Patent Publication Number: US-2023143300-A1

Title: Detection system and detection method

Description:
TECHNICAL FIELD 
     The present invention relates to a detection system and a detection method. 
     Priority is claimed on Japanese Patent Application No. 2020-065033, filed Mar. 31, 2020, the content of which is incorporated herein by reference. 
     BACKGROUND ART 
     Patent Document 1 discloses a technique related to a peripheral monitoring system that detects a person in the vicinity of a work machine. According to the technique described in Patent Document 1, the peripheral monitoring system detects a surrounding obstacle. 
     CITATION LIST 
     Patent Document 
     Patent Document 1 
     
         
         Japanese Unexamined Patent Application, First Publication No. 2016-035791 
       
    
     SUMMARY OF INVENTION 
     Technical Problem 
     For the safety of workers, it is important to avoid a dangerous act such as non-wearing of protective equipment such as a helmet and a safety vest and walking while operating a smartphone at the site in which a work machine operates. Therefore, the supervisor must always pay attention to whether the dangerous act has been performed at the site, which places a heavy burden on the supervisor. 
     An object of the present invention is to provide a detection system and a detection method capable of easily detecting the presence or absence of a dangerous act. 
     Solution to Problem 
     According to a first aspect, a detection system includes an acquisition unit configured to acquire captured data from an imaging device that captures an image of a site, and a dangerous act determination unit configured to determine whether a person who performs a dangerous act is present at the site based on the captured data. 
     Advantageous Effects of Invention 
     According to the above aspect, the presence or absence of a dangerous act can be easily detected by using the detection system. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a schematic diagram showing a configuration of a work machine according to a first embodiment. 
         FIG.  2    is a diagram showing imaging ranges of a plurality of cameras provided in the work machine according to the first embodiment. 
         FIG.  3    is a diagram showing an internal configuration of a cab according to the first embodiment. 
         FIG.  4    is a schematic block diagram showing a configuration of a control device according to the first embodiment. 
         FIG.  5    is a table showing an example of information stored in the dangerous act dictionary data according to the first embodiment. 
         FIG.  6    is a flowchart showing an operation of the control device according to the first embodiment. 
         FIG.  7    is a diagram showing an example of a captured image by the camera according to the first embodiment. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     First Embodiment 
     Hereinafter, an embodiment of the present invention is described with reference to the drawings. 
     A detection system according to a first embodiment is realized by a work machine  100  arranged at the site. 
     &lt;&lt;Configuration of Work Machine  100 &gt;&gt; 
       FIG.  1    is a schematic diagram showing a configuration of a work machine  100  according to a first embodiment. 
     The work machine  100  operates at a construction site to construct a construction target such as earth. The work machine  100  according to the first embodiment is, for example, a hydraulic excavator. The work machine  100  includes an undercarriage  110 , a swing body  120 , work equipment  130 , and a cab  140 . Incidentally, the work machine  100  may be a work machine for a mine such as a mining excavator that operates in a mine with the site as a mine. 
     The undercarriage  110  movably supports the work machine  100 . The undercarriage  110  is, for example, a pair of right and left endless tracks. 
     The swing body  120  is supported by the undercarriage  110  to be swingable around a swing center. 
     The work equipment  130  is driven by hydraulic pressure. The work equipment  130  is supported by a front portion of the swing body  120  to be capable of driving in an up to down direction. The cab  140  is a space in which an operator gets in to operate the work machine  100 . The cab  140  is provided on a left front portion of the swing body  120 . 
     Here, a portion of the swing body  120  to which the work equipment  130  is attached is referred to as a front portion. In addition, in the swing body  120 , based on the front portion, a portion opposite to the front is referred to as a rear portion, a portion on a left side is referred to as a left portion, and a portion on a right side is referred to as a right portion. 
     &lt;&lt;Configuration of Swing Body  120 &gt;&gt; 
     A plurality of cameras  121  that capture an image of the periphery of the work machine  100  and a speaker  122  that outputs voice to the outside of the work machine  100  are provided in the swing body  120 . An exemplary example of the speaker  122  is a horn speaker.  FIG.  2    is a diagram showing imaging ranges of the plurality of cameras  121  provided in the work machine  100  according to the first embodiment. 
     Specifically, the swing body  120  is provided with a left rear camera  121 A that captures an image of a left rear region Ra of the periphery of the swing body  120 , a rear camera  121 B that captures an image of a rear region Rb of the periphery of the swing body  120 , a right rear camera  121 C that captures an image of a right rear region Rc of the periphery of the swing body  120 , and a right front camera  121 D that captures an image of a right front region Rd of the periphery of the swing body  120 . Incidentally, the imaging ranges of the plurality of cameras  121  may partially overlap each other. 
     The imaging ranges of the plurality of cameras  121  cover a range of an entire periphery of the work machine  100  excluding a left front region Re that is visually recognized from the cab  140 . Incidentally, the cameras  121  according to the first embodiment capture images of regions on left rear, rear, right rear, and right front sides of the swing body  120 , but are not limited thereto in another embodiment. For example, the number of the cameras  121  and the imaging ranges according to another embodiment may differ from the example shown in  FIGS.  1  and  2   . 
     Incidentally, as shown by the rear range Rb in  FIG.  2   , the left rear camera  121 A captures an image of a range of a left side region and a left rear region of the swing body  120 , but may capture an image of one region thereof. Similarly, as shown by the right rear range Rc in  FIG.  2   , the right rear camera  121 C captures an image of a range of a right side region and a right rear region of the swing body  120 , but may capture an image of one region thereof. Similarly, as shown by the right front range Rd in  FIG.  2   , the right front camera  121 D captures an image of a range of a right front region and the right side region of the swing body  120 , but may capture an image of one region thereof. In addition, in another embodiment, the plurality of cameras  121  may be used so that the entire periphery of the work machine  100  is set as the imaging range. For example, the left front camera that captures the image of the left front range Re may be provided, and the entire periphery of the work machine  100  may be set as the imaging range. 
     &lt;&lt;Configuration of Work Equipment  130 &gt;&gt; 
     The work equipment  130  includes a boom  131 , an arm  132 , a bucket  133 , a boom cylinder  131 C, an arm cylinder  132 C, and a bucket cylinder  133 C. 
     A proximal end portion of the boom  131  is attached to the swing body  120  via a boom pin  131 P. 
     The arm  132  connects the boom  131  and the bucket  133 . A proximal end portion of the arm  132  is attached to a distal end portion of the boom  131  via an arm pin  132 P. The bucket  133  includes blades that excavate earth or the like, and an accommodating portion that accommodates the excavated earth. A proximal end portion of the bucket  133  is attached to a distal end portion of the arm  132  via a bucket pin  133 P. 
     The boom cylinder  131 C is a hydraulic cylinder that operates the boom  131 . A proximal end portion of the boom cylinder  131 C is attached to the swing body  120 . A distal end portion of the boom cylinder  131 C is attached to the boom  131 . 
     The arm cylinder  132 C is a hydraulic cylinder that drives the arm  132 . A proximal end portion of the arm cylinder  132 C is attached to the boom  131 . A distal end portion of the arm cylinder  132 C is attached to the arm  132 . 
     The bucket cylinder  133 C is a hydraulic cylinder that drives the bucket  133 . A proximal end portion of the bucket cylinder  133 C is attached to the arm  132 . A distal end portion of the bucket cylinder  133 C is attached to a link member connected to the bucket  133 . 
     &lt;&lt;Configuration of Cab  140 &gt;&gt; 
       FIG.  3    is a diagram showing an internal configuration of the cab  140  according to the first embodiment. 
     A driver seat  141 , an operation device  142 , and a control device  143  are provided in the cab  140 . 
     The operation device  142  is a device to drive the undercarriage  110 , the swing body  120 , and the work equipment  130  by a manual operation of the operator. The operation device  142  includes a left operation lever  142 LO, a right operation lever  142 RO, a left foot pedal  142 LF, a right foot pedal  142 RF, a left traveling lever  142 LT, and a right traveling lever  142 RT. 
     The left operation lever  142 LO is provided on a left side of the driver seat  141 . The right operation lever  142 RO is provided on a right side of the driver seat  141 . 
     The left operation lever  142 LO is an operation mechanism that causes the swing body  120  to perform a swing operation and causes the arm  132  to perform a pulling or pushing operation. Specifically, when the operator of the work machine  100  tilts the left operation lever  142 LO forward, the arm  132  is pushed. In addition, when the operator of the work machine  100  tilts the left operation lever  142 LO backward, the arm  132  is pulled. In addition, when the operator of the work machine  100  tilts the left operation lever  142 LO in a right direction, the swing body  120  swings rightward. In addition, when the operator of the work machine  100  tilts the left operation lever  142 LO in a left direction, the swing body  120  swings leftward. Incidentally, in another embodiment, when the left operation lever  142 LO is tilted in a front to back direction, the swing body  120  may swing rightward or swing leftward, and when the left operation lever  142 LO is tilted in a right to left direction, the arm  132  may perform a pulling operation or a pushing operation. 
     The right operation lever  142 RO is an operation mechanism that causes the bucket  133  to perform an excavating or dumping operation and causes the boom  131  to perform a rising or lowering operation. Specifically, when the operator of the work machine  100  tilts the right operation lever  142 RO forward, a lowering operation of the boom  131  is executed. In addition, when the operator of the work machine  100  tilts the right operation lever  142 RO backward, a rising operation of the boom  131  is executed. In addition, when the operator of the work machine  100  tilts the right operation lever  142 RO in the right direction, a dumping operation of the bucket  133  is performed. In addition, when the operator of the work machine  100  tilts the right operation lever  142 RO in the left direction, an excavating operation of the bucket  133  is performed. Incidentally, in another embodiment, when the right operation lever  142 RO is tilted in the front to back direction, the bucket  133  may perform a dumping operation or an excavating operation, and when the right operation lever  142 RO is tilted in the right to left direction, the boom  131  may perform a rising operation or a lowering operation. 
     The left foot pedal  142 LF is arranged on a left side of a floor surface in front of the driver seat  141 . The right foot pedal  142 RF is arranged on a right side of the floor surface in front of the driver seat  141 . The left traveling lever  142 LT is pivotally supported by the left foot pedal  142 LF and is configured such that the inclination of the left traveling lever  142 LT and the pressing down of the left foot pedal  142 LF are linked to each other. The right traveling lever  142 RT is pivotally supported by the right foot pedal  142 RF and is configured such that the inclination of the right traveling lever  142 RT and the pressing down of the right foot pedal  142 RF are linked to each other. 
     The left foot pedal  142 LF and the left traveling lever  142 LT correspond to rotational drive of a left crawler belt of the undercarriage  110 . Specifically, when the operator of the work machine  100  tilts the left foot pedal  142 LF or the left traveling lever  142 LT forward, the left crawler belt rotates in a forward movement direction. In addition, when the operator of the work machine  100  tilts the left foot pedal  142 LF or the left traveling lever  142 LT backward, the left crawler belt rotates in a backward movement direction. 
     The right foot pedal  142 RF and the right traveling lever  142 RT correspond to rotational drive of a right crawler belt of the undercarriage  110 . Specifically, when the operator of the work machine  100  tilts the right foot pedal  142 RF or the right traveling lever  142 RT forward, the right crawler belt rotates in the forward movement direction. In addition, when the operator of the work machine  100  tilts the right foot pedal  142 RF or the right traveling lever  142 RT backward, the right crawler belt rotates in the backward movement direction. 
     The control device  143  includes a display  143 D that displays information related to a plurality of functions of the work machine  100 . The control device  143  is one example of a display system. In addition, the display  143 D is one example of a display unit. Input means of the control device  143  according to the first embodiment is a hard key. Incidentally, in another embodiment, a touch panel, a mouse, a keyboard, or the like may be used as the input means. In addition, the control device  143  according to the first embodiment is provided integrally with the display  143 D, but in another embodiment, the display  143 D may be provided separately from the control device  143 . Incidentally, when the display  143 D and the control device  143  are separately provided, the display  143 D may be provided outside the cab  140 . In this case, the display  143 D may be a mobile display. In addition, when the work machine  100  is driven by remote operation, the display  143 D may be provided in a remote operation room provided remotely from the work machine  100 . 
     Incidentally, the control device  143  may be configured by a single computer, or the configuration of the control device  143  may be divided into a plurality of computers, such that the plurality of computers may cooperate with each other to function as a detection system. That is, the work machine  100  may include a plurality of computers that function as the control device  143 . Incidentally, the above-mentioned one control device  143  is also one example of the detection system. 
     &lt;&lt;Configuration of Control Device  143 &gt;&gt; 
       FIG.  4    is a schematic block diagram showing the configuration of the control device  143  according to the first embodiment. 
     The control device  143  is a computer including a processor  210 , a main memory  230 , a storage  250 , and an interface  270 . 
     The camera  121  and the speaker  122  are connected to the processor  210  via the interface  270 . 
     Exemplary examples of the storage  250  include an optical disk, a magnetic disk, a magneto-optical disk, a semiconductor memory, or the like. The storage  250  may be an internal medium that is directly connected to a bus of the control device  143  or may be an external medium connected to the control device  143  via the interface  270  or a communication line. The storage  250  stores a program for realizing the monitoring of the periphery of the work machine  100 . In addition, the storage  250  stores in advance a plurality of images including an icon for displaying on the display  143 D. 
     The program may realize some of functions to be exhibited by the control device  143 . For example, the program may exhibit functions in combination with another program that is already stored in the storage  250  or in combination with another program installed in another device. Incidentally, in another embodiment, the control device  143  may include a custom large scale integrated circuit (LSI) such as a programmable logic device (PLD) in addition to the above configuration or instead of the above configuration. Exemplary examples of the PLD include a programmable array logic (PAL), a generic array logic (GAL), a complex programmable logic device (CPLD), and a field programmable gate array (FPGA). In this case, some or all of the functions to be realized by the processor  210  may be realized by the integrated circuit. 
     In addition, the storage  250  stores a human dictionary data D 1  for detecting a person and a dangerous act dictionary data D 2  for detecting a dangerous act. 
     The human dictionary data D 1  may be, for example, dictionary data of a feature amount extracted from each of a plurality of known images in which a person is reflected. Exemplary examples of the feature amount include histograms of oriented gradients (HOG), co-occurrence hog (CoHOG), or the like. 
       FIG.  5    is a table showing an example of information stored in the dangerous act dictionary data D 2  according to the first embodiment. 
     The dangerous act dictionary data D 2  stores feature data and warning data showing the feature of a person who performs a dangerous act for each type of dangerous acts to be detected. Exemplary examples of dangerous acts include non-wearing of a helmet, non-wearing of a safety vest, non-implementation of three-point support when rising and lowering the work machine  100 , walking while operating a smartphone, running, walking while putting a hand in a pocket, or the like. Incidentally, the three-point support is to support the body by putting one foot on the footrest unit of the work machine  100  and grasping the handrest unit of the work machine  100  with both hands. The feature data of the person who performs the dangerous act may be represented by, for example, the feature amount of the image, or may be represented by the skeleton data showing the skeleton posture of the person. Incidentally, the safety vest is a work garment for safety such as preventing a contact accident by improving visibility, for example, a work garment to which a reflector is attached. In addition, instead of the safety vest, safety trousers with a reflector may be used. 
     In addition, the dangerous act dictionary data D 2  may further store an additional condition in association with the feature data of the person who performs the dangerous act. When an additional condition is associated with the feature data, a feature matching the feature data is detected, and when the additional condition is satisfied, determination is made that the person who performs a dangerous act is present. When no additional condition is associated with the feature data, determination is made that the person who performs a dangerous act is present when a feature matching the feature data is detected. 
     For example, data showing features related to non-wearing of protective equipment such as a helmet, a safety vest, and safety trousers may be represented by the feature amount of the image of a person who does not wear the protective equipment. Incidentally, it should be noted that the feature amount may be represented not by the image of the whole body of a person but by the feature amount of the image of the place in which the protective equipment is worn. For example, the data showing the feature related to the non-wearing of the helmet may be represented by the feature amount of the image of the head portion of a person, and the data showing the feature related to the non-wearing of the safety vest may be represented by the feature amount of the image of the body portion of a person. 
     In addition, for example, the feature data related to the non-implementation of the three-point support may be represented by the feature amount of the image of the head portion of a person facing the outside of the work machine  100 . The feature data is associated with an additional condition indicating that a person is in the vicinity of the cab  140  of the work machine  100 . This is to detect the person jumping from the work machine  100 . 
     In addition, for example, the data showing the feature related to walking while operating the smartphone may be represented by the skeleton data showing the posture of the person who operates the smartphone. That is, it may be represented by skeleton data representing a posture in which the head portion is lowered and the hand is positioned in front of the chest. The feature data is associated with an additional condition indicating that the person moves at a speed equal to or higher than a first speed. 
     In addition, for example, the data showing the feature related to running may be represented by the skeleton data showing the posture of the running person. The feature data is associated with an additional condition indicating that the person moves at a speed equal to or higher than a second speed. The second speed is faster than the first speed. 
     In addition, for example, the data showing the feature related to walking while putting the hand in the pocket may be represented by the skeleton data showing the posture of the person walking with the hand in the pocket. That is, it may be represented by skeleton data representing a posture in which the arm is fixed in the vicinity of the waist. The feature data is associated with an additional condition indicating that the person moves at a speed equal to or higher than a first speed. 
     Incidentally, in other embodiments, the data showing the feature related to walking while operating the smartphone, the data showing the feature related to running, and the data showing the feature related to walking while putting the hand in the pocket may not be represented by skeleton data. For example, when detecting walking while operating the smartphone, running, walking while putting the hand in the pocket, or the like by using a discriminator based on pattern matching or machine learning by using an image, the feature amount of the image as data showing the feature may be stored in the dangerous act dictionary data D 2 . 
     Warning data depends on the type of the dangerous act. The warning data may be voice data in which a predetermined voice is recorded in advance. In addition, the warning data may be an image or text data showing a warning to be displayed on the display. In addition, the warning data may be light such as a warning light. Incidentally, in the example shown in  FIG.  5   , the warning data varies depending on the type of the dangerous act but is not limited thereto. In other embodiments, the warning data may be common warning data. For example, “Please do not do dangerous acts”, “Please follow the safety rules”, an icon indicating caution, an icon indicating danger, blinking display on the screen, or the like, that is, anything that calls caution in common regardless of the type of the dangerous act may be used. 
     Incidentally, the types of dangerous acts, the feature data, and the additional condition stored in the dangerous act dictionary data D 2  may differ depending at the site. For example, when walking while operating the smartphone is prohibited at one site and the act of stopping to operate the smartphone is not prohibited, the operation of the smartphone itself may be prohibited at another site. The dangerous act may be stipulated as rules at the site. 
     The processor  210  includes an acquisition unit  211 , an extraction unit  212 , a dangerous act determination unit  213 , a warning unit  214 , a recording unit  215 , and a transmission unit  216  by executing a program. 
     The acquisition unit  211  acquires captured images from the plurality of cameras  121 . 
     The extraction unit  212  extracts a partial image in which the person is reflected from the captured image acquired by the acquisition unit  211  based on the human dictionary data D 1 . Exemplary examples of a detection method of a person include pattern matching, object detection processing based on machine learning, or the like. 
     Incidentally, in the first embodiment, the extraction unit  212  extracts a person by using the feature amount of the image, but is not limited thereto. For example, in another embodiment, the extraction unit  212  may extract a person based on a measured value of light detection and ranging (LiDAR) or the like. 
     The dangerous act determination unit  213  determines whether the person extracted by the extraction unit  212  performs a dangerous act based on the dangerous act dictionary data D 2  that is the captured data and the partial image extracted by the extraction unit  212 . When determination is made that a person performs in a dangerous act, the dangerous act determination unit  213  specifies the type of the dangerous act. 
     The warning unit  214  outputs a warning voice from the speaker  122  when the dangerous act determination unit  213  determines that the person performs a dangerous act. 
     When determination is made that a person performs a dangerous act by the dangerous act determination unit  213 , the recording unit  215  stores the dangerous act history data associated with the captured image, the imaging time, the imaging position, and the type of the dangerous act acquired by the acquisition unit  211  in the storage  250 . Incidentally, the dangerous act history data does not necessarily have to be associated with all of the captured images, the imaging time, the imaging position, and the type of the dangerous act, and may include the captured image associated with at least one of the data related to the imaging time, the imaging position, the type of the dangerous act, and other dangerous acts. In addition, at least one of the data related to the imaging time, the imaging position, the type of the dangerous act, and other dangerous acts may be stored. In addition, the number of dangerous acts may be stored, and for example, the number of dangerous acts may be stored for each type of the dangerous act. 
     The transmission unit  216  transmits the dangerous act history data stored in the recording unit  215  to a server device (not shown). In addition, the transmission unit  216  does not necessarily have to transmit all of the captured images, the imaging time, the imaging position, and the type of the dangerous act, and may transmit a portion of the dangerous act history data. For example, information indicating the number of dangerous acts or the number of times for each type of dangerous act may be transmitted. 
     &lt;&lt;Detection Method of Dangerous Acts&gt;&gt; 
       FIG.  6    is a flowchart representing an operation of the control device  143  according to the first embodiment. 
     When the control device  143  starts periphery monitoring processing, the processing shown in  FIG.  6    is repeatedly executed. 
     The acquisition unit  211  acquires captured images from the plurality of cameras  121  (step S 1 ). Next, the extraction unit  212  executes extraction processing of a partial image in which a person is reflected by using the human dictionary data D 1  for each captured image acquired in the step S 1  and determines whether one or more partial images have been extracted (step S 2 ). When the partial image in which a person is reflected is not extracted (step S 2 : NO), the control device  143  ends the processing because a person who performs a dangerous act is not present. 
     When the partial image in which a person is reflected is extracted (step S 2 : YES), the dangerous act determination unit  213  selects one or more partial images extracted in the step S 2  one by one, and executes processing of a step S 4  to a step S 14  below (step S 3 ). 
     The dangerous act determination unit  213  selects the type of the dangerous act stored in the dangerous act dictionary data D 2  one by one and executes the processing of the step S 5  to the step S 14  below (step S 4 ). 
     The dangerous act determination unit  213  specifies the feature data associated with the type selected in the step S 4 , and generates the same type of feature data from the partial image selected in the step S 3  (step S 5 ). The dangerous act determination unit  213  calculates the degree of similarity between the feature data associated with the type selected in the step S 4  and the feature data of the partial image generated in the step S 5  (step S 6 ). The dangerous act determination unit  213  determines whether the degree of similarity of the feature data is equal to or higher than a predetermined threshold value (step S 7 ). 
     The dangerous act determination unit  213  determines whether the degree of similarity of the feature data is equal to or higher than a predetermined threshold value (step S 7 ). When the degree of similarity of the feature data is equal to or higher than the threshold value (step S 7 : YES), the dangerous act determination unit  213  determines whether there is an additional condition associated with the feature data (step S 8 ). When there is an additional condition (step S 8 : YES), the dangerous act determination unit  213  determines whether the partial image selected in the step S 3  satisfies the additional condition (step S 9 ). Incidentally, when the additional condition is a condition related to speed, the dangerous act determination unit  213  determines, for example, whether the distance between the position of the partial image extracted in the previous captured image and the position of the partial image selected in the step S 3  is equal to or higher than a predetermined distance. 
     When the additional condition is satisfied (step S 9 : YES), or when there is no additional condition in the matching feature data (step S 8 : NO), the dangerous act determination unit  213  determines that the person related to the partial image selected in the step S 3  performs the dangerous act of the type selected in the step S 4  (step S 10 ). The warning unit  214  outputs a warning voice from the speaker  122  based on the warning data associated with the type of the dangerous act selected in the step S 4  (step S 11 ). 
     The recording unit  215  starts recording a moving image (step S 12 ). That is, the recording unit  215  generates a moving image by recording the captured image of the camera  121  for a certain period of time after determining that the dangerous act is performed in the step S 10 . In the moving image, a person who performs a dangerous act is reflected. Then, the storage  250  stores the moving image generated in the step S 11 , the imaging time, the imaging position, and the dangerous act history data associated with the type of the dangerous act specified in the step S 10  (step S 13 ). Incidentally, the dangerous act history data recorded in the storage  250  is later transmitted to the server device by the transmission unit  216 . Incidentally, the imaging position is represented by, for example, position data acquired by a GNSS positioning device (not shown) of the work machine  100  at the time of capturing an image. 
     On the other hand, when the additional condition is not satisfied (step S 9 : NO), or when the degree of similarity of the feature data is less than the threshold value (step S 7 : NO), the dangerous act determination unit  213  determines that the person related to the partial image selected in the step S 3  does not perform the type of the dangerous act selected in the step S 4  (step S 14 ). 
     Incidentally, the processing shown in  FIG.  6    is only an example, and in another embodiment, the control device  143  may perform processing different from that shown in  FIG.  6   . For example, the dangerous act dictionary data D 2  according to another embodiment may not have an additional condition. In this case, the control device  143  may not have to perform the determination of the steps S 8  and S 9 . In addition, in another embodiment, the control device  143  may not perform at least one of the output of the warning voice in the step S 11  and the recording of the moving image in the step S 13 . In addition, in other embodiments, the warning may not have to be one based on voice, such as displaying on the display  143 D or emitting a warning light. In addition, the loop processing of at least one of the step S 3  and the step S 4  may be realized by parallel processing. 
     &lt;&lt;Effects&gt;&gt; 
     In this manner, the control device  143  can determine the dangerous act when the person reflected in the captured image performs the dangerous act. As a result, the control device  143  can reduce the burden on the supervisor to pay attention to the dangerous act at the site. In addition, the control device  143  can output a warning when the control device  143  determines the dangerous act. For example, the warning voice can be output toward the outside of the work machine  100 . As a result, the worker who performs the dangerous act in the vicinity of the work machine  100  can be aware of his or her own dangerous act and can alert also other workers to the dangerous act. For example, the warning image can be displayed on the display  143 D. As a result, the operator of the work machine  100  can be alerted. 
     In addition, the control device  143  can record the data related to the dangerous act in the storage  250 . For example, a moving image reflecting a scene of a dangerous act can be recorded in the storage  250 . As a result, the scene in which there has been the dangerous act can be stored. In addition, the control device  143  can transmit data related to the dangerous act to the server device. For example, the moving image reflecting a scene of the dangerous act can be transmitted to the server device. As a result, the supervisor at the site can later confirm whether the dangerous act is actually present by confirming the moving image. 
     Operation Example 
       FIG.  7    is a diagram representing an example of a captured image by the camera  121  according to the first embodiment. 
     When the camera  121  obtains a captured image as shown in  FIG.  6   , the extraction unit  212  of the control device  143  extracts two partial images G 1  and G 2  in the step S 2 . First, the dangerous act determination unit  213  executes the processing of the step S 5  to the step S 14  for each type of the dangerous act with respect to the partial image G 1 . At this time, the dangerous act determination unit  213  compares the feature data related to “non-wearing of the safety vest” with the feature data of a body portion Gil of the partial image G 1  in the step S 5  to the step S 7  and determines that the degree of similarity is high. Since the additional condition is not associated with the feature data related to “non-wearing of the safety vest”, the dangerous act determination unit  213  determines in the step S 10  that the person related to the partial image G 1  performs a dangerous act. Therefore, the warning unit  214  outputs a warning voice saying “Please wear a safety vest” from the speaker  122 . In addition, the recording unit  215  records a moving image including the image shown in  FIG.  6    in the storage  250 . 
     In addition, the dangerous act determination unit  213  executes the processing of the step S 5  to the step S 14  for each type of the dangerous act with respect to the partial image G 2 . The dangerous act determination unit  213  compares the feature data related to “non-wearing of the safety vest” with the feature data of a body portion G 21  of the partial image G 1  and determines that the degree of similarity is low. Similarly, the processing of the step S 5  to the step S 14  is executed for other types of dangerous acts, and since the degree of similarity is low in any of the dangerous acts and the additional condition is not satisfied, the dangerous act determination unit  213  determines that the person related to the partial image G 2  does not perform the dangerous act in the step S 14 . 
     OTHER EMBODIMENTS 
     The embodiments have been described above in detail with reference to the drawings; however, the specific configurations are not limited to the above-described configurations, and various design changes or the like can be made. Namely, in another embodiment, the order of the above-described processes may be appropriately changed. In addition, some of the processes may be executed in parallel. 
     In the embodiment described above, the work machine  100  includes the plurality of cameras  121  and the speakers  122 , but is not limited thereto. For example, in other embodiments, the camera or the speaker may be provided outside the work machine  100 . Exemplary examples of the speaker and the camera provided to the outside include a speaker and a camera installed at the site, a speaker and a camera provided in another work machine  100 , or the like. 
     The detection system according to the above-described embodiment may be provided outside the work machine  100 . 
     In addition, in another embodiment, a portion of the configurations constituting the detection system may be mounted inside the work machine  100 , and other configurations may be provided outside the work machine  100 . For example, a detection system may be configured such that the display  143 D is provided in a remote operation room provided remotely from the work machine  100 . In addition, in another embodiment, the plurality of computers described above or a single computer described above may all be provided outside the work machine  100 . For example, the detection system may include a combination of a fixed point camera installed at the site and one or a plurality of computers provided in a control room or the like in place of the control device  143  or in addition to the control device  143 . In this case, the computer provided outside the work machine  100  has the same configuration as a portion or the entire portion of the control device  143  shown in  FIG.  4   . A computer provided outside the work machine  100  may perform the processing shown in  FIG.  6    based on the captured image obtained from the fixed point camera. 
     In addition, the detection system according to the above-described embodiment outputs a warning voice from the speaker  122  of the work machine  100  and alerts a worker or a supervisor who performs a dangerous act in the vicinity of the work machine  100 . The present invention is not limited thereto. For example, the detection system of another embodiment may be provided with a speaker inside the cab  140  and alert the operator. Incidentally, the speaker may be provided as a buzzer provided in the cab or an integrated speaker provided in the display  143 D in the cab, and the speaker may be used to alert the operator. 
     In addition, the detection system according to the above-described embodiment outputs a warning voice from the speaker  122  of the work machine  100  but is not limited thereto. For example, the detection system of another embodiment may output a warning voice to a fixed speaker provided at the site. In addition, according to yet another embodiment, the detection system of the work machine  100  may output a warning voice to the speaker  122  of the other work machine  100  by vehicle-to-vehicle communication. 
     In addition, in the above-described embodiment, an example of determining a person who performs a dangerous act outside the work machine  100  has been described but is not limited thereto. For example, in another embodiment, the dangerous act of a person in the work machine  100  may be determined. For example, a camera may be provided inside the cab  140  so that an image of the operator can be captured, and the detection system may determine the dangerous act of the operator. In this case, an alert can be made by outputting a warning voice from a speaker provided in the cab or displaying an image or a text indicating a warning on the display  143 D. 
     In addition, the detection system according to the above-described embodiment determines, after extracting a person, the presence or absence of a dangerous act for the person but is not limited thereto. For example, in another embodiment, the presence or absence of the person who performs the dangerous act may be estimated directly from the captured image by using a learned model that estimates the presence or absence of a person who performs a dangerous act from the entire captured image. 
     In addition, the detection system according to the above-described embodiment records a moving image reflecting a scene of a dangerous act in the step S 12  described above, but is not limited thereto. For example, the detection system according to another embodiment may record the captured image acquired in the step S 1 , that is, the still image. 
     In addition, the detection system according to the above-described embodiment outputs a warning voice according to the type of the dangerous act, but is not limited thereto. For example, the detection system according to another embodiment may output a horn sound regardless of the type of the dangerous act. 
     In addition, in another embodiment, the detection system may calculate the degree of danger of a person who performs a dangerous act and determine whether to output the warning based on the degree of danger. For example, the degree of danger may be calculated based on the distance from the person who performs the dangerous act to the swing center of the work equipment  130 , and a warning may be output when the degree of danger exceeds the threshold value. 
     In addition, in another embodiment, the detection system (detection system) may be configured to include only the display  143 D among the display  143 D and the speaker  122 . In this case, the operator of the work equipment  130  and the supervisor at the site can alert based on the image or the text indicating the warning displayed on the display  143 D. 
     In addition, the work machine  100  according to the above-described embodiment is a hydraulic excavator, but is not limited thereto. For example, the work machine  100  according to another embodiment may be another work machine such as a dump truck, a bulldozer, or a wheel loader. 
     INDUSTRIAL APPLICABILITY 
     According to the above aspect, the presence or absence of the dangerous act can be easily detected by using the detection system. 
     REFERENCE SIGNS LIST 
     
         
         
           
               100 : Work machine 
               110 : Undercarriage 
               120 : Swing body 
               121 : Camera 
               130 : Work equipment 
               143 : Control device 
               211 : Acquisition unit 
               212 : Extraction unit 
               213 : Dangerous act determination unit 
               214 : Warning unit 
               215 : Recording unit 
               216 : Transmission unit