JP6681278B2 - Position detection system and position detection method - Google Patents

Description

  The present invention relates to a position detection system and a position detection method.

  Conventionally, there is known a system that detects the position of an object using a camera. For example, Patent Document 1 discloses a system for identifying the position of a position / orientation measured object including a self-luminous marker by detecting infrared rays emitted by the self-luminous marker using a marker detection camera. There is.

JP, 2007-71782, A

  However, the conventional system has room for improvement, for example, from the viewpoint of improving convenience.

  An object of the present invention made in view of such circumstances is to provide a position detection system and a position detection method with improved convenience.

  A position detection system according to an embodiment of the present invention includes a first imaging unit that acquires a first captured image of an object, a second imaging unit that acquires a second captured image of the object, and A control unit that calculates the position of the target object based on one captured image and the second captured image and identifies a plurality of target objects. When at least one of the plurality of objects is in a lost state and the at least one object cannot be identified, the control unit executes a re-identification process for the plurality of objects.

  In addition, a position detection method according to an embodiment of the present invention includes a first imaging unit that acquires a first captured image of an object and a second imaging unit that acquires a second captured image of the object. It is a position detection method in a position detection system provided. The position detecting method calculates a position of the target object based on the first captured image and the second captured image to identify a plurality of target objects, and at least one of the plurality of target objects. When one of the objects is lost, and at least one of the objects cannot be identified, a re-identification process is performed on the plurality of objects.

  According to the present invention, a position detection system and a position detection method with improved convenience can be provided.

It is a functional block diagram showing a schematic structure of a position detection system concerning one embodiment of the present invention. It is a schematic diagram explaining the position detection principle by the position detection system of FIG. It is a functional block diagram which shows schematic structure of the information display system using the position detection system of FIG. FIG. 4 is an external perspective view showing an example of the head mounted display of FIG. 3. FIG. 4 is a sequence diagram showing an example of information display processing by the information display system of FIG. 3. FIG. 2 is a functional block diagram showing a schematic configuration of an information display system including a plurality of head mounted displays and using the position detection system of FIG. 1.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a functional block diagram showing a schematic configuration of a position detection system 100 according to an embodiment of the present invention. The position detection system 100 according to the present embodiment includes a plurality of image pickup devices and an information processing device 130 configured to communicate with each image pickup device. In the present embodiment, as shown in FIG. 1, the position detection system 100 includes two imaging devices, a first imaging device 110 and a second imaging device 120, as a plurality of imaging devices. The position detection system 100 may include three or more imaging devices.

  FIG. 2 is a schematic diagram illustrating the principle of position detection by the position detection system 100 of FIG. In the position detection system 100 according to the present embodiment, the first image capturing device 110 and the second image capturing device 120 capture an image of the target object P that is the target of position detection, and the information processing device 130 causes the first image capturing device 110 2 The position of the object P is calculated based on the captured image acquired by the imaging device 120. The first imaging device 110 and the second imaging device 120 respectively image the target P from different directions, as shown in FIG. 2 as an example. In the present embodiment, the target P will be described as an infrared LED (Light Emitting Diode) that emits near-infrared rays of about 700 to 1500 nm, for example.

  Referring back to FIG. 1, the first imaging device 110 includes a control unit 111, a storage unit 112, a communication unit 113, and a first imaging unit 114. The first imaging device 110 images the target object P and transmits the captured image to the information processing device 130.

  The control unit 111 is a processor that controls and manages the entire first imaging device 110, including the functional blocks included in the first imaging device 110. The control unit 111 includes a processor such as a CPU (Central Processing Unit) that executes a program that defines a control procedure. The program executed by the processor is stored in, for example, the storage unit 112 or an external storage medium. The control unit 111 controls the imaging process performed by the first imaging unit 114, for example.

  The storage unit 112 has various memory devices, and stores various kinds of information, such as data necessary for the operation of the control unit 111, depending on the application. The storage unit 112 also has a device such as a RAM (Random Access Memory) that functions as a work memory. The storage unit 112 may store, for example, a captured image captured by the first image capturing unit 114 (hereinafter, also referred to as “first captured image”).

  The communication unit 113 performs various kinds of information transmission / reception by performing wired communication or wireless communication with the information processing device 130. For example, the first imaging device 110 transmits the first captured image to the information processing device 130 via the communication unit 113.

  The first imaging unit 114 images the object P. The first image capturing unit 114 includes an image sensor (image sensor) that captures an image projected on the element by converting light into an electric signal. In the present embodiment, the first imaging unit 114 is an infrared camera that detects near infrared light emitted by the object P.

  The second imaging device 120 includes a control unit 121, a storage unit 122, a communication unit 123, and a second imaging unit 124. The respective functions of the control unit 121, the storage unit 122, the communication unit 123, and the second imaging unit 124 are the same as those of the control unit 111, the storage unit 112, the communication unit 113, and the first imaging unit 114 of the first imaging device 110, respectively. Therefore, detailed description thereof is omitted here. In the present specification, the captured image captured by the second image capturing unit 124 is also referred to as “second captured image” below.

  The information processing device 130 includes a control unit 131, a storage unit 132, and a communication unit 133. The information processing device 130 calculates the position of the object P based on the captured images acquired by the first imaging device 110 and the second imaging device 120.

  The control unit 131 is a processor that controls and manages the entire information processing apparatus 130 including each functional block included in the information processing apparatus 130. The control unit 131 includes a processor such as a CPU that executes a program that defines a control procedure. The program executed by the processor is stored in, for example, the storage unit 132 or an external storage medium. The control unit 131 calculates the position of the detection target based on the first captured image acquired by the first imaging device 110 and the second captured image acquired by the second imaging device 120. Details of the process of calculating the position of the detection target by the control unit 131 will be described later.

  The storage unit 132 has various memory devices, and stores various kinds of information, such as data necessary for the operation of the control unit 131, depending on the application. The storage unit 132 also has a device such as a RAM that functions as a work memory. The storage unit 132 may store, for example, the first captured image and the second captured image acquired from the first imaging device 110 and the second imaging device 120, respectively. Further, the storage unit 132 may store, for example, a history of the calculated position of the object. The information processing apparatus 130 can calculate the displacement (trajectory) of the target object based on the history of the position of the target object.

  The communication unit 133 transmits and receives various types of information by performing wired communication or wireless communication with the first imaging device 110 and the second imaging device 120. For example, the information processing apparatus 130 acquires the first captured image and the second captured image from the first image capturing apparatus 110 and the second image capturing apparatus 120, respectively, via the communication unit 133.

  Next, the details of the process of calculating the position of the detection target by the information processing device 130 will be described with reference to FIG.

  In FIG. 2, the imaging range A of the first imaging device 110 and the imaging range B of the second imaging device 120 are virtually shown. That is, in FIG. 2, the imaging range A virtually represents the first captured image acquired by the first imaging device 110, and the imaging range B virtually represents the second captured image acquired by the second imaging device 120. Show. In the first captured image and the second captured image, the object P is reflected at predetermined positions on the image plane. In the first captured image and the second captured image, the coordinates of the position where the object P is reflected are determined, for example, with reference to the gazing points of the first imaging unit 114 and the second imaging unit 124, respectively.

In the present embodiment, the position vectors of the first imaging device 110 and the second imaging device 120 are indicated by vector c ₁ and vector c ₂ , respectively. Further, a direction vector from the first imaging device 110 to the object P is shown as a vector a, and a direction vector from the second imaging device 120 to the object P is shown as a vector b. The direction vector a is defined as, for example, a direction vector from the position of the image sensor included in the first imaging unit 114 toward the detection target P on the image plane of the first captured image. Similarly, the direction vector b is defined as a direction vector from the position of the image sensor included in the second image capturing unit 124 toward the object P on the image plane of the second captured image. The direction vector a and the direction vector b are calculated, for example, by the control unit 131 of the information processing device 130 based on the first captured image and the second captured image, respectively. In addition, in FIG. 2, the lengths of the direction vector a and the direction vector b are shown as an example. Further, the position vector of the object P is represented by the vector p.

The position vector p of the object P is represented by the following expression (1) using the position vector c ₁ and the direction vector a. The control unit 131 of the information processing device 130 sets the position vector p as in the following expression (1).

  In Expression (1), n is a real number, and is determined according to the distance from the sensor position of the first imaging unit 114 to the detection target P, for example. By calculating (determining) n, the position vector p is determined and the position of the object P is determined.

Here, the direction vector (here, vector d) from the second image pickup device 120 toward the object P is expressed by the following equation (2) using the position vector c ₂ of the second image pickup device 120. You can The control unit 131 calculates the direction vector d.

  Since the direction vector d shown in the above equation (2) is defined as the direction vector from the second imaging device 120 to the target P, the direction is equal to the direction vector b. Therefore, since the angle formed by the direction vector d and the direction vector b is 0 °, the magnitude of the outer product of the direction vector d and the direction vector b is 0. When this is expressed by an expression, it is expressed as the following expression (3).

  By solving the above equation (3) for n, the following equation (4) is derived.

  By substituting the above equation (4) into the above equation (1), the position vector p is expressed by the following equation (5).

In the above equation (5), the position vector c ₁ and the position vector c ₂ are determined by the positions where the first imaging device 110 and the second imaging device 120 are installed, respectively. Further, the direction vector a and the direction vector b can be calculated by the information processing apparatus 130 from the first captured image and the second captured image acquired by the first imaging device 110 and the second imaging device 120, respectively. Therefore, the information processing apparatus 130 can calculate the position vector p of the object P using the above equation (5). The control unit 131 calculates the position of the object P based on the direction vector d and the direction vector b as shown in Expressions (3) to (5). In particular, the control unit 131 calculates the position of the object P based on the value of the outer product of the direction vector d and the direction vector b, assuming that the value of the outer product is 0. In this way, the position detection system 100 can specify the position of the object P.

  Further, according to the position detection system 100 according to the present embodiment, the first imaging device 110 and the second imaging device 120 image the object P from different directions. Therefore, the position detection according to the present embodiment is compared with a system such as a stereo camera that calculates a distance using parallax based on an image captured from one direction using two cameras. The system 100 improves the accuracy of position detection.

  The position detection system 100 may specify the position of the target object P for each imaging frame by the first imaging device 110 and the second imaging device 120, or for each predetermined number of frames.

  Next, an application example of the position detection system 100 described above will be described. In this specification, an example in which the position detection system 100 is applied to specify the position of a head mounted display (HMD) which is a display device mounted on the head of a user will be described. In the information display system to which the position detection system 100 is applied, the position of the HMD is specified by the position detection system 100 described above, and information according to the specified position is displayed on the display unit included in the HMD.

  FIG. 3 is a functional block diagram showing a schematic configuration of an information display system 200 to which the position detection system 100 is applied. As shown in FIG. 3, the information display system 200 includes an HMD 140 in addition to the first imaging device 110, the second imaging device 120, and the information processing device 130 included in the position detection system 100. The information processing device 130 and the HMD 140 are configured to be communicable via a wire or wirelessly.

  FIG. 4 is an external perspective view showing an example of the HMD 140. The HMD 140 includes a substantially hemispherical mounting unit 141 that the user can wear on the head, a display unit 142 that displays information to the user when the user wears the HMD 140, and a light source 143. In the present embodiment, the HMD 140 will be described as including two light sources 143a and 143b, as shown in FIG. When the two light sources 143a and 143b are not distinguished, they are collectively referred to as the light source 143.

  Referring again to FIG. 3, the HMD 140 includes a display unit 142, a light source 143, a control unit 144, a storage unit 145, a communication unit 146, and an angular velocity detection unit 147.

  The display unit 142 displays information to the user who wears the HMD 140. The display unit 142 has a display such as a liquid crystal display (LCD: Liquid Crystal Display) or an organic EL display (OELD: Organic Electroluminescence Display) for displaying information, and a housing that holds the display. FIG. 4 shows a so-called immersive display unit 142 that has a housing that shields the user's line of sight from the outside, but the display unit 142 is not limited to the immersive display unit. The display unit 142 may be, for example, a so-called transmissive type (see-through type) that allows the user to visually recognize the outside world via the display unit 142.

  The light source 143 emits light detected by the first imaging device 110 and the second imaging device 120, and corresponds to the object P described in FIG. The light source 143 is an infrared LED that emits near-infrared light, similar to that described in FIG. 2, for example. In the present embodiment, the two light sources 143a and 143b are provided in the mounting portion 141 so as to be arranged in the front-rear direction when the user wears the HMD 140, as shown as an example in FIG.

  The control unit 144 is a processor that controls and manages the entire HMD 140 including each functional block included in the HMD 140. The control unit 144 is composed of a processor such as a CPU that executes a program that defines a control procedure. The program executed by the processor is stored in, for example, the storage unit 145 or an external storage medium. The control unit 144 displays various information on the display unit 142 based on, for example, the position of the user and the orientation of the user's head. Specifically, the control unit 144 causes the display unit 142 to display a virtual space that follows the position of the user and the orientation of the head. The position of the user is determined by the position of the HMD 140 worn by the user, which is specified by the information processing device 130. The orientation of the user's head includes, for example, the orientation of the head in the three axial directions or the change in orientation.

  The storage unit 145 has various memory devices, and stores various kinds of information, such as data necessary for the operation of the control unit 144, depending on the application. The storage unit 145 also has a device such as a RAM that functions as a work memory. Further, the storage unit 145 stores, for example, various data regarding the virtual space displayed on the display unit 142.

  The communication unit 146 has a communication interface that transmits and receives various types of information by performing wired communication or wireless communication with the information processing device 130. For example, the HMD 140 acquires information regarding the position of the HMD 140 specified by the information processing apparatus 130 based on the first captured image and the second captured image from the information processing apparatus 130 via the communication unit 146.

  The angular velocity detection unit 147 is a sensor that detects a change in the angular velocity of the HMD 140, for example. The angular velocity detector 147 is composed of, for example, a gyro sensor. The angular velocity detection unit 147 is not limited to the gyro sensor. The angular velocity detection unit 147 only needs to be able to detect the angle change of the HMD 140. Therefore, the angular velocity detector 147 may be configured by, for example, an acceleration sensor, an angle sensor, another motion sensor, or a combination of these sensors. Information regarding the change in the angular velocity detected by the angular velocity detection unit 147 is transmitted to the control unit 144. The control unit 144 can estimate the orientation of the user's head based on the information regarding the change in angular velocity acquired from the angular velocity detection unit 147.

  Next, a virtual space display process in the information display system 200 will be described with reference to FIG.

  First, the first imaging device 110 acquires the first captured image by capturing an image of the light source 143 (step S201).

  The first imaging device 110 transmits the acquired first captured image to the information processing device 130 (step S202).

  In addition, the second imaging device 120 acquires the second captured image by capturing the image of the light source 143 (step S203).

  The second imaging device 120 transmits the acquired second captured image to the information processing device 130 (step S204).

  The processes of steps S201 and S202 by the first imaging device 110 and the processes of steps S203 and S204 by the second imaging device 120 may be executed at the same time.

  When the information processing apparatus 130 acquires the first captured image and the second captured image from the first image capturing apparatus 110 and the second image capturing apparatus 120, respectively, the information processing apparatus 130 identifies the position of the HMD 140 based on the captured image acquired (step S205). ). Specifically, the information processing device 130 uses Expression (5) using, for example, the position of the first imaging device 110 and the position of the second imaging device 120, which are stored in advance in the storage unit 132, and the acquired captured image. Thus, the position of the HMD 140 is specified by calculating the position of the light source 143.

  The information processing device 130 transmits information on the specified position of the HMD 140 to the HMD 140 (step S206).

  The HMD 140 uses the angular velocity detection unit 147 to acquire information regarding changes in the angular velocity of the HMD 140 (step S207).

  Then, the HMD 140 estimates the orientation of the user's head based on the information regarding the change in the angular velocity acquired by the angular velocity detection unit 147 (step S208).

  The HMD 140 displays the virtual space on the display unit 142 based on the information regarding the position acquired from the information processing device 130 in step S206 and the head orientation estimated in step S208 (step S209).

  In this way, the information display system 200 displays the virtual space on the display unit 142 based on the position of the HMD 140 and the orientation of the user's head. In the information display system 200, the position of the HMD 140 is specified by applying the position detection system 100 described above, so that the position of the HMD 140 can be easily specified accurately.

  Next, with reference to FIG. 6, an example in which the position detection system 100 is applied to specify the positions of a plurality of HMDs 140 will be described.

  FIG. 6 is a functional block diagram showing a schematic configuration of an information display system 300 to which the position detection system 100 is applied. As shown in FIG. 6, the information display system 300 includes a plurality of HMDs 140-1 to 140-N in addition to the first imaging device 110, the second imaging device 120, and the information processing device 130 included in the position detection system 100. The information processing device 130 and the HMDs 140-1 to 140-N are configured to be communicable with each other by wire or wirelessly. Since the internal configuration of the HMDs 140-1 to 140-N is the same as the internal configuration of the HMD 140 shown in FIG. 3, the description thereof is omitted in FIG. Further, in the following description, the HMDs 140-1 to 140-N will be simply referred to as the HMD 140 unless otherwise distinguished.

  The control unit 131 can specify the position of the HMD 140 by the processing shown in steps S201 to S205 of FIG. When the positions of the plurality of HMDs 140-1 to 140-N are specified as illustrated in FIG. 6, the control unit 131 determines which of the light sources 143 is the position of which HMD 140 for each of the N HMDs 140. I have specified it. Hereinafter, that the control unit 131 specifies which light source 143 corresponds to which HMD 140 among the plurality of light sources 143 is also referred to as the control unit 131 "identifies" the plurality of light sources 143.

  The control unit 131 executes the identification process of the light source 143, for example, when the business of the facility using the HMD 140 is started. The control unit 131 sequentially turns on the light sources 143 of the HMDs 140-1 to 140-N, for example. Then, the control unit 131 associates the position of the light source 143 newly detected when the light source 143 of the HMD 140-1 is turned on as the position of the HMD 140-1, and similarly, for the HMD 140-2 to HMD 140-N. Also, which light source 143 corresponds to the position of HMD140-2 to HMD140-N is matched.

  Once the identification processing is executed, the control unit 131 causes the storage unit 132 to store the history of the position of the HMD 140 (the position of the light source 143) after that, and keeps track of which light source 143 corresponds to which HMD 140. You can

  By the way, under a specific situation, the information processing apparatus 130 may be in a state where the position of the light source 143 of the HMD 140 cannot be temporarily specified. For example, when a certain light source 143 is hidden by an obstacle, it may not be reflected in the captured image of the first imaging device 110 or the second imaging device 120. The state in which the light source 143 is not reflected in the captured image in this manner is hereinafter referred to as a “mask state”. In the masked state, the control unit 131 cannot calculate the direction vector a or the direction vector b, and cannot specify the position of the light source 143 by the above equation (5).

  Further, for example, the light sources 143 of two or more HMDs 140 may be arranged in series in the gaze direction of the first imaging device 110 or the second imaging device 120, so that the plurality of light sources 143 may overlap in the captured image. The state in which the plurality of light sources 143 overlap in the captured image in this manner is hereinafter referred to as a “cascade state” in the present specification. In the cascade state, the control unit 131 erroneously determines the positions of the light sources 143 by mistaking the positions of the light sources 143 when the overlapping state of the light sources 143 in the captured image is resolved. there is a possibility.

  Hereinafter, in this specification, the mask state and the cascade state are collectively referred to as a “lost state”.

  When the light source 143 is in the masked state, the number of light sources 143 is reduced in at least one of the first captured image and the second captured image. Further, even when the light sources 143 are in the cascade state, the plurality of light sources 143 overlap in at least one of the first captured image and the second captured image, so that the number of light sources 143 shown in the captured image is reduced. As described above, when the number of the light sources 143 decreases in at least one of the first captured image and the second captured image, the control unit 131 of the information processing device 130 determines that the light sources 143 have become the lost state.

  When the light source 143 of some of the HMDs 140-1 to 140-N continues to be in the lost state, the control unit 131 determines that the light source 143 of some of the light sources 143 is the light source 143 even after the light source 143 recovers from the lost state. It may not be possible to associate with the HMD 140. That is, the control unit 131 may not be able to identify the light source 143 due to the lost state. For example, when the two light sources 143 are in the lost state, and after returning from the lost state after a sufficiently long time has passed, the history of the positions of the two light sources 143 in the lost state is tracked until immediately before the lost state. However, the control unit 131 cannot determine which HMD 140 the restored light source 143 corresponds to.

  In this way, when the control unit 131 cannot identify at least one light source 143 due to the lost state, the control unit 131 cannot display appropriate information on the display unit 142 of the HMD 140. Therefore, in this case, the control unit 131 once turns off all the light sources 143 and then executes the identification process again. Hereinafter, re-execution of the identification process is also referred to as execution of “re-identification process”.

  When the light source 143 cannot be identified due to the lost state, the control unit 131 can execute the re-identification process at various timings.

  For example, the control unit 131 may execute the re-identification process when the positions of all the light sources 143 can be calculated. Thereby, the control unit 131 can associate all the HMDs 140-1 to 140-N with the light source 143.

  Further, the control unit 131 executes the re-identification processing at the stage where the positions of the light sources 143 (for example, 95% of the light sources 143) of a predetermined ratio with respect to the number of all the light sources 143 can be calculated. Good. Thereby, even if there is a light source 143 that does not return for a long time in the lost state, the control unit 131 associates the light source 143 whose position can be calculated with the HMDs 140-1 to 140-N. be able to.

  Further, the control unit 131 may execute the re-identification process at a stage when at least one light source 143 has returned from the lost state and the position can be calculated. In addition, the control unit 131 may execute the re-identification processing at a stage when a predetermined time has elapsed since at least one light source 143 was in the lost state.

  In this way, the position detection system 100 executes the re-identification processing when at least one light source 143 cannot be identified due to the lost state. As a result, which HMD 140 the plurality of light sources 143 correspond to can be associated again, and the convenience of the position detection system 100 is improved.

  It should be noted that the present invention is not limited to the above-described embodiment, and various modifications and changes can be made. For example, the functions and the like included in each component can be rearranged so as not to logically contradict, and a plurality of components can be combined into one or divided.

  For example, in the above-described embodiment, the position detection system 100 has been described as including the two imaging devices 110 and 120, but the position detection system 100 may include three or more imaging devices. When the position detection system 100 includes three or more image capturing devices, the information processing device 130 can specify the position of the target object P based on the captured images acquired by any two image capturing devices. In this case, even if the target P is not displayed in the images captured by some of the image capturing devices due to being blocked by an obstacle, for example, the information processing apparatus 130 may capture another image of the target P. The position of the object P can be specified using the image.

  Further, in the above application example, the case where the HMD 140 includes the two light sources 143a and 143b has been described, but the HMD 140 includes not only two light sources. The HMD 140 may include one light source or three or more light sources.

  Further, in the above application example, the case where the HMD 140 includes the light source 143 has been described, but the application example is not limited to this. The light source 143 may be included in a device other than the HMD 140, and in this case, the information processing device 130 can identify the position of the device including the light source.

  The HMD 140 may also send information regarding the orientation of the user's head to an external device such as the information processing device 130. With this configuration, the convenience of the information display system 200 is further improved as described below.

  For example, the information processing device 130 that has received the information regarding the orientation of the user's head can display a predetermined image based on the position of the HMD 140 and the orientation of the user's head on, for example, an external display device. The predetermined image may include various images such as an image substantially the same as the image displayed on the HMD 140 and a map image showing the position and orientation of the user in the virtual space. Here, when the information display system 200 includes a plurality of HMDs 140, the information processing apparatus 130 causes the second HMD 140 to display an image displayed on the first HMD 140, and indicates the positions and orientations of a plurality of users. Map images can be displayed on a plurality of HMDs 140.

  Further, the information processing device 130 that has received the information regarding the orientation of the user's head can also predict the direction in which the user's position will be displaced next, based on the information regarding the orientation.

  In the above application example, the HMD 140 may be able to execute all the processes performed by the information processing device 130. At this time, the information display system 200 may include the first imaging device 110, the second imaging device 120, and the HMD 140. At this time, the HMD 140 is configured to be communicable with the first imaging device 110 and the second imaging device 120 via a wire or wirelessly.

100 Position Detection System 110 First Imaging Device 111, 121, 131, 144 Control Unit 112, 122, 132, 145 Storage Unit 113, 123, 133, 146 Communication Unit 114 First Imaging Unit 120 Second Imaging Device 124 Second Imaging Part 130 Information processing device 140 Head mounted display (HMD)
141 mounting unit 142 display unit 143 light source 147 angular velocity detection unit 200, 300 information display system

Claims (8)

A first imaging unit that acquires a first captured image of the object;
A second imaging unit that acquires a second captured image of the object;
A control unit that calculates the position of the target object based on the first captured image and the second captured image and identifies a plurality of the target objects;
The control unit performs re-identification processing on the plurality of objects when at least one of the plurality of objects is in a lost state and at least one of the objects cannot be identified ,
The control unit is
A position vector of the object is set based on the first captured image,
Calculating a first direction vector from the second imaging unit to the object using the set position vector,
Calculating a second direction vector from the second imaging unit to the object based on the second captured image,
Calculating the position of the object based on the position vector of the object represented by the following equation (1), which is calculated based on the value of the cross product of the first direction vector and the second direction vector, Position detection system.

However, the vector p represents the position vector of the target object, the vector a represents the direction vector from the first imaging unit to the target object, the vector b represents the second direction vector, and the vector c ₁ is the _first vector . 1 shows the position vector of the image pickup unit, and vector c ₂ shows the position vector of the second image pickup unit.   The position detection system according to claim 1, wherein the control unit re-identifies if the number of the objects whose positions can be calculated satisfies a predetermined condition when at least one of the objects cannot be identified. A position detection system that performs processing.   The position detection system according to claim 2, wherein the control unit executes the re-identification process when the positions of all the plurality of objects can be calculated.   The position detection system according to claim 2, wherein the control unit performs the re-identification processing when a ratio of the number of the objects whose positions can be calculated to the number of all the plurality of objects is equal to or more than a predetermined ratio. A position detection system.   The position detection system according to claim 2, wherein the control unit executes the re-identification process when the position of at least one of the objects in the lost state can be calculated. Position detection system.   The position detection system according to claim 1, wherein the control unit executes the re-identification processing when a predetermined time has elapsed after at least one of the objects is in a lost state.   The position detection system according to any one of claims 1 to 6, wherein the object is a light source, and the control unit executes re-identification processing by sequentially lighting the plurality of objects. Detection system. A position detection method in a position detection system, comprising: a first imaging unit that acquires a first captured image of an object; and a second imaging unit that acquires a second captured image of the object,
Calculating a position of the object based on the first captured image and the second captured image, and identifying a plurality of the objects;
Wherein at least one of the plurality of objects become lost state, viewed free it becomes impossible to identify the at least one of the object, and performing the re-identification process with respect to the plurality of objects, and
The calculation of the position of the object in the identifying step is
Setting a position vector of the object based on the first captured image;
Calculating a first direction vector from the second imaging unit to the object using the set position vector;
Calculating a second direction vector from the second imaging unit to the object based on the second captured image;
Calculating the position of the target object based on the position vector of the target object represented by the following equation (2), which is calculated based on the value of the cross product of the first direction vector and the second direction vector. And a position detection method including and .

However, the vector p represents the position vector of the target object, the vector a represents the direction vector from the first imaging unit to the target object, the vector b represents the second direction vector, and the vector c ₁ is the _first vector . 1 shows the position vector of the image pickup unit, and vector c ₂ shows the position vector of the second image pickup unit.

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