JP2011230615A - Parking support device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a parking support device not applying an uncomfortable feeling to a driver by not showing an expected trajectory when a vehicle is in parallel to right and left white lines of a parking frame.SOLUTION: In a parking support device including an imaging unit, a display unit, a steering angle detector, and an expected trajectory drawing unit, the parking support device further includes an image conversion unit for converting a rearward image picked up by the imaging unit into a bird's-eye view image, a white line detector for detecting right and left white lines of a parking frame from the bird's-eye view image converted by the image conversion unit, and a parallel determination unit for determining whether or not a vehicle is in parallel to the right and left white lines of the parking frame detected by the white line detector. The expected trajectory drawing unit does not draw any expected trajectory when the parallel determination unit determines that the vehicle is in parallel to the right and left white lines of the parking frame.

Description

  The present invention relates to a parking assistance device, and more particularly to a parking assistance device that appropriately displays an expected trajectory of a vehicle with respect to a parking frame when the vehicle is parked in a parking frame, and supports driving during parking.

  Some vehicles are equipped with a parking assist device that displays a rear image of the vehicle on a display means in order to assist driving during parking. Some parking assist devices calculate an expected trajectory when the vehicle moves backward based on the steering angle of the vehicle, and display the expected trajectory superimposed on the rear image of the vehicle.

JP 2005-335444 A

In the parking assistance device that displays an expected trajectory in the rear image of the vehicle, when the vehicle and the white line of the parking frame are not parallel to each other but in an oblique state at the initial stage of the parking driving operation (when approaching the parking frame) Therefore, even if the predicted trajectory of the vehicle is curved toward the white line of the parking frame, the driver does not feel uncomfortable because the driver performs steering operation with the intention of turning back and forth.
On the other hand, in the final stage of the parking driving operation (immediately before entering the parking frame), the vehicle and the white line of the parking frame are often parallel to each other, and the driver intends to move the vehicle straight forward and backward. . At this time, if the steering angle is not parallel to the vehicle, the driver will feel uncomfortable because the expected trajectory is displayed in a curved state even though the driver intends to go straight ahead and back. .
Thus, in the conventional parking assistance device, even if the vehicle is about to be parked and the white lines on the left and right of the parking frame are parallel, the expected trajectory of the vehicle is continuously displayed, and therefore the steering angle is not parallel to the vehicle. However, although the driver intends to go straight ahead and back, a curved expected trajectory is displayed, which causes the driver to feel uncomfortable.

  An object of the present invention is to provide a parking assist device that prevents a driver from feeling uncomfortable by preventing an expected trajectory from being displayed when a vehicle and white lines on the left and right of a parking frame are parallel to each other. .

  The present invention is detected by an imaging means for imaging the rear of the vehicle, a display means for displaying an image captured by the imaging means, a steering angle detection means for detecting the steering angle of the vehicle, and the steering angle detection means. In a parking assistance apparatus comprising an expected trajectory drawing unit that calculates an expected trajectory of a vehicle based on the steering angle and draws it on an image displayed by the display unit, the rear image captured by the imaging unit is used as an overhead image. The image conversion means for converting, the white line detection means for detecting the left and right white lines of the parking frame from the overhead image converted by the image conversion means, and the vehicle with respect to the left and right white lines of the parking frame detected by the white line detection means Parallel prediction means for determining whether or not the vehicle is parallel, and the predicted trajectory drawing means determines that the vehicle is parallel to the left and right white lines of the parking frame by the parallel determination means. It is characterized in that it does not draw the expected trajectory.

  The parking assist device of the present invention does not display an expected trajectory when the vehicle and the left and right white lines of the parking frame are parallel to each other, so that a curved expected trajectory is not displayed for a driver who intends to go straight ahead. , The driver can be prevented from feeling uncomfortable.

It is a system block diagram of a parking assistance apparatus. Example 1 It is a control flowchart of a parking assistance apparatus. Example 1 It is a top view which shows a vehicle and a parking frame. Example 1 It is a figure which shows a back image. Example 1 It is a figure which shows the bird's-eye view image of the horizontal edge of a white line. Example 1 It is a figure which shows the coordinate system of the white line detection by Hough transformation. Example 1 It is a figure which shows the image which has the vehicle and the parking frame in the diagonal state, and displayed the prediction locus | trajectory. Example 1 It is a figure which shows the image which has the vehicle and the parking frame in a parallel state, and did not display the prediction locus. Example 1 It is a figure which shows the image which displayed the steering angle and the steering direction. Example 1 It is a system block diagram of a parking assistance apparatus. (Example 2) It is a control flowchart of a parking assistance apparatus. (Example 2) It is a figure which shows the image coordinate system at the time of the detection of a white line end point. (Example 2) It is a figure which shows the small area | region set on the window of a white line. (Example 2) It is a figure which shows the difference value of the small area | region which a window adjoins. (Example 2) It is a figure explaining the determination of the display / non-display of the expected locus by the distance between the white line end point and the vehicle rear end. (Example 2)

  In order to improve the accuracy of the switching timing of the image, the present invention detects the white line and the white line end point from the captured rear image of the host vehicle, and uses the detected white line and white line end point as the switching timing of the image display. It is realized by using.

1 to 9 show Embodiment 1 of the present invention. In FIG. 3, 1 is a parking lot, 2 is a parking frame, 3 and 4 are white lines on the left and right that are parallel to each other with a predetermined length, and 5 and 6 are white lines 3 and 4 at the rear end of the parking frame 2. Left and right wheel stops arranged at right angles, 7 is a vehicle. The vehicle 7 is equipped with a parking assistance device 8 that assists the driving operation when parking in the parking frame 2. As shown in FIG. 1, the parking assist device 8 includes an imaging unit 9 that captures the rear of the vehicle 7, a display unit 10 that displays an image captured by the imaging unit 9, and the steering angle of the steering wheel of the vehicle 7. And a control means 12 for displaying driving support information on the display means 10 based on signals input from the imaging means 9 and the steering angle detection means 11.
The imaging means 9 is composed of an imaging device such as a super wide-angle back camera attached to the rear part of the vehicle 7. In addition to providing a dedicated display device, the display means 10 can use a monitor or the like of a car navigation system disposed in the passenger compartment of the vehicle 7. The steering angle detection means 11 can use the steering angle information of the power steering device in addition to providing a dedicated steering angle sensor.

The control unit 12 includes an image conversion unit 13, an expected trajectory drawing unit 14, a white line detection unit 15, and a parallel determination unit 16.
The image conversion unit 13 extracts the horizontal edges E ₁ and E ₂ of the white lines 3 and 4 (see FIG. 5) from the rear image G1 (see FIG. 4) captured by the imaging unit 9, and the overhead image G2 (see FIG. 7). See). The rear image G1 is an image in which the white lines 3 and 4 are bent. The bird's-eye view image G2 is an image obtained by correcting the distortion of the rear image G1 so that the white lines 3 and 4 are straight lines and looking down from above, and further displaying the vehicle outline V (see FIG. 7). The predicted trajectory drawing means 14 calculates the expected trajectory L of the vehicle 7 based on the steering angle θs detected by the steering angle detecting means 11 and draws the expected trajectory L on the image displayed by the display means 10 ( (See FIG. 7).
The white line detection means 15 detects the white lines 3 and 4 on the left and right of the parking frame 2 from the overhead image G2 converted by the image conversion means 13. The parallel determination unit 16 determines whether or not the vehicle 7 is parallel to the left and right white lines 3 and 4 of the parking frame 2 detected by the white line detection unit 15.

As shown in FIG. 6, the white line detection by the white line detection means 15 is performed by extracting the horizontal edges E ₁ and E ₂ by Hough transform (Hough transform) and converting the coordinate values (x , Y)
ρ = x ^* sin (θ) + y ^* cos (θ)
The value of ρ is calculated from θmin to θmax and is voted on the ρ-θ space.
The left and right white lines 3 and 4 are the places with the highest voting score (ρ ₁ , θ ₁ ) and the places with the second highest vote (ρ ₂ , θ ₂ ), respectively.
Then, an average value (θ ₁ + θ ₂ ) / 2 of θ ₁ and θ ₂ is set as an angle of the white lines 3 and 4 with respect to the vehicle 7.
After the white line is detected by the Hough transform, the parallel determination unit 16 determines whether the angle of the white lines 3 and 4 with respect to the vehicle 7 is within a certain range, and whether or not the vehicle 7 is parallel to the white lines 3 and 4. to decide.

  When the parallel determination unit 16 determines that the vehicle 7 is parallel to the left and right white lines 3 and 4 of the parking frame 2, the predicted track drawing unit 14 displays the predicted track L on the image displayed by the display unit 10. Is not drawn (see FIG. 8).

Further, the control means 12 includes a steering guide means 17. When the predicted trajectory drawing means 14 does not draw the expected trajectory L, the steering guide means 17 displays the state of the steering angle θs detected by the steering angle detection means 11 as a steering guide image G3 (see FIG. 8). Further, the steering guide means 17 performs steering in which the wheel steered on the basis of the steering angle θs detected by the steering angle detection means 11 is parallel to the vehicle body when the expected locus drawing means 14 does not draw the expected locus L. The direction Rs is displayed by the steering guidance image G3 (see FIG. 9).
The steering guidance image G3 is an image of the steering S tilted by the current steering angle θs detected by the steering angle detection means 11 as the state of the steering angle θs, and the wheel is parallel to the vehicle body as the steering direction Rs. Therefore, an image such as an arrow indicating which direction the steering wheel S should be rotated can be obtained.

The control of the first embodiment in which the parking assist device 8 displays / hides the predicted locus L when the vehicle 7 is retracted and parked in the parking frame 2 will be described based on the flowchart of FIG.
As shown in FIG. 2, when the program starts (A01), the control means 12 first takes in the rear image G1 from the imaging means 9 (A02), and the horizontal edges E ₁ and E of the white lines 3 and 4 of the rear image G1. ₂ is extracted (A03), the edge image is converted into the overhead image G2 (A04), the white lines 3 and 4 are detected from the overhead image G2, and the position and angle of the white lines 3 and 4 are detected by the Hough transform. It is calculated (A05), and it is determined whether the vehicle 7 and the white lines 3 and 4 are parallel (A06).
When this determination (A06) is NO, the angle calculated in the above (A05) is outside a certain range, and the vehicle 7 is not parallel to the white lines 3 and 4, as shown in FIG. The predicted trajectory L of the vehicle 7 calculated by the predicted trajectory drawing means 14 is displayed on the image (A07), and the process returns to the capture of the rear image G1 (A02).
When this determination (A06) is YES, the angle calculated in the above (A05) is within a certain range, and the vehicle 7 is parallel to the white lines 3 and 4, as shown in FIG. The predicted trajectory L of the vehicle 7 calculated by the predicted trajectory drawing means 14 is not displayed in the displayed image (A08), the steering guide image G3 of the steering angle θs and the steering direction Rs is displayed as a steering guide (A09), and the rear The process returns to the capturing of the image G1 (A02).

Thus, the parking assist device 8 does not display the expected locus L when the vehicle 7 and the white lines 3 and 4 on the left and right of the parking frame 2 are parallel to each other, so the vehicle is curved with respect to the driver who intends to go straight ahead and backward. The expected trajectory L is not displayed, and the driver can be prevented from feeling uncomfortable.
Further, the control means 12 includes a steering guide means 17 for displaying the state of the steering angle θs detected by the steering angle detection means 11 when the expected locus drawing means 14 does not draw the expected locus L.
Thereby, the parking assistance device 8 can present the steering operation to the driver in an easy-to-understand manner by displaying the steering angle θs of the current steering wheel S when the predicted locus L is not displayed.
Further, the steering guide means 17 determines the steering direction Rs in which the wheels are parallel to the vehicle body based on the steering angle θs detected by the steering angle detection means 11 when the expected locus drawing means 14 does not draw the expected locus L. indicate.
Thereby, the parking assistance apparatus 8 displays the return direction (steering direction Rs) of the steering wheel S in which the wheels are parallel to the vehicle body, together with the current steering angle θs of the steering wheel S, when the predicted locus L is not displayed. As a result, the steering operation can be presented to the driver more easily.

10 to 15 show Embodiment 2 of the present invention. In the second embodiment, portions having the same functions as those of the first embodiment will be described with the same reference numerals.
As shown in FIG. 3, the parking assist device 8 according to the second embodiment supports driving when the vehicle 7 is parked in the white lines 3 and 4 and the wheel stops 5 and 6 that define the parking frame 2 of the parking lot 1. . As shown in FIG. 10, the parking assist device 8 includes an imaging unit 9, a display unit 10, a steering angle detection unit 11, and a control unit 12. The control unit 12 includes an image conversion unit 13, an anticipation unit, and a prediction unit. A trajectory drawing unit 14, a white line detection unit 15, a parallel determination unit 16, and a steering guide unit 17 are provided. Since each of these means 9-17 functions as described in the first embodiment, the description thereof is omitted (see FIGS. 3-9).
The control unit 12 according to the second embodiment further includes a white line end point detection unit 18 and a distance determination unit 19. The white line end point detection means 18 detects the white line end points 3a and 4a (see FIG. 3) of the left and right white lines 3 and 4 detected by the white line detection means 15. The distance determination means 19 determines whether the distance between the white line end points 3a and 4a and the vehicle rear end 7e (see FIG. 3) is equal to or less than a preset value. The predicted trajectory drawing unit 14 determines that the vehicle 7 is parallel to the left and right white lines 3 and 4 of the parking frame 2 by the parallel determination unit 16 and detects the white line detected by the white line end point detection unit 18. When the distance between the end points 3a and 4a and the vehicle rear end 7e of the vehicle 7 is equal to or less than a preset value, the expected locus L is not drawn.

In the detection of the white line end points 3a and 4a by the white line end point detecting means 18, as shown in FIG. 12, ρ ₁ and ρ ₂ are set to x coordinate values where the left and right white lines 3 and 4 are present, and a certain size (range). The left and right windows W ₁ and W ₂ are set.
On the set left and right windows W ₁ and W ₂ , as shown in FIG. 13, the small areas areaU and areaD are set with the y coordinate value y _i interposed therebetween, and the number of points in each of the small areas areaU and areaD is counted. (SumU · sumD) and the difference value dif_y _i is obtained (dif_y _i = sumD−sumU).
The obtained difference values dif_y _i of the left and right windows W ₁ and W ₂ are added, and as shown in FIG. 14, the y coordinate value of the value y _peak (maximum difference value) having the largest added difference value dif_y _i is Detected as white line end points 3a and 4a.
As shown in FIG. 3, the white line end points 3a and 4a on the side (front side) on which the vehicle 7 enters and the side where the wheel stops 5 and 6 are provided (rear side) Side) white line end points 3b and 4b. Since the white line end points are used to determine how close the vehicle 7 is to the parking frame 2, the white line end points 3a and 4a existing on the side (front side) on which the vehicle 7 enters are used as the white line end points for distance determination.

In the determination of the distance between the white line end points 3a and 4a and the vehicle rear end 7e by the distance determination means 19, the position y _body of the vehicle rear end 7e is set in advance. This value is determined in advance depending on the model of the vehicle 7, the installation position of the imaging means 9, and the like. If the distance between the detected white line end point y _peak and the vehicle rear end y _body is equal to or less than the threshold th (y _body −y _peak ≦ th), the predicted locus L is not displayed. The value of the threshold th is determined empirically.

The control of Example 2 in which the parking assist device 8 displays / hides the predicted locus L when the vehicle 7 is retracted and parked in the parking frame 2 will be described based on the flowchart of FIG. 11.
As shown in FIG. 11, when the program starts (B01), the control means 12 first takes in the rear image G1 (see FIG. 4) from the image pickup means 9 (B02), and next to the white lines 3 and 4 of the rear image G1. Edges E ₁ and E ₂ are extracted (B03), the edge image is converted into an overhead image G2 (see FIG. 7) (B04), and white lines 3 and 4 are detected from the overhead image G2 (see FIG. 6). At the same time, the position and angle of the white lines 3 and 4 are calculated by the Hough transform (B05), and it is determined whether the vehicle 7 and the white lines 3 and 4 are parallel (B06).
When this determination (B06) is NO, the angle calculated in the above (B05) is out of a certain range, and the vehicle 7 is not parallel to the white lines 3 and 4, as shown in FIG. The predicted trajectory L of the vehicle 5 calculated by the predicted trajectory drawing means 14 is displayed on the image (B07), and the process returns to the capture of the rear image G1 (B02).
If this determination (B06) is YES, the angle calculated in (B05) is within a certain range, and the vehicle 7 is parallel to the white lines 3 and 4, the white line end points on the front side of the left and right white lines 3 and 4 3a and 4a are detected (see FIGS. 12 to 14) (B08), and it is determined whether the distance between the white line end points 3a and 4a and the vehicle rear end 7e is equal to or smaller than a preset value (see FIG. 15) (see FIG. 15). B09).
When this determination (B09) is NO and the vehicle 7 is away from the white line end points 3a and 4a, the vehicle calculated by the expected locus drawing means 14 on the image displayed by the display means 10 as shown in FIG. 7 is displayed (B07), and the process returns to the capture of the rear image G1 (B02).
If this determination (B09) is YES and the vehicle 7 is approaching the white line end points 3a and 4a, the vehicle calculated by the predicted locus drawing means 14 on the image displayed by the display means 10 as shown in FIG. 7 is not displayed (B10), the steering guide image G3 (see FIG. 9) of the steering angle θs and the steering direction Rs is displayed as a steering guide (B11), and the process returns to the capture of the rear image G1 (B02). .

Thus, the parking assist device 8 does not display the expected locus L when the vehicle 7 and the white lines 3 and 4 on the left and right of the parking frame 2 are parallel to each other, so the vehicle is curved with respect to the driver who intends to go straight ahead and backward. The expected trajectory L is not displayed, and the driver can be prevented from feeling uncomfortable.
Further, the parking assist device 8 can present the steering operation to the driver in an easy-to-understand manner by displaying the steering angle θs of the current steering when the predicted locus L is not displayed.
Furthermore, the parking assist device 8 displays the steering return direction (steering direction Rs) in which the wheels are parallel to the vehicle body together with the steering angle θs of the current steering when the predicted locus L is not displayed. It is possible to present the steering operation more easily.
The parking assist device 8 satisfies the condition that the vehicle 7 and the parking frame 2 are close to each other in addition to the condition that the vehicle 7 and the left and right white lines 3 and 4 of the parking frame 2 are parallel to each other. Since the expected trajectory L is not sometimes displayed, it is possible to further display according to the driver's intention.

  The parking assist device of the present invention can provide an appropriate image to the driver at the time of a parking driving operation in which the vehicle is parked in the parking frame, and can be applied to various vehicles.

DESCRIPTION OF SYMBOLS 1 Parking lot 2 Parking frame 3 Right white line 4 Left white line 5 Right wheel stopper 6 Left wheel stopper 7 Vehicle 8 Parking assistance device 9 Imaging means 10 Display means 11 Steering angle detection means 12 Control means 13 Image conversion means 14 Prediction Trajectory drawing means 15 White line detection means 16 Parallel determination means 17 Steering guide means 18 White line end point detection means 19 Distance determination means

Claims (4)

Imaging means for imaging the rear of the vehicle;
Display means for displaying an image captured by the imaging means;
Steering angle detection means for detecting the steering angle of the vehicle;
A parking assistance device comprising: an expected trajectory drawing unit that calculates an expected trajectory of the vehicle based on the steering angle detected by the steering angle detection unit and draws the image on the image displayed by the display unit;
Image conversion means for converting a rear image captured by the imaging means into an overhead image;
White line detection means for detecting left and right white lines of the parking frame from the overhead image converted by the image conversion means;
Parallel determination means for determining whether or not the vehicle is parallel to the left and right white lines of the parking frame detected by the white line detection means,
The expected locus drawing means includes:
A parking assist device, wherein when the parallel determination means determines that the vehicle is parallel to the white lines on the left and right of the parking frame, an expected trajectory is not drawn. White line end point detecting means for detecting white line end points of the left and right white lines detected by the white line detecting means;
The expected locus drawing means includes:
The parallel determination means determines that the vehicle is parallel to the left and right white lines of the parking frame, and the distance between the white line end point detected by the white line end point detection means and the vehicle rear end is equal to or less than a preset value. The parking assist device according to claim 1, wherein the predicted locus is not drawn when   The steering guidance means for displaying the state of the steering angle detected by the steering angle detection means when the expected trajectory drawing means does not draw the expected trajectory. Parking assistance device. The steering guide means is
4. The steering direction in which the wheels are parallel to the vehicle body is displayed based on the steering angle detected by the steering angle detecting means when the predicted locus drawing means does not draw the expected locus. The parking assistance device described.

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