JP5978565B2 - Monitoring device and monitoring method - Google Patents

Description

  The present invention relates to a monitoring apparatus and a monitoring method.

  A distance measuring technique for measuring a distance using a laser is known. Such distance measurement technology not only measures the distance to the object, but also detects obstacles around the vehicle, detects obstacles caught between platform doors installed between the railway platform and the train, It is applied to various monitoring technologies such as detecting the flow of people in rooms and halls.

  As an example of such a monitoring technique, there is an automatic door safety device provided below a door of a platform movable safety fence that prevents a passenger from falling on a track on a platform of a station or the like. This safety device for automatic doors irradiates laser light in a substantially vertical direction near the door portion, and performs surface detection in a detection area parallel to the door portion. At this time, when there is an obstacle in the fan-shaped area, the automatic door safety device generates a distance image including distance information to the obstacle, and based on the generated distance image, there is an obstacle in the fan-shaped area. Determine if it exists. Thus, the automatic door safety device aims to reduce the number of blind spots when detecting obstacles caught in the door portion and accurately determine the presence or absence of obstacles.

JP 2009-294053 A

  However, in the above-described conventional technology, there is a problem that power consumption increases as the spatial resolution is improved as information on a moving object is acquired in more detail. For example, in the case of the above automatic door safety device, when acquiring detailed information on the moving body in the sector area, the light emitting unit that emits laser light when scanning laser light at a predetermined angle is used. It is necessary to increase the number of pulses to be supplied. As described above, when the number of pulses is increased, even if the spatial resolution in the sector area is improved, the power consumption increases as the number of pulses increases.

  The disclosed technology has been made in view of the above, and an object thereof is to provide a monitoring device and a monitoring method capable of acquiring detailed information of a moving body while suppressing an increase in power consumption.

  The monitoring device disclosed in the present application includes a light source that generates laser light. Furthermore, the monitoring device has a scanning unit that scans the laser light emitted by the light source in a predetermined scanning range. Furthermore, the monitoring device includes a detection unit that detects the object using reflected light of a laser beam reflected by the object existing within the scanning range. Furthermore, when the object is detected by the detection unit, the monitoring device detects a laser beam included outside a predetermined range based on an irradiation point of the laser beam in which the object is detected in the scanning range. A light emission control unit that causes the light source to emit light so that the number of irradiation points becomes the first number of irradiation points. Further, the issuance control unit is configured to provide a second irradiation in which the number of irradiation points within a predetermined range with respect to the irradiation point of the laser beam where the object is detected in the scanning range is larger than the first irradiation point number. The light source is caused to emit light so as to achieve a score.

  According to one aspect of the monitoring device disclosed in the present application, there is an effect that detailed information of the moving body can be acquired while suppressing an increase in power consumption.

FIG. 1 is a block diagram illustrating a functional configuration of the monitoring apparatus according to the first embodiment. FIG. 2 is a diagram illustrating an example of an irradiation point irradiated with laser light when a moving body is not detected. FIG. 3 is a diagram illustrating an example of an irradiation point irradiated with laser light when a moving body is detected. FIG. 4 is a diagram illustrating an example of the input distance distribution. FIG. 5 is a diagram illustrating an example of the reference distance distribution. FIG. 6 is a diagram illustrating an example of a comparison result between the reference distance distribution and the input distance distribution. FIG. 7 is a diagram illustrating an example of a timing table when low-resolution sampling is executed. FIG. 8 is a diagram illustrating an example of a timing table when high-resolution sampling is executed. FIG. 9 is a flowchart illustrating the procedure of the monitoring process according to the first embodiment. FIG. 10 is a diagram illustrating an application example 1 of an irradiation point irradiated with a laser beam when a moving body is detected. FIG. 11 is a diagram illustrating an application example 2 of an irradiation point to which a laser beam is irradiated when a moving body is detected. FIG. 12 is a diagram illustrating an application example 3 of an irradiation point to which a laser beam is irradiated when a moving body is detected. FIG. 13 is a diagram illustrating an application example of the comparison result of the reference distance distribution and the input distance distribution. FIG. 14 is a diagram illustrating an application example of the timing table when high-resolution sampling is executed. FIG. 15 is a diagram illustrating the correlation between the angle formed by the moving direction of the monitoring device and the irradiation direction of the laser beam and the speed of the monitoring device. FIG. 16 is a diagram illustrating an example of the input distance distribution. FIG. 17 is a diagram illustrating an example of the reference distance distribution. FIG. 18 is a diagram illustrating an example of the movement distance distribution. FIG. 19 is a diagram illustrating an example of a comparison result of the reference distance distribution, the input distance distribution, and the movement distance distribution.

  Hereinafter, embodiments of a monitoring device and a monitoring method disclosed in the present application will be described in detail with reference to the drawings. Note that this embodiment does not limit the disclosed technology. Each embodiment can be appropriately combined within a range in which processing contents are not contradictory.

[Configuration of monitoring device]
First, the functional configuration of the monitoring apparatus according to the present embodiment will be described. FIG. 1 is a block diagram illustrating a functional configuration of the monitoring apparatus according to the first embodiment. The monitoring apparatus 10 shown in FIG. 1 detects a moving body existing within the scanning range of its own apparatus using a laser. In the example of FIG. 1, the following description is given on the assumption that the monitoring device 10 is stationary without moving.

  As shown in FIG. 1, the monitoring device 10 includes a light source LD (Laser Diode) 11, an LD driving unit 12, a scanning unit 13, a light receiving unit 14, a distance storage unit 15a, a detection unit 15, and a timing storage. And a light emission control unit 16. Note that the monitoring apparatus 10 controls communication with cameras and other devices, including various functional units included in known computers other than the functional units illustrated in FIG. 1, such as various input devices and audio output devices. It is good also as having functional parts, such as a communication interface.

  Among these, the light source LD11 is a light source that generates a pulsed light beam, so-called laser light. As one aspect of the light source LD11, a semiconductor laser diode or the like can be given. The laser light emitted by the light source LD11 is introduced into the scanning unit 13 described later after being adjusted to parallel light via an optical system (not shown).

  The LD driving unit 12 is a circuit that causes the light source LD11 to emit light by applying a voltage to the light source LD11. As one aspect, the LD drive unit 12 causes the light source LD11 to emit pulses in accordance with an instruction from the light emission control unit 16 described later.

  The scanning unit 13 is a mechanism unit that scans the laser light emitted from the light source LD11 in a predetermined scanning range. One aspect of the scanning unit 13 includes an optical deflection element formed from an electro-optic material that can change the refractive index by applying a voltage. As an example, the scanning unit 13 uses a two-dimensional scanning mechanism (not shown) to deflect the laser light introduced from the light source LD11 in the horizontal direction or the vertical direction, thereby performing laser on the horizontal scanning line set in the scanning range. Scan light alternately left and right. Here, the case where the scanning unit 13 performs the raster scan is illustrated, but other scanning methods can be applied.

  Here, the monitoring apparatus 10 according to the present embodiment detects the moving body using the reflected light of the laser light reflected by the object existing within the scanning range for scanning the laser light irradiated by the light source LD11. At this time, when the monitoring apparatus 10 according to the present embodiment detects the moving body, the laser light included outside the predetermined range based on the irradiation point of the laser beam in which the moving body is detected in the scanning range. The light source LD11 is caused to emit light so that the number of irradiation points becomes the first number of irradiation points. Furthermore, the monitoring apparatus 10 according to the present embodiment has a number of irradiation points within a predetermined range with reference to the irradiation point of the laser beam in which the moving body is detected in the scanning range, which is larger than the first irradiation point number. The light source LD11 is caused to emit light so that the number of irradiation points is 2.

  The light emission control of the light source LD11 will be described with reference to FIGS. FIG. 2 is a diagram illustrating an example of an irradiation point irradiated with laser light when a moving body is not detected. FIG. 3 is a diagram illustrating an example of an irradiation point irradiated with laser light when a moving body is detected.

  In the example of FIGS. 2 and 3, four points (X1, Y1), (X11, Y1), (X1, Y11), and (X11, Y11) are included in a two-dimensional coordinate system whose scanning range includes the X coordinate and the Y coordinate. Is assumed to be a rectangular region formed by 2 and 3, the maximum sampling frequency of the monitoring apparatus 10 is a period during which the coordinate unit interval, for example, the coordinates (X1, Y1) to the coordinates (X2, Y1) are scanned. . In the examples of FIGS. 2 and 3, “black circles” in the drawings indicate laser light irradiation points, and “white circles” in the drawings are not actually irradiated but can be irradiated. Indicates a point. The scanning range and the sampling frequency are not limited to the above-described example, and a scanning range having an arbitrary shape or size and a sampling frequency having an arbitrary interval can be adopted.

  As shown in FIGS. 2 and 3, the monitoring apparatus 10 performs a raster scan of the laser light with the coordinates (X1, Y1) as the start point and the coordinates (X11, Y11) as the end point. That is, the monitoring apparatus 10 scans the first scanning line from the coordinates (X1, Y1) to the coordinates (X11, Y1) in the right direction. The monitoring apparatus 10 moves in the vertical direction from the coordinates (X11, Y1) to the coordinates (X11, Y2), and then moves the second scanning line from the coordinates (X11, Y2) to the coordinates (X1, Y2) to the left. Return to scan. In this way, the scanning of the horizontal scanning line is repeatedly executed until the end point coordinates (X11, Y11) arrive. In the following description, a scanning line scanned in the right direction may be referred to as “outward path”, and a scanning line scanned in the left direction may be referred to as “return path”.

  When the moving body is not detected under such an environment in which scanning is executed, as shown in FIG. 2, coordinates indicated by black circles, for example, (X1, Y1), (X3, Y1), Laser light is irradiated to (X5, Y1) or the like. That is, in the forward scanning line, when the interval at which the laser beam is irradiated at the maximum sampling frequency is set to one sampling interval, the laser beam is emitted every other sampling interval. On the other hand, the laser beam is not irradiated on the scanning line in the return path.

  In addition, when a moving body is detected, as shown in FIG. 3, an existence range in which the moving body is estimated to exist in the future based on the irradiation point (X7, Y7) where the moving body is detected, In this example, laser light is also applied to coordinates (shaded portions in the drawing) within two sampling intervals that are vertically and horizontally oblique. In this case, a part of the scanning line on the return path, that is, a part of the sixth scanning line and the eighth scanning line is also irradiated with the laser light, and the maximum part of the fifth scanning line to the ninth scanning line. Laser light is irradiated at a sampling frequency of. In addition, the presence range of a moving body is not limited to said example, Arbitrary shapes and arbitrary magnitude | sizes can be set. For example, a larger existence range can be set as the moving speed of the moving body increases.

  Thus, when the moving body is not detected, the number of irradiation points when the laser beam is irradiated at the maximum sampling frequency is “121”, whereas the number of irradiation points is reduced by “85”. Can be "36". When a moving body is detected, the number of irradiation points increases by “16” from the number of irradiation points “36” when the moving body is not detected, but the laser beam is irradiated at the maximum sampling frequency. Compared to the case, the number of irradiation points is less than half. In the following, sampling in which the distance is measured by irradiating laser light when the moving body is not detected may be referred to as “low-resolution sampling”. In the following, sampling in which a distance is measured by irradiating a laser beam when a moving body is detected may be referred to as “high resolution sampling”.

  Furthermore, when a moving body is detected, the spatial resolution of the moving body and the surroundings of the moving body can be improved by intensively irradiating the existing range of the moving body with laser light. Information can also be obtained.

  Therefore, according to the monitoring apparatus 10 according to the present embodiment, it is possible to improve the spatial resolution of the moving body and the periphery of the moving body by minimizing the number of laser light irradiation points, thereby suppressing an increase in power consumption. Meanwhile, it is possible to acquire detailed information of the moving body.

  Returning to the description of FIG. 1, the light receiving unit 14 is a mechanism unit that receives the reflected light of the laser beam. As one aspect, the reflected light of the laser beam reflected by the object existing within the scanning range is introduced into a light receiving element (not shown) through a light receiving lens (not shown). When the reflected light is introduced into the light receiving element in this way, the light receiving unit 14 notifies the detection unit 15 described later that the reflected light of the laser beam has been received.

  The distance memory | storage part 15a is a memory | storage part which memorize | stores the distance from the own apparatus to the object which reflected the laser beam. As an example, the distance storage unit 15a is read by the detection unit 15 described later in order to detect the presence or absence of a moving body. As another example, the distance storage unit 15a smoothes the distance measured during the previous scan and the distance measured during the current scan in order to follow changes in the surrounding environment of the monitoring device 10. It is updated by the detection unit 15 described later.

  As one aspect of the distance storage unit 15a, data in which the distance from the own apparatus measured at the irradiation point to the object reflecting the laser light is associated with each irradiation point of the laser light can be employed. Hereinafter, the distance of each irradiation point distributed in the scanning range and referred to by the detection unit 15 described later when detecting the moving body may be referred to as “reference distance distribution”. In the following description, the distance between the irradiation points distributed in the scanning range and the distance actually measured by the detection unit 15 described later may be referred to as “input distance distribution”.

  The detection unit 15 is a processing unit that detects a moving object with reference to the distance storage unit 15a. As one aspect, the detection unit 15 has a time difference between the time when the laser light is irradiated by the light source LD11 and the time when the reflected light is received by the light receiving unit 14 each time the laser light is irradiated by the light source LD11. Measure the distance from your device to the object that reflected the laser beam. And the detection part 15 samples an input distance distribution by repeatedly performing distance measurement for all the irradiation points in the scanning range. Thereafter, the detection unit 15 compares the reference distance distribution stored in the distance storage unit 15a with the input distance distribution sampled this time. That is, the detection unit 15 performs a calculation for subtracting the distance included in the reference distance distribution from the distance included in the input distance distribution between the irradiation points. In addition, although the case where the distance included in the reference distance distribution is subtracted from the distance included in the input distance distribution is illustrated here, the distance included in the input distance distribution may be subtracted from the distance included in the reference distance distribution. Good.

  At this time, when the subtraction value subtracted between the irradiation points is a “positive” value, it can be estimated that the distance to the object is farther than before. On the other hand, when the subtraction value subtracted between the irradiation points is a “negative” value, it can be estimated that the distance to the object is closer than before. Further, when the subtraction value subtracted between the irradiation points is “zero”, it can be estimated that the distance to the object is the same as before. Thus, when the subtraction value subtracted between each irradiation point takes a value other than zero, it can be considered that a moving body exists in the said irradiation point. In the following, a case where only an object approaching the own device is detected as a moving body is illustrated, but only an object moving away from the own device is detected as a moving body, or an object approaching and moving away from the own device. Both of them can also be detected as moving objects.

  Here, the detection method of a moving body is demonstrated using FIGS. FIG. 4 is a diagram illustrating an example of the input distance distribution. FIG. 5 is a diagram illustrating an example of the reference distance distribution. FIG. 6 is a diagram illustrating an example of a comparison result between the input distance distribution and the reference distance distribution. These examples of FIGS. 4, 5 and 6 show the case where the distance is measured by the low resolution sampling described with reference to FIG. In the example of FIG. 6, the irradiation point where the moving body is detected is highlighted.

  When the input distance distribution shown in FIG. 4 is sampled, calculation for subtracting the distance included in the reference distance distribution shown in FIG. 5 from the distance included in the input distance distribution shown in FIG. Executed. When subtraction is executed between all irradiation points in this way, a comparison result between the input distance distribution and the reference distance distribution shown in FIG. 6 is obtained. For example, in the example of the irradiation point (X7, Y7), the distance “2” of the irradiation point (X7, Y7) included in the input distance distribution to the distance “2” of the irradiation point (X7, Y7) included in the reference distance distribution. Subtraction value “−1” is obtained by subtracting 3 ”. Thus, when the “negative” subtraction value is calculated, the detection unit 15 detects that a moving body is present at the irradiation point (X7, Y7).

  As described above, information on a moving object obtained by low resolution sampling or high resolution sampling can be output to an arbitrary output destination. For example, the data can be output to an external device (not shown) such as an external device connected via a network, a storage device (not shown) such as a USB memory, a recording medium (not shown) such as a CD-ROM. Moreover, when outputting the information of a moving body, it can process and output to arbitrary forms. For example, the distance image may be generated by expressing the subtraction value of the input distance distribution and the illumination distance distribution as a gray value, and the speed and acceleration of the moving object are calculated from the subtraction value of the input distance distribution and the illumination distance distribution. It is good as well.

  Returning to the description of FIG. 1, the timing storage unit 16 a is a storage unit that stores the timing at which the light source LD 11 emits light in the process of scanning the laser beam. As an example, the timing storage unit 16 a is read by the light emission control unit 16 described later when the scanning unit 13 starts scanning with laser light. As another example, the timing storage unit 16a is updated by a light emission control unit 16 to be described later when switching between the low resolution sampling mode and the high resolution sampling mode. As an aspect of the timing storage unit 16a, a timing table in which a light emission time for causing the light source LD11 to emit light for each coordinate included in the scanning range can be employed.

  The light emission control unit 16 is a processing unit that performs light emission control of the light source LD11 using the timing storage unit 16a. As one aspect, the light emission control unit 16 changes the length of the light emission interval of the light source LD11 or changes the ratio of the scanning lines to be emitted to the light source LD11 among the scanning lines included in the scanning range. Increase or decrease the number.

  Explaining this, the light emission control unit 16 calculates the existence range of the moving object from the irradiation point where the moving object is detected when the moving object is detected by the detection unit 15 during the execution of the low resolution sampling. And the light emission control part 16 performs the update which adds the coordinate corresponding to the presence range of a moving body among the coordinates memorize | stored in the timing memory | storage part 16a to an irradiation point. Thereafter, when the scanning of the laser beam by the scanning unit 13 is started, the light emission control unit 16 emits light at the coordinates set as the irradiation point among the light emission times stored in the timing storage unit 16a after the addition of the irradiation point. The light source LD11 is caused to emit light through the LD driving unit 12. Thereby, high resolution sampling is performed.

  Further, the light emission control unit 16 has been added to the moving object existence range among the coordinates stored in the timing storage unit 16a when the moving unit is not detected by the detecting unit 15 during the execution of the high resolution sampling. Update to reset the irradiation point. Thereafter, when the scanning of the laser light by the scanning unit 13 is started, the light emission control unit 16 emits light at the coordinates set as the irradiation point among the light emission times stored in the timing storage unit 16a after the irradiation point reset. The light source LD11 is caused to emit light through the LD driving unit 12. Thereby, low resolution sampling is performed.

  Here, an updating method of the timing storage unit 16a will be described with reference to FIGS. FIG. 7 is a diagram illustrating an example of a timing table when low-resolution sampling is executed. FIG. 8 is a diagram illustrating an example of a timing table when high-resolution sampling is executed. In the examples of FIGS. 7 and 8, coordinates set as irradiation points are displayed in reverse video. In the example of FIG. 8, a moving body is detected at the irradiation point (X7, Y7) and an irradiation point is added to the existence range of the moving body.

  As shown in FIG. 7, when low resolution sampling is executed, the following light emission control is executed by the light emission control unit 16. That is, in the forward path of the first scanning line, the light source LD11 emits light at the timing of T (1,1), T (3,1)... T (11,1), and the backward path of the second scanning line does not emit light. In the third scanning line, the light source LD11 emits light at the timing of T (1,3)... T (11,3). Then, when a moving body is detected at the irradiation point (X7, Y7), as shown in FIG. 8, the existence range of the moving body, that is, coordinates of two sampling intervals that are vertically and horizontally oblique at the irradiation point (X7, Y7). Update is performed to add 16 to the irradiation points. After that, when high resolution sampling is executed, the same light emission control as that of low resolution sampling is executed until the return path of the fourth scanning line, but the fifth scanning line to the ninth scanning line are not emitted during low resolution sampling. The light source LD11 also emits light at the irradiation point. That is, the light source LD11 is turned on at a timing of T (5,6) to T (9,6) or T (5,8) to T (9,8) even in a part of the return path of the sixth scanning line and the eighth scanning line. Make it emit light. Furthermore, the light source LD11 is caused to emit light at the maximum sampling frequency at some timings of the fifth to ninth scanning lines.

  Moreover, the light emission control part 16 changes the light quantity which light source LD11 light-emits between the range which makes the number of irradiation points the 1st irradiation point number, and the existence range which makes the number of irradiation points the 2nd irradiation point number. You can also. That is, when sampling is performed by increasing the spatial resolution of the existence range of the moving object, the amount of laser light irradiation per unit area increases. For this reason, power consumption increases, and there is a possibility of affecting the human body, particularly the “eye”. Further, the amount of light that returns to the light receiving unit 14 among the irradiated laser light decreases in proportion to the square of the distance.

  Therefore, when the detection unit 15 detects a moving body, the light emission control unit 16 increases the spatial resolution of the moving object's existence range and decreases the irradiation amount of one pulse in the light source LD11. As a result, an increase in power consumption can be suppressed, and the influence on the human body, particularly the “eye” can also be suppressed. When the moving body moves away, the irradiation amount of one pulse in the light source LD11 can be increased.

  For example, in the example shown in FIG. 2 and FIG. 3, when executing high resolution sampling, the number of irradiation points in the moving object existing range is 25, whereas low resolution sampling is executed. In this case, the number of irradiation points in a range common to the range where the moving object exists is nine. At this time, if what is performed at “(10 WX × 20 ns) / pulse” at the time of low resolution sampling is performed at “(3.6 WX × 20 ns) / pulse at the time of high resolution sampling, the power consumption by the light source LD 11 will not change. , Increase in power consumption can be suppressed.

  Note that various integrated circuits and electronic circuits can be employed for the detection unit 15 and the light emission control unit 16. For example, an ASIC (Application Specific Integrated Circuit) is an example of the integrated circuit. Examples of the electronic circuit include a central processing unit (CPU) and a micro processing unit (MPU).

  In addition, a semiconductor memory element or a storage device can be adopted as a storage unit such as the distance storage unit 15a and the timing storage unit 16a. For example, examples of the semiconductor memory element include a video random access memory (VRAM), a random access memory (RAM), a read only memory (ROM), and a flash memory. Examples of the storage device include storage devices such as a hard disk and an optical disk.

[Process flow]
Next, the process flow of the monitoring apparatus according to the present embodiment will be described. FIG. 9 is a flowchart illustrating the procedure of the monitoring process according to the first embodiment. This monitoring process is a process that is repeatedly executed when the power of the monitoring apparatus 10 is ON.

  As shown in FIG. 9, the monitoring device 10 starts scanning the laser beam, and refers to the timing storage unit 16a to which the irradiation point corresponding to the moving object existence range is not added to the emission time of each irradiation point. The light source LD11 is caused to emit light, and low resolution sampling is executed (step S101).

  Subsequently, the monitoring apparatus 10 determines whether or not the moving body is present in the scanning range by comparing the reference distance distribution stored in the distance storage unit 15a and the input distance distribution sampled this time (step) S102). When there is no moving object (No at Step S102), the process at Step S101 is repeatedly executed.

  At this time, when the moving body exists (Yes at Step S102), the monitoring apparatus 10 calculates an existing range in which the moving body is estimated to be present in the future based on the irradiation point where the moving body is detected. (Step S103).

  And the monitoring apparatus 10 performs the update which adds the coordinate corresponding to the presence range of a moving body among the coordinates memorize | stored in the timing memory | storage part 16a to an irradiation point (step S104). Thereafter, the monitoring device 10 starts scanning with laser light, and refers to the timing storage unit 16a after the addition of the irradiation point, and causes the light source LD11 to emit light during the light emission time of each irradiation point, thereby executing high-resolution sampling ( Step S105).

  Subsequently, the monitoring apparatus 10 determines whether or not the moving body is present in the scanning range by comparing the reference distance distribution stored in the distance storage unit 15a and the input distance distribution sampled this time (step) S106).

  At this time, if there is a moving body (No at Step S106), the monitoring apparatus 10 repeatedly executes the processes at Steps S103 to S105 described above.

  On the other hand, when the moving body does not exist (Yes at Step S106), the monitoring apparatus 10 performs an update to reset the irradiation point added to the moving body existing range among the coordinates stored in the timing storage unit 16a. (Step S107), the process returns to Step S101. Note that the monitoring device 10 repeatedly executes the processes in steps S101 to S107 as long as the power supply of the own device is ON.

[Effect of Example 1]
As described above, according to the monitoring device 10 according to the present embodiment, it is possible to improve the spatial resolution around the moving body and the moving body by minimizing the number of laser light irradiation points. It is possible to acquire detailed information of the moving object while suppressing the increase.

  In addition, the monitoring apparatus 10 according to the present embodiment changes the length of the light emission interval of the light source LD11 or changes the ratio of the scanning lines that the light source LD11 emits among the scanning lines included in the scanning range. Increase or decrease the number of. For this reason, in the monitoring apparatus 10 which concerns on a present Example, it is possible to increase the number of the irradiation points contained in the presence range of a moving body among scanning ranges multifacetedly.

  Furthermore, the monitoring apparatus 10 according to the present embodiment includes a range in which the number of irradiation points is the first number of irradiation points and a range in which the number of irradiation points is the second number of irradiation points when the moving body is detected. The amount of light to be emitted to the light source LD11 is changed. For example, when a moving body is detected, it is possible to increase the spatial resolution of the moving object's existence range and to reduce the irradiation amount of one pulse in the light source LD11. Thereby, in the monitoring apparatus 10 according to the present embodiment, it is possible to suppress an increase in power consumption and to suppress an influence on the human body, particularly the “eye”.

  Although the embodiments related to the disclosed apparatus have been described above, the present invention may be implemented in various different forms other than the above-described embodiments. Therefore, another embodiment included in the present invention will be described below.

[Application example 1 of irradiation point]
In the first embodiment, the case where the light source LD11 emits light with all the coordinates included in the existence range of the moving body as the irradiation point is illustrated. There is no need to emit light.

  For example, in the disclosed apparatus, the coordinates of the horizontal position similar to the irradiation point on the forward scanning line of the low-resolution sampling are the coordinates on the backward scanning line among the coordinates included in the moving object existence range. The light source LD11 can also emit light as an irradiation point. This makes it possible to acquire detailed information on the moving object while suppressing an increase in power consumption without changing the sampling frequency.

  FIG. 10 is a diagram illustrating an application example 1 of an irradiation point irradiated with a laser beam when a moving body is detected. In the example of FIG. 10, as in the example of FIG. 3, it is assumed that the moving body is detected at the irradiation point (X7, Y7). As shown in FIG. 10, coordinates (X5, Y6), (X7, Y6), (X9, Y6), (X5, Y8), (X7, Y8), and (X9, Y8) are included in the moving object existence range. Is irradiated with a laser beam as an irradiation point. As described above, in the example shown in FIG. 10, when the maximum sampling frequency is used as a reference, the laser light is irradiated at every sampling interval in all scanning lines, so that it is not necessary to change the sampling frequency. Furthermore, in the example shown in FIG. 10, although the number of irradiation points increases by “6” from the number of irradiation points “36” when the moving body is not detected, the number of irradiation points is larger than that in the example shown in FIG. Increase of “10” is small, and increase of power consumption can be effectively suppressed.

[Application example 2 of irradiation point]
The disclosed apparatus can also cause the light source LD11 to emit light as an irradiation point by focusing on the coordinates on the forward scanning line among the coordinates included in the existence range of the moving object. As a result, it is possible to acquire detailed information of the moving object while suppressing an increase in power consumption by only partially changing the sampling frequency.

  FIG. 11 is a diagram illustrating an application example 2 of an irradiation point to which a laser beam is irradiated when a moving body is detected. In the example of FIG. 11, as in the example of FIG. 3, it is assumed that the moving body is detected at the irradiation point (X7, Y7). As shown in FIG. 11, coordinates (X6, Y5), (X8, Y5), (X6, Y7), (X8, Y7), (X6, Y9), and (X8, Y9) in the existence range of the moving object Is irradiated with a laser beam as an irradiation point. As described above, in the example shown in FIG. 11, the laser beam is irradiated as the maximum sampling frequency by limiting the existence range of the moving object. Furthermore, in the example shown in FIG. 11, although the number of irradiation points increases by “6” from the number of irradiation points “36” when the moving body is not detected, the number of irradiation points is larger than that in the example shown in FIG. Increase of “10” is small, and increase of power consumption can be effectively suppressed.

[Application example 3 of irradiation point]
In addition, the disclosed apparatus can change the sampling phase for each scanning line. As a result, the arrangement interval of the irradiation points included in the moving object's existing range can be made uniform in both the horizontal and vertical directions. Detailed body information can be obtained.

  FIG. 12 is a diagram illustrating an application example 3 of an irradiation point to which a laser beam is irradiated when a moving body is detected. In the example of FIG. 12, the case where the moving body is detected at the irradiation point (X7, Y7) is assumed as in the example of FIG. As shown in FIG. 12, the laser beam is irradiated with the coordinates (X6, Y6), (X8, Y6), (X6, Y8), and (X8, Y8) as the irradiation points in the existence range of the moving body. In this way, in the example shown in FIG. 12, the arrangement interval of the irradiation points can be made uniform in both the horizontal direction and the vertical direction only by adding four irradiation points within the existence range of the moving body shown by the hatching. Further, in the example shown in FIG. 12, although the number of irradiation points is increased by “4” from the number of irradiation points “36” when the moving body is not detected, the number of irradiation points is also compared with the example shown in FIG. Increase of “12” is small, and the increase of power consumption can be effectively suppressed.

[Number of moving objects]
In the first embodiment, the case where there is one moving body detected in the scanning range is exemplified, but it is not always necessary that one moving body is detected in the scanning range. The disclosed apparatus can also be applied when there are a plurality of detected moving bodies.

  FIG. 13 is a diagram illustrating an application example of the comparison result of the reference distance distribution and the input distance distribution. FIG. 14 is a diagram illustrating an application example of the timing table when high-resolution sampling is executed. The comparison results of the input distance distribution and the reference distance distribution shown in FIG. 13 are four points of irradiation points (X1, Y9), irradiation points (X5, Y3), irradiation points (X7, Y9), and irradiation points (X9, Y9). Indicates that a moving object has been detected. Further, since the four irradiation points all take a “negative” value, it also indicates that the moving body detected at any of the irradiation points is approaching. In this case, as shown in FIG. 14, the light source LD11 can emit light with the coordinates included in the existence range of each moving body as an irradiation point.

  In addition, the disclosed apparatus has an irradiation point on which a moving body having the highest relative speed approaching the own apparatus among a plurality of moving bodies is detected prior to other irradiation points, and is based on the irradiation point. The light source LD11 can also emit light with the coordinates included in the range as the irradiation point. For example, in the example of FIG. 13, the absolute value is the largest among the four irradiation points (X1, Y9), irradiation points (X5, Y3), irradiation points (X7, Y9), and irradiation points (X9, Y9). Only the large irradiation point (X5, Y3) is given priority, and the coordinates included in the existence range are set as the irradiation point. As a result, it is possible to prevent an increase in the proportion of irradiation points in the coordinates included in the scanning range, thereby effectively suppressing an increase in power consumption.

  In addition, although the case where the object detected by the own device moves is described here, the detection of a plurality of objects is also possible when the object is stationary and the own device or the mounting device on which the own device is mounted moves. Furthermore, priority can be given to detailed detection of objects with maximum relative speed.

[Move monitoring device]
In the first embodiment, the case where the monitoring device 10 is stationary is illustrated. However, the disclosed device is not limited to this, and the monitoring device 10 or a mounting device on which the monitoring device 10 is mounted, for example, a vehicle moves. Even if it is, it is applicable.

  FIG. 15 is a diagram illustrating the correlation between the angle formed by the moving direction of the monitoring device and the irradiation direction of the laser beam and the speed of the monitoring device. For example, as shown in FIG. 15, when the angle formed by the moving direction of the monitoring device 10 and the irradiation direction of the laser beam is “α (Xn, Yn)” and the speed of the monitoring device 10 is “V”, scanning is performed. The moving distance L after the required time t seconds is “V * T * cos α (Xn, Yn)”.

  For this reason, if the speed V of the monitoring device 10 measured by a speed sensor or the like is acquired, the moving body can be detected as in the first embodiment. That is, a shift due to movement occurs between the input distance distribution and the reference distance distribution, but the time required for scanning from the subtraction value obtained by subtracting the distance included in the reference distance distribution from the distance included in the input distance distribution between the irradiation points. By subtracting the movement distance L after t seconds, the influence of movement can be eliminated.

  Here, the detection method of a moving body is demonstrated using FIGS. FIG. 16 is a diagram illustrating an example of the input distance distribution. FIG. 17 is a diagram illustrating an example of the reference distance distribution. FIG. 18 is a diagram illustrating an example of the movement distance distribution. FIG. 19 is a diagram illustrating an example of a comparison result of the reference distance distribution, the input distance distribution, and the movement distance distribution. In the examples of FIGS. 16 to 19, the distance is measured by the low resolution sampling described with reference to FIG. 2. In the example of FIG. 19, the irradiation point where the moving body is detected is highlighted.

  When the input distance distribution illustrated in FIG. 16 is sampled, the monitoring apparatus 10 subtracts the distance included in the reference distance distribution illustrated in FIG. 17 from the distance included in the input distance distribution illustrated in FIG. When the subtraction is executed between all the irradiation points in this way, the monitoring device 10 calculates the movement distances included in the movement distance distribution shown in FIG. 18 from the subtraction values between the input distance distribution and the reference distance distribution. Subtract further between the irradiation points. In this way, a subtraction value between the input distance distribution, the reference distance distribution, and the movement distance distribution shown in FIG. 19 is obtained. In the example shown in FIG. 19, the irradiation point other than the irradiation point (Xn−2, Yn−2) is zero, but the subtraction value of the irradiation point (Xn−2, Yn−2) is “−4”. It becomes. Thus, when a “negative” subtraction value is calculated, it is detected that a moving body is present at the irradiation point (Xn−2, Yn−2).

  Thus, the monitoring converted from the change in the distance from the monitoring device 10 to the object measured for each irradiation point using the reflected light of the laser light and the speed output by the sensor for measuring the speed of the monitoring device 10. A moving body is detected based on the moving distance of the device 10. Thereby, even when the monitoring device 10 is moving, it is possible to detect the moving body.

[Horizontal surface detection, etc.]
In the first embodiment, the case where an approaching object is detected as the moving body, that is, the case where the vertical direction is detected is exemplified, but the disclosed apparatus is not limited thereto. For example, the disclosed apparatus can also be applied to a case where a falling object is detected by setting the scanning range to the top surface, that is, a case where the horizontal direction is detected.

[Monitoring target]
In the first embodiment, the case where the moving body is the monitoring target is illustrated, but it is not always necessary to set only the moving body as the monitoring target. For example, the disclosed apparatus may detect an object whose distance from the apparatus is within a predetermined distance. In this case, the disclosed apparatus calculates the existence range based on the irradiation point where the object is detected, and increases the number of irradiation points in the existence range in the scanning range more than the number of irradiation points in the other ranges. You can also. Thereby, for example, when the vehicle on which the monitoring device 10 is mounted is stopped, detailed information around the object at a short distance can be acquired.

[Distribution and integration]
In addition, each component of each illustrated apparatus does not necessarily need to be physically configured as illustrated. In other words, the specific form of distribution / integration of each device is not limited to that shown in the figure, and all or a part thereof may be functionally or physically distributed or arbitrarily distributed in arbitrary units according to various loads or usage conditions. Can be integrated and configured. For example, the detection unit 15 or the light emission control unit 16 may be connected as an external device of the monitoring device 10 via a network. Further, the functions of the monitoring device 10 described above may be realized by having the detection unit 15 or the light emission control unit 16 respectively connected to a network and cooperating. Further, the distance storage unit 15a and the timing storage unit 16a may have all or a part of each other, and the functions of the monitoring device 10 may be realized by being connected to a network and cooperating. Absent.

10 Monitoring device 11 Light source LD
12 LD driving unit 13 Scanning unit 14 Light receiving unit 15a Distance storage unit 15 Detection unit 16a Timing storage unit 16 Light emission control unit

Claims (4)

A light source that generates laser light;
A scanning unit that scans a laser beam irradiated by the light source in a predetermined scanning range;
A detection unit for detecting the object using reflected light of a laser beam reflected by the object existing in the scanning range;
When the object is detected by the detection unit, the irradiation density of the laser light included outside the predetermined range based on the irradiation point of the laser light where the object is detected in the scanning range is the first irradiation. the light source emit light so that the density, and has a light emission control unit for emitting the light source so that the irradiation density in the predetermined range is a second irradiation density greater than the first irradiation density ,
The light emission control unit prioritizes an irradiation point at which an object having the highest relative speed with respect to the own apparatus is detected among the plurality of objects over other irradiation points when the detection unit detects a plurality of objects. The monitoring device is characterized in that the light source emits light so that an irradiation density within a predetermined range with respect to the irradiation point becomes the second irradiation density . The scanning unit raster scans the laser light in the scanning range,
The light emission control unit increases or decreases the irradiation density by changing the length of the light emission interval of the light source or by changing the ratio of the scanning lines to be emitted to the light source among the scanning lines included in the scanning range. The monitoring device according to claim 1, characterized in that:   The detection unit includes a change in the distance from the monitoring device to the object measured at each irradiation point using the reflected light of the laser beam, a speed of the monitoring device, or a speed of a mounting device on which the monitoring device is mounted. The monitoring apparatus according to claim 1, wherein the object is detected based on a moving distance of the monitoring apparatus converted from a speed output by a sensor that measures the object. A monitoring method executed by a monitoring device,
The monitoring device is
A process of detecting the object using the reflected light of the laser beam reflected by the object existing within the scanning range for scanning the laser beam irradiated by the light source that generates the laser beam;
When the object is detected, the irradiation density of the laser beam included outside the predetermined range based on the irradiation point of the laser beam where the object is detected in the scanning range becomes the first irradiation density. It said light source is emitting, and executes a process of irradiation density within predetermined range is to emit the light such that the second irradiation density greater than the first irradiation density,
In the process of causing the light to be emitted, when a plurality of objects are detected, the irradiation point at which the object having the highest relative speed with respect to the own apparatus is detected is given priority over the other irradiation points. The light source is caused to emit light so that the irradiation density within a predetermined range with reference to the second irradiation density becomes the second irradiation density .

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