JP2011150417A - In-vehicle electronic apparatus and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an in-vehicle electronic apparatus comparatively certainly performing control based on an inter-vehicle distance even if a camera is an inexpensive one. <P>SOLUTION: A license plate has a different aspect ratio and a size by the kind (large size/medium size/small size) of a vehicle installed therewith. When photographing the license plate, the license plate is larger in picture as a distance to the license plate is closer when the license plate has the same size. Therefore, a control part obtains the size and the aspect ratio of the license plate from video data received from the vehicle outside photographic camera when the license plate is present in the video data, reads, from a database, a relation with a distance to the vehicle having the license plate from an own vehicle corresponding to the aspect ratio and the size, obtains the inter-vehicle distance to the vehicle having the license plate from the own vehicle based thereon, and displays the inter-vehicle distance on an inter-vehicle distance display part. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an in-vehicle electronic device that performs control based on a distance between vehicles.

  Patent Document 1 discloses an inter-vehicle distance detection device that recognizes the size of a character on a license plate with an image capturing camera that captures and recognizes the license plate and derives the inter-vehicle distance based on the size of the character. Yes. In this document, it is shown that the inter-vehicle distance is derived in consideration of the lateral size of the license plate.

JP 2004-271250 A

  However, in order to recognize the characters on the license plate, there is a problem that a high-resolution camera is required and the processing device for character recognition is expensive. In addition, there is a problem that it is difficult to reliably perform character recognition. Further, there is a problem that it is difficult to calculate a certain distance only based on the lateral size of the license plate.

  Accordingly, the present invention has been made to solve such a problem, and an object thereof is to provide an in-vehicle electronic device capable of relatively reliably performing control based on the inter-vehicle distance even with an inexpensive camera. And

  In order to achieve the above-described object, an in-vehicle electronic device according to the present invention includes (1) a photographing unit that photographs the front of the host vehicle, a size of a license plate in an image photographed by the photographing unit, There is a license plate in the storage means for storing the relationship between the distance from the vehicle to the vehicle having the license plate for each aspect ratio of the license plate and the image in front of the host vehicle photographed by the photographing means. In this case, a control means for obtaining a size and an aspect ratio of the license plate, obtaining a distance from the host vehicle corresponding to the aspect ratio and the size to the vehicle having the license plate, and performing control based on the distance. It is characterized by providing.

  There are several license plates with different aspect ratios. And, license plates having different aspect ratios have different sizes, and license plates having the same aspect ratio have the same size. Then, the size of the license plate taken and captured in the image data has a relative difference depending on the distance to the license plate (the closer it is, the larger it is). Therefore, the size can be specified based on the aspect ratio of the license plate, and the vehicle having the number plate from the own vehicle based on the relationship of the distance from the own vehicle stored for each size to the vehicle having the number plate. The distance to is obtained and control based on the distance is performed.

  In this way, without recognizing the size of the letters on the license plate, the distance from the host vehicle to the vehicle having the license plate can be determined relatively reliably, and control based on that distance can be performed. . Since license plates having different aspect ratios / sizes are distributed according to the type of vehicle, the type of vehicle can be specified based on the aspect ratio of the license plate.

  (2) The storage means stores the relationship between the size of the license plate and the distance from the host vehicle to the vehicle having the license plate for each of a plurality of distances, and the control means takes a picture with the photographing means. The distance may be calculated by comparing the size of the license plate in the image ahead of the host vehicle and the size of the license plate stored in the storage means.

  In this way, a more reliable distance can be calculated. For example, even if the size varies depending on the distance due to the optical system such as a lens or the characteristics of the image sensor, the distance error is calculated by storing the distance for each distance and calculating the distance compared to these distances. Can be reduced.

  (3) The aspect ratio of the license plate stored in the storage means may include three types of large, medium, and small.

(4) The storage means, for each of a plurality of attachment positions, the relationship between the size of the license plate in the video imaged by the imaging means and the distance from the host vehicle to the vehicle having the license plate, Stored for each aspect ratio of the license plate, the control means includes setting means for setting the mounting position of the imaging means, and based on the relationship stored in the storage means of the mounting position set in the setting means The distance may be obtained.
In this way, the error in distance due to the installation position can be reduced, and more reliable control can be performed.

(5) The control unit includes a setting unit that sets an attachment position of the imaging unit, and corrects the distance in consideration of a correction amount of the distance stored for each attachment position of the imaging unit. Also good.
In this way, the error in distance due to the installation position can be reduced, and more reliable control can be performed.

  (6) On the premise of the configuration of (4) or (5), the attachment position may include a vicinity of the front end of the vehicle and a vicinity of the front end of the vehicle. In this way, the error in the distance between the vicinity of the front end of the vehicle and the vicinity of the front end in the vehicle can be reduced, and more reliable control can be performed.

  (7) It is good to have composition which provides a reporting means, and the control means performs control which reports from the reporting means when the distance becomes below a preset distance. For example, the control unit may notify the alarm by sound or light from the notification unit when the distance is equal to or less than a preset distance.

  In this way, for example, the driver can know that the inter-vehicle distance with the vehicle ahead is less than the set distance, avoiding rear-end collisions, or avoiding clearance and accidents in advance due to non-inter-vehicle distance retention. be able to.

  (8) The said control means is good to set it as the structure which makes the content of the control based on the said distance differ according to the aspect ratio of the calculated | required license plate. If it does in this way, different control can be performed for every vehicles from which the aspect ratio of a license plate differs, for example, such as a large-sized car, a medium-sized car, and a small car.

  (9) The functions of the on-vehicle electronic device according to any one of (1) to (8) can be realized as a program for causing a computer to realize the function.

  ADVANTAGE OF THE INVENTION According to this invention, the vehicle-mounted electronic device which can perform alerting | reporting to call attention when approaching the vehicle which requires attention can be provided.

It is a figure which shows the structure of the radar detector which is preferable one Embodiment of this invention. It is a block diagram of a radar detector. It is a figure which shows the example of a display of a standby screen, a radar scope, and a GPS alarm. It is a figure which shows the example of a display of a radar wave warning. It is a figure which shows the size and aspect ratio of a license plate. It is a figure which shows the attachment position of a camera.

  1 and 2 show a configuration of a radar detector which is a preferred embodiment as an in-vehicle electronic device of the present invention. The radar detector is usually mounted on the dashboard. As shown in FIG. 1, this radar detector has a solar panel 2 and a switch unit 3 arranged on the upper surface of the case body 1, and the front side of the case body 1 (the side arranged on the front side of the vehicle (the windshield side)). Are equipped with an infrared projector 21 for irradiating the front of the vehicle with infrared rays and an outside-vehicle camera 23 for shooting the front of the vehicle, and a microwave for detecting microwaves in a frequency band emitted by the speed measuring device inside the front side. A wave receiver 4 is arranged. On the other hand, a display unit 5, an alarm lamp 6, an infrared communication device 7, and a remote control receiver 16 are arranged on the rear side of the case body 1 (the side arranged on the rear side of the vehicle (user side (driver side)). A GPS receiver 8 is disposed inside the upper surface of the case body 1. Further, an adapter jack 9 is disposed on one side surface of the case body 1, and a power switch 10 and an illustration are omitted on the other side surface. In addition, a speaker 20 is also built in the case body 1. In the present embodiment, the display unit 5 is a 2.4-inch small liquid crystal display, and the rear side of the case body 1 (The rear side of the vehicle (user side (driver side)) is used as a display surface. The height H on the rear side of the case body 1 on which the display unit 5 is mounted is larger than the height H0 of other parts. is doing

  A column 31 is provided at the center of the bottom surface of the case body 1 so as to stand downward. The lower end of the column 31 has a ball structure, and is fitted with the ball receiving structure on the upper surface of the column receiving part 33a of the pedestal 33 to constitute a ball joint structure. This ball joint structure is configured so that the ball receiving structure tightens the ball structure by making the outer diameter of the ball structure and the inner diameter of the ball receiving structure substantially coincide or the inner diameter of the ball receiving structure is slightly smaller than the outer diameter of the ball structure. Therefore, both states are fixed at a desired position. The pedestal 33 includes a plate-like fixing portion 33b that is integrally formed with the column receiving portion 33a. The bottom surface of the fixing portion 33b is fixed on the dashboard with an adhesive mat made of double-sided tape, gel material, or the like. When the radar detector is fixed to the dashboard of the vehicle by the fixing unit 33, the outside-camera shooting camera 23 is arranged in a direction and a position where the license plate of another vehicle can be imaged. On the other hand, the display surface of the display unit 5 is arranged so that the driver of the host vehicle can recognize the display content when the radar detector is fixed to the dashboard of the vehicle by the fixing unit 33. In the present embodiment, the display unit 5 is arranged on the driver side, the outside-camera shooting camera 23 is arranged on the front side, the normal vector of the display surface of the display unit 5 and the shooting direction vector (CCD) of the outside-camera shooting camera 23. The normal vector of the imaging surface of the camera is arranged in the opposite direction. With this configuration, the fixing portion 33 is fixed with an adhesive mat or the like made of double-sided tape or gel material with the display surface of the display portion 5 facing the position where the driver of the vehicle can recognize the contents of the notification. In this case, the outside-camera camera 23 faces in the direction in which the license plate of the other vehicle in front of the vehicle can be imaged. Therefore, when the radar detector is fixed, the radar detector can be easily installed without being aware of the direction of the imaging unit, and the size and aspect ratio of the license plate can be reliably acquired.

  As shown in FIG. 2, the infrared communication device 7 transmits and receives data to and from a communication device incorporating an infrared communication device such as a mobile phone 12. The adapter jack 9 is a terminal for connecting the memory card reader 13. By connecting the memory card reader 13 to the adapter jack 9, the data stored in the memory card 14 attached to the memory card reader 13 can be taken in, or the contents of the memory of the database 19 and the control unit 18 can be transferred to the memory card. 14 can be written. More specifically, when the data stored in the memory card 14 includes update information such as new target information (position information including longitude and latitude, type information, etc.), the update information is sent to the control unit 18. Is stored (downloaded) in the database 19 built in the apparatus, and the data in the database 19 is updated. The function of the memory card reader 13 may be configured to be built in the main body case 1.

  The database 19 is a nonvolatile memory (for example, EEPROM) in the microcomputer of the control unit 18 or externally attached to the microcomputer. The database 19 stores information on a certain target at the time of shipment, and the relationship between the number of the vehicle license plate and the distance from the host vehicle to the vehicle having the license plate for each aspect ratio of the license plate. The data added / changed thereafter can be updated as described above. Data update can also be performed via the infrared communication device 7.

  The DC jack is for connecting a cigar plug cord (not shown), and is connected to a cigar socket of the vehicle via the cigar plug cord so that power can be supplied. The wireless receiver 15 receives incoming radio waves having a predetermined frequency. The remote control receiver 16 performs data communication with a remote control (portable device: handset) 17 by infrared rays and performs various settings for the device. The switch unit 3 is also connected to the control unit 18 (not shown) so that the same setting as the remote controller 17 can be performed. The remote controller 17 includes a play button, a standby switching button, a setting button, a selection button, a cancel button, an enter button, and up / down / left / right cross buttons.

  The control unit 18 is a microcomputer including a CPU, a ROM, a RAM, a nonvolatile memory, an I / O, and the like. The control unit 18 executes predetermined processing based on information input from the above various input devices, and outputs an output device. Use it to output predetermined alarms, messages and information. Note that these basic configurations can be basically the same as the conventional ones.

  The functions of the radar detector of the present embodiment are realized by being stored on the EEPROM of the control unit 18 as a program executed by the computer included in the control unit 18 and executed by the computer included in the control unit 18.

  Functions realized by the computer by the program of the control unit 18 include a GPS log function, a video display function, a video recording function, a video playback function, a standby screen display function, a radar scope display function, a GPS alarm function, a radar wave alarm function, There is a wireless alarm function.

  The GPS log function is a function in which the control unit 18 stores the current position detected by the GPS receiver 8 every second in association with the detected time and speed (vehicle speed) in the nonvolatile memory as a position history. This position history is a function of recording in the NMEA format, for example.

  The video display function is a function for causing the display unit 5 to display video data received from the outside-camera shooting camera 23 when the control unit 18 detects pressing of a video display button provided on the remote controller 17. The video recording function compresses video data received from the outside camera 23 into a non-volatile memory externally attached to the microcomputer of the control unit 18 when the control unit 18 detects that the video display button provided on the remote controller 17 is pressed. It is a function to record. When the control unit 18 detects that the video display button provided on the remote controller 17 has been pressed, the video playback function decompresses the video data compressed and recorded in a nonvolatile memory externally attached to the microcomputer, and displays it on the display unit 5. It is a function to display.

The outside-camera shooting camera 23 is a CCD camera capable of shooting in the visible and infrared bands, and is internally connected to a USB port provided in the microcomputer of the control unit 18. The outside camera 23 has a function of A / D converting an image captured by the CCD camera and sending it to the control unit 18 as image data. This function has the same configuration as a so-called USB camera. The control unit 18 determines whether or not the illuminance necessary for detecting the size of the license plate of the vehicle ahead is insufficient from the brightness of the video data of the video captured by the CCD camera, and when the illuminance is insufficient Turns on the infrared projector 21 and irradiates the front of the vehicle with infrared rays.
The standby screen display function is a function for displaying the distance, latitude, longitude, and altitude between the host vehicle and the preceding vehicle detected by the GPS receiver 8 on the display unit 5 as shown in FIG.

  As shown in FIG. 3 (b), the radar scope display function is a position where a target within a predetermined range (for example, within a range of about 1 km) from the current position detected by the GPS receiver 8 is stored in the database 19. This is a function of searching based on information and displaying the relative positional relationship between the vehicle position and the position of the target on the display unit 5. In FIG. 3B, “W” on the left side indicates the west, “E” on the right side indicates the east, and “N” on the upper side indicates the north direction, and the horizontal line connecting “W” and “E” and “N” The icon at the intersection of the vertical line extending downward from "" indicates the vehicle position. Icons having characters such as “L”, “RD”, “P”, and “N” indicate the type and position of the target.

  When pressing of a standby switching button provided on the remote controller 17 is detected during execution of the standby screen display function as shown in FIG. 3A, the radar scope display function is switched to as shown in FIG. Further, when pressing of a standby switching button provided on the remote controller 17 is detected during execution of the radar scope display function, the display is switched to the video display function. Further, when pressing of a standby switch button provided on the remote controller 17 is detected during execution of the video display function, processing for switching to the standby screen display function is performed.

  The control unit 18 performs a GPS alarm function, a radar according to an event that occurs during execution of a video display function, a standby screen display function, or a radar scope display function (hereinafter, these functions are collectively referred to as a standby function). The processing for realizing each function such as a wave alarm function and a radio alarm function is executed. The priority of each function is set in the order of radar wave warning function, radio alarm function, and GPS alarm function from the highest.

  The GPS alarm function is a process executed at a predetermined time interval (1 second interval) by an event from a timer included in the control unit 18 and detected by the latitude and longitude of the target stored in the database 19 and the GPS receiver 8. The distance between the current position is obtained from the latitude and longitude of the current position, and when the obtained distance reaches a predetermined approach distance (for example, within 500 m), that fact is displayed on the display unit 5 and an approach warning indicating that fact from the speaker 20. This is a process for outputting the voice.

  Such targets include snoozing driving accident points, radar, speed limit switching points, control areas, inspection areas, parking monitoring areas, N systems, traffic monitoring systems, intersection monitoring points, signal ignorance suppression systems, police stations, frequent accidents Area, frequent on-board areas, sudden / continuous curve (highway), branch / merge point (highway), ETC lane advance guidance (highway), service area (highway), parking area (highway), highway Oasis (highway), smart interchange (highway), PA / SA petrol station (highway), tunnel (highway), highway radio reception area (highway), prefectural border notice, roadside station, viewpoint parking, etc. The type information of these targets, the latitude / longitude information indicating the position, and the display unit 5 Stored in the database 19 in association with the formulas drawings or photos and audio data.

  The radar wave warning function is used when the microwave receiver 4 detects a signal corresponding to a microwave in a frequency band emitted from a velocity measuring device (mobile radar or the like (hereinafter simply referred to as “radar”)). This is an alarm function for displaying an alarm screen on the display unit 5 and outputting an alarm sound from the speaker 20. For example, when a microwave in a microwave frequency band emitted by a radar is detected by the microwave receiver 4, as shown in FIG. 4, a schematic diagram or a photograph of the radar stored in the database 19 is displayed on the display unit 5. While being displayed as an alarm screen, the voice data stored in the database 19 is read out and a voice “Radar. Speed attention” is output from the speaker 20. During sound output, the alarm lamp 6 is turned on.

  The wireless alarm function is a function for issuing an alarm so that the wireless receiver 15 does not interfere with traveling or the like when a radio wave emitted by an emergency vehicle or the like is received. In the radio alarm function, the control radio, car radio, digital radio, special radio, police radio, police phone, police activity radio, wrecker radio, heli tele radio, fire helicopter radio, fire fight radio, emergency radio, expressway radio , Scan the frequency of the security radio, etc., and when the radio is received at the scanned frequency, a schematic diagram showing that the radio corresponding to the frequency stored in the database 19 for each radio type is received as an alarm screen While displaying on the display part 5, the audio | voice data memorize | stored for every radio | wireless classification in the database 19 are read, and the alarm sound which shows the radio | wireless classification from the speaker 20 is output. For example, when a control radio is received, a voice is output like “control radio. Speed attention”. During sound output, the alarm lamp 6 is turned on.

  As shown in FIGS. 3A and 3B, an inter-vehicle distance display unit 51 is provided in the display screen in the standby screen display function and the radar scope display function, and a predetermined time interval (for example, 1 second) is provided. Updates and displays the value of the distance between vehicles. This function is called an inter-vehicle distance display function.

  When the license plate is present in the video data from the video data received from the outside camera 23, the control unit 18 obtains the size and aspect ratio of the license plate. The relationship between the vehicle from the own vehicle corresponding to the ratio and the size to the vehicle having the license plate is read from the database 19, and based on this, the distance from the own vehicle to the vehicle having the license plate is obtained, and the distance is This function is displayed on the distance display unit 51.

  The size (size) of the license plate is defined as shown in FIG. 5 except for some special vehicles (SDF etc.). As shown in FIG. 5, the large number mark is 220 mm long × 440 mm wide, the aspect ratio (horizontal / vertical) is 2, the medium number mark is 165 mm long × 320 mm wide, the aspect ratio (horizontal / vertical) is 1.94, and small. The number mark is 125 mm long × 230 mm wide and the aspect ratio (horizontal / vertical) is 1.84.

  As described above, the database 19 stores the relationship between the license plate size of the vehicle and the distance from the host vehicle to the vehicle having the license plate for each aspect ratio of the license plate. Because there is a difference in the relative size of the license plate, the relative number of the license plate at the distance L1, L2,..., Ln is obtained from image data obtained by attaching a camera equivalent to the outside camera 23 to the front end of the vehicle. A typical size (number of vertical and horizontal dots in the image data) is stored in the database 19. For example, the relative sizes of the license plates L1 to L100 are stored at 1 m intervals from 1 m to 100 m.

  The inter-vehicle distance L is obtained by comparing the relative size stored in the database 19 with the relative size of the license plate of the vehicle traveling ahead obtained from the outside camera 23.

  There are differences in the number of license plates, as shown in FIG. 5, depending on the vehicle (large, medium, and small). Accordingly, the database 19 stores these data for each vehicle type. The control unit 18 identifies the vehicle from the aspect ratio (horizontal / vertical) of the license plate from the image data, reads the data from the database 19 and obtains the inter-vehicle distance L. As in this embodiment, when the outside camera 23 is mounted inside the vehicle, a correction function is provided to correct the standard distance L0 from the vehicle front end to the vehicle front end by subtracting from the inter-vehicle distance L. ing. Then, the inter-vehicle distance (L-L0) corrected by the correction function is displayed on the inter-vehicle distance display unit 51. L0 is, for example, 1 m. For example, the inter-vehicle distance corresponding to L3 in FIG. 6 is obtained by comparing the relative size of the license plate of the vehicle traveling ahead acquired from the outside camera 23 and the relative size stored in the database 19. In this case, the inter-vehicle distance corrected by the correction function is L3-L0, and the corrected inter-vehicle distance is displayed on the inter-vehicle distance display unit 51.

  By configuring in this way, the distance from the host vehicle to the vehicle having the license plate can be determined relatively reliably even with an inexpensive camera without recognizing the size of the characters on the license plate, and the distance is displayed. Can be made.

  The database 19 stores the relationship between the number of the license plate and the distance from the host vehicle to the vehicle having the license plate for each of a plurality of distances. Since the configuration is such that the distance between the license plates in the video ahead of the host vehicle is compared with the number of the license plates stored in the database 19, the inter-vehicle distance is calculated, so that a reliable distance can be calculated. For example, even when the size varies depending on the distance due to the optical system such as the lens of the camera 23 outside the vehicle and the characteristics of the image sensor, the distance is stored for each of the plurality of distances L1 to Ln and compared with these distances. Therefore, the distance error can be reduced.

  In this embodiment, the outside-camera camera 23 is built in the radar detector. However, the camera 23 may be externally connected by a cable or the like instead of being built in the radar detector. In the case of an external configuration, the database 19 includes, in each of the plurality of attachment positions, the size of the license plate in the video photographed by the outside camera 23 and the distance from the host vehicle to the vehicle having the license plate. Is stored for each aspect ratio of the license plate, and when the control unit 18 detects that the setting button of the remote controller 17 is pressed, the control unit 18 displays a list of the plurality of attachment positions on the display unit 5, and It is preferable to provide a setting function for detecting the pressing of the up / down button 17 and the confirm button 17 and selecting and setting (stored in the database 19) the actual mounting position of the outside-camera shooting camera 23 from the list display. When the control unit 18 obtains the distance to be displayed on the inter-vehicle distance display unit 51, the license plate of the number plate in the video photographed by the outside-camera shooting camera 23 stored in the database 19 of the mounting position set by this setting function. The distance may be determined based on the relationship between the size and the distance from the host vehicle to the vehicle having the license plate. In this way, the distance error due to the installation position can be reduced, and more reliable control is possible. It can be performed.

  In addition, the database 19 shows the relationship between the number of the license plate in the video photographed by the outside camera 23 and the distance from the own vehicle to the vehicle having the license plate for each of a plurality of mounting positions. Instead of storing each aspect ratio, the control unit 18 considers the inter-vehicle distance displayed on the inter-vehicle distance display unit 51 in consideration of the correction amount of the inter-vehicle distance stored in the database 19 for each attachment position of the outside-camera camera 23. Alternatively, the correction may be made.

  In addition, the database 19 shows the relationship between the number of the license plate in the video photographed by the outside camera 23 and the distance from the own vehicle to the vehicle having the license plate for each of a plurality of mounting positions. While storing for each aspect ratio, the control unit 18 corrects the inter-vehicle distance displayed on the inter-vehicle distance display unit 51 in consideration of the correction amount of the inter-vehicle distance stored in the database 19 for each mounting position of the outside camera 23. It is good also as composition to do.

  In this way, the error in distance due to the installation position can be reduced, and more reliable control can be performed. This attachment position may be configured to include the vicinity of the front end of the vehicle and the vicinity of the front end of the vehicle. In this way, the error in the distance between the vicinity of the front end of the vehicle and the vicinity of the front end in the vehicle can be reduced, and more reliable control can be performed.

  In the present embodiment, the value of the inter-vehicle distance from the preceding vehicle is displayed as the control based on the distance. However, the control unit 18 displays when the calculated inter-vehicle distance is equal to or less than a preset distance (for example, 30 m). You may make it alert | report an alarm, for example by displaying on the part 5 "attention to the distance between vehicles!". In addition to this display, the control unit 18 may perform control to output an alarm sound or a warning by sound from the speaker 20. In this way, the driver can know that the distance between the vehicle and the vehicle ahead is less than the set distance, avoiding rear-end collisions, etc., and avoiding clearance and accidents in advance due to inability to maintain the distance between vehicles. it can.

  Moreover, the control part 18 is good also as what changes the content of control according to the aspect ratio of the calculated | required license plate. For example, when the aspect ratio of the large number mark is detected, the display “Warning about the front car!” May be performed instead of the above-mentioned display “Warning about the distance between vehicles!”. In addition, for example, if a large vehicle is too close, the front signal may be shadowed by the large vehicle and become invisible, and it is necessary to make the inter-vehicle distance larger than that of a medium or small vehicle. When the ratio is detected, for example, when the calculated inter-vehicle distance is 20 m or less, the display unit 5 displays "Warning about inter-vehicle distance!" May be displayed on the display unit 5 when the calculated inter-vehicle distance is 10 m or less.

  In this embodiment, the radar detector has been described as an example. However, the present invention can be implemented as a function of various on-vehicle electronic devices. For example, you may incorporate as a function of a navigation apparatus, a drive recorder, and a car audio. In addition, the numerical values described in the present embodiment may be appropriately changed to values that exhibit an effect through experiments and the like. In addition, the functions described in this embodiment can be combined as appropriate.

  For example, when realized as a drive recorder, the camera corresponding to the outside-camera shooting camera 23 may be attached to the top of the windshield near the front end of the vehicle. The camera may be housed in a rearview mirror near the front end of the vehicle or attached to the back of the rearview mirror.

DESCRIPTION OF SYMBOLS 1 Case main body 2 Solar panel 4 Microwave receiver 5 Display part 6 Lamp 7 Infrared communication device 8 GPS receiver 9 Adapter jack 10 Power switch 11 Mobile phone 12 Memory card reader 14 Memory card 15 Wireless receiver 16 Remote control receiver 17 Remote control 18 Control Unit 19 Database 20 Speaker 21 Infrared Projector 23 Outside Camera 51 Vehicle Distance Display Unit

Claims (9)

Photographing means for photographing the front of the host vehicle;
Storage means for storing the relationship between the size of the license plate and the distance from the host vehicle to the vehicle having the license plate in association with the aspect ratio of the license plate;
When a license plate is present in the image of the front of the host vehicle photographed by the photographing means, the relationship with the distance from the host vehicle to the vehicle having the license plate corresponding to the aspect ratio and size of the license plate The vehicle-mounted electronic device, comprising: The storage means stores the relationship between the size of the license plate and the distance from the host vehicle to the vehicle having the license plate for each of a plurality of distances,
The control means calculates the distance by comparing the size of the license plate in the image ahead of the host vehicle imaged by the imaging means with the size of the license plate stored in the storage means. The in-vehicle electronic device according to claim 1. The in-vehicle electronic device according to claim 1, wherein the aspect ratio of the license plate stored in the storage unit includes three types of large, medium, and small. The storage means, for each of a plurality of mounting positions, shows the relationship between the size of the license plate in the video imaged by the imaging means and the distance from the host vehicle to the vehicle having the license plate. Remember every aspect ratio,
The control means includes setting means for setting an attachment position of the imaging means, and obtains the distance based on the relationship stored in the storage means of the attachment position set in the setting means. The vehicle-mounted electronic device in any one of Claims 1-3. The control means includes setting means for setting an attachment position of the imaging means, and corrects the distance in consideration of a correction amount of the distance stored for each attachment position of the imaging means. The vehicle-mounted electronic device in any one of Claims 1-4. The in-vehicle electronic device according to claim 4 or 5, wherein the attachment position includes a vicinity of a front end of the vehicle and a vicinity of a front end of the vehicle. Providing a notification means,
The in-vehicle electronic device according to any one of claims 1 to 6, wherein the control unit performs control to perform notification from the notification unit when the distance is equal to or less than a preset distance. The in-vehicle electronic device according to any one of claims 1 to 7, wherein the control means changes the content of the control based on the distance according to the obtained aspect ratio of the license plate.   The program for making a computer implement | achieve the function as a vehicle-mounted electronic device in any one of Claims 1-8.

Images