JP2012103199A - On-vehicle information device and navigation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an on-vehicle information device that can compute a travel distance of a vehicle with high accuracy during a period in which pulse omission of vehicle speed pulse occurs.SOLUTION: A control part 10 of an on-vehicle information device 1 obtains photographic images of a wheel 21 imaged by a camera 23. The control part 10 obtains the number of rotations of the wheel 21 on the basis of a pattern matching of the obtained photographic images with template images of the wheel 21 stored in a template database 111 of a storage part 11. The control part 10 can compute a travel distance of a vehicle 2 by multiplying the number of rotations of the obtained wheels 21 by a certain coefficient when a pulse omission of a vehicle speed pulse occurs supplied from a vehicle speed sensor 22.

Description

  The present invention relates to an in-vehicle information device and a navigation device.

  In a vehicle speed sensor that detects the rotation of an axle and outputs a vehicle speed pulse corresponding to the rotation, a phenomenon of missing a pulse that does not output a vehicle speed pulse occurs when the vehicle is traveling at a low speed. Patent Document 1 discloses a system that estimates the travel distance based on vehicle speed pulses before and after the occurrence of pulse omission and calculates the current position of the vehicle even if such a pulse omission occurs during low-speed running.

JP 2000-97713 A

  However, in the method of Patent Document 1, the travel behavior of the vehicle before and after the period (including vehicle speed pulses) is used for estimating the travel distance in the period in which the missing pulse occurs, The driving behavior was not used. Therefore, there is a possibility that the travel distance estimated by the method of Patent Document 1 is far from the travel distance traveled during the period when the pulse missing actually occurs. An object of the present invention is to provide an in-vehicle information device capable of calculating the travel distance of a vehicle with high accuracy during a period in which a missing pulse has occurred.

  The in-vehicle information device of the present invention is an on-vehicle information device mounted on a vehicle, and includes a pulse acquisition means for acquiring a vehicle speed pulse corresponding to the traveling speed of the vehicle, and a vehicle wheel imaged by a camera installed in the vehicle. A captured image acquisition means for acquiring a captured image including at least a part of the rotation speed, a rotational speed acquisition means for acquiring the rotational speed of the wheel based on the captured image, and the number of vehicle speed pulses acquired by the pulse acquisition means. Is less than the first pulse number, the travel distance is calculated based on the number of rotations of the wheel, and when the number of vehicle speed pulses per unit time is equal to or greater than the first pulse number, the travel distance is calculated based on the vehicle speed pulse. Mileage calculating means for calculating

  It is possible to calculate the travel distance of the vehicle during the period when the missing pulse is occurring with high accuracy.

It is a block diagram which shows an example of a structure of the vehicle-mounted information apparatus by one embodiment of this invention. It is a figure which shows an example of the wheel which consists of a wheel and a tire. It is a graph which shows an example of the relationship between the number of vehicle speed pulses and the travel speed of a vehicle. It is an example of the flowchart regarding the process which calculates the travel distance of a vehicle. FIG. 5 is a continuation of FIG. 4, and is an example of a flowchart relating to a process for calculating the travel distance of the vehicle.

  A configuration of an in-vehicle information device according to an embodiment of the present invention will be described with reference to FIG. The in-vehicle information device 1 of the present embodiment is mounted on a vehicle 2 and calculates the travel distance of the vehicle 2. In FIG. 1, a navigation device including a control unit 10, a storage unit 11, and a gyro sensor 12 is shown as a configuration example of the in-vehicle information device 1.

  The control unit 10 of the in-vehicle information device 1 is a part for executing various processes and controls for operating the in-vehicle information device 1, and includes a microprocessor, various peripheral circuits, a RAM, a ROM, and the like.

  The storage unit 11 of the in-vehicle information device 1 stores various information and settings for operating the in-vehicle information device 1, and is configured by a hard disk or the like.

  The gyro sensor 12 of the in-vehicle information device 1 is a sensor for detecting an angular velocity corresponding to a change in the direction of the vehicle 2. The gyro sensor 12 outputs an output signal corresponding to the angular velocity of the vehicle 2 to the control unit 10. The control unit 10 can acquire an output signal corresponding to the angular velocity of the vehicle 2 transmitted from the gyro sensor 12.

  The vehicle speed sensor 22 is a sensor that is mounted on the vehicle 2 and outputs a vehicle speed pulse that is an output signal corresponding to the rotation of the axle of the vehicle 2. The vehicle speed sensor 22 and the in-vehicle information device 1 are connected wirelessly or by wire. The controller 10 can acquire the vehicle speed pulse output from the vehicle speed sensor 22.

  The control unit 10 acquires output signals from the vehicle speed sensor 22 and the gyro sensor 12, and calculates the distance traveled by the vehicle 2 and the travel direction based on the output signals. Then, the current position of the vehicle 2 can be calculated based on the calculated travel distance and travel direction of the vehicle 2.

  A vehicle 2 shown in FIG. 1 is a four-wheeled vehicle and includes four wheels 21 including tires and wheels. The camera 23 is photographing the wheel 21 of the vehicle 2. The camera 23 and the in-vehicle information device 1 are connected wirelessly or by wire. The camera 23 outputs captured images obtained by capturing the wheels 21 to the in-vehicle information device 1 for each frame rate. The control unit 10 can acquire the output captured image. One camera 23 is provided, for example, on each of the left and right door mirrors in front of the vehicle body. The camera 23 photographs each rear wheel of the vehicle 2 and transmits a captured image of the rear wheel to the in-vehicle information device.

  The vehicle speed sensor 22 outputs a predetermined number of pulses each time the axle rotates once. The vehicle speed pulse output per unit time from the vehicle speed sensor 22 increases as the traveling speed of the vehicle increases. The vehicle speed pulse output from the vehicle speed sensor 22 is generated by, for example, shaping an analog signal generated with the rotation of the axle. It is known that when the traveling speed of the vehicle 2 decreases and the axle rotation speed decreases, the period of the analog signal becomes longer, the number of vehicle speed pulses decreases, and at the same time the amplitude of the analog signal decreases. In the vehicle speed sensor 22, when the amplitude of the analog signal becomes smaller than a predetermined threshold, a vehicle speed pulse is not generated and is not output. A situation in which a vehicle speed pulse is not output even though the vehicle 2 is traveling as described above is referred to as missing pulse.

  When the missing pulse occurs in the navigation device, the control unit 10 may determine that the vehicle 2 is stopped even though the vehicle 2 is traveling. As a result, the travel distance and current position calculated by the vehicle 2 may be inaccurate.

  Conventionally, the current position of the vehicle 2 is specified by map matching processing based on GPS signals from GPS satellites, and the current position and travel distance of the vehicle 2 are corrected. However, there are no maps such as parking lots or in tunnels. Map matching processing cannot be performed in places where GPS signals cannot be received.

  The in-vehicle information device 1 of the present embodiment can correctly calculate the travel distance of the vehicle 2 at any location by calculating the travel distance of the vehicle 2 based on the image taken by the camera 23. Then, the control unit 10 can calculate or correct the current position of the vehicle 2 at any location using the travel distance calculated based on the captured image of the camera 23. Various methods are known for calculating or correcting the current position using the travel distance, and these may be used.

  In the storage unit 11 of the present embodiment, a template image of the wheel 21 used for the pattern matching process of the wheel 21 is stored. In the present embodiment, it is assumed that the template image is stored in advance in the template database 111 stored in the storage unit 11. The template image of the wheel 21 is, for example, an image related to the spoke pattern of the wheel, and may be a black and white grayscale image or a color image, and may be an entire image or a partial image of the wheel.

  A template image of the wheel 21 will be described with reference to FIG. FIG. 2 is a diagram illustrating a wheel 21 including a tire 211 and a wheel 212. The wheel 212 in FIG. 2 has four spokes 213. When the partial image of the wheel 212 is used as a template image, for example, the range of the partial region 214 in FIG. 2 is stored as a template image.

  The control unit 10 performs pattern matching between the captured image and the template image every time a captured image of the wheel 21 is output from the camera 23. When the ignition switch of the vehicle 2 is turned on, the control unit 10 acquires a captured image of the wheel 21 captured by the camera 23, and performs pattern matching between the captured image and the template image of the wheel 21 stored in the template database 111. As a result, the template image most similar to the wheel 21 is selected from the template database 111.

  When the vehicle 2 is traveling, the control unit 10 performs pattern matching between the captured image of the wheel 21 captured by the camera 23 and the template image selected when the ignition switch of the vehicle 2 is turned on. The rotation of the wheel 21 is detected and the rotation number is acquired. For example, the rotation speed of the wheel 21 is acquired based on the number of passes of the spokes 213 of the wheel 212 through a predetermined range on the photographed image of the camera 23.

  The control unit 10 calculates the travel distance of the vehicle 2 by multiplying the acquired rotation speed by an average distance coefficient calculated in advance. The number of rotations of the wheel 21 that can be acquired by this method increases as the vehicle 2 travels at a low speed. A method for calculating the average distance coefficient will be described later.

  The control unit 10 can also calculate the travel distance of the vehicle 2 based on the vehicle speed pulse output from the vehicle speed sensor 22. The traveling distance of the vehicle 2 calculated based on the vehicle speed pulse is less accurate if a pulse drop occurs when the vehicle 2 is traveling at a low speed.

  In the in-vehicle information device 1 of the present embodiment, the method for calculating the travel distance based on the above-described captured image of the wheel 21 and the method for calculating the travel distance based on the vehicle speed pulse of the vehicle speed sensor 22 are controlled. Depending on the number of vehicle speed pulses acquired by the unit 10 per unit time.

  A method of using the two methods based on the number of vehicle speed pulses per unit time will be described with reference to FIG. FIG. 3 shows an example of the relationship between the traveling speed of the vehicle 2 and the number of vehicle speed pulses per unit time acquired by the control unit 10 of the in-vehicle information device 1. The horizontal axis in FIG. 3 represents the traveling speed of the vehicle 2, and the vertical axis represents the number of vehicle speed pulses per unit time acquired by the control unit 10.

  In FIG. 3, when the traveling speed of the vehicle 2 is equal to or higher than the speed V2, the relationship between the traveling speed of the vehicle 2 and the number of acquired vehicle speed pulses is stable with a constant slope. Then, when the traveling speed of the vehicle 2 becomes less than the speed V2, the pulse missing starts to occur, and when the traveling speed becomes less than the speed V1, the control unit 10 cannot acquire the vehicle speed pulse due to the missing pulse. The values of the speed V1 and the speed V2 vary depending on the vehicle speed sensor 22, and for example, the speed V1 is about 2 km / h and the speed V2 is about 5 km / h.

  In FIG. 3, the speed range where the traveling speed of the vehicle 2 is less than the speed V2 is a speed range R1, and the speed range which is equal to or higher than the speed V2 is a speed range R2. When the traveling speed of the vehicle 2 is in the speed range R1, the control unit 10 calculates the traveling distance of the vehicle 2 based on the captured image of the camera 23. When the traveling speed of the vehicle 2 is in the speed range R2, the traveling distance of the vehicle 2 is calculated based on the vehicle speed pulse of the vehicle speed sensor 22.

  Whether the traveling speed of the vehicle 2 is in the speed range shown in FIG. 3 is determined based on the number of vehicle speed pulses per unit time acquired by the control unit 10. In FIG. 3, the number of vehicle speed pulses per unit time when the traveling speed of the vehicle 2 is V2 is P2. At this time, the traveling speed of the vehicle 2 is assumed to be within the range of the speed range R1 when the number of vehicle speed pulses per unit time is less than P2, and within the range of the speed range R2 when the number of vehicle speed pulses is P2 or more. It shall be in.

  The control unit 10 calculates an average distance coefficient used when calculating the travel distance of the vehicle 2 based on the number of rotations of the wheels 21 when the travel speed of the vehicle 2 is within the speed range R3 of FIG. The speed range R3 is a range from a speed V2 at which the effect of missing pulses starts to a speed V3 at which the rotational speed of the wheel 21 can be reliably acquired. The value of the speed V3 is a speed based on the performance of the camera 23 and the number of feature points of the template image determined at the time of activation, and is about 10 km / h, for example. The value of the speed V3 increases as the performance of the camera 23 increases and the number of feature points of the template image determined at the time of activation decreases. Whether or not the traveling speed of the vehicle 2 is within the speed range R3 is also determined based on the number of vehicle speed pulses per unit time acquired by the in-vehicle information device 1. In FIG. 3, the number of vehicle speed pulses per unit time when the traveling speed of the vehicle 2 is the speed V3 is P3.

  The average distance coefficient is calculated based on the number of rotations of the wheels 21 per unit time when the traveling speed of the vehicle 2 is within the speed range R3 and the distance traveled by the vehicle 2 per unit time.

  For example, the average distance coefficient is calculated by the control unit 10 as follows. In the method described below, the distance coefficient k is calculated based on the number of rotations of the wheels 21 per unit time when the traveling speed of the vehicle 2 is within the speed range R3 and the distance traveled by the vehicle 2. The average distance coefficient is calculated by calculating an average value including the distance coefficient k calculated in the past. The distance coefficient k calculated in the past may be stored in the storage unit 11.

  The distance coefficient k is calculated by the following method. First, the control unit 10 detects that the traveling speed of the vehicle 2 is within the speed range R3 based on the number of vehicle speed pulses acquired per unit time. Next, when the traveling speed of the vehicle 2 is within the range of the speed range R3, the number of rotations of the wheels 21 per unit time and the distance traveled by the vehicle 2 per unit time are acquired. Then, the distance coefficient k is calculated by substituting the obtained travel distance and rotation speed per unit time into the following mathematical formula (1). In Equation (1), d is the travel distance of the vehicle 2 per unit time, and r is the number of rotations of the wheels 21 per unit time.

  k = d / r (1)

  The average distance coefficient, which is an average value of the distance coefficient k, is calculated by, for example, dividing the sum of the distance coefficients k calculated in the past for the wheel 21 by the number of times the distance coefficient k is calculated for the wheel 21. The calculated average distance coefficient is stored in a predetermined storage area of the storage unit 11, and is acquired from the storage unit 11 when the travel distance of the vehicle 2 is calculated based on the number of rotations of the wheels 21.

  The number of times the distance coefficient k used for calculating the average distance coefficient is calculated is stored in the storage unit 11 in the same manner as the average distance coefficient, and each time the distance coefficient k is calculated based on Equation (1), the control unit 10 Is incremented by one.

  The number of times of calculating the average distance coefficient and the distance coefficient k stored in the storage unit 11 is preferably initialized to 0 when the tires or wheels of the wheels 21 are changed. This is because the diameter or the like of the wheel 21 changes when the tire or the wheel of the wheel 21 is changed. Here, when the tire or wheel is changed, for example, when it is replaced with a studless tire in winter. If the tire or the wheel is changed, it is determined that there is a change when the template image selected when the ignition switch of the vehicle 2 is turned on is different from the template image selected last time. Good.

  The process for calculating the travel distance of the vehicle 2 described above will be described with reference to FIGS. 4 and 5. 4 and 5 are flowcharts illustrating an example of a process for calculating the travel distance of the vehicle 2 that is executed by the control unit 10. 4 and 5 is a process executed by the control unit 10 and starts from step S101 in FIG. 4 when the ignition switch of the vehicle 2 is turned on.

  In step S <b> 101 of FIG. 4, the control unit 10 starts acquiring vehicle speed pulses from the vehicle speed sensor 22. When the control unit 10 starts acquiring the vehicle speed pulse, the process proceeds to step S102.

  In step S <b> 102 of FIG. 4, the control unit 10 starts acquiring a captured image of the wheel 21 from the camera 23. The control part 10 will advance a process to step S103, if acquisition of the picked-up image of the wheel 21 is started.

  In step S103 of FIG. 4, the control unit 10 selects, from the template images stored in the template database 111, the one most similar to the captured image of the wheel 21 acquired in step S102 by pattern matching processing. . When the control unit 10 selects a template image that is most similar to the captured image of the wheel 21, the process proceeds to step S104.

  In step S104 of FIG. 4, the control unit 10 starts acquiring the rotation speed of the wheel 21 by pattern matching between the captured image of the wheel 21 and the template image determined in step S103. The control part 10 will advance a process to step S105, if acquisition of the rotation speed of the wheel 21 is started.

  In step S105 of FIG. 4, the control unit 10 determines whether or not the number of vehicle speed pulses per unit time is less than P2. If the number of vehicle speed pulses per unit time is less than P2, the control unit 10 proceeds to step S106, and if the number of vehicle speed pulses per unit time is equal to or greater than P2, the process proceeds to step S201 in FIG. .

  In step S <b> 106 of FIG. 4, the control unit 10 acquires an average distance coefficient calculated in advance from the storage unit 11. After acquiring the average distance coefficient, the control unit 10 advances the process to step S107.

  In step S107 in FIG. 4, the control unit 10 calculates the travel distance of the vehicle 2 based on the number of rotations of the wheels 21 per unit time and the average distance coefficient acquired in step S106. For example, the travel distance of the vehicle 2 is calculated by multiplying the number of rotations of the wheels 21 per unit time by an average distance coefficient. After calculating the travel distance of the vehicle 2, the control unit 10 returns the process to step S105.

  In step S201 in FIG. 5, the control unit 10 calculates the travel distance of the vehicle 2 based on the number of vehicle speed pulses per unit time. After calculating the travel distance of the vehicle 2 based on the number of vehicle speed pulses per unit time, the control unit 10 advances the process to step S202. Various methods for calculating the travel distance of the vehicle 2 based on the number of vehicle speed pulses are known, and these methods are used.

  In step S202 of FIG. 5, the control unit 10 determines whether or not the number of vehicle speed pulses per unit time is less than P3. When the number of vehicle speed pulses per unit time is less than P3, the control unit 10 advances the process to step S203, and when the number of vehicle speed pulses per unit time is P3 or more, the process returns to step S105 of FIG. .

  In step S203 in FIG. 5, the control unit 10 calculates the distance coefficient k by substituting the number of rotations of the wheel 21 per unit time and the travel distance calculated in step S201 into Equation (1). After calculating the distance coefficient k, the control unit 10 advances the process to step S204.

  In step S <b> 204 of FIG. 5, the control unit 10 acquires the number of times the average distance coefficient and the distance coefficient k are calculated from the storage unit 11. After acquiring the average distance coefficient, the control unit 10 advances the process to step S205.

In step S205 of FIG. 5, the control unit 10 uses the following formula (2) based on the distance coefficient k calculated in step S203 and the average distance coefficient and the number of times the distance coefficient k acquired in step S204 is calculated. An average distance coefficient is calculated. In Equation (2), K is the average distance coefficient calculated in step S205, Ko is the average distance coefficient acquired in step S204, and N is the number of times the distance coefficient k acquired in step S204 is calculated. After calculating the average distance coefficient K, the control unit 10 advances the process to step S206.
K = (Ko × N + k) / (N + 1) (2)

  In step S206 of FIG. 5, the control unit 10 increases the number of times the distance coefficient k acquired from the storage unit 11 in step S204 is calculated by one. When the number of times the distance coefficient k has been calculated is increased by 1, the control unit 10 advances the process to step S207.

  In step S207 of FIG. 5, the control unit 10 stores in the storage unit 11 the number of times the average distance coefficient calculated in step S205 and the distance coefficient k calculated in step S206 have been calculated. When the number of times the average distance coefficient and the distance coefficient k are stored is stored in the storage unit 11, the control unit 10 returns to step S105 in FIG.

  According to each embodiment explained above, the following operation effect is produced.

[1] In the in-vehicle information device 1 according to the embodiment of the present invention, the control unit 10 acquires a vehicle speed pulse from the vehicle speed sensor 22 (step S101 in FIG. 4), and captures a captured image of the wheel 21 captured by the camera 23. Obtain (step S102 in FIG. 4). The control unit 10 acquires the rotational speed of the wheel 21 based on the pattern matching result between the captured image of the wheel 21 and the template image stored in the template database 111 of the storage unit 11 (step S104 in FIG. 4). When the number of vehicle speed pulses acquired per unit time is less than P2 (YES in step S105 in FIG. 4), the control unit 10 multiplies the rotation speed of the wheels 21 by the average distance coefficient to calculate the travel distance of the vehicle 2. When calculated (step S107 in FIG. 4) and the number of vehicle speed pulses per unit time is equal to or greater than P2 (NO in step S105 in FIG. 4), the travel distance traveled by the vehicle 2 is calculated based on the vehicle speed pulses ( Step S201 in FIG. Thereby, even if a pulse drop occurs, the travel distance can be calculated with high accuracy.

[2] In the in-vehicle information device 1, when the number of vehicle speed pulses acquired per unit time is greater than or equal to P2 and less than P3 (step S105 NO in FIG. 4, YES in step S202 in FIG. 5), the control unit 10 An average distance coefficient is calculated based on the travel distance of the vehicle per unit time calculated based on the vehicle speed pulse output from the vehicle 22 and the number of rotations of the wheel 21 per unit time (step S205 in FIG. 5). Thereby, the rotation speed of the wheel 21 can be converted into a travel distance traveled by the vehicle 2.

  Each of the above embodiments can be modified as follows.

[1] In the present embodiment, the template image stored in the template database 111 is a wheel image. However, if the rotation of the axle on which the wheel 21 is mounted can be determined based on the captured image, Not limited to wheels. For example, a tire or the like that is marked so as to be used as a feature at a predetermined position may be used.

[2] In the present embodiment, the template image is selected from those stored in the template database 111. However, the template image is a photographed image of the wheel 21 taken when the ignition switch of the vehicle 2 is turned on. The based image may be a template image.

[3] In the present embodiment, the in-vehicle information device 1 is a navigation device, but is an external device that outputs the calculation result of the travel distance of the vehicle 2 to the navigation device or an ECU (Engine Control Unit) of the vehicle 2. Also good.

[4] The position of the camera 23 is not limited to the door mirror of the vehicle 2. For example, the back surface of the wheel 21 may be photographed from under the vehicle body of the vehicle 2. In this case, it is desirable to provide illumination for photographing at the same time. When the image is taken from under the vehicle body of the vehicle 2, one camera 23 may be used.

[5] In the present embodiment, the travel distance of the vehicle 2 is calculated based on the change in the rotation speed of the wheel 21 acquired based on the captured image from the camera 23. However, the acceleration and travel speed of the vehicle 2 are calculated. However, it may be used as an alternative to an acceleration sensor or a vehicle speed sensor mounted on the vehicle 2.

[6] Although the vehicle 2 is a four-wheeled vehicle in the present embodiment, the present invention is not limited to this. For example, a motorcycle may be used.

  Each embodiment and various modifications described above are merely examples, and the present invention is not limited to these contents as long as the features of the invention are not impaired.

DESCRIPTION OF SYMBOLS 1 Car information system 2 Vehicle 10 Control part 11 Memory | storage part 12 Gyro sensor 21 Wheel 22 Vehicle speed sensor 23 Camera 111 Template database 211 Tire 212 Wheel 213 Spoke

Claims (9)

An in-vehicle information device mounted on a vehicle,
Pulse acquisition means for acquiring a vehicle speed pulse according to the traveling speed of the vehicle;
A captured image acquisition means for acquiring a captured image including at least a part of a wheel of the vehicle captured by a camera installed in the vehicle;
A rotational speed acquisition means for acquiring the rotational speed of the wheel based on the captured image;
When the number of vehicle speed pulses per unit time acquired by the pulse acquisition unit is less than the first number of pulses, the travel distance is calculated based on the number of rotations of the wheels, and the vehicle speed per unit time is calculated. An in-vehicle information device comprising travel distance calculation means for calculating the travel distance based on the vehicle speed pulse when the number of pulses is equal to or greater than the first pulse number. The in-vehicle information device according to claim 1,
Coefficient calculation means for calculating a coefficient according to the ratio between the rotation speed of the wheel and the travel distance,
The travel distance calculating means calculates the travel distance based on the rotation speed of the wheel and the coefficient when the number of the vehicle speed pulses per unit time is equal to or greater than the first pulse number. In-vehicle information device. The in-vehicle information device according to claim 2,
The coefficient calculation means is calculated by the travel distance calculation means based on the vehicle speed pulse when the number of the vehicle speed pulses per unit time is equal to or greater than the first pulse and less than a predetermined second pulse number. The vehicle information apparatus characterized in that the coefficient is calculated based on a travel distance and a rotation speed of the wheel when traveling the travel distance. The in-vehicle information device according to claim 2 or 3,
A change determination unit that determines whether or not the wheel has been changed based on a captured image acquired by the captured image acquisition unit when the vehicle is started;
The on-vehicle information device characterized in that the coefficient calculation means initializes the coefficient when the change determination means determines that the wheel has been changed. In the in-vehicle information device according to any one of claims 1 to 4,
Image storage means for storing in advance a template image of the wheel;
The in-vehicle information device characterized in that the rotational speed acquisition means performs pattern matching between the captured image and the template image, and acquires the rotational speed of the wheel based on the result. The in-vehicle information device according to claim 5,
The image storage means stores a plurality of the template images in advance,
The rotation speed acquisition unit is configured to select a template image used for the pattern matching based on the captured image acquired by the captured image acquisition unit when the vehicle is started, from among a plurality of template images stored in the image storage unit. An in-vehicle information device characterized by being selected from. The in-vehicle information device according to claim 5,
The in-vehicle information device, wherein the image storage unit stores an image based on a captured image acquired by the captured image acquisition unit when the vehicle is started as the template image. In the in-vehicle information device according to any one of claims 1 to 7,
The on-vehicle information device, wherein the camera is attached to a door mirror of the vehicle. A navigation device mounted on a vehicle,
The in-vehicle information device according to any one of claims 1 to 8,
Position detecting means for detecting the position of the vehicle;
A navigation apparatus, further comprising: a vehicle position correction unit that corrects the position of the vehicle detected by the position detection unit based on the travel distance calculated by the travel distance calculation unit.

Images