JP2015203600A - object detection system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect an object left on a road surface.SOLUTION: An object detection system (100) comprises: a sensor (903) that is attached to a vehicle (900) and repeatedly measures a distance from an attaching position to a road surface with a predetermined width as a scanning region (RD); and a notification part (902) for, when a preset variation is detected in the distance measured by the sensor, notifying a user of that.

Description

  The present invention relates to a technique for detecting an object.

When construction is performed on airport runways or taxiways, work is usually done at night without takeoff and landing. And after work, it is necessary to confirm whether tools or parts are left behind. This is because misplacement of tools or the like may interfere with the operation of the aircraft.
Conventionally, a large number of workers with lights lined up in a row, and slowly searched while checking whether there was any misplacement by visual observation, thereby searching the entire range of work. This confirmation work was very time-consuming.
In relation to this point, there is a technique for acquiring information about the surrounding environment such as the presence of an obstacle by installing a sensor in the vehicle in order to ensure the safety of traveling of the vehicle (Patent Documents 1 and 2). etc). According to such technology, other vehicles approaching, guardrails, and other structures that are likely to affect the safety of traveling and recognize the presence of relatively large objects Is possible. However, with such a technique, it is difficult to confirm whether or not a relatively small object such as a part is left on the road without being directly related to traveling safety.

Japanese Patent Laid-Open No. 05-205198 JP 2011-117895 A

  An object of the present invention is to detect an object left on a road surface.

In one aspect, the present invention provides a sensor that is attached to a vehicle and that measures a distance from an attachment position to a road surface using a predetermined width as a scanning region, and a preset change in the distance measured by the sensor. When detected, an object detection system having a notification unit for notifying the user of the occurrence of the change is provided.
In a preferred aspect, the sensor is mounted at a predetermined height from the road surface behind the vehicle.
In a preferred aspect, the apparatus further includes a measurement unit that measures the position of the vehicle and a designation unit that designates a search range, and the notification unit identifies a scanned region and an unscanned region in the search range. And display.
In another aspect, the present invention provides a step of repeatedly scanning a sensor that measures a distance from an attachment position to a road surface while driving a vehicle, using a predetermined width as a scanning region, and a distance measured by the sensor. And a step of notifying the user of the occurrence of the change when a preset change is detected.

  According to the present invention, an object left on the road surface is detected.

1 is a schematic diagram of an object detection system 100. FIG. 1 is a functional diagram of an object detection system 100. FIG. It is a figure which shows the control parameter of the detection part. 2 is a flowchart of the object detection system 100. FIG. It is an example of the screen displayed during a detection operation. It is a functional diagram of object detection system 100A. It is an example of the screen displayed when designating a target range. It is an example of the screen displayed during a detection operation. It is an example of the screen displayed during a detection operation.

FIG. 1 shows an outline of the object detection system 100. The object detection system 100 is attached to a vehicle 900 and includes a rotating lamp 902, a laser scanner 903, and a control device (not shown in FIG. 1) provided in the vehicle.
The vehicle 900 is an automobile that travels on the road surface 800. The road surface 800 is an area on which an operation such as a runway or a taxiway at an airport is performed, and it is checked whether there is an abandoned object 801 such as a tool or a part. A fixture 901 is attached to the roof of the vehicle 900. The rotating lamp 902 and the laser scanner 903 are fixed to the vehicle via the fixture 901. The fixture 901 protrudes rearward of the vehicle, and the rotating lamp 902 and the laser scanner 903 are fixed. The laser scanner 903 is positioned at a height installation height Hi (for example, 150 cm) from the center ground on the center axis in the width direction of the vehicle 900. The fixture 901 includes a power cable and a communication cable (not shown) for supplying a control signal to the rotating lamp 902 and the laser scanner 903 and supplying information acquired by the laser scanner 903 to the control device. Is done.

The rotating lamp 902 includes a lamp and a rotating reflecting plate, and warns workers in the vehicle and outside the vehicle (hereinafter referred to as a user) with light.
The laser scanner 903 includes a laser light source, a receiving element, and a signal processing circuit, and determines the distance from the mounting position to the target object based on the time until the laser pulse irradiated toward the target is reflected and returned. Measure repeatedly at predetermined intervals. More specifically, the laser scanner 903 is installed so that an irradiation range having a width equal to the left and right is formed on the road surface 800 with the laser beam as the center in the vertical lower part. The laser scanner 903 changes the irradiation angle at a predetermined time interval (sampling timing), and measures the distance (sampling) at each timing. A single scan provides distance data at each sampling point from the left end to the right end. When one scan is completed, the next scan is performed. Thus, the scanning is continuously repeated while the laser scanner 903 is activated.

For example, 100 times of sampling is performed in one scan, and the scan repetition frequency is set to an arbitrary value between 25 Hz and 100 Hz. More specifically, that is, the distance to the road surface 800 (or the object surface existing on the road surface 800) is measured. Specifically, the laser beam is targeted for a road surface within a predetermined scanning width Wi (for example, 2 m from the center to the left and right, respectively) in parallel with the width direction of the vehicle 900 (that is, perpendicular to the traveling direction of the vehicle 900). ) Irradiated.
The rotating lamp 902 and the laser scanner 903 can be controlled by a user in the vehicle.

  FIG. 2 is a functional diagram of the object detection system 100. The object detection system 100 includes a control unit 110, a detection unit 120, a notification unit 130, a storage unit 140, and an input unit 150. The detection unit 120 is realized by a laser scanner 903, a control circuit of the laser scanner 903, and the like, measures a distance to an object (a road surface or an object on the road surface) at a predetermined sampling timing, and sends the measured data to the control unit 110. Supply. Specifically, the influence due to the irradiation angle is corrected, and the obtained reflection time data is converted into a distance to the road surface (if there is an object, the object). Therefore, if there is no object on the road surface in an ideal state where there is no unevenness on the road surface, the measured distance is always constant.

  The notification unit 130 includes a display unit 131, an audio output unit 132, and an illumination unit 133. The display unit 131 is realized by a display device such as a liquid crystal display or a drawing processor, and performs screen display according to a command supplied from the control unit 110. The sound output unit 132 is realized by a speaker, an amplifier, a signal processing circuit, and the like. When an object is detected, the sound output unit 132 emits sound to the driver and other users in the vehicle. For example, a buzzer sound is generated. The illumination unit 133 is realized by a rotating lamp 902. When a driving signal is supplied from the control unit 110, the lighting unit 133 turns on the lamp and rotates the reflector.

The input unit 150 is an input device such as a keyboard, a touch panel, or a mouse, and is used by the user to input commands and setting information. The input information is supplied to the control unit 110.
The storage unit 140 is an information storage device such as a RAM, a ROM, and a hard disk, and stores programs executed by the control unit 110 in addition to setting information. The setting information includes information related to a reference value necessary for detecting the presence or absence of an object based on the measured distance. The reference value can be defined as, for example, a difference (for example, 10 mm) from an assumed value (a distance to the road surface when there is no object). The reference value is not only determined for one sampling data, but may be set based on a plurality of sampling data. In short, any standard that is necessary for detecting the presence or absence of an object from the measured distance may be used. In addition, the setting information may include repetition frequency, sampling timing, and other information related to the operation of the laser scanner 903 and detection sensitivity (resolution).

  The control unit 110 is realized by a processor such as a CPU, a drawing processor, or an audio signal processor. The control unit 110 determines the presence or absence of the object 801 based on the data supplied from the detection unit 120 and the setting information read from the storage unit 140. Specifically, in the data supplied from the detection unit 120, when the difference between the distance measured at a certain sampling point and the assumed value is greater than or equal to the reference value, the control unit 110 detects that the object is at the sampling point. It is determined that it exists. If it is determined that the object 801 is present, a command to execute the notification operation is transmitted to the notification unit 130 so that the notification operation is performed using at least one of the display unit 131, the audio output unit 132, and the illumination unit 133. Output. As a result, when an object is detected, the user is notified that the object has been detected by at least one of display on the screen, notification sound, and lighting. Regardless of whether or not the object 801 is detected, the data generated by the control unit 110 is sequentially supplied to the notification unit 130, and the display unit 131 displays the distance measured sequentially.

  Control unit 110, storage unit 140, and input unit 150 are provided in vehicle 900. For example, it is installed on the console panel of the driver's seat. Further, the display unit 131, the control unit 110, the storage unit 140, and the input unit 150 may be implemented as a general-purpose PC (personal computer). In this case, a communication interface such as Ethernet (registered trademark) can be used for connection with the detection unit 120.

  FIG. 3 shows the performance of the detection unit 120 (laser scanner 903). (A) shows the resolution in the advancing direction with respect to the combination of the scanning repetition frequency and the vehicle speed at the time of detection. Here, the resolution is defined as the distance between adjacent sampling points in the traveling direction. That is, resolution is a measure of the smallest detectable object size. At a certain frequency, the resolution in the traveling direction improves as the vehicle speed decreases. Therefore, if the target is a smaller object, it is better to keep the vehicle speed during the detection operation as low as possible. On the other hand, if the vehicle speed is the same, the higher the frequency, the higher the resolution in the traveling direction, and a smaller object can be detected.

(b) is a diagram showing the relationship between the scanning repetition frequency and the sampling interval (that is, the resolution in the width direction) at a location (center and end) in the scanning region RD. Even in the case of the same frequency, the center portion has higher resolution than the end portion due to the difference in the irradiation angle. Also, if the frequency is the same place, the resolution in the width direction becomes higher as the frequency is lower.

  For example, when the vehicle travels at a speed of 10 km / h and the repetition frequency is set to 100 Hz, an object having a height not less than the reference value and a size of about 3 cm × 3 cm or more is reliably detected. Thus, the vehicle speed and frequency can be set according to the required resolution.

FIG. 4 shows an example of the operation of the object detection system 100. The user activates the object detection system 100 and starts traveling by the vehicle 900.
The detection unit 120 sequentially performs sampling and transfers the data to the control unit 110. The control unit 110 sequentially transfers the received data to the display unit 131. The display unit 131 displays the data on the screen (S500). Simultaneously with the transfer, the control unit 110 determines whether the difference between the detected distance and the reference value is greater than or equal to the reference value (S502). If it is not greater than the reference value (S502; NO), the counter is reset (S504), and the next sampling data is captured. If it is not equal to or greater than the set value, the control unit 110 increases the count number by 1 (S506) and takes in the next sampling data. Thus, a single scan (for example, a width of 4 m) is performed. For example, if the average value of the sampling interval is 4 mm, 100 sampling values can be obtained in one scan.

  When the counter value is equal to or greater than a predetermined number (S508; YES), that is, when a distance difference equal to or greater than a reference value is measured a predetermined number of times (for example, three times), the control unit 110 performs sampling. It is determined that there is some object at the position, and a notification operation command is output to the notification unit 130 (S510). Thus, the presence / absence of an object is determined based on a plurality of sampling results in order to eliminate the case where the obtained data is caused by noise or road surface unevenness. In this way, the sampling operation is repeated while the vehicle 900 is traveling, and the notification operation is executed every time an object is detected. Specifically, a predetermined message is displayed on the screen, a buzzer is sounded, and the revolving light 902 is turned on. When the user notices the notification operation, the user immediately stops the vehicle 900, goes out of the vehicle with the light, illuminates the road surface behind the vehicle 900 with the light, and searches for the detected object.

FIG. 5 is an example of a screen SC1 viewed by the user during the detection operation. (a) and (b) correspond to the results measured at different locations (time).
The screen configuration will be described using (a). A screen SC1 is displayed on the display unit 131. On the screen SC1, soft buttons SB50 to SB53 and a main screen MS are displayed. The soft buttons SB50 to SB53 are provided for the user to input information related to control and input a change command for control content. The soft button SB50 is used to input and change the setting information described above and to set and change the operation content of the notification unit 130. The soft button SB51 is for switching ON / OFF of notification by the audio output unit 132. The soft button SB52 switches on / off of the rotating lamp. The soft button SB53 is for ending the operation.

The vertical axis displayed on the main screen MS represents the difference between the installation height (assumed value) and the detected distance. That is, the zero on the vertical axis at the sampling point means that the measured value is equal to the assumed value. Note that the difference in distance at some sampling points has a negative value due to noise, road surface unevenness, and the like. The horizontal axis displayed on the main screen MS represents each sampling point in the scanning region RD. Scan data SR, which is a polygonal line obtained by connecting the plotted points of each sampling data, is drawn. The scan data SR (n) means data obtained in the n = t1th scan performed during traveling.
The effective window WX represents an interval between sampling points adjacent in the width direction. For example, if there are 100 sampling points per scan, the value is 4 mm. However, as described above, the interval between the sampling points is not the same between the central portion and the end portion of the scanning region RD due to the irradiation angle. The invalid window WY represents a reference value included in the setting information described above. That is, when the observed variation in distance is less than or equal to this reference value, it is determined that the distance is not attributable to the object.

When no object is detected, scan data SR (t1) as shown in (a) is displayed, and the screen is updated every time one scan is completed. For example, when an object is detected in the second scan of t2, a screen as shown in (b) is generated. That is, as shown in the figure, the object OB10 is displayed and a buzzer sound is emitted from the audio output unit 132.
At this time, sampling in the detection unit 120 is continuously performed. Although a finite time is required until the user stops the vehicle 900, new sampling data is supplied to the notification unit 130 one after another, and as a result, the display content of 131 is updated. During this time, the buzzer sounds. However, if the display content is updated, the user cannot grasp the position (P) of the detected object, so the reduced image of (b) is continuously displayed in a partial area of the screen SC1, and the data currently being scanned It is preferable to continue displaying with it. In this way, even if it takes time to stop the vehicle 900, the user can grasp the position in the width direction of the detected object.

In the object detection system 100, a change in distance is sequentially monitored, and a monitoring result is sequentially displayed. When detected, a notification is made by a screen, sound, rotation, and the like.
When the user confirms the notification operation, the user stops the vehicle 900, grasps the approximate position of the object (whether it is on the right / left side of the vehicle 900, or near the center) from the display content, and from the vehicle 900 Get down and do a visual search, and if you find something that you actually misplaced, collect it. At this time, even if the distance from the stop position to the measurement position is not accurately known, if the range within the scanning width spreading just behind the vehicle 900 is gradually moved from the rear end of the vehicle 900 toward the back. Eventually, the measurement position is reached. However, if the vehicle is traveling at a speed of about 5 to 10 km / h, the distance traveled from when the notification operation is confirmed until the vehicle stops can be roughly examined. Therefore, the search range can be narrowed down. As described above, according to the object detection system 100, it is possible to narrow a range to be searched visually, thereby reducing the time required for object confirmation and collection work and reducing the burden on the user.

FIG. 6 is a functional diagram of the object detection system 100A. Hereinafter, the difference from the object detection system 100 will be mainly described. The object detection system 100A includes a position acquisition unit 170. The position acquisition unit 170 is realized by a receiver that receives radio waves transmitted from a satellite such as GNSS, for example, and acquires information indicating the position of the vehicle 900 as needed. This receiver may be included in a car navigation system provided in the vehicle 900, or may be a portable terminal owned by a driver that includes a communication module for receiving location information from a base station. In short, the position acquisition unit 170 only needs to be able to measure the position of the vehicle.
In addition, the input unit 150 is configured so that the user designates an object search range (in other words, an area where work leading to object misplacement has been performed).
Control unit 110 determines the travel route of vehicle 900 such that the search by detection unit 120 covers the entire search range specified via input unit 150. Information on the determined travel route is supplied to the display unit 131.
Note that map data is stored in the storage unit 140, read as necessary, and supplied to the display unit 131. The display unit 131 can draw the position information and travel route of the vehicle 900 on the map information.

FIG. 7 is an example of the screen SC2 displayed on the display unit 131 when the search range is specified. On the screen SC2, necessary map data is read from the position acquisition unit 170 based on the position information, and the map M is displayed. The map M is a map centered on the current position of the vehicle 900. In the figure, a part of a runway RW which is a work area is displayed.
The user specifies a search range. This designation is performed, for example, by designating the four corners (A, B, C, D) of the area. Then, a rectangular region having a length L1 in a direction parallel to the runway and a length W1, A, B, C, and D in a direction parallel to the runway width is input to the control unit 110 as a search range. The Then, the control unit 110 instructs the display unit 131 to draw the search range in a color different from other ranges.

FIG. 8 is an example of the screen SC2 displayed during operation. When the user runs the vehicle 900 and starts a search, as shown in FIG. 9, the position of the vehicle 900 (current point Q) obtained based on the sequentially updated position information and the determined travel route (L) Is displayed. A region RT1 and a region RT2 in the figure represent a searched region and an unsearched region, respectively. The region RT1 and the region RT2 are drawn with different colors. As a result, the user can easily identify the progress of the work.
Note that the screen SC1 and the screen SC2 may be displayed simultaneously in different areas of one display unit, or only one of the screens is displayed at the same time, and the display target screen is switched by a user operation. Also good.

  The contents displayed to support the work by the user are not limited to those described above. For example, the current position of the vehicle 900 may be sequentially monitored, and information for supporting driving may be left for the user based on the driving route and position information. FIG. 9 shows an example of a screen displayed on the display unit 131 in the object detection system 100A having this configuration. In FIG. 9, objects OB20 and OB21 are displayed. Objects OB20 and OB21 indicate a travel line to be traveled now. The objects OB20 and OB21 are drawn based on information calculated and updated sequentially by the control unit 110 based on the travel route and position information that is sequentially updated.

  In addition, objects OB30, OB31, and OB32 are displayed on the screen SC3. The object OB30 expresses information about future driving in text information. The objects OB31 and OB21 respectively indicate the set vehicle speed and the implementation status, and are input from the setting information stored in the storage unit 140, the position information acquired by the position acquisition unit 170, and the input unit 150. Generated based on the search range. Note that the screen SC3 may be displayed simultaneously with the screen SC1 or the screen SC2, or may be switched and displayed.

The vehicle to which the object detection system according to the present invention is attached is not limited to a general-purpose vehicle such as a passenger car or a wagon car. For example, it may be a working vehicle such as a truck or other working vehicle. Moreover, the vehicle which can be remotely operated from the outside may be sufficient. In that case, the display unit 131 is provided outside the vehicle.
Further, the mounting position of the laser scanner 903 is not limited to the mode shown in FIG. For example, the fixture 901 may be provided so as to protrude forward from the roof of the vehicle 900, and the scanning region RD may be set in front of the vehicle 900. Alternatively, the scanning region RD may be set to the side of the vehicle 900. Further, the scanning direction of the laser scanner 903 need not be perpendicular to the traveling direction of the vehicle 900. For example, the laser scanner 903 may be scanned in a direction parallel to the traveling direction of the vehicle, and a predetermined two-dimensional area on the road surface 800 may be a unit of scanning.
In short, the distance sensor such as a laser scanner used in the present invention sets the travel route of the vehicle so that the search range is covered regardless of the mounting position, and repeatedly scans while traveling along the route. That's fine. In addition, the attachment position is not limited to the roof portion. For example, when the vehicle is a truck, it may be fixed to the tilt portion of the loading platform.

The above-described object determination method and control parameters are merely examples. What is necessary is just to determine the parameter and determination algorithm to be used according to a required detection accuracy (resolution) and the defined work time. For example, in order to increase the certainty of detection in the object determination, the direction parallel to the traveling direction in addition to the width direction is set to a distance in a plurality of consecutive scans (that is, not a single point in the traveling direction). It may be determined that an object is present when a predetermined change or more is detected.
In short, the object detection method of the present invention causes a sensor that measures the distance from the mounting position to the road surface in a predetermined scanning region to repeatedly scan while driving the vehicle, and the predetermined distance is measured at the distance measured by the sensor. When a change is detected, it is only necessary to notify the user of the occurrence of the change.

Also, these parameters may be correlated and automatically changed. For example, at least two of the vehicle speed, the repetition frequency, and the height reference value are linked to each other. When the vehicle speed is linked with other parameters, the object detection system 100A may be provided with a means for acquiring information related to vehicle travel from instruments mounted on the vehicle 900 or a control computer. As an example of interlocking control, in order to keep the resolution constant regardless of the vehicle speed, the current vehicle speed is acquired as needed, and the repetition frequency is increased when the vehicle speed is low, and the frequency is increased when the vehicle speed is high. It is done.
When travel information such as vehicle speed is acquired from instruments mounted on the vehicle 900 or a control computer, the travel may be further supported by displaying the acquired vehicle information on a screen.

  The illumination unit 133 may include an illumination device for supporting visual confirmation after detection and a drive mechanism for changing the orientation of the illumination device in addition to or in place of the rotation lamp 902. In this case, the control unit 110 calculates the distance from the detection position to the stop position based on the position information acquired by the position acquisition unit 170 or based on the behavior of the vehicle 900 from object detection to stop. Then, the control unit 110 calculates the detected position relationship with the position of the currently stopped vehicle 900, and preferably the detected position is the center of the range so that a predetermined range including the detected position is illuminated. In addition, the drive mechanism is controlled. Moreover, you may adjust the light quantity of the said illuminating device based on the said detection positional relationship.

  The place to which the method according to the present invention is applied is not limited to the airport, and the time to apply is not limited to night. However, in order to ensure detection accuracy, it is preferable to apply in an environment where the running surface is as flat as possible. For example, an application method is conceivable in which the object detection system 100 is attached to a forklift, a cart, or the like, the vehicle is driven in a factory, and a tool or a part that is left on the floor is searched.

DESCRIPTION OF SYMBOLS 100,100A ... Object detection system, 800 ... Road surface, 902 ... Revolving light, 903 ... Laser scanner, 900 ... Vehicle, 801 ... Object, 120 ... Detection part, 901・ ・ ・ Mounting tool, 110 ・ ・ ・ Control unit, 170 ・ ・ ・ Position acquisition unit, 150 ・ ・ ・ Input unit, 140 ・ ・ ・ Storage unit, 130 ・ ・ ・ Notification unit, 131 ・ ・ ・ Display unit, 132 ... Audio output unit, 133 ... Illumination unit, 120 ... Detection unit, 902 ... Rotating lamp, 903 ... Laser scanner

Claims (4)

A sensor mounted on the vehicle and measuring a distance from the mounting position to the road surface with a predetermined width as a scanning region;
An object detection system comprising: a notification unit that notifies a user of the occurrence of a change when a preset change is detected at a distance measured by the sensor. A measuring unit for measuring the position of the vehicle;
A designating part for designating a search range, and
The object detection system according to claim 1, wherein the notification unit identifies and displays a scanned area and an unscanned area in the search range. A determination unit for determining a travel route of the vehicle so that a scanning area by the sensor covers the entire specified search range;
The object detection system according to claim 2, wherein the notification unit displays the position of the vehicle and the determined travel route. A step of repeatedly scanning a sensor that measures the distance from the mounting position to the road surface while running the vehicle with a predetermined width as a scanning region;
And a step of notifying the user of the occurrence of the change when a preset change is detected at the distance measured by the sensor.

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