  consisting of the corresponding light emitting diodes (LEDs)  222  or other visual screen display ( FIG. 2B ) on which the shape of the magnet may be shown within the array of LED&#39;s and thus located when the magnetic device might not otherwise be easily seen). During a visual inspection of the undercarriage of the vehicle or other area, a positive reading of the Hall-effect sensor voltages may indicate the shaped presence of a magnet, prompting a closer examination, deactivation or removal of the device or, at least immediate movement of the vehicle to a safer location for professional removal. Camera enhancement provides improved suspect shape recognition regardless of magnet detection and may be utilized separately from magnet detection to detect suspect shapes via known image segmentation algorithms. 
     Referring to  FIG. 3A , there is depicted a first wand embodiment of a handheld device consisting of a wand  300  in which a linear array of for example, linearly arranged Hall-effect sensors  310  comprising, for example, a one by six array of back-to-back, multiple axis Hall-effect sensor circuits may be mounted in a line to the wand  300 . The wand is preferably light weight, for example, consisting of plastic and be operable using one hand via handle portion  325 . In an alternative paddle-like embodiment ( FIG. 3B ) having a flat surface, for example, three linear rows of six Hall-effect sensors each (preferably at least two or three axis sensors and/or two sensors mounted back to back)) are embedded on a wand surface  310 , for example, spaced less than eight inches apart facing the object to be inspected. On the top of the wand, proximate the handle, corresponding LED&#39;s  320  or other visual screen displays may directly correspond to the location of the, for example, 3×6 array of Hall-effect sensors  310 . The operator of either wand device  300  may move the wand along a surface of a suspect vehicle, interior, exterior, undercarriage or roof (including engine compartment or trunk) where a sticky IED, container or location finder may be affixed to an inside (or outside) surface of the vehicle, may actuate the sensor arrays and vary the intensity and number of the LED&#39;s actuated as the sensor becomes closer to the suspect magnetic field, thus showing the outline of a magnet affixed to an explosive device or location finder or container (drugs, key, etc.). In this embodiment, a linear array of, for example, five or six back-to-back, multiple axis Hall-effect sensors  310 - 1  to  310 - 8  (eight shown) may be placed at a distal end of the wand ( FIG. 3A ) while a corresponding LED or other display  320 - 1  to  320 - 8  of sensor actuation may be located at a proximal end just below the handle portion  325 . This embodiment may be especially suitable for reaching areas of a vehicle such as a wheel well, engine compartment or vehicle interior that a mirror assembly may not reach. 
       FIG. 3B  shows a line drawing of a second wand embodiment more shaped like a paddle. In a prototype embodiment, the paddle wand has been used to selectively measure a magnet (which may be attached to a sticky device) having a field of strength 3000 Gauss at six inches. With all embodiments described herein, a selectable range of field strength may be incorporated into the various embodiments by for example, using more sensitive Hall-effect sensors, the coarse/fine tuning circuit of  FIG. 7  and/or selectively actuating the more sensitive versus less sensitive sensors with a selectable switch or, in an alternative embodiment, using a potentiometer to vary the range of voltage applied to a Hall-effect sensor circuit to decrease or increase sensitivity by changing an applied DC voltage level. 
     The handheld wand  300  of  FIG. 3A  or  38  may also be used to assess the presence of magnetic materials in post-blast detonation of IED&#39;s to determine if the debris in a field area contains remnant portions of a magnet from a sticky IED. This material could be more easily collected without contamination once located. Furthermore, once recovered, the piece of magnet may be forensically analyzed for its original composition, for example, AINiCo or ceramic, its original size, its original properties and potentially its original source or manufacturer may be identified. In either embodiment, a GPS sensor and an accelerometer may be mounted, for example, toward the distal end (not shown) to capture the first and second wand embodiments in three dimensional space at a particular location and having a particular speed determined by the operator. The location and speed may be communicated by an RF communications circuit (not shown) for communication to a remote server by a communications interface  1002  per  FIG. 10 . The GPS unit may track the location of detected magnetic fragments of an IED after a bomb explosion. While typically intended to be portable and carried by the handle portion, the wand or linear array embodiments may be also formed as a part of a structure such as the frame structure  525  ( FIG. 5 ) to be discussed further herein for scanning the sides, top and bottom of a vehicle. 
     Referring to  FIG. 4 , depicted is an embodiment of a road mounted magnetic field sensor device  400  consisting of a linear array of Hall-effect sensors or other magnetic field sensor  410  such as a soft iron core and associated coil. As discussed above, preferably two-axis or three-axis and/or back-to-back Hall-effect sensors are used to form the linear array to increase range and sensitivity. In addition, in order to reach under wheel wells and into engine compartments, a plurality of linear motor driven, vertical, flexible, hollow pole-mounted Hall-effect sensors  411  may be provide, for example, in the vicinity of a wheel well, engine compartment or other recessed location of a vehicle. The flexible, hollow pole-mounted Hall-effect sensors comprise an extendible, hollow pole which may be strong but hollow to permit electrical connection to a processor  1000  per  FIG. 10  along with the road-mounted sensors  410 . These parallel inputs may be connected and uniquely identified to the processor in a conventional, known manner. Motors for vertically moving the pole mounted sensors  411  are not shown but the poles may be moved to an appropriate vertical height according to a vehicle identity input per keyboard/input device  1008  ( FIG. 10 ). The linear sensor array  410  and vertical pole mounted sensors  411  may be embedded on the road surface and the poles facing and facing upwards and being bendable under the object or vehicle  405  to be inspected, for example, at a border crossing or building entrance. The array  410 ,  411  can be permanently affixed to the pavement and comprise a “bump” or mounted on a flexible and durable strip that can be temporarily affixed to the pavement. As will be further described herein, known vehicles as they cross a magnetic field sensor may exhibit known or expected magnetic field signatures as the vehicle crosses the sensor  400 . In one embodiment, per  FIG. 10 , a user enters the make, model and year of the vehicle via input device  1008  in order to obtain a known or expected magnetic field signature (as well as an undercarriage camera image for image segmentation analysis for anomalies). Such a magnetic, signature may be subtracted from the results obtained from road mounted sensor  400  and provide a display and location of a suspected magnetic field. Also, a road mounted sensor  400  may be enhanced by one or more light sources and cameras (not shown) for imaging an undercarriage and exposed area such as an engine compartment and comparison to known images retrieved from an image database via image segmentation. 
     Referring to  FIG. 5 , there is depicted an embodiment of a vehicle roof inspection sensor system comprising a linear plurality of flexible strips, not unlike that found in a car wash, mounted to a reverse U-shaped frame  525 . The flexible strips  500  contain sensors at the ends such as Hall-effect sensors for scanning a vehicle from a frame, doorway, or interior space. Again, preferably two-axis or three-axis and/or back to back Hall-effect sensor circuits are used at the vehicle roof end of each flexible strip. Electrical wiring may be flexible and run from the sensors up the flexible strip, through the frame  525  to the processor  1000  of  FIG. 10 . Moreover, frame-mounted, horizontal, flexible pole mounted sensors  510 - 1  to  510 -N may sweep the sides of a vehicle as it is pulled by a motor-driven vehicle movement system  560  (optional) such as one used at a car wash. The sensors may be uniquely identified and their output data may be multiplexed and sent as a serial input to the processor by a multiplexer not shown or sent in parallel by wire or secure radio frequency transmission (not shown). 
     Also optional, the vehicle driver may be invited to await inspection in their own driver bomb-proof building  575 . (It is conceivable that the vehicle driver may be wearing a bomb and the building  575  be not only bomb proof but contain bomb detection equipment). The vehicle inspector may be located along with the processor  1000 , keyboard  1008 , display  1010 , communications interface  1002  to a remote server and image or magnetic signature database and other items depicted in  FIG. 10  in check-point bomb proof building  550 . In this embodiment, the vehicle may be pulled through the frame  525  by a chain drag system and confining lengthwise track  560  (similar to those used in a car wash) under control of the system operator. In an alternative embodiment, the depicted vehicle may be driven by its operator through this frame  525  containing the flexible cloth strips, horizontal sensors  510  and underground sensor and vertical poles system  400 . The road-mounted sensor system  400  may be used to swipe and scan the undercarriage as the vehicle moves through frame  525 . Embedded on the ends of the flexible strips  500  are, for example, two axis or three axis Hall-effect magnetic field sensors or back-to-back Hall-effect sensor pairs that can detect the presence of a magnetically affixed explosive, location finder or container device as the vehicle passes through the frame  525 , thus allowing the sensors to come into contact as the vehicle brushes through these flexible strips and horizontal detectors  510  and road-mounted sensor system  400 . As with the embodiment of  FIG. 4 , a known vehicle signature or image can be retrieved from memory for comparison with a sensed magnetic field signature or images and suspected areas of the vehicle may be identified by means of a camera and light source for the top, sides and undercarriage (not shown). 
     An important factor in using hidden detectors for detection of magnetically affixed devices is secrecy of the security inspections (for example, per  FIGS. 4 and 5  or a combination thereof). For example, the underground system  400  may be practically invisible in a road surface and the frame  525  may be built into a fortified building entrance or portico area (not shown). Hidden surveillance increases the chance of detecting these explosive and tracking devices. By not making the surveillance methods obvious, the detection of careless or sloppy affixed devices by potential terrorists may have a higher probability of success. Complete screening may be done on large numbers of vehicles passing through public and private areas, over border crossings, toll booths on interstate highways or at building entrances. 
     It is contemplated and within the scope of this disclosure that data from the detectors, location (UPS  1032 ), time of day, and/or video images of vehicles being inspected may be gathered, transmitted and stored for future reference by police authorities, the military, and/or government anti-terrorist agents via any of the embodiments of  FIG. 2A  to  FIG. 5 . Real time correlation of sensor data location, time, and/or video images may also be useful for tracking specific incidents, crisis situations and identification of security threats. The sensor information may be sorted into bundles of data, types of data, attributes of data, etc. along with the location and identity of the sensor system, for example, per  FIG. 4  or  FIG. 5  from which data is collected for an identified vehicle and transmitted via a communications interface  1002  ( FIG. 10 ) for remote analysis at a remote location or cloud server. 
     Any of the aforementioned detection devices may be located at, by way of example, and not intending to be limiting: loading docks, ferry boat docks and ramps, bus terminals, air ventilation ducts, building entrances, parking garage access gates, mechanical access tunnel entrances, moving sidewalks, elevators, escalators; ingress and egress points of buildings, trains, subways, airports, buses and bus stations, etc. 
       FIGS. 6-9C  show a plurality of sensor circuits for suspect magnetic field sensing. Referring to  FIG. 6 , there is shown a block schematic diagram of a soft iron core magnetic field sensor for use in detecting magnetic fields produced by, for example, sticky IED&#39;s, containers and location finders. Sensor circuit  600  represents a soft iron core magnetic field sensor  620  which does not require degaussing if it is used in combination with a Hall-effect sensor circuit at a predetermined distance such that the iron core  610  may falsely trigger an adjacent Hall-effect sensor per, for example, one of  FIG. 9B  or  9 C. On the other hand, if the Hall-effect sensor and the magnetometer of  FIG. 6  are used side-by-side, the soft iron core may be initially or periodically degaussed via a short duration A/C voltage produced via an A/C voltage generator. The circuit of  FIG. 6  is intended to serve as a circuit for use in a hybrid device with Hall-effect sensors spaced, for example, six inches away from the soft iron core  610 . Coil  620  may detect a magnetic field of suspect origin. In other words, the closer soft iron core  610  may come in proximity to a magnetic field by the square of the distance, core  610  may become magnetized in the presence of the magnetic field. The magnetic field may be detected via the winding  620  at magnetic field sensor  630 . Differential amplifier output  625  receiving input from core  610  wrapped by coil  620  is output to A. C. amplifier  645  whose output is rectified at active full wave rectifier  650  and is one output, along with the shared output of differential amplifier  625  and sensor  630  as an input to logic/controller  625  for lighting display  640 . Magnetic field sensor  630  as well as rectifier  650  reports to logic circuitry or controller  635  which, in Mm may actuate a display  640  or LED&#39;s lit to show the presence of the detected magnetic field. 
     An alternative embodiment may comprise a square or other shaped core  610  that may be configured to receive a first winding  620  as shown so that the polar positions of the magnet are left and right, north and south. A second winding may be wound over or through the first winding  610  so as to be wound at 90 degrees or orthogonal to the first winding  610 . Core  610  may be magnetized to have magnetic poles facing up and down. If the core  610  is magnetized up and down and winding  620  is used to detect the magnetic field, it may fail to detect the orthogonal magnetic field, but the second winding will detect it. The first and second windings then will detect either polarized orthogonal magnetic field caused in core  610  by approaching, for example, a permanent magnet of a sticky device. 
     A hybrid embodiment is also possible. In such an embodiment, one or more iron core magnetic sensors ( FIG. 6 ) may be used, for example, on a mirror or in a wand embodiment or other embodiment where the iron core magnetic field sensor may detect a magnetic field that a Hall-effect sensor does not. In such an embodiment, the Hall-effect sensor (for example,  FIG. 9B  or  9 C) will not falsely trigger when the iron core magnetic sensor becomes magnetized by the magnetic field it is detecting. Using such a circuit as the circuit of  FIG. 6  with a Hall-effect sensor circuit spaced from it as, for example, per  FIG. 9B  or  9 B, it may not be necessary to sequentially operate the Hall-effect sensors and the spaced iron core magnetic field sensor. Degaussing the iron core magnetic field sensor iron core may not be required unless the Hall-effect sensor is extremely sensitive. If degaussing is required, as is known in the art with an alternating current pulse, a length of time may be required to degauss the iron core magnetic field sensors so a magnetized iron core does not falsely trigger a nearby or highly sensitive Hall-effect sensor. 
       FIG. 7  represents an electrical circuit block diagram of a linear Hall-effect sensor  705  with coarse and fine grain tuning as well as bias and temperature compensation for detecting a magnetic field. Hall-effect sensor  705  connected to auto-nulling network  720  may be linear or non-linear in nature but operates at a predetermined level of field strength measured in gauss and preferably comprises a two axis, three axis sensor and/or back-to-back sensors. The output of sensor  705  may be provided to anti-nulling network  720  to compensate for selectable field sensitivity and detection ranges in actuation of switch  705 . For example, coarse grain amplifier  730  may provide a coarse grain setting for switch  705  actuation and fine grain amplifier  730  may provide a finer grain setting for actuating switch  705  in the presence of a magnetic field. An offset digital to analog converter may provide a constant offset depending on, for example, known characteristics of a vehicle to be measured that may be offset from detected readings at adder  750 . The output of adder  750  may be clamped at clamper  755  and the output driver  760  produce an analog output for processing as will be described in conjunction with  FIG. 10 . A non-volatile memory may be loaded with predetermined bias levels and temperature characteristics of magnets to be detected and characteristics of the particular sensor  705  used. In this manner, non-volatile memory  710  may provide a clamping output to clamp  755 , an offset to offset DAC  745  and a bias and temperature compensation value to sensor  705 . 
       FIG. 8  represents a simple diode circuit for use with the circuit of  FIG. 7  whereby the Hall-effect sensor  705  is now represented as Hall switch  805  for operating, for example, a light emitting diode D to signal the presence of a magnetic field when the switch  805  is switched on. A 1 k ohm resistor R 1  is shown by way of example only and is not intended to be limiting. The resistance value, if any, is determined by the current needed to light diode D 1  and the characteristic output of switch  805 . 
       FIG. 9A  represents a plurality of Hall-effect sensors per  FIG. 7  which may be used with the LED displays of  FIG. 8 . The sensor circuit is connected by a bus to bus master  910 . Each Hall sensor circuit  900 - 1  to  900 -N may comprise a sensor  905  and associated microcontroller  910 . The sensors  905  may trigger at different values of magnetic field strength in gauss in order to detect a range of different magnetic fields and magnets, for example, ceramic and AINiCo magnets among others. They may trigger in a line or as an array per any of  FIG. 2A ,  2 B,  3 ,  4  or  5 . For example, a typical remnant induction or flux density B present in a closed ring in a saturated state for a typical ceramic magnetic may be 3850 Gauss. For an AINiCo magnet, a range in B may be from 8,200 to 12,800 Gauss and for NdFeB up to 13,500 Gauss. Hall-effect sensors are on/off binary devices operative at a relatively high sensor on point and to turn off at a relatively low level of gauss. Magnetic field strength diminishes with the square of the distance. So the closer any magnetic field detector is to a magnet, the more likely the detector will turn on. Temperature also impacts both the residual level of gauss in a permanent magnet and also impacts the characteristics of the field detector. Consequently, the circuit of  FIG. 7  advantageously compensates for temperature and, when formed into an array of different sensors of varying sensitivity, the circuit of  FIG. 9A ,  9 B or  9 C when utilized with the circuits of  FIGS. 6 ,  7  and  8  (to display an output) may provide identification of magnetic field strength, magnet type and size. Forensically, it may be possible to reconstruct a magnet from a discovered fragment and even, in combination with data of its alloy mixture, determine the source of its manufacture of the magnet. 
       FIG. 9B  shows an exemplary circuit comprising a single Hall-effect sensor and an operational amplifier and a light emitting diode indicator for the actuation of the sensor. This circuit is exemplary only as many different operational amplifiers. Hall-effect sensors or light emitting diodes may be utilized to replace those shown. One input of a Hall-effect sensor is, for example, an optimal 7.2 volts for maximum range. Changing the input voltage is one way to change the range or sensitivity. A first output to an operational amplifier is provided directly to an operational amplifier and the other output is provided to variable potentiometer R1 and then to the operational amplifier. The resistor R1 (which may be a potentiometer) cuts the supplied power to a level for maximizing sensitivity and/or providing a selectable range of the Hall-effect sensor.  FIG. 9C  shows an exemplary circuit of two Hall-effect sensors arranged back to back and connected in parallel with one another and providing inputs to an operational amplifier and two light emitting diodes to increase sensitivity and range, and which will light notwithstanding the polarity of the suspect magnetic field or direction. One of the Hall-effect sensors will detect the field if the other does not. In a test of such a circuit, a back-to-back Hall-effect circuit may comprise back-to-back A1301 Hall-effect sensor integrated circuits formed as a 3-pin SOT23W for surface mount circuit. These have a sensitivity of 2.5 mV/G. With such a circuit, a range of approximately six to seven inches for detection of a typical magnet was achieved. An A1302 circuit has an improved sensitivity of 1.3 mV/G and may, if tested back-to-back, achieve a much larger, perhaps double range of detection of twelve inches. So selectable ranges are possible by using A1301&#39;s and A1302&#39;s in selectable arrangements. These circuits are available from Allegro MicroSystems LLC of Worcester, Mass. 
       FIG. 10  represents a schematic block diagram of an enhanced magnetic field sensor system having a plurality of means for detecting a magnetic field or locating a suspect shape by known image segmentation algorithms. These magnetic field sensors may include but are not limited to radio frequency (RF) detection  1060  for detecting transmissions to/from a sticky device or suspect shape. It is known that radio frequencies such as a cell phone signal may be utilized to detonate an IED. Moreover, periodic RF signals from the IED may indicate to a controller that the device is alive and functioning. Thus, RF detection  1060  may be a very useful adjunct to magnetic field detection. Further, for example, a black scale or other chromatic camera  1020  may detect and amplify via amplifier  1015  color distinctions in a typically black vehicle undercarriage or other vehicle anomaly. These color distinctions may indicate the presence of a sticky device or suspect shape, not normally present for an identified vehicle for further investigation. Also, as suggested above, planar image translation may be performed if for example, an image is captured by a parabolic mirror. Image segmentation algorithms known in the art may be utilized to segregate a suspect portion of an image from a known image of an identified vehicle. The input from the camera is fed to processor  1000  which receives magnetic signal indications electrically in series as a single multiplexed transmission or in parallel, radio frequency and video inputs from, for example, a road mounted sensor or surrounding coil  1025  similar to that depicted in  FIG. 4 , the camera  1020 , RF detector  1060 , the soft cloth strips for the top per  FIG. 5 , the flexible pole mounted sensors of  FIG. 4  or  FIG. 5 , the Hall-effect sensors  1030  per  FIGS. 7-9 , soft iron core sensors per  FIG. 6 , known magnetometers, a light source, if required, for the camera  1020  and a typical mirror per  FIG. 1  or  2 . The camera output may be amplified, if necessary, by amplifier  1015  toward processor  1000 . Flexible, hollow, for example, telescoping poles and motors  1022  (horizontal or vertically rising) may be driven to extend or retract pole sensors once vehicle identification is input to processor  1000  by input device  1008  to place vertical pole sensors of system  400  or horizontal pole sensors  510  proximate the vehicle under examination. Hall-effect sensors  1030  or magnetometer-type circuits  1035  may be used individually or as pluralities in lines or arrays or in a hybrid embodiment comprising both types of field sensors. Further inputs to processor system  1000  may comprise GPS input  1032  and accelerometer input  1028 . A GPS input may be provided from a vehicle under inspection, from a location of a sensor system in connection with vehicle location GPS data received via RF detection  1060  to determine specific sensor location and comparison to specific vehicle location data. An accelerometer  1028  may provide an input as to sensor velocity or, via an RF detector  1060 , vehicle speed in relation to sensor system location. For example, the velocity and location of a wand  300  embodiment may be determined in relation to the velocity and location of a vehicle. Processor  1000  may maintain known vehicle magnetic signatures and vehicle images in memory  1005 . Processor  1000  may receive or transmit vehicle data or retrieve or transmit image or magnetic field data via communications interface  1002 , process the data via non-volatile memory signatures and image inputs for make, model and year of vehicle entered via input device or keyboard  1008  or determined by signature and display an output indicating a possible magnetic field of potential concern on a display  1010 . An AC/DC power source  1050  provides power to any device requiring power, for example, AC degaussing power for degaussing a soft iron core sensor per  FIG. 6  or DC power for Hall-effect sensor circuits and diodes and the like. Also shown are a conventional mirror  1045  and light source  1040  for visual or camera  1020  inspection. 
     In a further enhanced embodiment according to  FIG. 10 , the accelerometer  1028  and a GPS system  1032  may be used on the vehicle or on the scanning embodiment such as a wand or mirror assembly in order to compare three-dimensional space location of such a scanning assembly in relation to a three dimensional image of an identified vehicle. Use of vehicle location GPS and accelerometer data and scanner data may likewise be useful in the embodiment of  FIG. 5  for locating a suspect magnetic device or suspect shape in combination with device mounted GPS and accelerometer data as the vehicle passes through the frame. 
     Prototype Mirror Assembly Using Hall-Effect Sensor Circuits 
     Referring now to  FIGS. 11A-11D , a prototype Hall-effect sensor mirror assembly has been constructed from an off-the shelf mirror assembly on wheels per  FIG. 1A  by retrofitting the assembly with three Hall-effect sensor circuits mounted at the center and to each side of the center at the periphery of the mirror which measured eighteen inches in diameter. The inventors first experimented with voltage level in order to optimize the range of magnet detection of a KEYES KY-024 Hall-effect sensor circuit, commercially available from electronic supply outlets and manufactured in Guandong, China. This circuit includes a commercially available 49E Hall-effect sensor and a LM398 operational amplifier and a diodes circuit that is very inexpensive. The result of testing suggests that for a voltage of 7.2 volts DC, the range of the magnetic field detection of the provided Hall-effect magnetic field sensor was on the order of 10 cm&#39;s. It is proposed that with a 9 volt battery that a commercially available voltage regulator or potentiometer may be used to drop the nine volts to the approximately 7.2 volts for maximum range or used to vary the sensitivity of field detection. 
       FIG. 11A  shows the retrofitted mirror assembly on wheels with a mirror  1110  on which are mounted three Hall-effect sensors circuits in a line. The center of the mirror  1110  was drilled using a 3/16 inch diamond drill bit using a Bridgeport Milling machine including a Sinpo XYZ Digital Read-Out system. The resultant aperture was sufficiently large to permit power wiring to pass to a KEYES KY-024 Hall-effect sensor/diode circuit available on e-bay and a number of circuit suppliers on the web and manufactured in Guandong, China. There are two LED&#39;s provided, one which activates when power is provided to the circuit and the other LED is actuated according to the received signal strength determined by the operational amplifier output from the Hall-effect sensor. This LED lights dimly when a weak field strength signal is sensed and brightly when a strong field strength signal is sensed by the Hall-effect sensor. 
     Pole  1118  may be hollow and extendible (for example, telescoping), but, in the prototype comprised two pieces to extend to maximum length. The mirror assembly was equipped with wheels but was sufficiently light so as to be liftable using two hands above a vehicle roof. The lower piece was hollow and allowed power signal wiring to pass from the bottom of the mirror half-way up the pole. A flashlight or camera or both holder is shown provided at a handle end. A battery power supply and a power on/off switch may be installed into the prototype at the handle end. 
     Referring to  FIG. 11B , there is seen the reverse side of the mirror  110 . Power wiring is shown to each Hall-effect sensor circuit  1120 - 1 ,  1120 - 2  and  1120 - 3 . The power supply cord is seen at top going up the pole of to the handle area. The drilled hole for the circuit  1120 - 2  cannot be seen because it is underneath the mirror mount. The under-assembly wheels can be seen at top. If the mirror were not made of glass, a lighter weight plastic mirror may be substituted. For example, a convex All Industries, Chicago, III., SeeAll brand PLXO18 circular acrylic heavy duty mirror may cover an area up to 15 feet and so be sufficient for viewing an entire undercarriage of a typical vehicle. The extensible pole  1118 , attached to such a mirror, may be hollow and manually lengthened so that the entire assembly could be easily lifted by a user to view a roof of a vehicle and locate a suspect magnetic field on a vehicle roof using two hands. 
     Referring to  FIG. 11C , a battery supply and power switch are shown being attached to the handle end of the prototype mirror assembly. The KY-024 Hall-effect sensor circuits may be seen on 18 inch diameter mirror  1110  as circuits  1120 - 1 ,  1120 - 2  and  1120 - 3 . The KY-024 Hall-effect sensor circuit comprises a circuit similar to that of  FIG. 9B  except that it also includes an extra LED that indicates when power is supplied to the circuit. The three sensor circuit sensing LED&#39;s simulate a separate LED display  220  where the LED&#39;s are located at corresponding locations to corresponding Hall-effect sensor locations as per  FIG. 2B . 
     Referring to  FIG. 11D , a simulated sticky IED was attached by a magnet to a metallic frame of an automobile vehicle just at the side to the undercarriage.  FIG. 11D  shows a reflection in the mirror  1110  that both the power LED and Hall-effect sensor LED1, LED 2 are brightly lit when the peripheral sensor is brought proximate the mock sticky IED mounted to the vehicle frame. Similarly, not shown, the center mounted sensor LED was lit and the third, peripheral LED sequentially lit and unlit when the mirror was moved sideways, back and forth, under the undercarriage where the simulated sticky device was placed. Thus, the prototype proves the concept that a plurality of Hall-effect sensors and LED&#39;s may be utilized to form a display showing, for example, an outline of a sticky LED or any other sticky device. This same Hall-effect sensor prototype may be adapted for use with a flexible vertical roof strip, a vertical pole mounted Hall-effect sensor circuit, formed into an array for a wand and so on in related embodiments including an enhanced embodiment per  FIG. 10 . 
     While embodiments of this disclosure have been depicted, described, and are defined by reference to example embodiments of the disclosure, such references do not imply a limitation on the disclosure, and no such limitation is to be inferred. All patents referenced herein and all articles and textbooks shall be deemed to be incorporated herein as to their entirety. The subject matter disclosed is capable of considerable modification, alteration, and equivalents in form and function, as will occur to those ordinarily skilled in the pertinent art and having the benefit of this disclosure. The depicted and described embodiments of this disclosure are examples only, and are not exhaustive of the scope of the disclosure. 
     REFERENCES 
     
         
         Ernesto Londoño, 2008, “Use of ‘Sticky IEDs’ Rising in Iraq: Magnetized Devices Cling to Undersides of Vehicles,” Washington Post Foreign Service, Thursday, Oct. 9, 2008. 
         Matthew P. H. O&#39;Hara. 2009. “Detecting Improvised Explosive Devices in Urban Areas,” US Navy, Wednesday, Apr. 1, 2009. 
         Edward Ranson, 2006 , Hall - Effect Sensors , Elsevier, 2006.