JP2008082932A - Navigation device, its control method, and control program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To correct a gyro sensor effectively by detecting highly accurately a turning quantity of a user's own vehicle, regardless of an overall mounting angle of the gyro sensor, in a navigation technique. <P>SOLUTION: A turning quantity calculation means 12 detects the same characteristic point and its displacement quantity, based on each image from a camera 5 at each different point of time, and thereby calculates the turning quantity of a vehicle between each point of time (turning quantity calculation processing), and a gyro correction means 14 corrects an adjustment value of the gyro in a navigation means 10, based on the turning quantity calculated in this way and on an output value acquired from the gyro sensor 7 at a timing corresponding to the turning quantity (gyro correction processing). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an improvement in navigation technology.

  In recent years, with the development of electronic technology, the spread of navigation devices for in-vehicle use is remarkable. The navigation device displays the position and direction of the vehicle specified by GPS etc. on the surrounding map based on the road map data, and the route to the destination specified by the user by facility search or map scrolling. It is set by searching and calculating, and guidance guidance such as the direction of travel at the intersection is performed by screen display and voice output.

  In such a navigation device, the mileage is calculated from the vehicle speed pulse signal, the turning direction of the vehicle is calculated from the gyro sensor, and these are further compared with the map data (map matching), thereby the vehicle on the road. The current position and heading are determined.

  Specifically, for the turning direction, the angular velocity around the vertical axis can be detected by attaching the detection axis of the gyro sensor so as to be in the yaw angle direction of the vehicle, and this angular velocity output is integrated. Thus, the turning amount (direction) of the vehicle can be calculated. Therefore, if the detection axis of the gyro sensor deviates from the yaw angle direction of the vehicle, the vehicle turning amount cannot be calculated accurately.

  The reason for this will be described with reference to the conceptual diagram of FIG. In this figure, α1 is an angle obtained by combining a gyro sensor attachment angle in the navigation device and a navigation device attachment angle to the vehicle, and α2 is an inclination angle of a road (slope) on which the vehicle travels. In this case, the angular velocity detected by the gyro sensor is not the angular velocity ω based on the vertical axis, but the angular velocity ωα based on an axis shifted by α from the vertical axis.

On the other hand, since the map data used in the navigation device is based on two-dimensional information, the angular velocity to be obtained is the angular velocity ω based on the vertical axis. In order to obtain this, the angle α is obtained and set as an adjustment gyro angle correction value (also referred to as an offset, offset value, adjustment value), thereby correcting the direction sensor output (angle correction). do it. Specifically, this correction

ω = ωα / cosα

Can be calculated easily.

  Although there is a proposal for detecting the turning amount and the azimuth by the change amount of the image data from the in-vehicle camera without correction or offset of the azimuth sensor (see Patent Document 1), there is always an object suitable for such detection. It is not always in the image, and it is practically difficult to use regularly from the viewpoint of processing load. For this reason, grasping of the turning amount and the direction is based on a technique for correcting the output of the direction sensor, particularly the gyro sensor, which does not cause a large processing load, with an angle correction value (offset value).

JP-A-11-223530 JP-A-3-99952 JP-A-9-171348 Japanese Patent Laid-Open No. 2001-114048 JP 2001-116567 A

  However, even if the gyro sensor mounting angle in the navigation device and the navigation device mounting angle to the vehicle are measured and the sum is set as an adjustment value (gyro angle correction value), the shape of the road, The inclination of the vehicle also varies depending on various factors such as load balance of luggage, air pressure balance of each tire, acceleration and deceleration. For this reason, when the vertical direction is used as a reference, the total mounting angle of the gyro sensor is inconsistent with the set offset value, and there is a problem that an error occurs in the detected turning amount and direction. It had been.

  The present invention solves the above-mentioned problems of the prior art, and its purpose is to detect the turning amount of the own vehicle with high accuracy regardless of the total mounting angle of the gyro sensor in the navigation technology. It is to correct the gyro sensor effectively.

  In order to achieve the above object, one aspect of the navigation device of the present invention is a navigation device that provides driving assistance using a navigation sensor group including a gyro sensor and a computer, and an output value from the gyro sensor. , A navigation means for detecting a turning amount of the vehicle based on an adjustment value of a mounting angle set in advance with respect to the gyro sensor, and using it together with other navigation information to assist driving, a camera mounted on the vehicle, Based on the images from the camera at different points in time, the same feature point and the amount of displacement of the same are detected, thereby calculating the amount of turning of the vehicle and the turning calculated by the turning amount calculating means. Gyro correction means for correcting the adjustment value in the gyro processing means based on the amount and the output value from the gyro sensor; Characterized in that it has a.

  In this way, the image of the surroundings of the vehicle taken with the on-board camera for front / rear and side confirmation is processed, and the turning amount of the vehicle is calculated based on the detection of the feature points on the road surface and the amount of displacement. Based on this turning amount, it is possible to correct the adjustment value of the gyro sensor output value with high accuracy regardless of the total mounting angle of the gyro sensor, and to improve the judgment accuracy of the direction and position of the own vehicle It becomes. In addition, since the gyro sensor detects the normal turning amount other than during correction, it is possible to always detect the turning amount reliably without causing a large load such as image processing on the CPU regardless of the road surface condition. .

  In another aspect of the present invention, the turning amount calculation means further uses an overhead image conversion means for converting each image at a plurality of time points from the camera into an overhead image, and contour extraction from each overhead image. Feature point detecting means for detecting feature points, feature point matching means for detecting common feature points by pattern matching between successive images, and displacement for calculating a displacement amount from each image for the detected common feature points And a quantity calculating means.

  In this way, based on camera images at a plurality of points in time, by using conversion to a bird's-eye view image and pattern matching that are well-established in the image processing field, images from cameras installed obliquely on the vehicle However, the turning amount of the vehicle can be acquired easily and with high accuracy, and the adjustment value of the gyro sensor can be effectively corrected.

  Note that the method and program also conform to the above-described embodiments.

  As described above, according to the present invention, in the navigation technology, regardless of the total mounting angle of the gyro sensor, the turning amount of the host vehicle can be detected with high accuracy and the gyro sensor can be effectively corrected. It becomes possible.

  Next, the best mode for carrying out the present invention will be described with reference to the drawings. Note that assumptions common to the explanation in the background art and problems are omitted as appropriate.

[1. Constitution〕
A navigation device (hereinafter referred to as “this device”) in the present embodiment performs driving assistance by a computer such as route guidance to a designated destination, and the configuration of this device is shown in FIG. The configuration and processing related to general navigation, for example, facility search, destination designation reception, navigation calculation such as vehicle position estimation, route search, guidance guidance output, etc. are the same as in the past, so details are omitted. To do.

  In the configuration of the apparatus shown in FIG. 1, 1 is a control unit such as a CPU of a computer, and 2 is a storage means for road map data representing a road network structure, various facilities, and the like, such as a DVD-ROM or the like. A disk device such as an HDD is used. Reference numeral 3 denotes a display unit for screen display such as a liquid crystal panel, and reference numeral 4 denotes an operation unit for information input such as a switch or a remote control unit.

  A camera 5 is provided on the front, rear, and side of the vehicle to photograph the road surface. For example, (1) attached to the front nose and confirms the blind spot in the intersection when entering an intersection with poor visibility. (2) Camera for rearward confirmation when the vehicle is to be turned back, (3) Side view camera for mounting on a vehicle that is being studied in the driving support system, etc., on the left side of the road (opposite the driver's seat) ) Can also be shared with those who check the situation.

  The image processing unit 51 is a block that digitizes an input signal (analog) from the camera, converts it into image data, performs necessary image processing, and stores the image data in the image memory 52.

  The GPS receiver 6, the gyro sensor 7, and the vehicle speed detector 8 are a navigation sensor group. In addition, the apparatus includes an operation memory 9, a VICS receiver 10, and an input / output user interface 11.

  Further, the control unit 1 realizes the respective means 10 to 24 shown in FIG. 1 by a control program such as incorporation, and these respective means realize and execute each functional action of the present invention and this embodiment as follows. Processing means. Of these, the navigation means 10 detects the turning amount of the vehicle based on the output value transmitted from the gyro sensor 7 and the adjustment value of the attachment angle set in advance for the gyro sensor.

[2. Action)
The apparatus configured as described above operates as follows.
[2-1. Overview〕
As an outline, the turning amount calculation means 12 calculates the turning amount of the vehicle between the time points by detecting the same feature point and the displacement amount based on the images from the camera 5 at different time points. (Turning amount calculation processing) Based on the turning amount calculated in this way and the output value obtained from the gyro sensor 7 at the timing corresponding to the turning amount, the gyro correction unit 14 performs the above-described operation in the navigation unit 10. The adjustment value is corrected (gyro correction processing).

[2-2. (Operation procedure)
An operation procedure in this apparatus for realizing the above-described operation is illustrated in the flowchart of FIG. In this operation procedure, first, the turning amount calculation means 12 reads out images at a plurality of time points (time k, k + 1) from the camera 5 from the image memory 52 (steps S01 and S03), and the overhead image conversion means 21 respectively. The image is converted into a bird's-eye view image (bird's-eye view image conversion process), and the feature point detection unit 22 detects the feature point from each of these bird's-eye view images by contour extraction or the like (steps S02 and S04. Feature point detection process).

  Further, the feature point matching means 23 detects a common feature point by comparing and judging the images of the succeeding times k and k + 1 by pattern matching (step S05, feature point matching process), and the matched common feature point. , The displacement amount calculation means 24 calculates the displacement amount and the corresponding turning amount from each image (step S06, displacement amount calculation processing).

  Then, the gyro correction unit 14 reads the turning angle from the time k to k + 1 obtained by the navigation unit 10 using the gyro sensor 7, that is, the turning amount (step S07), and the relationship with the turning amount calculated in step S06 is obtained. Based on this, a correct adjustment value (gyro angle correction value) in the navigation means 10 is calculated, and correction is performed by substituting the previous adjustment value (step S08).

[2-3. Specific example of turning amount calculation)
Here, a specific example of processing for calculating the turning amount from the image will be shown. For example, FIG. 3 is an example of an image when the vehicle turns straight from a straight line captured by a side view camera. This is an example in which only contour extraction is applied to nine camera images in time series (1), (2), (3), and subsequent (9). For example, the image at time k is (1), and the image at time k + 1 is (2). In this way, the image processing unit 51 continuously acquires camera images at certain time intervals, performs image distortion according to the shooting angle, overhead view image acquisition by viewpoint conversion, contour extraction for feature point extraction, and the like, and image memory 52.

  Here, the distortion of the image refers to, for example, an object in an image captured by this camera when the camera A (mounted on the vehicle) shown in FIG. 4 is installed obliquely downward to capture a road surface. The shape of the object changes depending on the distance between each part and the camera. For example, a crosswalk composed of a plurality of rectangles also looks like a trapezoidal gathering as shown in FIG.

  The overhead view image is obtained by converting the viewpoint of the captured image, as shown by a broken line in FIG. That is. The principle and method for generating such a bird's-eye view image from the image of the camera can be appropriately selected from known ones, and examples thereof are also shown in Patent Documents 2, 3, 4, 5, etc. Yes.

  In this way, when the overhead view process is performed with the top looking down from above the vehicle, the crosswalk of the camera image as shown in FIG. 5 (1) can be converted as shown in FIG. 5 (2).

  And the schematic diagram which shows the result of having performed the above bird's-eye processing to each camera image (1)-(9) of FIG. 3 is shown in FIG. Also in this figure, frame numbers (1), (2), (3), and up to (9) show image frames corresponding to each image (time) in FIG. An image corresponding to the frame is stored.

  Then, the turning amount calculation means 12 finds feature points such as points A and B in FIG. 3 from two consecutive images in the image memory, for example, by a method such as pattern matching, and the displacement angle ( By calculating the (movement direction), the turning amount (turning angle) of the vehicle can be obtained.

  As a more specific example, for example, FIG. 7 is a conceptual diagram in which the image at time k, that is, (1) in FIG. 6 is represented by a broken line, and the image at time k + 1, that is, (2), is represented by a solid line. . In this example, the feature point A shown in FIG. 3 is a part of the stop line. In FIG. 7, the angle θ between these two feature points, that is, A in (1) and A in (2) is obtained. Corresponds to the calculation of the vehicle turning amount. This is to determine the identity between the feature point A at time k and the feature point A at time k + 1, and calculate the displacement angle (arc tangent) from the coordinate value in the image.

  Note that the turning amount θ in FIG. 7 is an angle of the oblique parallel movement from the position (1) of the broken line to the position (2) of the solid line, but since the vehicle does not travel obliquely, the angle of the oblique translation is Is substantially the amount of turning of the entire vehicle led by the front wheels. For reference, FIG. 8 shows an example in which the point of displacement is emphasized although it does not coincide with the movement of FIG. 3 or FIG.

[2-4. (Gyro correction)
Subsequently, an example of correcting the adjustment value (gyro angle correction value) for the gyro sensor 7 based on the turning amount calculated as described above and the output value obtained from the gyro sensor 7 at the timing corresponding thereto. Indicates.

  In this correction, the own vehicle obtained by integrating the true turning angle of the own vehicle obtained from the displacement angle of the same feature point in successive images and the gyro sensor output value (angular velocity) between the time points of the successive images. The angle at which the gyro sensor 7 is attached is calculated from the turning angle of the gyro sensor 7 to obtain a new angle correction value, that is, an adjustment value of the gyro sensor 7. In this example, the attachment angle of the gyro sensor 7 is expressed by a deviation from the vertical axis direction, but the actual expression format and handling in calculation are free.

  In this example, the angle θ obtained in FIG. 7 is calculated as follows in relation to the angle θg obtained by the gyro sensor process during the same period (from time k to time k + 1), and the gyro sensor angle correction value is calculated. Ask.

となる。 First, since the angle is obtained by integrating the gyro sensor output (angular velocity), the angle θg between time k and time k + 1 is

It becomes.

となる。 What is necessary is just to obtain | require the angle correction value cos (alpha) from which this (theta) g and (theta) become equal. Here, assuming that there is no angle change of the gyro sensor in the same section, the angle correction value cos α is a constant,

It becomes.

  The gyro sensor angle can be corrected from the displacement angle of the same feature point in the continuous image by the above procedure.

[3. effect〕
As described above, in the present embodiment, the image of the periphery of the vehicle captured by the vehicle camera for front / rear and side confirmation is processed, and the vehicle is detected based on the detection of the feature points on the road surface and the amount of displacement. By calculating the turning amount of the vehicle, and based on this turning amount, the adjustment value of the output value of the gyro sensor is corrected with high accuracy regardless of the total mounting angle of the gyro sensor, and the determination accuracy of the direction and position of the own vehicle Can be improved. In addition, since the gyro sensor detects the normal turning amount other than during correction, it is possible to always detect the turning amount reliably without causing a large load such as image processing on the CPU regardless of the road surface condition. .

  Further, in this embodiment, a camera installed obliquely on a vehicle by using a camera image at a plurality of points in time and conversion to a bird's-eye image and pattern matching, which are well established in the image processing field. Even from this image, the turning amount of the vehicle can be acquired easily and with high accuracy, and the adjustment value of the gyro sensor can be effectively corrected.

[4. Other embodiments]
In addition, this invention is not limited to the said embodiment, The thing illustrated below and other embodiment other than that are included. For example, the classification and order of the units (processes) 21 to 24 included in the turning amount calculation unit 12 are not strict. For example, the angle of overhead image conversion is determined by contour extraction, or the pattern matching between images Implementation can be performed in any order or configuration according to the processing procedure, such as using a contour portion as a feature point.

  Moreover, although the said embodiment mainly demonstrated the navigation apparatus in mind, it can also grasp | ascertain as a method and computer program corresponding to such a navigation apparatus, for example, it downloads with charge free of charge for the existing navigation apparatus The provided program for updating and the like is also one embodiment of the present invention.

The functional block diagram which shows the structure of embodiment of this invention. The flowchart which shows the process sequence which correct | amends the attachment angle of the gyro in embodiment of this invention. The figure which illustrates the continuous image by the camera image | video at the time of vehicle left turn in embodiment of this invention. The conceptual diagram explaining the bird's-eye view process in embodiment of this invention. The conceptual diagram which illustrates the bird's-eye view process in embodiment of this invention. The schematic diagram which illustrates the continuous image at the time of the vehicle left turn which carried out the overhead view process of the continuous image of FIG. The conceptual diagram which shows the example which overlap | superposed the image in two time points among the schematic diagrams of FIG. In embodiment of this invention, the conceptual diagram which shows the other example which superimposed the image in two time points (what emphasized the displacement by turning). The conceptual diagram which shows the example of the angular velocity which the vehicle and gyroscope which are drive | working on an inclined road detect.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Control part 2 ... Memory | storage means 3 ... Display part 4 ... Operation part 5 ... Camera 6 ... GPS receiver 7 ... Gyro sensor 8 ... Vehicle speed detector 9 ... Memory 10 ... Navigation means 11 ... User interface 12 ... Turning amount calculation means 14 ... Gyro correction means 21 ... Overhead image conversion means 22 ... Feature point detection means 23 ... Feature point matching means 24 ... Displacement amount calculation means 51 ... Image processing section 52 ... Image memory

Claims (6)

In a navigation device that performs driving support using a navigation sensor group including a gyro sensor and a computer,
Navigation means for detecting a turning amount of the vehicle based on an output value from the gyro sensor and an adjustment value of a mounting angle set in advance with respect to the gyro sensor, and using the navigation information together with other navigation information to provide driving support; ,
A camera mounted on the vehicle,
Turn amount calculation means for calculating the turn amount of the vehicle by detecting the same feature point and its displacement amount based on each image from the camera at each different time point;
Gyro correction means for correcting the adjustment value in the navigation means based on the turning amount calculated by the turning amount calculation means and the output value from the gyro sensor;
A navigation device comprising: The turning amount calculating means includes
Overhead image conversion means for converting each image at a plurality of time points from the camera into an overhead image,
Feature point detecting means for detecting feature points from each overhead image using contour extraction;
Feature point matching means for detecting a common feature point by pattern matching between successive images;
A displacement amount calculating means for calculating a displacement amount from each image for the detected common feature point;
The navigation device according to claim 1, comprising: Driving assistance using a navigation sensor group including a gyro sensor and a computer,
Navigation means for detecting a turning amount of the vehicle based on an output value from the gyro sensor and an adjustment value of a mounting angle set in advance with respect to the gyro sensor, and using the navigation information together with other navigation information to provide driving support; ,
A camera mounted on the vehicle,
In a method for controlling a navigation device having:
A turn amount calculation process for calculating a turn amount of the vehicle by detecting the same feature point and its displacement amount based on each image from the camera at each different time point;
A gyro correction process for correcting the adjustment value in the navigation means based on the turning amount calculated in the turning amount calculation process and the output value from the gyro sensor;
A method for controlling a navigation device, comprising: The turning amount calculation process includes:
Overhead image conversion processing for converting each image at a plurality of time points from the camera into an overhead image,
Feature point detection processing for detecting feature points from each overhead image using contour extraction;
A feature point matching process that detects a common feature point by pattern matching between successive images,
A displacement amount calculation process for calculating a displacement amount from each image for the detected common feature point;
The navigation apparatus control method according to claim 3, further comprising: Driving assistance using a navigation sensor group including a gyro sensor and a computer,
Navigation means for detecting a turning amount of the vehicle based on an output value from the gyro sensor and an adjustment value of a mounting angle set in advance with respect to the gyro sensor, and using the navigation information together with other navigation information to provide driving support; ,
A camera mounted on the vehicle,
In a control program for a navigation device having
The program realizes a turning amount calculation means and a gyro correction means by controlling the control unit of the computer,
Causing the turning amount calculation means to perform a turning amount calculation process for calculating the turning amount of the vehicle by detecting the same feature point and its displacement amount based on each image from the camera at different time points;
The gyro correction means causes the gyro correction process to correct the adjustment value in the navigation means based on the turning amount calculated in the turning amount calculation process and the output value from the gyro sensor. Control program for navigation device. In the turning amount calculation process, the turning amount calculation means includes:
Overhead image conversion processing for converting each image at a plurality of time points from the camera into an overhead image,
Feature point detection processing for detecting feature points from each overhead image using contour extraction;
A feature point matching process that detects a common feature point by pattern matching between successive images,
A displacement amount calculation process for calculating a displacement amount from each image for the detected common feature point;
The navigation apparatus control program according to claim 5, wherein:

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