Abstract:
An interface module for interfacing on-board electronics in a vehicle with a radar device and/or camera. A plurality of data busses are configured for different signaling protocols, such as variable pulse width, pulse width modulated and ISO 9141. A data processor activates the data busses and selects the bus that is most compatible with the on-board electronics. Data is then received and translated to a form compatible with the radar device and/or camera. Typically, the data provided will be vehicle speed information which is used by the radar device to identify the best candidate in the radar Doppler return or is displayed with images taken by the camera. The speed information is also used to control the field of view of the camera, with wider angles of view used for lower speeds. Related methods are also disclosed.

Description:
FIELD OF THE INVENTION  
       [0001]     This invention generally relates to traffic radar. More particularly, this invention relates to a apparatus for interfacing on-board vehicular electronics with traffic radar and/or video surveillance systems.  
       BACKGROUND OF THE INVENTION  
       [0002]     Traffic radar devices are in widespread use to determine the speed of a target vehicle. Such radar devices transmit radar signals which are reflected by the target vehicle. The reflected radar signals are then processed to determine the speed of the target vehicle. These radar devices accurately determine the speed of a target vehicle if the radar device is stationary or if it is in a stationary patrol vehicle. However, if the radar device is in a moving patrol vehicle, the speed of the patrol vehicle must also be taken into account, such as by adjusting or correcting the speed of the target vehicle as determined by the radar device to account for the relative motion of the patrol vehicle.  
         [0003]     One of the common problems in moving police radar is the inability for the radar device to always correctly identify the correct ground Doppler return. Typically, the Doppler return when the radar device is in motion will consist of a very complex Doppler waveform. This complex waveform includes the Doppler return waveforms from stationary road side objects as well as the Doppler return waveforms from moving targets moving towards and/or moving away from the radar device. The radar device uses certain methods to overcome these complex waveforms and chooses what it thinks are the best candidate in the Doppler return waveforms. There are numerous conditions that can occur that may cause the radar device to misinterpret and to report an incorrect patrol speed. Common misinterpretations include batching (the radar device is not keeping up with an accelerating patrol vehicle) and shadowing (the radar device chooses a difference frequency between itself and the vehicle in its own lane). These effects are relatively common. Typically, the officer using the radar device has been trained to understand these limitations and other operating anomalies of radar devices. He or she will monitor the patrol speed reading determined by the radar device to determine whether the device is functioning properly. Some prior art radar devices have improved on the patrol speed acquisition problem by analyzing or monitoring certain Doppler waveform traits or signatures, such as in U.S. Pat. No. 5,528,246 to Henderson et al. However, these methods are not perfect and patrol speed misidentification remains a problem. Other radar devices, such as those disclosed in U.S. Pat. No. 5,565,871 to Aker et al. have a patrol reject button to actuate when the radar device is displaying an incorrect patrol speed. The radar device will then search for a different patrol Doppler return elsewhere in the spectrum.  
         [0004]     Another method of correctly identifying the patrol speed has been to use the output of the speedometer transducer in the patrol vehicle. The speedometer transducer provides a signal with a frequency proportional to the speed of the vehicle. The radar device receives the speedometer transducer signal, converts it to a speed and then uses the determined speed as a seed to search over a window in the return spectrum for a Doppler waveform with the corresponding patrol speed. A disadvantage of using this method is that the frequency from the speedometer transducer varies with different vehicle manufacturers. As a result, some form of calibration must be performed before using the radar device to take into account the particular frequency of the transducer. This calibration problem is compounded if the radar device is switched to a different vehicle, since re-calibration must then be performed again. In addition to the required calibration, the wire or cable from the speedometer transducer must be located and attached to the radar device. Of course, the location of the speedometer transducer wire or cable varies depending upon the model of the vehicle, and a further step is added to what is likely to be a lengthy manual hookup process.  
         [0005]     U.S. Pat. No. 4,335,382 to Brown et al., U.S. Pat. No. 6,023,236 to Shelton and U.S. Pat. No. 6,501,418 to Aker are illustrative of speedometer to radar device interface arrangements. The U.S. Pat. No. 4,335,382 patent teaches using a reference signal from a tachometer device having a frequency proportional to the rotational speed of a vehicle wheel. Complicated electronics including phase locked loops, dividers, frequency to voltage converters, phase detectors and the like are used lock an oscillator to the tachometer signal and to generate the reference signal.  
         [0006]     U.S. Pat. No. 6,023,236 to Shelton teaches using the signal from an electronic speedometer as an input to the radar device. The radar device converts the pulses from the speedometer and calculates the speedometer speed.  
         [0007]     U.S. Pat. No. 6,501,418 to Aker is concerned with automatically determining whether there is a coupling between a vehicle speed sensor and the radar device. This apparatus determines a ratio between true ground speed and the frequency output of the speed sensor that is then used in subsequent determinations of vehicle speed.  
         [0008]     Virtually all vehicles manufactured since 1996 have on-board electronics that can provide information about the speed of the vehicle. Unfortunately, such on-board electronics are designed to, and communicate, on different standards. For example, most foreign vehicles and those of the Daimler-Chrysler Corporation have on-board electronics that are designed in accordance with the ISO 9141 signaling protocol. On the other hand, vehicles manufactured by the General Motors Corporation have on-board electronics that communicate in accordance with a variable pulse-width (VPW) technique, and vehicles manufactured by the Ford Motor Company communicate in accordance with a pulse-width modulation (PWM) technique. These different signaling techniques are generally incompatible with each other because of the utilization of different bus arrangements, baud rates, and the like.  
         [0009]     In recent years, cameras and video systems are installed in police vehicles with increasing frequency. These video surveillance systems may be either of the analog type which uses a video tape, or of the digital type which stores the images in digital form in a digital storage medium. These video systems may be of assistance for evidentiary purposes in surveillance situations. Video images of an arrest may also help refute charges, such as police brutality, unreasonable searches and other issues. Such video images may also provide evidence in support of any charges that may be brought, the identity of the vehicle and so forth. Typically, it is desired to have a camera with a wide angle or field of view to capture as much information as possible. However, when a patrol vehicle is in motion, the peripheral information is frequently blurred by the speed of the vehicle and is generally unusable.  
         [0010]     There is therefore a need for apparatus that is capable of universally interfacing with the signaling protocols of on-board electronics in all types of vehicles to provide reliable and accurate patrol vehicle speed information to the radar device.  
         [0011]     Another need exists to provide an interface between the on-board electronics of the patrol vehicle that will eliminate the need to calibrate the on-board electronics to the radar device.  
         [0012]     Yet another need exists to provide an interface between the on-board electronics and the radar device that will permit the radar device to be relocated to a different patrol vehicle without requiring recalibration.  
         [0013]     A further need exists that provides for easy and quick installation of such an interface with the existing on-board electronics of the patrol vehicle.  
         [0014]     There is also a need for related methods of interfacing with the signaling protocols of all types of vehicles to provide reliable and accurate patrol speed information to the radar device.  
         [0015]     A need further exists for such apparatus that can automatically determine which on-board electronic signaling protocol of any vehicle and that can configure itself for operation with the signaling protocol of the vehicle.  
         [0016]     Another need exists for apparatus that adjusts the lens of a surveillance camera of a video surveillance system in accordance with the speed of the patrol vehicle to reduce extraneous peripheral information in the field of view at higher speeds.  
         [0017]     It is therefore a general object of the present invention to provide apparatus, such as a module, that is capable of universally interfacing with the signaling protocols of the electronics in all types of vehicles to provide reliable and accurate patrol vehicle speed information to the radar device.  
         [0018]     It is another object of the present invention to provide related methods of interfacing with the signaling protocols of the on-board electronics in all types of vehicles to provide reliable and accurate patrol speed information to the radar device.  
         [0019]     A further object of the present invention is to provide apparatus that can automatically determine which on-board electronic signaling protocol is present and that can configure itself for operation with the identified signaling protocol.  
         [0020]     Yet another object of the present invention is to provide apparatus that adjusts the lens of a surveillance camera of a video surveillance system in accordance with the speed of the patrol vehicle to reduce extraneous peripheral information in the field of view at higher vehicle speeds.  
         [0021]     A still further object of the present invention is to display and/or record the speed information that is determined by the apparatus with the images taken by the video surveillance system.  
       SUMMARY OF THE INVENTION  
       [0022]     The present invention is directed to apparatus for interfacing with the On-Board Diagnostic (OBD) computer (also referred to herein as the on-board electronics) in a vehicle with a radar device and/or a video surveillance system. A plurality of data busses are provided for communicating between the on-board electronics and the radar device and/or video surveillance system. These data busses are typically configured for different signaling protocols, such as variable pulse width (VPW), pulse width modulation (PWM) and ISO 9141 that are used by the various forms of the on-board electronics. One or more data processors determine the mode of signaling of the on-board electronics, such as by sequentially activating each of the plurality of data busses, and then select the data bus that is compatible with the on-board electronics. The data processor then communicates with the on-board electronics to receive data, which may be vehicle speed information, or the like, and then translate the received data into a form compatible with the radar device and/or the video surveillance system. The radar device will use the vehicle speed information when a patrol vehicle is in motion to calculate the speed of a target vehicle in a known manner.  
         [0023]     The camera may be a video camera for taking images, and it may part of a video surveillance system that also stores the images, either in analog or digital form. A second camera interface module may have a second data processor for receiving the translated data from the data processor and for communicating the translated data in a form for displaying the translated data with the images taken by the camera. Preferably, the camera has an adjustable field of view that can be adjusted in a plurality of steps from a wide angle of view to a narrow angle field of view depending upon the speed of the vehicle or a range of speeds of the vehicle. For example, the camera may be adjusted to a wide angle of view for a stationary vehicle and for slow speeds and may be adjusted to a narrower field of view for intermediate speeds and to a still narrower field of view for higher vehicle speeds. A narrower field of view at higher speeds eliminates peripheral information which is likely to be blurred by the speed of the vehicle.  
         [0024]     The present invention also includes methods of interfacing between the on-board electronics in a vehicle and a radar device and/or a video surveillance system where the interface apparatus has a plurality of busses configured to operate with different signaling protocols. One of the methods includes the steps of activating at least one of the plurality of data busses to determine the signaling protocol of the on-board electronics, selecting the data bus from the plurality of data busses that is compatible with the signaling protocol of the on-board electronics, translating the received data into a form compatible with the radar device and/or the video surveillance system, and communicating the translated data to the radar device and/or the video surveillance system. The step of selecting a data bus may include the steps of selecting a variable pulse width bus, a pulse width modulation bus or an ISO 9141 bus. The step of communicating translated data may include the step of communicating speed information.  
         [0025]     The methods employed with the video surveillance system may further include displaying the translated data with an image taken by the camera, such as by known metadata techniques. Another step may be to use the translated data to control the field of view of the camera, and to narrow the field of view of the camera at higher vehicle speeds. Controlling the field of view of the camera may be done in a plurality of steps, with each field of view step associated with a range of vehicle speeds. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0026]     The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. The invention, together with the further objects and advantages thereof, may best be understood by reference to the following description taken in conjunction with the accompanying drawings, in the several figures in which like reference numerals identify like elements, and in which:  
         [0027]      FIG. 1  is a block diagram of the radar and video interface module of the present invention illustrating the interfacing of the module between a radar device and a video surveillance system and the on-board electronics in a vehicle;  
         [0028]      FIG. 2  is a block diagram of the of the interface module of  FIG. 1  in greater detail;  
         [0029]      FIG. 3  is a block diagram of another module for interfacing between the interface module of  FIGS. 1 and 2  and a surveillance camera;  
         [0030]      FIG. 4  is a schematic diagram of the interface module shown in  FIGS. 1 and 2 ;  
         [0031]      FIGS. 5A-5D  are flowcharts of software used by the interface module of  FIGS. 1 and 2  to determine the mode of operation of the module to coordinate communication in the proper protocol with the on-board electronics installed in a vehicle;  
         [0032]      FIG. 6  is a flowchart of the software used by the interface module of  FIGS. 1 and 2  for the serial port interrupt of an internal microcontroller;  
         [0033]      FIG. 7  is a flowchart of the software used to determine whether the radar device of  FIG. 1  operates in the automatic interfacing mode or in the manual patrol mode;  
         [0034]      FIGS. 8A and 8B  are flowcharts of software used by the radar device of  FIG. 1  when in the automatic interfacing mode;  
         [0035]      FIG. 9  is a flowchart of software used by the radar device of  FIG. 1  to determine whether the radar device is in the automatic interfacing mode or in the manual mode; and  
         [0036]      FIG. 10  is a flowchart of software used to adjust the field of view of a camera in the video surveillance system of  FIG. 1  in accordance with the speed of the patrol vehicle. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0037]     Referring to the Figures, and particularly to  FIG. 1 , a radar and video interfacing module, generally designated  20 , interfaces between an On-Board Diagnostic (OBD) computer or electronics  21  in a motor vehicle and a radar device  24  and/or a video surveillance system  26  via an OBD interface connector  22 , and provides communication between the OBD electronics  21  and the radar device  24  and/or the video surveillance system  26 . Such OBD computers have been installed in all vehicles since 1996. The radar device  24  thus receives vehicle speed information from the OBD electronics  21  independent of the make or model of the vehicle. The communication path between the OBD electronics  21  and the radar device  24  is provided by electronic circuitry  70 , which is described in detail below with reference to  FIG. 4 . This circuitry interrogates a plurality of different busses to select and use a bus that is compatible with signaling format the OBD electronics. The radar device  24  then automatically receives correct vehicle speed data from the OBD electronics  21 . A significant advantage of the present invention is that there is no need to calibrate the radar device to the OBD interface for the particular signaling format of the OBD electronics since module  20  automatically identifies and provides a compatible signaling interface and correctly determines the vehicle speed from any OBD electronics signaling format. Another important advantage of the present invention is that the radar device  24  and module  20  may be relocated to any other vehicle without requiring recalibration since module  20  will quickly and automatically adapt to any new signaling format. A further advantage of the present invention is that module  20  is provided with a standard OBD electronics connector  22  that will plug into the OBD electronics  21 . There is therefore no need to search for, and connect to, a speedometer transducer wire or connector.  
         [0038]     Of course, module  20  may be in the form of other types of housings, circuit boards or the like. For example, module  20  could be a unitary part of the radar device  24 . That is, the electronic functions of module  20  could be designed and integrated into radar device  24 , thereby eliminating the need for a separate module. Module  20  provides communication between the OBD electronics  21  and the radar device  24  and/or the camera  26 . For example, module  20  may provide the speed of a patrol vehicle to the radar device  24  so that the radar device can accurately take into account the speed of the patrol vehicle in determining the speed of a target vehicle. Similarly, the surveillance camera in the video surveillance system can have its field of view adjusted depending upon the speed of the patrol vehicle, such as by using a wider field of view for slower patrol vehicle speeds and using a narrower field of view for faster patrol vehicle speeds.  
         [0039]     While OBD electronics have been installed in all vehicles made since 1996, different versions of the OBD electronics exist. General Motors Corporation has its proprietary OBD design for its vehicles. Ford Motor Corporation similarly has its proprietary design. Daimler-Chrysler Corporation and most of the other vehicle manufacturers design their OBD electronics to an ISO 9141 industry standard. Thus, module  20  preferably accommodates all three OBD electronic designs for adaptability to all vehicles.  
         [0040]      FIG. 2  illustrates the radar and video interfacing module  20  in greater detail. One or more microcontrollers  30  control and coordinate communication between the OBD electronics  21  and the radar device  24  and/or the camera  26 . The microcontrollers may be any type of suitable data processors, including microprocessors or the like. In this respect, a variable pulse-width (VPW) transceiver circuit  32  bi-directionally communicates with the microcontrollers  30  and with the OBD electronics  21  via a line  32  for the General Motors signaling protocol. A pulse-width modulation (PWM) transceiver circuit  36  similarly communicates with microcontrollers  30  and with the OBD electronics via lines  34  and  38  for the Ford signaling protocol. Another PWM transceiver  40  communicates with microcontrollers  30  and with the OBD electronics via lines  42  and  44  for the ISO 9141 signaling protocol. Interface module  20  may also or optionally be designed to provide signaling compatibility with the CAN 2.0B bus standard referenced in the SAE J-2264 and ISO-118980 standards. Microcontrollers  30  will determine which of the transceivers  32 ,  36  or  40  is appropriate for the particular signaling format, i.e., which signaling protocol is applicable in each installation.  
         [0041]     Microcontrollers  30  will, in turn, provide information to camera  26  via one or more lines  46 . An RS232 driver  48  may receive information from microcontrollers  30 , and in turn, provide such information to a radar device  24 , such as a hand-held radar gun.  
         [0042]     A video module  52  provides further interfacing with camera  26  and is shown in  FIG. 3 . As with module  20 , module  52  may in the form of other types of housings, circuit boards or the like. Of course, it may also be desirable to provide modules  20  and  54  as a unitary module instead of separate modules. In general, video module  52  may display additional data with the images that the camera is taking, such as the time of day, the date, the speed of the patrol vehicle, the identification of the patrol vehicle, and the like. Data from module  20  in  FIGS. 1 and 2  is received from one or more microcontrollers  30  on line  46  to one or more microcontrollers  54 . Line  56  from the microcontrollers  54  provides serial data to the camera and line  57  receives serial data from the camera. A line  59  from the microcontrollers provides data to a video circuit  58 . A line  61  provides video with data from video circuit  58  to the camera, and line  60  receives video from the camera to the video circuit.  
         [0043]     The schematic diagram for the electronic circuitry, generally designated  70 , for the interface module  20  is shown in  FIG. 4 . Connector  22  may be of an industry standard type, such as J-1962, to interface with the OBD-II electronics in the motor vehicle, and it consists of 9 pins in this example. Pins  1  and  2  of connector  22  are grounded, pin  9  supplies operating power and pins  4 ,  6 ,  7  and  8  are connected to the various busses that comprise the OBD-II interface. The OBD-II interface has provisions for interfacing and communicating with the three different signaling protocols of the automotive manufacturers, as explained above.  
         [0044]     The transceiver portion of the circuitry  70  for interfacing with the General Motors (GM) design and specification is shown in the upper right portion of the schematic diagram of  FIG. 4 . A pair of comparators  71 - 72  and a transistor  73  are the active elements of a variable pulse width (VPW) transceiver that communicates over a bi-directional bus  75  to pin  7  of connector  22 , and hence, to the GM OBD-II electronics. Data is transmitted and received bi-directionally on bus  75  at about 10,400 baud. Comparators  71 - 72  are commercially available from a number of vendors; for example, from National Semiconductor of Santa Clara, Calif. under part number LM339N. Resistors  76  and  77  form a voltage scaling divider for the input of comparator  72 ; which has its inverting input terminal referenced to a voltage reference of about +2.5 volts. Resistor  78  is used as a pull up for the output of the receiver comparator  72 , with the output of receiver comparator  72  routed to the VPW RX pin  7  of a microprocessor  80 .  
         [0045]     Comparator  71 , resistors  83  and  84  and transistor  73  form the transmitter of the GM transceiver section. Comparator  71  receives information from VPW TX pin  6  of microprocessor  80  at its non-inverting terminal. Its inverting terminal is referenced to a voltage reference of about +2.5 volts. A diode  86  provides protection from the bi-directional bus  75 . A Zener diode  85  acts as a voltage reference of approximately 9.1 volts for the collector of transistor  73 .  
         [0046]     The transceiver portion of the circuitry  70  for interfacing with the Ford Motor Corporation (Ford) design and specification is shown in the middle right portion of the schematic diagram of  FIG. 4 . Comparator  90  and a pair of transistors  91 - 92  are the active elements of a pulse width modulated (PWM) transceiver that communicates over positive and negative bi-directional busses  75  and  89 , respectively, to pins  7  and  6  of connector  22 , and hence, to the Ford OBD-II electronics. Data is transmitted and received bi-directionally on busses  75  and  89  at about 41,600 baud. A pair of resistors  94  and  95  form a voltage scaling network for the inverting input of comparator  90  and generate the proper output voltage levels for the bus signal BUS-41600 on bus  89 . A resistor  99  operates as a pull up for the output of comparator  90  and for the PWM RX pin  8  of microprocessor  80 . The output terminal of comparator  90  communicates the received data on busses  75  and  89  to the PMW RX pin  8  of microprocessor  80 .  
         [0047]     A negative PWM transmitter includes resistor  96  and transistor  92 . The base terminal of transistor  92  receives data from the PWM−TX pin  10  of microprocessor  80  to transmit data on the negative bus  89 . A positive PWM transmitter includes resistor  97  and transistor  91 , which receive data from the PWM+TX pin  9  of microprocessor  80 . A diode  98  protects transistor  91  from over-voltage conditions that may occur on the bus  75 .  
         [0048]     The transceiver portion of the circuitry  70  for interfacing with designs that are in accordance with the ISO 9141 specification, including with the Daimler-Chrysler Corporation and many foreign vehicle manufacturers, is shown in the lower right portion of the schematic diagram of  FIG. 4 . A comparator  101  and a transistor  102  are the active elements of the ISO 9141 transceiver that communicates over a bi-directional bus  100  at about 10,400 baud. Comparator  101  receives data and commands from the bus  100  at its non-inverting terminal. A pair of resistors  104  and  105  form a voltage scaling network for the input of the comparator  101 . A resistor  106  is a pull-up for the output of comparator  101  and the K LINE RX pin  13  of microprocessor  80 . Comparator  101  thus communicates received data on bus  100  to microprocessor  80 . Transistor  102  has its base terminal referenced to the K LINE TX pin  11  of microprocessor  80  and its collector terminal tied to bus  100 . Transistor  102  communicates data to be transmitted from microprocessor  80  onto bus  100  to pin  4  of connector  22 . Another transistor  108  has its base terminal referenced to the L LINE TX pin  12  of microprocessor  80  and has its collector terminal tied to the 5 BAUD bus  109 . Transistor  108  communicates data from microprocessor  80  onto the 5 BAUD bus  109  to pin  8  of connector  22 . Transistors  102  and  108  comprise output transistor drivers for communicating to the 10400 BAUD bi-directional bus  100  and to the 5 BAUD bus  109 , respectively.  
         [0049]     Microcontroller  80  is the main controller for the module  20 . Any of a variety of microcontrollers or microprocessors may be suitable for this application. For example, microcontroller  80  may be an 8-bit microcontroller that is commercially available from the Microchip Corporation of Chandler, Ariz. under part number PIC17F84. Microcontroller  80  can communicate with any of the three standard buses of the OBD-II interface. As discussed above, pins  6  and  7  communicate with the GM interface, pins  8 - 10  communicate with the Ford interface and finally pins  11 - 13  communicate with the ISO 9141 interface. A pair of capacitors  111  and  112  and a crystal  113  form an oscillator circuit for microcontroller  80  that may oscillate at, for example, at about 20 MHz. A resistor  114  and a capacitor  115  provide a reset signal during initial power on. A capacitor  116  provides power supply de-coupling.  
         [0050]     A second microcontroller  81  functions as an interface controller for module  20 . While microcontroller  81  could be selected from a variety of commercially available microcontrollers and microprocessors, it may be an 8-bit microcontroller commercially available under part number PIC16F628 from Microchip Corporation. Microcontroller  80  communicates serial speed information to and from microcontroller  81  on a pair of lines  117  and  118 . Microcontroller  81  translates the 19200 BAUD rate from microcontroller  80 , as on lines  117  and  118  to the lower 1200 BAUD rate required by the external radar device and camera,  24  and  26 , respectively. Resistors  126  and  127  in lines  117  and  118 , respectively, provide buffering between microcontrollers  80  and  81 . A pair of capacitors  120  and  121  and a crystal  122  form a oscillator circuit for microcontroller  122 , which may also oscillate at about 20 MHz. A resistor  123  and a capacitor  124  provide a reset signal on initial power on. A capacitor  125  provides power supply de-coupling.  
         [0051]     A programming port  128  allows in-circuit re-programmability of microcontrollers  80  and  81 . An RS232 interface IC  130  provides RS232 interfacing between the radar device  24 , which is connected to a port  140 , and microcontroller  81 . For example, the RS232 IC  130  is commercially available from Maxim Corporation of Sunnyvale, Calif. under part number MAX232. RS232 IC  130  receives data from microcontroller  81  at T1 IN pin  11 . Capacitors  131 - 135  are used by the RS232 IC  130  to provide positive and negative voltages required for the RS232 interface. IC  130  also supplies data to the camera  26  at a port  141 .  
         [0052]     Regulated power is supplied to the electronic circuitry  70  by an IC  143 , such as that commercially available from the National Semiconductor Company of Santa Clara, Calif. under part number LM349S-5.0. A regulated +5 volts is provided at terminal  144 . A plurality of capacitors  145 - 148  provides power supply decoupling. A pair of resistors  149  and  150  and a capacitor  151  provide a 2.5 volt reference for the inverting terminals of comparators  71 ,  72  and  101 .  
         [0053]     The interfacing of the electronic circuitry  70  is as follows. Connector  141  communicates 1200 BAUD rate TTL voltage levels from microcontroller  81  to the external camera  26 . Connector  140  is a pass through connector that allows a radar device  24  to transmit speed information to a video recorder unit (not shown). Connector  142  is preferably of the DB-9 type to interfaces with the radar device  24 . The radar device  24  receives data from the RS232 IC  130  at pin  3  of connector  142 . Data transmitted from the radar device  24  is routed from pin  2  of connector  142  to the pass through connector  140 .  
         [0054]     It will be appreciated by those skilled in the art that various alternatives, variations and changes may be made to the electronic circuitry  70 . Instead of designing the circuitry  70  with discrete components, other parts are also commercially available for designing and implementing OBD-II interfaces. For example, Motorola Inc. of Schaumburg, Ill. manufactures several OBD-II interface chips, such as the MC33290 serial link bus interface, which communicates directly between a microcontroller and the ISO 9141 bus.  
         [0055]     The module  20  determines the mode of operation of the on-board electronics by sequentially activating the various busses to establish communication with the on-board electronics in the appropriate signaling protocol, as seen in the software flowcharts of  FIGS. 5A-5D . The main program starts at block  155  of  FIG. 5A  by instructing microcontroller  80  to initialize the VPW bus  75 . The routine waits for 5 seconds at decision block  156  for a valid response. If a response is received, the routine branches over to the VPW loop at block  157  and to the VPW loop of block  158  in  FIG. 5B . If no response is received, the routine sends out a error string at block  159  and branches down to test the PWM bus  75  and  89 . The PWM bus is initialized at block  160  and the routine waits 5 seconds at block  161  for a response. If a response is received, the routine branches over to the PWM loop of block  162  and to the PWM loop routine beginning at block  163  of  FIG. 5C . If no response is received, the routine sends out an error string at block  164  and branches down to test the ISO bus. The ISO bus  100  and  109  is initialized at block  165  and the routine waits 5 seconds for a response at block  166 . If a response is received, the routine branches over to the ISO loop at block  167  and to the ISO routine at block  168  in  FIG. 5C . If no response is received, the routine sends out an error string at block  169  and branches back to the program start.  
         [0056]     The VPW routine begins at block  158  of  FIG. 5B . The routine requests speed data from VPW bus  75  at block  171 . If no response is received within 100 milliseconds at block  172 , the routine increments an error count at block  173 . If the error count reaches 20 at block  174 , the routine will go to the program start at block  175 , which causes a return to the program start block  154  in  FIG. 5A . If the error count is less than 20, the routine will again request speed data from the VPW bus at block  171 . If a speed is received at block  172 , its CRC byte is checked for validity at block  176 . If the speed is valid, it is sent out on the serial port at block  177 , the error count is reset at block  178  and the routine jumps back to request a additional speed from the bus at block  171 . If the speed of the CRC value is incorrect, the error count is incremented at block  173  and checked at block  174  before jumping back to request a new speed at block  171 .  
         [0057]     The PMW routine begins at block  163  of  FIG. 5C . The routine requests speed data from PMW bus at block  178 . If no response is received within 100 milliseconds at block  179 , the routine increments an error count at block  180 . If the error count reaches 20 at block  181 , the routine will go to the program start at block  182  and back to program start block  154  of  FIG. 5A . If the error count is less than 20, the routine will again request speed data from the PMW bus at block  179 . If a speed is received at block  179 , its CRC byte is checked for validity at block  183 . If the speed is valid, it is sent out on the serial port at block  184 , the error count is reset at block  185  and the routine jumps back to request a additional speed from the bus at block  178 . If the speed associated with the CRC value is incorrect at block  183 , the error count is incremented at block  180  and checked at block  181  before jumping back to request a new speed at block  178 .  
         [0058]     The ISO routine begins at block  168  of  FIG. 5D . The routine requests speed data from ISO bus at block  185 . If no response is received within 100 milliseconds at block  186 , the routine increments a error count at block  187 . If the error count reaches 20 at block  188 , the routine will go to the program start at block  189 , and then back to program start block  154  in  FIG. 5A . If the error count is less than 20 at block  188 , the routine will again request speed data from the ISO bus at block  186 . If a speed is received at block  186 , its CRC byte is checked for validity at block  190 . If the speed is valid, it is sent out on the serial port at block  191 , the error count is reset at block  192  and the routine jumps back to request a additional speed from the bus at block  185 . If the speed associated with CRC value is incorrect at block  190 , the error count is incremented at block  187  and checked at block  188  before jumping back to request a new speed at block  185 .  
         [0059]      FIG. 6  is a flowchart of the programming steps for the serial port interrupt beginning at block  200 . When the radar device  24  receives a serial 8-bit word from the interface module, the execution of software in the radar device jumps to this block. The string received (composed of three words) is checked to verify it came from the interface module at block  201 . The radar device will process the received string differently, as at block  202 , if it is not from the interface module. If an automatic interface string was received, it is checked for an error code at block  203 . An error code will force the VIP (automatic interface mode) variables VIP_MODE, VIP_SPEED, VIP_BIN and VIP_TIMEOUT to be set to zero for operation of the interface module in the manual mode at block  204 . If the VIP string was received correctly, the following variables are set for the automatic mode of operation: VIP_MODE=1, VIP_SPEED is updated with the value located in the string and VIP_TIMEOUT is set to a value representing a two second timeout at block  204 . VIP_TIMEOUT is used to detect if the interface module was removed or an interface error became present. Finally at block  205 , VIP_BIN is calculated by converting VIP_SPEED into an equivalent fast Fourier transform (FFT) bin number. VIP_BIN is used in the automatic patrol interfacing routine to determine a valid patrol FFT bin. The serial string received from the interface module contains a three word 8 bit string consisting of an ASCII O, the binary speed in KPH and a carriage return &lt;CR&gt; or decimal  13 . If an error is received, the string will be ASCII E, binary speed of zero, and a &lt;CR&gt;. Baud rates are 1200, 8 data bits and no parity. It will be appreciated that many different serial formats could be used.  
         [0060]      FIG. 7  is a flowchart of the VIP_TIMEOUT process. This routine is called from the main program at block  210  and is used to decrement the VIP_TIMEOUT variable at block  211 . If the VIP_TIMEOUT variable has expired, the VIP variables are reset at block  213  and the radar device defaults to the manual patrol interfacing mode. VIP_MODE, VIP_SPEED and VIP_BIN will all be set to zero.  
         [0061]      FIGS. 8A and 8B  are flowcharts for the automatic patrol interfacing routine. The routine is called from the main program at block  215 . First, it is determined if the radar is in VIP_MODE at block  216 . If VIP_MODE is set to zero, the processing jumps to manual patrol processing at block  217 . In the manual processing mode, the radar device processes the patrol speed Doppler return in a conventional manner. The VIP_MODE was set in  FIG. 6  if a valid VIP string was received. If VIP_MODE is set to a one, the radar device will drop down into patrol automatic interfacing mode. The routine next initializes the distance in bins from which to process the VIP_BIN value. In this example, 6 bins are used to define the maximum distance from the VIP_BIN value at block  218 . PBIN_MAX is initialized to zero and is used as a flag to determine if a patrol speed was found in the search. A loop is next executed at block  219  to search for the closest target to the VIP_BIN value. The loop is executed over an array of sorted top strong targets at block  220 , searching from the strongest target in the return (bin value=0) to the Nth strong target (bin_value-1). The array of targets is calculated in an earlier step main program function by finding the strongest target in the return and placing its reference value in bin location 0, the second strongest target in the return in bin location 1, the third strongest in bin location 2 and so on. N equals 25 in this case but may vary and is not a limitation. The routine picks out the next bin value from the sorted array at block  220  and compares its distance to VIP_BIN value. If the magnitude of the distance at block  221  is less than the required amount defined earlier by DISTANCE then this FFT bin value is used as the patrol bin. If the patrol bin is found, PBIN_MAX is initialized to the FFT bin location. The loop continues to execute while checking on PBIN_MAX at block  222  to determine if it has been updated. If PBIN_MAX equals a non-zero value it is not updated with any new values at block  223 . The loop will exit when the loop variable has decremented to zero at block  224 , and goes to block  225  of  FIG. 8B . The routine next retrieves the target information located at PBIN_MAX which provides frequency information and valid properties about the patrol signal at block  225 . The patrol signal is next checked to determine if it is valid at block  226 . The patrol signal will be valid if its frequency has been within a certain threshold over a period of time. If PBIN is not valid, the patrol speed value is set to zero at block  227  and procedure returns. If PBIN is valid it is converted into a speed at block  228  and the procedure returns. The radar will display the valid patrol speed in the patrol window.  
         [0062]      FIG. 9  is a flowchart for the automatic/manual switchover capability of the radar device beginning at block  230 . For ease of operation, it is desirable to have the radar device automatically switch over to stationary mode if the patrol vehicle is stopped. Likewise, it is also desirable to have the radar device to switch back to moving mode once the patrol vehicle is moving again. It is also important from the operator&#39;s point of view that the mode switchover be selectable from either automatic or manual settings. The radar device preferably contains a software menu that the operator can use to select between manual and automatic mode switchover. VIP_CHOICE at block  231  is the variable used to hold the state of the manual/automatic switchover and its status is saved in non-volatile memory on power down and recalled on power up. First, the VIP_CHOICE variable is checked to determine if the radar is in automatic or manual mode switchover. The routine exits if VIP_CHOICE is equal to a 1 meaning that the radar is in manual mode. In manual switchover mode, the radar will display a zero in the patrol window when the radar device has come to a stop and will not display any target speeds nor will the device switch over automatically to stationary mode.  
         [0063]     If VIP_CHOICE is zero (automatic mode), the routine drops down to block  232  and checks for VIP_MODE. If VP_MODE=0 then the routine exits because no VIP module is connected. If VIP_MODE=1, the routine drops down to block  233  and checks the VIP_SPEED value. If VIP_SPEED=0 the routine will check to determine if the radar is in stationary mode at block  234 . If VIP_SPEED=0 and the radar is in stationary mode, the radar device is set to the stationary mode at block  235  and the routine exits because the radar device is already in the correct mode. However, if VIP_SPEED is non-zero at block  233 , the routine checks if the radar is in moving mode at block  236 . If the radar is in moving mode, the routine exits. If VIP_SPEED is non-zero and the radar device is in stationary mode, the routine places the radar device into moving mode at block  237  based upon the previous moving mode of the radar device and exits.  
         [0064]      FIG. 10  is a flowchart for providing information to a video surveillance system  26  in  FIG. 1 , which may include a camera, a digital storage medium, a video recorder, and/or the like. In addition to providing speed information to a radar device, the interface module can also provide information to the camera  26  located in a video surveillance system, and which forms part of a video surveillance system. For example, the video surveillance system  26  may be an analog system that records onto a video tape. For an analog system, all of the information is stored as part of the video signal, including any speed information or information of the like furnished by interface module  20 , is stored as part of the video signal on the tape. However, preferably, the video surveillance system is a digital video system that digitizes the video information. Additional information or metadata, which may include time, date, vehicle identification, frame number, vehicle speed and the like, is associated with the digitized data on a frame by frame basis, in a manner known to the art. The playback software then combines the digitized data and the metadata to recreate the images. Since the metadata is in digital form, it may not be desired to display all of the data on playback. The metadata may be used in other ways such as tags for searching. For example, the vehicle speed data from the interface module  20  could be used to adjust the field of view of a camera in the video surveillance system, and the speed information could be displayed on the images created by the camera, either instantaneously or on playback, or not, as desired.  
         [0065]     It is frequently desirable to adjust the zoom level of the camera depending on the present speed of the patrol vehicle. It is known that the information in the peripheral view of the camera typically becomes more and more extraneous as the speed of the patrol vehicle increases. For example, as the speed of the patrol vehicle increases, peripheral roadside objects may appear blurred. In addition, target vehicles of the radar device are usually spread further apart at highway speeds. This causes a wider angle image or a wider field of view, which is suitable for slower traffic and/or slower patrol speeds, to have less detail and less sharpness for faster traffic and/or for faster patrol speeds. Thus, it can be appreciated that adjustment of the zoom feature of the camera based upon the speed of the patrol vehicle is desirable. In particular, it is desirable to have a higher zoom factor at higher patrol vehicle velocities.  
         [0066]     An exemplary flowchart for adjusting the zoom of the lens of the camera is set forth in  FIG. 10 . Software located at the camera  26  will receive data from the interface module  20  and use the speed information to control the field of view of the camera. After starting at block  240 , the program waits for incoming data from the VIP port at block  241 . The routine checks if the first byte received in the string is a “O” at block  242 . If not, the routine returns back to checking the VIP port. If a “O” was received, the binary speed is converted to from kilometers per hour (KPH) to miles per hour (MPH) at block  243 . The next decision block  244 , checks the patrol speed to determine if it is less than about 15 MPH. If the patrol speed is less than 15 MPH, the routine causes adjustment of the camera lens to about full wide angle at block  245 . The routine next sends the actual present speed of the patrol vehicle for video display of the speed with the image produced by the camera at block  246 .  
         [0067]     If the patrol speed is greater than about 15 MPH and less than about 35 MPH at block  247 , the routine adjusts the camera lens to about 1.5× at block  248  and, as before, sends the present speed of the patrol vehicle to the camera for display on the camera&#39;s image. If the patrol speed is greater than about 35 MPH and less than about 55 MPH at block  249 , the routine adjusts the camera lens to about 2.0× at block  250  and sends the present patrol vehicle speed to the camera for display on the camera&#39;s image at block  246 . If the patrol speed is greater than about 55 MPH at block  251 , the routine will adjusts the camera lens to about 2.5× and, as before, the speed is sent to the camera for video display. It will be appreciated that the speed ranges and camera adjustments in the foregoing example are set forth as an example of practicing the present invention and that other speed ranges and camera lens settings may be also be suitable for practicing the present invention.  
         [0068]     It will be understood that the embodiments of the present invention that have been described are illustrative of some of the applications of the principles of the present invention. Various changes and modifications may be made by those skilled in the art without departing from the true spirit and scope of the invention.