Patent Publication Number: US-2005134710-A1

Title: Imaging systems for use with patrol cars and patrol cars having such imaging systems

Description:
This application claims priority to Japanese patent application serial numbers 2003-421014, 2004-44156, and 2004-218764, the contents of which are incorporated herein by reference.  
     BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to imaging systems for use with patrol cars and also relates to patrol cars having such imaging systems.  
      2. Description of the Related Art  
      Japanese Laid-Open Patent Publication No. 11-312300 teaches an imaging system adapted to be mounted to an automobile. The imaging system includes a camera mounted on the automobile so that the information required for safe traveling can be collected in response to the traveling speed of the automobile. For example, such information may include the monitoring of the preceding automobile or the succeeding automobile and information with regard to the location of the white line on the road.  
      In recent years, there has been an increasing demand for patrol cars to have cameras mounted thereon in order to automatically record various pieces of information with regard to the locations traveled to by the patrol cars.  
      However, the camera of the above Japanese publication is intended to support the safe traveling of an ordinary automobile. Therefore, the camera is used for collecting information that may support the safe traveling of the automobile to which the camera is mounted. The collected information is necessary for supporting the safe traveling of the automobile at that immediate time, but the collected information is not recorded and reproducible later for the purposes of the safe traveling. In addition, although the camera of the above Japanese publication picks up images of the preceding and succeeding automobile and the location of the white line placed upon the road, the camera is not adapted to take up or record image information with regard to the places traveled to by the automobile.  
      In addition, in the case of a patrol car, such as police cars for example, a number of devices are mounted to the patrol car in order to provide various specialized police services. For example, such devices may include a hand-operated spotlight for illuminating areas in desired directions, a microphone, a loudspeaker for announcements to the outside of the police car, a siren, a radar speed measurement device, a police radio, and an emergency light.  
      Recently, there has been a proposal in some cases to mount a camera and a hard disc drive (HDD) to a police car. A controller having input buttons may also be mounted to the police car for operating the devices. The controller may preferably be disposed at a position where an operator can easily access the input buttons from either a driver&#39;s seat or a passenger seat. In general however, the controller for operating the devices used for the various police services has a relatively large size. Therefore, there has been a problem in that it is difficult to ensure enough space for placing the controller.  
      For example, Japanese Laid-Open Patent Publication No. 2002-357557 teaches an image pick-up device that is adapted to be mounted to an emergency vehicle, such as a police car for example. In this publication, a camera, a data-recording device, and a GPS (Global Positioning System) are mounted to the emergency vehicle. However, the overall system typically has a relatively large size and increased introduction costs with this arrangement.  
      As taught with this system, video information picked up during the traveling of the vehicle is recorded on a recording medium, such as a video tape and an HDD of a data recording device, together with information regarding the position of the vehicle at the time of the recording of the information. The devices mounted on the vehicle can communicate with an outside administration center via a communication network. For this purpose, communication sections  40  and  41  are respectively provided on the vehicle and at the administration center. The administration center also has a data-recording device. With this particular arrangement, the video data captured by the camera is recorded on the data-recording device of the vehicle. In addition, the video data is transmitted to the data-recording device of the administration center via the communication network. At the administration center, the video data is recorded on the data-recording device.  
     SUMMARY OF THE INVENTION  
      It is accordingly an object of the present invention to teach improved image recording devices for use with patrol cars and patrol cars having such improved imaging systems.  
      According to one aspect of the present teachings, imaging systems are taught for mounting on patrol cars, such as police cars. The imaging systems include at least one image pick-up device having an optical axis. A direction-changing device serves to change the angle of the optical axis of the image pick-up device with respect to at least one of either a horizontal direction or a vertical direction. A zooming device serves to change a focal distance of the image pick-up device. At least one sensor detects a condition related to the vehicle and outputs a corresponding detection signal. An image memory device stores image information picked by the image pick-up device. A controller serves to select one of image pick-up modes in response to the detection signal and control at least one of either the direction-changing device or the zooming device based upon the detection signal, in order to capture images via the image pick-up device.  
      Therefore, the imaging systems can operate in various image-pick up modes in response to the detected condition(s) of the sensor(s). As a result, the operability of the imaging systems may be improved.  
      In one embodiment, the sensor is a speed sensor for detecting the traveling speed of the vehicle. The image-pick up modes includes a first mode that is selected when the controller determines a vehicle stop condition based upon the sensor detection signal. In the first mode, when the patrol car, traveling to a target place, has stopped at the target place, at an intersection, or a railroad crossing, the image around the stopped vehicle can be suitably captured and stored.  
      In addition to the speed sensor, the imaging systems may further include a positional information acquisition device, such as a GPS, operable to detect the current location of the vehicle and output a positional signal. The image-pick up modes includes a second mode that is selected when the controller determines a vehicle stop condition based upon the detection signal of the sensor and when the controller determines that the current vehicle position is within a predetermined district. If the target place is set to a predetermined district, the imaging systems may not operate in the first mode when the patrol car has temporarily stopped prior to reaching the target place. In addition, if the urban district is set to be the predetermined district, the imaging systems may not operate in the first mode to capture images while the patrol car is located in a suburban district. Suburban district images may be considered not as important during a typical patrol  
      In another embodiment, the sensor is an emergency sensor that detects the emergent response condition of the vehicle. The image-pick up modes includes a third mode that is selected when the controller determines an emergency response condition based upon a detection signal of the emergency sensor. In the third mode, the optical axis of the image pick-up device is directed in the traveling direction of the vehicle. Therefore, it is possible to suitably capture and record images even during an emergency response condition.  
      In a further embodiment, a first image pick-up device and a second image pick-up device are respectively operable to capture images inside and outside of the vehicle. The sensor is a passenger sensor that detects a passenger seated on the rear seat of the vehicle. The image-pick up modes includes a fourth mode that is selected when the controller determines the existence of a passenger on the rear seat based upon the passenger sensor detection signal. In the fourth mode, the images picked up by the second image pick-up device are stored in a memory unit. Consequently, the images of a passenger can be suitably captured and recorded.  
      In a still further embodiment, the sensor is a communication sensor that detects police radio communication. The image-pick up modes includes a fifth mode that is selected when the controller determines the establishment of the police radio communication based upon the detection signal of the communication sensor. As a result, the images of a policeman who is using a police radio transmitter can be automatically captured and recorded.  
      In a still further embodiment, the sensor includes a speed sensor for detecting the traveling speed of the vehicle and a steering angle sensor for detecting the steering angle of the vehicle. The controller is operable so as to estimate a direction of the line of sight of the driver of the vehicle based upon the signals from the speed sensor and the steering sensor. The image-pick up modes includes a sixth mode that is selected to control based upon the estimated direction of the sight line. Therefore, the images in the estimated direction of the sight line of the driver can be suitably and automatically captured and recorded.  
      In a still further embodiment, the sensor is a signal sensor for detecting a communication signal outputted from a portable communication device. The controller determines the direction of the portable communication device with respect to the vehicle based upon the detected communication signal. The image pick-up modes include a seventh mode that is selected to control based upon the direction of the portable communication device. Therefore, the images of a person or an object carrying the portable communication device can be automatically captured and recorded.  
      For example, the direction sensor may be a receiver for receiving the communication signal from the portable communication device.  
      In a still further embodiment, the sensor is a capacity sensor for detecting the remaining capacity of the power source of the imaging system. The image pick-up modes comprise an eighth mode that is selected when the remaining capacity of the power source is less than a predetermined value. For example, the operation of at least one of either the direction change device or the zooming device may be stopped in the eighth mode in order to save power.  
      In another aspect of the present teachings, patrol cars having imaging systems are taught. The imaging systems may include at least one image pick-up device, a memory device, and a controller The controller may execute instructions to record the image information captured by the image pick-up device in the memory device, and may execute instructions to control devices relating to patrol situations. Therefore, a driver or a passenger of the patrol car can operate the controller of the imaging system in order to function according to various patrol situations. By positioning the controller at a position that is easily accessible by either the driver or the passenger, it is not necessary for the driver or the passenger to lean or substantially reposition himself or herself toward the controller in order to control the devices relating to the patrol situations.  
      For example, the controller may have a control unit sized so as to be mounted into the existing storage space provided in a patrol car in order to accommodate the main body of commercial audio equipment.  
      In a still further aspect of the present teachings, the controller additionally includes a relay device connected between the image pick-up device and the control unit. The relay device may be disposed outside of the storage space and may be connected to at least one terminal device.  
      In a further aspect of the present teachings, patrol cars are taught that include imaging systems that include a positional information acquisition device, a transmitter, and an input device, in addition to at least one image pick-up device, a memory device, and a controller. The memory device serves to store image information captured by the image pick-up device. The positional information acquisition device functions so as to obtain the positional information of the patrol car and for example, may be a GPS. The transmitter serves to transmit image information and positional information to an auxiliary location. The input device enables the input of instructions to transmit information via the transmitter. The controller transmits the image information and the positional information via the transmitter after the corresponding instructions are inputted into the input device.  
      Preferably, the image information and the positional information arc transmitted in a single file format or in separate files.  
      In a still further aspect of the present teachings, the imaging system further includes a display device and a buffer memory. The display device functions to display the image information captured by the image pick-up device. The buffer memory serves to temporarily store the image information received from the image pick-up device or read from the memory device The transmitter transmits the image information stored in the buffer memory  
      Preferably, the image information and the positional information are stored in the buffer memory in a file format. The transmitter for example, may be a police radio transmitter.  
      In a still further aspect of the present teachings, patrol cars, such as police cars, are taught that include imaging systems. The imaging systems include at least one image pick-up device, the memory device, and the controller. The at least one image pick-up device is operable to capture images of at least one of either the outside or inside environment of the patrol car and to output the corresponding image information. The memory device serves to store the image information. The controller executes instructions to record the image information in the memory device and to output a synchronization signal to the image pick-up device. Consequently, the image information corresponding to one frame of an image is outputted from the image pick-up device to the controller in response to the cyclic period of the synchronization signal.  
      Therefore, the image information can be captured at the same time interval, according to the synchronization signal, even if a plurality of image pick-up devices are provided. In addition, altering the cyclic period of the synchronization signal conveniently varies the time intervals of the outputs of the image information from the image pick-up devices.  
      In a still further aspect of the present teachings, the patrol cars may additionally include a speed sensor for detecting the traveling speed of the patrol car. The controller is operable to vary the cyclic period of the synchronization signal in response to the detected traveling speed.  
      Therefore, the number of image frames per unit of time captured by the image pick-up device(s) can be altered in response to the traveling speed. For example, the number of frames of images per unit time may be reduced during lower speed traveling and may be increased during high speed traveling.  
      In a still further aspect of the present teachings, the controller monitors the remaining storage capacity of the memory device and indicates information regarding the remaining storage capacity to an operator of the imaging system. For example, such information may be the level of available capacity, a period for exchanging the memory device, or a period available for storing information. Therefore, it is possible to reliably prevent trouble such as the inability to store information in the memory device when an operator desires to store information during patrol.  
      Preferably, the controller monitors the remaining storage capacity each time the engine of the patrol car is started. The controller may output an alert signal if the remaining storage capacity is lower than a predetermined level or if the memory device is not connected to the controller. The inability of information storage can further be reliably prevented with this arrangement.  
      In a still further aspect of the present teachings, the controller includes a control unit and a relay device and executes instructions to store image information in the memory device. The relay device receives a power supply from a battery mounted in the patrol car. The power is supplied to the control unit, the image pick-up device, and the memory device, via the relay device. In addition, the relay device is arranged and constructed so as to control the start-up timing of each of the control unit, the image pick-up device, and the memory device.  
      The control unit, the image pick-up device, and the memory device, can receive a common power supply from the relay device. In a conventional automobile, power is supplied to various electric components via complex circuits including fuses and relays in each of the power supply lines to the electric components. In some cases, any of the individual power supply lines may be interrupted in response to a condition of the automobile In addition, the time or the start-up order or shutdown order of the electric components may be variable. As a result, the operation of the electric components may be unstable. Conversely, according to the present aspect of this invention, it is possible to reliably prevent unstable operation of the control unit, the image pick-up device, and the memory device, because the power is stably supplied via the relay device. Consequently, the imaging system can stably operate.  
      In a still further aspect of the present teachings, the controller includes a reading device that functions to obtain identification information of an operator of the imaging system and to store the read information in the memory device. For example, the reading device may read the identification information of a driver or a passenger of the patrol car. The identification information may be read from an IC tag that stores identification information relating to the person who is using the patrol car. The controller may store the read information and the time of the reading operation in the memory device. Consequently, it is possible to later identify a person who had previously used the patrol by analyzing the information stored in the memory device.  
      In a still further aspect of the present teachings, the controller has an internal clock. The internal clock functions to synchronize the time of the internal clock with the correct time at predetermined intervals. The controller may automatically conveniently perform the synchronizing operation when an engine of the patrol car is started for example. As a result, the accuracy of the time information corresponding to the image information stored in the memory device can be improved. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      FIGS.  1 (A) and  1 (B) are views of image pick-up devices of a first representative embodiment and showing the image pick-up devices respectively mounted on and within a patrol car; and  
       FIG. 2  is a block diagram of the imaging system; and  
       FIG. 3  is a table showing different image pickup modes of the imaging system; and  
       FIG. 4  is a block diagram showing a general construction of second to fourth representative embodiments; and  
       FIG. 5  is an explanatory view showing image information and positional information that are transmitted in the same file; and  
       FIG. 6  is an explanatory view showing image information and positional information that are transmitted in different files; and  
       FIG. 7  is a block diagram similar to  FIG. 4  but showing a fifth representative embodiment; and  
       FIG. 8  is a schematic view of a sixth representative imaging system and illustrating the connecting relation between an image memory section (including a control unit and a relay device) and image pick-up devices; and  
      FIGS.  9 (A) and  9 (B) are views showing the arrangement of the image pick-up devices, the control unit and the relay device on or within a patrol car; and  
       FIG. 10  is a view showing the internal construction of the control unit and the relay device and showing the connecting relation between these devices and the image pick-up devices; and  
       FIG. 11 (A) is a front view of an operation panel of the control unit; and  
       FIG. 11 (B) is a view showing arrangement of a group of operation buttons of the operation panel; and  
       FIG. 11 (C) is a front view of the control unit with the operation panel opened; and  
      FIGS.  12 (A) and  12 (B) are explanatory views showing image information and positional information that are transmitted in the same file according to the sixth representative imaging system; and  
      FIGS.  12 (C) and  12 (D) are explanatory views showing image information and positional information that are transmitted in different files according to the sixth representative imaging system; and  
      FIGS.  13 (A) to  13 (C) are views showing various images displayed on a display device of the sixth representative imaging system. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      Each of the additional features and teachings disclosed above and below may be utilized separately or in conjunction with other features and teachings to provide improved image pick-up devices. Representative examples of the present invention, which examples utilize many of these additional features and teachings both separately and in conjunction with one another, will now be described in detail with reference to the attached drawings. This detailed description is merely intended to teach a person of skill in the art further details for practicing preferred aspects of the present teachings and is not intended to limit the scope of the invention. Only the claims define the scope of the claimed invention. Therefore, combinations of features and steps disclosed in the following detailed description may not be necessary to practice the invention in the broadest sense, and are instead taught merely to particularly describe representative examples of the invention. Moreover, various features of the representative examples and the dependent claims may be combined in ways that are not specifically enumerated in order to provide additional useful embodiments of the present teachings.  
      First Representative Embodiment  
      A first representative embodiment of the present invention will now be described with reference to FIGS.  1 (A) and  1 (B), and  FIGS. 2 and 3 . The general construction of the first representative embodiment will be first described with reference to these drawings.  
      General Construction  
      FIGS.  1 (A) and  1 (B) show different aspects of an image pick-up device  10  of a representative imaging system  1  (see  FIG. 2 ) adapted to be mounted to a patrol car S (a police car in this representative embodiment). In  FIG. 1 (A), the image pick-up device  10  is mounted to an external surface of a vehicle roof R, in order to capture images of the external environment of the patrol car S. The image pick-up device  10  is covered by a protective cover  10   z  in order to prevent or minimize the influence of the outside conditions, such as the weather, upon the image pick-up device  10 . The image pick-up device  10  has an optical axis CZ. The orientation of the optical axis CZ can be changed with regard to the horizontal direction and the vertical direction.  
      In  FIG. 1 (B), the image pick-up device  10  is mounted to an inner surface of the front portion of the vehicle roof R, in order to take up images of the inside of the patrol car S. In particular, this image pick-up device  10  is configured so as to capture the images of a passenger seated on a rear seat (not shown) of the patrol car S.  
      As shown in  FIG. 2 , the image pick-up device  10  may be a camera, such as a CCD camera. The image pick-up device  10  may output image information (taken at predetermined time intervals) to an image compression device  30   b  of a control unit  30 . The image pick-up device  10  has a zooming device  10   a  and a direction changing device  10   b . The zooming device  10   a  is operable to change the focal length of the image pick-up device  10 . The direction changing device  10   b  is operable to change the direction (angle) or orientation of the optical axis CZ with respect to the horizontal direction and the vertical direction. A CPU  30   a  controls the zooming device  10   a  and the direction changing device  10   b.    
      The control unit  30  has an expansion device  30   c  in addition to the CPU  30   a  and the compression device  30   b . Therefore, the image information outputted from the image pick-up device  10  is compressed by the compression device  30   b  before inputting the information to the CPU  30   a . The image information inputted to the CPU  30   a  is thereafter stored in a memory device  50  (e.g., a hard disc drive (HDD)). In addition, the image information inputted to the CPU  30   a  may be expanded by the expansion device  30   c  in order to be outputted to a display device  40  (e.g., an LCD). An operation panel  20  may be mounted within the interior of the cabin of the patrol car S. The operation panel  20  may output an operation signal to the control unit  30  so that the CPU  30   a  reads the image information stored in the memory device  50 , and subsequently outputs the read information to the display device  40  via the expansion device  30   c.    
      Various sensors  60   a  to  60   n  (e.g. a traveling speed sensor) and a functional unit  60  (e.g. a navigation unit) may be mounted on or within the patrol car S. The control unit  30  can obtain various types of information regarding the patrol car S associated with the control unit  30 , from the sensors  60   a  to  60   n  and the functional unit  60 . For example, the control unit  30  may be directly connected to the sensors  60   a  to  60   n  and the functional unit  60 . Otherwise, the control unit  30  may be connected to the functional unit  60  via an in-vehicle LAN. In this way, the control unit  30  can monitor and record information regarding patrol car S.  
      The imaging system  1 , in particular the operation mode of the image pick-up device  10  can be automatically changed between various image capturing modes, as shown in  FIG. 3 , in response to various traveling conditions of the patrol car S. In  FIG. 3 , an elevation angle and a rotation angle may be controlled by the direction changing device  10   b.  Zooming is controlled by the zooming device  10   a.    
      In response to the desired image pick-up or capturing modes, the image pick-up device  10  may be mounted to only the outside of the vehicle as shown in  FIG. 1 (A), mounted to only the inside of the vehicle as shown in  FIG. 1 (B), or mounted to both the interior and exterior of the patrol car S. However, for the purposes of explanation, the image pick-up modes will be described with reference to  FIG. 3  assuming that the image pick-up device  10  is mounted to the inside and the outside of the patrol car S. In  FIG. 3  is a table  100  in which the controls performed in image pick-up modes  1  to  8  are respectively listed in rows  101  to  108 .  
      (First Image Pick-Up Mode)  
      In the first image pick-up mode, control of the image pick-up devices  10  is performed based upon the capacity of a power source, such as an in-vehicle battery. Unlike a commercial power source, the voltage of the in vehicle battery may abruptly change in response to the operating conditions of the vehicle and the environment (such as ambient temperature). Therefore, in order to operate in the first image pick-up mode, at least one of the sensors  60   a  to  60   n  is configured as a voltage sensor able to detect the voltage level of the power source. As shown in the first row  101  of the table  100  in  FIG. 3 , the control unit  30  determines the power source voltage based upon the signal from the voltage sensor or based upon a signal from the functional unit  60 , to which the voltage sensor may be connected. If the power source voltage is lower than a predetermined voltage value, such as 8V, the control unit  30  stops the image capturing operation by the inside image pick-up device  10 . Then only the image pick-up device  10  mounted to the outside of the patrol car S operates to pick up images. In addition, the control unit  40  stops the operations for controlling the elevation angle, the rotation angle, and the zooming ability of the outside image pick-up device  10 .  
      (Second Image Pick-Up Mode)  
      In the second image pick-up mode, as shown in the second row  102  of table  100 , the control unit  30  determines if a passenger is seated on the rear seat(s). If that determination is YES, the control unit  30  instructs the inside image pick-up device  10  to capture the image of the passenger(s) on the rear seat(s) and also to record the image in order to operate in the second image-pick up mode, the sensors  60   a  to  60 n may include at least one passenger sensor that is operable to detect a passenger(s) seated on the rear seat(s). The control unit  30  may determine the presence of the passenger(s) on the rear seat(s) via the signal from the passenger sensor or via a signal from the functional unit  60  to which the passenger sensor may be connected. The inside image pick-up device  10  may capture the image with the elevation angle and the rotation angle fixed so as to orient the image pick-up device  10  towards the rear seats. In addition, the zooming may be fixed to a relatively wide angle. As examples, the passenger sensor may be a seating detection sensor (i.e., a pressure or weight sensor), an infrared sensor, or any other suitable sensor.  
      (Third Image Pick-Up Mode)  
      In the third image pick-up mode, the control unit  30  determines if the patrol car S is operating under emergency conditions, such as illuminating a rotary lamp and sounding a siren, as shown in the third row  103  of table  100 . In order to operate in the third image pick-up mode, the sensors  60   a  to  60   n  may include an emergency sensor for detecting the lighting of the rotary lamp or a sensor for detecting the sounding of a siren. The control unit  30  may determine the emergency condition based upon a signal from the emergency sensor or a signal from the functional unit  60  to which the emergency sensor may be connected. If the determination is YES, the elevation angle of the outside image pick-up device  10  may be set to an angle of 0°. The rotating angle may be directed towards the traveling direction of the patrol car S. The zooming may be fixed to an equi-magnification (i.e., a one to one size relationship between the image viewed by a person and the image captured by the image pick-up device  10 ).  
      (Fourth Image Pick-Up Mode)  
      In the fourth image pick-up mode, the control unit  30  determines if the patrol car S is traveling at a speed exceeding a predetermined traveling speed, as shown in the fourth row  104  of table  100 . If the traveling speed exceeds the predetermined speed, the horizontal direction of the outside image pick-up device  10  is changed so as to follow the direction corresponding to the steering angle. In order to operate in the fourth image pick-up mode, the sensors  60   a  to  60   n  may include a speed sensor and a steering angle sensor. The control unit  30  may determine if the traveling speed exceeds the predetermined speed based upon the signal from the speed sensor or a signal from the functional unit  60  to which the speed sensor may be connected. For example, the predetermined traveling speed may be 80 km/h. If the determination is YES (i.e., the actual vehicle speed exceeds 80 km/h in this example), the elevation angle of the outside image pick-up device  10  may be set to an angle of 0°. The zooming is fixed to an equi-magnification (i.e., a one to one size relationship between the image viewed by a person and the image captured by the image pick-up device  10 ). The rotation angle may be changed to correspond to the steering angle detected by the steering angle sensor.  
      Therefore, it is possible to capture and record images of the outside environment substantially in the focusing direction of the eyes of the driver of the patrol car S as the patrol car S is rushing to the scene.  
      (Fifth Image Pick-Up Mode)  
      In the fifth image pick-up mode as shown in the fifth row  105  of the table  100 , the control unit  30  determines if the patrol car S has stopped after traveling. In order to operate in the fifth image pick-up mode, the sensors  60   a  to  60   n  may include a speed sensor, as in the fourth mode. The control unit  30  may determine if the patrol car S has stopped after traveling (i.e., if the traveling speed has been changed from a value (absolute value) of more than zero, to zero) based upon the signal from the speed sensor or a signal from the functional unit  60  to which the speed sensor may be connected. If the determination is YES, the elevation angle of the outside image pick-up device  10  may be set to an angle of 0°. The rotation angle may be set to an angular rate of 360°/30 sec in the right-hand direction (clockwise in this example). The zooming may be set for a wide-angle view.  
      Therefore, after rushing to the scene it is possible to automatically capture and record images of the outside environment around the scene when the patrol car S has stopped. In addition, when the patrol car S has stopped at an intersection for example, the images of the environmental conditions around the stopped car, such as the condition of the weather, people, and vehicles in the vicinity can be automatically picked up and recorded. This could increase the possibility that a policeman could record worthwhile images for later reference in the case at some time after the patrol without having to manually operate the image pick-up device  10 .  
      (Sixth Image Pick-Up Mode)  
      The sixth image pick-up mode is similar to the fifth image pick-up mode in that the control unit  30  determines if the patrol car S has stopped after a period of traveling. However, the sixth image pick-up mode is different from the fifth image pick-up mode in that the control unit  30  determines if the patrol car S has stopped within a predetermined district, as shown in the sixth row  106  of the table  100 . In order to operate in the sixth image pick-up mode, the sensors  60   a  to  60   n  may include a speed sensor as in the fourth mode. In addition, the functional device  60  may be a navigation unit that outputs a location signal to the control unit  30 . The location signal from the navigation unit allows the control unit  30  to determine if the stopped position is within the predetermined district. If the control unit  30  determines that the patrol car S has stopped within the predetermined district after traveling, the elevation angle of the outside image pick-up device  10  may be set to an angle of 0°. The rotation angle may be set to an angular rate of 360°/60 sec in the right-hand direction. The zooming may be set to a twice-magnification zoom.  
      Therefore, by setting the scene as the predetermined district, it is possible to inhibit the sixth image pick-up mode imaging operation when the patrol car S has temporarily stopped along the way while otherwise rushing to the scene. In addition, by setting the predetermined district to the urban district, it would be possible to inhibit the sixth image pick-up mode imaging operation during a patrol of the suburban district. In many cases, the images of the environment surrounding a scene located in the suburban district are not worthwhile.  
      (Seventh Image Pick-Up Mode)  
      In the seventh image pick-up mode, the control unit  30  determines if a signal is being transmitted from an information transmitter (not shown) as listed in the seventh row  107  of table  100 . For example, the policeman driving or riding in the patrol car S may hold the information transmitter. In addition, the information transmitter may be attached to a target to be traced. In order to operate in the seventh image pick-up mode, the functional unit  60  may be a receiver able to receive the signal from the information transmitter or the functional unit  60  may be a navigation unit. If the functional unit  60  is a receiver, the receiver may output a signal representing the direction of the transmission of the signal from the transmitter. If the functional unit  60  is a navigation unit, the navigation unit may also output a signal representing the direction of transmission of the signal from the transmitter based upon the information regarding the position of the transmitter and the information regarding the position of the patrol car S. Such a signal representing the transmitter signal transmission direction may be inputted into the control unit  30 . In this way, if the control unit  30  determines that a signal is being transmitted from the transmitter, the elevation angle of the outside image pick-up device  10  may be set to an angle of 0°. The zooming may be set to a wide angle. The turning angle may be set to an angle corresponding to the transmitter signal transmission direction so as to direct the image pick-up device  10  towards the transmitter.  
      For example, if the policeman holds the transmitter, the image pick-up device  10  may be directed to him or her. If the transmitter is attached to a target, such as the trunk of a target automobile to be traced, the image pick-up device  10  may be directed to the target automobile.  
      (Eighth Image Pick-Up Mode)  
      In the eighth image pick-up mode, the control unit  30  determines if a signal is being received from a police radio transmitter (not shown) of another policeman, another police car, or a host police station, as shown in the eighth row  108  of table  100 . In order to operate in the eighth image pick-up mode, the functional unit  60  may be a receiver for receiving the police radio transmitter signal. If the functional unit  60  is a receiver, the receiver may output a signal representing the transmission direction of the transmitter signal. Such a signal representing the transmission direction of the transmitter signal may be inputted to the control unit  30 . In this way, if the control unit  30  determines that a signal is being transmitted from the police radio transmitter, the elevation angle of the outside image pick-up device  10  may be set to an angle of 0°. The zooming may be set to a wide angle. The turning angle may be set to an angle corresponding to the transmission direction of the police radio transmitter signal so as to direct the image pick-up device  10  toward the transmitter in the same manner as in the seventh representative embodiment.  
      (Parameters Changed in Response to Various Image Pick-Up Modes)  
      As described above, the parameters changed in response to the first to eighth image pick-up modes may include at least one of the focusing distance of the inside or outside image pick-up device  10 , the angle within the horizontal plane of the inside or outside image pick-up device  10 , and the angle within the vertical plane of the inside or outside image pick-up device  10 . The focusing distance may be changed by the zooming device  10   a.  The horizontal and vertical angles may be changed by the direction change device  10   b.    
      (Possible Alternative Arrangements of the First Representative Embodiment)  
      The present invention may not be limited to the representative imaging system  1  but may be modified in various ways as will be hereinafter described.  
      (1) The imaging system  1  is not necessary to operate in all of the above first to eighth image pick-up modes. Thus, the imaging system  1  may be constructed to operate in at least one of the image pick-up modes. If the imaging system  1  is constructed to operate in all of the above first to eighth modes, the process starting conditions shown in the first row  101  to the eighth row  108  of table  100  of  FIG. 3  may be serially performed in order from the first row  101  to the eighth row  108   
      (2) Although the first representative embodiment has been described in connection with the representative imaging system  1  that includes the inside and outside image pick-up devices  10 , the imaging system  1  may have only one of either the inside or outside image pick-up devices  10  in response to the desired image pick-up modes. For example, the imaging system  1  can operate in the first and third to eighth modes even if the imaging system  1  has only the outside image pick-up device  10 . Alternatively, the imaging system  1  can operate in the second mode if the imaging system has only the inside image pick-up device  10 .  
      (3) The process starting conditions and the method steps (for controlling the elevation angle, the turning angle, and the zooming angle) may not be limited to those shown in  FIG. 3  but may be modified in various ways In addition, the numerical values indicated in the above representative embodiment should be considered to be possible example values and are not intended to limit the invention.  
      Second to fifth representative embodiments will now be described with reference to FIGS.  4  to  7 .  FIG. 4  shows the general construction of the second to fourth representative imaging systems. Referring to  FIG. 4 , a patrol car  100 , such as a police car, has various in-vehicle devices. The various in-vehicle devices include three image pick-up devices  11   a,    11   b,  and  11   c  such as video cameras, a switching device  12 , a positional information acquisition device  13  such as a GPS, a control unit  14 , and a transmitter  15  such as a radio transmitter.  
      Second Representative Embodiment  
      The second representative imaging system is configured to transmit the image information picked up by the image pick-up devices  11   a,    11   b  and  11   c,  together with the positional information from the positional information acquisition device  13 , in the same file for example.  
      The image pick-up device  11   a  is mounted within the patrol car  100  and is positioned to record images of the environment to the front of the patrol car  100 , over the windshield (not shown in  FIG. 1 ) of the patrol car  100 . Each time the image is picked up by the image pick-up device  11   a  during a predetermined time, the image is transmitted to a compression device  14   a  of the control unit  14 . The compression device  14   a  receives the images as image information consisting of a series of continuous frames of still images or a video image. The image pick-up device  11   b  is also mounted within the patrol car  100 . Image pick-up device  11   b  is positioned to capture images of the environment to the rear of the patrol car  100  through the rear window (not shown in  FIG. 1 ) of the patrol car  100 . Similarly, the image pick-up device  11   c  is mounted within the patrol car  100 . Image pick-up device  11   c  is positioned to capture images in the general location of the rear seat(s) of the patrol car  100 . Each time an image is recorded by the image pick-up device  11   b  or  11   c  during a predetermined time, the image is transmitted to a compression device  14   b  of the control unit  14 . The compression device  14   b  receives images as image information consisting of a series of continuous frames of still images or a video image. Thus, the switching device  12  operates to selectively transmit either the image information from the image pick-up device  11   b  or the image information from the image pick-up device  11   c  to the compression device  14   b . If the compression device  14   b  is configured as a video image compression device, the compression device  14   b  may compress the received image information into compressed video image information, such as MPEG. If the compression device  14   b  is configured as a still image compression device, the compression device  14   b  may compress the received image information into compressed still image information, such as JPEG.  
      As described previously, the positional information acquisition device  13  may be a GPS that is known to receive information from an artificial satellite in order to enable identification of the current location of the GPS itself via a position representing signal (i.e., a signal representing latitude and longitude positions). If the GPS is configured to store address information related to the position representing signal, it is possible to identify the current position as a current address. The address information may be transmitted to the CPU  14   c  of the control unit  14 . As described above, the control unit  14  includes the compression devices  14   a  and  14   b , and the CPU  14   c.  In addition, the control unit  14  includes an input device  14   d,  a display device  14   e,  a buffer memory  14   f,  and a memory device  14   g.    
      Each time the compression device  14   a  receives the image information that corresponds to one frame of the still images that are continuously recorded by the image pick-up device  11   a  at predetermined time intervals (e.g., {fraction (1/60)} seconds), the compression device  14   a  compresses the received image information (i.e., the still image) and temporarily stores the compressed image information in the compression device  14   a . When the amount of stored image information has reached a predetermined amount (such as a predetermined number of frames, e.g., five frames, of the still images), the compression device  14   a  transmits the predetermined amount of stored image information to the CPU  14   c  as a batch of image signals. Assuming that the switching device  12  has been switched so as to transmit the image information from the image take-up device  11   b  to the compression device  14   b , the compression device  14   b  compresses and stores the image information corresponding to one frame of the still images captured by the image pick-up device  11   b  each time the compression device  14   b  receives image information corresponding to one frame. The compression device  14   b  transmits the stored information to the CPU  14   c  as a batch of image signals when the amount of stored information has reached a predetermined amount, such as a predetermined number of frames, e.g., five frames, of the still images.  
      When the CPU  14   c  receives the batch of image signals from each of the compression devices  14   a  and  14   b , the CPU  14   c  affixes first and second information to each image signal in such a manner that the first and second information are included in the header of each image signal. First information relates to the identification number to identify each of the corresponding image pick-up device  11   a,    11   b,  and  11   c.  Second information relates to the time that the image was captured to identifying the recording time of the received information. The CPU  14   c  then transmits the image information, which includes the image signals each having the first and second information and any other attribute information, in the header, to the buffer memory  14   f,  so as to be stored therein. The system also may include a clock device in order to identify the current time. In addition, the CPU  14   c  stores the positional information (obtained by the GPS  13 ) in a file format in the buffer memory  14   f,  together with the above image information.  
      The image information combined with the positional information may be stored in the buffer memory  14   f  in a configuration schematically shown in  FIG. 5 . As shown in  FIG. 5 , the image information has an image signal with the first and second information (the image pick-up device identification number and the time of the image capture) included in the header of the image signal. In addition, positional information is affixed to the header of the image signal. Therefore, the image can be readily identified as to the image pick-up device used to capture the images and as to the time the image information was captured, by referring to the header of the image signal.  
      Preferably, the information may be stored in the buffer memory  14   f  in an overwrite manner. Consequently, as new information is received, the previous information is erased and the new information is overwritten in the memory section where the previous information had been stored. Therefore, the image information and the positional information once stored in the buffer memory  14   f  may in turn be stored in a memory device  14   g,  such as a HDD (Hard Disk Drive). In addition, the display device  14   e  may simply display the video images taken by each of the image pick-up devices  11   a,    11   b,  and  11   c,  without any additional information. Further, the CPU  14   c  may operate so as to search or read particular image information from the memory device  14   g,  based upon a search condition such as tho image pick-up device number and the capture time. The read image information may then be displayed on the display device  14   e.    
      Further, even if it is not possible to write the information in the memory device  14   g , for example due to the vibrating of the patrol car  100 , such information may be temporarily stored in the buffer memory  14   f  until the conditions affecting the memory device  14   g  have been changed to enable a writing operation. Therefore, the image information and the positional information may be stored without significant omissions, even if vibrations have been produced during the traveling of the patrol car  100 . In this connection, the capacity of the buffer memory  14   f  may be conveniently determined by taking into account the possible duration of vibrations. For example, the duration of vibrations may be the duration required for the patrol car  100  to ride over a possible stepped surface on the road.  
      Furthermore, when an input operation is made by means of an input device  14   d , such as a push button, the CPU  14   c  operates to combine the image information stored in the buffer memory  14   f  and the positional information (that may be stored in the same buffer memory  14   f  or may be stored in another memory device) in the same file and transmit the file to a receiver  31  of a fixed station  29 , such as a police station, via a radio transmitter  15 . Therefore, in a state of emergency, the fixed station  29  can receive the image information picked up by the controlled police car and can also receive the positional information related to the image information.  
      Thus, if a matter of emergency has arisen during the patrol by the patrol car  100  while the image of the environment is being captured by the in-vehicle imaging system, image information including the image information of the scene and the most current image information can be readily transmitted to the police station by the operation of the input device  14   d  in the patrol car  100 . Therefore, persons in the police station can readily visually recognize the actual scene situation in order to issue appropriate instructions to the policemen at the scene. In addition, they can immediately send necessary backup cars to the scene, because the capturing location of the image can be readily recognized. Since the image information and the positional information are transmitted in the same file, the image information and the positional information can be handled as one file of information. Consequently, the one file of information facilitates the handling and management of the information.  
      Furthermore, the control unit  14  may be mounted within a storage space that is normally provided in the automobile for storing the main body of audio equipment. Therefore, if the main body of the audio equipment has already been installed, the control unit  14  may be mounted within the storage space after removing the audio equipment. In addition, audio equipment may be assembled together with the control unit  14  and may then be mounted within the empty storage space.  
      It is typically not possible to mount a conventional control unit within the storage space used for the installation of the main body of audio equipment because the size of a conventional control unit is relatively large. Therefore, the control must be mounted to another portion, such as the dashboard of the automobile. This may obstruct the driver&#39;s view and may hinder the driving operation of the driver. Further, the operability of the control unit is degraded because the driver may not be able to easily access the control unit. Conversely, the control unit  14  of this representative embodiment can be designed to have a small size in order to mount within the storage space prepared and designed for the main body of audio equipment. The representative embodiment is effective and advantageous in that the operability of the control unit  14 , as well as the other in-vehicle devices that are necessary for police service, can be improved  
      Third Representative Embodiment  
      The third representative imaging system differs from the second representative embodiment in that the image information picked up by the image pick-up devices  11   a,    11   b,  and  11   c,  is transmitted in a separated file apart from the positional information determined by the positional information acquisition device  13  (i.e., GPS). However, the components of the third representative embodiment are substantially the same as those of the second representative embodiment, which were described with reference to  FIG. 4 . Therefore, the third representative embodiment will be described with respect to only the transmission of the information file.  
      Similar to the second representative embodiment, the CPU  14   c  issues instructions to store the image information in the buffer memory  14   f , preferably together with the positional information. The positional information may be stored in another memory device (not shown). In this representative embodiment, as shown in  FIG. 6 , the positional information is stored in a separate file apart from the file in which the image information is stored. Similar to the first representative embodiment, the image information has the image signal with the first and second information (i.e., the image pick-up device identification number and the time the image was captured) included in the header of the image signal. In this representative embodiment, the first and second information also are affixed to the positional information as shown in  FIG. 6  The image information and the positional information are stored in the memory device  14   g  in the form of separate files and are transmitted to the receiver  31  also in the form of separate files. The image information and the positional information can be correlated to each other via the first and second information affixed to the information files.  
      Therefore, if it is desired to obtain the positional information from the image information, an operator may first identify the first and second information included in the image information. Next the operator may conduct a search for the positional information that matches the first and second information identified from the image information. The operator can subsequently identify the image capturing location from the located positional information that may be displayed on the display device  14   e . Conversely, it is also possible to obtain the image information from the positional information by using a similar method.  
      In addition, the separation of files may reduce the amount of information included in the header of the information signal because only the first and second information are included in the header.  
      Fourth Representative Embodiment  
      The fourth representative imaging system is different from the first and second representative embodiments in that the image information captured by the image pick-up devices  11   a,    11   b,  and  11   c,  and the positional information from the positional information acquisition device  13  (GPS), are sequentially transmitted. However, the components of the third representative embodiment are substantially the same as those of the second representative embodiment, which were described with reference to  FIG. 4 . Therefore, the fourth representative embodiment will primarily be described with respect to the transmission of information.  
      Similar to the second and third representative embodiments, the CPU  14   c  issues instructions to store the image information in the buffer memory  14   f , preferably together with the positional information. However, the image information and the positional information are sequentially stored in the buffer memory  14   f . Therefore, the CPU  14   c  issues instructions to perform the following steps. When the CPU  14   c  receives a predetermined amount of image information (i.e., a predetermined number of image frames) from the compression device  14   a , the CPU  14   c  issues instructions to store such image information in the buffer memory  14   f . Subsequently, the CPU  14   c  also issues instructions to store the positional information and the second information (capture time of the image) related to the stored image information. Similarly, when the CPU  14   c  receives a predetermined amount of image information (i.e., predetermined number of image frames) from the compression device  14   b , the CPU  14   c  issues instructions to store such image information in the buffer memory  14   f . Subsequently, the CPU  14   c  issues instructions to store the positional information and the second information (capture time of the image) related to the stored image information.  
      More specifically, six pieces of information, including the image information, related positional information, and second information (capture time) from the compression device  14   a , and the image information, related positional information, and second information (capture time) from the compression device  14   b , are sequentially stored as a block in the buffer memory  14   f . The six information pieces are continuously handled as a block in further processing. Consequently, the information may be stored in the memory device  14   g  and may be transmitted to an external fixed location (e.g. the police station  29 ) in unit of a block consisting of six pieces of information.  
      Fifth Representative Embodiment  
      The fifth representative imaging system will now be described with reference to  FIG. 7 . The fifth representative imaging system is a modification of the second representative embodiment. Therefore, in  FIG. 7 , like elements are labeled with the same reference numerals as in the second representative embodiment. As shown in  FIG. 7 , according to the fifth representative embodiment, the CPU  14   c  is connected to various terminal devices (such as the image pick-up devices  11   a,    11   b,  and  11   c , the switching device  12 , the positional information acquisition device  13 , and the transmitter  15 ) via a relay device  16 . In other words, the relay device  16  serves as an interface between the control unit  14  and the terminal devices. More specifically, the image pick-up devices  11   a  is connected to the control unit  14  via a relay device  16 . The image pick-up devices  11   b  and  11   c  are connected to the control unit  14  via the switching device  12  and the relay device  16 . The positional information acquisition device  13  (GPS) and the transmitter  15  are connected to the relay device  16 . In other respects, the configuration of the fifth representative embodiment is the same as the first representative embodiment.  
      According to the imaging system of the fifth representative embodiment, a portion of the control panel of the control unit  14 , in particular the display device  14   e  may be mounted within the storing space allocated for mounting audio equipment. The other part of the control panel may be placed on the floor, within the trunk, or any other convenient place. With this arrangement, an operator who is sitting on the driver&#39;s seat or a passenger&#39;s seat can easily access the part of the control panel that is to be operated for police service functions. In addition, the other part of the control panel can be conveniently mounted in another area of the patrol car  100 , because of an increased freedom of choice for placing the remaining part of the control panel.  
      Also with the fifth representative embodiment, the image information and the positional information can be transmitted in the same file in the same manner as in the second representative embodiment, or transmitted in separate files in the same manner as in the third representative embodiment (except for including the intervention of the relay device  16 ). In addition, it is also possible to sequentially transmit the information as a block of six pieces of information in the same manner as in the fourth representative embodiment.  
      Preferably, the relay device  16  may be mounted on the dashboard within the patrol car  100 . With this arrangement, cables extending from the terminal devices can be easily connected to and removed from the relay device  16 . In addition, the relay device  16 , mounted on the dashboard, may have a relatively small size because the main part of the control unit  14  is installed within the storing space of the audio equipment, i.e., within the instrumental panel. Although not shown in the drawings, some examples of additional terminal devices that may also be connected to the relay device  16  are a sound-collecting device (e.g., a microphone), an in-vehicle speaker, an emergency light, and a speed detection device for detecting the traveling speed of a preceding automobile.  
      (Possible Alternative Arrangements of the Second to Fifth Representative Embodiments)  
      Although the second to third representative embodiments have been described in connection with the imaging system as having three image pick-up devices, the number of image pick-up devices is not limited to three but may be one, two, or four or more. In addition, a new or existing in-vehicle navigation device may be used as the positional information acquisition device. Further, by incorporating a sound-collecting device, the sound may be captured by the collecting device and may be recorded as sound information together with the image information In such a case, the sound-collecting device may be connected to the CPU  14   c  of the control unit  14  via the relay device  16 . Furthermore, by connecting the speed sensor of the patrol car  100  to the CPU  14   c , it is possible to record the speed of the patrol car  100  together with the image information.  
      Sixth Representative Embodiment  
      A sixth representative imaging system will now be described with reference to FIGS.  8  to FIGS.  13 (A),  13 (B), and  13 (C).  FIG. 8  shows a general construction of the sixth representative imaging system that is mounted on a patrol car S 1 , such as a police car (see FIGS.  9 (A) and  9 (B).  
      (Construction of Imaging System and Connection Network)  
      Similar to the fifth representative embodiment, the imaging system includes a control unit  130 , a relay device  120 , and image-pick up devices  110   a ,  110   b,  and  110   c,  such as CCD cameras. In this representative embodiment, a memory device  135 , such as a HDD, is mounted within the control unit  130 . The control unit  130  also has a display device  136 .  
      The image pick-up devices  110   a,    110   b,  and  110   c,  are connected to the relay device  120 , so that the image information captured by the image pick-up devices  110   a ,  110   b , and  110   c,  are inputted to the relay device  120 . The relay device  120  compresses the inputted image information. The compressed image information is then inputted to the control unit  130  via a LAN cable (not shown) or any other suitable transmission device. The control unit  130  issues instructions to control the direction and/or the zooming angle of each of the image pick-up devices  110   a ,  110   b,  and  110   c,  and to record the image information inputted from the relay device  120  in response to the operation of the control unit  130  by the driver or a passenger of the patrol car S 1 . Also in this representative embodiment, the number of image pick-up devices is not limited to three but may be one, two, or four or more.  
      In this representative embodiment, the patrol car S 1  is designed to have various police service equipment, such as a radar  140   w,  an external speaker  140   x,  a rotary lamp  140   y,  and a microphone  140   z.  The radar  140   w  may be used for measuring the traveling speed of a target automobile. The external speaker  140   x  may be used for emitting alert sounds, a siren, or voice commands. The rotary lamp  140   y  may be used for emitting an alert or emergency light. The microphone  140   z  may be used for inputting a users voice to the external speaker  140   x.  A positional information acquisition device  140   a , such as a GPS, may also be connected to the relay device  120 . In addition, a sensor  140   b , such as a speed sensor of the patrol car S 1 , may be connected to the relay device  120 . Therefore, the positional information of the patrol car S 1 , the speed information of a target automobile, and optional information, such as the speed of the patrol car S 1 , may be respectively inputted into the relay device  120  from the positional information acquisition device  140   a , the radar  140   w,  and the sensor  140   b.    
      The relay device  120  may have at least one USB (Universal Serial Bus) terminal so that external devices, such as a terminal device  140   c  (a personal computer in this representative embodiment) and an external memory device  140   d  can be connected to the USB terminal(s) of the relay device  120  via a communication line. More specifically, the image information and/or any other information can be transmitted between a USB communication interface  124  (see  FIG. 10 ) of the relay device  120  and the external devices via the communication line. In addition, the relay device  120  may be connected to a battery  140   e  of the patrol car S 1 . Power is supplied from the battery  140  to the relay device  120  and further to the control unit  130  and the image pick-up devices  110   a  to  110   c.  In addition to the devices noted above, various external devices can be connected to the USB terminal(s). For example, a printer having a USB communication interface may be directly connected to the USE terminal. Preferably, the control unit  130  may include an operation button(s) that is actuated by an operator (the driver or a passenger) for selecting and printing desired documents or images.  
      The control unit  130  is designed so as to allow the memory device  135  to be mounted within the control unit  130 . The control unit  130  may be operable by the driver or a passenger of the patrol car S 1  in order to record the image information outputted from the relay device  120  to the built-in memory device  135  or an external memory device  140   d  connected to the relay device  120 . In addition, the control unit  130  is designed to enable the desired image information or any other information to be received and transmitted as a result of radio communication via an antenna  138 , due to the driver or a passenger of the patrol car S 1  operating the control unit  130 .  
      In this representative embodiment, the control unit  130  is also designed to mount a radio receiver  137  (see  FIG. 10 ), so that radiobroadcast voice information received by the antenna  138  can be outputted from the speaker  140   f.    
      (Arrangement of Image Pick-Up Devices, Control Unit and Relay Device)  
      The arrangement of the image pick-up devices  110   a  to  110   c,  the control unit  130 , and the relay device  120 , on or within the patrol car S 1  will now be described with reference to FIGS.  9 (A) and  9 (B).  
      The image pick-up device  110   a  is mounted on the patrol car S 1  in a position suitable for capturing images of the outside environment to the front of the patrol car S 1 . More specifically, as shown in  FIG. 9 (A), the image pick-up device  110   a  is mounted on the front portion of the outer surface of the roof F 1  of the patrol car S 1 . In addition, the image pick-up device  110   a  is covered by a dome-like cover  110   z,  and can pivot within a horizontal plane and a vertical plane in order to change the direction or orientation of an optical axis CZ 1 . In addition, the image pick-up device  110   a  is operable to change the zooming angle or degree of magnification within a predetermined range. The driver or a passenger of the patrol car S 1  can control the orientation of the optical axis CZ 1  and the zooming angle by means of the control unit  130 . Although not shown in the drawings, the image pick-up device  110   a  may also be mounted within the patrol car S 1 , so that the image pick-up device  110   a  can capture the images of the outside environment through the windshield of the patrol car S 1 .  
      The image pick-up device  110   b  is mounted on the patrol car S 1  in a position for capturing images of the outside environment to the rear of the patrol car S 1 . More specifically, as shown in  FIG. 9 (A), the image pick-up device  110   b  is mounted on the rear portion of the outer surface of the roof F 1  of the patrol car S 1 . Similar to the image pick-up device  110   a,  the direction of the optical axis CZ 1  and the zooming angle of the image pick-up device  110   b  can be controlled by the driver or a passenger of the patrol car S 1 , by means of the control unit  130 . Although not shown in the drawings, the image pick-up device  110   b  may be mounted within the patrol car S 1 , so that the image pick-up device  110   b  can capture the images of the outside environment through the rear window of the patrol car S 1 .  
      The image pick-up device  110   c  is mounted within the patrol car S 1  in a position for capturing images of the passenger(s) seated on the rear seat(s) of the patrol car S 1  from the position forward of the rear seat(s). More specifically, as shown in  FIG. 9 (B), the image pick-up device  110   c  is mounted on the interior headliner trim of the patrol car S 1 , for example, in a position proximal to the rear view mirror. The driver or a passenger of the patrol car S 1  can control the direction of the optical axis CZ 1  and the zooming angle of the image pick-up device  110   c  by means of the control unit  130 . However, the distance between the image pick-up device  110   c  and the target may not substantially change over a period of time. Therefore, the zooming angle of the image pick-up device  110   c  may be fixed at a wide angle. In addition, the direction of the optical axis CZ 1  may also be fixed in a predetermined direction.  
      As described in connection with the previous representative embodiments, audio equipment is conventionally mounted within a storage space provided in the dashboard. For example, such a storage space is generally provided in the center console of the dashboard. The control unit  130  may be mounted within the storage space in place of the audio equipment. Alternatively, the radio receiver  137 , shown in  FIG. 10 , may be mounted within the storage space. Of course, the control unit  130  may include other audio devices than the radio receiver  137 .  
      With this arrangement, as described in connection with the previous representative embodiments, the control unit  130  may be positioned such that the operator (i.e., the driver or a passenger) of the control unit  130  can easily access the control unit  130  by simply reaching with his or her hand for changing the direction or orientation of the optical axes CZ 1  and/or the zooming angle of each of the image pick-up devices,  110   a  to  110   c.  In addition, the operator can operate the radio receiver  137  by means of an input device  134  and a CPU  131 .  
      As shown in  FIGS. 8 and 10 , various sensors and devices are connected to the relay device  120 . The various sensors and devices may include those that cannot be mounted within the limited space of the dashboard.  
      In this representative embodiment, the relay device  120  is disposed within a space on the front side of the passenger&#39;s seat as shown in  FIG. 9 (B). However, the relay device  120  may be disposed at any other suitable location. For example, the relay device  120  may be placed below the passenger&#39;s seat, inside of the roof, on the dashboard, within the glove box, or within the trunk.  
      (Operations Performed by the Operator and Internal Construction And Operations of the Relay Device and Control Unit)  
      The operations performed by the operator (i.e., the driver or a passenger of the patrol car S 1 ) and the functioning of the relay device  120  and the control unit  130  based upon the operations performed by the operator will now be described with reference to  FIG. 10  and  FIG. 11 (A).  FIG. 10  and  FIG. 11 (A) respectively show a block diagram of the imaging system and the front view of the operation panel  130 p of the control unit  130 .  
      As shown in  FIG. 11 (A), the display device  136  is positioned on the upper left side of the operation panel  130   p.  Various operation buttons, including a first button group grp 1  and a second button group grp 2 , are respectively disposed on the right side and the lower side of the operation panel  130   p.  Therefore, if the driver seat is positioned on the left side of the operation panel  130   p,  the driver can easily watch the display of the display device  136  while the passenger can easily access and operate the operation buttons.  
      In  FIG. 10 , the marks ⊚, indicated with respect to the relay device  120  and the control unit  130 , represent connectors. The relay device  120  and the control unit  130  are easily connected to and disconnected from each other via the connectors. In addition, other related devices, such as image pick-up devices  110   a  to  110   c  and the positional information acquisition device  140  can be easily connected and disconnected to the system via the connectors.  
      In this representative embodiment, the images of the outside environment are captured by two image pick-up devices  110   a  (front side) and  110   b  (rear side), while the images of the rear seat(s) within the patrol car S 1  is captured by one image pick-up device  110   c.  However, one image pick-up device  110   a  may be used for recording the images of the outside environment, while two image pick-up devices  110   b  and  110   c  may be used for recording the images of the rear seat(s) In addition, although the switching device  22  operates so as to switch between two image pick-up devices, the number of the image pick-up devices may be increased, for example the switching device  22  may switch four or eight image pick-up devices.  
      (Switching Operation, Zooming Operation, and Direction Changing Operation of Image Pick-Up Devices)  
      The operator may input instructions by means of the input device  134  of the control unit  130  in order to select the image pick-up device that is capturing the images inputted to the control unit  130 . In addition, the zooming angle and the orientation of the optical axis CZ 1  of each of the image-pick up devices  110   a  and  110   b  can be controlled.  
      As shown in  FIG. 11 (A), the first button group grp 1  buttons that are used for selecting from among the image pick-up devices  110   a  to  110   c  and for setting the direction of the optical axis CZ 1  and the zooming angle of the selected pick-up device(s) The first button group grp 1  further includes buttons that are used for selecting the image information (from among all of the image pick-up devices  110   a  to  110   c ) to be displayed on the display device  136 . For example, the display device  136  may singly display the information from the image pick-up device  110   a  or may simultaneously display all of the information from all of the image pick-up devices  110   a  to  110   c  on a single split screen. Each of the buttons on the operation panel  130 , including the first button group grp 1  and the second button group grp 2  may be designed for instructing plural types of functions. The instructions can be changed from one to another by a specific operation of the button. Preferably, the top surface of each button that an operator may touch with their fingers is coated with or made of a friction material, such as rubber, in order to prevent or minimize inadvertent operation due to slippage of the fingers.  
      By an input operation to the input device  134 , the operator can control a zooming device  111   a  of the image pick-up devices  110   a  or  110   b  via the CPU  131  and CPU  121 , in order to adjust the focal distance of the image pick-up devices  110   a  or  110   b . Similarly, by an input operation to the input device  134 , the operator can control a direction changing device  112   a  of the image pick-up device  110   a  or the image pick-up device  110   b  via the CPU  131  and the CPU  121 , in order to adjust the orientation of the image pick-up device  110   a  or  110   b  with respect to the horizontal plane and/or the vertical plane.  
      Further, by an input operation to the input device  134 , the operator can control the switching device  122  of the relay device  120  via the CPU  131  and the CPU  121 , in order to select between the image pick-up device  110   b  (for taking images of the outside environment to the rear of the patrol car S 1 ) and the image pick-up device  110   c  (for taking images within the interior of the patrol car S 1 ). In other words, it is possible to select which images are to be inputted to the control unit  130  from among the image information of the image pick-up device  110   b  and the image information of the image pick-up device  110   c.  In this representative embodiment, the image information captured by the image pick-up device  110   a  is directly inputted to the control unit  130  without intervention of a switching device.  
      In the same manner as in the second representative embodiment, each time that the compression device  123   a  receives the image information corresponding to one frame of the still images that are continuously captured by the image pick-up device  110   a  at predetermined time intervals (e.g., {fraction (1/60)} seconds), the compression device  123   a  compresses the received image information (i.e., the still image) and temporarily stores the compressed image information in the compression device  123   a . When the stored image information has reached a predetermined amount (such as a predetermined number of frames, e.g., five frames, of still images), the compression device  123   a  transmits the predetermined amount of stored image information to the CPU  131  of the control unit  130  as a batch of image signals. If the switching device  122  has been switched to transmit the image information from the image pick-up device  110   b  to the compression device  123   b , the compression device  123   b  compresses and stores the image information corresponding to one frame of the still images capture by the image pick-up device  110   b  each time that the compression device  123   b  receives image information corresponding to one frame. The compression device  123   b  transmits the stored information to the CPU  131  as a batch of image signals when the stored information has reached a predetermined amount, such as a predetermined number of frames, e.g., five frames, of the still images. If the switching device  122  has been switched to transmit the image information from the image take-up device  110   c  to the compression device  123   b , the compression device  123   b  compresses and stores the image information corresponding to one frame of the still images captured by the image pick-up device  110   c  each time that the compression device  123   b  receives the image information corresponding to one frame. The compression device  123   b  transmits the stored information to the CPU  131  as a batch of image signals when the stored information has reached a predetermined amount, such as a predetermined number of frames, e.g., five frames, of the still images.  
      If the compression devices  123   a  and  123   b  are configured as video image compression devices, the received image information may be compressed into compressed video image information, such as MPEG. If the compression devices  123   a  and  123   b  are configured as still image compression devices, the received information may be compressed into compressed still image information, such as JPEG. Alternatively, the compression devices  123   a  and  123   b  may be configured to serve as video image compression devices and also as still image compression devices. In such a case, the operator may select either the video image compression function or the still image compression function by an input operation to the input device  134 . Corresponding instructions may then be issued to the compression devices  123   a  and/or  123   b  via the CPU  131  and the CPU  121 .  
      (Change of Number of Frames Per Unit Time)  
      In this representative embodiment, the CPU  121  is configured to output synchronization signals to the image pick-up devices  110   a  to  110   c  via the corresponding compression devices  123   a  and  123   b . The output synchronization signals allow the time intervals of the output from the image pick-up devices  110   a  to  110   c  to be selectively determined. In addition, the cyclic period of the synchronization signals outputted from the CPU  121  may be directed from the CPU  131 . This allows the cyclic period to be set by the input operation of an operator to the input device  134 . Otherwise, the CPU  121  may automatically select the cyclic period based upon the detection signal from a sensor  140   b , such as a speed sensor of the patrol car S 1 . Each of the image pick-up devices  110   a  to  110   c  outputs an information signal, corresponding to one image frame, to the relay device  120  each time that the synchronization signal is received from the CPU  121  of the relay device  120 .  
      In the case where the sensor  140   b  is a speed sensor of the patrol car S 1 , the CPU  121  may change the cyclic period of the synchronization signals based upon the speed detected by the sensor  140   b . The number of frames per unit time to be captured by each of the image pick-up devices  110   a  to  110   c  can be increased or decreased. For example, if the detected speed is within a range of 0 to 10 km/h, a range of 10 to 20 km/h, a range of 20 to 30 km/h, a range of 30 to 40 km/h, a range of 40 to 50 km/h and more than 50 km/h, the number of frames per unit time may be respectively set to 10 frames/second, 20 frames/second, 30 frames/second, 40 frames/second, 50 frames/second, and 60 frames/second.  
      With this determination, the number of frames per unit time is relatively low during the slow speed traveling of the patrol car S 1 . Conversely, the number of frames per unit time is relatively large during the high speed traveling. Therefore, the quality (i.e., such as the amount of detail captured by each series of images) of the reproduced images can be maintained irrespective of change of the traveling speed. In addition, the capacity of the memory device  35  can be effectively utilized, because unnecessary or surplus image frames can be reduced.  
      (Storing of Image Information and Automatic Correction of the Internal Clock)  
      In this representative embodiment, the information inputted to the control unit  130  can be stored in the memory device  135 , mounted within the control unit  130 , based upon the input operation to the input device  134  for the control unit  130 .  
      Similar to the second representative embodiment, when the CPU  131  receives a batch of image signals from each of the compression devices  123   a  and  123   b , the CPU  131  affixes first information and second information to each image signal in such a manner that the first information and second information are included in the header of each image signal, as shown in FIGS.  12 (A) and  12 (C). The first information relates to the identification number to appropriately identify each of the image pick-up device  110   a ,  110   b , and  110   c.  The second information relates to the time when the image has been captured to allow for later identification of the capture time of the received information. The CPU  131  then transmits image information, which includes image signals each having the first and second information and any additional attribute information located in the header, to be temporarily stored in the buffer memory  133 .  
      The CPU  131  has a clock device or an internal clock (not shown) that enables the CPU  131  to recognize the current time. The CPU  131  also has a time matching device (not shown), so that the time indicated by the clock device can be corrected at predetermined time intervals. For example, the time matching device may utilize the time tone of a radio broadcast received by the radio receiver  137 . The time tone can be checked by accessing the radio receiver  137  at predetermined time intervals. Otherwise, the time matching device may receive current time information from a fixed station  150 , such as a police station, via the communication device  132 . For example, the communication device  132  may receive the current time information each time the driver starts the engine of the patrol car S 1 . It is also possible that the fixed station  150  transmits the current time information to positively correct the current time from the fixed station  150 .  
      In this representative embodiment, the CPU  131  may also add positional information to the header of the image signal as shown in  FIG. 12 (A). A simulated image on the display device  136  corresponding to  FIG. 12 (A) is shown in  FIG. 12 (B). Alternatively, the positional information together with the video capture time information may be stored in a file separate from the image information, as shown in  FIG. 12 (C). A simulated image on the display device  136  corresponding to  FIG. 12 (C) is shown in  FIG. 12 (D). The positional information can be obtained from the positional information acquisition device  140   a  (GPS). In the case that the positional information is stored in a separate file, new data (the positional information and the capture time information) may in turn be added at predetermined time intervals such as one minute.  
      In the case that the image information has been stored by a predetermined amount, the CPU  131  transfers the image information (including positional information stored in a separate file) in the buffer memory  133  to the memory device  135  when an instruction has been issued to store the information in the memory device  135 .  
      In this representative embodiment, the second button group grp 2  of the operation buttons (see  FIG. 11 (A)) includes a first sub-group of buttons and a second sub-group of buttons. The first sub-group includes buttons that are operated for instructing the selection of the desired image information from the image information obtained by the image pick-up devices  110   a ,  110   b,  and  110   c,  and for instructing the storing of the information in the memory device  135 . For example, when the operator pushes an operation button  130   a  (REC 1 ), the image information picked by the image pick-up device  10   a  may be stored or recorded in the memory device  135 . The second sub-group includes buttons that are operated for instructing the reproduction (i.e., playback) of the information stored in the memory device  135 . In addition to the buttons for manually storing the image information from the selected image pick-up device, an additional button may be provided for performing an automatic recording mode in order to automatically regularly store the image information that is inputted to the control unit  130 .  
       FIG. 11 (B) shows the second button group grp 2  extracted from the operation buttons of the operation panel  130   p  shown in  FIG. 11 (A). The arrangement of the operation buttons  130   a  to  130   h  of the second button group grp 2  is designed such that the operator (the driver or a passenger) can easily and readily record the images of the scene instantly upon based upon their judgment without incurring a high probability of making a substantial mistake in button operating.  
      In the arrangement shown in  FIG. 11 (B), the operation button  130   d  is operated for stopping the recording or reproducing process and is positioned substantially at the central position of the second button group grp 2 . The operation buttons  130   a  to  130   c  are positioned on the left-side of the operation button  130   d.  As previously described, the operation button  130   a  is pressed (or actuated) for the recording operation of the image information from the image pick-up device  110   a.  Similarly, the operation button  130   b  is pressed for the recording operation of the image information from the image pick-up device  110   b.  And finally, in this embodiment, the operation button  130   c  is pressed for starting the recording operation of the image information from the image pick-up device  110   c.    
      The operation buttons  130   e  to  130   h  are positioned to the right of the operation button  130   d  and are operated for various functions in connection with the reproduction (or playback) of the image information. More specifically, the operation buttons  130   e,    130   f,    130   g,  and  130   h,  are respectively operated for rewinding, playing, fast-forwarding, and pausing. Preferably, the operation button  130   d  is configured so as to enable the operator to easily distinguish the operation button  130   d  from the other buttons  130   a  to  130   c  when the operator touches the operation button  130   d.  For example, the operation button  130   d  may have different surface roughness, different surface irregularity, a different contour, or a different size than the other buttons. In this way, the operator can easily identify the position of the operation button  130   d.  The operator should then be able operate any of the operation buttons  130   a  to  130   h  without having to take their eyes off of the road.  
      Further, as described in connection with the second representative embodiment, even if it is not physically possible to write the information in the memory device  135 , for example due to excess vibrations of the patrol car S 1 , such information may be stored temporarily in the buffer memory  133  until the conditions of the memory device  133  have changed enough to allow the writing operation. In order to accomplish this function, a vibration sensor may be incorporated as a sensor  140   b . This is particularly applicable in a case where the buffer memory  133  is an IC memory and the memory device  135  is a HDD (Hard Disk Drive). Therefore, the image information and the positional information may be stored without omission even if vibrations have been produced during the traveling of the patrol car S 1 . In addition, it is possible to reduce or minimize problems associated with the memory device  135 . The capacity of the buffer memory  133  may be conveniently determined by taking into account the average length of time of potential vibration durations. The duration of vibrations, for example, may be the time period required for the patrol car S 1  to ride over railroad tracks or a possible stepped surface on the road.  
      For example, if the sensor  140   b  has detected a magnitude of vibration greater than a predetermined amount, the recording operation in the memory device  135  may be interrupted for a predetermined period while the recording operation in the buffer memory  133  is still performed without interruption. After expiration of the predetermined period and with a magnitude of vibration less than a predetermined amount, the image information stored in the buffer memory  133  may be transmitted so as to be stored in the memory device  135 .  
      As noted previously, the positional information acquisition device  140   a  may be a GPS that receives signals from an artificial satellite in order to identify the positional information (latitude and longitude) of the GPS itself. The GPS also may store the information corresponding to an address or map coordinates in relation to the current position. In this way, it is possible to identify the current position of the patrol car S 1  via the address or the map coordinates. In general, the GPS transmits the positional information identified by an address or map coordinates with regard to the current position to the CPU  121  of the relay device  120  at predetermined time intervals, such as one-minute intervals.  
      The CPU  121  can communicate with a personal computer  140   c  and the external memory device  140   d  via the communication device  124  in order to transmit or receive image information. Therefore, the image information can be stored in the personal computer  140   c  or the external memory device  140   d  via the communication device  124 . Preferably, the communication device  124  is a general-purpose interface designed to meet the USB (Universal Serial Bus) standard. Therefore, the communication device  124  may communicate with any from among various devices that have interfaces meeting the USB standard.  
      For example, if the relay device  120  is connected to the external memory device  140   d , the operator can select the image information that is desired to be stored in the external memory device  140   d . The desired information may be selected from the image information stored in the memory device  135 . The operator can then store the desired information in the external memory device  140   d  by means of the input device  134  and the display device  136  of the control unit  130 . In such a case, based upon the instructions issued from the input device  134 , the CPU  131  may transmit the desired information from the memory device  135  to the external memory device  140   d  via the CPU  121 .  
      Alternatively, if the relay device  120  is connected to a personal computer  140   c , the operator can select the image information that is desired to be stored in the personal computer  140   c  from among the image information stored in the memory device  135 . The operator can then store the desired information in the personal computer  140   c  by means of the input device (i.e., a keyboard) and the display device (i.e., a monitor) of the personal computer  140   c . In such a case, based upon instructions inputted from the personal computer  140   c  via the CPU  121 , the CPU  131  may transmit the desired information from the memory device  135  to the personal computer  140   c  via the CPU  121 .  
      The image information captured by the image pick-up devices  110   a  to  110   c  may be displayed on the display device  136  in real time. In addition, particular information from among the image information stored in the memory device  135  may be read by performing a search utilizing the identification number of the image pick-up device or the capture time as a search condition. The particular information may then be displayed on the display device  136 .  
      If a HDD is utilized as the memory device  135 , it is advantageous if the HDD has a self-diagnostic function utilizing a technology known as “Self-Monitoring Analysis and Reporting Technology (SMART).” For example, the memory device  135  may perform the self-diagnostic function each time the engine of the patrol car S 1  is started. The results of the self-diagnosis may then be displayed on the display device  136 . Therefore the operator can easily obtain confirmation as to the functioning status of the memory device  135 .  
      (Transmission of Image Information)  
      The operator can transmit the image information stored within the control unit  130  to the fixed station  150 , such as a police station, by inputting instructions into the input device  134  of the control unit  130 . As previously described, the image information may have an image signal along with the positional information included in the header (see FIGS.  12 (A) and  12 (B)) of the image signal. Alternatively, the positional information may be separated from the image information (see FIGS.  12 (C) and  12 (D)).  
      ((Transmission of Image Information When Positional Information is Included in Image Information))  
      If the positional information is included in the header of the image signal, as shown in FIGS.  12 (A) and  12 (B), the CPU  131  may transmit the image information (with the positional information in the header) in one file that is stored in the buffer memory  133 . The one file may be transmitted to the fixed station  150  via the communication device  132  and the antenna  138  in response to transmission instructions inputted to the input device  134 . In this way, a predetermined amount of the current image information may be transmitted to the fixed station  150 . The fixed station  150  may receive the transmitted information file via an antenna  158  and a transceiver  152 .  
      Therefore, the fixed station  150  can receive the image information (to-ether with the positional information, the capture time information, and any other information included in the header) that has been or is being captured in an emergency by the imaging system of the patrol car S 1 , under control of the fixed station  150 .  
      In other words, if an emergency situation occurs during a patrol by the patrol car S 1  while the patrol car S 1  is capturing images of the outside environment or the scene, the operator of the patrol car S 1  can immediately transmit the image information of the scene to the fixed station  150  by simply operating the corresponding operation button of the control unit  130 , such as the operation button  130   m  shown in  FIG. 11 (A).  
      In addition, a person at the fixed station  150  can readily visually recognize the situation of the scene in order to issue appropriate instructions to a person at the scene. In addition, the people at the fixed station  150  can immediately send necessary backup cars to the scene, because the pick-up position of the image can be readily recognized via the positional information included along with the image information. Since the image information and the positional information are transmitted in the same file, the image information and the positional information can be simply handled as information in one file. Therefore, the use of a single file facilitates the handling and management of the file. It can readily be known from the capture time information as to when the image was originally captured and in addition, it can readily be known from the identification number of the pick-up device as to which image pick-up device has been used for taking the image (see  FIG. 12 (A)).  
      ((Transmission of Image Information When Positional Information is Separated from the Corresponding Image Information))  
      If positional information is not included in the header of the image signal but instead is stored in a separate file, as shown in FIGS.  12 (C) and  12 ( 1 ), the CPU  131  may transmit separate files of the image information and the positional information, which are stored in the buffer memory  133 , to the fixed station  150  via the communication device  132  and the antenna  138 . The transmission of the separate files is in response to the transmission instructions inputted into the input device  134 . In this way, a predetermined amount of the current image information may be transmitted to the fixed station  150 . The fixed station  150  may receive the transmitted information files via the antenna  158  and the transceiver  152 .  
      Therefore, the fixed station  150  can receive the image information (together with the capture time information and any additional information included in the header), that has been or is currently captured and the positional information corresponding to the image information in an emergency situation, by the imaging system of the patrol car S 1 , under control of the fixed station  150 .  
      In the same manner as described in connection with the image information including the positional information in the header, the operator of the patrol car S 1  can immediately transmit the image information of the scene to the fixed station  150  by simply operating the corresponding operation button of the control unit  130 , such as the operation button  130   m  shown in  FIG. 11 (A). A person at the fixed station  150  can therefore readily visually recognize the situation at the scene.  
      (Displaying on Display Device and Selection of Image Information to be Recorded in Memory Device)  
      The operator can select the display mode of the display device  136  and can also select the image information or any additional information to be displayed on the display device  136  by inputting the appropriate instructions to the input device  134  of the control unit  130 .  
      For example, in an initial setting condition, the display device  136  may display only the image information captured by the image pick-up device  110   a  for recording the images of outside environment to the front of the patrol car S 1 . In such a case, the CPU  131  may direct the image information captured by the image pick-up device  110   a  and outputted from the compression device  123   a  to be displayed on the display device  136 .  
      The operator may operate the input device  134  or may input instructions into the input device  134  in order to display on the display device  136  the image information captured by the image pick-up device  110   b  or the image pick-up device  110   c . If the input device  134  is operated in order to display the image information captured by the image pick-up device  110   b,  the CPU  131  may operate the switching device  122  so as to select the image pick-up device  110   b  via the CPU  121 . The image information captured by the image pick-up device  110   b  may then be inputted into the display device  136 . Similarly, if the input device  134  is operated in order to display the image information captured by the image pick-up device  110   c , the CPU  131  may operate the switching device  122  to select the image pick-up device  110   c  via the CPU  121 . The image information captured by the image pick-up device  110   c  may then be inputted into the display device  136 .  
      In addition, the image information stored in the memory device  135  may be read and reproduced for displaying on the display device  136  by an input operation in to the input device  134 .  
      The image information captured by the image pick-up device  110   a  and outputted from the compression device  123   a  may be stored or recorded in the memory device  135  through an operation of the CPU  131  on the condition that the image information captured by the image pick-up device  110   a  is being displayed on the display device  136  when the operator operates the operation button  130   a  (REC 1 ) shown in FIGS.  11 (A) and  11 (B).  
      Similarly, the image information captured by the image pick-up device  110   b  and outputted from the compression device  123   b  may be stored or recorded in the memory device  135  on the condition that the image information obtained by the image pick-up device  110   b  is being displayed on the display device  136  when the operator operates the operation button  130   b  (REC 2 ) shown in FIGS.  11 (A) and  11 (B). The operator operates the operation button  130   b  in order to switch the switching device  122  to the image pick-up device  110   b  by an operation of the CPU  131  via the CPU  121 .  
      Further, the image information obtained (captured) by the image pick-up device  110   a  and outputted from the compression device  123   a  and the image information obtained by the image pick-up device  110   b  and outputted from the compression device  123   b  may be stored or recorded in the memory device  135  on the condition that image information captured by the image pick-up device  110   a  is being displayed on the display device  136  when the operator operates both the operation button  130   a  (REC 1 ) and the operation button  130   b  (REC 2 ), shown in FIGS.  11 (A) and  11 (B). The operator operates operation buttons,  130   a  and  130   b , in order to switch the switching device  122  to the image pick-up device  110   b  by an operation of the CPU  131  via the CPU  121 .  
      Similarly, when the operator operates both the operation button  130   a  (REC 1 ) and the operation button  130   c  (REC 3 ) shown in FIGS.  11 (A) and  11 (B) in order to switch the switching device  122  to the image pick-up device  110   c  by an operation of the CPU  131  via the CPU  121 , the image information obtained by the image pick-up device  110   a  and outputted from the compression device  123   a  and the image information obtained by the image pick-up device  110   c  and outputted from the compression device  123   b  may be stored or recorded in the memory device  135   
      In addition, it is possible to change the display mode of the display device  136  to a mode shown in  FIG. 13 (A), or to a mode shown in  FIG. 13 (B). In the mode shown in  FIG. 13 (A), the display is split uniformly into four regions  136   a  to  136   d . In the mode shown in  FIG. 13 (B), the display is non-uniformly split into four regions  136   a  to  136   d.    
      With the display modes shown in FIGS.  13 (A) and  13 (B), operation conditions of the imaging system, such as the operation details inputted by the operator and the process details executed based upon the inputted operation are also shown in the display region  136   d . Therefore, any mistake in operation and the possibility of overlooking a necessary operation can be reliably prevented.  
      Alternatively, as shown in  FIG. 13 (C), the operation conditions may be temporarily displayed in a particular region  136   e  within the display region  136   a  during a predetermined period of time, such as three seconds. In  FIG. 13 (C), the display region  136   a  occupies the entire display surface of the display device  136 . The display region  136   a  displays the image captured by the image pick-up device  110   a . A message is displayed in the region  136   e  to note that a radio broadcast is being received. For this case, it is possible to configure the system so that the displayed image information obtained by the image pick-up device  110   a  may be stored in the memory device  135  without storing the message information temporarily displayed within the region  136   e.    
      Further, it is not necessary to display the operation conditions on the display device  136  in order to indicate the operation conditions to the operator. For example, an LED may be mounted to each operation button. The operated button can be illuminated or flashed in order to distinguish the operated button from the other buttons. More specifically, in the state where no button is operated, all the LEDs associated with the buttons may be lit. When the operator pushes any of the buttons, such as the operation button  130   a  (REC 1 ), the LED associated with the pushed button may remain illuminated or flashing, while the LEDs associated with the other buttons may be switched off for a predetermined time period. After the predetermined time period has elapsed, all of the LEDs may be illuminated again. In this way, it is possible to reliably visually recognize the pushed button(s).  
      Furthermore, as shown in  FIG. 10 , a display device  136 A and a display device  136 B may be respectively connected to the relay device  120  and the control unit  130 . Alternatively, only one of the display devices  136 A and the display device  136 H may be provided. The display device  136 A and/or the display device  136 B may be positioned at a suitable position, such as a position proximate to the rear seat(s), so that a passenger can see the displayed image on the display device  136 A or  136 B even if they cannot see the displayed image on the display device  136  of the control unit  130 .  
      By connecting the display device  136 B to the relay device  120 , the CPU  121  may output signals to the CPU  131  instructing the CPU  131  to obtain the image information. The CPU  131  then transmits the image information that is outputted to the display device  136  to the CPU  121 . The CPU  121  outputs the image information to the display device  136 B.  
      (Indication of Remaining Storage Capacity of Memory Device)  
      The CPU  131  may be operable to detect the remaining capacity of the memory device  135 . In addition, the CPU  131  may then transmit information regarding the remaining capacity to the display device  136 . For example, such information may include the number of bytes of the remaining capacity, the remaining time available for storing, and an anticipated period for exchange.  
      The time for displaying the information with regard to the remaining capacity may preferably be set to the time when the engine of the patrol car S 1  is started. To achieve this function, it is further preferable that the CPU  131  automatically detects the remaining capacity of the memory device  135  for displaying on the display device  136  in response to the starting of the engine.  
      Further, it is preferable that the display device  136  or the speaker  140   f  outputs an alert if the remaining capacity of the memory device  135  is less than a predetermined level, or if the memory device  135  is not connected to the control unit  130  when the engine of the patrol car S 1  is started. Consequently, it is possible to reliably prevent a situation in which the image information cannot be stored when the operator operates the imaging system so as to record the image information, after the patrol car S 1  has reached a target location.  
      (Mounting and Exchanging of Memory Device)  
      The operation for mounting and exchanging the memory device  135  will now be described with reference to  FIG. 11 (C).  FIG. 11 (C) shows the configuration where the operation panel  130   p  of the control unit  130  has been tilted opened to the side of the operator (i.e., in a direction extending perpendicular to the sheet of  FIG. 11 (C)). Alternatively, the control unit  130  may be designed such that the operation panel  130   p  is opened to the left, the right, or the direction opposite to the direction shown, of the control unit  130 .  
      The operator may open and close the operation panel  130  by a predetermined operation. The operator can remove the memory device  135  (not shown in  FIG. 11 (C)) from the control unit  130  via an access opening  130 H by pushing an operation button  130 T when the operation panel  130   p  is opened. A connector (not shown) is disposed on the backside of the access opening  130 H in order to connect to the memory device  135 . When the operator inserts the memory device  135  into the access opening  130 H and Connects the memory device  135  to the connector, the connector automatically moves to a predetermined position within the control unit  130 . Therefore the memory device  135  can be suitably positioned within the control unit  130 .  
      The capacity of the memory device  135  may be appropriately chosen from various amounts of memory, for example, some common current memory amounts are 20 GB, 30 GB, and 40 GE.  
      In addition, it is preferable that only authorized people are able to make changes to the memory device  135  (i.e., replacement, etc.). In order to restrict access to the memory device  135 , the control unit  130  may be designed such that the operation panel  130   p  is only opened when a predetermined password has been inputted via suitable operations buttons provided on the operation panel  130   p.  Alternatively, a specific operation button may be provided that functions to enable the other operation buttons to be used for various control operations in order to serve as password input buttons. For example, by operating the specific operation button, the operation button  130   b  may be used for inputting the numeral “1” or alphabetic characters such as “A,” “B,” and “C.” 
      (Central Control of Power Source)  
      The relay device  120  may have a power source  125  that is connected to a battery  140   e  of the patrol car S 1 . The power supplied to the power source  125  from the battery  140   e  may be used for operating the relay device  120 , the control unit  130  including the memory device  135 , and the image pick-up devices  110   a  to  110   c , etc. In other words, the power source  125  serves as a common power source for the various electric devices of the imaging system. Therefore, it is possible to reliably prevent accidental interruptions of the power supply to any of the electric devices. Such accidental interruption may be caused in some cases depending on the condition of the patrol car S. In addition it is also possible to reliably prevent unstable operation of the imaging system due to the potential delay of start-up or shut-down operations of different power sources.  
      (Wireless Communication)  
      In the case where the patrol car S 1  is a police car, the fixed station  150  may be a police station of a particular district. In such a situation, the communication device  132  of the control unit  132  may be a wireless receiver and transmitter for police radio communication. For example, the microphone  140   z  shown in  FIG. 8  may be used for police radio communication. The communication device  132  can transmit voice information to the transceiver  152  of the fixed station  150  and receive voice information from the transceiver  152  via a police wireless communication line. In addition, if the operation for “transmission of image information” described previously has been made, the communication device  132  may transmit the image information to the transceiver  152  of the fixed station  150  via the police wireless communication line.  
      In addition, the operator can transmit voice information from the microphone  140   z  to a portable transceiver carried by a person, such as a policeman, via the relay device  120  and the control unit  130  (in particular, the communication device  132  of the control unit  130 ). The voice information that has been transmitted from the communication device  132  to the transceiver  152  of the fixed station  150  or the portable transceiver and the voice information that has been received by the communication device  132  from the transceiver  152  or the portable transceiver may be stored in the memory device  135  by the operation of the control unit  130 , such as the operation of the related operation button. Similarly, the voice information inputted to the microphone  140   z  by the operator can also be stored in the memory device  135 .  
      In this way, wireless voice communication information between the microphone  140   z  and the transceiver  152  of the fixed station  150  or the portable transceiver, can be stored in the memory device  135  by the operator of the patrol car S 1 . Conveniently, the system may be configured such that it is possible to store only the voice information inputted to the microphone  140   z,  so that the operator can record voice information in the form of daily report data or the like.  
      (Record of Passenger)  
      Since many people may use the patrol car S 1 , it is preferable to record information concerning the identities of people who use the patrol car S 1  and information regarding the time when the people use the patrol car S 1 . Therefore, each person who uses the patrol car S 1  may preferably carry an IC tag. The IC tag may be a wireless tag of a non-contact type and may store identification information of the person who carries the IC tag. In connection with the IC tags, a reader for reading the identification information may be mounted to the control unit  130  or the relay device  120 .  
      For example, the control unit  130  may read the identification information of the person riding in the patrol car S 1  at predetermined time intervals, such as five-minute intervals. The control unit  130  may then store the read information in the memory device  135  together with the time that the reading operation was performed. Based upon the stored identification information and the reading time information, it is possible to easily extract information with regard to the particular occupants of the patrol car S 1  and the time that they were in the vehicle from the stored information. The time information may not be necessary if the memory device  135  is exchanged for another memory device every time or at each time a new patrol is undertaken.  
      Further, it is possible to reference the identification information prior to the starting of the engine of the patrol car S 1 . In connection with this situation, information indicating the correlation between each piece of identification information and each person may be stored in the control unit  130 , the relay device  120 , or the fixed station  150 . For example, the control unit  130  may read the identification information before starting the engine by means of a suitable reading device. In the case where the correlation information is stored in the control unit  130 , the control unit  130  may directly refer to the correlation information in order to compare the identification information with the correlation information.  
      In the case where the correlation information is stored in the relay device  120 , the identification information read by the control unit  130  may be transmitted to the relay device  120 . The comparison may then be made at the relay device  120 . Subsequently, the result of comparison may be transmitted to the control unit  130 .  
      In the case that the correlation information is stored at the fixed station  150 , the identification information read by the control unit  130  may be transmitted to the transceiver  152  of the fixed station  150 . The comparison may then be made at the fixed station  150 . Subsequently, the result of comparison may be transmitted to the control unit  130 .