Driving assistance device

Abstract

The driving assist device of the present application detects information on the height of an object without impairing the degree of freedom of vehicle design. It is provided with: an acquisition processing section that acquires a distance to an object detected based on a result of transmitting a transmission wave and receiving a reception wave that is a reception wave according to a transmission wave returned by reflection of the object, and a reception level of the reception wave used to detect the distance; and a detection processing section that detects information on the height of the object based on a relationship between the distance and the reception level acquired by the acquisition processing section.

Description

Technical Field

[0001] This invention relates to driving assistance devices. Background Technology

[0002] Previously, techniques for detecting the height of objects present around a vehicle have been studied. One known technique involves placing multiple ultrasonic sensors at different height positions on the vehicle and using these sensors to transmit and receive ultrasonic waves to detect the height of objects.

[0003] Patent Document 1: Japanese Patent No. 6026948

[0004] However, the aforementioned existing technologies require multiple ultrasonic sensors to be placed at different height positions on the vehicle, which sometimes limits the freedom of vehicle design. Summary of the Invention

[0005] Therefore, one of the objectives of this disclosure is to provide a driver assistance device that can detect information about the height of an object without compromising the freedom of vehicle design.

[0006] As an example of this disclosure, a driving assistance device includes: an acquisition processing unit that acquires a distance to an object detected based on the result of transmitting a transmitted wave and receiving a received wave as a result of the transmitted wave returning based on the reflection of the transmitted wave at the object, and a received level of the received wave used to detect the distance; and a detection processing unit that detects information about the height of the object based on the relationship between the distance and the received level acquired by the acquisition processing unit.

[0007] Based on the structure described above, information about the height of an object can be detected based on the relationship between the distance to the object and the received wave level, without relying on the positions of the transmitting and receiving waves. Therefore, information about the object's height can be detected without compromising the freedom of vehicle design.

[0008] Based on the aforementioned driver assistance device, the detection processing unit uses the degree of change in the received signal level corresponding to the change in distance as a relationship to detect information about altitude. With this structure, information about altitude can be easily detected based on the degree of change in the received signal level.

[0009] Based on this, the detection processing unit detects a value representing the height, as information about the height, based on the received level at which the degree of change in received level begins to exceed a threshold as the distance decreases. With this structure, the value representing the height can be easily detected simply by determining the received level at which the degree of change in received level begins to exceed a threshold.

[0010] Furthermore, in the above-described structure that uses the degree of variation in received signal level to detect information about height, the distances acquired by the acquisition processing unit include multiple distances to the object detected based on the simultaneous transmission of multiple transmitted waves and the reception of multiple received waves as a result of the multiple transmitted waves returning based on reflection from the object. The received signal level acquired by the acquisition processing unit includes multiple received signal levels for each of the multiple received waves used to detect the multiple distances, and the detection processing unit uses the deviation of the multiple received signal levels relative to the average value of each distance as the degree of variation. According to this structure, by increasing the number of obtained detection results, the relationship between the distance to the object and the received signal level can be obtained in greater detail. Therefore, the accuracy of detecting information about height can be improved. Additionally, the deviation of the received signal level can be easily calculated.

[0011] Based on the aforementioned driving assistance device, the detection processing unit detects altitude information based on the relationship between distance and reception level obtained by the acquisition processing unit, and preset information regarding that relationship. With this structure, altitude information can be easily detected using the relationship between distance and reception level obtained by the acquisition processing unit and the preset information.

[0012] Based on this, the setting information includes a predetermined relationship between distance and reception level based on the value representing altitude. The detection processing unit detects altitude information by comparing the distance-reception level relationship obtained by the acquisition processing unit with the predetermined relationship. With this structure, altitude information can be easily detected simply by comparing the distance-reception level relationship obtained by the acquisition processing unit with the predetermined relationship.

[0013] Furthermore, based on this situation, the defined relationships include multiple pre-defined relationships corresponding to cases where the values ​​representing height belong to different ranges. The detection processing unit determines which of the multiple ranges the value representing height belongs to based on the relationship between distance and received level obtained by the acquisition processing unit and the comparison results with the multiple relationships. With this structure, information about height can be detected in more detail by determining which of the multiple ranges the value representing height belongs to.

[0014] Furthermore, based on the aforementioned structure that detects height information based on the relationship between distance and received signal level, the distance acquired by the acquisition processing unit includes multiple distances to the object detected as a result of substantially simultaneous transmission of multiple transmitted waves and reception of multiple received waves as a result of multiple transmitted waves returning based on reflection at the object. The received signal level acquired by the acquisition processing unit includes multiple received signal levels for each of the multiple received waves used to detect the multiple distances. With this structure, by increasing the number of obtained detection results, the relationship between the distance to the object and the received signal level can be obtained in greater detail. Therefore, the accuracy of height information detection can be improved. Attached Figure Description

[0015] Figure 1 This is an illustrative and schematic diagram showing the appearance of a vehicle equipped with the driving assistance system according to the first embodiment, viewed from above.

[0016] Figure 2 This is an example and schematic block diagram illustrating the general hardware structure of the ECU (Electronic Control Unit) and distance detection device constituting the driving assistance system according to the first embodiment.

[0017] Figure 3 This is an illustrative and schematic diagram used to explain the outline of the technique for detecting the distance of an object in the first embodiment.

[0018] Figure 4 This is an illustrative and schematic diagram used to explain the features that should be of interest in order to detect the height of an object in the first embodiment.

[0019] Figure 5 This is a block diagram illustrating and schematically demonstrating the functional parts of the driving assistance device according to the first embodiment.

[0020] Figure 6 This is a schematic diagram illustrating the relationship between the distance to the object and the received level of the received wave, as described in the first embodiment.

[0021] Figure 7 This is a flowchart illustrating an example of a process performed in the first embodiment to detect information about the height of an object.

[0022] Figure 8 This is an illustrative and schematic diagram used to explain the outline of the method for detecting information about the height of an object in the second embodiment.

[0023] Figure 9 This is an example and schematic diagram illustrating an example of a map (table) representing setting information according to the second embodiment.

[0024] Figure 10 This is a flowchart illustrating an example of a process performed in the second embodiment to detect information about the height of an object.

[0025] Explanation of reference numerals in the attached figures

[0026] 500, 510… Driving assistance devices; 501… Acquisition and processing unit; 502, 512… Detection and processing unit. Detailed Implementation

[0027] Hereinafter, embodiments and modifications of the present disclosure will be described with reference to the accompanying drawings. The structures of the embodiments and modifications described below, as well as the functions and effects produced by such structures, are merely examples, and the present invention is not limited to the following description.

[0028] <First Embodiment>

[0029] Figure 1 This is an example and schematic diagram showing the appearance of a vehicle 1 equipped with the object detection system according to the first embodiment, viewed from above.

[0030] As described below, the driving assistance system according to the first embodiment uses the detection of objects present around the vehicle 1 (e.g., described later). Figure 2 The system uses an onboard sensor system (onboard sonar) to provide information about the obstacle O shown to perform driving assistance for vehicle 1.

[0031] More specifically, such as Figure 1 As shown, the driving assistance system according to the embodiment includes an ECU (Electronic Control Unit) 100 as an on-board control device and distance detection devices 201 to 204 as on-board sonar. The ECU 100 is mounted inside a four-wheeled vehicle 1, which has a pair of front wheels 3F and a pair of rear wheels 3R, and the distance detection devices 201 to 204 are mounted on external equipment of the vehicle 1.

[0032] exist Figure 1 In the example shown, as an example, the distance detection devices 201 to 204 are provided at different positions along the width direction of the vehicle body 2, which is an external component of the vehicle 1, on the rear end (rear bumper). However, the positions of the distance detection devices 201 to 204 are not limited to... Figure 1 Examples are shown. For instance, distance detection devices 201 to 204 may be installed at the front end (front bumper) of the vehicle body 2, at the side of the vehicle body 2, or at two or more of the rear end, front end, and side.

[0033] Furthermore, in the embodiments, the distance detection devices 201 to 204 have the same hardware configuration and function. Therefore, for simplicity, the distance detection devices 201 to 204 will sometimes be collectively referred to as object detection device 200. Additionally, in the embodiments, the number of object detection devices 200 is not limited to [specific number missing]. Figure 1 Four as shown.

[0034] Figure 2 This is a block diagram illustrating an example and schematic representation of the hardware structure of the ECU 100 and the object detection device 200 constituting the driving assistance system according to the first embodiment.

[0035] like Figure 2 As shown, the ECU 100 has the same hardware structure as a typical computer. More specifically, the ECU 100 includes an input / output device 110, a storage device 120, and a processor 130.

[0036] Input / output device 110 is used to enable communication between ECU 100 and external devices (in...) Figure 1 The example shown illustrates the interface for sending and receiving information between the object detection device 200 and the object detection device 200.

[0037] Storage device 120 includes main storage devices such as ROM (Read Only Memory) and RAM (Random Access Memory), and / or auxiliary storage devices such as HDD (Hard Disk Drive) and SSD (Solid State Drive).

[0038] The processor 130 controls various processes executed in the ECU 100. The processor 130 includes a computing device such as a CPU (Central Processing Unit). The processor 130 reads and executes computer programs stored in the storage device 120 to implement various functions such as automatic parking.

[0039] In addition, such as Figure 2 As shown, the object detection device 200 includes a transceiver 210 and a control unit 220.

[0040] The transceiver 210 has an oscillator 211 made of a piezoelectric element or the like, and uses the oscillator 211 to perform the transmission and reception of ultrasonic waves.

[0041] More specifically, the transceiver 210 transmits ultrasonic waves generated by the vibration of the oscillator 211 as a transmitting wave, and receives the vibration of the oscillator 211 generated by the reflection of the transmitted ultrasonic waves from objects present around the vehicle 1 as a receiving wave. Figure 2In the example shown, an obstacle O set on the road surface RS is exemplified as the object reflecting the ultrasonic waves from transceiver 210.

[0042] In addition, Figure 2 The example shown illustrates a structure in which both transmitting and receiving waves are implemented by a single transceiver 210 with a single oscillator 211. However, the technique of this embodiment can also be applied to structures where, for example, the first oscillator for transmitting waves and the second oscillator for receiving waves are separately configured, and the transmitting and receiving structures are separated.

[0043] The control unit 220 has the same hardware structure as a typical computer. More specifically, the control unit 220 includes an input / output device 221, a storage device 222, and a processor 223.

[0044] Input / output device 221 is used to realize the connection between the control unit 220 and the external (in) Figure 1 The example shown illustrates the interface for transmitting and receiving information between ECU100 and transceiver 210.

[0045] Storage device 222 includes main storage devices such as ROM and RAM, and auxiliary storage devices such as HDD or SSD.

[0046] The processor 223 controls various processes executed in the control unit 220. The processor 223 includes an arithmetic unit such as a CPU. The processor 223 reads and executes computer programs stored in the storage device 333, thereby performing various functions.

[0047] Here, the object detection device 200 involved in the embodiment detects the distance to an object using a technique known as the so-called TOF (Time Of Flight) method. As detailed below, the TOF method is a technique that calculates the distance to an object based on the difference between the time point when a transmitted wave is sent (more specifically, the start of transmission) and the time point when a received wave is received (more specifically, the start of reception).

[0048] Figure 3 This is an illustrative and schematic diagram used to explain the outline of the technique for detecting the distance of an object in the first embodiment.

[0049] More specifically, Figure 3 This is a graph illustrating, in chart form, the time variation of the signal level (e.g., amplitude) of the ultrasonic wave transmitted and received by the object detection device 200 according to the first embodiment. Figure 3 In the chart shown, the horizontal axis corresponds to time, and the vertical axis corresponds to the signal level of the signal transmitted and received by the object detection device 200 via the transceiver 210 (oscillator 211).

[0050] exist Figure 3 In the diagram shown, the solid line L11 represents an example of the time-varying envelope of the signal level of the signal transmitted and received by the object detection device 200, i.e., the degree of vibration of the oscillator 211. From this solid line L11, it can be read that the oscillator 211 is driven to vibrate for a time Ta from time point t0, transmits the wave at time point t1, and then continues to vibrate based on inertia during the time Tb from time point t2. Therefore, in Figure 3 In the chart shown, time Tb corresponds to the so-called reverberation time.

[0051] For the solid line L11, at time point t4 after time Tp has elapsed from the start of transmitting the wave at time point t0, the vibration of oscillator 211 reaches a peak value exceeding (or exceeding) the predetermined threshold Th1 represented by the dotted line L21. This threshold Th1 is used to identify whether the vibration of oscillator 211 is caused by a receiver acting as the object being detected (e.g., an object receiving the vibration). Figure 2 The transmitted wave is generated by the received wave reflected back from the obstacle O shown, or by the receiver as a signal from an object outside the object being detected (e.g., an obstacle O). Figure 2 The received wave is generated by the reflection of the transmitted wave back from the road surface (RS) shown, and the value is preset.

[0052] In addition, Figure 3 The example shown is that the threshold Th1 is set to a constant value that does not change over time, but in the implementation, the threshold Th1 can also be set to a value that changes with the passage of time.

[0053] Here, vibrations with a peak value exceeding the threshold Th1 (or higher) can be considered as being generated by receiving a transmitted wave as a transmitted wave reflected back by an object being detected. On the other hand, vibrations with a peak value below the threshold Th1 (or insufficient) can be considered as being generated by receiving a transmitted wave as a transmitted wave reflected back by an object other than the object being detected.

[0054] Therefore, it can be read from the solid line L11 that the vibration of the oscillator 211 at time point t4 is generated by receiving the transmitted wave as a reflection of the object being detected.

[0055] Furthermore, in solid line L11, the vibration of oscillator 211 decays after time point t4. Therefore, time point t4 corresponds to the time point at which the received wave, which is the transmitted wave reflected back by the object being detected, is completed; in other words, it corresponds to the time point at which the transmitted wave last transmitted at time point t1 returns as the received wave.

[0056] Furthermore, in solid line L11, time point t3, which is the starting point of the peak value in time point t4, corresponds to the time point at which the received wave begins to be received as the transmitted wave reflected back by the object being detected; in other words, it corresponds to the time point at which the transmitted wave initially transmitted at time point t0 returns as the received wave. Therefore, in solid line L11, the time ΔT between time point t3 and time point t4 is equal to the time Ta, which is the transmission time of the transmitted wave.

[0057] Based on the above, in order to determine the distance to the object being detected using the Time-of-Flight (TOF) method, it is necessary to calculate the time Tf between the time point t0 when the transmitted wave begins to be sent and the time point t3 when the received wave begins to be received. This time Tf can be calculated by subtracting the time ΔT, which is equal to the transmission time Ta, from the time Tp, which is the difference between the time point t0 and the time point t4 when the signal level of the received wave exceeds the threshold Th1.

[0058] The time point t0 at which the transmitted wave begins to be transmitted can be easily determined as the time point at which the object detection device 200 starts operating, and the transmission time Ta of the transmitted wave is predetermined by setting, etc. Therefore, in order to determine the distance to the object to be detected by the TOF method, it is ultimately important to determine the time point t4 at which the signal level of the received wave reaches a peak exceeding the threshold Th1.

[0059] However, in the past, techniques for detecting not only the distance to objects existing around vehicle 1, but also information about the height of those objects have been studied. One known technique involves placing multiple ultrasonic sensors at different height positions on vehicle 1 and using these sensors to transmit and receive ultrasonic waves to detect information about the height of the object.

[0060] However, the aforementioned existing technology requires multiple ultrasonic sensors to be placed at different height positions of vehicle 1, thus limiting the design freedom of vehicle 1.

[0061] Therefore, the implementation focuses on features as described below, thereby enabling the detection of information about the height of an object without compromising the freedom of vehicle design.

[0062] Figure 4 This is an illustrative and schematic diagram used to explain the features that should be of interest in order to detect information about the height of an object in the first embodiment.

[0063] exist Figure 4 The example illustrates two paths for transmitting and receiving ultrasonic waves that can be formed between an object detection device 200 with a height H and an object 400 (obstacle O) with a height h (<H). Furthermore, in Figure 4In the example shown, the shaded area R corresponds to the directional range of the ultrasonic waves transmitted and received by the object detection device 200.

[0064] like Figure 4 As shown, the flight distance of the ultrasonic waves transmitted and received between the object detection device 200 and the object 400 varies depending on the location where the reflection occurs on the object 400. For example, in Figure 4 In the example shown, the length of the path from the object detection device 200 flying along arrow A411 to the object 400, and then returning to the object detection device 200 along arrow A412 after being reflected by the object 400, is different from the length of the path from the object detection device 200 flying along arrow A421 to the object 400, and then returning to the object detection device 200 along arrow A422 after being reflected by the object 400.

[0065] Here, the lengths of the multiple paths formed between the object detection device 200 and the object 400 depend on the distance between them. Therefore, when the object detection device 200 and the object 400 are sufficiently far apart, the difference in length between the multiple paths can be ignored. Thus, in this case, the relationship between the distance between the object detection device 200 and the object 400 and the received signal level (which is the signal level of the received wave reflected back to the object detection device 200 from the object 400) becomes substantially equal across the multiple paths. Furthermore, although figures are omitted, the same relationship can be obtained even when the height h of the object 400 is higher than the height H of the object detection device 200.

[0066] However, when the object detection device 200 and the object 400 are somewhat close, the length differences between the multiple paths formed between the object detection device 200 and the object 400 cannot be ignored. Therefore, in this case, the relationship between the distance between the object detection device 200 and the object 400 and the received signal level, which is the signal level of the received wave reflected back to the object detection device 200 after reflection at the object 400, becomes discrepancy between the multiple paths. Furthermore, although the illustration is omitted, the same relationship can be obtained even when the height h of the object 400 is higher than the height H of the object detection device 200.

[0067] Here, as Figure 4 As shown, when the height h of the object 400 is lower than the height H of the object detection device 200, if the object detection device 200 and the object 400 are close to a certain distance, the object 400 will correspondingly move out of the directional range R of the ultrasonic wave. Therefore, in this case, the received signal level, which is the signal level of the received wave that returns to the object detection device 200 after being reflected from the object 400, gradually decreases.

[0068] On the other hand, although the illustration is omitted, when the height h of the object 400 is higher than the height H of the object detection device 200, even if the object detection device 200 and the object 400 are close to each other, the object 400 will not correspondingly move out of the directional range R of the ultrasonic wave. Therefore, in this case, the received signal level, which is the signal level of the received wave that returns to the object detection device 200 after being reflected from the object 400, gradually increases.

[0069] Based on the features described above, the first embodiment achieves the following by means of the ECU 100: Figure 5 The driving assistance device 500 shown is used to detect the height of objects present around the vehicle 1.

[0070] Figure 5 This is a block diagram illustrating and schematically showing the functional parts of the driving assistance device 500 according to the first embodiment.

[0071] like Figure 5 As shown, the driving assistance device 500 according to the first embodiment includes an acquisition processing unit 501 and a detection processing unit 502.

[0072] Furthermore, in the first embodiment, Figure 5 The structure shown is the result of hardware and software cooperation; more specifically, it is the result of the processor 130 of ECU 100 reading a prescribed computer program (driving assistance program or altitude detection program) from storage device 120 and executing it. However, in the first embodiment, Figure 5 At least a portion of the structure shown can also be implemented using dedicated hardware (circuitry).

[0073] The acquisition processing unit 501 acquires the detection results from the object detection device 200. More specifically, the acquisition processing unit 501 acquires from the object detection device 200 the distance to the object detected by the aforementioned TOF method based on the result of transmitting a transmitted wave and receiving a received wave as a result of the transmitted wave returning based on the reflection of the transmitted wave at the object, and the received level of the received wave used to detect the distance.

[0074] Then, the detection and processing unit 502, based on the reference... Figure 4 The aforementioned features are used to detect information about the height of the object. That is, the detection processing unit 502 detects information about the height of the object based on the relationship between distance and received signal level obtained by the acquisition processing unit 501.

[0075] The relationship between the distance to the object and the received wave level obtained by the acquisition processing unit 501 can be used as, for example, the following: Figure 6 It can be represented by a chart like the one shown.

[0076] Figure 6 This is a schematic diagram illustrating the relationship between the distance to the object and the received level of the received wave, as described in the first embodiment.

[0077] More specifically, Figure 6 In Figure 4 The change in received signal level corresponding to the change in distance to the object, under the condition shown (i.e., when the height h of the object is less than the height H of the object detection device 200), is represented by the graph of solid line L601. Figure 6 In the chart shown, the horizontal axis corresponds to the distance to the object, and the vertical axis corresponds to the received voltage level.

[0078] For reference Figure 4 As already explained, the following characteristics are shown: when the height h of the object is less than the height of the object detection device 200, the relationship between the distance to the object and the received wave level differs depending on whether the object detection device 200 and the object are sufficiently far apart, when the object detection device 200 and the object are close to a certain extent, or when the object detection device 200 and the object are even closer.

[0079] For example, in Figure 6 In the example shown, when the object detection device 200 and the object are sufficiently far apart, the distance on the horizontal axis is exemplified as the interval X3, which is greater than D2; when the object detection device 200 and the object are close to a certain extent, the distance on the horizontal axis is exemplified as the interval X2, which is between D1 and D2; and when the object detection device 200 and the object are even closer, the distance on the horizontal axis is exemplified as the interval X1, which is between 0 and less than D1.

[0080] here, Figure 6 The example shown corresponds to a situation where the height h of the object is less than the height H of the object detection device 200. Therefore, in Figure 6 In the example shown, within the interval X1 where the closer the object and the object detection device 200 are, the further the object moves away from the directional range of the ultrasonic wave, the lower the received level on the vertical axis becomes as the distance on the horizontal axis decreases.

[0081] On the other hand, as mentioned above, when the height h of the object 400 is greater than the height H of the object detection device 200, the object will not leave the directional range of the ultrasonic waves even if the object and the object detection device 200 are close. Therefore, in this case, even when equivalent to Figure 6 The interval X1 shown is the same as the intervals X2 and X3, with the horizontal axis distance decreasing and the vertical axis received level increasing (illustration omitted).

[0082] Therefore, as vehicle 1 approaches the object, the distance between them increases according to... Figure 6 When the intervals X3, X2, and X1 are moved in sequence, if the movement changes to the stage of interval X1, the relationship between the height h of the object and the height H of the object detection device 200 can be easily detected.

[0083] However, in the first embodiment, it is desirable to detect information about the height h of the object at a stage earlier than the stage of interval X1.

[0084] Therefore, the first embodiment is in Figure 6 In the example shown, the focus is on the interval X2, which is a distance between D1 and D2 on the horizontal axis. This interval X2 represents a characteristic where the degree of variation in the received level on the vertical axis increases. Moreover, the magnitude of the received level on the vertical axis depends on the height h of the object.

[0085] Based on the above, the first embodiment monitors the distance to the object and the received wave level as follows: Figure 6 The relationship shown indicates the point at which the degree of change in the received level relative to distance begins to exceed a threshold. Therefore, in the first embodiment, at a stage earlier than interval X1, i.e., at interval X2, it detects whether there is an object with a height h less than the height H of the object detection device 200.

[0086] In addition, the first embodiment pre-sets a map (table) showing the correspondence between the received level when the degree of change begins to exceed a threshold and the height h of the object, and uses the map to detect the height h of the object based on the magnitude of the received level when the deviation begins to exceed the threshold.

[0087] Thus, in the first embodiment, the detection processing unit 502 uses the degree of change in the received level corresponding to the change in distance to detect information about the height h of the object. More specifically, the detection processing unit 502 detects a value representing the height of the object based on the received level when the degree of change in the received level corresponding to the decrease in distance begins to exceed a threshold.

[0088] However, if the transmission and reception of ultrasonic waves based on a single object detection device 200 and the detection distance can be performed at shorter time intervals, then even using only the detection results from a single object detection device 200, it is possible to obtain the distance and received signal levels as shown in the figure. Figure 6 The detailed relationship is shown. However, due to variations in the performance of the object detection device 200, it is sometimes impossible to perform ultrasonic wave transmission and reception and detection distance based on a single object detection device 200 at shorter time intervals. In this case, it is assumed that because the number of detection results obtained is reduced, the relationship between distance and received level can only be used as a relatively... Figure 6 The example shown is obtained from a loose set of points, which cannot detect deviations in the received level with high precision.

[0089] Therefore, the first embodiment increases the number of detection results obtained by transmitting transmission waves from multiple body detection devices 200 approximately simultaneously, thereby achieving the goal of obtaining distance and received level as shown in the figure. Figure 6 The detailed relationship is shown. In this case, in order to mutually identify the multiple ultrasonic waves transmitted and received by the multiple object detection devices 200, the multiple ultrasonic waves are encoded with mutually distinct identification information. As an encoding method, various methods such as phase modulation, frequency modulation, and combinations thereof can be used.

[0090] Furthermore, in the first embodiment, when the detection processing unit 502 obtains the relationship between distance and received level by transmitting transmitted waves from multiple object detection devices 200 approximately simultaneously, it can use the average difference of the multiple received levels obtained from the multiple object detection devices 200 as a deviation used as an indicator for the height h of the detected object. In this case, the detection processing unit 502 can also correct the multiple received levels based on the difference in the installation positions of the object detection devices 200 in the width direction of the vehicle 1.

[0091] On the other hand, in the first embodiment, when the detection processing unit 502 obtains the relationship between distance and reception level using only the detection result of one object detection device 200, it can use the deviation of the moving average relative to the reception level obtained by one object detection device 200 as the deviation used as an index for the height h of the detected object.

[0092] The detection processing unit 502 according to the first embodiment detects information about the height h of the object using the method described above. Then, in the first embodiment, the information about the height h detected by the detection processing unit 502 can be used for driving assistance in the vehicle 1.

[0093] For example, if the height h of the object detected by the detection processing unit 502 is less than the height H of the object detection device 200, it can be determined that the object is an object with a low probability of contacting the vehicle body 2, such as a wheel fastener. On the other hand, if the height h of the object detected by the detection processing unit 502 is greater than the height H of the object detection device 200, it can be determined that the object is an object with a high probability of contacting the vehicle body 2, such as a wall or pillar.

[0094] Therefore, the height h of the object detected by the detection processing unit 502 can be used to evaluate the likelihood of contact between the vehicle body 2 and the object when performing automatic parking, as an example of driving assistance. Therefore, in the first embodiment, the detection processing unit 502 outputs the detection result regarding the height h of the object to the automatic parking control function unit mounted on the vehicle 1. The automatic parking control function unit can be implemented by the ECU 100 that implements the driving assistance device 500, or by other ECUs.

[0095] Furthermore, it goes without saying that in the first embodiment, the detection results of information about the height h of the object can be used for other driving assistance (such as automatic parking) that are different from automatic parking.

[0096] Based on the above structure, the driving assistance device 500 according to the first embodiment performs the following functions. Figure 7 The processing is shown. Figure 7 The series of processes shown are repeatedly executed, for example, according to a prescribed control cycle.

[0097] Figure 7 This is an example and schematic flowchart illustrating the process performed in the first embodiment to detect information about the height h of an object.

[0098] like Figure 7 As shown, in the first embodiment, firstly, in S701, the acquisition processing unit 501 of the driving assistance device 500 acquires the detection results based on the object detection device 200, more specifically, the detection results of the distance to the object and the received level of the received wave used to detect the distance.

[0099] Then, in S702, the detection and processing unit 502 of the driver assistance device 500 calculates the deviation of the received level based on the relationship between the distance and the received level obtained in S701.

[0100] Then, in S703, the detection processing unit 502 determines whether the deviation calculated in S702 exceeds the threshold.

[0101] If S703 determines that the deviation does not exceed the threshold, the height h of the detected object cannot be determined. Therefore, in this case, the process ends while maintaining this state.

[0102] On the other hand, if it is determined in S703 that the deviation exceeds the threshold, the height h of the detected object can be obtained. Therefore, in this case, the process proceeds to S704 below.

[0103] In S704, the detection processing unit 502 bases the received level (e.g., when the deviation begins to exceed the threshold) on the received level. Figure 6In the example shown, the received level corresponds to the distance D2, and the height h of the detected object is used. In this case, for example, a pre-set image can be used as data representing the correspondence between the received level when the deviation begins to exceed the threshold and the height h of the object.

[0104] Then, in S705, the detection processing unit 502 outputs the detection result of height h from S704 to, for example, a function unit for controlling automatic parking mounted on vehicle 1. As a result, automatic parking of vehicle 1 is performed in an appropriate manner corresponding to the height h of the object. Then, the processing ends.

[0105] As explained above, the driving assistance device 500 according to the first embodiment includes an acquisition processing unit 501 and a detection processing unit 502. The acquisition processing unit 501 acquires from the object detection device 200 the distance to the object detected based on the transmission of a transmitted wave and the reception of a received wave as a result of the transmitted wave returning based on the reflection of the transmitted wave at the object, and the reception level of the received wave used to detect the distance. Then, the detection processing unit 502 detects information about the height h of the object based on the relationship between the distance and the reception level acquired by the acquisition processing unit 501.

[0106] Based on the structure described above, information about the height h of the object can be detected based on the relationship between the distance to the object and the received wave level, without relying on the positions of the transmitting and receiving waves. Therefore, information about the height h of the object can be detected without compromising the design freedom of vehicle 1.

[0107] More specifically, in the first embodiment, the detection processing unit 502 uses the degree of change in the received level corresponding to the distance change as the aforementioned relationship to detect information about the height h of the object. With this structure, information about the height h of the object can be easily detected based on the degree of change in the received level.

[0108] More specifically, in the first embodiment, the detection processing unit 502 detects the value of the height h of the object based on the reception level at which the degree of reception level variation corresponding to the decrease in distance begins to exceed a threshold, and uses this as information about the height h of the object. With this structure, the value of the height h of the object can be easily detected simply by determining the reception level at which the degree of reception level variation begins to exceed a threshold.

[0109] Furthermore, in the first embodiment, the distance acquired by the acquisition processing unit 501 may include multiple distances to the object detected based on the substantial simultaneous transmission of multiple transmitted waves and the reception of multiple received waves as a result of the multiple transmitted waves returning based on reflections at the object. The received levels acquired by the acquisition processing unit 501 may include multiple received levels of the multiple received waves used to detect the multiple distances respectively. Then, the detection processing unit 502 uses the deviation of the multiple received levels relative to the average value of each distance as the degree of variation described above. According to this structure, by increasing the number of obtained detection results, the relationship between the distance to the object and the received wave level can be obtained in more detail. Therefore, the accuracy of detecting information about the height of the object can be improved. Furthermore, the deviation of the received levels can be easily calculated.

[0110] <Second Implementation>

[0111] Furthermore, in the first embodiment described above, information about the height h of the object was detected by detecting the start of the received level deviation. However, as a second embodiment, a structure that detects information about the height h of the object before the start of the received level deviation can also be considered.

[0112] Furthermore, the second embodiment differs from the first embodiment only in the method for detecting information about the height h of the object; the basic hardware structure and functions are the same as the first embodiment. That is, the driving assistance device 510 according to the second embodiment includes a detection processing unit 512 (see reference 512) instead of the detection processing unit 502 according to the first embodiment. Figure 5 Except for this point, which is a functional part for detecting information about the height h of the object, it is implemented in the same way as in the first embodiment.

[0113] The method performed in the second embodiment to detect the height h of an object is common to the method performed in the first embodiment, based on the generalized technical concept of utilizing the relationship between distance and reception level obtained by the acquisition processing unit 501. However, in the second embodiment, as will be explained below, the method utilizing the relationship between distance and reception level obtained by the acquisition processing unit 501 differs from that in the first embodiment.

[0114] Figure 8 This is an illustrative and schematic diagram used to explain the outline of the method for detecting information about the height h of an object in the second embodiment.

[0115] like Figure 8 As shown, in the second embodiment, the same relationship as in the first embodiment is obtained (see reference). Figure 6The distance and the received level are obtained by the acquisition processing unit 501. In the first embodiment, a method is used to detect the height h of the object by focusing on the boundary between the intervals X2 and X3, which are the points where the received level begins to deviate. Therefore, if the distance to the object is not less than or equal to the distance D2, the height h of the object cannot be detected.

[0116] However, even within the interval X3 before the received level begins to deviate, the magnitude of the received level depends on the height h of the object. Therefore, in the second embodiment, information about the height h of the object is detected by comparing the relationship between distance and received level obtained by the acquisition processing unit 501 with a predetermined relationship between distance and received level set according to the value representing the height h of the object.

[0117] That is, in Figure 8 In the example shown, four relationships, L811, L812, L813, and L814, are predetermined as a comparison between the distance and the received level obtained by the acquisition processing unit 501.

[0118] For example, in Figure 8 In the example shown, the dotted line L811 corresponds to a predetermined relationship established through experiments, etc., corresponding to the first range where the object's height h is below h1 (>0). Similarly, the dotted line L812 corresponds to a predetermined relationship established through experiments, corresponding to the second range where the object's height h is above h1 and below h2. Furthermore, the dotted line L813 corresponds to a predetermined relationship established through experiments, corresponding to the third range where the object's height h is above h2 and below h3. And the dotted line L814 corresponds to a predetermined relationship established through experiments, corresponding to the fourth range where the object's height h is above h3 and below h4. Moreover, in the second embodiment, based on the relationships represented by the dotted lines L811 to L814, other relationships where the object's height h is above one or more ranges greater than h4 can also be predetermined.

[0119] exist Figure 8 In the example shown, the dotted line L811 can be used as a threshold Th811 to determine whether the height h of an object belongs to the first range mentioned above. That is, in Figure 8 In the example shown, if the distance-received level relationship obtained by the acquisition processing unit 501 (refer to solid line L601) is on the side with a smaller received level than the dotted line L811, it can be determined that the height h of the object belongs to the first range mentioned above.

[0120] Similarly, the dotted line L812 can be used as a threshold Th812 to determine whether the height h of an object belongs to the second range mentioned above. That is, in Figure 8In the example shown, if the distance-received level relationship obtained by the acquisition processing unit 501 (refer to solid line L601) is on the side with a larger receive level than dashed line L811 and a smaller receive level than dashed line L812, it can be determined that the height h of the object belongs to the second range mentioned above.

[0121] Additionally, the dashed line L813 can be used as a threshold Th813 to determine whether the height h of an object belongs to the third range mentioned above. That is, in Figure 8 In the example shown, if the relationship between distance and received level obtained by the acquisition processing unit 501 (refer to solid line L601) is on the side with a higher received level than dotted line L812 and a lower received level than dotted line L813, it can be determined that the height h of the object belongs to the third range mentioned above.

[0122] Additionally, the dashed line L814 can be used as a threshold Th814 to determine whether the height h of an object belongs to the fourth range mentioned above. That is, in Figure 8 In the example shown, if the distance-received level relationship obtained by the acquisition processing unit 501 (refer to solid line L601) is on the side with a larger receive level than dashed line L813 and a smaller receive level than dashed line L814, it can be determined that the height h of the object belongs to the fourth range mentioned above.

[0123] The comparison between the solid line L601 and the dotted lines L811 to L814 can also be performed in the interval X3 before the received level begins to deviate. Therefore, according to the second embodiment, information about the height h of the object can be detected before the received level begins to deviate.

[0124] The dotted lines L811 to L814, which represent the aforementioned setting information, are as follows: Figure 9 The image (table) 900 shown is pre-stored in storage device 120 (see reference). Figure 1 ).

[0125] Figure 9 This is an example illustration and schematic diagram showing a table 900 representing setting information related to the second embodiment.

[0126] like Figure 9 As shown, in the second embodiment, as setting information, a correspondence is pre-set between multiple ranges to which the height h of an object can belong (the first to fourth ranges mentioned above) and thresholds (thresholds Th811 to Th814 mentioned above) used to determine which of the multiple ranges the height h of an object belongs to.

[0127] Based on the above structure, in the second embodiment, in order to detect information about the height h of the object, the following is performed. Figure 10The processing is shown. Figure 10 The series of processes shown are repeated within a specified control cycle.

[0128] Figure 10 This is a flowchart illustrating an example of a process performed in the second embodiment to detect information about the height h of an object.

[0129] like Figure 10 As shown, in the second embodiment, firstly, in S1001, the acquisition processing unit 501 acquires the detection results based on the object detection device 200, and more specifically, acquires the detection results of the distance to the object and the received level of the received wave used to detect the distance.

[0130] Then, in S1002, the detection processing unit 512 compares the relationship between the distance and the received level obtained in S701 with preset setting information. For example, according to the above... Figure 8 In the example shown, the detection processing unit 512 compares the magnitude of the solid line L611, which represents the relationship between the distance and the received level obtained in S701, and the dotted lines L811 to L814, which represent the thresholds Th811 to Th814 preset as setting information, along the vertical axis.

[0131] Then, in S1003, the detection processing unit 512 detects the height h of the object based on the comparison result in S1002. For example, in the above... Figure 8 In the example shown, the solid line L611 is located between the dotted lines L812 and L813 in the vertical direction. Therefore, the detection processing unit 513 determines that the height h of the object belongs to the third range mentioned above corresponding to the dotted line L813.

[0132] Then, in S1004, the detection processing unit 512 outputs the detection height h from S1003 to, for example, a function unit for controlling automatic parking mounted on the vehicle 1. Thus, automatic parking of the vehicle 1 is performed in an appropriate manner corresponding to the height h of the object. Then, the processing ends.

[0133] As explained above, in the second embodiment, the detection processing unit 512 detects information about the height h of the object based on the relationship between distance and received signal level obtained by the acquisition processing unit 501. With this structure, information about the height h of the object can be detected based on the relationship between the distance to the object and the received signal level, independent of the positions of the transmitting and receiving waves. Therefore, information about the height h of the object can be detected without compromising the design freedom of the vehicle 1.

[0134] More specifically, in the second embodiment, the detection processing unit 512 checks information about the height h of the object based on the relationship between distance and reception level obtained by the acquisition processing unit 501 and setting information preset about that relationship. With this structure, information about the height h of the object can be easily detected using the relationship between distance and reception level obtained by the acquisition processing unit 501 and the setting information.

[0135] That is, the setting information includes a predetermined relationship between distance and reception level based on the value representing the height h of the object. Furthermore, the detection processing unit 512 detects information about the height h of the object based on a comparison between the distance-reception level relationship obtained by the acquisition processing unit 501 and the predetermined relationship. With this structure, information about the height h of the object can be easily detected simply by comparing the distance-reception level relationship obtained by the acquisition processing unit 501 with the predetermined relationship.

[0136] More specifically, the relationships specified above include multiple pre-defined relationships based on the case where the height h value of the represented object belongs to multiple different ranges (see reference). Figure 9 Therefore, the detection processing unit 512 determines which of the multiple ranges the value of the height h representing the object belongs to, based on the relationship between distance and received level obtained by the acquisition processing unit 501 and the comparison results with multiple relationships. With this structure, more detailed information about the height h of the object can be detected by determining which of the multiple ranges the value of the height h representing the object belongs to.

[0137] Furthermore, in the second embodiment, similar to the first embodiment, the distance acquired by the acquisition processing unit 501 may include multiple distances to the object detected as a result of substantially simultaneously transmitting multiple transmitted waves and receiving multiple received waves as a result of multiple transmitted waves returning based on reflections at the object. The received levels acquired by the acquisition processing unit 501 may include multiple received levels of the multiple received waves used to detect the multiple distances. With this structure, by increasing the number of obtained detection results, the relationship between the distance to the object and the received wave levels can be obtained in greater detail. Therefore, the accuracy of detecting information about the height h of the object can be improved.

[0138] <Variation Example>

[0139] Furthermore, the first and second embodiments described above can be implemented in combination. Therefore, the technology of this disclosure also includes, for example, the technology of the second embodiment to detect information about the height of an object before the received level begins to deviate, and the technology of the first embodiment to detect information about the height of an object after the received level begins to deviate.

[0140] Furthermore, in the first and second embodiments described above, the technology of this disclosure is applied to structures that detect the distance to an object by transmitting and receiving ultrasonic waves. However, the technology of this disclosure can also be applied to structures that detect the distance to an object by transmitting and receiving waves other than ultrasonic waves, such as radio waves, millimeter waves, radar, and electromagnetic waves.

[0141] The embodiments and modifications of this disclosure have been described above, but these embodiments and modifications are merely examples and are not intended to limit the scope of the invention. The new embodiments and modifications described above can be implemented in various ways, and various omissions, substitutions, and changes can be made without departing from the spirit of the invention. The embodiments and modifications described above are included within the scope and spirit of the invention, and are included within the scope of the invention as described in the claims and its equivalents.

Claims

1. A driving assist device characterized by comprising: Possessing: acquisition processing section, which acquires a distance to an object detected based on a result of transmitting a transmission wave and receiving a reception wave as a result of reflecting on the object, and a reception level of the reception wave used to detect the distance; and detection processing section, which detects information on a height of the object based on a relationship of the distance and the reception level acquired by the acquisition processing section, the detection processing section uses a degree of variation of the reception level corresponding to the distance variation as the relationship to detect the information on the height.

2. The driving assistance device according to claim 1, characterized in that the detection processing section detects a value indicating the height as the information on the height based on the reception level at a time when the degree of variation of the reception level corresponding to the distance becoming smaller starts to exceed a threshold value.

3. The driving assistance device according to claim 1, characterized in that the distance acquired by the acquisition processing section includes a plurality of distances to the object detected based on a result of transmitting a plurality of transmission waves substantially simultaneously and receiving a plurality of reception waves as a result of reflecting on the object, and the reception level acquired by the acquisition processing section includes a plurality of reception levels of the plurality of reception waves used to detect the plurality of distances, respectively, the detection processing section uses a deviation of the plurality of reception levels from an average value for each of the distances as the degree of variation.

4. The driving assistance device according to claim 2, characterized in that the distance acquired by the acquisition processing section includes a plurality of distances to the object detected based on a result of transmitting a plurality of transmission waves substantially simultaneously and receiving a plurality of reception waves as a result of reflecting on the object, and the reception level acquired by the acquisition processing section includes a plurality of reception levels of the plurality of reception waves used to detect the plurality of distances, respectively, the detection processing section uses a deviation of the plurality of reception levels from an average value for each of the distances as the degree of variation.

5. The driving assistance device according to any one of claims 1 to 4, characterized in that the detection processing section detects the information on the height based on the relationship of the distance and the reception level acquired by the acquisition processing section, and setting information set in advance with respect to the relationship.

6. The driving assistance device according to claim 5, characterized in that the setting information includes a prescribed relationship of the distance and the reception level set in advance according to a value indicating the height, the detection processing section detects the information on the height based on a comparison result of the relationship of the distance and the reception level acquired by the acquisition processing section and the prescribed relationship.

7. The driving assistance device according to claim 6, characterized in that the prescribed relationship includes a plurality of relationships set in advance corresponding to a case where the value indicating the height belongs to a plurality of ranges different from each other, respectively, The detection processing section detects which of the plurality of ranges the value indicating the height belongs to, based on the relationship between the distance and the reception level acquired by the acquisition processing section, and a comparison result of the plurality of relationships.

8. The drive assist device according to claim 5, characterized by The distance acquired by the acquisition processing section includes a plurality of distances to the object detected based on transmitting a plurality of transmission waves substantially simultaneously and receiving a plurality of reception waves as a result of the plurality of transmission waves returning from reflection by the object, and the reception level acquired by the acquisition processing section includes a plurality of reception levels of the plurality of reception waves used to detect the plurality of distances, respectively.

9. The drive assist device according to claim 6 or 7, characterized by The distance acquired by the acquisition processing section includes a plurality of distances to the object detected based on transmitting a plurality of transmission waves substantially simultaneously and receiving a plurality of reception waves as a result of the plurality of transmission waves returning from reflection by the object, and the reception level acquired by the acquisition processing section includes a plurality of reception levels of the plurality of reception waves used to detect the plurality of distances, respectively.

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