JP6769263B2 - Road surface judgment method and road surface judgment device - Google Patents

Description

The present invention relates to a road surface determination method and a road surface determination device for determining the road surface of a road.

A device for determining the road surface from the difference between the radiation temperature from the road surface and the radiation temperature from the sky is known (Patent Document 1).

Japanese Unexamined Patent Publication No. 2004-177188

The conventional technique has a problem that the road surface cannot be determined when there is snow on the road.

An object to be solved by the present invention is to determine the road surface even on a road with snow.

In the present invention, based on a radio wave image, a pair of concave regions formed on a road surface on which the vehicle travels and including a boundary of a region where the height of the road surface changes are detected as a pair of first road surface regions , and a pair. determine the intensity ratio of the vertical polarization signal and a horizontal polarization signal of the second road region between the first road area of, based on the intensity ratio of the second road area, to determine the area of a road surface on which the vehicle is traveling By doing so, the above problem is solved.

According to the present invention, the road surface can be determined even if there is snow.

FIG. 1 is a configuration diagram of a road surface determination device according to the present embodiment. FIG. 2A is a diagram showing an example of an image of a road surface to be judged and an example of radio wave image data. FIG. 2B is a diagram showing an example of a determination criterion of an object using an intensity ratio. FIG. 3A is a diagram for explaining a method for setting a determination threshold value. FIG. 3B is a diagram for explaining a region to be determined. FIG. 4A is a second diagram for explaining a method for setting a determination threshold value. FIG. 4B is a second diagram for explaining a region to be determined. It is a flowchart which shows the procedure of the road surface judgment processing which concerns on this embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In this embodiment, a case where the road surface determination device is mounted or arranged on the vehicle will be described as an example.

FIG. 1 shows the configuration of the road surface determination device 100 according to the present embodiment. As shown in FIG. 1, the road surface determination device 100 according to the present embodiment includes an antenna device 1, a signal processing device 2, and a control device 10. These can exchange information with each other. The determination result of the road surface determination device 100 can be used in the in-vehicle device 200. The in-vehicle device 200 includes a vehicle controller 20, a traveling support device 30, and an output device 40. The road surface determination device 100 is connected to the vehicle-mounted device 200 by a CAN (Controller Area Network) or other vehicle-mounted LAN for exchanging information.

The antenna device 1 receives electromagnetic waves such as microwaves and millimeter waves radiated from an object existing around the vehicle. The electromagnetic wave is not particularly limited, and is an electromagnetic wave of about 30 GHz to 10 THz. The antenna device 1 may be a passive device that receives an electromagnetic wave corresponding to the heat radiated from the object, or irradiates the object with an electromagnetic wave such as a millimeter wave and is reflected from the object. It may be an active type device that receives a reflected wave (radiated electromagnetic wave) and recognizes an image of an object. The antenna device 1 of the present embodiment includes an array antenna in which a plurality of antennas (elements) 1a to 1x such as a horn antenna are arranged two-dimensionally, a scanning mechanism, and a lens.

The antenna device 1 receives an electromagnetic wave radiated from an object at a radiation angle (the angle formed by the radiation direction from the object to the antenna device 1 and the vertical direction). The antenna device 1 includes a horizontally polarized component radiated mainly in a substantially horizontal direction with respect to the road surface on which the vehicle travels, and a vertically polarized component radiated mainly in a substantially perpendicular direction with respect to the road surface on which the vehicle travels. To receive. The antennas 1a to 1x that receive the electromagnetic waves of the vertically polarized component and the antennas 1a to 1x that receive the electromagnetic waves of the horizontally polarized component are arranged in a checkered pattern so as to be adjacent to each other.

The objects existing around the vehicle are not particularly limited, and (1) the road surface on which the vehicle travels, (2) granular materials such as snow, mud, sand, gravel, and wood chips laminated on the road surface. Asphalt, (3) signs, traffic lights, road structures such as guardrails, (4) three-dimensional objects such as buildings, (5) moving objects such as pedestrians and other vehicles, (6) sky (Japanese Patent Laid-Open No. 2004-177188) See).

The antenna device 1 converts the electromagnetic waves received by the antennas 1a to 1x into a received signal according to the reception intensity thereof, and outputs the electromagnetic wave to the signal processing device 2. The antennas 1a to 1x that have received the electromagnetic wave of the vertically polarized component output the vertically polarized signal as a received signal to the signal processing device 2. The antennas 1a to 1x that have received the electromagnetic wave of the horizontally polarized component output the horizontally polarized signal as a received signal to the signal processing device 2.

The signal processing device 2 generates radio wave image data based on the vertically polarized signal and the horizontally polarized signal output from the antenna 1a of the antenna device 1. The signal processing device 2 generates a vertically polarized light image by arranging the vertically polarized signals output from the antennas 1a to 1x in two dimensions according to the arrangement positions of the antennas 1a to 1x. The signal processing device 2 generates a horizontally polarized image by arranging the horizontally polarized signals output from the antennas 1a to 1x in two dimensions according to the arrangement positions of the antennas 1a to 1x. The value of each pixel in the vertically polarized image corresponds to the value of the vertically polarized signal. The value of each pixel of the horizontally polarized image corresponds to the value of the horizontally polarized signal. The radio wave image data generation method is not particularly limited, and a radio wave image generation method such as the millimeter wave imaging method known at the time of filing the present application can be appropriately used.

The antenna device 1 and the signal processing device 2 may be configured as one or as separate components. The antenna device 1, the signal processing device 2, and the control device 10 may be configured as one unit or may be arranged in a distributed manner. The antenna device 1, the signal processing device 2, and the control device 10 may all be mounted on the vehicle, or a part thereof may be mounted on the vehicle and the other portion may be provided outside the vehicle. For example, an antenna device 1 and / or a signal processing device 2 is provided as an external device on the road side, and radio image data selected or converted according to the current position of the own vehicle is selected based on the radio image data generated by the external device. , ITS (Intelligent Transport Systems) and other road traffic management systems.

The control device 10 according to this embodiment will be described.
The control device 10 functions as an accessible storage device, a ROM (Read Only Memory) that stores a program that executes a process for determining a road surface, a CPU (Central Processing Unit) that executes a program stored in the ROM, and an accessible storage device. It is equipped with a RAM (Random Access Memory). The control device 10 may be mounted on a vehicle or may be configured as a portable device that can be arranged on the vehicle.

The control device 10 executes a detection process for detecting the boundary of the region where the height of the road surface on which the vehicle travels changes, and a determination process for determining the road surface based on the detection result of the boundary. Hereinafter, each process will be described.

FIG. 2A is a diagram in which an image CM of an image in front of the vehicle and a radio wave image data RM for a part thereof are superimposed and displayed. As shown in the figure, there is snow on the road surface on which the vehicle travels. In the snow cover on the road surface, ruts RTL and RTR are formed along the trajectory of the vehicle (wheel) traveling on the road. A rut is a mark of a wheel left by a car that has passed in the past. In this example, the case where snow is accumulated on the road surface will be described as an example, but the road surface determination device / road surface determination method of the present embodiment can be used when traveling on a road surface that is deformed by the passage of a vehicle. When the road surface is deformed by the passage of a car, when the road surface is covered with mud, especially water-containing mud, the road surface is sand, gravel, chip material (wood chips, shell chips, waste material chips, etc.), granular material. This includes cases where the road surface is deformed due to deterioration of the road surface structure (asphalt layer) or changes in the terrain.

Electromagnetic waves radiated from objects of different materials and temperatures are vertically polarized reception strength, vertically polarized signal value, horizontally polarized reception strength, horizontally polarized signal value, vertically polarized signal and vertically radio wave signal. The intensity ratio of is different. Therefore, the radio wave image data obtained from the vertical radio wave signal and the horizontal radio wave signal of the electromagnetic wave radiated from the object is an image showing the existence and position of the object.

FIG. 2B is a diagram in which the received signal of the electromagnetic wave radiated from the object is plotted experimentally with the horizontal axis as the average reception intensity and the vertical axis as the intensity ratio. The "intensity ratio" in this example is the intensity of the horizontally polarized signal with respect to the intensity of the vertically polarized signal. The coordinates in the upper middle (arrow P) direction of FIG. 2B are relatively stronger in the horizontal polarization signal, and the coordinates in the lower (arrow Q) direction in the figure are relative in strength of the vertically polarized signal. Strong. The intensity ratio may be the intensity of the vertically polarized signal with respect to the intensity of the horizontally polarized signal. As shown in the figure, under preset electromagnetic wave reception conditions, different average reception intensities (values / range) are shown for each object, and different intensity ratios (values or range) are shown for each object. .. That is, the object can be specified based on the coordinate position of the plot in the coordinates where the horizontal axis is the average reception intensity and the vertical axis is the intensity ratio. The average reception strength is the strength obtained by averaging the strength of the horizontally polarized signal and the strength of the vertically polarized signal. Although it is an example, in the example shown in the figure, Ob1 corresponds to an electromagnetic wave radiated from the sky, Ob2 corresponds to an electromagnetic wave radiated from an object having a temperature of about 25 degrees, and Ob3 is radiated from a building. Ob4 corresponds to the snow wall (the part where the height changes) on the road surface, and Ob5 corresponds to the electromagnetic wave radiated from the road surface. Ob6 corresponds to the electromagnetic wave radiated from the asphalt on the road surface, and Ob7 corresponds to the electromagnetic wave radiated from the human. By referring to the plot model shown in the figure, the object can be identified based on the generated radio wave image data (vertically polarized signal, horizontally polarized signal).

In the radio wave image data RM shown in FIG. 2A, the portion of the fresh snow to which no external force is applied after the snowfall has a uniform image (pixel value), but the snow is compacted or pushed away by the passing vehicle. The rut RTL and RTR parts have different images (pixel values). In the radio wave image data RM, the part without light ink is the fresh snow part, and the part with light ink is the part corresponding to the rut. In the present embodiment, the road surface is the surface of the road, and when snow, mud, gravel, etc. are laminated on the asphalt, the uppermost direction (vertical direction) of the snow, mud, gravel, etc. It is an exposed surface in the opposite direction (on the sky side). When a rut is formed by a passing vehicle, there is a difference between the height of the surface of the rut (the surface of the part where the snow is compacted or pushed away) and the height of the surface of the snow-covered part in contact with the rut, resulting in unevenness of the road surface. Appears. A wall extending in the upward direction (opposite to the vertical direction) is formed in the portion from the surface of the rut (bottom surface of the concave portion) to the surface of the snow-covered portion (upper surface of the convex portion).

Even if it is made of the same snow material, the radio wave characteristics of the radiated electromagnetic waves are different between the fresh snow part and the rut part. Furthermore, even in the fresh snow part, the state is different between the inside and the outside of the rut, and the radio wave characteristics of the electromagnetic waves radiated from the snow in each region are different. In the radio wave image data RM, the evaluation points AL and AR in the area of the rut RTL and RTR, the evaluation point B in the area sandwiched between the pair of rut RTL and RTR, and the outside of the rut RTL and RTR (left and right edges of the radio image). The radio wave characteristics of the evaluation points CL and CR in the area on the side) are different from each other. Further, the radio wave characteristics emitted from the evaluation point DL in the area outside the boundary line W of the road surface and where fresh snow is highly accumulated are also different. In addition, the radio wave characteristics radiated from the preceding other vehicle V2 included in the radio wave image data RM are different.

The intensity ratio of each evaluation point (intensity of the horizontally polarized signal to the intensity of the vertically polarized signal) is evaluated with reference to the judgment criteria of the object of FIG. 2B.
Evaluation points A (AR, AL) are located in the area of the compacted ruts. The intensity ratio of the evaluation points A (AR, AL) is observed so that the vertically polarized signal is relatively strong or the horizontally polarized signal is relatively weak. The intensity ratio (horizontal polarization signal intensity / vertically polarization signal intensity) of the evaluation points A (AR, AL) is observed to be 0.80 to 0.85. It approximates the intensity ratio of the object OB6 (asphalt).
Evaluation point B is located in a region of fresh snow having an uneven surface. As for the intensity ratio of the evaluation point B, the horizontally polarized signal is relatively strong or the vertically polarized signal is relatively weaker than the evaluation point A (AR, AL). The intensity ratio (horizontal polarization signal intensity / vertical polarization signal intensity) of the evaluation point B is observed to be 0.95-1.00. It approximates the strength ratio of the object OB4 (snow wall with height difference).
Evaluation points C (CR, CL) are also located in the area of fresh snow. Snow that has been pushed away from the ruts is also mixed in this area. As for the intensity ratio of the evaluation point C (CR, CL), the horizontally polarized signal is relatively strong or the vertically polarized signal is relatively weaker than the evaluation point A. The intensity ratio (horizontal polarization signal intensity / vertical polarization signal intensity) of the evaluation point C is observed to be 1.00 to 1.05. It approximates the strength ratio of the object OB4 (snow wall with height difference). The intensity ratio of the evaluation point C (CR, CL) is close to the intensity ratio of the evaluation point B. This is because none of them is deformed by the vehicle traveling on the road surface. In this example, it is expressed as fresh snow, but it was confirmed that the same tendency can be seen in sand, mud, chips, etc.

Comparing the intensity ratios of each evaluation point based on the intensity ratio (horizontal polarization signal intensity / vertically polarization signal intensity), the intensity ratio of evaluation points A (AR, AL) <intensity ratio of evaluation points B, evaluation points A. The intensity ratio of (AR, AL) <the intensity ratio of the evaluation point C (CR, CL). When the intensity ratio is the inverse number and the intensity ratio of each evaluation point is compared based on the intensity ratio (vertical polarization signal intensity / horizontally polarization signal intensity), [intensity ratio of evaluation points A (AR, AL)> evaluation point B. Intensity ratio of], [Intensity ratio of evaluation point A (AR, AL)> Intensity ratio of evaluation point C (CR, CL)]. The intensity ratio of evaluation point B and the intensity ratio of evaluation point C (CR, CL) are similar, and the intensity ratio of evaluation point B = the intensity ratio of evaluation point C (CR, CL) and the intensity ratio of evaluation point B. <Intensity ratio of evaluation point C (CR, CL), intensity ratio of evaluation point B> An intensity ratio of evaluation point C (CR, CL) can be established.

The control device 10 detects a pair of first road surface regions formed on the road surface on which the vehicle travels, based on the radio wave image. The first road surface region is a concave rut formed on the road surface. The height of the road surface changes on both sides of the bottom of the concave rut. In the region including the boundary of the region where the height of the road surface changes (the region where the wall is formed), the intensity ratio of the vertically polarized signal and the horizontally polarized signal in the radio wave image data changes. The amount of change in the intensity ratio is larger than the amount of change in the intensity ratio in the radio wave image data in the region where the height of the road surface does not change. The control device 10 compares the intensity ratios of the vertically polarized signals and the horizontally polarized signals associated with adjacent pixels / pixel groups in the radio wave image data, and the fluctuation amount (difference) of the intensity ratio is the fluctuation threshold value. In the above case, the coordinate point corresponding to the pixel / pixel group is extracted as a fluctuation point. Here, the intensity ratio may be calculated for each single pixel or for each of a plurality of pixel groups included in a predetermined range. A prediction curve (minimum approximation formula, etc.) connecting the plots of the intensity ratio may be obtained, and if the differential value of the interpolation linear connecting the plots is equal to or greater than the fluctuation threshold value, the plot may be extracted as a fluctuation point.

The fluctuation threshold used for the extraction process of the fluctuation point of the intensity ratio can be set in advance. The fluctuation threshold value may be defined based on the intensity ratio of the region where the height of the road surface changes (the region where the roadside region transitions to the road surface region). The fluctuation threshold value may be set based on the amount of noise obtained from the actually measured radio wave image data. Although not particularly limited, the fluctuation threshold value is set to 2 to 4 times, particularly about 2 times, the error / noise of the intensity ratio obtained when the change in the road surface with no change in height is measured. A fluctuation threshold value may be defined by adding or subtracting a predetermined value to the intensity ratio of the portion transitioning from the roadside region to the road surface region of the actually measured radio wave image data. The fluctuation threshold can be set for each material constituting the road surface, for example, asphalt, snow, mud, sand, gravel, chips, and the like. This is because the signal intensity ratio differs depending on each material. Further, considering that the amount of change in the height of the road surface varies depending on the amount of snowfall, climate, traffic volume, etc., the fluctuation threshold value may be set for each region, each road, and each link.

The control device 10 determines the continuity of the fluctuation points of the extracted intensity ratio. When the extracted fluctuation points have a predetermined relationship / tendency, the control device 10 determines that the fluctuation points have continuity. The control device 10 determines that "the fluctuation points have continuity" when a continuous linearity can be derived by connecting the fluctuation points indicated by the coordinates by using an approximate expression such as the least squares method. For example, the control device 10 compares the fluctuation points adjacent to each other on the coordinates, and the difference in the intensity ratios of the fluctuation points tends to be constant, the intensity ratio of the fluctuation points tends to decrease or increase (fluctuation), and the reception intensity is reduced. If it is found that the intensity ratio of the fluctuation points decreases / increases (fluctuations) as it increases, it is judged that the fluctuation points have continuity.

The road surface determination device 100 of the present embodiment detects the boundary of the region where the height of the road surface changes as the boundary of ruts. Then, the region including the boundary of the region where the height of the road surface changes is detected as the first road surface region. The first road surface region corresponds to the region where the ruts are formed.

In the present embodiment, the boundary of the road surface region is detected by utilizing the fact that the signal of the electromagnetic wave radiated from the road surface region corresponding to the rut and the signal of the electromagnetic wave radiated from the snow-covered portion (wall portion) are different. The road surface determination device 100 calculates the intensity ratio of the vertically polarized signal and the horizontally polarized signal of each pixel from the radio wave image data RM, and the intensity ratio of the vertically polarized signal and the horizontally polarized signal is set as a fluctuation threshold (set). The fluctuation points that are equal to or higher than the threshold value) are extracted, and the feature portion in which the fluctuation points are continuous is extracted. When the relational expression is derived between the extracted fluctuation points, those fluctuation points have continuity. The road surface determination device 100 detects the boundary of the region where the height of the road surface changes based on the continuity of the fluctuation points of the intensity ratio between the vertically polarized signal and the horizontally polarized signal in the radio wave image data RM.

When detecting the first road surface region in the road surface determination device 100 of the present embodiment, the road surface is based on the continuity of the fluctuation points of the intensity ratio between the vertically polarized signal and the horizontally polarized signal in the radio wave image data. The boundary of the region where the height changes is detected, and the region including this boundary is determined to be the first road surface region.
The characteristic "ruts" of the first road surface region are deformable, formed by natural objects, and change depending on the environment. The shape of the rut depends on the location and situation. The shape of the rut changes depending on the snow conditions and traffic volume, and also changes over time as the vehicle passes by. It also depends on the material (mud, sand, gravel) that forms the rut. Therefore, the transition of the signal value on the evaluation line set on the image is easily interrupted, and it is difficult to track a continuous feature (signal feature). In the present embodiment, the boundary of the rut region is not detected simply based on the difference in the intensity of the signal values, but is based on the continuity of the fluctuation points of the intensity ratio between the vertically polarized signal and the horizontally polarized signal. Detect boundaries. In this way, by focusing on the intensity ratio of the vertically polarized signal and the horizontally polarized signal and detecting the first road surface region where the height of the road surface changes based on the continuity of the fluctuation points, the radio wave image data can be obtained. The effect of large fluctuations in the signal value can be eliminated. In this embodiment, attention is paid to the radio wave image data corresponding to the ruts formed on the road surface, and by analyzing the characteristic of the intensity ratio that contributes to the characteristics on the radio wave image data, the influence of the disturbance is eliminated and the intensity is increased. From the continuity of the fluctuation points of the ratio, it is possible to detect the first road surface region in which the height of the road surface including the ruts changes. As a result, the first road surface region can be detected over a long distance.

The road surface determination device 100 detects a position where the change in the intensity of the horizontally polarized signal or the vertically polarized signal is equal to or greater than a predetermined value as the position of the boundary of the region where the height of the road surface changes. The region including this boundary is the first road surface region. In places where the strength of the horizontally polarized signal or the vertically polarized signal changes significantly, the material and temperature are likely to be different, so the position where the signal strength changes is the position of the boundary of the region where the height of the road surface changes. I guess. Further, since the boundary of the region where the height of the road surface changes is formed along the extending direction of the road, the signal strength decreases (changes) as the distance from the antenna device 1 increases. The position where the strength of the road changes is estimated to be the position of the boundary of the region where the height of the road surface changes. Since the boundary of the region where the height of the road surface changes can be detected not only from the viewpoint of the continuity of the fluctuation points of the intensity ratio but also from the viewpoint of the change in intensity, the detection accuracy can be improved. The position of the rut can be accurately detected according to the position of the boundary. The predetermined value is not particularly limited, and can be appropriately set based on the amount of noise of the change in intensity.

The road surface determination device 100 of the present embodiment estimates the existing region of the boundary from the intensity ratio in the radio wave image data, and detects the boundary based on the continuity of the fluctuation points of the intensity ratio in the existing region. As described above, since the intensity ratio differs depending on the object, the object can be narrowed down by the intensity ratio. As shown in FIG. 2B, since the electromagnetic wave signal radiated from the road surface and the road side can be obtained based on the radio wave image data of the road surface imaged in advance on a trial basis, the boundary of the region where the height of the road surface changes. It is possible to narrow down the position or area where is present. By narrowing down the target object and then detecting the boundary based on the continuity of the fluctuation points of the intensity ratio in the radio image data in the existing area, the detection accuracy of the boundary position is improved while reducing the processing load. Can be done. That is, the first road surface region corresponding to the rut can be accurately detected.

The road surface determination device 100 of the present embodiment estimates the existing region of the boundary from the strength of the horizontally polarized signal or the vertically polarized signal, and is based on the continuity of the fluctuation points of the intensity ratio in the radio image data in the existing region. , Detects the boundary of the area where the height of the road surface changes. As described above, since the intensity of the horizontally polarized signal or the vertically polarized signal differs depending on the object, the object can be narrowed down by the intensity. By narrowing down the target object and then detecting the boundary based on the continuity of the fluctuation points of the intensity ratio in the radio image data in the existing area, the detection accuracy of the boundary position is improved while reducing the processing load. Can be done. That is, the first road surface region corresponding to the rut can be accurately detected.

The road surface determination device 100 of the present embodiment determines the continuity of the fluctuation points of the intensity ratio corresponding to the pixels along the traveling direction of the vehicle in the radio wave image data, and detects the boundary based on the determination result. Since the boundary of the area where the height of the road surface changes such as ruts extends along the traveling direction of the vehicle or toward the vanishing point of the radio wave image data, narrow down the pixel area for performing the judgment process. Can be done. As a result, it is possible to improve the detection accuracy of the first road surface region boundary while reducing the processing load.

The road surface determination device 100 of the present embodiment determines the continuity of the fluctuation points of the intensity ratio corresponding to the pixels along the direction toward the vanishing point in the radio wave image data, and detects the boundary based on the determination result. Since the boundary of the area where the height of the road surface changes, such as a rut, extends along the traveling direction of the vehicle, the pixel area for performing the determination process can be narrowed down. As a result, the detection accuracy of the first road surface region can be improved while reducing the processing load.

The road surface determination device 100 of the present embodiment is a rut (first road surface region) in which a boundary having a relatively high or low intensity ratio is formed on the road surface when a plurality of boundary / first road surface regions are detected. Judge. Boundaries with a large difference in intensity in radio wave image data can be extracted as ruts. The method of narrowing down the boundary is not particularly limited, but the boundary has the boundary having the highest or lowest average intensity ratio of the radio wave image data at a predetermined length as the boundary that divides the rut region, and the distance from this boundary is predetermined. Other boundaries within the value (predetermined value is a value according to the wheel width) may be extracted and judged as a pair of ruts. The boundary may be determined as a pair of ruts, the boundary having the highest or lowest average intensity ratio of the radio wave image data at a predetermined length and the boundary having the second highest or lowest average intensity ratio. When a plurality of boundaries are detected, ruts can be appropriately determined by selecting a boundary having a large or small intensity ratio.

When a plurality of boundaries are detected, the road surface determination device 100 of the present embodiment determines that the road surface is a rut that extends along the existence direction of another vehicle V2 traveling in front of the vehicle. To do. The existence of the other vehicle V2 is determined from the radio wave image data. The presence of the other vehicle V2 can be detected from the plot based on the received signal in the other vehicle region. The preceding other vehicle V2 is likely to travel along the rut. Further, it is most appropriate for the own vehicle to travel on the rut on which the other vehicle V2 immediately before travels. Therefore, it is determined that the boundary extending along the existence direction of the other vehicle V2 with respect to the own vehicle is a rut formed on the road surface. When a plurality of boundaries are detected, the ruts (first road surface region) can be appropriately determined by selecting the boundaries along the track.

The above-mentioned road surface determination method has been described by taking a straight road as an example, but the same can be applied to a road having a curvature (curve). For the vertically polarized image, a reference curve based on the curvature of the road surface (road) is set, the plot for each evaluation line is coordinate-converted, and the height of the road surface changes based on the radio wave image data after the coordinate conversion. Boundaries may be detected. The method for converting the coordinates of the radio wave image data is not particularly limited, and a general method known at the time of filing can be used. The reference curve may be calculated based on the curvature associated with the traveling link by obtaining the current traveling link from the map information and the current position using a general navigation device (vehicle-mounted device 200). The reference curvature may be calculated based on the steering angle of the steering wheel acquired from the vehicle controller 20 of the own vehicle. The reference curvature may be calculated based on the curvature of the road detected based on the image captured by the vehicle-mounted camera. The reference curvature may be calculated based on the actually detected boundaries.

The control device 10 identifies the second road surface region between the pair of detected first road surface regions, and obtains the intensity ratio of the vertically polarized signal and the horizontally polarized signal of the second road surface region. By the method described above, the pair of boundary lines is recognized as a pair of first road surface regions (ruts). Then, the intensity ratio in the region between the pair of first road surface regions is obtained from the radio wave image data. The intensity ratio may be the ratio of the intensity of the horizontally polarized signal to the intensity of the vertically polarized signal, or may be the ratio of the intensity of the vertically polarized signal to the intensity of the horizontally polarized signal.

The control device 10 determines the road surface based on the strength ratio of the second road surface region.
According to the road surface determination device 100 of the present embodiment, the area of the road surface can be determined based on the state of the road surface actually traveling. Road conditions change from time to time depending on conditions such as snow, mud, sand and gravel. In this way, the traveling road surface can be determined with high accuracy according to the road surface condition that changes depending on the time and place.

The control device 10 recognizes the third road surface region corresponding to the road side existing outside the first road surface region by using the strength ratio of the second road surface region, and the travelable road surface region including the third road surface region. To judge. The control device 10 sets a determination threshold value based on the second intensity ratio of the second road surface region, and uses this determination threshold value to determine a third road surface region existing outside the pair of first road surface regions.

A method for setting the determination threshold value will be described with reference to FIGS. 3A and 3B.
FIG. 3A is a diagram in which the obtained radio wave image data is plotted in a coordinate system in which the horizontal axis is the average reception intensity and the vertical axis is the intensity ratio. The intensity ratio in this figure is the ratio of the intensity of the horizontal signal to the intensity of the vertically polarized signal. In FIG. 3A, the higher the position of the plot is, the higher the strength of the horizontally polarized signal is, and the lower the position of the plot is, the higher the strength of the vertically polarized signal is. .. The intensity ratio may be the intensity of the horizontally polarized signal with respect to the intensity of the horizontally polarized signal. The reception strength in this figure is the reception strength of the vertically polarized signal.
FIG. 3B is a diagram showing each road surface region in the radio wave image data, that is, the first road surface region A, AR, AL, the second road surface region B, and the third road surface region C, CR, CL.

In the first process of determining the road surface, the road surface determination device 100 detects a first road surface region (rut region) including a boundary where the height of the road surface changes. In this process, the road surface determination device 100 uses an initial threshold value. The initial threshold value is set based on the intensity ratio of the vertically polarized signal and the horizontally polarized signal in the first road surface region. The road surface determination device 100 sets an initial threshold value by adding or subtracting a predetermined quantity to the measured intensity ratio. The initial threshold value can be set by a range with an upper limit value and a lower limit value. A predetermined quantity may be added to the measured intensity ratio to set an upper limit value, and a predetermined quantity may be subtracted from the intensity ratio to set a lower limit value. The intensity ratio may be the intensity ratio of the horizontally polarized signal to the vertically polarized signal, or may be the intensity ratio of the vertically polarized signal to the horizontally polarized signal. When the measured intensity ratio is lower than the initial threshold value, the road surface determination device 100 determines that the signal is a signal based on the electromagnetic wave radiated from the first road surface region. Based on this determination, the road surface determination device 100 identifies the first road surface region. Since the first road surface region where the height of the road surface changes is likely to be formed by the left and right wheels of the vehicle, when the boundary where the height of the road surface changes is searched by the above method, the direction of the road surface is extended. A pair of parallel boundaries are detected along. That is, a pair of first road surface regions are detected from the pair of boundaries.

The road surface determination device 100 detects a second road surface region, which is a region between a pair of first road surface regions. The road surface determination device 100 sets a determination threshold value based on the second intensity ratio of the second road surface region. The road surface determination device 100 detects the third road surface region based on the determination threshold value.

The determination threshold value may be set based on the measured first second intensity ratio, or may be set based on the distribution of a plurality of second intensity ratios. The judgment threshold value can be defined by a single value or by a range with an upper limit value and a lower limit value.

As shown in FIG. 3A, the judgment threshold value (upper limit value when defined by the range) set for detecting the third road surface area is the initial threshold value (value range) set for detecting the first road surface area. It is higher than the upper limit when defined in. By the way, in this example, since the "intensity ratio" is defined as the intensity of the horizontally polarized signal with respect to the intensity of the vertically polarized signal, it is expressed that the judgment threshold is higher than the initial threshold, but the "intensity ratio" is horizontal. When defined as the strength of a vertically polarized signal relative to the strength of the polarized signal, the judgment threshold is lower than the initial threshold. The intensity of the horizontally polarized signal at the intensity ratio of the judgment threshold value may be higher than the intensity of the horizontally polarized signal at the intensity ratio of the initial threshold value. The intensity of the vertically polarized signal at the intensity ratio of the judgment threshold may be lower than the intensity of the vertically polarized signal at the intensity ratio of the initial threshold. If the region including the third road surface region can be detected, the determination threshold value and the initial threshold value may partially overlap.

FIG. 3B shows a pair of first road surface regions AR, AL, second road surface region B, and third road surface regions CR, CL in the radio wave image data. The first road surface region AR and the first road surface region AL extend along the traveling direction (vanishing point direction) of the road surface. The first road surface area AR and the first road surface area AL are located in parallel on the left and right sides of the road surface at intervals to form a pair. The boundaries at which the height of the road surface changes are indicated by ALa, ALb, ARa, and ARb. The first road surface region AR, AL includes boundaries ALa, ALb, ARa, ARb. The first road surface areas AR and AL correspond to the areas where the ruts are formed. The road surface boundary lines WL and WR also serve as boundaries of the third road surface regions CR and CL, and correspond to the left and right ends of the road surface.
If the first road surface areas AR and AL are detected, it is known that the vehicle can travel on the first road surface areas AR and AL, but the third road surface areas CR and CL on both sides thereof must be known. , I can't recognize the road surface that I can actually drive. When it is necessary to drive based only on the positions of the first road surface areas AR and AL, the degree of freedom of driving is restricted. In the present embodiment, even the third road surface areas CR and CL outside the first road surface areas AR and AL are detected, and the road surface over the entire width of the road is accurately recognized.

As shown in FIG. 3A, the strength ratio of the second road surface region B sandwiched between the first road surface regions AR and AL and the strength ratio of the third road surface regions CR and CL outside the first road surface regions AR and AL are Focusing on showing a common range / tendency, the position of the second road surface region B is determined from the positions of the first road surface regions AR and AL, and the strength ratio of the second road surface region B is used to determine the position of the third road surface region CR, Detect CL. That is, the boundary lines WL and WR of the road surface shown in FIG. 3B can be detected. As a result, even in a situation where the first road surface area (rut) AR and AL cannot be detected, it is possible to determine the road surface on which the vehicle can travel. It is possible to prevent the detection from becoming undetectable and accurately determine the range of the road surface on which the vehicle can travel.

Ruts can be detected because they have a characteristic on radio image data that is a boundary where the height of the road surface changes, but the road surface formed of uncompacted snow, mud, sand, gravel, and chips on the outside is detected. It is not easy to identify. When the road surface is made of snow or the like, the condition of the road surface differs depending on the location and environment, so that the road surface cannot be judged based on a fixed threshold value (judgment standard).

In the present embodiment, since the judgment threshold value is set using the intensity ratio of the second road surface region between the first road surface regions, the influence of the place and the environment is eliminated, and the judgment threshold value according to the place and the environment is eliminated. The position of the third road surface region outside the first road surface region can be determined. Even if the road surface is covered with snow, mud, sand, gravel, and chips, the area of the road surface that can be driven can be properly determined. It is not limited to the first road surface area having a characteristic of shape such as ruts, and it is possible to judge the road surface of the entire width of the road, so that useful information can be shown to the driver and the degree of freedom of driving control and driving support is improved. Can be done. Even when you have to drive other than ruts, you can recognize the area of the road surface where you can drive. It is different from the one that detects only the first road surface areas AR and AL corresponding to the ruts and the second road surface area B between them.

It is difficult to judge between the first road surface region (rut) and the third road surface region because the shape is complicated. When the central part of the asphalt road is depressed and water is accumulated there, it is difficult to judge the first road surface area only by the received signal and the threshold value. Similarly, even when gravel or the like is laminated on the second road surface region and a gap is formed, it is difficult to determine the first road surface region only by the received signal and the threshold value. In the present embodiment, the third road surface region is determined, and based on the determination result, the travelable road surface is determined based on the outermost end of the road (see the boundary lines WL and WR of the road surface in FIG. 4B). That is, even if the first road surface region (rut) cannot be detected, it is possible to determine the road surface on which the vehicle can travel. As a result, it is possible to prevent the detection from becoming undetectable and to accurately determine the range of the road surface on which the vehicle can travel.

The control device 10 has a first determination threshold value used when determining a road surface less than a predetermined distance from the vehicle and a second determination used when determining a road surface equal to or more than a predetermined distance from the vehicle in the process of setting the determination threshold value. Two judgment thresholds with the threshold are set. At this time, the range (value range) of the first determination threshold value is set smaller than the range (value range) of the second determination threshold value. That is, the difference between the upper limit value and the lower limit value of the first judgment threshold value is smaller than the difference between the upper limit value and the lower limit value of the second judgment threshold value.

The closer the distance from the antenna device 1, the stronger the intensity of the received signal and the higher the accuracy of the intensity ratio. Therefore, the shorter the distance from the antenna device 1, the narrower the width of the first judgment threshold value used for the judgment process, and the farther the distance from the antenna device 1, the wider the width of the second judgment threshold value used for the judgment process is set. .. The third road surface region can be accurately determined according to the characteristics of the received signal. Further, the processing load can be reduced by narrowing the width of the first determination threshold value.

Based on FIGS. 4A and 4B, a method for setting a judgment threshold value using an image of another vehicle traveling in front of the vehicle will be described.
Since FIG. 4A is basically common to FIG. 3A, the description of FIG. 3A is incorporated. FIG. 4A shows a region in which the intensity ratio based on electromagnetic waves radiated from other vehicles is plotted in addition to FIG. 3A.
Since FIG. 4B is basically common to FIG. 3B, the description of FIG. 3A is incorporated. FIG. 4B further shows another vehicle V2 traveling in front of the vehicle. Since the basic processing is common to the contents described with reference to FIGS. 3A and 3B, the differences will be briefly described below, and the above description will be incorporated for details.

The road surface determination device 100 detects a pair of first road surface regions (rut regions) including a boundary where the height of the road surface changes, using an initial threshold value.

The road surface determination device 100 detects a second road surface region, which is a region between a pair of first road surface regions.
The road surface determination device 100 uses an image of another vehicle V2 when detecting a second road surface region. When a plurality of pairs of first road surface regions are detected based on the radio wave image data, the pair of regions connected to the other vehicle V2 is detected as the first road surface region. As shown in FIG. 4B, in the radio wave image data, the region extending in the −Y direction (lower direction in the figure) of the other vehicle V2 is the second road surface region. The road surface determination device 100 detects the second road surface region by utilizing this positional relationship.

The road surface determination device 100 detects another vehicle V2 traveling in front of the vehicle, and detects a region connected to the other vehicle V2 as a second road surface bizarre B. Specifically, the road surface determination device 100 detects the region between the ruts (first road surface region) connected to the pair of wheels of the other vehicle V2 as the second road surface region B. As shown in FIG. 4B, the wheels of the other vehicle V2 are connected to the first road surface region RTL and RTR. The second road surface region B can be detected between the first road surface regions RTL and RTR. As a result, when another vehicle V2 is present, the second road surface region can be detected in a short time (several milliseconds to several seconds). Since the image of the other vehicle V2 can be recognized more accurately than other objects, the second road surface area B is excluded from the influence of the environment (weather changes such as rain, wind, snow, etc., and disturbances such as temperature changes). Can be detected.

The road surface determination device 100 sets a determination threshold value based on the second intensity ratio of the second road surface region. The road surface determination device 100 detects the third road surface region based on the determination threshold value. The method for setting the judgment threshold is as described above.

As described above, the control device 10 determines the third road surface region and detects the outermost end of the travelable road surface region.
The detected position information of the road surface on which the vehicle can travel, that is, the position on the outside of the road in the third road surface region is transmitted to the vehicle controller 20 of the vehicle-mounted device 200. The vehicle controller 20 transmits the position information of the road surface to the traveling support device 30. The travel support device 30 supports the travel of the own vehicle so that the own vehicle is located inside the determined traversable road surface. The travel support device 30 may use the position information of the pair of first road surface areas as the position information of the lane mark of the road. There is snow on the road surface, and depending on the driver's vision and camera image, it may not be possible to know where the road surface can be driven. Similarly, on muddy roads and gravel roads that have been roughened by the running of vehicles, it may not be possible to know from where to where the road surface can be traveled. In particular, the condition of the road surface covered with snow, mud, gravel, sand, chips, etc. varies depending on the location and environment. In such a situation, if the road surface is misjudged, the wheels may be caught in the gutter.
In the present embodiment, since the judgment threshold value based on the actual measurement data is set in consideration of the influence of the place and the environment, the outermost position of the road surface on which the vehicle can travel can be accurately detected even in such a situation. ..
In a scene where it is difficult to determine the area of the road surface, it is preferable that the area can be determined even for a farther road surface. In the present embodiment, the boundary of the region where the height of the road surface changes is detected based on the continuity of the fluctuation points of the intensity ratio of the vertically polarized signal and the horizontally polarized signal in the radio wave image data. Even when the radio wave image data fluctuates drastically depending on the situation such as snow, mud, sand, and gravel, it is possible to determine the boundary and the road surface that can be driven farther.

Hereinafter, the control procedure of the road surface determination device 100 of the present embodiment will be described based on the flowchart of FIG.

In step 101, the antenna device 1 receives an electromagnetic wave radiated from an object existing around the vehicle. The electromagnetic wave includes a horizontally polarized component radiated mainly in a substantially horizontal direction with respect to the road surface on which the vehicle travels, and a vertically polarized component radiated mainly in a substantially perpendicular direction with respect to the road surface on which the vehicle travels. The reason why it is expressed that it is mainly radiated in the horizontal direction is because even if it is controlled to radiate in the horizontal direction, it is possible that not all electromagnetic waves actually go in the horizontal direction. Similarly, the expression that it is radiated in the substantially vertical direction is also considered because even if it is controlled, it is possible that not all electromagnetic waves actually go in the vertical direction.

In step 102, the signal processing device 2 generates radio wave image data using a horizontally polarized signal based on a horizontally polarized component and a vertically polarized signal based on a vertically polarized component. The control device 10 acquires the generated radio wave image data.

In step 103, the control device 10 estimates the existing area of the object. The control device 10 estimates the existence region of the boundary from the intensity ratio in the radio wave image data. The control device 10 estimates the existence region of the boundary from the distribution of the intensity of the horizontally polarized signal or the vertically polarized signal in the radio wave image data. The control device 10 may determine the existing region of the first road surface region by using the initial threshold value. You may skip step 103 and proceed from step 102 to step 104.

In step 104, the control device 10 calculates the intensity ratio. The intensity ratio may be a vertically polarized signal with respect to the horizontally polarized signal, or may be a horizontally polarized signal with respect to the vertically polarized signal. The control device 10 calculates the intensity ratio only within the existing region of the first road surface region of the road surface estimated in step 103. The control device 10 may calculate the intensity ratio for the entire radio wave image data. In this case, step 103 is skipped and step 104 is executed.

In step 105, the control device 10 refers to the initial threshold value and detects as the first road surface region a pixel region in which the measured intensity ratio is included in the value range of the predetermined initial threshold value.
Further, the control device 10 detects the boundary of the region where the height of the road surface changes based on the continuity of the fluctuation points of the intensity ratio of the vertically polarized signal and the horizontally polarized signal in the radio wave image data. The first road surface region includes this boundary. The fluctuation point of the intensity ratio is a point corresponding to a pixel or a pixel group in which the intensity ratio changes by or more than a predetermined fluctuation threshold value. The control device 10 may detect a position where the change in the intensity of the horizontally polarized signal or the vertically polarized signal in the radio wave image data is equal to or more than a predetermined value as the position of the boundary of the region where the height of the road surface changes. The control device 10 may detect the first road surface region including the boundary based on the continuity of the fluctuation points of the intensity ratio corresponding to the pixels along the traveling direction of the vehicle. The first road surface region is a pair of regions arranged in parallel at equal intervals along the extending direction of the road surface. The control device 10 may detect the first road surface region including the boundary based on the continuity of the fluctuation points of the intensity ratio corresponding to the pixels along the vanishing point direction in the radio wave image data.

When a four-wheeled vehicle travels, a pair of left and right regions where the height of the road surface changes is formed. On a wide road, each vehicle may travel in a different position, so that there may be three or more regions where the height of the road surface changes. In that case, the control device 10 determines whether or not three or more boundaries have been detected. When three or more boundaries are detected, the control device 10 determines that the boundary having a relatively high intensity ratio or a relatively low intensity ratio is a rut formed on the road surface. It is determined that the position of the characteristic boundary where the value of the intensity ratio is higher / or lower than the other intensity ratio corresponds to the position of the rut. From another point of view, it is determined that the boundary extending along the direction of existence of the other vehicle traveling in front of the vehicle is a rut formed on the road surface. Finally, the position of the pair of first road surface regions is detected, and the process proceeds to step 106.

In step 106, the control device 10 detects the second road surface region between the pair of first road surface regions in the radio image data.
When the other vehicle V2 is present in front of the own vehicle, the region between the loci of the pair of wheels of the other vehicle V2 may be determined as the second road surface region.

In step 107, the control device 10 acquires the detected second intensity ratio of the second road surface region. The intensity ratio is the ratio of the intensity of the horizontally polarized signal based on the horizontally polarized component to the intensity of the vertically polarized signal based on the vertically polarized component. It may be the strength of the vertically polarized signal with respect to the strength of the horizontally polarized signal, or may be the strength of the horizontally polarized signal with respect to the strength of the vertically polarized signal.

In step 108, the control device 10 calculates the determination threshold value based on the second intensity ratio. The range of the judgment threshold value / judgment threshold value may be obtained based on the distribution of the second intensity ratio, or the value in consideration of the detection error may be added or subtracted from the second intensity ratio. The control device 10 may set the range of the first determination threshold value for determining the road surface near the own vehicle to be smaller than the range of the second determination threshold value for determining the road surface remote from the own vehicle.

In step 109, the control device 10 determines the third road surface region using the determination threshold value. The determination threshold value is a threshold value for distinguishing (distinguishing) the second and third road surface regions from the first road surface region. As shown in FIGS. 3A and 4A, the intensity ratio of the first road surface region (intensity of the horizontally polarized signal / strength of the vertically polarized signal) is lower than the judgment threshold, and the intensity ratio of the second and third road surface regions (intensity of the second and third road surface regions). The strength of the horizontally polarized signal / the strength of the vertically polarized signal) is higher than the judgment threshold. When the intensity ratio is defined as the intensity of the vertically polarized signal to the intensity of the horizontally polarized signal (strength of the vertically polarized signal / strength of the horizontally polarized signal), the intensity ratio of the first road surface region (horizontally polarized signal). (Strength of / vertically polarized signal) is higher than the judgment threshold, and the strength ratio of the second and third road surface regions (strength of the horizontally polarized signal / strength of the vertically polarized signal) is lower than the judgment threshold.

The third road surface region is detected by utilizing the characteristic of this intensity ratio. The third road surface region is located outside the first and second road surface regions. By detecting the third road surface region, the position of the outermost end of the road surface can be detected.

In step 110, when the third road surface region can be detected, the control device 10 determines that the outer extension (outer end) of the third road surface region is a travelable road surface region. On the other hand, in step 111, the control device 10 determines that the region that cannot be detected as the third road surface region is a region that cannot travel (not the road surface).

In step 112, the control device 10 outputs the information of the position of the obtained third road surface area or the road surface area / position corresponding to the entire width of the road derived from the position to the in-vehicle device 200. The in-vehicle device 200 may transmit these results to the driver via an output device 40 such as a display or a microphone, or the traveling support device may use the boundary position information as the lane mark or the road surface position information of the traveling path. It may be input to 30 and used for lane keeping running or automatic driving of a vehicle.

The road surface determination device 100 according to the embodiment of the present invention, which is configured and operates as described above, and the road surface determination method used therein have the following effects.

[1] The road surface determination device 100 of the present embodiment or the determination method used therein determines the road surface based on the strength ratio of the second road surface region of the actually traveling road surface. The area can be determined based on the actual road surface condition. Road conditions change from time to time depending on conditions such as snow, mud, sand and gravel. In this way, the traveling road surface can be determined with high accuracy according to the road surface condition that changes depending on the time and place.

[2] The road surface judgment device 100 of the present embodiment or the judgment method used for the road surface judgment device 100 sets a judgment threshold value using the strength ratio of the second road surface area between the first road surface areas, and thus influences the place and environment. The position of the third road surface region outside the first road surface region can be determined based on the determination threshold value according to the location and the environment. Even if the road surface is covered with snow, mud, sand, gravel, and chips, the area of the road surface that can be driven can be properly determined. It is not limited to the first road surface area having a characteristic of shape such as ruts, and it is possible to judge the road surface of the entire width of the road, so that useful information can be shown to the driver and the degree of freedom of driving control and driving support is improved. Can be done.
In the present embodiment, the third road surface region is determined, and based on the determination result, the travelable road surface is determined based on the outermost end of the road (see the boundary lines WL and WR of the road surface in FIG. 4B). That is, even if the first road surface region (rut) cannot be detected, it is possible to determine the road surface on which the vehicle can travel. As a result, it is possible to prevent the detection from becoming undetectable and to accurately determine the range of the road surface on which the vehicle can travel.

[3] The road surface determination device 100 of the present embodiment or the determination method used therein includes a first determination threshold value used when determining a road surface less than a predetermined distance from the vehicle in the process of setting the determination threshold value, and the vehicle. Two judgment threshold values, that is, a second judgment threshold value used when judging a road surface of a predetermined distance or more from the above, are set. The range (value range) of the first judgment threshold value is set smaller than the range (value range) of the second judgment threshold value. The closer the distance from the antenna device 1, the stronger the intensity of the received signal and the higher the accuracy of the intensity ratio. Therefore, the shorter the distance from the antenna device 1, the narrower the width of the first judgment threshold value used for the judgment process, and the farther the distance from the antenna device 1, the wider the width of the second judgment threshold value used for the judgment process is set. .. The third road surface region can be accurately determined according to the characteristics of the received signal.

[4] The road surface determination device 100 of the present embodiment or the determination method used therein uses an image of another vehicle V2 when detecting a second road surface region. When a plurality of pairs of first road surface regions are detected based on the radio wave image data, the pair of regions connected to the other vehicle V2 is detected as the first road surface region. The second road surface area is detected by using the positional relationship between the other vehicle V2 and the second road surface area in the radio wave image data. As a result, when another vehicle V2 is present, the second road surface region can be easily detected.

[5] The road surface determination device 100 of the present embodiment or the determination method used therefor is based on the continuity of the fluctuation points of the intensity ratio between the vertically polarized signal and the horizontally polarized signal in the radio wave image data. The boundary of the first road surface region including the boundary of the region where the height changes is detected. Areas where the height of the road surface changes, such as ruts, can be deformed, formed by natural objects, and change depending on the environment. The shape of the rut depends on the location and situation. The shape of the rut changes depending on the snow conditions and traffic volume, and also changes over time as the vehicle passes by. It also depends on the material (mud, sand, gravel) that forms the rut. Therefore, the transition of the signal value on the evaluation line set on the image is easily interrupted, and it is difficult to track a continuous feature (signal feature). In the present embodiment, the boundary of the region where the height of the road surface changes is not simply detected based on the difference in the intensity of the signal values, but the fluctuation point of the intensity ratio between the vertically polarized signal and the horizontally polarized signal. The boundary is detected based on the continuity of. In this way, by focusing on the intensity ratio of the vertically polarized signal and the horizontally polarized signal and detecting the boundary of the region where the height of the road surface changes based on the continuity of the fluctuation points, the signal of the radio wave image data. The effect of large fluctuations in the value can be eliminated. In this embodiment, attention is paid to the radio wave image data corresponding to the ruts formed on the road surface, and by analyzing the characteristic of the intensity ratio that contributes to the characteristics on the radio wave image data, the influence of the disturbance is eliminated and the intensity is increased. From the continuity of the fluctuation points of the ratio, the first road surface region including the boundary where the height of the road surface including the ruts changes can be detected. As a result, the road surface can be detected over a long distance.

[6] The road surface determination device 100 of the present embodiment exerts the above-mentioned effects.

It should be noted that the embodiments described above are described for facilitating the understanding of the present invention, and are not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

100 ... Road surface judgment device 1 ... Antenna device 2 ... Signal processing device 10 ... Control device 11 ... CPU
12 ... ROM
13 ... RAM
200 ... In-vehicle device 20 ... Vehicle controller 30 ... Travel support device 40 ... Output device

Claims (6)

Regarding electromagnetic waves radiated from objects existing around the vehicle, a horizontally polarized component radiated mainly in a substantially horizontal direction with respect to the road surface on which the vehicle travels, and mainly with respect to the road surface on which the vehicle travels. Receives vertically polarized components radiated approximately vertically,
Radio wave image data is generated using the horizontally polarized signal based on the horizontally polarized component and the vertically polarized signal based on the vertically polarized component.
Based on the wave image data is formed on the road surface on which the vehicle travels, and detects a pair of recessed region including a boundary of a region where the height of the road surface varies as a pair of first road area,
The intensity ratio of the vertically polarized signal and the horizontally polarized signal in the second road surface region between the pair of first road surface regions was determined.
A road surface determination method for determining an area of a road surface on which the vehicle travels based on the strength ratio of the second road surface area. A judgment threshold value based on the second intensity ratio of the second road surface region is set.
The road surface determination method according to claim 1, wherein a third road surface region existing outside the pair of first road surface regions is determined using the determination threshold value. In the process of setting the judgment threshold,
The range of the first judgment threshold value used when judging the road surface less than a predetermined distance from the vehicle is set smaller than the range of the second judgment threshold value used when judging the road surface equal to or more than a predetermined distance from the vehicle. The road surface determination method according to claim 2. Based on the radio wave image data, another vehicle traveling in front of the vehicle is detected.
The road surface determination method according to any one of claims 1 to 3, wherein a region connected to the other vehicle is detected as the second road surface region. In the process of detecting the first road surface region,
Based on the continuity of the fluctuation points of the intensity ratio between the vertically polarized signal and the horizontally polarized signal in the radio wave image data, the boundary of the region where the height of the road surface changes is detected.
The road surface determination method according to any one of claims 1 to 4, wherein the first road surface region including the boundary is detected. A road surface judgment device including an antenna, a signal processing device, and a control device.
The antenna has a horizontally polarized component radiated mainly in a substantially horizontal direction with respect to a road surface on which the vehicle travels, and a road surface on which the vehicle travels, with respect to electromagnetic waves radiated from an object existing around the vehicle. On the other hand, it receives the vertically polarized component mainly radiated in the substantially vertical direction,
The signal processing device generates radio wave image data generated by using the horizontally polarized signal based on the horizontally polarized component and the vertically polarized signal based on the vertically polarized component.
Wherein the control device, based on the radio wave image data is formed on the road surface on which the vehicle travels, we detected a pair of recessed region including a boundary of a region where the height of the road surface varies as a pair of first road area And
The intensity ratio of the vertically polarized signal and the horizontally polarized signal in the second road surface region between the pair of first road surface regions was determined.
A road surface determination device that determines an area of the road surface on which the vehicle travels based on the strength ratio of the second road surface area.