JP2009139324A - Travel road surface detecting apparatus for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a travel road surface detecting apparatus for vehicles capable of accurately detecting road surfaces by simple processing. <P>SOLUTION: The travel road surface detection apparatus for vehicles for detecting a road slope in a prescribed wide road surface region on the basis of road surface images acquired by imaging travel road surfaces includes a first imaging means; a second imaging means; a specific region setting means for setting a specific region separated from a vehicle on an imaged road surface by a prescribed distance as a specific region; a specific plane constant computing means for detecting corresponding points retrieved from road surface images imaged by the first imaging means and the second imaging means in the specific region and computing plane constants which specify a specific plane by projection transformation; and a travel road surface setting means for combining the specific region with at least one specific region set in the past before the specific region after a lapse of a prescribed time depending on the amount of movement of the vehicle during the prescribed time and setting it as a travel road surface. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vehicular traveling road surface detection device, and more particularly to a vehicular traveling road surface detection device that detects a road surface inclination in a predetermined wide road surface region from a road surface image obtained by imaging the traveling road surface.

Conventionally, as shown in Patent Document 1, a plane detection device that converts a reference image obtained by a stereo camera to the other camera viewpoint and calculates a plane parameter of a traveling road surface from the converted image with the other camera image is provided. Are known.
Further, as shown in Patent Document 2, a method for detecting the gradient of a road ahead is known that can detect the slope angle of the road ahead.

JP 2006-053754 A JP 09-325026 A

  However, in the apparatus or method as described above, the burden of the arithmetic processing is very large, and in particular, there are cases where the road surface having a plurality of inclination changes cannot be processed. In addition, a simple change in the gradient between two planes, for example, can be obtained, but when there are various changes in the inclination, the distance to the road surface and the inclination cannot be detected accurately.

  Accordingly, the present invention has been made to solve the above-described problems of the prior art, and an object thereof is to provide a vehicle road surface detection device that can accurately detect a road surface by simple processing. Yes.

  In order to achieve the above object, a vehicle road surface detection device according to the present invention is a vehicle road surface detection device for detecting a road surface inclination in a predetermined wide road surface region from a road surface image obtained by imaging the road surface. First imaging means for imaging the vehicle, second imaging means for imaging the traveling road surface so as to obtain a road surface image that overlaps at least a part of the road surface image captured by the first imaging means, and the captured road surface Specific area setting means for setting a specific area that is a predetermined distance away from the vehicle as a specific area, and each of the specific areas searched for in each road image imaged by the first imaging means and the second imaging means A specific plane constant calculating means for detecting a corresponding point and calculating a plane constant for defining a specific plane by projective transformation; a specific area; and a predetermined area before the specific area It is characterized by having a traveling road surface setting means for setting at least one specific region is set in the past, as road surface bonded to in accordance with the amount of movement of the vehicle at a given time, the.

  In the present invention configured as described above, a specific area that is a predetermined distance away from the vehicle on the imaged road surface is set as the specific area, a plane constant is calculated in the specific area, and the specific area and after a predetermined time are calculated. At least one specific area set in the past before this specific area is combined according to the amount of movement of the vehicle in a predetermined time, and set as a traveling road surface. Therefore, for example, the road gradient from the specific area to immediately before the vehicle can be detected only by image processing of the specific area such as several tens of meters ahead, and the processing load can be reduced. In addition, since the specific area and at least one specific area set in the past before this specific area after a predetermined time are combined according to the amount of movement of the vehicle in the predetermined time and set as the road surface, the road surface gradient Detection is also accurate.

In the present invention, preferably, the moving amount of the vehicle is determined based on the positional relationship of a predetermined stationary object in the captured image.
In the present invention configured as described above, the amount of movement of the vehicle can be determined by highly accurate position correction using a stationary object, so that the road surface gradient can be detected with higher accuracy.

In the present invention, preferably, the moving amount of the vehicle is determined by performing an optical flow process on a predetermined stationary object in the captured image.
In the present invention configured as described above, the movement amount of the vehicle can be determined by the optical flow process, so that the road surface gradient can be detected with higher accuracy.

In the present invention, it is preferable that the specific area setting unit changes the predetermined distance according to the speed of the vehicle.
In the present invention configured as described above, a specific region suitable for vehicle control and image processing can be set according to the speed of the vehicle.

In the present invention, the plane constant is preferably defined by the distance d from the vehicle and the slope n.
In the present invention configured as described above, the distance and inclination of the specific area can be detected easily and accurately.

In the present invention, it is preferable that the traveling road surface setting means includes a specific area corresponding to the amount of movement of the vehicle and the past when the distance d is equal to or smaller than a predetermined value and / or the inclination n is equal to or larger than the predetermined value. Cancels the connection with a specific area.
In the present invention configured as described above, when the distance d is equal to or smaller than the predetermined value and / or the slope n is equal to or larger than the predetermined value, for example, when the vehicle cuts in front of the vehicle, the specific region corresponding to the moving amount of the vehicle And the past specific area are stopped, unnecessary processing can be stopped and the processing load can be reduced.

  According to the vehicular traveling road surface detection device of the present invention, the road surface can be accurately detected by simple processing.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
First, a vehicle to which a vehicle road surface detection device according to an embodiment of the present invention is applied, a basic flow of road area detection processing, an example of a processed image, and road area detection processing contents will be described. FIG. 1 is a conceptual diagram of a vehicle to which a vehicle road surface detection device according to an embodiment of the present invention is applied. FIG. 2 is a road area detection process used in the vehicle road surface detection device according to an embodiment of the present invention. FIG. 3 is a conceptual diagram showing an example of a processing image of road area detection processing used in the vehicle road surface detection device according to the embodiment of the present invention. FIG. 4 is a projective transformation. It is a figure which shows the example of each corresponding point of the left and right cameras used for. Hereinafter, S represents each step.

  The embodiment of the present invention does not calculate the distance from the host vehicle and the inclination of the surface of the entire road surface as in the past, but sets a predetermined specific area, for example, several tens of meters away, and the distance and inclination of the specific area. When the road surface changes every moment as the vehicle travels, information on the distance and inclination of the specific area is combined in time series to detect the gradient of the road surface before the specific plane including the specific plane. Is.

First, as shown in FIG. 1, the vehicle 1 includes a stereo camera 4 installed above the front window 2 and an ECU processing device 6.
As shown in FIG. 2, in the road area detection process, a stereo image is acquired by the stereo camera 4 in S1. Of the obtained images, one image is a reference image (FIG. 3A) and the other image is a reference image (FIG. 3B).
Next, in S2 of FIG. 2, as a pre-processing, the ECU 6 takes in these standard image and reference image, and performs contrast adjustment using a LOG filter or the like in order to match the luminance of both images.

  Next, as shown in S3 of FIG. 2, the reference image (FIG. 3B) is converted into an image viewed from the viewpoint of the standard image (FIG. 3A) using (1) projective transformation matrix calculation described later. Perform viewpoint conversion. In this process, the projective transformation matrix for the road plane is dynamically estimated, and the projective transformation image as shown in FIG. 3C is obtained by projective transformation of the reference image (FIG. 3B). According to the projective transformation image obtained in this way, an object with a height included in the reference image is tilted by the projective transformation, so that the reference image (FIG. 3C) after the projective transformation and the standard image (FIG. 3). By obtaining the difference from (a)), it is possible to extract a road plane portion having no height.

That is, first, in S4 of FIG. 2, as shown in FIG. 3D, a difference image in luminance values between the base image (FIG. 3A) and the reference image after projective transformation (FIG. 3C) is obtained. Next, an area where the luminance difference is equal to or less than the threshold value is obtained as shown by a black portion in FIG. Then, in S5 of FIG. 2, as shown in FIG. 3 (f), (2) the posture of the road plane in the road region as shown in gray can be calculated.
As will be described later, these processes can be performed for each specific plane obtained by dividing the road surface into a plurality of divided regions.

での輝度差の2乗を評価関数e(H)として、これを最小にする射影変換行列

を求める。算出式は以下のようになる。

ただし、

は画像iの同次座標で表した位置

での輝度値、Hは画像間の平面部に対応した射影変換行列とする。 Next, the road area detection process for obtaining the distance d from the vehicle to the specific plane and the attitude n of the specific plane performed in the vehicle road surface detection apparatus according to the embodiment of the present invention will be described in more detail.
1. (1) Projection transformation matrix calculation (S3 in FIG. 2)
(1) Projection transformation matrix calculation formula For the image obtained by transforming the reference image I _r with the projection transformation matrix H and the standard image I _b , within the plane region estimation range

Projection transformation matrix that minimizes the square of the luminance difference at と し て as the evaluation function e (H)

Ask for. The calculation formula is as follows.

However,

Is the position of image i in homogeneous coordinates

The luminance value at H and H is a projective transformation matrix corresponding to the plane portion between images.

(2) Projection transformation matrix calculation method A projection transformation matrix satisfying equation (1) is obtained by searching. The processing procedure is as follows.
(A) If there is a projective transformation matrix estimated at the previous time, it is set as an initial value. At the start of the plane extraction process, there is no projective transformation matrix at the previous time, so corresponding points as shown in FIG. 4 in the road plane (for example, specific on the road surface) A projection transformation matrix H ₀ obtained by setting a white line having luminance, a sign on the road surface, a manhole, etc.) and using the least square method is set as an initial value.

ただし、ステレオカメラ間の回転行列をR、ベースラインベクトルをt、平面法線ベクトルをｎ、カメラと平面間距離をd、基準カメラと参照カメラの内部パラメータをＡ₁、Ａ₂、定数項をkとする。定数項（k≠0）は、画像が得られた射影変換行列には定数倍の自由度が存在することを示す。 (B) A projective transformation matrix is calculated from the stereo camera image. Next, the projective transformation matrix is expressed by Equation (2). This singular value decomposition to determine the normal vector of the road plane, and calculates the normal vector n ₀ and the inner product calculated from the projective transformation matrix H _0, when found and plan area fit in a range of the projective transformation Judge that the matrix is correct. In other cases, the same calculation is performed using the next projective transformation matrix H ₁ as an initial value, assuming that an erroneous local minimum has occurred. If a correct projection transformation matrix is still not found, the same calculation is performed using the projection transformation matrix H ₂ as an initial value. However, projective transformation matrix H _1, H ₂ was determined from the normal vectors n _1, n ₂ and projective transformation matrix H ₀ for the planar normal vector n ₀ inclined 4 ° in the longitudinal pitch direction of the projective transformation matrix H ₀ It is obtained from the equation (2) using R, t, and d.

However, the rotation matrix between stereo cameras is R, the baseline vector is t, the plane normal vector is n, the distance between the camera and the plane is d, the internal parameters of the reference camera and the reference camera are A ₁ and A ₂ , and the constant terms are k. The constant term (k ≠ 0) indicates that the projective transformation matrix from which the image is obtained has a degree of freedom that is a constant multiple.

(C) If a correct projection transformation matrix cannot be obtained even if all projection transformation matrices (H ₀ , H ₁ , H ₂ ) are used, it is assumed that no plane exists in the image, and the projection transformation matrix and calculation are performed. The area is reset, and the process ends here and proceeds to the next process.

t/d、nは以下の関係式から求めることができる。

ただし、σ₁≠σ₂≠σ₃のとき、

（ε_1,3＝±1）・・・(5)

ε_1,3を決定するために、2台のカメラが道路面を向いており平面が見えているという条件を加える。すなわち、nと

との内積が正になる。これで、解が2つとなる。次に、それぞれのnについて、求まったtと、実際のカメラ配置の大まかな並進ベクトルである

との内積を計算し、1に近いほうのtをnの解とする。 2. (2) Road plane posture calculation (S5 in FIG. 3)
The orientation and position of the plane relative to the stereo camera are calculated from the projective transformation matrix for the plane between the stereo images by using singular value decomposition. If the camera internal parameters A ₁ and A _{2 in} Equation (2) are known, the projective transformation matrix H ′ can be decomposed into singular values as shown in Equation (3).

t / d and n can be obtained from the following relational expression.

However, when σ ₁ ≠ σ ₂ ≠ σ ₃

(Ε _1,3 = ± 1) (5)

In order to determine ε _1,3 , a condition is added that the two cameras are facing the road and the plane is visible. I.e. n and

The inner product with becomes positive. This gives two solutions. Next, for each n, the calculated t and the approximate translation vector of the actual camera placement

The t product closer to 1 is taken as the solution of n.

以上のようにして、特定平面の平面定数として、車両１から特定平面までの距離ｄ及び特定平面の姿勢（傾き／法線ベクトル）ｎを求めることが出来る。 Next, d can be obtained from the obtained absolute value of t / d and the baseline length | t |

As described above, the distance d from the vehicle 1 to the specific plane and the attitude (inclination / normal vector) n of the specific plane can be obtained as the plane constant of the specific plane.

Next, the concept of processing of the vehicle road surface detection device according to the embodiment of the present invention will be described with reference to FIGS.
FIG. 5 is a conceptual diagram showing a specific area where image processing is set ahead of the traveling direction of the vehicle. FIG. 6 shows a specific area (FIG. 6A) as shown in FIG. The conceptual diagram for demonstrating the road surface where the plane constant was determined by the specific area | region (B, C, D) (FIG.6 (b), (c), (d)) set in the past which moved toward FIG. 7 shows the positions (a, c, e) of the specific areas in which the plane constants are determined a predetermined time before, and the positions (b) where the positions of the past specific areas are corrected to the current positions. , D, f) and the current position (g) of the specific region.

  First, as shown in FIG. 5, in the embodiment of the present invention, a road surface of a predetermined area several tens of meters ahead in the traveling direction of the vehicle is determined as a specific area (specific plane), The plane constant (distance d, slope (normal vector) n) of the specific area is calculated by “road area detection processing for obtaining the distance d to the plane and the attitude n of the specific plane”.

  FIG. 6A shows the current road surface state, and the specific area is indicated as A. FIG. Next, FIG. 6B shows the road surface state after ΔT seconds, and it can be seen that the portion A which was the specific region shown in FIG. 6A is approaching the vehicle side. In FIG. 6 (b), as in FIG. 6 (a), the road surface of a predetermined area several tens of meters ahead in the traveling direction of the vehicle is determined as a specific area (specific plane) B, and the plane of the specific area is determined. A constant (distance d, slope (normal vector) n) is calculated.

  FIG. 6C shows the road surface state after 2ΔT seconds, and it can be seen that the portions A and B which were the specific areas shown in FIGS. 6A and 6B are approaching the vehicle side. In FIG. 6C, as in FIG. 6A, the road surface of a predetermined area at several tens of meters ahead in the traveling direction of the vehicle is determined as a specific area (specific plane) C, and the plane of the specific area A constant (distance d, slope (normal vector) n) is calculated.

FIG. 6D shows the road surface state after 3 ΔT seconds, and it can be seen that the portions A, B, and C that were the specific regions shown in FIGS. 6A to 6C are approaching the vehicle side. Also in FIG. 6D, as in FIG. 6A, the road surface of the predetermined area at several tens of meters ahead in the traveling direction of the vehicle is determined as the specific area (specific plane) D, and the plane of the specific area A constant (distance d, slope (normal vector) n) is calculated.
As shown in FIGS. 6A to 6D, it can be seen that the road surface approaches the vehicle side together with a stationary object (for example, a telephone pole or a road sign).

Next, as shown in FIG. 7, how to determine the plane constants in the current road surface states A, B, C, and D will be described.
First, as shown in FIG. 7A, a stationary object b and a specific area A exist 3 seconds before T. At present, as shown in FIG. 7B, at present, after 3 ΔT seconds, the specific area A specified in the past (FIG. 7A) is a predetermined distance based on the moving amount of the stationary object b. Only the vehicle side is identified.

  Similarly, as shown in FIG. 7C, a stationary object b and a specific area B exist 2 seconds before T. At present, as shown in FIG. 7D, at the present after 2ΔT seconds, the specific area B specified in the past (FIG. 7C) is a predetermined distance based on the movement amount of the stationary object b. Only the vehicle side is identified.

Similarly, as shown in FIG. 7E, the stationary object b and the specific area C exist before ΔT seconds. At present, as shown in FIG. 7F, at the present time after ΔT seconds, the specific area C specified in the past (FIG. 7E) is a predetermined distance based on the movement amount of the stationary object b. Only the vehicle side is identified.
And now, as shown in FIG.7 (g), the specific area | region D exists.

  From these, as shown in FIG. 7 (h), the area A in which the plane constant was determined 3ΔT seconds ago, the area B in which the plane constant was determined 2ΔT seconds ago, and the plane constant was determined in ΔT seconds ago. The area C and the current area D are obtained as a combined state. Since the plane constants of the areas A to D are specified 3ΔT seconds ago, 2ΔT seconds ago, ΔT seconds ago, and now, respectively, the road conditions (gradients, etc.) in a wide area in the traveling direction of the vehicle are grasped. It can be done.

Next, processing contents by the ECU will be described with reference to block diagrams with reference to FIGS. FIG. 8 is a block diagram showing processing contents in the vehicle road surface detection device according to the embodiment of the present invention, FIG. 9 is a conceptual diagram showing contents of optical flow processing, and FIG. 10 is processing for position correction. It is a flowchart which shows the content.
As shown in FIG. 8, the ECU 6 stores the road surface image captured by the stereo camera 4 in the image storage unit (right) 20 and the image storage unit (left) 22 for each ΔT. The road surface area determination unit 24 determines a road surface area based on the stored information on the road surface image. In this determination unit 24, determination is performed using projective transformation by road area detection processing for obtaining the distance d from the vehicle to the specific plane and the attitude n of the specific plane. The road surface area determination unit 24 may determine a road surface area with respect to a preset traveling direction as a road surface area, or may detect a white line or a road shoulder and determine the road surface area.

  Next, the image processing area (specific area, specific plane) setting unit 26 described above “road area detection processing for obtaining the distance d from the vehicle to the specific plane and the attitude n of the specific plane (the road plane by projective transformation) The specific area for specifying the road surface condition (distance d, slope n) is set to the front side of several tens of meters.

  Next, in the specific plane corresponding point search 28, for each ΔT, the corresponding points of the road surface area (the road surface determined by the road surface area determination unit 24) on the respective imaging screens of the left and right cameras 6 are searched. The corresponding point is a portion having a specific luminance, such as a white line, a road sign, a manhole, etc. (see FIG. 4). Projective transformation can be performed using these corresponding points.

Next, the specific plane plane constant calculation unit 30 calculates a distance di from the vehicle and an attitude (tilt) ni that are plane constants of the specific area set by the image processing area setting unit 26 for each ΔT. Here, the distance and the inclination are calculated based on the parallax angle of the corresponding point set by the specific point corresponding point search unit 28. More specifically, it is performed by the above-described “road area detection processing for calculating the distance d from the vehicle to the specific plane and the attitude n of the specific plane (calculation of the road plane by projective transformation)”.
Further, the specific plane plane constant calculating unit 30 calculates the relative distance (xi, yi) between the vehicle and the stationary object b. The plane constant of the specific plane calculated by the specific plane plane constant calculation unit 30 and the relative distance between the vehicle and the stationary object b are stored in the specific plane plane constant storage unit 32 for each ΔT.

On the other hand, in order to accurately calculate the amount of movement of the specific plane (for example, see FIGS. 6A to 6D), the stationary object detection unit (optical flow processing unit) 34 and the position correction unit 36 perform processing. .
Specifically, as shown in FIG. 9, the stationary object detection unit (optical flow processing unit) 34 performs a matching process on the image at Δt and the image at Δt + 1 to calculate the movement vector of the stationary object b.

  Then, as shown in FIG. 10, the position correction unit 36 first calculates the amount of movement of the host vehicle based on the position change of the stationary object b (movement vector obtained by optical flow) in S1, and then in S2, Based on the amount of movement of the host vehicle, the area where the previous frame image (for example, FIG. 7A) is represented by the current frame image (for example, FIG. 7B) is calculated. Next, in S3, the positions of the previous frame image and the current frame image are specified by matching processing.

Next, the traveling road surface gradient detection unit 38 stores the information on the plane constant (for example, FIG. 7G) of the current specific plane from the specific plane plane constant calculation unit 30 and the specific plane plane constant storage unit 32. In addition, information (for example, FIG. 7B, FIG. (F)) detects the road condition (distance d, slope n) in a wide area in front of the vehicle as shown in FIG. 7 (h).
Then, the safety system 8, the transmission system (AT) 9, and the engine system (ENG) 10 are controlled using the detected road surface gradient information.

Next, with reference to FIG. 11, a flowchart as processing contents in the vehicle road surface detection apparatus according to the embodiment of the present invention will be described. FIG. 11 is a flowchart showing the processing contents in the vehicle road surface detection device according to the embodiment of the present invention. S indicates each step.
As shown in FIG. 11, in S1, various parameters are initialized. Here, i = 0. Next, in S <b> 2, data captured by the stereo camera 4 is stored in the image storage units 20 and 22. Next, in S3, the road surface area determination unit 24 extracts a target area to be a traveling road surface, and in S4, the image processing area setting unit 28 sets a specific area for image processing. Depending on the vehicle speed, this specific area may be set to a far distance at a high speed and close to a low speed, for example. In addition, the area of the specific area may be small at a distance and wide at a near distance. Thus, since the distance to the specific area is changed according to the speed of the vehicle, a specific area suitable for vehicle control and image processing can be set according to the speed of the vehicle. Further, the specific area suitable for vehicle control and image processing can be set by reducing the area of the specific area at a distance and increasing the area at a distance.

Next, in S5, the stationary object detection unit (optical flow processing unit) 34 extracts the stationary object b and calculates the movement vector by the optical flow.
Next, in S <b> 6, the specific plane plane constant calculation unit 34 detects plane data (position di, j, inclination ni, j) of the specific plane Ai, j and stores it in the specific plane plane constant storage unit 2. The

  Next, in S7, whether or not the distance di of the specific plane is smaller than a predetermined small value (for example, several m), and the distance ni of the specific plane cannot be a predetermined large value (for example, normal road) It is determined whether it is greater than (tilt). When the distance di of the specific plane is smaller than the predetermined small value and / or when the distance ni of the specific plane is larger than the predetermined large value, the process is stopped and the process returns to S1. With such a process, for example, when a preceding vehicle has entered the front of the host vehicle, unnecessary processes can be stopped to reduce the processing load.

Next, in S8, the specific plane plane constant at each time Ti-1, Ti-2, T0 stored in the specific plane plane constant storage unit 32 is read. Next, in S9, the plane constant read in S8 is used to calculate the movement amount of the stationary object b processed by the stationary object detection unit (optical flow processing unit) 34 and the position correction unit 36 (relative distance (( x i, y i))))
Next, in S10, a road surface gradient (for example, FIG. 7 (h)) is calculated from the data obtained in the processes of S8 and S9.

  Next, in S 10, the plane constant (position di, ni) and the relative distance (xi, yi) with respect to the stationary object b at the time Ti of the plane A of the specific area are stored in the specific plane plane constant storage unit 32. Next, in S11, i = i + 1 and the process proceeds to the next process.

  As described above, according to the embodiment of the present invention, in order to detect the road surface inclination in a predetermined wide road surface area from the road surface image obtained by imaging the traveling road surface, the imaging is performed from the road surface image captured by the stereo camera 4 that images the traveling road surface. A specific area that is a predetermined distance away from the vehicle on the road surface is set as a specific area, and in this specific area, corresponding points searched for in each road surface image captured by the stereo camera 4 are detected and projected. A plane constant defining a specific plane is calculated by conversion. Then, the specific area and at least one specific area set in the past before the specific area after a predetermined time are combined according to the amount of movement of the vehicle at the predetermined time and set as a traveling road surface. Yes.

  Accordingly, a specific area that is a predetermined distance away from the vehicle on the imaged road surface is set as the specific area, a plane constant is calculated in the specific area, and the specific area and the past before the specific area after a predetermined time are set. Since at least one specific area is combined and set as a traveling road surface according to the amount of movement of the vehicle in a predetermined time, the vehicle from the specific area can be obtained only by image processing of the specific area such as several tens of meters away. It is possible to detect the gradient of the road surface until just before, and to reduce the processing load. In addition, since the specific area and at least one specific area set in the past before this specific area after a predetermined time are combined according to the amount of movement of the vehicle in the predetermined time and set as the road surface, the road surface gradient Detection is also accurate.

In the present embodiment, since the amount of movement of the vehicle is determined based on the positional relationship of a predetermined stationary object in the captured image, the amount of movement of the vehicle is determined using a highly accurate position using the stationary object. Since it can be determined by correction, the road surface gradient can be detected with higher accuracy.
Furthermore, since the moving amount of the vehicle is determined by performing an optical flow process on a predetermined stationary object in the captured image, the moving amount of the vehicle can be determined by the optical flow process, so that the accuracy can be improved. The road surface gradient can be detected.

1 is a conceptual diagram of a vehicle to which a vehicle road surface detection device according to an embodiment of the present invention is applied. It is a flowchart which shows the processing flow of the road area detection process used for the traveling road surface detection apparatus for vehicles by embodiment of this invention. It is a conceptual diagram which shows the example of the process image of the road area detection process used for the traveling road surface detection apparatus for vehicles by embodiment of this invention. It is a figure which shows the example of each corresponding point of the right and left camera used for projective transformation. It is a conceptual diagram which shows the specific area | region which performs the image process set ahead of the advancing direction of a vehicle. Concept for explaining a road surface in which a plane constant is determined by a specific area (a) as shown in FIG. 5 and a specific area (b, c, d) set in the past that has moved toward the vehicle after a predetermined time. FIG. The position (a, c, e) of the specific area where the plane constant is determined in each predetermined time, the position (b, d, f) where the position of the specific area in the past is corrected to the current position, It is a conceptual diagram which shows the position (g) of the specific area | region now. It is a block diagram which shows the processing content in the traveling road surface detection apparatus for vehicles by embodiment of this invention. It is a conceptual diagram which shows the content of the optical flow process. It is a flowchart which shows the processing content of a position correction. It is a flowchart which is the processing content in the traveling road surface detection apparatus for vehicles by embodiment of this invention.

Explanation of symbols

1 vehicle 4 stereo camera 6 ECU

Claims (6)

A vehicle road surface detection device for detecting a road surface inclination in a predetermined wide road surface region from a road surface image obtained by imaging a road surface,
First imaging means for imaging a traveling road surface;
Second imaging means for imaging the traveling road surface so as to obtain a road surface image at least partly overlapping with the road surface image captured by the first imaging means;
Specific area setting means for setting a specific area a predetermined distance away from the vehicle on the imaged road surface as the specific area;
In this specific area, the corresponding point searched for in each road image imaged by the first imaging means and the second imaging means is detected, and a plane constant defining the specific plane is calculated by projective transformation. Specific plane constant calculating means for
Driving road surface setting in which the specific area and at least one specific area set in the past before the specific area after a predetermined time are combined and set as a road surface according to the amount of movement of the vehicle at the predetermined time Means,
A vehicle road surface detection device characterized by comprising:   The vehicle travel road surface detection device according to claim 1, wherein the movement amount of the vehicle is determined based on a positional relationship of a predetermined stationary object in the captured image.   The vehicle travel road surface detection device according to claim 2, wherein the movement amount of the vehicle is determined by performing an optical flow process on a predetermined stationary object in the captured image.   The vehicle travel road surface detection device according to claim 1, wherein the specific area setting unit changes the predetermined distance according to a vehicle speed.   The vehicle road surface detection device according to claim 1, wherein the plane constant is defined by a distance d from a vehicle and an inclination n.   The vehicle according to claim 5, wherein the traveling road surface setting means stops the combination of the specific area corresponding to the movement amount of the vehicle and the past specific area when the slope is equal to or less than the predetermined value and / or the slope n. Road surface detection device.

Images