Patent Publication Number: US-2017374277-A1

Title: Image pickup apparatus, image pickup method, and recording medium for imaging plural subjects or a single subject

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2016-124913, filed Jun. 23, 2016, the entire contents of which are incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a technique of imaging plural subjects or a single subject. 
     2. Description of the Related Art 
     In recent, flight devices or so-called drone-type flying devices are widely used in various fields, which are provided with four propulsion units using rotor blades driven by electric motors. Particularly, the drone-type flying device with a digital camera fixed on is used for performing an imaging operation at an unreachable high place which is very dangerous for a human to perform operation. The drone-type flying devices having the digital camera have come into wide use by making use of a timer function of the digital camera and a remote control operation. 
     When the drone-type flying device is used to image a subject, an operator of the drone-type flying device is required to control the drone-type flying device to move the digital camera fixed to the drone-type flying device to a position appropriate for imaging the subject. 
     A conventional technique for solving the above inconvenience is disclosed in Japanese Unexamined Patent Publication No. 2004-118087, which technique uses a photo balloon controlled by a signal sent from a cellular phone. Receiving from the cellular phone a signal of requesting for performing an imaging operation, the photo-balloon moves in the air toward an area including a position indicated by position data contained in the received signal, and operates its image pickup unit to image the subject, when it is determined that the photo-balloon has reached the area. 
     SUMMARY OF THE INVENTION 
     According to one aspect of the invention, there is provided an image pickup apparatus which comprises a propulsion unit which is used for propulsion of the image pickup apparatus, an image pickup unit which images plural subjects or a single subject, and a controlling unit which controls the propulsion unit to move the image pickup apparatus such that at least two out of the plural subjects and the image pickup unit do not interfere in position with each other, or such that the single subject and the image pickup unit do not interfere in position with each other, and instructs the image pickup unit to image the plural subjects or the single subject. 
     According to another aspect of the invention, there is provided an image pickup method in an image pickup apparatus, the image pickup apparatus being provided with a controlling unit, a propulsion unit, and an image pickup unit for imaging plural subjects or a single subject, the image pickup method comprising steps of making the controlling unit control the propulsion unit to move the image pickup apparatus such that at least two out of the plural subjects and the image pickup unit do not interfere in position with each other, or such that the single subject and the image pickup unit do not interfere in position with each other, and making the controlling unit instruct the image pickup unit to image the plural subjects or the single subject. 
     According to still other aspect of the invention, there is provided a non-transitory computer-readable recording medium with a computer program stored thereon, the computer program prepared for making a computer control an image pickup apparatus, wherein the image pickup apparatus is provided with a propulsion unit for propulsion of the image pickup apparatus and an image pickup unit for imaging plural subjects or a single subject, and the computer program, when installed on the computer, making the computer control the propulsion unit to move the image pickup apparatus such that at least two out of the plural subjects and the image pickup unit do not interfere in position with each other, or such that the single subject and the image pickup unit do not interfere in position with each other, and making the computer instruct the image pickup unit to image the plural subjects or the single subject. 
     Additional objects and advantages of the invention will be set forth in the following description, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter. 
    
    
     
       BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWING 
       The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the inventions, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the invention. 
         FIG. 1  is a view showing an example of an appearance of a flight apparatus commonly used in embodiments of the invention, which apparatus operates as an image pickup apparatus of a flight type. 
         FIG. 2  is a view showing an example of a system configuration of the flight apparatus having the structure shown in  FIG. 1 . 
         FIG. 3  is a view for explaining a first embodiment of the invention. 
         FIG. 4  is a flow chart of an image pickup operation controlling process performed by the flight apparatus according to the first embodiment of the invention. 
         FIG. 5  is a view for explaining a second embodiment of the invention. 
         FIG. 6  is a flow chart of the image pickup operation controlling process performed by the flight apparatus according to the second embodiment of the invention. 
         FIG. 7  is a view for explaining a third embodiment of the invention. 
         FIG. 8  is a flow chart of the image pickup operation controlling process performed by the flight apparatus according to the third embodiment of the invention. 
         FIG. 9  is a view for explaining a fourth embodiment of the invention. 
         FIG. 10  is a flow chart of the image pickup operation controlling process performed by the flight apparatus according to the fourth embodiment of the invention. 
         FIG. 11  is a flow chart of the imaging controlling operation process performed by the flight apparatus according to a fifth embodiment of the invention. 
         FIG. 12  is a flow chart of the imaging controlling operation process performed by the flight apparatus according to a sixth embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The embodiments of the present invention are described with reference to the accompanying drawings in detail. An image pickup apparatus according to the embodiments of the invention is provided with a propulsion unit, an image pickup unit, and a controlling unit. The propulsion unit serves to propel the image pickup apparatus in the air. The image pickup unit serves to image plural subjects or a single subject. The image pickup apparatus according to the embodiments of the invention is a so-called flight apparatus of a drone-type. The controlling unit controls the propulsion unit to move the flight apparatus such that at least two out of the plural subjects and the image pickup unit do not interfere in position with each other, or such that the single subject and the image pickup unit do not interfere in position with each other, thereby allowing the image pickup unit to image the plural subjects or the single subject. 
       FIG. 1  is a perspective view showing an example of the appearance of the flight apparatus  100 , which are commonly used in the respective embodiment of the invention. The flight apparatus  100  operates as the image pickup apparatus of a flight type. 
     As shown in  FIG. 1 , the main frame  101  of the flight apparatus  100  is equipped with four circular motor frames (support units)  102 . The motor frame  102  supports a motor  104 . The motor shaft of the motor  104  has a rotor blade  103  firmly fixed thereon. Four sets of the motors  104  and rotor blades  103  compose a propulsion unit. 
     The main frame  101  contains a circuit box  105 . The circuit box  105  stores a motor driver for driving the motors  104 , a controller, and sensors. A camera (an image pickup unit)  106  is installed on a lower part of the main frame  101 . 
       FIG. 2  is a view showing an example of a system configuration of the flight apparatus  100  having the structure shown in  FIG. 1 . The flight apparatus  100  is commonly used in the embodiments of the invention described below. 
     As shown in  FIG. 2 , a controller  201  is connected with a camera system  202 , a flight sensor  203 , a touch sensor (a contact sensing unit)  204 , motor drivers (# 1  to # 4 )  205 , and a power sensor  206 . The camera system  202  includes the camera  106  (Refer to  FIG. 1 ). The flight sensor  203 , for instance, consists of a geomagnetic sensor, an acceleration sensor, a gyro sensor, and a GPS sensor (a Global Positioning Sensor). The motor drivers (# 1  to # 4 )  205  drive the motors (# 1  to # 4 )  104  (Refer to  FIG. 1 ), respectively. 
     The power sensor  206  supplies the motor drivers  205  with power while monitoring a voltage of a battery  207 . A push button which can sense contact may be used in place of the touch sensor  204 . Although not shown in  FIG. 2 , the power of the battery  207  is supplied to a control unit of each of the units  201  to  206 , too. 
     The controller  201  receives information representing a posture of the body of the flight apparatus  100  from the flight sensor  203  in real time. Further, the controller  201  sends each of the motor drivers (# 1  to # 4 )  205  a pulse-wide modulated power-instruction signal based on a duty ratio, while monitoring the voltage of the battery  207  through the power sensor  206 . Receiving the power-instruction signals, the motor drivers (# 1  to # 4 )  205  control rotational speeds of the motors (# 1  to # 4 )  104 , respectively. 
     The controller  201  controls the camera system  202  to adjust an image pickup operation of the camera  106  (Refer to  FIG. 1 ). 
     The controller  201 , the camera system  202 , the flight sensor  203 , the motor drivers (# 1  to # 4 )  205 , the power sensor  206  and the battery  207  shown in  FIG. 2  are stored in the circuit box  105  of the main frame  101  shown in  FIG. 1 . Although not clearly shown in  FIG. 1 , the touch sensor  204  is attached on the main frame  101  in  FIG. 1  and/or on the motor frame  102  to detect a difference between an electric physical quantity generated while an operator (a user) touches the frame(s)  101  and/or  102  and an electric physical quantity generated while the operator (the user) does not touch the frame(s)  101  and/or  102 . 
     First Embodiment of the Invention 
     The operation of the flight apparatus  100  having the configuration shown in  FIG. 2  is described hereinafter.  FIG. 3  is a view for explaining a first embodiment of the invention, in which the flying light apparatus  100  and a subject group including the plural subjects are illustrated.  FIG. 4  is a flow chart of an image pickup operation controlling process performed by the flight apparatus  100  according to the first embodiment of the invention. The image pickup operation controlling process is realized by a CPU (a Central Processing Unit) built in the controller  201  of  FIG. 2 , when a control program stored in a memory (not shown) built in the controller  201  is executed by the CPU. 
     As shown in  FIG. 3 , in the first embodiment of the invention, the controller  201  of the flight apparatus  100  detects a line of the plural subjects belonging to the subject group by means of the camera  102  and the camera system  202  and confirms a longitudinal direction of the line of the subjects. Further, the controller  201  moves the flight apparatus  100  in the air to a position in the direction perpendicular to the detected longitudinal direction of the line of the plural subjects, and then instructs the camera  102  and the camera system  202  to perform the image pickup operation at the current position. 
     The operation of the controller  201  in the first embodiment of the invention is specifically described with reference to the flow chart in  FIG. 4 . 
     The controller  201  watches a voltage variation of the touch sensor  204  to repeatedly judge whether the flight apparatus  100  has left a hand of the user or whether the flight apparatus  100  has been thrown by the user (step S 401  in  FIG. 4 ). 
     When it is determined that the flight apparatus  100  has left the hand of the user or the flight apparatus  100  has been thrown by the user (YES at step S 401 ), the controller  201  controls the motor drivers (# 1  to # 4 )  205  to drive the motors (# 1  to # 4 )  104  and rotor blades  103 , thereby making the flight apparatus  100  fly through the air to detect the line of the subject group as shown in  FIG. 3  (step S 402 ). 
     More specifically, the controller  201 , for example, performs a face recognition process on image data obtained by the camera  102  and the camera system  202  to recognize the faces of the plural subjects. Then, the controller  201  confirms a state in which these recognized faces forma line, thereby detecting the line of the subject group. Further, once having confirmed a state in which the line of the subject group remains still, the controller  201 , for example, repeatedly performs the face recognition process on the image data to continuously capture the faces of the plural subjects. 
     When the flight apparatus  100  flies through the air to detect the line of the subject group (step S 402 ), the controller  201  judges whether the line of the subject group has satisfactorily been detected (step S 403 ). 
     When it is determined that the line of the subject group has not been detected (NO at step S 403 ), the controller  201  returns to the process of step S 402  and tries to detect the line of the subject group, again. 
     When it is determined that the line of the subject group has been detected (YES at step S 403 ), the controller  201  performs an image processing on the image data obtained by the camera  102  and the camera system  202 , whereby controlling the motor drivers (# 1  to # 4 )  205  to drive the motors (# 1  to # 4 )  104  and rotor blades  103  to make the flight apparatus  100  fly through the air to the position in the direction perpendicular to the longitudinal direction of the line of the subject group, as shown in  FIG. 3  such that the camera  102  is allowed to image the front faces of the subject group therefrom (a flight controlling process, step S 404 ). 
     After performing the flight controlling process at step S 404 , the controller  201  judges whether the camera  102  has been brought to the position in the direction perpendicular to the longitudinal direction of the line of the subject group (step S 405 ). 
     When it is determined that the camera  102  has not been brought to the position (NO at step S 405 ), the controller  201  returns to the process of step S 404 , and tries to perform the flight controlling process, again. 
     When it is determined that the camera  102  has been brought to the position (YES at step S 405 ), the controller  201  controls the camera system  202  to instruct the camera  102  to image the subject group at the position (step S 406 ). At this time, in accordance with a result of the face recognition process performed on the subjects by the controller  201 , the camera system  202  performs an auto focusing control operation and an auto exposure controlling operation of the camera  102 . And then the controller  201  finishes the image pickup operation controlling process in the first embodiment of the invention. 
     With availability of an autonomous control of the flight apparatus  100  based on the operation of the controller  201  in the first embodiment described above, simply throwing the flight apparatus  100  in the air, the user can make the camera  102  of the flight apparatus  100  image the plural subjects belonging to the line of the subject group from a front and appropriate position of the subject group in an extremely simple manner. 
     Second Embodiment of the Invention 
       FIG. 5  is a view for explaining a second embodiment of the invention, in which the sun, the flying light apparatus  100  and a subject group including plural subjects are illustrated.  FIG. 6  is a flow chart of the image pickup operation controlling process performed by the flight apparatus  100  according to the second embodiment of the invention. Similarly to the process of  FIG. 4  in the first embodiment, the image pickup operation controlling process is realized by the built-in CPU of the controller  201  of  FIG. 2 , when the control program stored in the memory (not shown) built in the controller  201  is executed by the CPU. 
     As shown in  FIG. 5 , in the second embodiment of the invention, the controller  201  of the flight apparatus  100  moves the flight apparatus  100  to a position, at which a shadow of the flight apparatus  100  does not overlap with at least one subject belonging to the plural subjects or a single subject, and instructs the camera  102  and the camera system  202  to perform the image pickup operation at the position. 
     The operation of the controller  201  in the second embodiment of the invention is specifically described with reference to the flow chart of  FIG. 6 . 
     The controller  201  repeatedly judges whether the flight apparatus  100  has left the hand of the user or whether the flight apparatus has been thrown by the user (step S 601  in  FIG. 6 ), similarly to the process at step S 401  in  FIG. 4  in the first embodiment of the invention. 
     When it is determined that the flight apparatus  100  has left the hand of the user or the flight apparatus  100  has been thrown by the user (YES at step S 601 ), the controller  201  controls the motor drivers (# 1  to # 4 )  205  to drive the motors (# 1  to # 4 )  104  and rotor blades  103 , thereby making the flight apparatus  100  fly through the air to detect the plural subjects or the single subject as shown in  FIG. 5  (step S 602 ). 
     More specifically, the controller  201 , for example, performs the face recognition process on image data obtained by the camera  102  and the camera system  202  to recognize the faces of the plural subjects or the face of the single subject. Then, the controller  201  detects the plural subjects or the single subject. Further, similarly to the first embodiment, once having confirmed a state in which the plural subjects or the single subject remains still, the controller  201 , for example, repeatedly performs the face recognition process on the image data to continuously capture the faces of the plural subjects or the face of the single subject. 
     When the flight apparatus  100  flies through the air to detect the plural subjects or the single subject (step S 602 ), the controller  201  judges whether the plural subjects or the single subject has been detected satisfactorily (step S 603 ). 
     When it is determined that the plural subjects or the single subject has not been detected (NO at step S 603 ), the controller  201  returns to the process of step S 602  and tries to detect the plural subjects or the single subject, again. 
     When it is determined that the plural subjects or the single subject has been detected (YES at step S 603 ), the controller  201 , for example, estimates an azimuth of the sun based on information output from the geomagnetic sensor of the flight sensor  203 . Further, the controller  201  performs the image processing on information of the azimuth of the sun and the image data obtained by the camera  102  and the camera system  202  to detect the shadow of the flight apparatus  100  (step S 604 ). 
     The controller  201  judges whether the detected shadow of the flight apparatus  100  overlaps with the plural subjects or the single subject detected at steps S 602  and S 603  (step S 605 ). 
     When it is determined that the shadow of the flight apparatus  100  overlaps with the plural subjects or the single subject (YES at step S 605 ), then the controller  201 , while keeping capturing the plural subjects or the single subject, controls the motor drivers (# 1  to # 4 )  205  to drive the motors (# 1  to # 4 )  104  and rotor blades  103 , thereby making the flight apparatus  100  fly through the air, for example, for a fixed distance in a random direction (step S 606 ). 
     Thereafter, the controller  201  returns to the process of step S 604 , and detects the shadow of the flight apparatus  100 , again and judges whether the detected shadow of the flight apparatus  100  overlaps with the plural subjects or the single subject. The controller  201  repeatedly performs these operations. 
     When it is determined that the detected shadow of the flight apparatus  100  does not overlap with the plural subjects or the single subject (NO at step S 605 ), similarly to the process at step S 406  of  FIG. 4  in the first embodiment of the invention, the controller  201  instructs the camera system  202  to make the camera  102  image the plural subjects or the single subject from the current position (step S 407 ). Then, the controller  201  finishes the image pickup operation controlling process in the second embodiment of the invention. 
     With availability of the autonomous control of the flight apparatus  100  based on the operation of the controller  201  in the second embodiment described above, simply throwing the flight apparatus  100  in the air, the user can make the camera  102  of the flight apparatus  100  image the plural subjects belonging to the subject group or the single subject in a simple manner, while avoiding an influence of the shadow of the flight apparatus  100 . 
     A modification may be made to the disclosed second embodiment, in which the controller  201  of the flight apparatus  100  moves the flight apparatus  100  to a position, at which the shadow of the flight apparatus  100  does not overlap with at least one subject belonging to the plural subjects or the single subject and a back light imaging is not allowed, and then makes the camera  102  and the camera system  202  perform the image pickup operation at the position. 
     Third Embodiment of the Invention 
       FIG. 7  is a view for explaining a third embodiment of the invention, in which the flying flight apparatus  100  and a subject group including plural subjects are illustrated.  FIG. 8  is a flow chart of the image pickup operation controlling process performed by the flight apparatus  100  according to the third embodiment of the invention. Similarly to the process of  FIG. 4  in the first embodiment, the image pickup operation controlling process is realized by the built-in CPU of the controller  201  of  FIG. 2 , when the control program stored in the memory (not shown) built in the controller  201  is executed by the CPU. 
     In the third embodiment of the invention, the controller  201  of the flight apparatus  100  moves the flight apparatus  100  to a position, at which another subject of the plural subjects does not overlap with a face of at lest one of the plural subjects, as shown in  FIG. 7 , and makes the camera  102  and the camera system  202  perform the image pickup operation at the position. 
     The operation of the controller  201  in the third embodiment of the invention is specifically described with reference to the flow chart of  FIG. 8 . The controller  201  repeatedly judges whether the flight apparatus  100  has left the hand of the user or whether the flight apparatus has been thrown by the user (step S 801  in  FIG. 8 ), similarly to the process at step S 401  of  FIG. 4  in the first embodiment of the invention. 
     When it is determined that the flight apparatus  100  has left the hand of the user or the flight apparatus  100  has been thrown by the user (YES at step S 801 ), the controller  201  controls the motor drivers (# 1  to # 4 )  205  to drive the motors (# 1  to # 4 )  104  and rotor blades  103 , thereby making the flight apparatus  100  fly through the air to detect the subject group as shown in  FIG. 7  (step S 802 ). 
     More specifically, similarly to the process at step S 602  of  FIG. 6  in the second embodiment, the controller  201 , for example, performs the face recognition process on the image data obtained by the camera  102  and the camera system  202  to recognize the faces of the plural subjects. Then, the controller  201  detects the subject group. Further, similarly to the first embodiment of the invention, once having confirmed a state in which the subject group remains still, the controller  201 , for example, repeatedly performs the face recognition process on the image data to continuously capture the faces of the plural subjects. 
     When the flight apparatus  100  flies through the air to detect the subject group (step S 802 ), the controller  201  judges whether the subject group has been detected satisfactorily (step S 803 ). 
     When it is determined that the subject group has not been detected (NO at step S 803 ), the controller  201  returns to the process of step S 802  and tries to detect the subject group, again. 
     When it is determined that the subject group has been detected (YES at step S 803 ), the controller  201 , for example, detects an outline of the face of the subject recognized in the face recognition process which has been performed at step S 802  on the image data obtained by the camera  102  and the camera system  202 . Then, the controller  201  judges whether any subject whose outline of the face is deficient is included in the subject group, thereby determining whether plural subjects in the subject group overlap each other (step S 804 ). 
     When it is determined that the plural subjects in the subject group overlap each other (YES at step S 804 ), similarly to the process at step S 606  in  FIG. 6  in the second embodiment, while keeping capturing the subject group, the controller  201  controls the motor drivers (# 1  to # 4 )  205  to drive the motors (# 1  to # 4 )  104  and rotor blades  103 , thereby making the flight apparatus  100  fly through the air, for example, for a fixed distance in a random direction (step S 805 ). 
     Thereafter, the controller  201  returns to the process of step S 804 , and judges whether the plural subjects in the subject group overlap each other, again. 
     When it is determined that the plural subjects in the subject group do not overlap each other (NO at step S 804 ), similarly to the process at step S 406  of  FIG. 4  in the first embodiment of the invention, the controller  201  instructs the camera system  202  to make the camera  102  image the subject group from the current position (step S 806 ). Then, the controller finishes the image pickup operation controlling process in the third embodiment of the invention. 
     With availability of the autonomous control of the flight apparatus  100  based on the operation of the controller  201  in the third embodiment of the invention described above, simply throwing the flight apparatus  100  in the air, the user can make the camera  102  of the flight apparatus  100  image the plural subjects belonging to the line of the subject group without any faces of the plural subjects overlapping each other. 
     Fourth Embodiment of the Invention 
       FIG. 9  is a view for explaining a fourth embodiment of the invention, in which the flying flight apparatus  100  and a target subject group and another subject group are illustrated, both groups including plural subjects.  FIG. 10  is a flow chart of the image pickup operation controlling process performed by the flight apparatus  100  according to the fourth embodiment of the invention. Similarly to the process in  FIG. 4  in the first embodiment, the image pickup operation controlling process is realized by the built-in CPU of the controller  201  in  FIG. 2 , when the control program is executed by the CPU, stored in the memory (not shown) built in the controller  201 . 
     In the fourth embodiment of the invention, the controller  201  of the flight apparatus  100  moves the flight apparatus  100  to a position, at which another subject belonging to the another subject group does not overlap with at least one subject belonging to the target subject group or a single subject, or a position, at which another plural subjects belonging to the another subject group do not overlap with the at least one subject belonging to the target subject group or the single subject as shown in  FIG. 9 , and makes the camera  102  and the camera system  202  perform the image pickup operation at the position. 
     The operation of the controller  201  in the fourth embodiment of the invention is specifically described with reference to a flow chart in  FIG. 10 . The controller  201  repeatedly judges whether the flight apparatus  100  has left the hand of the user or whether the flight apparatus  100  has been thrown by the user (step S 1001  in  FIG. 10 ) similarly to the process at step S 401  in  FIG. 4  in the first embodiment of the invention. 
     When it is determined that the flight apparatus  100  has left the hand of the user or the flight apparatus  100  has been thrown by the user (YES at step S 1001 ), the controller  201  controls the motor drivers (# 1  to # 4 )  205  to drive the motors (# 1  to # 4 )  104  and rotor blades  103  to make the flight apparatus  100  fly through the air to detect the target subject group as shown in  FIG. 9  (step S 1002 ). 
     More specifically, similarly to the process at step S 602  in  FIG. 6  in the second embodiment, the controller  201 , for example, performs the face recognition process on image data obtained by the camera  102  and the camera system  202  to recognize the faces of the plural subjects. Then, the controller  201  detects the target subject group. A built-in receiver of the controller  201  receives a signal sent from a smart phone used by the at least one subject belonging to the subject group to detect the target subject group. Further, similarly to the first embodiment, once having confirmed a state in which the subject group remains still, the controller  201 , for example, repeatedly performs the face recognition process on the image data to continuously capture the faces of the plural subjects of the target subject group. 
     When the flight apparatus  100  flies through the air to detect the target subject group (step S 1002 ), the controller  201  judges whether the target subject group has been detected satisfactorily (step S 1003 ). 
     When it is determined that the target subject group has not been detected (NO at step S 1003 ), the controller  201  returns to the process of step S 1002  and tries to detect the target subject group, again. 
     When it is determined that the target subject group has been detected (YES at step S 1003 ), the controller  201  controls the motor drivers (# 1  to # 4 )  205  to drive the motors (# 1  to # 4 )  104  and rotor blades  103 , thereby making the flight apparatus  100  hover at the current position. Then, the controller  201  performs the face recognition process on the image data output from the camera system  202  to detect the another subject not belonging to the target subject group or the another plural subjects not belonging to the target subject group (step S 1004 ). 
     The controller  201  judges whether the another subject not belonging to the target subject group or the another plural subjects not belonging to the target subject group detected at step  1004  overlaps the target subject group detected at steps S 1002  and  1003  or the single subject, or whether the target subject group detected at steps S 1002  and  1003  or the single subject overlaps the another subject not belonging to the target subject group or the another plural subjects not belonging to the target subject group detected at step  1004  (step S 1005 ). 
     When it is determined YES at step  1005 , similarly to the process at step S 606  in  FIG. 6  in the second embodiment, while keeping capturing the target subject group, the controller  201  controls the motor drivers (# 1  to # 4 )  205  to drive the motors (# 1  to # 4 )  104  and rotor blades  103 , thereby making the flight apparatus  100  fly through the air, for example, for a fixed distance in a random direction (step S 1006 ). 
     Thereafter, the controller  201  returns to the process of step S 1004 , and detects the another subject not belonging to the target subject group or the another plural subjects not belonging to the target subject group, again, and then performs the overlapping judgment of step S 1005 , again. 
     When it is determined that the subject groups or the subjects do not overlap each other (NO at step S 1005 ), similarly to the process at step S 406  in  FIG. 4  in the first embodiment of the invention, the controller  201  instructs the camera system  202  to make the camera  102  image the target subject group from the current position (step S 1007 ). Then, the controller finishes the image pickup operation controlling process in the fourth embodiment of the invention. 
     With availability of the autonomous control of the flight apparatus  100  based on the operation of the controller in the fourth embodiment of the invention described above, simply throwing the flight apparatus  100  in the air, the user can make the camera  102  of the flight apparatus  100  image the plural subjects belonging to the line of the target subject group or the single subject without being overlapped by the another subject not belonging to the target subject group or the another plural subjects not belonging to the target subject group in a simple manner. 
     Fifth Embodiment of the Invention 
       FIG. 11  is a flow chart of the imaging controlling operation process performed by the flight apparatus  100  according to a fifth embodiment of the invention. For instance when the image pickup operation is performed in the night, it is possible to confirm a position of the flight apparatus  100  of a drone-type by making a light source of the flight apparatus  100  flash, whereby the user can determine to which direction the flight apparatus  100  should be turned. In this case, when the flight apparatus  100  of the drone-type image the plural subjects or the single subject in the night while another drone-type flight apparatus is flashing light, the flight apparatus  100  is moved to a position, at which the light of the another drone-type flight apparatus does not overlap with the plural subjects or the single subject, and the camera  102  and the camera system  202  are made to perform the image pickup operation at the position. 
     The operation of the controller  201  in the fifth embodiment of the invention is specifically described with reference to the flow chart in  FIG. 11 . The controller  201  repeatedly judges whether the flight apparatus  100  has left the hand of the user or whether the flight apparatus  100  has been thrown by the user (step S 1101  in  FIG. 11 ), similarly to the process at step S 401  in  FIG. 6  in the first embodiment of the invention. 
     When it is determined that the flight apparatus  100  has left the hand of the user or the flight apparatus  100  has been thrown by the user (YES at step S 1101 ), the controller  201  controls the motor drivers (# 1  to # 4 )  205  to drive the motors (# 1  to # 4 )  104  and rotor blades  103 , thereby making the flight apparatus  100  fly through the air to detect the plural subjects or the single subject as shown in  FIG. 10  (step S 1102 ). 
     More specifically, similarly to the process at step S 602  in  FIG. 6  in the second embodiment, the controller  201 , for example, performs the face recognition process on image data obtained by the camera  102  and the camera system  202 , thereby recognizing faces of the plural subjects or a face of the single subject. Then, the controller  201  detects the plural subjects or the single subject. Similar to the process at step S 1002  in  FIG. 10  in the fourth embodiment, the built-in receiver of the controller  201  receives the signal sent from the smart phone used by the at least one subject belonging to the plural subjects or the signal sent from the smart phone used by the single subject to detect the plural subjects or the single subject. Further, similar to the first embodiment, once having confirmed a state in which the plural subjects or the single subject remains still, the controller  201 , for example, repeatedly performs the face recognition process on the image data to continuously capture the faces of the plural subjects in the subject group or the face of the single subject. 
     When the flight apparatus  100  flies through the air to detect the plural subjects or the single subject (step S 1102 ), the controller  201  judges whether the plural subjects or the single subject has been detected satisfactorily (step S 1103 ). 
     When it is determined that the plural subjects or the single subject has not been detected (NO at step S 1103 ), the controller  201  returns to the process of step S 1102  and tries to detect the plural subjects or the single subject, again. 
     When it is determined that the plural subjects or the single subject has been detected (YES at step S 1103 ), the controller  201  controls the motor drivers (# 1  to # 4 )  205  to drive the motors (# 1  to # 4 )  104  and rotor blades  103 , thereby making the flight apparatus  100  hover at the current position. Then, the controller  201  detects the light emitted from another flight apparatus, while hovering at the current position (step S 1104 ). More particularly, the controller  201  detects a light temporally moving in the air as the light to be detected. 
     The controller  201  judges whether the light detected at step S 1104  overlaps with the plural subjects or the single subject detected at steps S 1102  and S 1103  (step S 1105 ). 
     When it is determined that the light overlaps with the plural subjects or the single subject (YES at step S 1105 ), similar to the process at step S 606  in  FIG. 6  in the second embodiment, while keeping capturing the plural subjects or the single subject, the controller  201  controls the motor drivers (# 1  to # 4 )  205  to drive the motors (# 1  to # 4 )  104  and rotor blades  103 , thereby making the flight apparatus  100  fly through the air, for example, for a fixed distance in a random direction (step S 1106 ). 
     Thereafter, the controller  201  returns to the process of step S 1104 , and detects the light and judges at step S 1105  whether the light overlaps with the plural subjects or the single subject, again. 
     When it is determined that the light does not overlap with the plural subjects or the single subject (NO at step S 1105 ), similarly to the process at step S 406  in  FIG. 4  in the first embodiment of the invention, the controller  201  instructs the camera system  202  to make the camera  102  image the plural subjects or the single subject from the current position (step S 1107 ). Then, the controller finishes the image pickup operation controlling process in the fifth embodiment of the invention. 
     With availability of the autonomous control of the flight apparatus  100  based on the operation of the controller  201  in the fifth embodiment of the invention described above, simply throwing the flight apparatus  100  in the air, the user can make the camera  102  of the flight apparatus  100  image the plural subjects belonging to the line of the subject group or the single subject in a simple manner while avoiding an influence of the light of the another flight apparatus. 
     Sixth Embodiment of the Invention 
       FIG. 12  is a flow chart of the imaging controlling operation process performed by the flight apparatus  100  according to a sixth embodiment of the invention. In the sixth embodiment, the imaging controlling operation process is performed by the flight apparatus  100  of a drone-type, when the imaging operation is performed to image a subject group or a single subject in the night, similar to the imaging operation in the fifth embodiment, while another drone-type flight apparatus is flashing light. 
     In the sixth embodiment of the invention, when the another drone-type flight apparatus is flashing the light, the flight apparatus  100  sends a request to the another flight apparatus, asking to stop flashing light for a predetermined period, and instructs the camera  102  and the camera system  202  to perform the image pickup operation. 
     In the flow chart of  FIG. 12  in the sixth embodiment, the controller  201  performs the same processes (S 1101  to S 1107 ) as those given the same step numbers as the processes in the flow chart of  FIG. 11 . 
     The process at step S 1201  in the flow chart of  FIG. 12  in the sixth embodiment is different from the processes in the flow chart of  FIG. 11  in the fifth embodiment. At the process of step S 1201 , the controller  201  sends a request to the another flight apparatus to turn off the light temporarily in place of moving away, when it has been determined that the light overlaps with the plural subjects or the single subject (step S 1105 ). 
     As a result, having confirmed that the another flight apparatus has turned off the light and the light does not overlap with the plural subjects or the single subject (NO at step S 1105 ), the controller  201  instructs the camera  102  and the camera system  202  to perform the image pickup operation. 
     With availability of the autonomous control of the flight apparatus  100  based on the operation of the controller in the fifth embodiment of the invention described above, simply throwing the flight apparatus  100  in the air, the user can make the camera  102  of the flight apparatus  100  image the plural subjects belonging to the line of the subject group or the single subject while avoiding an influence of the light of the another flight apparatus. 
     In the respective embodiments of the invention, the plural subjects or the single subject can be imaged in a simple manner as described above. 
     Modifications 
     In the above description, the invention has been described taking as an example the flight apparatus of the drone type, having the propulsion unit for flying through the air, but the invention is not restricted to the flight apparatus. The present invention, for example, can be applied to a robot having a propulsion member for proceeding on the ground. 
     Further, in the above respective embodiments of the invention, the simple face recognizing process is applied and performed on the image data to capture the plural subjects belonging to the subject group or the single subject but it is possible to recognize smiling faces to capture the plural subjects belonging to the subject group or the single subject. 
     In the above described embodiments of the invention, it is possible for the user to use a switch to select the process to be performed. 
     In the above described embodiments of the invention, the flight apparatus  100  is allowed to perform the imaging operation, thereby obtaining any number of still images. The flight apparatus  100  can obtain not only still images but also moving images of an arbitrary time. 
     In the above described embodiments of the invention, the flight apparatus  100  has the propulsion unit including the motors  104  and rotor blades  103 . But a propulsion unit using compressed air and/or an engine can be used in place of the propulsion unit including the motors  104  and rotor blades  103 . 
     In the above described embodiments of the invention, a relationship between the plural subjects and the operator of the imaging apparatus  100  or a relationship between the single subject and the operator of the imaging apparatus  100  has not been explained. It is possible that the operator is included in the plural subjects or the operator is the single subject. 
     In the above described embodiments of the invention, the controlling unit controls the propulsion unit to move the flight apparatus such that the at least two out of the plural subjects and the image pickup unit do not interfere in position with each other, or such that the single subject and the image pickup unit do not interfere in position with each other, thereby allowing the image pickup unit to image the plural subjects or the single subject. But an image pickup timing is not restricted to the previously described timing. 
     Although specific embodiments of the invention have been described in the foregoing detailed description, it will be understood that the invention is not limited to the particular embodiments described herein, but modifications and rearrangements may be made to the disclosed embodiments while remaining within the scope of the invention as defined by the following claims. It is intended to include all such modifications and rearrangements in the following claims and their equivalents.