Manhole cover measurement system, manhole cover measurement method, manhole cover information analysis device, manhole cover analysis control method and program

Abstract

To provide a manhole cover measurement system, a manhole cover measurement method, a manhole cover information analyzer, a manhole cover analysis control method, and a program that can more accurately and efficiently calculate pattern height of a manhole cover.SOLUTION: A manhole cover measurement system includes: road surface measurement means that is mounted on a vehicle, irradiates a road surface where a vehicle travels with a laser beam, measures a height of the road surface at intervals corresponding to detection accuracy of a pattern height that is a difference in a height of unevenness of a pattern of a manhole cover to be detected by an optical cutting method, and outputs road surface measurement data including a height of each point on the road surface and reflection intensity of the laser beam; region extraction means that extracts a manhole cover region, using the reflection intensity of the laser beam; and pattern height calculation means that calculates the pattern height of the manhole cover from the difference in height in the extracted manhole cover region.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a manhole cover measurement system for measuring manhole covers on the road, a manhole cover measurement method, a manhole cover information analysis device, a manhole cover analysis control method, and a program. [Background technology]

[0002] Manholes that serve as access points to sewers and the like are located on the road surface. Usually, manholes are covered with manhole covers. As road and sewerage facilities are developed, the number of manholes is also increasing, and the effort required to manage manhole covers is increasing. Patent Document 1 discloses a technology that stores surface image information of multiple types of manhole covers in advance, detects images of manhole covers from photographed data of the road surface taken by a camera mounted on a vehicle, compares the detected images of the manhole covers with the surface image information to identify the type, and stores and manages the type in association with information on the detected position. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2015-191573 A Summary of the Invention [Problem to be solved by the invention]

[0004] The surface of a manhole cover has a pattern made up of projections and recesses. These projections and recesses are worn away by vehicle traffic, etc. Managing manhole covers includes managing the difference in height between the projections and recesses on the surface of the manhole cover (pattern height). However, with conventional technology, checking the pattern height required visual confirmation of an image of the manhole cover, which was inefficient. It is also possible to calculate the pattern height from an image of the manhole cover, but the shadows on the image caused by the pattern are affected by factors such as sunlight and the slope of the road surface, making it difficult to accurately calculate the pattern height.

[0005] An object of the present invention is to provide a manhole cover measurement system, a manhole cover measurement method, a manhole cover information analysis device, a manhole cover analysis control method, and a program that can calculate the pattern height of a manhole cover more accurately and efficiently. [Means for solving the problem]

[0006] In order to achieve the above object, the present disclosure provides: It is installed in a vehicle and is used for the road surface on which the vehicle runs. Repeated curtain pattern A laser beam is irradiated to the road surface at intervals according to the detection accuracy of the pattern height, which is the difference in height of the unevenness of the pattern of the manhole cover to be detected by the light cutting method. Regarding the measurement along the side line for each irradiation of the laser light a road surface measuring means for measuring a height and outputting road surface measurement data including the height of each point on the road surface and the reflection intensity of the laser light; an area extraction means for extracting a manhole cover area using the reflection intensity; a pattern height calculation means for calculating the pattern height of the manhole cover based on the height difference within the extracted manhole cover area; Equipped with 、 The pattern height calculation means defines local regions along each of the plurality of measurement side lines within the manhole cover region, and calculates the difference between the maximum value and the minimum value of the height in the local region as the pattern height. This is a manhole cover measurement system characterized by the above. Effect of the Invention

[0007] According to the present disclosure, it is possible to more accurately and efficiently calculate the pattern height of a manhole cover. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a diagram illustrating road surface measurement in the manhole cover measurement system of this embodiment. [Diagram 2] 1 shows an overall configuration diagram of a manhole cover measurement system according to the present embodiment. [Diagram 3] FIG. 4 is a diagram illustrating measurement timing of each measurement unit. [Figure 4]FIG. 2 is a diagram illustrating measurement of road surface height. [Diagram 5] FIG. 2 is a diagram illustrating a cross section of a manhole. [Figure 6] 13 is a flowchart showing a control procedure of a manhole cover analysis control process. [Figure 7] 13 is a flowchart showing a control procedure of an absolute position specifying process. [Figure 8] FIG. 13 is a diagram showing an example of a display screen of a manhole cover analysis diagram. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram for explaining road surface measurement in a manhole cover measurement system 1 of this embodiment.

[0010] The manhole cover measurement system 1 includes a measurement device 100 for measuring the road surface (road surface) of the road and the position and posture of the vehicle W. The measurement device 100 is mounted on the roof of the vehicle W or the like to perform measurement operations, and can measure the road surface (including the surface of the manhole cover) vertically downward from the rear side of the traveling vehicle W. The measurement device 100 is also fixed to the vehicle W, and measures the position and posture that change due to the traveling of the vehicle W, changes in direction, tilt, up and down movement, and other movements.

[0011] The vehicle W may be a general vehicle type as long as it is possible to mount and fix the measurement device 100 thereon, and does not have to be a vehicle dedicated to measurement. The measurement device 100 may be provided with a member for mounting and fixing the measurement device 100 to the roof of the vehicle W.

[0012] FIG. 2 shows an overall configuration diagram of the manhole cover measurement system 1 of this embodiment. The manhole cover measurement system 1 includes the above-mentioned measurement device 100 and a processing device 200 that processes measurement data as the manhole cover information analysis device of this embodiment.

[0013] The measurement device 100 includes a road surface measurement unit 110 (road surface measurement means), a vehicle measurement unit 120 (vehicle measurement means), a surroundings measurement unit 130, a synchronization signal output unit 140, a control unit 150, a memory unit 160, and a communication unit 170. Of these, the road surface measurement unit 110, the vehicle measurement unit 120, and the surroundings measurement unit 130 (collectively referred to as each measurement unit) perform measurements related to the manhole cover. Regardless of the form shown in Fig. 1 above, the control unit 150, the memory unit 160, and the communication unit 170 of the measurement device 100 may be located inside the vehicle W and communicatively connected to each measurement unit.

[0014] The road surface measurement unit 110 includes an illumination unit 111, an image capture unit 112, a timing unit 113, etc., and measures the height of the road surface and outputs the resulting road surface measurement data. The irradiation unit 111 has a light emitting unit 1111 and a scanning unit 1112. The light emitting unit 1111 generates and emits laser light (for example, visible light to near infrared light). The scanning unit 1112 scans the laser light emitted from the light emitting unit 1111 to output light in a curtain-like range spreading in the scanning direction. The scanning range may be the entire width or a range equivalent thereto in the width direction (transverse direction, i.e., a direction perpendicular to both the vertical direction and the traveling direction of the vehicle W) of the road (lane) to be measured when the vehicle W is traveling along the road (lane). The detection interval is determined to an interval according to the detection accuracy. The position interval of the measurement along the width direction (scanning direction) needs to be equal to or less than the lower limit (for example, 5 mm) of the width (pattern width) of the recessed and protruding parts on the surface of the manhole cover to be detected, and is, for example, 1 mm. Furthermore, the position interval of the measurements in the traveling direction of the vehicle W (the direction in which the road extends) is determined by a combination of the photographing interval of the photographing unit 112 and the traveling speed of the vehicle W. This position interval may also be determined to be equal to or smaller than the lower limit of the pattern width of the manhole cover.

[0015] The photographing unit 112 performs a photographing operation to detect reflected light of the laser light emitted by the irradiation unit 111 from the road surface. The photographing unit 112 is located at a place where it can detect and photograph reflected light obliquely with respect to the incident direction (vertical downward direction) of the laser light to the road surface in order to specify the reflection position, i.e., the height of the road surface (road surface height), by the light section method. That is, the irradiation unit 111 and the photographing unit 112 are fixed on the vehicle W on which the measurement device 100 is mounted. The photographing conditions, such as the focal position, optical axis direction, viewing angle, and lens distortion of the photographing unit 112, and the emission position and emission angle of the irradiation unit 111, are stored in a storage unit (not shown), and a control unit (not shown) calculates a relative reflection position (road surface position) with respect to the emission position of the light in a coordinate system fixed to the vehicle W from the position of the pixel where the reflected light is detected in the photographing unit 112 and the photographing conditions. The measurement result of the reflection position may be obtained as a distance from the emission position of the light. By this light-section method, the photographing unit 112 acquires the height of the reflection position on each scanning line, that is, the road surface height and the distribution of reflection intensity, as road surface measurement data. The accuracy of identifying the road surface height needs to be equal to or lower than the lower detection limit of the manhole cover to be detected, and for example, the resolution and installation conditions of the measuring device 100 are such that it can measure at intervals of 0.5 mm. At each date and time when the measurement is performed, the positions of the irradiating unit 111 and the photographing unit 112 change according to the travel of the vehicle W, and therefore the absolute position (geographical position in a coordinate system fixed to the Earth's surface) of the acquired road surface measurement data changes.

[0016] Since this light-section method uses laser light for measurement, it is less affected by shadows compared to measurements using normal photography that does not use laser light, and it is easier to measure the height (pattern height) and shape of the convex parts relative to the concave parts on the surface of the manhole cover with higher accuracy than before. In addition, since the measurement is not subject to the restrictions of time, season, or weather, it is less likely that there will be limitations on the measurement period or postponements to the measurement schedule.

[0017] The clock unit 113 measures time and outputs the current date and time. The clock unit 113, for example, counts a predetermined frequency signal generated by the oscillation of an oscillator to specify the date and time. The oscillator is, for example, a quartz oscillator or a MEMS oscillator. The oscillator having this oscillator may be temperature compensated for the oscillation frequency, or may be equipped with a thermostatic bath. However, the date and time output by the clock unit 113 may deviate from the correct date and time over time. For example, when an image capture signal is input from the image capture unit 112 at the image capture timing, the clock unit 113 outputs the date and time of this timing as the image capture date and time. The image capture date and time is associated with the measurement result of the road surface measurement unit 110 based on the image capture result at the image capture date and time, and is included in the road surface measurement data. In addition, when a synchronization signal is input from the synchronization signal output unit 140, the clock unit 113 outputs the date and time of the timing when the synchronization signal is input as the synchronization date and time. The synchronization date and time is included in the road surface measurement data without being associated with the measurement result.

[0018] The vehicle measurement unit 120 includes a satellite positioning unit 121, an attitude measurement unit 122, a timer unit 123, etc., and performs measurements related to the vehicle (reference position) and outputs the measurements as vehicle measurement data. The measurements related to the vehicle are performed for at least a period corresponding to the measurement of the height of the road surface by the road surface measurement unit 110. The vehicle measurement data includes absolute position data of the vehicle obtained by the satellite positioning unit 121 and attitude data of the vehicle obtained by the attitude measurement unit 122.

[0019] The satellite positioning unit 121 performs a positioning operation to measure the current absolute position of the vehicle W (i.e., the reference position of the vehicle W on which the measuring device 100 is mounted) by receiving radio waves from multiple (at least four) positioning satellites related to the GNSS (Global Navigation Satellite System), and outputs absolute position data. The satellite positioning unit 121 may include, for example, a satellite related to the GPS (Global Positioning System), which is a satellite positioning system of the United States, as a positioning satellite capable of receiving and decoding radio waves, but may not be limited to this. For example, the positioning satellites to be received may include a satellite related to the GLONASS (Globalnaya Navigatsionnaya Sputnikovaya Sistema / Global Navigation Satellite System), which is a satellite positioning system of Russia, and these may be used in combination. In addition, transmission radio waves of multiple frequency bands in each satellite positioning system may be used in combination. The absolute position is represented by, for example, three components, namely, latitude, longitude, and altitude. In addition, the current date and time are acquired together with the absolute position.

[0020] The attitude measurement unit 122 includes an acceleration sensor 1221 and a gyro sensor 1222, measures the attitude of the vehicle W on which the measurement device 100 is mounted, and outputs attitude data. The acceleration sensor 1221 and the gyro sensor 1222 can each measure acceleration and rotation speed in three orthogonal axial directions (six axes including the three axes and the rotation axis). The attitude of the vehicle determined by sequentially adding up each of these and adding up the initial attitude may include the vehicle's direction (rotation in a plane parallel to the road surface), inclination (rotation in a plane including a direction perpendicular to the road), up-down movement (vibration), and acceleration / deceleration (change in translation speed).

[0021] The clock unit 123, like the clock unit 113, clocks and outputs the current date and time. Here, the clock unit 123 corrects the date and time it clocks based on the date and time specified by the satellite positioning unit 121 as needed. That is, the date and time output by the clock unit 123 is accurate to the level required by the manhole cover measurement system 1 of this embodiment. When the measurement signals are input from the satellite positioning unit 121 and the attitude measurement unit 122 at the measurement timing, the clock unit 123 outputs the date and time of those timings as the positioning date and time and the measurement date and time, respectively. The positioning date and time are associated with the absolute position measured at the positioning date and time and included in the absolute position data, and the measurement date and time are associated with the attitude measured at the measurement date and time and included in the attitude data. When the synchronization signal is input from the synchronization signal output unit 140, the clock unit 123 outputs the date and time of that timing as the synchronization date and time. The synchronization date and time is included in the vehicle measurement data without being associated with either the absolute position or the attitude.

[0022] The surrounding measurement unit 130 has a laser scanner 131. The laser scanner 131 sequentially emits laser light in all directions around the vehicle, detects the reflected light, measures the distance to the reflective surface around the vehicle by TOF (Time of Flight) from the elapsed time until detection and the speed of light, and outputs surrounding measurement data. The reflective surface around the vehicle includes the road surface outside the measurement range of the road surface measurement unit 110, and preferably further includes surrounding road facilities, buildings, plants, and the ground surface. By integrating the continuous measurement results by the surrounding measurement unit 130, three-dimensional road data including the shape of the road surface around the measurement range by the road surface measurement unit 110 is generated. The resolution of the surrounding measurement data may be lower than the resolution of the road surface measurement data, and it is not necessary to accurately detect the unevenness of the manhole cover from the surrounding measurement data.

[0023] The measurement result of the surrounding measurement unit 130 is relative based on the position of the measurement device 100 of the vehicle W. Although not particularly limited, the vehicle measurement unit 120 and the surrounding measurement unit 130 may be located together in the same housing. Here, the surrounding measurement unit 130 shares the date and time counted by the timing unit 123 with the vehicle measurement unit 120. When a measurement signal is input from the surrounding measurement unit 130 at the measurement timing by the laser scanner 131, the timing unit 123 outputs the date and time at that measurement timing as the measurement date and time. The measurement date and time is associated with the result of the surrounding measurement at that measurement date and time and is included in the surrounding measurement data.

[0024] The synchronization signal output unit 140 outputs the above-mentioned synchronization signal to the road surface measurement unit 110, the vehicle measurement unit 120, and the surroundings measurement unit 130. The synchronization signal output unit 140 is realized, for example, by an MCU (Micro Control Unit), and outputs a synchronization signal every time it moves a predetermined distance, for example, 3 m, based on its own movement amount acquired from a rangefinder (not shown). For example, when the vehicle W is traveling at a constant speed of 60 km / h, the time interval of the synchronization signal is 180 msec. Alternatively, the synchronization signal output unit 140 may have an oscillation circuit and output a synchronization signal every time a predetermined time has elapsed.

[0025] The control unit 150 has a CPU (Central Processing Unit) and the like, and acquires measurement data and synchronization date and time data from each measurement unit, and stores them in the storage unit 160. The control unit 150 also controls the transmission output of the communication unit 170 for the data stored in the storage unit 160.

[0026] The storage unit 160 stores the measurement data from each measurement unit. The storage unit 160 has a non-volatile memory. The non-volatile memory may be, for example, a flash memory and / or a hard disk drive (HDD).

[0027] The communication unit 170 communicates with the outside via a network such as the Internet or a LAN (Local Area Network). The outside includes the processing device 200. Measurement data from each measurement unit of the measurement device 100 is transmitted to the processing device 200 for processing. The communication unit 170 does not need to be able to communicate with the outside at all times during the measurement operation by the measurement device 100. The communication unit 170 may be connected to the network after the measurement is completed.

[0028] The processing device 200 includes a control unit 210, a storage unit 220 (storage means), a communication unit 230, and an input / output unit 240. The processing device 200 may be, for example, a normal PC, and may be separate from the measuring device 100.

[0029] The control unit 210 is equipped with a CPU (Central Processing Unit) and executes calculation processing, and serves as the area extraction means, pattern height calculation means, display control means, and position identification means of this embodiment, performing analysis processing of the measurement data received from the measuring device 100 and generation processing of a display image. The analysis processing includes extraction of the measurement points of the manhole cover, fitting to the shape of the manhole cover, calculation of the pattern height of the manhole cover, and identification of the geographical three-dimensional position of the manhole cover, as described below.

[0030] The storage unit 220 stores the measurement data (road surface measurement data, vehicle measurement data, and surrounding measurement data) received from the measuring device 100, analysis data of these measurement data by the control unit 210 (including manhole cover data and three-dimensional road data 221 described later), and a program 222 for processing related to the analysis process. The storage unit 220 has, for example, a volatile memory (RAM: Random Access Memory) and a non-volatile memory. The non-volatile memory may include a HDD (Hard Disk Drive). The volatile memory provides a working memory space for the CPU of the control unit 210. The manhole cover measurement system 1 may include a database device or the like other than the memory unit 220 outside the processing device 200. Alternatively, an HDD or the like may be attached directly and externally to the measuring device 100, and the measurement data may be written to this HDD in real time. After the measurement is completed, the HDD may be removed from the measuring device 100, carried, and attached to the processing device 200 to operate as the memory unit 220.

[0031] The communication unit 230 communicates with the outside via a network such as the Internet or a LAN. The outside includes the measuring device 100, and measurement data in the measuring device 100 can be acquired at any time or collectively after the measurement is completed. Note that the measuring device 100 and the processing device 200 are not directly connected to each other via a network, and data may be exchanged indirectly via a data server or the like.

[0032] The input / output unit 240 includes an output unit that shows the analysis results to the user, such as a display unit 241 having a display screen or a printer that forms images, and an input unit such as an operation reception unit 242 that receives requests for content to be output, etc. The analysis data acquired by the processing of the control unit 210 is output by the output unit with the content and display form specified by the input unit.

[0033] Next, the measurement operation by the measurement device 100 of the manhole cover measurement system 1 of this embodiment will be described.

[0034] FIG. 3 is a diagram for explaining the measurement timing of each measurement unit. FIG. 3(a) shows a list of the operations of each measurement unit.

[0035] The road surface measurement unit 110 determines the initial measurement timing based on the synchronization signal, and thereafter repeats the operation of measuring the road surface at equal time intervals a, for example, 0.12 msec intervals, during a movement of 3 m (road surface measurement step). When the vehicle W is traveling at a constant speed of 60 km / h, 1500 measurements are taken at 2 mm distance intervals between two synchronization signals at 3 m intervals, i.e., during a period of 180 msec. As described above, the measurement results output by the road surface measurement unit 110 at each measurement timing are marked with the date and time t1 of the clock unit 113. The road surface measurement unit 110 also outputs the synchronization date and time t1 (Tk) indicating the timing at which the synchronization signal Tk (k=0, 1, 2...) was input.

[0036] The satellite positioning unit 121 performs a positioning operation at a fixed time interval b, for example, at 50 msec intervals, independent of the synchronization signal, and outputs the result as absolute position data of the vehicle W. That is, the positioning operation is performed approximately 3.6 times during the above-mentioned 180 msec. The absolute position data is each assigned the date and time t2 of the clock unit 123, that is, the date and time specified and adjusted in the positioning operation. As described above, this date and time t2 is accurate. The data output from the satellite positioning unit 121 also includes the synchronization date and time t2 (Tk) at the timing when the synchronization signal Tk is input.

[0037] The attitude measurement unit 122 acquires the measurement results of the acceleration sensor 1221 and the gyro sensor 1222 at a constant time interval c, for example, at 5 msec intervals, independent of the synchronization signal, and outputs them as attitude data of the vehicle W. The attitude data is each assigned a date and time t3 (here, equal to t2) counted by the timer unit 123. The attitude data is acquired 36 times during the above-mentioned 180 msec. The positioning operation by the satellite positioning unit 121 and the measurement operation by the attitude measurement unit 122 constitute the vehicle measurement step in the manhole cover measurement method of the present invention.

[0038] The laser scanner 131 of the surroundings measurement unit 130 measures the positions of surrounding objects including the road surface (surrounding road surface) outside the measurement range of the road surface measurement unit 110 at a constant time interval d, for example, 5 msec, independent of the synchronization signal Tk, and outputs each of the positions as surroundings measurement data. The surroundings measurement data is accompanied by the date and time t4 (here, equal to t2) of the timing unit 123 at the timing of measuring the surroundings.

[0039] FIG. 3B is a diagram for explaining synchronization of measurement data by each measurement unit. As described above, the synchronization signal output unit 140 outputs the synchronization signal Tk every 3 m of movement and inputs it to the road surface measurement unit 110, the vehicle measurement unit 120, and the surroundings measurement unit 130. The road surface measurement unit 110 and the vehicle measurement unit 120 acquire the synchronization dates and times t1(Tk) and t2(Tk), which are counted at the timing when the synchronization signal Tk is input.

[0040] A conversion function from date and time t1 to date and time t2 is calculated by polynomial approximation of the relationship between these synchronization dates and times. The amount of deviation between date and time t1 and date and time t2 can change over time. For this reason, it is preferable to use a function of the date and time as the conversion function. For example, the deviation g(t1) between date and time t1 and date and time t2 can be expressed as a quadratic polynomial g(t1) = t1 - t2 = A t1 2 +B·t1+C, and define a conversion function f(t1)=t1-g(t1) that subtracts the deviation g(t1) from date and time t1, and use regression analysis to calculate the constants A, B, and C that approximately hold {t1(Tk), t1(Tk)-t2(Tk)}=[{t1(T0), t1(T0)-t2(T0)}, {t1(T1), t1(T1)-t2(T1)}, …]. If g(t1)=t2-t1 is defined, then f(t1)=t1+g(t1). For example, the conversion function f(t2) that directly converts date and time t1 to date and time t2 can be calculated using the quadratic polynomial t2=D·t1 2+E·t1+F, and the constants D, E, and F that approximately hold true for (t1,t2)=[{t1(T0),t2(T0)},{t1(T1),t2(T1)},…] can also be calculated by regression analysis. Note that the quadratic polynomial is just one example, and the conversion function may be a linear function or a cubic or higher degree function. The conversion function may be calculated for each interval obtained by dividing the measurement data into a predetermined time period (for example, one hour) and used for each interval. This is useful when the temperature changes significantly during measurement. The timing of all road surface measurements based on the accurate date and time t2 based on satellite positioning is identified by substituting the measurement date and time attached to the road surface measurement data of the road surface measurement unit 110 into the calculated conversion function. If dates and times t3 and t4 are different from date and time t2, the conversion function from date and time t3 to date and time t2 and the conversion function from date and time t4 to date and time t2 are calculated in the same procedure for these dates and times, and the measurement timing based on date and time t2 is identified for both.

[0041] In the manhole cover measurement system 1, since no other measurements are taken at the same time as the road surface measurement at date and time t1, the absolute position and vehicle attitude at the road surface measurement at date and time t1 are calculated by interpolation (for example, linear interpolation) using data before and after date and time t1. For example, the absolute position at date and time t1(3) is calculated as an internal division point of the absolute positions at dates and times t2(0) and t2(1), and the vehicle attitude at date and time t1(3) is calculated as an internal division point of the attitude at dates and times t3(0) and t3(1). Alternatively, the absolute position and attitude may be calculated by interpolation using measurement data at three or more dates and times before and after the road surface measurement.

[0042] For measurements taken at regular intervals, it is not necessary to provide measurement date and time data for all measurement data. All measurement dates and times can be specified by the date and time of synchronization, the time lag from the synchronization to the first measurement thereafter (aL, bL, cL, dL in FIG. 3(b)), and the measurement time intervals a, b, c, d. The process of identifying the exact date and time of the measurement timing as described above is not particularly limited, but may be performed by the processing device 200 that acquires the measurement data from the measuring device 100. In other words, the control unit 210 also operates as a road surface measurement data acquisition means that acquires road surface measurement data by utilizing the communication between the communication unit 170 of the measuring device 100 and the communication unit 230 of the processing device 200.

[0043] Next, the manhole cover extraction operation performed by the control unit 210 of the processing device 200 as manhole cover extraction means and the operation of calculating the pattern height of the manhole cover performed as pattern height calculation means will be described. FIG. 4 is a diagram for explaining measurement of road surface height. As shown in Fig. 4(a), the reference position P(t2(i)) of the vehicle W at each positioning date and time is acquired. Here, each reference position for i = 0 to 2 is shown. The reference position P may be the position of the satellite positioning unit 121, that is, the result of the satellite positioning may be used as it is.

[0044] Next, the date and time t1(j) when the road surface was measured is converted to date and time t2 to identify date and time t2(t1(j)) (j = 0, 1, 2 ...), and the reference position P(t2(t1(j)) of the vehicle W at this date and time is identified by linear interpolation of the reference positions before and after that date and time. In addition, the attitude of the vehicle W at this date and time t2(t1(j)) is determined by linear interpolation of the attitudes of the vehicle W before and after that date and time in the vehicle measurement data, etc.

[0045] As shown in Fig. 4(b), measurement lines L(j) indicating the reference range for road surface measurement at each measurement timing are determined by considering the relative relationship between the reference position P of the vehicle W and the measurement position on the road surface, as well as the posture of the vehicle W. If the vehicle W is traveling straight on a flat road at a constant speed, the measurement lines L will be equally spaced and parallel to each other, but if the vehicle W changes its direction of travel or accelerates or decelerates, some of the measurement lines L will become non-parallel or will be unevenly spaced.

[0046] The measurement results of each measurement line L by the road surface measurement unit 110 at the timing of each measurement line L indicate the relative deviation in the height direction with respect to the measurement line L. That is, as shown in FIG. 4(c), the height H(j) of the road surface on the measurement line L is specified based on each measurement line L. This allows data on the height of the road surface to be obtained for each absolute horizontal position (latitude, longitude) on the road to be measured. If the vehicle height is specified in advance, the measurement line L will be on the same plane as the original road surface height on a flat road that does not have depressions, cracks, manhole covers, etc. Therefore, the difference between the determined road surface height H(j) and the height (road surface height) of the measurement line L is the amount of unevenness from the original road surface.

[0047] In the manhole cover measurement system 1, manhole covers are extracted from the road surface measurement data obtained in this manner, and the amount of unevenness (pattern height) of the extracted manhole cover is calculated to identify the degree of wear.

[0048] 5 is a diagram illustrating a cross section of a manhole U. Here, for the sake of explanation, two recesses are shown on the manhole cover C, but in reality, there may be many recesses that are small compared to the size of the manhole cover C. These many recesses are recesses for each local area on the manhole cover C, and may be connected on a horizontal cross section. As shown in FIG. 5(a), a manhole U extends downward (downward in the Z direction) from a pavement surface Ra on a road R, and a manhole cover C is located at the boundary with the pavement surface Ra.

[0049] The manhole cover C may be made of cast iron, for example, and may include a colored portion on the surface, such as a colored resin coating on the recessed portion. These are made of a different material from the paved road R (asphalt or concrete), and the characteristics of the reflection intensity of the visible light and near-infrared laser light are different from the paved surface Ra. The manhole cover C also has a pattern made of unevenness. The pattern here includes all patterns expressed by unevenness, such as letters, signs, figures, pictures, and designs. The pattern height d, which is the difference in height between the top surface CT and the bottom surface CB of the pattern, gradually becomes smaller as the top surface CT is worn away by the passage of vehicles, etc. The way in which the pattern height d becomes smaller may vary depending on the position of the manhole cover C relative to the paved surface Ra, the shape and size of the pattern on the manhole cover C, and the like. The pattern height d that has become smaller due to wear may not be uniform within the manhole cover C, but may vary depending on the location. The manhole cover C is also installed in a frame made of the same material as the manhole cover C.

[0050] In the process of extracting a manhole cover area from road surface measurement data, as described above, measurement points whose reflection intensity has the reflection characteristics of a manhole cover C are extracted as measurement points of the manhole cover C. For example, a lower limit value for the reflection intensity of asphalt is determined in advance, and measurement points whose reflection intensity is lower than this lower limit value are extracted. Furthermore, for example, in order to detect manhole covers C made of other materials as well, a lower limit value for the reflection intensity of the white line and an upper limit value for the reflection intensity of concrete are determined in advance, and measurement points whose reflection intensity is lower than this lower limit value and higher than this upper limit value are extracted.

[0051] Next, the portions where these measurement points are distributed together are grouped. For example, morphological transformation is used for grouping. In an orthogonal projection image in which the road surface is viewed from above parallel to the road surface or from above vertically, the range of pixels that are the measurement points of the manhole is expanded by a predetermined degree, and then the expanded area is contracted by the above degree, thereby connecting the gaps of the measurement points of the manhole cover C defined by this degree. If the size of the pixels differs between the extension direction of the road (driving direction) and the intersecting direction perpendicular thereto (road width direction), the predetermined degree may be different for each. The grouped areas are regarded as candidate areas for the manhole cover C.

[0052] Furthermore, when extracting the manhole cover area based on reflection intensity, there are cases where the measurement points in the colored part are not extracted. Even in such cases, it is expected that the candidate area for the manhole cover C will have a closed area formed by the convex part of the edge. Therefore, a correction is made to include the measurement points in the detected closed area that are not considered to be in the manhole cover area in the candidate area for the manhole cover. This makes it possible to extract the area of ​​the manhole cover C that includes the colored part, including the pattern.

[0053] The size of the candidate area for the manhole cover is estimated. For example, the average value of the two-dimensional positions (X, Y coordinates) of the measurement points in the candidate area viewed from above is determined as the center position, and a circle or ellipse that best fits the outer edge of the candidate area with respect to the center position is determined. If the radius of the circle (ellipse) area is a plausible size for a manhole cover, for example, within a range of 300 to 1200 mm, the candidate area is confirmed as a manhole cover area. Since the size of the manhole cover is standardized into a plurality of types, the confirmed manhole cover area is identified as a manhole cover with a standard size that best matches the radius of the obtained circle (ellipse). In addition, whether or not the deviation rate of the outer edge of the candidate area from the determined circular area is within a predetermined standard range may be added to the conditions for confirming the area as a manhole cover area. The outer edge may be identified, for example, by whether or not adjacent pixels corresponding to the measurement points include pixels outside the candidate area. In the case of fitting with an ellipse, the condition for confirming the area as a manhole cover area may also be added that the deviation amount of the ellipticity from 1 is within a standard range. Instead of fitting, various known image recognition methods such as pattern matching and Hough transform can also be used.

[0054] Next, the effect of the inclination in the extracted manhole cover area is removed. As shown in FIG. 5(b), when the pavement surface Ra and the manhole cover C are inclined, the position h in the height direction (Z direction) of each point of the entire road surface without considering unevenness can be obtained as the average value (moving average value) of the height h in a range of a predetermined size (here, shown by width w in the extension direction of the road (Xa direction)) centered on the point. For example, the range for obtaining the moving average can be a rectangle with one side of w, a circle with a diameter of w, or a line segment with a width of w. If the predetermined size is equal to or smaller than the pattern width, the pattern height itself will be averaged, so a range larger than the pattern width is determined.

[0055] Also, the inclination direction Xa (mainly along the extension direction of the road) in the manhole cover area may be identified, and a predetermined range in which the length in the direction perpendicular to the length of the inclination direction (Y direction) is relatively long may be determined. Since the vehicle W mainly travels in the inclination direction Xa, the Y direction tends to be nearly parallel to the measurement line L. Therefore, a moving average may be calculated for each of a predetermined number of measurement lines L. The range in which the moving average is calculated is determined within the manhole cover area.

[0056] The effect of the inclination of the manhole cover area is removed by subtracting the height h calculated for each point from the height measured at each point in the manhole cover area. At that time, by calculating the height h from the height within the manhole cover area, the effect of the inclination of the manhole cover C can be appropriately removed without being affected by ruts or cracks in the pavement surface Ra. Instead of the moving average, a low-pass filter (LPF) or the like may be applied to obtain a value that reflects the overall change trend as the original road surface height, and this value may then be subtracted from the height of each point. Also, wavelet analysis may be used to remove changes according to spatial frequencies other than those due to unevenness caused by patterns.

[0057] Next, a correction is made to remove the frame area that may be included in the manhole cover area. Specifically, the area is corrected to match the standard size of the manhole cover C to be extracted. In this case, for example, a manhole cover area extracted as a manhole cover with a diameter of 650 mm is corrected to a circular area with a diameter of 650 mm having the above-mentioned center position. Alternatively, the area is corrected to a size obtained by multiplying the size of the extracted area by a certain percentage. In this case, for example, in a manhole cover area extracted as a circular manhole cover, 10% of the diameter is determined to be the frame, and the center position of the extracted manhole cover area is fixed and the area is corrected to a circular area with a diameter of 90% of the maximum width of the manhole cover area. By removing the frame, the error of calculating the depth of the groove between the frame and manhole cover C as the pattern height can be prevented.

[0058] Then, the pattern height within the manhole cover area is calculated. As shown in Fig. 5(a), the upper surface of the manhole cover C is roughly divided into either a top surface CT or a bottom surface CB depending on the pattern. When the measurement points in the manhole cover area located on the measurement line L by the road surface measurement unit 110 are traced in order from one end to the other end, the height changes repeatedly, dropping sharply from the height of the top surface CT to the height of the bottom surface CB, and then returning to the height of the top surface CT again. One period of this fluctuation, for example, each section from the position where the height drop begins (the drop start point) to the next drop start point, is divided into one-dimensional local areas b (the edge of the manhole cover C is also considered to be the boundary of the local area), and the difference between the maximum and minimum values ​​of the height in each local area b, i.e., the height difference, is calculated as the pattern height d. Note that instead of the drop start point, the position where the increase in height ends (ascent end point), the position where the increase in height begins (ascent start point), or the position where the decrease in height ends (decrease end point) may be focused on, and in each case, the section from the ascent end point to the next ascent end point, the section from the ascent start point to the next ascent start point, and the section from the decrease end point to the next decrease end point may be divided as the local region b. Also, the scanning line is not limited to the measurement line L, i.e., a line parallel to the Y axis in the figure, but may be a line in one direction parallel to the horizontal plane, such as a line parallel to the X axis or a line at 45 degrees to the X axis and the Y axis.

[0059] Once the pattern height d is found for each local region b, the minimum value dmin of the pattern heights d in all local regions b is detected for each manhole cover region. As described above, the pattern height d is not constant even within a manhole cover region due to wear, so this minimum value dmin is identified as the pattern height da representative of the manhole cover C being measured. By selecting the minimum value dmin, it is possible to eliminate the mistake of identifying an air vent hole formed in the manhole cover C as the pattern height da. The identified pattern height da is stored in association with the manhole cover C using an identification code, position information, etc., along with the measurement date and time.

[0060] The measurement date and time is not particularly limited, and may be, for example, the measurement date and time of the earliest measurement among the measurement points in the manhole cover C. Alternatively, the start date and time of the road surface measurement including multiple manhole covers C may be collectively assigned to the multiple manhole covers C. The measurement date and time may be only the year, month, and day without including the time (hour, minute, second). Also, the operation receiving unit 242 may set the measurement date and time by receiving an input operation from the user or the like.

[0061] When a manhole cover C that has not been stored is newly measured, a new identification code and position information are set for the manhole cover C. The position information is a three-dimensional geographical position that can specify an absolute position, such as latitude, longitude, and height (altitude). The three-dimensional geographical position may be, for example, a representative position of the manhole cover C, or may be the center position when the manhole cover area is circularly fitted as described above. The three-dimensional geographical position may also include the radius of the circle obtained by the fitting. Alternatively, in addition to the representative position, the maximum and minimum latitudes, maximum and minimum longitudes, and maximum and minimum altitudes of the extracted manhole cover C may each be specified and set as position information.

[0062] When a new pattern height da is obtained for a manhole cover C that has already been stored, it is stored as additional data associated with that manhole cover C.

[0063] Whether or not a manhole cover that has already been stored is the same as the manhole cover C with the specified pattern height da is determined based on the above position information. For example, if four coordinates, the highest latitude, the lowest latitude, the highest longitude, and the lowest longitude, are stored, the absolute values ​​of the differences between the four coordinates of the stored manhole cover and the four coordinates of the manhole cover C with the specified pattern height da may be calculated and added, and whether or not the sum is equal to or greater than a predetermined reference value may be determined.

[0064] When the specification of the pattern height da and the storage of the data associated with the manhole cover C are completed, the measurement results and calculation results are displayed together on the display unit 241. For example, the display unit 241 displays a point cloud of the target manhole cover C and the three-dimensional geographical positions of the surrounding area measured by the road surface measurement unit 110. Points indicating the height of each measurement point of the target manhole cover C may be highlighted with a color or size different from the points outside the manhole cover C. For the manhole cover C included in this display, the identification information of the manhole cover C, the specified pattern height da, and the measurement date and time are displayed by a speech bubble or in a separate window.

[0065] In addition, this display may indicate whether or not the manhole cover C needs to be replaced depending on the result of comparing the specified pattern height da with a predetermined reference height. In other words, if the pattern height da is less than the reference height, a display is made indicating that the manhole cover C needs to be replaced.

[0066] Furthermore, not only the measurement results by the road surface measurement unit 110 but also each measurement point included in the three-dimensional road data 221 including the surrounding road surface measured by the surrounding measurement unit 130 may be displayed. Alternatively, the display of the measurement points by the road surface measurement unit 110 may be limited to only the manhole cover C, and the manhole cover C and the three-dimensional road data 221 may be displayed superimposed on each other to reduce the drawing process. This makes it easier to grasp the positional relationship of the manhole cover C analyzed from the surrounding situation. In this case, the measurement points of the three-dimensional road data 221 and the measurement points of the manhole cover C may be displayed in different colors.

[0067] In addition, the display color (e.g., red) of a manhole cover C that is determined to need replacement in the above replacement necessity determination may be different from the display color (e.g., blue) of a manhole cover C that does not need replacement.

[0068] 6 is a flowchart showing the control procedure of the manhole cover analysis control process executed by the processing device 200 of this embodiment. This manhole cover analysis control process is executed by a predetermined input operation by the user in a situation where the processing device 200 can access the measurement data of the measurement device 100, for example, after the vehicle W is driven and measurements are performed by the road surface measurement unit 110, the vehicle measurement unit 120, and the surroundings measurement unit 130.

[0069] The road surface measurement data acquisition means (control unit 210) acquires road surface measurement data from the measuring device 100 via the communication unit 230, and the control unit 210 acquires vehicle measurement data from the measuring device 100 via the communication unit 230 (step S101; road surface measurement data acquisition step). The control unit 210 acquires surrounding measurement data via the communication unit 230 (step S102). The order of acquisition of these three types of data acquired in steps S101 and S102 can be arbitrarily changed, and the data may also be acquired in parallel.

[0070] The control unit 210 executes an absolute position specifying process (to be described later) (step S103), thereby specifying the absolute positions of the road surface measurement data and the surroundings measurement data.

[0071] The area extraction means (control unit 210) extracts a manhole cover area based on the distribution of reflection intensity in the road surface measurement data (step S104; area extraction step, area extraction means). After detecting measurement points whose reflection intensity meets a criterion, the area extraction means groups them to determine a candidate area for the manhole cover, corrects closed areas within the candidate area, fits the corrected candidate area with a circle (ellipse), and extracts the area that meets the size and shape of the manhole cover as the manhole cover area.

[0072] The pattern height calculation means (control unit 210) removes the inclination component of the road surface by using a moving average or the like for each measurement point in the extracted manhole cover area (step S105).

[0073] The pattern height calculation means performs a correction to remove an outer edge that may include a frame from the manhole cover region, determines scanning lines (which may be measurement lines L) at a predetermined interval that pass through the corrected manhole cover region, and divides the region into local regions b by dividing the region along the scanning lines according to the appearance period of unevenness. The pattern height calculation means calculates the pattern height d from the maximum value of the difference in height between the top surface CT and the bottom surface CB (step S106). When the pattern heights d are obtained for all the divided local regions b, the pattern height calculation means determines, for each manhole cover region, the minimum value dmin of the obtained pattern heights d as the pattern height da representing that region (step S107).

[0074] The pattern height calculation means stores the identified pattern height da together with the measurement date and time in the database of the storage unit 220 (step S108). The control unit 210 determines whether or not a manhole cover C has already been identified in the same position based on the information on the measurement position, and if a manhole cover C has already been identified, stores the pattern height da and the measurement date and time in association with the data of the manhole cover C, and if a manhole cover C has not been identified in the same position, stores the data in the database of the storage unit 220 with further position information and a new identification code. The processing in steps S105 to S108 constitutes a pattern height calculation step (pattern height calculation means in the program) in the manhole cover measurement method and manhole cover analysis control method of the present invention.

[0075] The display control means (control unit 210) causes the display unit 241 to display the analysis information of the manhole cover C (step S109). The display control means may cause a balloon to display the position information, measurement date and time, pattern height da, and the like for the manhole cover C to be displayed. Then, the control unit 210 ends the manhole cover analysis control process.

[0076] The display control operation of step S109 may be executed separately from the analysis process up to step S108. That is, the display control process may be executed separately, a date and / or a location related to the analyzed data may be called up via the operation receiving unit 242, and an image based on the analyzed data may be displayed on the display screen of the display unit 241.

[0077] FIG. 7 is a flowchart showing a control procedure of the absolute position specifying process executed in step S103 of FIG. The relative positions of the road surface measuring unit 110 and the surroundings measuring unit 130 in the reference state (relative positions from the measurement reference position and heights from the road) and the initial attitude (attitude of the vehicle W at the start of measurement) are stored in advance in the memory unit 220. When the absolute position specifying process is started, the position specifying means (control unit 210) performs the processes of steps S201 to S209 by referring to the road surface measurement data, the vehicle measurement data, and the surroundings measurement data. The position identification means calculates a conversion function from date and time t1 to date and time t2 using the synchronization date and time t2(Tk) and the synchronization date and time t1(Tk) (step S201). The position identification means applies this conversion function to the road surface measurement date and time t1(j) to convert it into an absolute date and time (step S202).

[0078] The position specifying means calculates a measurement reference position (vehicle position) at each measurement date and time t1(j) by linear interpolation of the absolute positions before and after each measurement date and time t1(j) after the conversion of the positioning date and time t2(i) (step S203).

[0079] The position identification means sequentially adds up the results of the attitude measurement to calculate the attitude at measurement date and time t3(i), and calculates the vehicle attitude at the measurement date and time t1(j) by linear interpolation for attitudes that are before and after each measurement date and time t1(j) after the conversion (step S204).

[0080] The position specifying means calculates the measurement line at each measurement date and time t1(j) based on the measurement reference position, the initial attitude, the attitude of the vehicle, and the relative position of the road surface measuring unit 110 in the reference state (step S205). The position specifying means calculates the absolute position of the road surface height by adding the relative height measured at each measurement point at each measurement date and time t1(j) to the corresponding position on the measurement line at that date and time (step S206).

[0081] Instead of executing each process of steps S201 to S206 on the entire measurement data, each process of steps S201 to S206 on sections obtained by dividing the measurement data at predetermined times may be repeatedly executed the number of times equal to the number of sections.

[0082] Next, the position specifying means calculates the measurement reference position (vehicle position) at each surrounding measurement date and time t4(j) by linear interpolation for the absolute position where the positioning date and time t2(i) is before or after the measurement date and time t4(j) (step S207). Here, the date and time t4 may be used as it is because there is no difference between the date and time t2 and the date and time t4.

[0083] The position specifying means calculates the vehicle attitude at each measurement date and time t4(j) by linear interpolation for attitudes at measurement date and time t3(i) before and after the measurement date and time t4(j) (step S208).

[0084] The position identification means calculates the absolute position of each point (surrounding road surface) where the laser is reflected at each measurement date and time t4(j) based on the measurement reference position, initial attitude, vehicle attitude, relative position of the surrounding measurement unit 130 in the reference state, and surrounding measurement data (relative positions of surrounding objects with respect to the laser scanner 131) obtained at that measurement date and time t4(j) (step S209). Instead of executing the processes of steps S207 to S209 on the entire surrounding measurement data, the processes of steps S207 to S209 on sections obtained by dividing the measurement data at predetermined times may be repeatedly executed for the number of sections.

[0085] The position specifying means integrates the surrounding measurement data for a plurality of measurement dates and times t4(j) based on the absolute position (step S210). For example, the position specifying means performs integration such as excluding points where the horizontal position is less than a predetermined distance but the height difference is more than a predetermined value between different measurement dates and times, assuming that the data is data measuring a moving object. Points that cannot be obtained at some measurement dates and times due to shadows, etc. are supplemented with data obtained at other measurement dates and times. The conditions and standards for this integration judgment may be appropriately determined by utilizing well-known technologies, etc. As a result, three-dimensional road data 221 based on the surrounding measurement data is obtained. Then, the control unit 210 ends the absolute position specification process and returns the process to the manhole cover analysis control process.

[0086] FIG. 8 is a diagram showing an example of a display screen of a manhole cover analysis diagram as a display image. Here, the display image D1 in the display window displays a spatial distribution (central projection image) of each measurement point (including manhole cover C) included in the road surface measurement data as viewed from a specified viewpoint position (geographical three-dimensional position) as white dots. This display image is called a 3D view. The viewpoint position, line of sight and viewing angle may be interactively specified and adjusted, for example, through an input operation using a pointing device or the like (via a GUI (Graphical User Interface)). The line of sight and viewing angle (zoom ratio) may be specified by setting a virtual camera and specifying the orientation of its shooting surface and the focal length (the projection surface size, for example, full size, APS-C, etc., may be changeable). In other words, the display image D1 is a projection image projected onto the shooting surface of this virtual camera.

[0087] A horizontal cross-sectional view of the manhole cover C detected in the display image D1, cut slightly below the top surface CT, is shown in the display image D2. The height along the line LC passing through the center of the display image D2 is shown in the display image D3 as a transverse view equivalent to a vertical cross-sectional view in the width direction of the road surface. The positions of the cross-sections of the display images D2 and D3, the display width of the display image D2, and the scale and display width of the height shown in the display image D3 may be changeable by user operation or the like.

[0088] The display image D4 on the right is an image displayed to make it easier to identify the display position of the display image D1, and is a parallel projection image of the road surface measurement data viewed vertically from above. This display is called a 2D view. The manhole cover C may also be highlighted in this display image D4.

[0089] [Variations] The present invention is not limited to the above-described embodiment, but may be modified in various ways.

[0090] For example, in the above embodiment, one-dimensional local regions b are set, but it is also possible to set two-dimensional local regions b in which each local region includes unevenness. For example, the maximum width of the pattern may be estimated in advance, and the manhole cover region after the tilt removal may be divided into lattice-shaped regions of a predetermined size with one side larger than this maximum width, and each divided region may be set as local region b. Also, for example, the manhole cover region after the tilt removal may be divided into eight regions at a predetermined angle, for example, in units of 45 degrees, and each divided region may be set as local region b. In these cases, the maximum and minimum height values ​​are found in each local region b, and the difference between them is set as the pattern height.

[0091] Alternatively, the pattern height can be obtained by simply finding the difference between the maximum and minimum heights after the tilt is removed within the manhole cover region. The heights after the tilt is removed within the manhole cover region can be divided into two groups, a high side and a low side, and the pattern height can be determined as the difference between the minimum height of the high side group and the maximum height of the low side group. A histogram of the heights after the tilt is removed within the manhole cover region can be generated and divided into two regions, and the pattern height can be determined as the difference between the average values ​​or medians of the two regions.

[0092] In addition, in the above embodiment, the manhole cover C is divided so that the entire area is included in one of the local areas b, but one or more local areas b may include only a portion of the manhole cover C as a sample.

[0093] In the above embodiment, the minimum value dmin of the pattern heights d in the local region b of the manhole cover C is specified as the pattern height da representing the manhole cover C, but this is not limited to this. In order to reduce the influence of erroneous identification, the second smallest pattern height d may be set as the pattern height da, or the average value of a predetermined number of pattern heights in ascending order may be set as the pattern height da. Furthermore, the pattern height d may not be set as the maximum and minimum values ​​of the height within the position cycle of the irregularities, but may be set within a predetermined range based on a range of rapid change.

[0094] Furthermore, if garbage, fallen leaves, soil, sand, etc. have flowed into the manhole cover area, the reflection intensity of those areas will differ from the reflection intensity of the manhole cover, so such areas may be excluded from the calculation of the pattern height.

[0095] Also, while the manhole cover C related to the sewer system has been described, the manhole cover C referred to here may include covers that are located on the road for other purposes and are made of a different material than the road R (such as a metal cover). Such covers may include those related to fire hydrants and gas pipe routes, for example. When detecting other types of covers and identifying their wear conditions in this way, the shape of the fitting and the size to be determined may be determined according to the cover.

[0096] In the above embodiment, the measurement data is sent to the processing device 200 for processing after the measurement by the measuring device 100 is completed, but this is not limited to the above. The measurement data may be processed in real time or with a slight delay (collectively in approximately real time) while the measurement by the measuring device 100 is being performed. In this case, the communication unit 170 and the communication unit 230 may be connected via wireless communication or the like, or the processing device 200 may be located inside the vehicle W.

[0097] In the above description, the storage unit 220 consisting of a non-volatile memory such as an HDD is used as an example of a computer-readable medium for storing the program 222 related to the manhole cover analysis control of the present invention, but is not limited to this. As other computer-readable media, other non-volatile memories such as flash memory and MRAM, and portable recording media such as CD-ROM and DVD disks can be applied. In addition, a carrier wave is also applied to the present invention as a medium for providing data of the program related to the present invention via a communication line.

[0098] As described above, the manhole cover measurement system 1 of this embodiment comprises a measurement device 100 having a road surface measurement unit 110 that is mounted on a vehicle W and irradiates a laser beam onto the road surface on which the vehicle W travels, measures the height of the road surface at intervals according to the detection accuracy of the pattern height of the manhole cover C to be detected by the light cutting method, and outputs road surface measurement data including the height of each point on the road surface and the reflection intensity of the laser beam, and a processing device 200 having a control unit 210. The control unit 210 of the processing device 200 serves as area extraction means, extracting a manhole cover area using the reflection intensity of the irradiated laser beam, and serves as pattern height calculation means, calculating the manhole cover C and the pattern height da representing the manhole cover C from the height difference within the extracted manhole cover area. In this way, the manhole cover measurement system 1 uses the light cutting method to measure the unevenness caused by the pattern on the surface of the manhole cover C, so it can obtain the pattern height d and pattern height da with high accuracy. In particular, since the laser light is irradiated from the traveling vehicle W and the reflected light is detected, the measurement is not affected by shadows caused by sunlight and can be performed regardless of the presence or absence of other traveling vehicles. Therefore, this manhole cover measurement system 1 can more accurately and efficiently determine the degree of wear of the manhole cover.

[0099] Furthermore, the control unit 210, as a pattern height calculation means, calculates the difference between the maximum and minimum heights in at least a portion of the manhole cover area as the pattern height d and the pattern height da. The pattern height can be calculated with high accuracy using the heights corresponding to the top surface CT and bottom surface CB of the pattern on the manhole cover C.

[0100] Furthermore, the control unit 210, as a pattern height calculation means, defines multiple local regions b and specifies the minimum of the pattern heights d obtained for each as the pattern height da representing the manhole cover region. Wear of the pattern on the manhole cover C tends to be uneven depending on the traveling position of passing vehicles, etc. By dividing the range of the manhole cover C into multiple local regions b and obtaining the pattern height d for each, the manhole cover measurement system 1 can properly specify the degree of wear even when wear has progressed locally. It can also specify the state of such uneven wear.

[0101] The manhole cover measurement method of this embodiment includes a road surface measurement step in which a laser beam is irradiated onto the road surface on which the vehicle W is traveling, the height of the road surface is measured at intervals according to the detection accuracy of the pattern height of the manhole cover C to be detected by the light cutting method, and road surface measurement data including the height of each point on the road surface and the reflection intensity of the laser beam is output, an area extraction step in which a manhole cover area is extracted using the reflection intensity of the irradiated laser beam, and a pattern height calculation step in which the pattern height d of the manhole cover C and the pattern height da representing the manhole cover C are calculated based on the height difference within the extracted manhole cover area. In identifying the degree of wear of the manhole cover C using the measurement results by such a light cutting method, the distribution of the height of the road surface can be easily and accurately measured while the vehicle W is traveling, and the manhole cover area and the road surface can be distinguished. Therefore, according to this manhole cover measurement method, the degree of wear of the manhole cover can be accurately and efficiently determined.

[0102] Moreover, the processing device 200, which is an embodiment of the manhole cover information analysis device, includes road surface measurement data acquisition means (control unit 210) that acquires road surface measurement data from the road surface measurement unit 110 of the measuring device 100, area extraction means (control unit 210) that extracts a manhole cover area using the reflection intensity of the irradiated laser light, and pattern height calculation means (control unit 210) that calculates the pattern height d of the manhole cover C and the pattern height da representing the manhole cover C from the height difference within the extracted manhole cover area. In this way, by specifying the height of the pattern (unevenness) of the manhole cover C using the measurement results obtained by the light cutting method and analyzing the degree of wear, the processing device 200 can accurately and efficiently acquire the degree of wear of the manhole cover.

[0103] Furthermore, the manhole cover analysis control method of this embodiment includes a road surface measurement data acquisition step of acquiring road surface measurement data from the road surface measurement unit 110, an area extraction step of extracting a manhole cover area using the reflection intensity of the irradiated laser light, and a pattern height calculation step of calculating the pattern height d of the manhole cover C and the pattern height da representing the manhole cover C from the height difference within the extracted manhole cover area. This type of analysis processing method can also accurately and efficiently determine the degree of wear of the manhole cover.

[0104] In addition, the program 222 of this embodiment can cause the computer to function as a road surface measurement means, an area extraction means, and a pattern height calculation means in the procedure of the manhole cover analysis control method. Therefore, by executing this program 222, the degree of wear of the manhole cover can be accurately and efficiently determined by software processing of the computer.

[0105] In addition, the specific configurations, contents and procedures of the processing operations, etc. shown in the above embodiments can be modified as appropriate without departing from the spirit of the present invention. The scope of the present invention includes the scope of the invention described in the claims and its equivalents. [Explanation of symbols]

[0106] 1. Manhole cover measurement system 100 Measuring Equipment 110 Road surface measurement section 111 Irradiation unit 1111 Light emitting part 1112 Scanning unit 112 Photography Department 113 Timing section 1221 Acceleration Sensor 1222 Gyro sensor 120 Vehicle Measurement Department 121 Satellite Positioning Unit 122 Posture measurement unit 123 Timing section 130 Circumference measurement unit 131 Laser Scanner 140 Synchronous signal output section 150 Control section 160 Storage section 170 Communications Department 200 Processing equipment 210 Control section 220 Storage section 221 3D road data 222 Program 230 Communications Department 240 Input / output section 241 Display section 242 Operation reception section C Manhole cover CB bottom CT top surface D1~D4 Display image L Measurement line R road Ra pavement surface U Manhole W Vehicle

Claims

1. a road surface measurement means mounted on a vehicle, which repeatedly irradiates a laser beam in a curtain-like pattern onto a road surface on which the vehicle is traveling, measures the height of the road surface along a measurement side line for each irradiation of the laser beam at intervals corresponding to the detection accuracy of a pattern height, which is the difference in height of the projections and recesses of a pattern on a manhole cover to be detected by a light cutting method, and outputs road surface measurement data including the height of each point on the road surface and the reflection intensity of the laser beam; an area extraction means for extracting a manhole cover area using the reflection intensity; a pattern height calculation means for calculating the pattern height of the manhole cover based on the height difference within the extracted manhole cover area; Equipped with The pattern height calculation means defines local regions along each of the plurality of measurement side lines within the manhole cover region, and calculates the difference between the maximum value and the minimum value of the height in the local region as the pattern height. A manhole cover measurement system.

2. The manhole cover measurement system according to claim 1 , wherein the pattern height calculation means identifies the minimum value of the height differences obtained in each of the local regions as the pattern height representative of the manhole cover region.

3. a road surface measurement step in which a laser beam is mounted on a vehicle and repeatedly irradiated in a curtain-like manner onto a road surface on which the vehicle is traveling, and a height of the road surface along a measurement side line for each irradiation of the laser beam is measured at intervals corresponding to a detection accuracy of a pattern height, which is a difference in height of the unevenness of a pattern of a manhole cover to be detected by a light cutting method, and road surface measurement data including the height of each point on the road surface and the reflection intensity of the laser beam is output; A region extraction step of extracting a manhole cover region using the reflection intensity; a pattern height calculation step of calculating the pattern height of the manhole cover based on the height difference within the extracted manhole cover area; Including, In the pattern height calculation step, a local area is defined along each of the plurality of measurement side lines within the manhole cover area, and a difference between a maximum value and a minimum value of the height in the local area is calculated as the pattern height. A manhole cover measurement method comprising:

4. a road surface measurement data acquisition means which is mounted on a vehicle and repeatedly irradiates a laser beam in a curtain-like manner onto a road surface on which the vehicle is traveling, measures the height of the road surface along a measurement side line for each irradiation of the laser beam at intervals corresponding to the detection accuracy of a pattern height, which is the difference in height of the unevenness of a pattern of a manhole cover to be detected by a light cutting method, and acquires the road surface measurement data from a road surface measurement means which outputs road surface measurement data including the height of each point on the road surface and the reflection intensity of the laser beam; A region extraction means for extracting a manhole cover region using the reflection intensity; a pattern height calculation means for calculating the pattern height of the manhole cover based on the height difference within the extracted manhole cover area; Equipped with The pattern height calculation means defines local regions along each of the plurality of measurement side lines within the manhole cover region, and calculates the difference between the maximum value and the minimum value of the height in the local region as the pattern height. A manhole cover information analysis device characterized by the above.

5. a road surface measurement data acquisition step of acquiring road surface measurement data from a road surface measurement means which is mounted on a vehicle and repeatedly irradiates a laser beam in a curtain-like manner onto a road surface on which the vehicle is traveling, measures a height of the road surface along a measurement side line for each irradiation of the laser beam at intervals corresponding to a detection accuracy of a pattern height, which is a difference in height of the unevenness of a pattern of a manhole cover to be detected by a light cutting method, and outputs road surface measurement data including the height of each point on the road surface and the reflection intensity of the laser beam; A region extraction step of extracting a manhole cover region using the reflection intensity; a pattern height calculation step of calculating the pattern height of the manhole cover based on the height difference within the extracted manhole cover area; Including, In the pattern height calculation step, a local area is defined along each of the plurality of measurement side lines within the manhole cover area, and a difference between a maximum value and a minimum value of the height in the local area is calculated as the pattern height. A manhole cover analysis and control method comprising:

6. Computer, a road surface measurement means which is mounted on a vehicle and repeatedly irradiates a laser beam in a curtain-like manner onto a road surface on which the vehicle is traveling, measures the height of the road surface along a measurement side line for each irradiation of the laser beam at intervals corresponding to the detection accuracy of a pattern height, which is the difference in height of the unevenness of a pattern of a manhole cover to be detected by a light cutting method, and acquires the road surface measurement data from the road surface measurement means which outputs road surface measurement data including the height of each point on the road surface and the reflection intensity of the laser beam; an area extraction means for extracting a manhole cover area using the reflection intensity; a pattern height calculation means for calculating the pattern height of the manhole cover based on the height difference within the extracted manhole cover area; Function as a The pattern height calculation means defines local regions along each of the plurality of measurement side lines within the manhole cover region, and calculates the difference between the maximum value and the minimum value of the height in the local region as the pattern height. A program characterized by:

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