JP6281435B2 - Parking assistance system - Google Patents

Description

  The present invention relates to a parking assistance system capable of switching and displaying from a rear image to an overhead image.

  In the parking support system that converts the video of the back camera (rear image) attached to the rear of the vehicle into a bird's-eye view image from the virtual viewpoint installed in the sky above the vehicle, the parking frame is obtained from the image data acquired by the back camera. A parking support system that detects and automatically switches a display image to a bird's-eye view image from the positional relationship between the host vehicle and the parking frame has been developed (see Patent Document 1).

  For example, when the vehicle 31 shown in FIG. 3E is parked backward, first, a wide-angle rear image 20 is displayed as shown in FIG. 3A, and then image processing is performed as shown in FIG. When the angle between the parking frame 6 and the marker 30 detected by the above is less than the threshold value and the distance to the rear end 6b of the parking frame 6 is less than the threshold value, it is determined that the vehicle has entered the parking frame 6. As shown in FIGS. 3C and 3D, the display is automatically switched to the bird's-eye view image 21 so that the distance between the vehicle (31 ″) and the wheel stopper 7 or the rear can be easily grasped.

  By the way, in such a parking assistance system, if the shift position is in the reverse range and the distance to the rear end 6b of the parking frame 6 is within a certain range, the display is switched to the bird's-eye view image 21 and is shown in FIG. When the vehicle starts to move backward after forward parking, the display is switched to the overhead image 21 by detecting the front end 6a of the parking frame 6 in spite of the situation where the wide-angle rear image 20 should be displayed. There was a problem.

  On the other hand, in Patent Document 2, it is possible to automatically determine whether or not the vehicle is moving backward after forward parking by using shift position, vehicle speed, and parking brake transition information, and to control display screen selection and switching timing. It is disclosed. For example, as shown in FIG. 5 (a), when the vehicle 41 moves in the drive range D, shifts to the parking range P, and then moves in the reverse range R, the backward information after forward parking is obtained from the transition information. It is determined that the vehicle is starting. However, only by shifting information of the shift position, vehicle speed, and parking brake, the direction change as indicated by reference numerals 42 and 42 'in FIG. 5B, or as indicated by reference numerals 43 and 43' in FIG. 5C. Indistinguishable from turning back when reversing parking.

  Patent Document 3 discloses that information on the elapsed time from the door opening / closing operation and the elapsed time from the seat belt wearing operation is used for the determination. However, even if the time from the event timing is taken into account, for example, It is indistinguishable from stopping in the middle of turning or turning around, helping to put in and out of luggage and raising and lowering passengers, and then boarding again and resuming parking.

JP 2011-126433 A JP 2005-112267 A JP 2008-195263 A

  The present invention has been made in view of the above circumstances, and its purpose is to prevent a bird's-eye view image from being displayed when the vehicle starts to reverse after forward parking, and to prevent the overhead view image from being displayed. It is to provide a parking assistance system that can display a rear image with certainty.

In order to solve the above-mentioned problem, the parking support system according to the present invention includes:
Imaging means (2) for imaging the rear of the vehicle, image processing means (10) for synthesizing the overhead image (21) from the rear image (20) captured by the imaging means, and the rear image when the vehicle is moving backward Or image display means (3) for displaying the overhead image,
When the image processing means (10) detects the parking frame (6) from the rear image or the overhead image, the display of the image display means is displayed when the vehicle enters the parking frame. Can be switched to the overhead image (21) from
Whether the front end (6a) of the parking frame (6) is located within the predetermined range (60) in the image captured during the forward parking when a backward movement is detected after the vehicle has parked forward in the parking frame. If it is determined whether or not it is within a predetermined range, switching to the bird's-eye view image is prohibited.

The parking assistance system according to the present invention has the following effects by the above configuration.
By turning off the automatic switching function to the bird's-eye view image when the vehicle starts moving backward after forward parking, it is possible to continue displaying a wide-field rear image regardless of the presence or absence of a parking frame. In addition, by determining whether or not the front end of the parking frame is located within a predetermined range during forward parking, the vehicle parking mode can be reliably determined, and there is no misconception as turning back or turning during reverse parking. Therefore, the automatic switching function to the bird's-eye view screen can be turned on except for the reverse start, and the automatic switching at the final stage during reverse parking is not hindered.

  In the present invention, the predetermined range is given as a sum of a free running distance obtained by multiplying the approach speed to the parking frame recorded during forward parking by a brake reaction time, and a braking distance obtained by multiplying the approach speed by a braking time. In the aspect configured to be set or calibrated based on the stopping distance, the detection range is set or calibrated to reflect the actual parking situation, so that the fluctuation factors due to the driver and the driving situation are taken into consideration. Judgment with high accuracy can be performed.

  In the present invention, in the aspect in which the predetermined range is set or calibrated based on parking frame data acquired by the image processing means, the detection range is set to reflect an actual driving environment. Alternatively, since calibration is performed, it is possible to make a highly accurate determination in consideration of a variation factor caused by the driving environment.

  In a preferred aspect of the present invention, the predetermined range is set in a range of 1.6 m to 2 m behind the vehicle. By setting in advance in consideration of the size of the vehicle and the size of a general parking frame, the system can be simplified while ensuring the detection accuracy.

It is a block diagram which shows the parking assistance system which concerns on this invention embodiment. It is a side view which shows the vehicle provided with the parking assistance system. (A)-(d) is a display image of the parking assistance system used as the premise of this invention, (e) is a top view which shows reverse parking condition. (A) is a top view which shows the reverse start after a forward parking, (b) is a schematic diagram which shows the display image before this invention implementation. (A) is the reverse start after forward parking, (b) is a direction change, (c) is a top view which shows the return at the time of reverse parking. It is a typical bird's-eye view image which shows the detection range of a parking frame edge part. (A) is a top view which shows the reverse start after forward parking, (b) is a schematic diagram which shows the display image in this invention. It is a flowchart which shows the operation | movement at the time of the vehicle stop of the parking assistance system which concerns on this invention embodiment. It is a flowchart which shows the operation | movement at the time of vehicle start of the parking assistance system which concerns on this invention embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a block diagram showing a parking assistance system according to the present invention, and FIG. 2 is a side view showing a vehicle equipped with the parking assistance system. In each figure, the parking support system of the present invention is a virtual camera 2 ′ in which a rear camera 2 as an imaging means attached to the rear of the vehicle 1 and a rear image 20 acquired by the rear camera 2 are installed above the rear of the vehicle. The image processing apparatus 10 as an image processing means including a process of converting to the bird's-eye view image 21 and the display apparatus 3 for displaying an image output from the image processing apparatus 10 are mainly configured.

  The back camera 2 is preferably a digital camera using a solid-state imaging device and a wide-angle lens, and can capture a wide range of rear images 20 including the ground surface 5 from the rear bumper 4. The display device 3 is an image display monitor installed on the instrument panel, and is shared with the monitor of the car navigation system. Basically, the image of the display device 3 is rearward when the shift position is shifted to the reverse range. The image 20 or the overhead image 21 is switched.

  The image processing apparatus 10 includes a vehicle information recording unit 17 that records vehicle information such as a vehicle speed, a steering angle, a yaw rate, and a shift position, a video recording unit 11 that receives and records a rear image 20 from the back camera 2, and a recording. Parking frame detection means 14 for detecting the parking frame 6 from the rear image 20, the angle between the vehicle 1 and the parking frame 6, the angle / rear end / front end detection means 15 for detecting the rear end 6b or the front end 6a of the parking frame, vehicle information And a parking mode determination means 16 for determining whether the parking operation is reverse parking or forward parking, an image switching means 12 for switching a display image according to the parking mode, and a video output means 13 for outputting a video to the display device 3. ing.

  The video recording means 11 includes an image input memory (VRAM) that stores image data of the rear image 20 sent from the back camera 2 in units of frames. The image data is sent to an image processor (CPU) for image processing. The distortion aberration is corrected and coordinate conversion is performed according to the program, and the resultant is synthesized with the overhead image 21. Furthermore, the parking frame 6 is detected by the following procedure by the parking frame detection means 14 and the angle / rear end / front end detection means 15 implemented as part of the image processing program, and the positional relationship with the vehicle 1 is specified. The

  First, the parking frame detection means 14 detects the parking frame 6 as parallel linear components by edge extraction and Hough transform of image data. That is, each edge-extracted pixel is voted in the parameter space, and the linear component is detected by extracting the local maximum value of the voting frequency in the parameter space. Of these, it is a parallel linear component and is actually extracted as an edge. The part which is present is specified as the parking frame 6.

  Next, the angle / rear end / front end detection means 15 detects the angle of the detected parking frame 6 and the vehicle 1 on the ground surface, and is substantially parallel when the angle is equal to or less than a threshold value. The distance between the left and right ends of the parking frame 6 and the vehicle 1 is measured on the image, and it is detected whether the left and right ends are within a predetermined range.

  For example, when the shift position is in the reverse range and the parking frame 6 and the host vehicle (marker 30) are parallel as shown by reference numeral 31 'in FIG. If the distance between the rear end 6b of the parking frame 6 and the vehicle 1 (31 ″) is equal to or smaller than a threshold value in the forward direction of travel on the upper side of the image, the display image of the display device 3 is displayed. Is automatically switched to the overhead image 21 shown in FIG.

  As described above, when the vehicle is reversely parked, the display is switched to the bird's-eye view image 21 so that the distance between the vehicle (31 ″) and the wheel stopper 7 or the rear can be easily grasped as shown in FIG. However, when the vehicle starts to move backward after forward parking, it must be avoided that the display is switched to the overhead image 21 by detecting the front end 6a of the parking frame 6 as shown in FIG. Therefore, in the parking assistance system according to the present invention, the parking mode determination unit 16 and the image switching unit 12 are mounted in the image processing apparatus 10 as part of the image processing program.

  The parking mode determination means 16 is also used when the vehicle stops immediately before the angle / rear end / front end detection means 15 when the end of the parking frame 6 (front end 6a or rear end 6b) is detected within a predetermined range. By referring to the recorded parking mode (flag), it is discriminated whether it is reverse parking or forward parking (reverse start after forward parking), and automatic switching of the image switching means 12 is turned on / off according to the discrimination.

The parking mode determination means 16 determines the parking mode when the vehicle 1 stops, sets four flags as described below according to the parking mode, and stores them until the next start.
Flag 1: Reverse parking and parking frame rear end 6b is outside predetermined range Flag 2: Reverse parking and parking frame rear end 6b is within predetermined range Flag 3: Forward parking and parking frame front end 6a is out of predetermined range Flag 4: Forward parking and Parking frame front edge 6a is within specified range

  Of course, the rear end 6b of the parking frame 6 may be reflected in the back camera 2 in the case of reverse parking, and the front end of the parking frame 6 may be reflected in the back camera 2 in the case of forward parking. Therefore, if the reverse parking or the forward parking is determined from the shift position at the time of stopping, it is determined whether the end of the parking frame 6 that can be reflected in the back camera 2 is the front end 6a or the rear end 6b.

  FIG. 6 shows a range 60 in which the position of the end (front end 6a or rear end 6b) of the parking frame 6 is determined. This range 60 is a range (movement distance) in which the automatic switching to the bird's-eye view image 21 is prohibited and the rear image 20 is displayed when the vehicle 1 starts moving backward from the parking frame 6.

  Therefore, it is set based on the stop distance given as the sum of the free running distance obtained by multiplying the approach speed to the parking frame 6 by the driver's brake reaction time and the braking distance obtained by multiplying the approach speed by the braking time. For example, assuming that the vehicle speed during a general parking operation is 1.4 m / s (5 km / h), and the time during which the driver can stop safely in consideration of the brake reaction time and braking time of the driver is 1.2 sec, the range 60 Becomes 1.7 m.

  On the other hand, you may set to the value which pulled the full length of the own vehicle from 5m which is the length of a general parking frame. For example, in the case of a light vehicle, the maximum length is 3.4 m, so the range 60 is 1.6 m. Further, if the front end 6a of the parking frame 6 deviates from the field of view of the back camera 2, it will no longer be switched to the bird's-eye view image 21, so it is not necessary to set the range 60 unnecessarily wide. Even if you start moving backward from a certain parking space and park backward in the parking space on the opposite side, if you keep the maximum distance of 2 m in consideration of the width of the traveling section between them, Automatic switching function can be used.

  Next, the operation of the parking assistance system based on the above embodiment when the vehicle is stopped will be described with reference to FIG.

  First, when an operation flow is started while the vehicle is running, vehicle information such as vehicle speed, steering angle, yaw rate, shift position, etc. is recorded in the vehicle information recording means 17 and is overwritten and updated after a predetermined time. The recording time may be very short, and the recording may be interrupted when the vehicle speed is above a certain level.

  Regardless of the advancing direction (shift position), an image behind the vehicle taken by the back camera 2 is recorded in the video recording means 11 and is overwritten and updated after a predetermined time. As described above, the recording time may be very short, and the recording may be interrupted when the vehicle speed is above a certain level.

  When the parking frame 6 is detected in the image data acquired by the back camera 2 and the parking frame 6 is detected, the angle between the vehicle 1 and the parking frame 6 and the end position of the parking frame 6 (rear end 6b or Calculate the leading edge 6a) and record the result.

  When the vehicle 1 has not entered the parking frame 6, the vehicle information acquisition, the back camera recording, and the parking frame detection are continued. At this time, if the shift position is in the reverse range, the current position information and the target position of the vehicle 1 are presented on the display device 3.

  If it is determined that the vehicle 1 has entered the parking frame 6, the process proceeds to the next vehicle speed determination. If the vehicle speed is greater than 0, it is determined that the vehicle 1 has not yet stopped, Continue acquisition, back camera recording, and parking frame detection.

  If the vehicle speed is detected as 0, it is determined that the host vehicle has stopped, the next shift position is determined, and whether the shift position when the vehicle is stopped is in the reverse range (R) or not (drive range (D)). Determine.

  When the shift position is in the reverse range (R), it is determined that the vehicle is reversely parked, and when the end (rear end 6b) of the parking frame 6 is not within the range 60, the flag 1 is set. If the end (rear end 6 b) of the parking frame 6 is within the range 60, the flag 2 is set.

  When the shift position is in the drive range (D), it is determined that the parking is forward, and when the end of the parking frame 6 (front end 6a) is not within the range 60, the flag 3 is set. If the end (front end 6a) of the parking frame 6 is within the range 60, the flag 4 is set.

  Finally, the flag value corresponding to the parking mode is stored and saved, and the process ends.

  Next, the operation of the parking assistance system when the vehicle starts will be described with reference to FIG.

  When the vehicle starts, vehicle information such as the shift position is first acquired. If the shift position is not in the reverse range (R) (in the case of flags 1 and 2), it is determined that the vehicle is moving forward, The video output is stopped, and a navigation screen, a front camera screen, and the like are displayed on the display device 3.

  If the shift position is in the reverse range (R), it is determined that the vehicle is moving backward, and the parking mode determination flag recorded in the vehicle information recording means 17 is confirmed.

  When the value of the parking mode determination flag is 4, when the video from the back camera 2 is displayed, the automatic switching function of the image switching means 12 is turned off, the switching to the overhead image 21 is prohibited, and the rear image 21 is displayed. Display. At this time, the parking frame 6 and its front end 6a are detected by the rear camera 2 of the vehicle 1 when starting backward, but the automatic switching function is turned off in advance, so as shown in FIG. 7B. A wide-angle rear image 20 is displayed from the time of departure from the reverse side. Further, after the reverse departure, as shown in FIG. 7A, if the parking frame 6 and the front end 6a thereof are out of the field of view of the back camera 2, the image is no longer switched to the bird's-eye view image 21, and thereafter the image is switched. The automatic switching function of the means 12 is turned on.

  On the other hand, when the value of the parking mode determination flag is other than 4, the automatic switching function of the image switching unit 12 is turned on, and the video (rear image 20) from the back camera 2 is displayed. In this case, since parking was outside the parking frame 6 or out of the parking frame 6, even if the end of the parking frame 6 is detected, the end is not detected in most cases, and the rear image 20 is displayed. For example, when moving to another parking frame located on the opposite side and parking, the rear image 6 is automatically switched to the overhead image 21 as soon as the rear end 6b of the parking frame is detected. .

  As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment, Based on the technical idea of this invention, various deformation | transformation and a change are further possible.

  For example, in the above-described embodiment, the range 60 for determining the position of the end portion (front end 6a or rear end 6b) of the parking frame 6 has been preset as a fixed value, but vehicle information during actual forward parking is shown. Based on the approach speed to the parking frame 6 recorded in the recording means 17, a stop distance given as the sum of the free running distance and the braking distance is calculated, and a range 60 is set based on the stop distance, or a preset fixed It can also be configured so that the values are updated or calibrated.

  Further, the range 60 may be set based on the data of the parking frame 6 actually acquired by the image processing means 10, or a preset fixed value may be updated or calibrated.

1, 31, 41, 42, 43 Vehicle 2 Back camera (imaging means)
2 'virtual viewpoint 3 display device 4 rear bumper 5 ground surface 6 parking frame 6a front end 6b rear end 10 image processing device 11 video recording means 12 image switching means 13 video output means 14 parking frame detection means 15 angle / rear end / front end detection Means 16 Parking mode determination means 17 Vehicle information recording means 20 Rear image 21 Overhead image 30 Marker 60 Range

Claims (4)

Imaging means for imaging the rear of the vehicle, image processing means for synthesizing an overhead image from a rear image captured by the imaging means, and an image display means for displaying the rear image or the overhead image when the vehicle moves backward, With
A parking frame is detected from the rear image or the overhead image by the image processing means, and the display of the image display means can be switched from the rear image to the overhead image when the vehicle enters the parking frame. In the parking assistance system,
When a backward movement is detected after the vehicle has parked forward in the parking frame, it is determined whether or not a front end of the parking frame is located within a predetermined range from an image captured during the forward parking, and the predetermined range A parking assistance system configured to prohibit switching to the overhead image when located inside.   The predetermined range is based on a stop distance given as a sum of a free running distance obtained by multiplying the approach speed to the parking frame recorded at the time of forward parking by a brake reaction time and a braking distance obtained by multiplying the approach speed by a braking time. The parking support system according to claim 1, wherein the parking support system is configured to be set as follows.   The parking support system according to claim 1, wherein the predetermined range is set or calibrated based on parking frame data acquired by the image processing means.   The parking support system according to claim 1, wherein the predetermined range is set in a range of 1.6 m to 2 m behind the vehicle.

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