JP2017036986A - Control method for road surface detection apparatus, and road surface detection apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control method for a road surface detection apparatus, the method enabling an appropriate determination of a road surface.SOLUTION: A control method is used for a road surface detection apparatus that includes an antenna device 110 that has an array antenna 113 in which a first antenna element 111 and a second antenna element 112 are arranged in two dimensions, where the first antenna element is for outputting a first polarization signal by receiving a reception wave in a first polarization direction incoming from an object and the second antenna element is for outputting a second polarization signal by receiving a reception wave in a second polarization direction having a polarization direction different from the first antenna element 111, and that generates an image on the basis of the first and second polarization signals obtained from the antenna device 110 and determines a road surface on the basis of the image. Further, the method includes: detecting a border line candidate of a road surface from the image; calculating a change rate of a ratio between an intensity of the first polarization signal and that of the second polarization signal along a border line candidate in the case of the border line candidate crossing; and determining that the border line candidate is a border line of the road surface in the case of the change rate of the ratio falling in a first determination range.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for controlling a road surface detection device that detects a road surface of a road and a road surface detection device.

  Conventionally, a technique for determining a road surface condition by measuring a road surface radiation temperature based on horizontal and vertical polarization components received from a road surface and calculating a road surface emissivity is known. (For example, Patent Document 1).

JP 2004-177188 A

  However, when determining whether or not the road surface by measuring the radiation temperature of the object based on the received waves of the horizontally polarized wave component and the vertically polarized wave component arriving from the object as in the prior art Even if it is the same road surface, the radiation temperature of the road surface is different between the shaded part and the sunlit part, so it may be erroneously determined that one part is not the road surface and the other part is the road surface. there were.

  The problem to be solved by the present invention is to provide a control method for a road surface detection device that can appropriately determine the road surface.

  The present invention includes a first antenna element that receives a received wave in a first polarization direction coming from an object and outputs a first polarization signal, and a received wave in a second polarization direction and receives a second polarized wave. An image is generated based on an antenna device having an array antenna in which a second antenna element that outputs a wave signal is two-dimensionally arranged, and the first polarization signal and the second polarization signal acquired from the antenna device A control method for a road surface detection device for determining a road surface based on the image, wherein when a boundary candidate for a road surface is detected from the image and the boundary line candidates intersect, a first bias is detected along the boundary line candidate. When the ratio change rate at the position along the boundary line candidate is calculated by calculating the ratio between the intensity of the wave signal and the intensity of the second polarization signal, and the ratio change rate is within the first determination range In addition, the above problem can be solved by determining the boundary line candidate as a road boundary line. To.

  According to the present invention, even when the boundary between the road shade and the sun is detected as a road boundary candidate due to the difference in temperature between the road shade and the sun, the position at the position along the boundary candidate is When the rate of change in the ratio between the intensity of the first polarization signal and the intensity of the second polarization signal is within the first determination range, the boundary line candidate is determined as the boundary line of the road surface, It can be judged appropriately.

It is a block diagram which shows the structure of the road surface detection apparatus which concerns on this embodiment. It is a figure which shows an example of the array antenna with which the antenna apparatus which concerns on this embodiment is provided. It is a figure which shows the scene where the boundary line of a shade and a sun crosses a road surface. (A) is a figure which shows an example of the vertical polarization image in the scene shown in FIG. 3, (B) is a figure which shows an example of the horizontal polarization image in the scene shown in FIG. It is a figure which shows an example of ratio of the intensity | strength of the vertical polarization signal of a 1st determination line and the 2nd determination line shown in FIG. 4, and the intensity | strength of a horizontal polarization signal. FIG. 5 is a diagram illustrating an example of a rate of change in the ratio between the intensity of the horizontally polarized signal and the intensity of the vertically polarized signal on the first determination line illustrated in FIG. 4. It is a figure which shows an example of the change rate of ratio of the intensity | strength of the horizontal polarization signal of the 2nd determination line shown in FIG. 4, and the intensity | strength of a vertical polarization signal. It is a figure which shows the scene where the boundary line of a shade and a sun is parallel to a road surface. (A) is a figure which shows an example of the vertical polarization image in the scene shown in FIG. 8, (B) is a figure which shows an example of the horizontal polarization image in the scene shown in FIG. It is a figure for demonstrating the determination method of a road surface boundary line in the scene shown in FIG. It is a figure which shows an example of the change rate of ratio of the intensity | strength of the horizontal polarization signal in the orthogonal determination line shown in FIG. 10, and the intensity | strength of a vertical polarization signal. It is a flowchart (the 1) which shows the road surface determination process which concerns on this embodiment. It is a flowchart (the 2) which shows the road surface determination process which concerns on this embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the present embodiment, a configuration in which the road surface detection device is mounted on a vehicle will be described as an example.

  FIG. 1 is a diagram illustrating a configuration of a road surface detection device 100 according to the present embodiment. As illustrated in FIG. 1, the road surface detection device 100 according to the present embodiment includes an antenna device 110 and a processing device 120. These devices are connected by a CAN (Controller Area Network) or other in-vehicle LAN in order to exchange information with each other.

  The antenna device 110 receives a millimeter wave coming from an object (including a road surface and a road side) existing in front of the host vehicle. As shown in FIG. 2, the antenna device 110 includes an array antenna 113 in which a plurality of antenna elements such as a horn antenna are arranged in a two-dimensional manner. By receiving millimeter waves at each of these antenna elements, as shown in FIG. 4, it is possible to generate an imaging image including polarization information of a radio wave radiated from an object (details will be described later). . FIG. 2 is a diagram illustrating an example of the array antenna 113 included in the antenna device 110 according to the present embodiment. The antenna device 110 may be configured to receive radio waves and electromagnetic waves in a frequency band of millimeter waves or more.

  As shown in FIG. 2, the array antenna 113 includes a first antenna element 111 that mainly receives a reception wave having a vertical polarization component and a second antenna element 112 that mainly receives a reception wave having a horizontal polarization component. Have. The first antenna elements 111 and the second antenna elements 112 are alternately arranged two-dimensionally.

  In the antenna device 110 mounted on the vehicle, in order to detect a detection target, the viewing angle of the array antenna 113 is preferably at least 20 ° in the vertical direction and 40 ° or more in the horizontal direction. Further, when the detection target is a pedestrian, it is preferable that a pedestrian having a width of 20 cm can be detected by about 10 pixels in the vertical direction about 50 m ahead. Therefore, in order to obtain an image with a viewing angle suitable for the array antenna 113, it is preferable that the resolution is 20 pixels in the vertical direction and 40 pixels in the horizontal direction, as shown in FIG. Further, when the received wave to be received is a millimeter wave in the 150 GHz band, the size of the receiving antenna element needs to be about 4 mm. Therefore, the size of the array antenna 113 can be designed so that the horizontal direction is 40 pixels × 4 mm = 160 mm and the vertical direction is 20 pixels × 4 mm = 80 mm.

  In this way, by setting the size of the receiving surface of the array antenna 113, it becomes possible to appropriately detect a detection target such as a pedestrian. In addition, a detection target object is not limited to a pedestrian, For example, solid objects, such as a vehicle and a telephone pole, the road surface of a road, a roadside, etc. are also included. For example, the antenna device 110 according to the present embodiment receives a received wave reflected on the road surface of the road, and detects the road surface shape such as whether the road surface is uneven or the road is curved as a detection target. Can be detected.

  The antenna device 110 converts the received wave received by the antenna elements 111 and 112 into a received signal having a strength corresponding to the received strength, and outputs the received signal to the processing device 120. In the following description, the reception signal output from the first antenna element 111 that receives the reception wave of the vertical polarization component is a vertical polarization signal, and the reception is output from the second antenna element 112 that receives the reception wave of the horizontal polarization component. The signal will be described as a horizontally polarized signal.

  The processing device 120 includes a ROM (Read Only Memory) that stores a program for detecting a road surface based on the vertical polarization signal and the horizontal polarization signal output from the antenna device 110, and is stored in the ROM. CPU (Central Processing Unit) that executes the program and RAM (Random Access Memory) that functions as an accessible storage device. As an operation circuit, instead of or in addition to a CPU (Central Processing Unit), an MPU (Micro Processing Unit), a DSP (Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), etc. Can be used.

  The processing device 120 executes a program stored in the ROM by the CPU, thereby generating an imaging image based on the vertical polarization signal and the horizontal polarization signal, and a road boundary candidate from the imaging image. Boundary line candidate detection function for detecting the boundary line, determination line setting function for setting a determination line for determining whether or not the boundary line candidate is a road boundary line, and the intensity and horizontal polarization of the vertical polarization signal on the determination line A road surface determination function for determining whether or not the boundary line candidate is a road surface boundary line based on a ratio to the signal strength. Below, each function with which the processing apparatus 120 is provided is demonstrated.

  The image generation function of the processing device 120 generates an imaging image based on the vertical polarization signal and the horizontal polarization signal output from the array antenna 113 of the antenna device 110. Specifically, the image generation function arranges each vertically polarized signal output from each first antenna element 111 in a two-dimensional manner in accordance with the arrangement of the first antenna elements 111, thereby obtaining a vertically polarized signal. Can be generated as a vertically polarized image. In addition, the image generation function performs imaging based on the horizontal polarization signal by arranging each horizontal polarization signal output from each second antenna element 112 in a two-dimensional manner in accordance with the arrangement of the first antenna elements 111. The image can be generated as a horizontally polarized image. Hereinafter, the vertical polarization signal or the horizontal polarization signal constituting the vertical polarization image and the horizontal polarization image will be described as pixels of the vertical polarization image and the horizontal polarization image. As shown in FIG. 2, since the first antenna elements 111 and the second antenna elements 112 are alternately arranged, the imaging ranges of the first antenna elements 111 and the second antenna elements 112 are slightly different. In, for example, the first antenna element 111 located at the upper left in the array antenna 113 shown in FIG. 2 and the second antenna element 112 on the right side (or the second antenna element 112 on the lower side) are Description will be made assuming that the same imaging range is imaged.

  As shown in FIG. 3, in the scene where the boundary line between the shade and the sun crosses the road surface, the image generation function generates a vertically polarized image based on the vertically polarized signal as shown in FIG. Generate. In the scene shown in FIG. 3, the image generation function generates a horizontally polarized image based on the horizontally polarized signal as shown in FIG. In the example shown in FIGS. 4A and 4B, the higher the intensity of the vertical polarization signal and the horizontal polarization signal, the lighter the color is expressed.

  The boundary line candidate detection function of the processing device 120 detects road surface boundary line candidates in the vertical polarization image and the horizontal polarization image. For example, the boundary line candidate detection function has a predetermined number of pixels (for example, two pixels) in the horizontal direction (X direction in FIG. 4) or the vertical direction (Y direction in FIG. 4) in the vertical polarization image and the horizontal polarization image. It is possible to detect a pixel in which the difference between the output values of two distant pixels is equal to or greater than a predetermined value, and to detect a pixel row in which the detected pixels continue for a predetermined pixel or more as a boundary line candidate. The boundary line candidate detection method is not limited to the above example, and a known edge detection method can be used.

  In the example shown in FIG. 3, a boundary line exists between the road surface on which the host vehicle travels and the road side, and a boundary line also exists between the shade and the sun. Since the boundary between the road surface on which the vehicle is traveling and the roadside intersects with the boundary between the shade and the sun, the boundary between the shade and the sun goes across the road and the roadside. It will be. Since the road surface and the road side are different in material and structure and have different reflectivities, the intensity of the vertical polarization signal and the horizontal polarization signal often differs between the road surface and the road side. For example, in the example shown in FIG. 4A, the intensity of the vertically polarized signal on the road surface is higher than that on the road side. Therefore, in the example shown in FIG. 4A, the boundary line candidate detection function detects the boundary line between the road surface and the road side as the first boundary line candidate and the third boundary line candidate based on the vertical polarization image. be able to. Further, since the temperature differs between the shade and the sun, the intensity of the vertically polarized signal and the horizontally polarized signal often differs between the shade and the sun. For example, as shown in FIGS. 4A and 4B, the intensity of the vertically polarized signal and the horizontally polarized signal in the sun is higher than in the shade. Therefore, in the example shown in FIGS. 4A and 4B, the boundary line candidate detection function uses the second boundary line as the boundary line between the shade and the sun based on the vertical polarization image and the horizontal polarization image. Can be detected as a candidate. Therefore, the first boundary line candidate and the second boundary line candidate are detected by intersecting, and the second boundary line candidate and the third boundary line candidate are detected by intersecting. Further, since the first boundary line candidate and the third boundary line candidate are boundary lines between the road surface and the road side, the second boundary line candidate is detected so as to straddle the road surface and the road side.

  The determination line setting function of the processing device 120 sets a determination line for determining whether or not the boundary line candidate is a road boundary line on the vertical polarization image and the horizontal polarization image. For example, the determination line setting function can set a determination line at a position where the boundary line candidate is moved by several pixels toward the installation position of the antenna device 110. For example, in the example shown in FIGS. 4A and 4B, the determination line setting function moves the first boundary line candidate by several pixels to the installation position side (X-axis positive direction side) of the antenna device 110. The determination line of the first boundary line candidate can be set as the first determination line at the position. In addition, the determination line setting function sets the second boundary line candidate determination line to the position where the second boundary line candidate is moved by several pixels to the installation position side (Y-axis negative direction side) of the antenna device 110. 2 determination lines can be set. Similarly, the determination line setting function can set the determination line of the third boundary line candidate, but only the first determination line and the second determination line will be described below for convenience of description.

  The road surface determination function of the processing device 120 determines the road surface of the road on the vertical polarization image and the horizontal polarization image by determining whether the boundary line candidate is a road surface boundary line. First, the road surface determination function is based on the vertical polarization signal and horizontal polarization signal of each pixel on the determination line, and the ratio (vertical) of the intensity of the vertical polarization signal and the horizontal polarization signal of each pixel on the determination line. (Polarization signal intensity / horizontal polarization signal intensity). The road surface determination function calculates the average intensity of the vertical polarization signal and horizontal polarization signal of each pixel on the determination line based on the vertical polarization signal and horizontal polarization signal of each pixel on the determination line.

  5 shows the ratio R between the intensity of the vertical polarization signal and the intensity of the horizontal polarization signal in the first determination line and the second determination line shown in FIG. 4, and the average intensity of the vertical polarization signal and the horizontal polarization signal. An example of V is shown. In the graph shown in FIG. 5, the vertical axis is the ratio R of the intensity of the vertical polarization signal and the intensity of the horizontal polarization signal, and the horizontal axis is the average intensity V of the vertical polarization signal and the horizontal polarization signal. , The pixels on the decision line are plotted. Further, in the graph shown in FIG. 5, continuous pixels on the determination line are connected by a line.

  With reference to FIG. 5, the ratio R between the intensity of the vertically polarized signal and the intensity of the horizontally polarized signal will be described. When there is a determination line on the same road surface as the first determination line shown in FIGS. 4A and 4B, it has come from the object on the closest side (the Y axis negative direction side in FIG. 4). In the pixel corresponding to the received wave (for example, the pixel on the first determination line (A part) shown in FIG. 5), the pixel corresponding to the received wave arriving from the object on the far side (Y-axis positive direction side in FIG. 4). Compared to (for example, the pixel of the first determination line (B part) shown in FIG. 5), the intensity of the horizontally polarized signal is increased, and the ratio R (vertical) between the intensity of the vertically polarized signal and the intensity of the horizontally polarized signal The polarization signal intensity / horizontal polarization signal intensity) tend to be small. As described above, the ratio V between the intensity of the vertically polarized signal and the intensity of the horizontally polarized signal on the determination line on the same road surface changes according to the distance from the own vehicle (antenna device 110) to the object. However, the ratio V between the intensity of the vertically polarized signal and the intensity of the horizontally polarized signal on the determination line on the same road surface changes according to the distance from the own vehicle (antenna device 110) to the object as described above. However, as shown in FIG. 5, it tends to be within the road surface area.

  On the other hand, as shown in FIGS. 5A and 4B, the second decision lines (A part and C part) shown in FIGS. The ratio R to the intensity of the horizontally polarized signal tends to be around 1. Thus, in the roadside determination line, the ratio R between the intensity of the vertical polarization signal and the intensity of the horizontal polarization signal tends to be a roadside area having a higher value of the ratio R than the road surface area. Therefore, in the example shown in FIG. 5, among the second determination lines straddling the road surface and the road side, for the second determination line (B part) of the road surface, the intensity of the vertical polarization signal and the intensity of the horizontal polarization signal The ratio R is plotted in the road area, and for the second determination line (A part and C part) on the road side, the ratio R between the intensity of the vertical polarization signal and the intensity of the horizontal polarization signal is plotted in the road area. ing.

  As described above, the road surface and the roadside tend to have different regions in which the ratio R between the intensity of the vertically polarized signal and the intensity of the horizontally polarized signal is plotted. Therefore, based on the ratio R between the intensity of the vertical polarization signal and the intensity of the horizontal polarization signal, it is determined whether the determination line is on the same road surface or straddles the road surface and the road side. It may be possible to determine whether the boundary line candidate corresponding to is a road boundary line or a boundary line between shade and sun. However, as in the first determination line (B part) and the second determination line (A part) shown in FIG. 5, the ratio R between the intensity of the vertical polarization signal and the intensity of the horizontal polarization signal is within the roadside region. In some cases, it is difficult to clearly determine whether there is a roadside area, and the determination line is on the same road surface only by the ratio R between the intensity of the vertically polarized signal and the intensity of the horizontally polarized signal. It may be difficult to determine whether there is a road surface and the road side. Therefore, in this embodiment, as will be described later, by determining the rate of change of the ratio R between the intensity of the vertical polarization signal and the intensity of the horizontal polarization signal along the determination line, whether the determination line is on the same road surface. Whether to straddle the road surface and the road side is determined.

  Next, the average intensity V of the vertically polarized signal and the horizontally polarized signal will be described. The average intensity V of the vertical polarization signal and the horizontal polarization signal tends to increase as the radiation temperature of the object increases. Therefore, as shown in FIG. 5, in the first determination line straddling the shade and the sun, the average intensities V of the vertical polarization signal and the horizontal polarization signal are compared in the first determination line (A part) in the shade. The average intensity V of the vertical polarization signal and the horizontal polarization signal becomes relatively large at the first determination line (B part) in the sun. Moreover, in the 1st determination line (A part) shown in FIG. 5, the average intensity | strength V of a vertical polarized-wave signal and a horizontal polarized-wave signal becomes large, so that it approaches the daylight.

  On the other hand, when the determination line straddles the road surface and the road side made of different materials as in the second determination line shown in FIG. 5, the vertical polarization signal and the horizontal polarization signal are generated on the road surface and the road side. In some cases, the average intensity V of the nuclei differs greatly. In particular, there is a case where the average intensity V of the vertically polarized signal and the horizontally polarized signal changes greatly at a displacement point that becomes a boundary between the road surface and the road side. For example, in the example shown in FIG. 5, at the AB displacement point of the second determination line, which is the displacement point between the second determination line (B part) on the road surface and the second determination line (A part) on the road side, The average intensity V of the polarization signal and the horizontal polarization signal changes greatly.

  Here, as shown in FIG. 5, the vertical polarization signal and the horizontal polarization at the displacement point of the first determination line (the displacement point between the first determination line (A part) and the first determination line (B part)). The change rate of the average intensity V of the signal is often less than the change rate according to the temperature difference (for example, 10 K) between the shade and the sun. On the other hand, since the AB displacement point of the second determination line is due to the second determination line straddling the road surface and the road side, the average of the vertical polarization signal and the horizontal polarization signal at the AB displacement point of the second determination line. The rate of change of the intensity V is larger than the rate of change of the average intensity V of the vertical polarization signal and the horizontal polarization signal at the displacement point of the first determination line, that is, the rate of change according to the temperature difference between the shade and the sun. There is a case. Therefore, in this embodiment, as will be described later, whether each determination line is based on the same road surface or whether the road surface and the road side are based on the change rate of the average intensity V between the vertical polarization signal and the horizontal polarization signal. It is judged whether it straddles.

  As described above, the road surface determination function includes the rate of change dR of the ratio R between the intensity of the vertically polarized signal and the intensity of the horizontally polarized signal, and the rate of change dV of the average intensity V between the vertically polarized signal and the horizontally polarized signal. Based on the above, it is determined whether each determination line is on the same road surface or straddles the road surface and the road side. Therefore, the road surface determination function first calculates the difference in the ratio R between the intensity of the vertical polarization signal and the intensity of the horizontal polarization signal between consecutive pixels among the pixels continuous along the determination line. The rate of change dR of the ratio R between the intensity of the signal and the intensity of the horizontally polarized signal is calculated. Similarly, the road surface determination function calculates the difference between the average intensities V of the vertical polarization signal and the horizontal polarization signal between the consecutive pixels among the continuous pixels along the determination line. Is calculated as the rate of change dV of the average intensity V.

  6 shows the rate of change dR of the ratio R between the intensity of the vertically polarized signal and the intensity of the horizontally polarized signal at the position along the first determination line shown in FIG. 4, and the vertically polarized signal and the horizontally polarized wave. It is a figure which shows an example of change rate dV of average intensity | strength V with a signal. 7 shows the rate of change dR of the ratio R between the intensity of the vertical polarization signal and the intensity of the horizontal polarization signal at the position along the second determination line shown in FIG. It is a figure which shows an example of change rate dV of average intensity V with a polarization signal. In the graphs shown in FIGS. 6 and 7, the vertical axis indicates the rate of change dR of the ratio R between the intensity of the vertical polarization signal and the intensity of the horizontal polarization signal, and the horizontal axis indicates the vertical polarization signal. The rate of change dV of the average intensity V between the horizontal polarization signal and the horizontal polarization signal is shown.

  As in the first determination line (A part) shown in FIG. 5, the ratio between the intensity of the vertical polarization signal and the intensity of the horizontal polarization signal of the pixel corresponding to the closest object even on the determination line on the same road surface. R varies greatly. Therefore, in the first determination line (part A) shown in FIG. 6, the rate of change dR of the ratio R between the intensity of the vertical polarization signal and the intensity of the horizontal polarization signal is large in the pixel corresponding to the closest object. ing. On the other hand, the change rate dR of the ratio R between the intensity of the vertical polarization signal and the intensity of the horizontal polarization signal in the pixel corresponding to the distant object as in the first determination line (B part) shown in FIG. It is getting smaller.

  On the other hand, as in the second determination line shown in FIG. 5, in the determination line straddling the road surface and the road side, the ratio R between the intensity of the vertical polarization signal and the intensity of the horizontal polarization signal is greatly different between the road surface and the road side. The ratio R between the intensity of the vertically polarized signal and the intensity of the horizontally polarized signal greatly changes at the displacement point that changes from the road surface to the road side. Therefore, in the second determination line shown in FIG. 7, the rate of change dR of the ratio R between the intensity of the vertical polarization signal and the intensity of the horizontal polarization signal is large at the AB displacement point that changes from the road surface to the road side.

  The rate of change dR of the ratio R between the intensity of the vertical polarization signal and the intensity of the horizontal polarization signal in the first determination line (A part) shown in FIG. 6 and the vertical polarization signal in the second determination line shown in FIG. When comparing the rate of change dR of the ratio R between the intensity and the intensity of the horizontally polarized signal, the second determination line shown in FIG. 7 is compared with the first determination line (A part) shown in FIG. The rate of change dR of the ratio R between the intensity of the vertically polarized signal and the intensity of the horizontally polarized signal at the AB displacement point that changes to the roadside is larger. Specifically, in the first determination line (A part) shown in FIG. 6, the change rate dR of the ratio R between the intensity of the vertical polarization signal and the intensity of the horizontal polarization signal corresponds to the closest object. Is also within the first determination range from the threshold value Sdx to the threshold value −Sdx. On the other hand, in the second determination line shown in FIG. 7, the rate of change dR of the ratio R between the intensity of the vertical polarization signal and the intensity of the horizontal polarization signal exceeds the first determination range from the threshold value Sdx to the threshold value −Sdx. Yes.

  Here, the threshold values Sdx and -Sdx are determined by the ratio R of the intensity of the vertically polarized signal and the intensity of the horizontally polarized signal on the determination line on the same road surface, the received noise, the refractive index of the received wave, the antenna element 111, 112 is an upper limit value and a lower limit value of the rate of change dR when it changes depending on the depression angle of the received wave received by 112 and the resolution of the array antenna 113, and the refractive index of the received wave and the received wave received by the antenna elements 111 and 112. It can be calculated based on at least one of the depression angle and the resolution of the array antenna 113. For example, when the depression angle of the received wave received by the antenna elements 111 and 112 is 10 °, SdX and −SdX can be set to 0.1 and −0.1, respectively.

  As a result, the road surface determination function has a rate of change dR of the ratio R between the intensity of the vertical polarization signal and the intensity of the horizontal polarization signal from the threshold value Sdx to the threshold value −Sdx, as indicated by the first determination line shown in FIG. In the first determination range, the change dR in the ratio R between the intensity of the vertically polarized signal and the intensity of the horizontally polarized signal is the refractive index of the received wave and the received wave received by the antenna elements 111 and 112. And the determination line is determined to be on the same road surface. On the other hand, as indicated by the second determination line shown in FIG. 7, the rate of change dR of the ratio R between the intensity of the vertically polarized signal and the intensity of the horizontally polarized signal indicates the first determination range from the threshold value Sdx to the threshold value −Sdx. In the case of exceeding, the change in the ratio R between the intensity of the vertically polarized signal and the intensity of the horizontally polarized signal is caused by the refractive index of the received wave, the depression angle of the received wave received by the antenna elements 111 and 112, and the array antenna 113. It is determined that the change is from the road surface to the road side, not from the resolution, and the determination line is determined to straddle the road surface and the road side.

  Further, as shown in FIG. 6, in the first determination line on the same road surface, at the displacement point where the determination line (A part) in the shade changes to the determination line (B part) in the sun, the vertical deviation is detected. The rate of change dV of the average intensity V of the wave signal and the horizontally polarized signal is large. Further, as shown in FIG. 7, in the second determination line straddling the road surface and the road side, the change rate dV of the average intensity V of the vertical polarization signal and the horizontal polarization signal at the AB displacement point changing from the road surface to the road side is as follows. It is getting bigger.

  The rate of change dV of the average intensity V of the vertical polarization signal and the horizontal polarization signal in the first determination line shown in FIG. 6, and the average intensity V of the vertical polarization signal and the horizontal polarization signal in the second determination line shown in FIG. Is compared with the first determination line shown in FIG. 6, the change rate dV of the average intensity V of the vertical polarization signal and the horizontal polarization signal is higher in the second determination line shown in FIG. 7 than in the first determination line shown in FIG. 6. It is getting bigger. Specifically, in the first determination line shown in FIG. 6, the rate of change dV of the average intensity V of the vertical polarization signal and the horizontal polarization signal is within the second determination range equal to or less than the threshold SK. On the other hand, in the second determination line shown in FIG. 7, the rate of change dV of the average intensity V of the vertical polarization signal and the horizontal polarization signal exceeds the second determination range equal to or less than the threshold SK.

  Here, in this embodiment, the temperature difference K between the shade and the sun on the same road surface is set as the threshold value SK. Further, since the temperature difference K between the shade and the sun on the same road surface changes according to the air temperature, the threshold value SK can also be set variably according to the air temperature. Further, the temperature difference K + α between the shade and the sun on the same road surface can be set as the threshold value SK.

  Therefore, the road surface determination function is used when the rate of change dV of the average intensity V of the vertical polarization signal and the horizontal polarization signal is within the second determination range equal to or less than the threshold SK, as indicated by the first determination line shown in FIG. Therefore, it is determined that the rate of change dV of the average intensity V of the vertical polarization signal and the horizontal polarization signal has changed from shade to sunlight, and the determination line is determined to be on the same road surface. On the other hand, the road surface determination function is used when the rate of change dV of the average intensity V of the vertical polarization signal and the horizontal polarization signal exceeds the second determination range equal to or less than the threshold SK, as indicated by the second determination line shown in FIG. Is determined that the change in the average intensity V of the vertical polarization signal and the horizontal polarization signal is not due to a change from shade to shade, but due to a change from the road surface to the roadside. It can be determined that the vehicle crosses the road surface and the road side.

  As described above, in this embodiment, in each determination line, the rate of change dR of the ratio R between the intensity of the vertical polarization signal and the intensity of the horizontal polarization signal, or the average of the vertical polarization signal and the horizontal polarization signal Whether the change rate dV of the intensity V is within the determination region formed by the first determination range from the threshold value Sdx to -Sdx and the second determination range equal to or less than the threshold value SK, as shown in FIGS. It is determined whether the determination line is on the same road surface or straddles the road surface and the road side.

  However, as shown in FIG. 8, when the boundary line between the shade and the sun is present in parallel with the road, the boundary line between the shade and the sun does not straddle the road surface and the road side. It is difficult to determine that the boundary between shade and sun is not a road boundary. Therefore, as shown in FIG. 9, the road surface determination function, when detecting three or more boundary line candidates that do not intersect each other in the vertical polarization image and the horizontal polarization image, The boundary line and the boundary line between the shade and the sun are determined. 9A is a diagram showing an example of a vertically polarized image in the scene shown in FIG. 8, and FIG. 9B is a diagram showing an example of a horizontally polarized image in the scene shown in FIG. is there.

  That is, when there are three or more boundary line candidates that do not intersect with each other, the determination line setting function first sets determination lines on both sides across each boundary line candidate, as shown in FIGS. 10 (A) and 10 (B). . For example, in the example shown in FIGS. 10A and 10B, the determination line setting function sets the first parallel determination lines 1a and 1b parallel to the first boundary line candidate on both sides straddling the first boundary line candidate. . Similarly, the determination line setting function sets second parallel determination lines 2a and 2b parallel to the first boundary line candidate on both sides of the second boundary line candidate. Although not shown, the determination line setting function sets third parallel determination lines 3a and 3b parallel to the first boundary line candidate on both sides straddling the third boundary line candidate.

  Here, for the first parallel determination lines 1a and 1b and the second parallel determination lines 2a and 2b, as shown in FIG. 5, the ratio R between the intensity of the vertical polarization signal and the intensity of the horizontal polarization signal is vertical. When the average intensity V of the polarization signal and the horizontal polarization signal is plotted, since the first parallel determination line 1a is on the road side, it is plotted in the roadside region shown in FIG. On the other hand, since the first parallel determination line 1b and the second parallel determination lines 2a and 2b are on the road surface, they are plotted in the road surface region shown in FIG. Therefore, the ratio R between the intensity of the vertical polarization signal and the intensity of the horizontal polarization signal, and the average intensity V of the vertical polarization signal and the horizontal polarization signal are set to the first parallel determination lines 1a and 1b and the second parallel determination. By comparing each of the lines 2a and 2b, it may be possible to determine whether the boundary line candidate corresponding to each determination line is a road boundary line or a boundary line between shade and sun. However, the farther away from the installation position of the antenna device 110, the lower the detection accuracy of the vertical polarization signal and the horizontal polarization signal, and it is determined whether the parallel determination line corresponds to the road surface or the road side. It can be difficult.

  Therefore, the determination line setting function sets a plurality of orthogonal determination lines orthogonal to each boundary line candidate at predetermined intervals. For example, as shown in FIGS. 10A and 10B, the determination line setting function can set a plurality of orthogonal determination lines L1 to Ln orthogonal to the second boundary line candidate. Although not shown, the determination line setting function can set a plurality of orthogonal determination lines orthogonal to the respective boundary line candidates for the first boundary line candidate and the third boundary line candidate.

  The road surface determination function includes a ratio R between the intensity of the vertical polarization signal and the intensity of the horizontal polarization signal, and the vertical polarization signal at a pixel where the parallel determination line and the orthogonal determination line of each boundary line candidate intersect. And the average intensity V of the horizontally polarized signal is calculated. For example, in the example shown in FIGS. 10A and 10B, the road surface determination function is a pixel in which the second parallel determination lines 2a and 2b of the second boundary line intersect with the second orthogonal determination lines L1 to Ln, respectively. , The ratio R between the intensity of the vertical polarization signal and the intensity of the horizontal polarization signal and the average intensity V of the vertical polarization signal and the horizontal polarization signal are calculated.

  Specifically, the road surface determination function is a ratio R between the intensity of the vertical polarization signal and the intensity of the horizontal polarization signal in the pixels on the same orthogonal determination line among the pixels where the parallel determination line and the orthogonal determination line intersect. Is calculated as the rate of change dR of the ratio R between the intensity of the vertically polarized signal and the intensity of the horizontally polarized signal at the positions on both sides across the boundary line candidate. Similarly, the road surface determination function calculates a difference between the average intensities V of the vertical polarization signal and the horizontal polarization signal in pixels on the same orthogonal determination line among the pixels where the parallel determination line intersects with the orthogonal determination line. It is calculated as the rate of change dV of the average intensity V of the vertical polarization signal and the horizontal polarization signal at the positions on both sides across the candidate.

  For example, in the example shown in FIGS. 10A and 10B, the road surface determination function performs the vertical polarization signal intensity and horizontal polarization in the pixel where the second parallel determination line 2a and the second orthogonal determination line L1 intersect. The difference between the ratio R of the signal intensity and the ratio R of the intensity of the vertical polarization signal and the intensity of the horizontal polarization signal in the pixel where the second parallel determination line 2b and the second orthogonal determination line L1 intersect, It is calculated as the rate of change dR of the ratio R between the intensity of the vertical polarization signal and the intensity of the horizontal polarization signal in the second orthogonal determination line L1. Further, the road surface determination function includes an average intensity V of the vertical polarization signal and the horizontal polarization signal in a pixel where the second parallel determination line 2a and the second orthogonal determination line L1 intersect, and an orthogonal determination with the second parallel determination line 2b. The difference between the average intensity V of the vertical polarization signal and the horizontal polarization signal in the pixel intersecting with the line L1 is expressed as the rate of change dV of the average intensity V of the vertical polarization signal and the horizontal polarization signal in the second orthogonal determination line L1. Calculate as Similarly, for the other orthogonal determination lines L2 to Ln, the road surface determination function also includes the rate of change dR of the ratio R between the intensity of the vertical polarization signal and the intensity of the horizontal polarization signal, the vertical polarization signal, and the horizontal polarization. The change rate dV of the average intensity V of the signal is calculated.

  FIG. 11 shows the rate of change dR of the ratio R between the intensity of the vertically polarized signal and the intensity of the horizontally polarized signal in the orthogonal decision lines L1 to Ln of the second boundary line candidates shown in FIG. It is a figure which shows an example with the change rate dV of the average intensity | strength V of a wave signal and a horizontal polarization signal. As shown in FIGS. 8 and 10, among the second boundary line candidates, the second determination line 2a is a determination line in the shade, and the second determination line 2b is a determination line in the sun. In the example shown in FIG. 11, the rate of change dV of the average intensity V of the vertical polarization signal and the horizontal polarization signal on each orthogonal determination line L1 to Ln is large to some extent due to the temperature difference between the shade and the sun on the same road surface. However, it falls within the second determination range equal to or less than the threshold value SK set based on the temperature difference between the shade and the sun on the same road surface. Further, since both the second determination line 2a and the second determination line 2b are on the same road surface, the rate of change dR of the ratio R between the intensity of the vertical polarization signal and the intensity of the horizontal polarization signal is small, and a value near zero. It becomes.

  Therefore, in the example shown in FIG. 11, the road surface determination function has a rate of change dR of the ratio R between the intensity of the vertical polarization signal and the intensity of the horizontal polarization signal in the orthogonal determination lines L1 to Ln of the second boundary line candidates. The change rate dV of the average intensity V of the vertical polarization signal and the horizontal polarization signal is determined to be within the first determination range and the second determination range, respectively, and within the determination region. Thereby, the road surface determination function can determine that the second boundary line candidate is a boundary line between the shade and the sun on the same road surface.

  The road surface determination function can determine the road surface of the road by determining whether each boundary line candidate is a road boundary line or a boundary line between the shade and the sun. For example, in the example shown in FIG. 4, the road surface determination function is such that the first boundary line candidate and the third boundary line candidate are boundary lines of the road surface, and the second boundary line candidate is a boundary line between the shade and the sun. By determining, it can determine with the area | region between a 1st boundary line candidate and a 3rd boundary line candidate being a road surface. In the example shown in FIG. 10, the road surface determination function is such that the first boundary line candidate and the third boundary line candidate are boundary lines of the road surface, and the second boundary line candidate is a boundary line between the shade and the sun. By determining, it can determine with the area | region between a 1st boundary line candidate and a 3rd boundary line candidate being a road surface.

  Subsequently, a road surface detection process according to the present embodiment will be described with reference to FIGS. 12 and 13. 12 and 13 are flowcharts showing the road surface detection process according to the present embodiment. Note that the road surface detection process described below is executed by the processing device 120.

  First, in step S101, the vertical polarization signal and the horizontal polarization signal output from the antenna device 110 are acquired by the image generation function. Specifically, the image generation function acquires a vertical polarization signal corresponding to the intensity of the vertical polarization component from the first antenna element 111 included in the antenna array 113 of the antenna device 110, and horizontally acquires from the second antenna element 112. A horizontal polarization signal corresponding to the intensity of the polarization component is acquired.

  In step S102, the image generation function generates an imaging image based on the vertical polarization signal and horizontal polarization signal acquired in step S101. For example, in the scene shown in FIG. 3, the image generation function generates a vertical polarization image as shown in FIG. 4A based on the vertical polarization signal received by the first antenna element 111. Further, the image generation function generates a horizontal polarization image based on the horizontal polarization signal received by the second antenna element 112 as shown in FIG.

  In step S103, a boundary line candidate on the road surface is detected in the vertical polarization image and horizontal polarization image generated in step S102 by the boundary line candidate detection function. For example, the boundary line candidate detection function detects the first boundary line, the second boundary line, and the third boundary line from the vertical polarization image and the horizontal polarization image shown in FIGS. Can do.

  In step S104, the determination line setting function determines whether or not the road boundary candidates detected in step S103 intersect. As shown in FIGS. 4A and 4B, if the road surface boundary line candidates intersect, the process proceeds to step S105. On the other hand, as shown in FIGS. 9A and 9B, when the road boundary candidates do not intersect, the process proceeds to step S113 shown in FIG.

  In steps S <b> 105 to S <b> 112, a process of determining which of the intersecting boundary line candidates is a boundary line on the road surface is performed. First, in step S105, a determination line parallel to the road boundary candidate detected in step S103 is set by the determination line setting function. For example, in the example shown in FIGS. 4A and 4B, the determination line setting function includes a first determination line parallel to the first boundary line candidate, the second boundary line candidate, and the third boundary line candidate. Two determination lines and a third determination line can be set.

  In step S106, the ratio R between the intensity of the vertical polarization signal and the intensity of the horizontal polarization signal is calculated for each pixel on the determination line set in step S105 by the road surface determination function. In step S107, the average intensity V of the vertical polarization signal and the horizontal polarization signal is calculated for each pixel on the determination line set in step S105 by the road surface determination function. For example, as shown in FIG. 5, with respect to the first determination line and the second determination line shown in FIGS. 4 (A) and 4 (B), the road surface determination function includes the vertical polarization signal intensity and the horizontal polarization signal intensity. Ratio R and the average intensity V of the vertical polarization signal and the horizontal polarization signal can be calculated.

  In step S108, the road surface determination function continues along the determination line as shown in FIG. 6 based on the ratio R of the intensity of the vertical polarization signal and the intensity of the horizontal polarization signal calculated in step S106. The difference in the ratio R between the intensity of the vertical polarization signal and the intensity of the horizontal polarization signal between the pixels changes the ratio R between the intensity of the vertical polarization signal and the intensity of the horizontal polarization signal at the position along the determination line. Calculated as a rate dR. Further, in step S109, based on the average intensity V of the vertical polarization signal and horizontal polarization signal calculated in step S107 by the road surface determination function, as shown in FIG. The difference between the average intensities V of the vertical polarization signal and the horizontal polarization signal is calculated as the rate of change dV of the average intensity V of the vertical polarization signal and the horizontal polarization signal at the position along the determination line.

  In step S110, the rate of change dR of the ratio R between the intensity of the vertical polarization signal and the intensity of the horizontal polarization signal calculated in step S108, the vertical polarization signal calculated in step S109, and It is determined whether or not the rate of change dV of the average intensity V of the horizontally polarized signal is within a determination region that is within the first determination range and the second determination range, respectively. The change rate dR of the ratio R between the intensity of the vertical polarization signal and the intensity of the horizontal polarization signal, and the change rate dV of the average intensity V of the vertical polarization signal and the horizontal polarization signal are within the first determination range and If it is within the determination area that falls within the 2 determination range, the process proceeds to step S111, and the boundary line candidate corresponding to the determination line is determined to be a road boundary line by the road surface determination function. On the other hand, if the determination area is exceeded by exceeding the first determination range or the second determination range, the process proceeds to step S112, and the boundary line candidate corresponding to the determination line is determined not to be a road boundary line by the road surface determination function. Is done.

  For example, in the example shown in FIG. 6, the road surface determination function includes the rate of change dR of the ratio R between the intensity of the vertical polarization signal and the intensity of the horizontal polarization signal, and the vertical polarization signal and horizontal in the first determination line. It can be determined that the rate of change dV of the average intensity V of the polarization signal is within a determination region that is within the first determination range and the second determination range, respectively (step S110 = Yes). Therefore, the road surface determination function can determine that the first boundary line candidate corresponding to the first determination line is a road surface boundary line (step S111).

  In the example shown in FIG. 7, the road surface determination function includes a rate of change dR of the ratio R between the intensity of the vertical polarization signal and the intensity of the horizontal polarization signal, and the vertical polarization signal and the horizontal in the second determination line. When the rate of change dV of the average intensity V of the polarization signal exceeds the first determination range or the second determination range, respectively, it can be determined that it exceeds the determination region (step S110 = No). Therefore, the road surface determination function can determine that the second boundary line candidate corresponding to the second determination line is not a road surface boundary line (step S112).

  Further, proceeding to FIG. 13, in step S113, it is determined by the road surface determination function whether there are three or more boundary line candidates that do not intersect. As shown in FIG. 9, when there are three or more boundary line candidates that do not intersect, the process proceeds to step S114. On the other hand, if there are not three or more boundary line candidates that do not intersect, the process proceeds to step S123.

  In steps S114 to S121, a process of determining which of the three or more boundary line candidates that do not intersect with each other is a boundary line on the road surface is performed. First, in step S114, parallel determination lines parallel to the boundary line candidate are set on both sides of the boundary line candidate detected in step S103 by the determination line setting function. For example, as shown in FIGS. 10 (A) and 10 (B), the determination line setting function applies to each boundary line candidate on both sides of the first boundary line candidate, the second boundary line candidate, and the third boundary line candidate. Parallel parallel determination lines 1a, 1b, 2a, 2b, 3a, 3b can be set.

  In step S115, an orthogonal determination line that is orthogonal to each boundary line candidate is set by the determination line setting function. For example, in the example shown in FIGS. 10A and 10B, the determination line setting function can set orthogonal determination lines L1 to Ln that are orthogonal to the second boundary line candidates. Similarly, the determination line setting function can set orthogonal determination lines orthogonal to the first boundary line candidate and the third boundary line candidate.

  In step S116, by the road surface determination function, in the pixel where the parallel determination line set in step S114 and the orthogonal determination line set in step S115 intersect, the intensity of the vertical polarization signal and the intensity of the horizontal polarization signal are calculated. The ratio R is calculated. In step S117, the average intensity V of the vertical polarization signal and the horizontal polarization signal is calculated by the road surface determination function at the pixel where the parallel determination line and the orthogonal determination line intersect.

  In step S118, the road surface determination function calculates the rate of change dR of the ratio R between the intensity of the vertical polarization signal and the intensity of the horizontal polarization signal on the orthogonal determination line. In step S119, the road surface determination function calculates the rate of change dV of the average intensity V of the vertical polarization signal and horizontal polarization signal on the orthogonal determination line. For example, with respect to the second boundary line candidate shown in FIG. 10, the road surface determination function determines the intensity of the vertical polarization signal and the intensity of the horizontal polarization signal at the pixel at which the second parallel determination line 2a and the second orthogonal determination line L1 intersect. And the difference R between the intensity of the vertical polarization signal and the intensity of the horizontal polarization signal in the pixel where the second parallel determination line 2b and the second orthogonal determination line L1 intersect is expressed as the second orthogonal It can be calculated as the rate of change dR of the ratio R between the intensity of the vertically polarized signal and the intensity of the horizontally polarized signal in the determination line L1. Further, the road surface determination function includes an average intensity V of the vertical polarization signal and the horizontal polarization signal in a pixel where the second parallel determination line 2a and the second orthogonal determination line L1 intersect, and an orthogonal determination with the second parallel determination line 2b. The difference between the average intensity V of the vertical polarization signal and the horizontal polarization signal in the pixel intersecting with the line L1 is expressed as the rate of change dV of the average intensity V of the vertical polarization signal and the horizontal polarization signal in the second orthogonal determination line L1. Can be calculated as

  In step S120, the road surface determination function causes the rate of change dR of the ratio R between the intensity of the vertical polarization signal and the intensity of the horizontal polarization signal calculated in step S118, and the vertical polarization signal calculated in step S119 and It is determined whether or not the rate of change dV of the average intensity V of the horizontally polarized signal is within a determination region that is within the first determination range and the second determination range, respectively. Like the second determination line shown in FIG. 11, the rate of change dR of the ratio R between the intensity of the vertical polarization signal and the intensity of the horizontal polarization signal and the average intensity V of the vertical polarization signal and the horizontal polarization signal If the rate of change dV is within the determination region within the first determination range and the second determination range, the process proceeds to step S121, and the boundary line candidate corresponding to the determination line is determined by the road surface determination function. It is determined that On the other hand, when exceeding the determination region by exceeding the first determination range or the second determination range, respectively, the process proceeds to step S122, and the boundary line candidate corresponding to the determination line is not a boundary line of the road surface by the road surface determination function. Determined.

  In step S123, the road surface is determined by the road surface determination function. Specifically, the road surface determination function determines the road surface based on the determination result of the road surface boundary line in steps S111 and S112 and the determination result of the road surface boundary line in steps S121 and S122. The road surface determination function may be configured such that when only two non-orthogonal boundary line candidates are detected, these boundary line candidates are determined as road boundary lines and the road surface is determined.

  As described above, the road surface detection device 100 according to the present embodiment, when the boundary line candidate detected from the vertical polarization image and the horizontal polarization image intersects, on the determination line along the boundary line candidate, A ratio R between the intensity and the intensity of the horizontal polarization signal is calculated, and a change rate dR of the ratio R between the intensity of the vertical polarization signal and the intensity of the horizontal polarization signal at the position on the determination line is calculated. Then, when the rate of change dR of the ratio R is in the first determination range from the threshold value Sdx to the threshold value −Sdx, the boundary line candidate corresponding to this determination line is determined as the boundary line of the road surface. As a result, as shown in FIGS. 3 and 4, even when the boundary line between the shade and the sunlit road on the same road surface is detected as a road surface boundary line candidate, the boundary line candidate is a road surface boundary line. Or whether it is the boundary line between the shade and the sun, it is possible to appropriately determine the road surface.

  In the present embodiment, a boundary line candidate corresponding to the boundary line on the road surface is set by setting a determination line at a position on the image where the boundary line candidate is moved a predetermined distance to the installation position side of the antenna device 110. For, a decision line can be set on the road surface. As a result, it is possible to appropriately determine whether or not the boundary line candidate corresponding to the road surface boundary line is a road surface boundary line.

  Further, in the present embodiment, when the boundary line candidates intersect, the average intensity V of the vertical polarization signal and the horizontal polarization signal is calculated on the determination line along the boundary line candidate, and the vertical deviation at the position along the determination line is calculated. A rate of change dV of the average intensity V between the wave signal and the horizontally polarized signal is calculated. Then, when the rate of change dV of the average intensity V is within the second determination range equal to or less than the threshold value SK, the boundary line candidate corresponding to this determination line is determined as the road boundary line. As a result, as shown in FIGS. 3 and 4, even if the boundary line between the shade and the sun is detected as a road boundary candidate on the same road surface, the boundary candidate is a road boundary line. It is possible to more appropriately determine whether there is a boundary line between the shade and the sun, and it is possible to more appropriately determine the road surface.

  In addition, in this embodiment, when three or more boundary line candidates do not intersect each other, a parallel determination line parallel to the boundary line candidate and an orthogonal determination line orthogonal to the boundary line candidate are set, and orthogonal to the parallel determination line In the pixel where the determination line intersects, the ratio R of the intensity of the vertical polarization signal and the intensity of the horizontal polarization signal and the average intensity V of the vertical polarization signal and the horizontal polarization signal are calculated. Then, the difference in the ratio R between the intensity of the vertical polarization signal and the intensity of the horizontal polarization signal in the pixels on the same orthogonal determination line is expressed as the vertical polarization signal intensity and the horizontal polarization at the positions on both sides across the orthogonal determination line. It is calculated as the rate of change dR of the ratio R to the intensity of the wave signal. In addition, the difference between the average intensities V of the vertical polarization signal and the horizontal polarization signal in the pixels on the same orthogonal determination line is determined as the average intensity V of the vertical polarization signal and the horizontal polarization signal at the positions on both sides across the orthogonal determination line. The rate of change dV is calculated. As a result, as shown in FIG. 8, even when the boundary line between the shade and the sunlit does not straddle the road surface and the roadside, the boundary line candidate corresponding to the boundary line between the shade and the sunlit is the boundary of the road surface. It is possible to appropriately determine whether it is a line or a boundary line between the shade and the sun.

  Furthermore, in the present embodiment, the first antenna element 111 receives a reception wave of a vertical polarization component and outputs a vertical polarization signal, and the second antenna element 112 receives a reception wave of a horizontal polarization component and horizontally By outputting the polarization signal, it is possible to appropriately determine whether or not it is a road boundary line from the ratio between the intensity of the vertical polarization signal and the intensity of the horizontal polarization signal.

  The embodiment described above is described for facilitating the understanding of the present invention, and is 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.

  For example, in the above-described embodiment, when three or more boundary line candidates do not intersect, a configuration in which an orthogonal determination line orthogonal to each boundary line candidate is set is illustrated. However, the present invention is not limited to this configuration. An intersection determination line that intersects with the line candidate may be set, and a ratio between the intensity of the vertical polarization signal and the intensity of the horizontal polarization signal may be calculated at a position on the intersection determination line across the boundary line candidate.

  In the above-described embodiment, the configuration in which the processes of steps S114 to S122 illustrated in FIG. 13 are performed when there are three or more boundary line candidates that do not intersect with each other is illustrated. However, the configuration is not limited to this configuration. When there are one or more boundary line candidates that are not to be processed, the processing in steps S114 to S122 illustrated in FIG. 13 may be performed.

  The first antenna element 111 according to the above-described embodiment is the first antenna element of the present invention, the second antenna element 112 is the second antenna element of the present invention, the array antenna 113 is the array antenna of the present invention, and the antenna. The device 110 corresponds to the antenna device of the present invention, and the processing device 120 corresponds to the control unit of the present invention.

DESCRIPTION OF SYMBOLS 100 ... Road surface detection apparatus 110 ... Antenna apparatus 113 ... Array antenna 111 ... 1st antenna element 112 ... 2nd antenna element 120 ... Processing apparatus

Claims (8)

A first antenna element that receives a received wave in a first polarization direction coming from an object and outputs a first polarization signal, and reception in a second polarization direction that is different from the first antenna element An antenna device having an array antenna in which a second antenna element that receives a wave and outputs a second polarization signal is arranged two-dimensionally;
A method for controlling a road surface detection device that generates an image based on the first polarization signal and the second polarization signal acquired from the antenna device, and determines a road surface based on the image,
Detecting road boundary candidates from the image,
When the boundary line candidate intersects, a change rate of a ratio between the intensity of the first polarization signal and the intensity of the second polarization signal is calculated along the boundary line candidate, and the change rate of the ratio is The control method which determines the said boundary line candidate as the boundary line of a road surface when it exists in the 1st determination range. The control method according to claim 1, comprising:
On the image, a determination line is set at a position where the boundary line candidate is moved a predetermined distance to the installation position side of the antenna device, and the rate of change of the ratio along the determination line is within the first determination range. In some cases, the control method determines the boundary line candidate as a road boundary line. The control method according to claim 1 or 2, wherein
When the boundary line candidate intersects, an average intensity change rate of the first polarization signal and the second polarization signal is calculated along the boundary line candidate, and the average intensity change rate is a second determination. A control method for determining a boundary line candidate as a road boundary line when the boundary line candidate is within a range. A first antenna element that receives a received wave in a first polarization direction coming from an object and outputs a first polarization signal, and reception in a second polarization direction that is different from the first antenna element An antenna device having an array antenna in which a second antenna element that receives a wave and outputs a second polarization signal is arranged two-dimensionally;
A method for controlling a road surface detection device that generates an image based on the first polarization signal and the second polarization signal acquired from the antenna device, and determines a road surface based on the image,
Detecting road boundary candidates from the image,
When there is a boundary candidate that does not intersect, the rate of change of the ratio between the intensity of the first polarization signal and the intensity of the second polarization signal is calculated on both sides across the boundary candidate, and the change in the ratio The control method which determines the said boundary line candidate as the boundary line of a road surface when a rate exists in the 1st determination range. The control method according to claim 4, comprising:
When there is a boundary candidate that does not intersect, the average intensity change rate of the first polarization signal and the second polarization signal is calculated on both sides across the boundary candidate, and the average intensity change rate is 2. A control method for determining a boundary line candidate as a road boundary line when the boundary line candidate is within a determination range. A control method according to any one of claims 1 to 5,
The first antenna element mainly receives a reception wave of a vertically polarized component as a reception wave in the first polarization direction,
The control method in which the second antenna element mainly receives a reception wave of a horizontal polarization component as a reception wave in the second polarization direction. A first antenna element that receives a received wave in a first polarization direction coming from an object and outputs a first polarization signal, and reception in a second polarization direction that is different from the first antenna element An antenna device having an array antenna in which a second antenna element that receives a wave and outputs a second polarization signal is arranged two-dimensionally;
A road surface detection device comprising: a control unit that generates an image based on the first polarization signal and the second polarization signal acquired from the antenna device, and determines a road surface based on the image. ,
The controller is
Detecting road boundary candidates from the image,
When the boundary line candidate intersects, the rate of change of the ratio between the intensity of the first polarization signal and the intensity of the second polarization signal is calculated along the boundary line candidate, and the ratio is a first determination A road surface detection apparatus that determines that the boundary line candidate is a road boundary line when the boundary line candidate is within the range. A first antenna element that receives a received wave in a first polarization direction coming from an object and outputs a first polarization signal, and reception in a second polarization direction that is different from the first antenna element An antenna device having an array antenna in which a second antenna element that receives a wave and outputs a second polarization signal is arranged two-dimensionally;
A road surface detection device comprising: a control unit that generates an image based on the first polarization signal and the second polarization signal acquired from the antenna device, and determines a road surface based on the image. ,
The controller is
Detecting road boundary candidates from the image,
When there is a boundary candidate that does not intersect, the rate of change of the ratio between the intensity of the first polarization signal and the intensity of the second polarization signal is calculated on both sides across the boundary candidate, and the change in the ratio A road surface detection device that determines a boundary line candidate as a road boundary line when the rate is within a first determination range.