JP2011122851A - Method and device for detecting object - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve accurate object detection using data related to the reflected light of a scanning light corresponding to an entire monitored area, without using the scanning position of the scanning light on the monitored area as a reference. <P>SOLUTION: The method for detecting an object includes: a step of receiving measured data D generated by a signal processing unit 3 with a control device 6 by packet communication; a step of detecting an object existing on the scanning lines from the measured data D corresponding to the received scanning lines of predetermined number, each time the measured data D are stored in a corresponding address location of a measured data memory area 64a; and a step of detecting the object existing in a scanned range E using the latest 1 frame equivalent object detection data stored in an analysis result memory area 64b. The data amount of the measured data D received by the control device 6 from the signal processing unit 3 by one packet communication can be the data amount coinciding to the measured data D equivalent to one scanning line. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method and an apparatus for detecting an object existing in a monitoring area such as in a railroad crossing.

  The technology for detecting objects in the monitoring area by scanning the three-dimensional space with the scanning light for distance measurement in the main scanning direction and the sub-scanning direction and analyzing the reflected light It is also used in the field (for example, Patent Document 1).

  In order to scan the scanning light in the main scanning direction and the sub-scanning direction, a polygon mirror and a galvanometer mirror are generally used in combination. In this case, for example, scanning light emitted from a light source such as a laser light source is scanned in the main scanning direction by a polygon mirror, and further, scanning light in the main scanning direction is scanned in the sub scanning direction by a galvano mirror. .

Japanese Patent No. 4279302

  In order to detect an object by analyzing the reflected light of the scanning light described above, data relating to the reflected light of the scanning light is required for the entire monitoring region. Therefore, it is conceivable to acquire the data related to the reflected light of the scanning light for the entire monitoring area with the scanning end of the scanning light in the sub-scanning direction as a break.

  As for the scanning end of the scanning light in the sub-scanning direction, the oscillating end of the galvano mirror is physically detected by a sensor, and the oscillating position of the control galvano mirror calculated from the drive signal of the motor no longer changes. Can be recognized. However, if the motor reduces the rotation speed near the oscillating end of the galvano mirror by servo control, the galvano mirror stops instantaneously near the oscillating end due to the friction of the bearing, and then slightly again to the original oscillating end. May swing. When such a momentary stop of the galvano mirror before the swing end occurs, an erroneous detection that the galvano mirror has reached the swing end occurs, and the scanning light reaches the scanning end in the sub-scanning direction. It may be mistakenly recognized as a thing.

  Therefore, in order to use the scanning end of the scanning light in the sub-scanning direction for the detection of the object detection by the reflected light of the scanning light, it is necessary to take measures for the possibility of erroneous detection as described above. Taking such measures leads to a complicated configuration for recognizing the scanning end of the scanning light in the sub-scanning direction.

  As described above, when the position of the scanning light on the monitoring area is detected and the data on the reflected light of the scanning light corresponding to the entire monitoring area is acquired based on the detected position, the scanning light on the monitoring area is obtained. It is essential to take measures to avoid the influence of the position detection accuracy.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to obtain data relating to reflected light of scanning light corresponding to the entire monitoring area without using the scanning position of the scanning light on the monitoring area as a reference. An object of the present invention is to provide an object detection method and apparatus capable of realizing accurate object detection.

  In order to achieve the above object, the object detection method of the present invention described in claim 1 scans the entire monitoring region by scanning light that sequentially scans a plurality of scanning lines, and the monitoring by reflected light of each scanning light. In the method of detecting an object present in an area, each time the scanning light scans a predetermined number of scanning lines that are smaller than the number of scanning lines located on the monitoring area, the latest scanning light of each scanning line is detected. An object existing in the monitoring area is detected based on reflected light.

  In order to achieve the above object, an object detection apparatus according to a third aspect of the present invention includes a laser radar that scans the entire monitoring area with scanning light that sequentially scans a plurality of scanning lines, Object detection means for detecting an object present in the monitoring area based on the reflected light of each scanning light respectively scanned on each scanning line located on the scanning line, and on each scanning line located on the monitoring area, respectively. Each time the scanning light scans reflected light data storage means for storing reflected light data of the latest scanned light and a predetermined number of scanning lines which are smaller than the number of scanning lines located on the monitoring area. Based on the latest reflected light data of each scanning light scanned on each scanning line stored in the reflected light data storage means, the object detection means detects an object present in the monitoring area. Characterized in that it comprises a control means for causing out.

  According to the object detection method of the present invention described in claim 1 and the object detection apparatus of the present invention described in claim 3, every time scanning light scans a predetermined number of scan lines, the predetermined number of scans. An object existing in the monitoring area is detected based on the latest reflected light of each scanning light scanned on a plurality of scanning lines on the monitoring area including the line. Here, since the predetermined number is smaller than the number of scanning lines located on the monitoring area, the period in which the object detection of the monitoring area is performed based on the reflected light of each scanning light is performed from the end of the monitoring area. It does not synchronize with the cycle of finishing scanning all the scanning lines to the end.

  Therefore, in order to recognize the timing at which the scanning light finishes scanning on all the scanning lines from the end to the end of the monitoring area, the scanning light reaches the end of the monitoring area in the row direction perpendicular to the extending direction of the scanning lines. There is no need to detect that. For this reason, even when it is difficult to detect the scanning position of the scanning light on the monitoring area with high accuracy, the data regarding the reflected light of the scanning light corresponding to the entire monitoring area is used without being affected by the detection. Accurate object detection can be realized.

  Furthermore, the object detection method of the present invention described in claim 2 is the object detection method of the present invention described in claim 1, wherein the predetermined number is one. According to a fourth aspect of the present invention, in the object detection device of the present invention described in the third aspect, the predetermined number is one.

  According to the object detection method of the present invention described in claim 2 and the object detection device of the present invention described in claim 4, the object detection method of the present invention described in claim 1 and claim 3 In the object detection apparatus of the present invention, each time scanning light scans each scanning line on the monitoring area, object detection is performed based on the reflected light of the scanning light for the entire monitoring area. For this reason, an object that moves at high speed with respect to a period in which the scanning light scans all the scanning lines from end to end of the monitoring area is not affected by the detection position detection accuracy of the scanning light on the monitoring area. Thus, it is possible to realize object detection using data relating to the reflected light of the scanning light corresponding to the entire monitoring area.

  According to the present invention, it is possible to acquire data related to the reflected light of the scanning light corresponding to the entire monitoring area without using the scanning position of the scanning light on the monitoring area as a reference. For this reason, even when it is difficult to detect the scanning position of the scanning light on the monitoring area with high accuracy, the data regarding the reflected light of the scanning light corresponding to the entire monitoring area is used without being affected by the detection. Accurate object detection can be realized.

It is a schematic block diagram which shows the object detection apparatus which concerns on one Embodiment of this invention to which the object detection method by this invention is applied. FIG. 2 is a perspective view for explaining a bird's-eye view of an installation environment of a laser radar head when the object detection apparatus of FIG. 1 is used for crossing obstacle detection. (A), (b) is explanatory drawing which shows the scanning line of the scanning light radiate | emitted from the laser radar head of FIG. It is explanatory drawing which shows typically the irradiation point of the scanning light in case the scanning light by which intermittent light emission is scanned on the scanning line of FIG.3 (b). It is explanatory drawing which shows the determination method whether the reflected light of the scanning light received in the plurality of points is from the same object. It is explanatory drawing which shows the detection method of the object based on the reflected light of scanning light. It is explanatory drawing which shows the method of judging the difference of the detected object. It is a flowchart of the process which the control apparatus of FIG. 1 performs. It is a top view which shows the relationship between the scanning range of a level crossing by the scanning light from the laser radar head installed in the location of FIG. 2, and the obstruction monitoring area.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic configuration diagram showing an object detection apparatus according to an embodiment of the present invention to which an object detection method according to the present invention is applied.

  The object detection apparatus shown in FIG. 1 scans an area to be monitored with scanning light and detects an object in the area by reflected light. The laser radar head 5 outputs scanning light and receives the reflected light. And a control device 6 that performs detection processing of an object in the area based on the scanning light and the reflected light.

  When the object detection apparatus of FIG. 1 is used, for example, for detecting an obstacle at a level crossing, the laser radar head 5 is located near the upper end of a column B standing near the level crossing A as shown in a perspective view in the perspective view of FIG. Installed in the installation. By installing the laser radar head 5 at such a high place, the scanning light from the laser radar head 5 can be scanned with the scanning light in an area where the vehicle C or a passerby (not shown) enters the railroad crossing A. . 2 schematically shows the scanning range E by the scanning light from the laser radar head 5.

  As shown in FIG. 1, the laser radar head 5 includes a light projecting unit 1 that outputs a laser beam L, a polygon mirror 11 and a galvanometer mirror that scan the laser beam L in the horizontal and vertical directions to obtain a scanning beam L1. 12, a light receiving unit 2 that receives reflected light L2 of the scanning light L1 irradiated on the object after being reflected by the galvanometer mirror 12 and the polygon mirror 11, a light projection window W through which the scanning light L1 and the reflected light L2 pass, A signal processing unit 3 that generates measurement data D necessary for object detection from information on the scanning light L1 and the reflected light L2 obtained from the light unit 1 and the light receiving unit 2; The signal processing unit 3 includes a main signal processing unit 31 and a time measurement unit 32.

  The light projecting unit 1 includes a laser diode 1a serving as a light source, a light projecting lens 1b for collimating the laser light L, and an LD driver 1c for operating the laser diode 1a. The LD driver 1c operates the laser diode 1a so as to intermittently emit the laser light L based on the trigger signal St from the signal processing unit 3, and a pulsed light projection synchronization signal Ss synchronized with the intermittent light emission of the laser light L. Is transmitted to the signal processing unit 3. Note that the projection synchronization signal Ss may be substituted by the trigger signal St.

  The polygon mirror 11 has a hexahedron that rotates at high speed, and is configured to be rotated by a motor 11a with the center of two opposing surfaces (upper and lower surfaces) excluding the mirrored four side surfaces as a rotation axis. Yes. The motor 11a is operated by a motor driver 11b. The laser beam L is reflected by any one of the four side surfaces of the polygon mirror 11, whereby the laser beam L is scanned in the main scanning direction (horizontal scanning direction).

  The galvanometer mirror 12 is connected to a side surface of a rotating shaft that is reciprocally rotated by a motor 12a within a limited angle range, and is reciprocally swung by the reciprocating rotation of the rotating shaft. The motor 12a is operated by a motor driver 12b. The laser beam L is reflected by one surface of the galvanometer mirror 12 so that the laser beam L is scanned in the sub-scanning direction (vertical scanning direction).

  The motor drivers 11b and 12b of the polygon mirror 11 and the galvano mirror 12 are controlled by a control signal Sm from the signal processing unit 3. Further, the motor drivers 11 b and 12 b transmit a light projection condition signal Sc such as a rotation angle of the polygon mirror 11 and a swing angle of the galvanometer mirror 12 to the signal processing unit 3. The polygon mirror 11 and the galvanometer mirror 12 described above are merely examples, and the scanning optical system for the laser light L is not limited to the illustrated configuration.

  Incidentally, when the laser light L is scanned in the horizontal and vertical directions by the polygon mirror 11 and the galvanometer mirror 12 described above, the scanning light L1 is scanned on the scanning lines as shown in FIGS. Specifically, when the galvano mirror 12 swings from the elevation side to the depression side, as shown in FIG. 3A, the scanning light L1 scans on an oblique scanning line from the upper left to the lower right. . On the contrary, when the galvanometer mirror 12 swings from the depression angle side to the elevation angle side, as shown in FIG. 3B, the scanning light L1 is scanned on an oblique scanning line from the lower left to the upper right. Hereinafter, for convenience, FIG. 3A may be referred to as a forward scanning line, and FIG. 3B may be referred to as a backward scanning line.

  Since both the forward scanning line and the backward scanning line have a slight inclination with respect to the horizontal, in the operation, it is assumed that each scanning line in the forward path and each scanning line in the backward path scan the same part. . Then, the scanning lines for one frame of the scanning range E are configured by setting all the scanning lines (50 in this embodiment) from the upper end to the lower end of the vertical scanning range as a set.

  Note that, in both cases of the forward path and the backward path, the scanning line interval is shorter near the upper end and lower end of the vertical scanning range than at other portions. This is because the motor driver 12b of the galvano mirror 12 servo-controls the motor 12a, so that the rotational speed of the motor 12a or the swing speed of the galvano mirror 12 decreases near the upper end and the lower end of the vertical scanning range. is there.

  As described above, since the LD driver 1c emits light intermittently based on the trigger signal St as described above, when the scanning light L1 scans the scanning line described above. In this case, the scanning light L1 is irradiated at locations at regular intervals on the scanning line. For example, when the scanning light L1 scans the scanning line on the return path shown in FIG. 3B, the points P0 to Pn at regular intervals on the scanning line are schematically shown by the white circles in the explanatory diagram of FIG. , The scanning light L1 is irradiated toward the scanning range E (see FIG. 2). When the scanning light L 1 is irradiated on the object in the scanning range E, the reflected light L 2 from the object (a part of the reflected light L 2) travels toward the projection window W of the laser radar head 5.

  As shown in FIG. 1, the light receiving unit 2 includes a light receiving lens 2 a that condenses the reflected light L <b> 2 that passes through the projection window W and is guided to the light receiving unit 2 by reflection by the galvanometer mirror 12 and the polygon mirror 11. It has a light receiving part main body 2b having a photoelectric conversion element such as a photodiode for receiving the reflected light L2 and converting it into a voltage, an amplifier, and the like. Then, the light receiving unit main body 2b that receives the reflected light L2 transmits a light receiving signal Sr converted into a voltage value to the signal processing unit 3.

  The time measuring unit 32 of the signal processing unit 3 has a clock function for measuring time, starts measuring time by receiving the light projection synchronization signal Ss from the LD driver 1c of the light projecting unit 1, and receives light. The time when the light receiving signal Sr from the light receiving unit main body 2b of the unit 2 is received is grasped. Therefore, the time measuring unit 32 can measure the time required from when the scanning light L1 is emitted from the light projecting unit 1 until the reflected light L2 applied to the object is received by the light receiving unit 2. Further, the time measuring unit 32 may have a discrimination function for selecting a light reception signal Sr having a desired light reception intensity from the light reception signal Sr, and a gate function for excluding those having a short required time from the light reception signal Sr. . Such discrimination function and gate function can efficiently eliminate noise. Then, the time measuring unit 32 transmits the received light intensity signal Sq and the required time signal Sd of the received light signal Sr that has passed through the discrimination function and the gate function to the main signal processing unit 31.

  The main signal processing unit 31 of the signal processing unit 3 transmits a trigger signal St to the LD driver 1c of the light projecting unit 1, transmits control signals Sm to the motor drivers 11b and 12b of the polygon mirror 11 and the galvano mirror 12, and a motor driver. Processes such as reception of light projection condition signals Sc from 11b and 12b, reception of signals (light reception intensity signal Sq and required time signal Sd) from time measurement unit 32, generation of measurement data D, and transmission to control device 6 are performed. .

  The measurement data D (corresponding to the reflected light data in the claims) includes data obtained from the scanning light L1 and the reflected light L2. Specifically, the measurement data D is obtained from the laser radar head 5 to the reflection point of the scanning light L1 obtained by converting the required time signal Sd by the calculation formula of (light speed) × (required time) / 2. It includes distance data indicating the distance, a received light intensity signal Sq from the time measuring unit 32, a light projection condition signal Sc from the motor drivers 11b and 12b, and the like. The measurement data D is generated for each point P0 to Pn on each scanning line. The measurement data D generated by the main signal processing unit 31 is accumulated in a buffer memory (not shown) of the signal processing unit 3.

  The measurement data D is output to the control device 6 by packet communication, for example, every time a predetermined amount is accumulated in the buffer memory (not shown). Measurement of the measurement data D obtained from the scanning light L1 and the reflected light L2 for one scanning line in the forward path or the backward path shown in FIGS. 3A and 3B or a data amount close to it in one packet communication. Data D is transmitted to the control device 6. The measurement data D includes address information indicating which point P0 to Pn of which scanning line is the data.

  The control device 6 is a computer having an image processing unit 61, a failure diagnosis unit 62, an error correction unit 63, and the like. The image processing unit 61 transmits control conditions Sh for the light projecting unit 1, the polygon mirror 11, and the galvanometer mirror 12 to the signal processing unit 3. Under this control condition Sh, the rotation angle and rotation speed of the polygon mirror 11, the swing angle and swing speed of the galvano mirror 12, and the laser light from the main signal processing unit 31 of the signal processing unit 3 to the LD driver 1 c of the light projecting unit 1. Conditions such as the transmission timing of the L trigger signal St are set. Therefore, the contents of the trigger signal St of the LD driver 1c and the control signal Sm of the motor drivers 11b and 12b transmitted from the main signal processing unit 31 of the signal processing unit 3 are determined based on the control condition Sh.

  Further, the image processing unit 61 analyzes the measurement data D relating to the scanning line for one frame in the scanning range E received by the control device 6 from the signal processing unit 3, and the object present in the scanning range E is determined from the analysis result. To detect. Further, the image processing unit 61 collates the above-described analysis result with the latest analysis result for the past plural frames, and determines the stationary or moving state of the object existing in the scanning range E. Then, the control device 6 outputs the detection result of the object and the determination result of the stationary or moving state to the output device 7 such as a display, a printer, or an alarm device.

  In order to realize the above processing of the image processing unit 61, the control device 6 includes a RAM 64. The RAM 64 has a measurement data storage area 64a (corresponding to the reflected light data storage means in the claims) for storing the latest measurement data D for each scanning line of the scanning range E, and past analysis results. And an analysis result storage area 64b for storing.

  The measurement data storage area 64a has addresses corresponding to the scanning lines of the scanning range E and the points P0 to Pn. Therefore, when the control device 6 receives the measurement data D from the signal processing unit 3 by packet communication, the received measurement data D is stored in the measurement data storage area 64a corresponding to the scanning line and the points P0 to Pn indicated by the address information. Is stored at the address location. If the measurement data D is already stored at the address location of the storage destination, the received measurement data D is overwritten and stored as the latest data. As a result, the latest measurement data D relating to the scanning lines for one frame of the scanning range E is stored in the measurement data storage area 64a.

  In the analysis result storage area 64b, the data of the object existing on the scanning line detected by analyzing the measurement data D received each time the image processing unit 61 receives the measurement data D is stored for at least the latest two frames. Is done.

  In the failure diagnosis unit 62, an error detection device (not shown) provided in the laser radar head 5 is used to detect the error of the distance data obtained from the required time signal Sd by the main signal processing unit 31 of the signal processing unit 3. When the error exceeds a certain value, a failure signal is output to the output device 7. The failure diagnosis unit 62 detects an error in the received light intensity of the reflected light L2 indicated by the received light intensity signal Sq from the time measuring unit 32 of the signal processing unit 3 using the above-described equipment (not shown). When the value exceeds a certain value, a function of outputting a failure signal to the output device 7 can be provided. In the error correction unit 63, a correction value for correcting an error in distance data by the failure diagnosis unit 62 is calculated. This correction value is fed back to the image processing unit 61 and used for correcting the distance data in the measurement data D by the image processing unit 61. Instead of feeding back the error value to the image processing unit 61, the signal processing unit 3 notifies the signal processing unit 3 according to the control condition Sh, and the signal processing unit 3 corrects the distance data in the measurement data D before being output to the control device 6. You may comprise so that it may utilize.

  The image processing unit 61 of the control device 6 having the above-described configuration is the measurement data D generated from the scanning light L1 that scans the entire scanning range E on the scanning line of the forward path or the backward path and the reflected light L2. Is detected in units of one frame of the scanning range E, thereby detecting an object existing in the scanning range E. Then, by repeating this detection, the stationary or moving state of the object existing in the scanning range E is determined.

  Here, based on the measurement data D for one packet communication from the signal processing unit 3, the image processing unit 61 detects an object present on the scanning line corresponding to the measurement data D as follows. That is, the scanning light L1 irradiated to the scanning range E at each point P0 to Pn of the scanning line is reflected by the object in the scanning range E, and the reflected light L2 from the object is received by the light receiving unit 2 (see FIG. 1). If the reflected light L2 of the scanning light L1 irradiated at the continuous points P0 to Pn is received by the light receiving unit 2, the image processing unit 61 scans the scanning light L1 at the respective points P0 to Pn before and after the continuous. Are reflected from the same object.

  In this determination, the image processing unit 61 uses the measurement data D generated from each scanning light L1 and each reflected light L2 corresponding to the position where the scanning light L1 is reflected at each of the front and rear points P0 to Pn. Use to identify. The distance between the reflection positions of the scanning light L1 with respect to the specified points P0 to Pn before and after the specified position is determined in each of the XY directions (horizontal scanning direction and vertical scanning direction) as shown in the explanatory diagram of FIG. When both are within the respective threshold values, the image processing unit 61 determines that the scanning light L1 is reflected by the same object at each of the points P0 to Pn before and after consecutive. On the other hand, when the distance between the reflection positions of the scanning light L1 with respect to each point P0 to Pn exceeds the threshold value in the corresponding direction in any of the X and Y directions, the image processing unit 61 continuously At the points P0 to Pn before and after the scanning, it is determined that the scanning light L1 is reflected by different objects.

  Such a determination is made when the scanning light L1 irradiated to the respective points P0 to Pn before and after the continuous is reflected by different snowflakes during snowfall and continuously received by the light receiving unit 21. This is to prevent erroneous determination of the reflected light L2 from the same object. Further, since the distance between the adjacent points P0 to Pn increases as the distance from the laser radar head 5 increases, the threshold values in the X and Y directions described above are indicated by the distance data of the measurement data D. Is set to a different value according to the distance from the reflection point of the scanning light L1.

  Specifically, a constant α (α = λ ÷ (2 × maximum snow measurement distance)) obtained by dividing the distance λ from the laser radar head 5 to the reflection point of the scanning light L1 by twice the maximum snow measurement distance is a snowflake. The threshold values in the X and Y directions described above are set to different values depending on whether the reflected light L2 of the scanning light L1 is less than “1” that can be received by the light receiving unit 2 or is “1” or more that cannot be received. To do. The snow measurement maximum distance is the maximum distance at which the reflected light L2 of the scanning light L1 reflected by the snowflake can be received by the light receiving unit 2. The maximum snow measurement distance is determined depending on the reflectance of the snowflake and the light receiving sensitivity of the light receiving unit 2, but can be set to an empirically or experimentally determined value if it cannot be determined quantitatively.

  If the constant α is less than 1, the threshold value in the X direction is set to a value obtained by multiplying the size correction value [width] by twice the constant α, and the threshold value in the Y direction is set as the short distance detection length. Set to. On the other hand, when the constant α is 1 or more, the threshold value in the X direction is set to a value twice the size correction value [width], and the threshold value in the Y direction is set as the size correction value [length].

  Here, the size correction value [width] used for the threshold value in the X direction is the adjacent points P0 to Pn at the maximum distance (30 m in the present embodiment) at which the object can be detected by the scanning light L1 and the reflected light L2. The distance between the two is set to 0.2 m in this embodiment.

  In addition, the short distance detection length used for the threshold value in the Y direction assumes the case where the object to be detected is a vehicle, and is the dimension in the height direction of the average windshield and rear glass of the vehicle (in this embodiment, 0.5m). This short distance detection length is used in order to prevent erroneous determination that the hood, trunk portion and roof portion of the vehicle are separate objects. That is, the reflected light L2 of the scanning light L1 is received by the light receiving unit 2 at the hood or trunk portion of the vehicle, but the reflected light L2 is not received by the light receiving unit 2 because the scanning light L1 is not reflected by the windshield or rear glass portion. After that, when the reflected light L2 of the scanning light L1 is received again by the light receiving unit 2 at the roof portion, the bonnet, the trunk portion, and the roof portion are erroneously recognized as separate objects.

  Further, the size correction value [length] used for the threshold value in the Y direction is set to a value twice the reference value (1 m in the present embodiment) relating to the depth of the object to be detected. The magnitude correction value [length] is used because the depth of the object to be detected cannot be measured by the measurement data D. The constant α described above receives the reflected light L2 of the scanning light L1 from the snowflakes as the light receiving unit 2. It is used when “1” or more cannot be received.

  Using the threshold value described above, it is determined whether or not the reflected light L2 continuously received by the light receiving unit 2 is reflected light L2 from the same object existing on the scanning line. Then, as shown in the explanatory diagram of FIG. 6, the reflected light L2 is received by the light receiving unit 2 continuously for a plurality of times (group 1, group 2) at least once, and continuously for a plurality of times. When it is determined that the reflected light L2 received by the light receiving unit 2 is reflected light L2 from the same object, the point where the reflected light L2 is not received by the light receiving unit 2 is sandwiched. It is recognized that the reflected light L2 received by the light receiving unit 2 continuously several times before and after is reflected light L2 from different objects.

  Thus, after determining whether or not the reflected light L2 is from the same object on the scanning line, the image processing unit 61 specifies the planar shape of the object on the scanning line. In specifying the planar shape of the object, when the points P0 to Pn recognized as the reflected light L2 from the same object on the scanning line are one point, the image processing unit 61 centers the points P0 to Pn. Each having a width of the size correction value [width] in the X direction (horizontal scanning direction), a depth of the size correction value [length] in the Y direction (vertical scanning direction), and the Z direction (vertical direction) ) Is converted into data as an object having a height with the points P0 to Pn as vertices. In addition, when there are a plurality of points P0 to Pn recognized as the reflected light L2 from the same object on the scanning line, the image processing unit 61 sets the points P0 to P0 at both ends in the X direction (horizontal scanning direction). It has a width between Pn, has a depth corresponding to a size correction value [length] from the point points P0 to Pn closest to the laser radar head 5 in the Y direction (vertical scanning direction), and Z direction (vertical direction) Is converted into data as an object having a height with vertices at points P0 to Pn at the highest position.

  In addition, the image processing unit 61 determines the object (the object specified last time) identified based on the measurement data D received from the signal processing unit 3 in the previous packet communication and the measurement received from the signal processing unit 3 in the current packet communication. Differences from the object specified based on the data D (the object specified this time) are determined as follows. That is, as shown in FIG. 7, when the object specified last time and the object specified this time partially overlap each other in the XY directions, the two objects are combined and recognized as one object. Further, if the combined object overlaps with the object specified this time or the object specified last time even in a part in each of the XY directions, the two objects are further combined and recognized as one object. When two objects are combined in this way, the object after combining the two objects is the point P0 at the most end in the X direction (horizontal scanning direction) among the points P0 to Pn of the two objects before combining. Has a width between .about.Pn, has a depth between points P0 to Pn at both ends in the Y direction (vertical scanning direction), and has the highest points P0 to Pn in the Z direction (vertical direction) as vertices. It is converted into data as an object having a height.

  Then, the image processing unit 61 can detect an object existing in the scanning range E by executing an analysis for performing the above-described processing on the measurement data D related to the scanning line for one frame in the scanning range E. Further, the image processing unit 61 periodically repeats such an analysis, and the difference between the object detected in the previous analysis and the object detected in the current analysis is similar to the method shown in FIG. Judge using In other words, an area indicating the range in which the object is likely to move is added around the object detected in the previous analysis, and the object detected in the current analysis partially overlaps in this area in each of the XY directions. In the case, they are recognized as the same object. In the unlikely event that multiple objects detected in the previous analysis overlap the objects detected in the current analysis, they may be combined with an object closer to the object detected in the current analysis or may have been detected from a previous analysis. The object to be synthesized may be preferentially synthesized, or the partner object to be synthesized may be determined based on some condition.

  By the way, the detection of the object in the scanning range E by the analysis of the measurement data D is performed using the measurement data D for one frame in the scanning range E as described above. Therefore, the upper end or lower end of the vertical scanning range where the scanning light L1 finishes scanning in the forward path or the backward path on all the scanning lines of the scanning range E is defined as a segment from which the measurement data D for one frame of the scanning range E is obtained. It is conceivable to perform object detection.

  However, in the vicinity of the oscillating end of the galvanometer mirror 12 where the scanning line scanned by the scanning light L1 reaches the upper end or the lower end of the vertical scanning range, an unstable operation occurs due to servo control of the oscillating motor 12a. May occur. Due to this unstable operation, there is a possibility of erroneous detection when the swing end of the galvano mirror 12 or the upper end or lower end in the vertical scanning range of the scanning light L1 is detected by a sensor or the like. When such erroneous detection occurs, the measurement data D for one frame in the scanning range E can be accurately acquired, and the object existing in the scanning range E cannot be detected correctly.

  In view of this, in the image processing unit 61 of the control device 6 of the present embodiment, the scanning light L <b> 1 scans a smaller number of scanning lines than the number of scanning lines existing in the scanning range E (in this embodiment, 50 for both the forward and backward paths). Each time it scans, it exists in the scanning range E based on the reflected light L2 of the scanning light L1 scanned on the latest 50 scanning lines (for one frame) including the scanning line last scanned by the scanning light L1. The object to be detected is detected.

  Specifically, the image processing unit 61 sends the measurement data D obtained from the scanning light L1 and the reflected light L2 for one scanning line of the forward path or the return path from the signal processing unit 3 or the measurement data D having a data amount close thereto. Each time the control device 6 receives a single packet communication, the latest measurement data D relating to the scanning line for one frame of the scanning range E stored in the measurement data storage area 64a of the RAM 64, including the measurement data D, is obtained. Using this, an object existing in the scanning range E is detected.

  If the data amount of the measurement data D received by the control device 6 from the signal processing unit 3 by one packet communication does not match the data amount of the measurement data D for one scanning line, one packet is sent. In some cases, the latest measurement data D received by communication is stored at an address location straddling the two scanning lines in the measurement data storage area 64a or only at a partial address location of one scanning line.

  In such a case, 1 of the scanning range E stored in the measurement data storage area 64a of the RAM 64 including the scanning line in which the latest measurement data D is stored at the address location corresponding to the end of the scanning line in the horizontal scanning direction. An object existing in the scanning range E is detected using the latest measurement data D relating to the scanning lines for the frames.

  Next, processing relating to the detection of the object in the scanning range E performed by the control device 6 and the determination of the stationary or moving state of the detected object will be described with reference to the flowchart of FIG.

  First, the control device 6 confirms whether or not the control device 6 has received the measurement data D from the signal processing unit 3 by packet communication (step S11). If not received (NO in step S11), step S11 is repeated. If received (YES in step S11), the received measurement data D is stored in the address portion of the measurement data storage area 64a corresponding to the scanning line and the points P0 to Pn indicated by the address information of the measurement data D. (Step S12).

  Next, the control device 6 detects an object existing on the scanning line indicated by the address information of the measurement data D received in step S11 (step S13). This object detection is performed by causing the image processing unit 61 to perform the processing described with reference to FIGS. 5 to 7 on the measurement data D received in step S11. Further, at the time of this object detection, the image processing unit 61 also makes a determination of a difference from an object that has already been detected to be present on the scanning line indicated by the address information of the previously received measurement data D. Then, the control device 6 stores the object position and size data detected by the image processing unit 61 in the analysis result storage area 64b as the latest object detection data (step S14). At the same time, the oldest object detection data in the analysis result storage area 64b is deleted. Further, the control device 6 compares the latest object detection data for one frame stored in the analysis result storage area 64b with the object detection data for one frame immediately before, thereby detecting the stationary or moving state of the detected object. Is determined by the image processing unit 61 (step S15).

  Then, the control device 6 outputs the detection result of the object by the image processing unit 61 and the determination result of the stationary or moving state to the output device 7 (step S16). The series of processes is completed as described above, and thereafter, the control device 6 repeatedly executes the processes in steps S11 to S16 described above.

  As is clear from the above description, in the object detection apparatus of this embodiment, step S13 in the flowchart of FIG. 8 is processing corresponding to the control means in the claims. Further, in the object detection device of the present embodiment, the image processing unit 61 of the control device 6 corresponds to the object detection means in the claims.

  Incidentally, when the laser radar head 5 of the object detection apparatus having the above-described configuration is installed on the column B in the vicinity of the railroad crossing A as shown in FIG. 2, as shown in the plan view of FIG. 9, the scanning range E of the scanning light L1. Will cover the entire area where vehicles and passersby (not shown) of the crossing A enter. In the object detection apparatus of the present embodiment, the presence of an obstacle is monitored by the scanning light L1 (reflected light L2) in the scanning range E of the scanning light L1 in an area where a vehicle or a passerby is not shown. Monitoring area F to be used. Therefore, the control device 6 actually detects the obstacle present in the monitoring area F and determines the stationary or moving state of the obstacle by executing the processing according to the flowchart of FIG. 8 described above. It will be.

  In addition, the monitoring area | region F mentioned above is an area | region in the orthogonal coordinate system which makes the plane along a track surface the XY coordinate plane. On the other hand, the position of the object measured by the reflected light L2 of the scanning light L1 is a position in the polar coordinate system of the space including the scanning range E of the scanning light L1 with the laser radar head 5 as the origin. Therefore, the image processing unit 61 of the control device 6 described above converts the position of the object detected from the analysis result of the measurement data D from the position on the polar coordinate system with the laser radar head 5 as the origin to the orthogonal coordinates including the monitoring region F. Convert to a position on the system. Thereby, the position and height of the obstacle in the monitoring area F are detected from the measurement data D generated based on the reflected light L2 of the scanning light L1, and the stationary or moving state of the obstacle is determined. it can.

  In the object detection device of the present embodiment having the above-described configuration, the control device 6 receives the measurement data D generated by the signal processing unit 3 by packet communication, and the measurement data D is associated with the measurement data storage area 64a. Each time it is stored in the address location, the object detection data stored in the analysis result storage area 64b is used to detect an obstacle existing in the monitoring area F (detection of an object existing in the scanning range E). However, this detection requires measurement data D for each scanning line. Therefore, at the stage after the latest measurement data D is stored in the measurement data storage area 64a, the measurement data D of the scanning line for which the measurement data D has not been stored up to the last address location in the horizontal scanning direction is monitored. Not used for area F obstacle detection.

  In addition, when the data amount of the measurement data D received by the control device 6 from the signal processing unit 3 by one packet communication matches the data amount of the measurement data D for one scanning line, the measurement data D is Each time it is received, the measurement data D of each scanning line in the measurement data storage area 64a is sequentially updated to the latest data one by one. For this reason, the image processing unit 61 of the control device 6 detects an obstacle existing in the monitoring area F (an object existing in the scanning range E) every time the latest measurement data D is received in units of scanning lines. It will be.

  Therefore, the oscillating end of the galvanometer mirror 12 or the upper or lower end of the scanning light L1 in the vertical scanning range is detected by a sensor or the like, and the detection timing is the latest measurement data D relating to the scanning line for one frame in the scanning range E. Does not need to be used as a separator input from the signal processing unit 3. Therefore, from the latest measurement data D on the scanning line for one frame in the scanning range E without considering the possibility of erroneous detection of the swing end of the galvanometer mirror 12 or the upper end or the lower end in the vertical scanning range of the scanning light L1. The detected object data can be accurately used to correctly detect an obstacle existing in the monitoring area F (an object existing in the scanning range E).

  The configuration for carrying out the object detection method of the present invention is not limited to the configuration of the object detection device described in the present embodiment. For example, measurement data D received by the control device 6 and object data detected using the measurement data D are not necessarily stored in a memory having a configuration such as the measurement data storage area 64a or the analysis result storage area 64b of the RAM 64. May be. Furthermore, the detection procedure of the obstacle (the object existing in the scanning range E) existing in the monitoring area F is not limited to the procedure shown in the flowchart of FIG.

  For example, in the present embodiment, the period in which the image processing unit 61 of the control device 6 detects an obstacle present in the monitoring region F (an object existing in the scanning range E) is used as the measurement data D from the signal processing unit 3. Each time it is received by packet communication (every time the measurement data D of each scanning line in the measurement data storage area 64a is sequentially updated to the latest data one by one).

  However, every time the measurement data D from the signal processing unit 3 is received a predetermined number of times of packet communication (every time a predetermined number of measurement data D of each scanning line in the measurement data storage area 64a is updated to the latest data). ), The image processing unit 61 of the control device 6 detects the objects existing on the scanning lines from the measurement data D corresponding to the predetermined number of received scanning lines, and further, the object for the latest one frame. You may comprise so that the detection (object which exists in the scanning range E) which exists in the monitoring area | region F may be detected using detection data.

  With this configuration, the same effect as that of the object detection device of the present embodiment can be obtained, and the frequency of detecting obstacles (objects existing in the scanning range E) existing in the monitoring region F is reduced. It is also possible to obtain an effect of reducing the processing burden. On the other hand, if the configuration of the object detection device of the present embodiment is adopted, the obstacle (object) is stationary or moved as the obstacle (object present in the scanning range E) in the monitoring area F is detected more frequently. The state can be determined with high resolution.

  In any case, the period for detecting the obstacle present in the monitoring region F (the object present in the scanning range E) is not limited to the above-described period, but the timing at which the galvano mirror 12 reaches the swing end (scanning light) As long as L1 is irrelevant to the timing at which the scanning line at the upper end or the lower end in the vertical scanning range is finished, an arbitrary cycle can be used.

  Further, in the present embodiment, the laser radar head 5 is installed on the column B near the railroad crossing A to check for the presence of obstacles in the monitoring area F through which the vehicle C and passersby (not shown) of the railroad crossing A can pass. The case of detection has been described. However, the present invention is not limited to the railroad crossing A, and can be widely applied to the case where various monitoring areas where the presence of an object needs to be monitored are monitored by reflected light of scanning light.

DESCRIPTION OF SYMBOLS 1 Light projection part 1a Laser diode 1b Light projection lens 1c LD driver 2 Light reception part 2a Light reception lens 2b Light reception part main body 3 Signal processing part 5 Laser radar head 6 Control apparatus 7 Output device 11 Polygon mirror 11a Motor 11b Motor driver 12 Galvano mirror 12a Motor 12b Motor driver 31 Main signal processing unit 32 Time measurement unit 61 Image processing unit 62 Fault diagnosis unit 63 Error correction unit 64 RAM
64a Measurement data storage area 64b Analysis result storage area A Railroad crossing B Post C Vehicle D Measurement data E Scanning range F Monitoring area L Laser light L1 Scanning light L2 Reflected light P0 to Pn Point Sc Projection condition signal Sd Required time signal Sh Control condition Sm Control signal Sq Light reception intensity signal Sr Light reception signal Ss Light emission synchronization signal St Trigger signal W Light emission window

Claims (4)

In a method of scanning an entire monitoring area with scanning light that sequentially scans a plurality of scanning lines, and detecting an object existing in the monitoring area by reflected light of each scanning light,
Each time the scanning light scans a predetermined number of scanning lines different from the number of scanning lines located on the monitoring area, it exists in the monitoring area based on the reflected light of the latest scanning light of each scanning line. Detect objects to
An object detection method characterized by the above.   The object detection method according to claim 1, wherein the predetermined number is one. A laser radar that scans the entire monitoring area with scanning light that sequentially scans a plurality of scanning lines;
Object detection means for detecting an object present in the monitoring area based on the reflected light of each scanning light scanned on each scanning line located on the monitoring area;
Reflected light data storage means for storing the latest reflected light data of the scanning light respectively scanned on the scanning lines located on the monitoring area;
Each time the scanning light scans a predetermined number of scanning lines different from the number of scanning lines located on the monitoring area, each of the latest scanning lines stored on the reflected light data storage means is scanned. Control means for detecting an object present in the monitoring area by the object detection means based on data of reflected light of the scanning light;
An object detection apparatus comprising:   The object detection apparatus according to claim 3, wherein the predetermined number is one.

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