JP2019109776A - Moving body - Google Patents

Abstract

To avoid such a problem that in a moving body that performs positioning using a photographed marker, if photographing of an inappropriate exposure is performed in a backlight state or the like, the marker cannot be detected in the photographed image.SOLUTION: A moving body 1 that moves autonomously comprises: a photographing unit 12 for acquiring a photographed image of a marker; a position acquisition unit 14 for acquiring a position of the moving body 1 using the marker recognized in the photographed image; a movement mechanism 11 for moving the moving body 1; a movement control unit 16 for controlling the movement mechanism 11 using the acquired position; and a photographing control unit 13 for controlling the photographing unit 12 to acquire photographed images with different exposures, wherein the position acquisition unit 14 acquires a position using a captured image that does not cause an error. In this way, it becomes possible to acquire a photographed image of a marker photographed at a proper exposure, and appropriate positioning can be performed using the photographed marker.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a mobile that moves autonomously.

  In a conventional moving body, a marker placed in a moving environment may be photographed, and the marker may be positioned by using the photographed marker. In such a mobile, it may be possible to get backlit when shooting a marker. For example, in a situation where a shutter or window is present behind a marker placed in a mobile environment, the shutter or the blind is usually closed so that it does not back light when the marker is shot, but it is possible When the shutter, blind, etc. are opened due to reasons, it may be backlit. In such a case, there is a problem that the marker can not be properly recognized due to overexposure or the like in the captured image, and positioning using the marker can not be performed.

  In addition, as related technology, even when imaging in a backlit state, there is known a crop row detection device that performs appropriate exposure adjustment using information on the light amount detected by the light amount detection unit (see Patent Document 1). ).

Unexamined-Japanese-Patent No. 5-265545

  However, in the technique described in Patent Document 1, it is necessary to separately provide a light amount detection unit to perform exposure correction, and accordingly, there is a problem that the apparatus becomes complicated and the cost increases.

  The present invention has been made to solve the above-described problems, and has an object of providing a moving body capable of appropriately photographing a marker used for positioning with a simple configuration.

In order to achieve the above object, a mobile according to the present invention is a mobile that moves autonomously, and a position of the mobile using an imaging unit for acquiring a captured image of a marker and a marker recognized in the captured image. Using a position acquisition unit for acquiring the image, a movement mechanism for moving the movable body, and a movement control unit for controlling the movement mechanism using the position acquired by the position acquisition unit, and photographing so as to acquire photographed images with different exposures And a position acquisition unit for acquiring the position of the moving object using the photographed image that does not cause an error.
With such a configuration, it is possible to acquire a photographed image of a marker photographed at an appropriate exposure by control of acquiring photographed images having different exposures, and performing appropriate positioning by using the photographed image. become able to. In addition, since it is not necessary to provide a light amount detection unit for exposure correction, acquisition of such a photographed image can be realized with a simple configuration without increasing the cost.

In the mobile object according to the present invention, the photographing control unit may cause the photographing unit to acquire a photographed image whose exposure is different from that of the photographed image, when a certain photographed image becomes an error.
With such a configuration, it is not always necessary to store a large number of captured images at one time in order to determine whether an error occurs at each imaging. Therefore, for example, the capacity of the recording medium for storing the photographed image can be reduced. In addition, when the appropriate exposure is achieved by the small number of times of capturing, acquisition of the position using the marker can be realized in a shorter time.

Further, in the moving object according to the present invention, the photographing control unit may change the exposure of the newly acquired photographed image as previously determined.
With such a configuration, for example, it is possible to obtain a captured image such that the exposure gradually changes from under to over or from over to under each time shooting is repeated. At the stage, it is possible to obtain a photographed image of the proper exposure for the marker.

In addition, in the moving object according to the present invention, the photographing control unit may change the exposure of the newly acquired photographed image using the luminance of the already acquired photographed image.
With such a configuration, it is possible to acquire a photographed image of the proper exposure with a smaller number of photographing times as compared with the case where the exposure of a new photographed image is changed, as previously determined.

Further, in the moving object according to the present invention, the imaging control unit may change the exposure of the newly acquired captured image using the entire luminance value of the acquired captured image.
With such a configuration, it is possible to determine the appropriate exposure of the newly acquired captured image even when the position of the marker in the captured image changes significantly for each positioning of the moving object using the marker. Become.

Further, in the moving object according to the present invention, the photographing control unit may change the exposure of the newly acquired photographed image using the luminance value of the predetermined part of the acquired photographed image.
With such a configuration, it is possible to determine the appropriate exposure of the newly acquired captured image with higher accuracy when the position of the marker in the captured image does not change much for each positioning of the moving object using the marker. become.

Further, in the moving object according to the present invention, the photographing control unit controls the photographing unit to acquire a plurality of photographed images having different exposures, and the position acquiring unit does not cause an error among the plurality of acquired photographed images. The position of the moving object may be acquired using a captured image.
With such a configuration, it is not necessary to repeat acquisition of a captured image, determination of whether or not it is an error, and re-imaging in the case of an error in order to obtain a captured image of a proper exposure.

Further, in the moving object according to the present invention, the imaging control unit causes the imaging unit to acquire a captured image when the positional relationship between the marker and the moving object is determined in advance, and the position acquisition unit An error may be generated if the recognized marker deviates from a predetermined one by more than a threshold.
With such a configuration, error determination can be performed by simple image processing.

Further, the moving object according to the present invention further includes a current position obtaining unit that obtains the current position of the moving object without using a marker, and the position obtaining unit obtains the position obtained using the marker recognized in the captured image; An error may be generated if the position acquired by the current position acquisition unit differs from the position by a threshold value.
With such a configuration, it is possible to determine whether or not an error occurs even in a situation where the positional relationship between the moving object and the marker at the time of shooting the marker is not constant.

  According to the moving body according to the present invention, the marker used for positioning can be appropriately photographed with a simple configuration.

Block diagram showing the configuration of a mobile according to an embodiment of the present invention Flowchart showing an example of the operation of the mobile according to the same embodiment Flowchart showing another example of the operation of the mobile according to the embodiment A schematic view showing the arranged marker and the moving body in the same embodiment A schematic view showing the arranged marker and the moving body in the same embodiment A diagram for explaining recognition of a marker in the same embodiment The figure which shows an example of the picked-up image in the embodiment

  Hereinafter, the mobile unit according to the present invention will be described using the embodiment. In the following embodiments, components and steps denoted by the same reference numerals are the same or correspond to each other, and the description thereof may not be repeated. The moving body according to the present embodiment is a moving body that acquires a position by imaging a marker, acquires captured images with different exposures, and acquires a position using a captured image that does not cause an error.

  FIG. 1 is a block diagram showing the configuration of a mobile unit 1 according to the present embodiment. The movable body 1 according to the present embodiment moves autonomously, and the movement mechanism 11, the imaging unit 12, the imaging control unit 13, the position acquisition unit 14, the current position acquisition unit 15, and movement control And a unit 16. Note that moving the mobile unit 1 autonomously may be moving to a destination based on its own judgment instead of moving according to an operation instruction that the mobile unit 1 receives from a user or the like. The destination may be, for example, manually determined or automatically determined. Also, the movement to the destination may or may not be performed, for example, along the movement path. Further, to move to the destination based on its own judgment may be, for example, moving to the destination by the moving body 1 determining itself by the traveling direction, movement, stop, and the like. Also, for example, the mobile unit 1 may move so as not to collide with an obstacle. The moving body 1 may be, for example, a carriage or a moving robot. The robot may be, for example, an entertainment robot, a monitoring robot, a transfer robot, a cleaning robot, or a robot for capturing a moving image or a still image. , May be other robots.

  The moving mechanism 11 moves the moving body 1. For example, the moving mechanism 11 may or may not be capable of moving the moving body 1 in all directions. To be able to move in all directions means to be able to move in any direction. The moving mechanism 11 may have, for example, a traveling unit (for example, a wheel or the like) and a driving unit (for example, a motor or an engine) for driving the traveling unit. When the moving mechanism 11 can move the moving body 1 in all directions, the traveling part may be an all-direction moving wheel (for example, an omni wheel, a mecanum wheel, or the like). For a movable body having an omnidirectionally moving wheel and movable in all directions, see, for example, JP-A-2017-128187. A known mechanism can be used as the moving mechanism 11, and thus the detailed description thereof is omitted.

  The imaging unit 12 captures a marker present in the mobile environment to acquire a captured image. The imaging unit 12 can be realized by, for example, an image sensor such as a CCD or a CMOS. In addition, the imaging unit 12 may include an optical system for forming light from an imaging target on the light receiving surface of the image sensor. Further, the data format of the photographed image is not limited. Since the imaging unit 12 is fixed to the mobile unit 1, the imaging target is different according to the movement of the mobile unit 1. Therefore, when the imaging unit 12 continuously performs imaging and a marker is included in the imaging range, the captured image including the marker may be used by the position acquisition unit 14 or the like, or from the imaging control unit 13 When a photographing instruction of is received, a photographed image including a marker may be acquired. Note that whether or not a marker is included in the imaging range may be performed by, for example, pattern matching of markers, or may be performed by another method. FIG. 4A is a schematic view showing a situation in which the marker 5 is photographed by the photographing unit 12 of the movable body 1. As shown in FIG. 4A, the presence of the marker 5 in the imaging range of the imaging unit 12 enables the imaging unit 12 to acquire a captured image of the marker 5. Further, the photographing unit 12 acquires photographed images with different exposures according to the control by the photographing control unit 13. The control will be described later. Here, as a method of changing the exposure of a captured image, there are, for example, a method of changing an exposure time (shutter speed), a method of changing an aperture value (F value), and a method of changing both of them. In the present embodiment, the case of changing the exposure by changing the exposure time will be mainly described.

  The marker is a visually recognizable two-dimensional figure, and is disposed in a moving environment for positioning the moving body 1. For example, a marker may be disposed to enable the mobile unit 1 to accurately move to the feeding position or the unloading position of the transport target. The shape of the marker (the shape of the figure) is not limited, but for example, it may be square, rectangular, other polygonal shapes, circular shapes, elliptical shapes, or a combination thereof. Preferably, the shape has three or more identifiable feature points. In addition, it is preferable that the size between feature points is known for at least three of the feature points. Since the size is necessary to acquire the relative positional relationship between the marker and the imaging unit 12, the size is held in a recording medium (not shown) of the movable body 1, and can be accessed by the position acquisition unit 14 etc. It is preferable that The marker is, for example, printed on paper, film or the like and placed in a mobile environment. The position in the world coordinate system of the marker placed in the moving environment of the moving body 1 (for example, the relative relationship between the world coordinate system and the coordinate system of the marker (information on translation and rotation) may be used). It may or may not be known. In the former case, the position of the moving body 1 in the world coordinate system can be obtained by using the photographed image of the marker, and in the latter case, the movement is performed by using the photographed image of the marker It becomes possible to obtain the position of the body 1 relative to the marker. Therefore, when the position of the marker in the world coordinate system is not known, positioning is performed according to the relative position to the marker placed in the moving environment. Preferably, the markers are arranged to have a predetermined relative position.

  The imaging control unit 13 controls the imaging unit 12 to acquire captured images with different exposures. For example, the imaging control unit 13 may cause the imaging unit 12 to continuously acquire captured images, and when the positional relationship between the marker and the moving object 1 is determined in advance, the imaging unit 12 may use the captured image. You may get In the former case, as described above, since the captured image not including the marker is also acquired, it may be determined by pattern matching or the like whether or not the marker is included in the captured image. Also, in the case where the imaging timing is such that the positional relationship between the marker and the moving object 1 is determined in advance, the moving object 1 with respect to the marker is acquired using, for example, the current position acquired by the current position acquiring unit 15 When it is determined that the position of (this position may include an angle) has become a predetermined one, imaging may be performed. Specifically, when the imaging unit 12 of the moving body 1 is in a position where the marker can be imaged directly from the front, the imaging control unit 13 may control the imaging unit 12 to perform imaging.

  As a method of controlling the photographing unit 12 so as to obtain photographed images different in exposure, the photographing control unit 13 controls the photographing to be performed with different exposure (1) when an error occurs, (2 ) A method of controlling so as to take a plurality of shots with different exposures in advance will be described.

(1) A method of controlling to shoot with different exposure when an error occurs When the shooting control unit 13 causes an error in a shot image, the shooting unit takes a shot image having a different exposure from the shot image. You may make it acquire to 12. An error in a captured image means that the captured image can not be used to obtain an appropriate position. As a cause of the captured image becoming an error, for example, the marker can not be recognized in the captured image, or the marker is misrecognized in the captured image. In the case of (1), the photographing control unit 13 may cause the photographing unit 12 to repeat acquisition of a photographed image until no error occurs. In addition, even if photographing of a predetermined upper limit number is performed, when the photographed image which is not an error can not be acquired, the photographing control unit 13 determines that an abnormality has occurred, and stops this control. Good.

  In the change of the exposure, the imaging control unit 13 may change the exposure of the newly acquired captured image as (A) determined in advance, and (B) uses the luminance of the acquired captured image. The exposure of the newly acquired captured image may be changed. Each of (A) and (B) will be described below.

(A) Method of Changing Exposure of Newly Photographed Image As Predetermined In this case, for example, the photographing control unit 13 sets the exposure to the over side every time photographing is repeated (photographed image The exposure may be changed, or the exposure may be changed so that the exposure is on the underside each time the shooting is repeated (the captured image becomes dark), and other rules You may change the exposure with.

  Specifically, the imaging control unit 13 causes the first captured image to be captured in 1/2000 sec, and when an error occurs, causes the next captured image to be captured in 1/1000 sec, and the error is generated again. In this case, 1/250 second, 1/125 second, 1/60 second, 1 until the next shot image is taken in 1/500 seconds, etc. until the shot image without error is acquired. The exposure change may be repeated for each shooting, such as / 30 seconds, 1/15 seconds, 1/8 seconds, and 1/4 seconds. In this case, the exposure is changed to the over side. Conversely, the shooting control unit 13 causes the first shot image to be shot in 1⁄4 second, and when an error occurs, causes the next shot image to be shot in 1⁄8 second, etc. The exposure may be changed to the under side one by one until the captured image without error is acquired.

(B) Method of changing the exposure of a new captured image using the luminance of the acquired captured image In this case, the imaging control unit 13 uses, for example, the entire luminance value of the acquired captured image. The exposure of the newly acquired captured image may be changed, or the exposure of the newly acquired captured image may be changed using the luminance value of the predetermined part of the already acquired captured image. As a specific changing method, the luminance value of the entire acquired image or at a predetermined position is compared with a predetermined threshold, and if the luminance value of the acquired image is larger than the threshold, a new value is obtained. The exposure of the captured image may be changed to the underside, and when the luminance value of the acquired captured image is smaller than the threshold, the exposure of the new captured image may be changed to the overside. The acquired captured image may be the latest captured image (that is, the captured image acquired last) among the acquired captured images. In addition, if the imaging of the marker is performed when the positional relationship between the marker and the moving object 1 is predetermined, the position of the marker in the captured image is generally fixed. FIG. 6 is a view showing an example of such a photographed image. The photographed image 21 shown in FIG. 6 includes the marker 5 displayed on the display plate 7. For example, even if the position of the marker 5 in the photographed image 21 fluctuates for each photographing, if it is substantially within the range of the area 22, the photographing control unit 13 uses the luminance value of the area 22 in the photographed image 21 The exposure of the newly acquired captured image may be determined. By doing so, the exposure can be determined more properly. Also, when comparing the luminance value of the entire acquired image or at a predetermined location with a predetermined threshold, the representative value of the luminance value of the entire imaged image or the predetermined location is compared with the predetermined threshold. You may The representative value may be, for example, an average value or an intermediate value. In addition, when comparing the luminance value of a predetermined part of a captured image with a predetermined threshold, the representative value may be a maximum value or a minimum value. When changing the exposure to the under side, the photographing control unit 13 changes, for example, the shutter speed to one step and to the faster side, and when changing the exposure to the over side, for example, the shutter speed to one step. You may change to the later one. Specifically, when the shutter speed of the acquired captured image is 1/1000 sec and the exposure is changed to the under side, the shutter speed of the new captured image may be set to 1/2000 sec. Good.

(2) Method of Controlling Multiple Exposures with Different Exposures in advance The imaging control unit 13 may control the imaging unit 12 to acquire a plurality of captured images with different exposures. In this case, photographed images are acquired in advance with a plurality of exposures, and among these, the position is acquired using the photographed images that do not cause an error. For example, the imaging control unit 13 may be configured to capture 1/2000 sec, 1/1000 sec, 1/500 sec, 1/250 sec, 1/125 sec, 1/60 sec, 1/30 sec, 1/15 sec, and 1/00. The photographing unit 12 may be controlled to acquire a photographed image at each shutter speed of 8 seconds and 1⁄4 second. In this case, ten photographed images are acquired at one time, and among the ten photographed images, one that does not cause an error is used for acquiring the position.

  The position acquisition unit 14 acquires the position of the mobile body 1 using the marker recognized in the captured image. The position may be a position relative to the marker or may be a position in the world coordinate system. Here, what the position acquisition unit 14 can obtain directly using the photographed image of the marker is the relative position of the moving body 1 to the marker (for example, the position of the moving body 1 in the marker coordinate system, etc.) It is. On the other hand, when the position of the marker in the world coordinate system is known, the position acquisition unit 14 uses the relative position of the marker and the position of the marker in the world coordinate system in the world coordinate system of the moving body 1. It will be possible to get the position. The position acquired by the position acquisition unit 14 may not include the angle (posture), or may include the angle. The angle may be an angle relative to the plane of the marker or an angle in the world coordinate system. In the present embodiment, a case where an angle is also included in the position acquired by the position acquisition unit 14 will be mainly described. The specific method of acquiring the position will be described later.

  The position acquisition unit 14 acquires the position of the moving object 1 using a captured image that does not cause an error. When shooting is performed as described in (1) above, acquisition of a photographed image is repeated until an error does not occur, so the position acquisition unit 14 acquires a photographed image that is not an error acquired in this way. The position of the mobile unit 1 is acquired using this. That is, the position acquisition unit 14 may acquire the position using the first captured image that did not cause an error. Also, when shooting is performed as described in (2) above, the position acquisition unit 14 acquires the position of the mobile body 1 using a photographed image that does not cause an error among a plurality of acquired photographed images. .

  The determination of whether or not the photographed image is an error is performed by the position acquisition unit 14. For example, when the imaging unit 12 acquires a captured image when the positional relationship between the marker and the moving object 1 is determined in advance, the position acquiring unit 14 determines that the marker recognized in the captured image is defined. An error may be generated when the marker and the threshold are deviated beyond each other. In the case where the imaging unit 12 acquires a captured image when the positional relationship between the marker and the moving object 1 is predetermined, the marker is normally present at a predetermined position each time in the captured image. Become. It is assumed that a marker present at the predetermined position is registered as a prescribed marker. Therefore, when the marker (prescribed marker) at the predetermined position is deviated beyond the threshold value, shooting is performed with an exposure that makes the recognition of the marker inappropriate. The acquisition unit 14 determines that an error occurs. The error determination will be specifically described with reference to FIG. FIG. 5A shows a marker 5 (this marker is referred to as “a marker at an ideal position”) included in a captured image captured when the positional relationship between the marker and the moving object 1 is predetermined. 5 (b) shows the marker 6 properly recognized in the photographed image, and FIG. 5 (c) shows the marker 5 at the ideal position, It is a figure which shows the marker 6 recognized by mistake. When a photographed image is obtained with the proper exposure, it is correctly recognized as shown by the marker 6 shown in FIG. 5 (b). On the other hand, for example, when the exposure is over and the right side of the marker 5 is white-out, it is erroneously recognized as the marker 6 shown in FIG. 5C. In such a case, the position acquisition unit 14 may determine whether there is an error according to the deviation of each of the markers 5 and 6. Specifically, as shown in FIG. 5A, the positions on the photographed image regarding the four vertices T1 to T4 of the marker 5 at the ideal position are registered in advance. Next, for example, the positions on the captured image regarding the four vertices T1 ′ to T4 ′ of the marker 6 recognized as shown in FIG. 5B or 5C are respectively acquired. Then, the distance between T1 and T1 ′, the distance between T2 and T2 ′, the distance between T3 and T3 ′, and the distance between T4 and T4 ′ are calculated, and the representative value of the distance is compared with the threshold value, If the representative value exceeds the threshold, it may be determined that an error occurs. The representative value may be, for example, an average value or a maximum value. Here, the case of judging whether it is an error or not is described using the distance of the vertex which is the feature point of the marker, but it is judged whether or not it is an error or not using the distance of other feature points. It is also good. As feature points other than the vertex, for example, there are a center point and a center of gravity of a marker. The position acquisition unit 14 determines that an error occurs even when the distance between a feature point such as the center point or the center of gravity of the recognized marker and the feature point of the marker registered in advance exceeds a threshold. Good. In addition, here, the case where it is determined whether or not the marker recognized in the captured image deviates from the specified marker by more than the threshold from the distance of the feature point of the marker has been described. It goes without saying that you may For example, the determination may be made by comparing the angle of the marker recognized in the captured image with the angle of the specified marker.

  Also, for example, when the positional relationship between the marker and the moving object 1 is determined in advance, if the imaging unit 12 acquires a captured image, the position acquisition unit 14 uses the marker recognized in the captured image. An error may be generated when the relative positional relationship between the mobile body 1 and the marker acquired is deviated beyond the positional relationship registered in advance and the threshold. When imaging is performed when the positional relationship between the marker and the moving body 1 is predetermined, usually, the relative positional relationship between the moving body 1 and the marker is the same each time. Therefore, when the positional relation is registered and the positional relation deviated beyond the threshold is acquired, for example, as shown in FIG. 5C, the positional relation is recognized using the misrecognized marker. Since the captured image is acquired, the captured image may be regarded as an error.

  In addition, the position acquisition unit 14 may generate an error when the position acquired using the marker recognized in the photographed image and the position acquired by the current position acquisition unit 15 differ by more than a threshold. In this case, it is preferable that the position of the marker in the world coordinate system is known. Normally, the current position acquired by the current position acquisition unit 15 is a position in the world coordinate system, and therefore, the position acquired using the marker also needs to be the position in the world coordinate system. For example, as shown in FIG. 5C, when an incorrect marker 6 is recognized, an incorrect position will be obtained according to the marker 6. Therefore, since the difference between the incorrect position and the current position acquired by the current position acquisition unit 15 is a large value, it is possible to judge the error also by such a method.

  As a threshold used in the judgment of an error using the position of the marker in the photographed image or the judgment of an error using the current position, for example, photographing with the appropriate exposure of the marker actually using the moving object 1 By doing this, the error between the marker recognized in the photographed image and the marker at the ideal position, or the error between the position obtained using the marker and the current position is calculated, and these errors are not judged as errors. It may be set as

  Further, the position acquisition unit 14 may determine that an error occurs if the marker can not be recognized in the photographed image, for example, if the marker can not be recognized even if pattern matching or the like is performed. For example, if the entire marker is overexposed or overexposed in the captured image, the marker can not be recognized. In such a case, it may be judged as an error.

  The current position acquisition unit 15 acquires the current position of the mobile unit 1. However, it is assumed that the current position acquisition unit 15 does not use a marker, that is, acquires the current position by a method other than shooting of a marker. This is because the acquisition of the position using the marker is performed by the position acquisition unit 14. Acquisition of the current position by the current position acquisition unit 15 may be performed using, for example, wireless communication, or may be performed using a measurement result of the distance to the surrounding object, and capturing an image of the surrounding area , And may be performed using other means capable of obtaining the current position. As a method of acquiring the current position using wireless communication, for example, a method using GPS (Global Positioning System), a method using indoor GPS, a method using a nearest wireless base station, and the like are known. Also, for example, as a method of acquiring the current position by using the measurement result of the distance to the surrounding object or photographing the surrounding image, for example, known by SLAM (Simultaneous Localization and Mapping) or the like. Any method may be used. In addition, when a map (for example, a measurement result of a distance to a surrounding object, a map having a photographed image, and the like) created in advance is stored, the current position acquisition unit 15 determines the distance to the surrounding object. The current position may be obtained by measuring and using a map to specify the position corresponding to the measurement result, taking a surrounding image, and using the map to specify a position corresponding to the shooting result You may obtain the current position by doing this. Also, the current position acquisition unit 15 may acquire the current position using, for example, an autonomous navigation device. Further, it is preferable that the current position acquisition unit 15 acquire the current position including the direction (direction) of the mobile body 1. The direction may be indicated by an azimuth angle measured clockwise, for example, with 0 degrees to the north, and may be indicated by information indicating other directions. The orientation may be obtained by an electronic compass or a geomagnetic sensor.

  The position acquisition unit 14 can acquire the position only when the imaging unit 12 captures a marker. Therefore, when the mobile unit 1 is moving the location where the marker does not exist, the mobile unit 1 can not acquire the position by the position acquisition unit 14. It is preferable to have a current position acquisition unit 15 for acquiring the current position of

  The movement control unit 16 controls the movement of the movable body 1 by controlling the movement mechanism 11. The control of movement may be control of the direction of movement of the mobile body 1 or start / stop of movement. For example, when the movement path is set, the movement control unit 16 may control the movement mechanism 11 so that the moving body 1 moves along the movement path. More specifically, the movement control unit 16 may control the movement mechanism 11 so that the current position acquired by the current position acquisition unit 15 is along the movement path. In addition, the movement control unit 16 may control movement using a map. In that case, the mobile unit 1 may include a storage unit in which a map is stored.

  The movement control unit 16 also controls the movement mechanism 11 using the position acquired using the marker, that is, the position acquired by the position acquisition unit 14. The movement control unit 16 may move the movable body 1 to a predetermined position using the position acquired by the position acquisition unit 14. Specifically, the movement control unit 16 may move the moving body 1 to the power feeding position, the unloading position of the transport target, or the like according to the position acquired using the marker. Generally, the position acquired using the marker has higher accuracy than the position acquired by the current position acquisition unit 15. Therefore, the movement control unit 16 may perform the movement required with high accuracy using the position acquired using the marker. For example, the elevators may be moved in and out of the car by using markers arranged in the car of the elevator or in the elevator hall. For example, the movement control unit 16 performs movement control using the current position acquired by the current position acquisition unit 15 up to the position where the marker is present, and uses the marker after the marker is photographed by the photographing unit 12 The movement control may be performed using the position acquired. Movement control using a marker is already known, and the detailed description thereof is omitted.

Next, acquisition of a position using a marker will be described. Here, the local coordinate system of the imaging unit 12 is C _C and the local coordinate system of the marker 5 is C _M. Further, with regard to a certain point, the coordinate values of the imaging unit 12 in the coordinate system C _C are (x, y, z) = (p _x , p _y , p _z ), and the coordinate values of the marker 5 in the coordinate system C _M Assuming that x1, y1, z1) = (p _x1 , p _y1 , p _z1 ), both coordinate values are related as shown in the following equation using a homogeneous transformation matrix P _CM that transforms coordinate values between both coordinate systems. Will be T indicates transposition.
(P _x , p _y , p _z , 1) ^T = P _CM (p _x1 , p _y1 , p _z1 , 1) ^T

The homogeneous transformation matrix P _CM of the above equation includes the arguments q _x , q _y , q _z , θ, φ, 、, which are the coordinate system _C of the marker with respect to the coordinate system C _C of the imaging unit 12 _It shows the parallel displacement (q _x , q _y , q _z ) and rotation (θ, φ, ψ) of _M. As described above, assuming that the size between the three feature points of the marker is known, each argument included in the homogeneous transformation matrix P _CM is used by using the size (the distance between the feature points). It is known to be required, and the homogeneous transformation matrix P _CM can be identified. In this manner, by photographing the markers, can be calculated homogeneous transformation matrix P _CM, the relationship between the coordinate system C _M coordinate system C _C and marker 5 of the imaging unit 12, i.e., the imaging unit 12 relative to the marker 5 The relative position of can be obtained. In the local coordinate system of the mobile unit 1, the position including the orientation of the imaging unit 12 is known. Therefore, if the positional relationship between the imaging unit 12 and the marker 5 is known, the positional relationship between the moving body 1 and the marker 5 is also known. In this way, the mobile unit 1 can acquire the position of the mobile unit 1 with respect to the marker 5.

  In addition, when the position of the marker 5 in the world coordinate system is known, the moving object 1 can be obtained by using the relative positional relationship between the moving object 1 and the marker 5 and the position of the marker 5 in the world coordinate system. It goes without saying that the position in the world coordinate system of can also be obtained.

  Further, in the present embodiment, the case where the homogeneous transformation matrix is used to acquire the position using the marker has been mainly described, but this may not be the case. It goes without saying that the acquisition of the position using the marker can also be performed by a method that does not use the homogeneous transformation matrix.

Next, the operation of the mobile unit 1 will be described using the flowcharts of FIG. 2 and FIG. FIG. 2 is a flow chart showing the operation of the mobile unit 1 that controls imaging according to the method (1) above.
(Step S101) The movement control unit 16 controls the movement of the movable body 1. The control of this movement is, for example, control of autonomous movement toward the destination. By repeatedly performing the control of the movement in step S101, the mobile body 1 moves from the departure point to the destination point.

  (Step S102) The movement control unit 16 determines whether to perform positioning using a marker. And when positioning using a marker is performed, it progresses to step S103, and when that is not right, it returns to step S101. Note that, for example, when it is found that the positional relationship between the marker and the moving body 1 is determined in advance by the current position acquired by the current position acquisition unit 15, the movement control unit 16 determines It may be determined that the positioning used will be performed. Further, for example, when the photographing by the photographing unit 12 is performed even during the movement control in step S101, the movement control unit 16 detects the marker when the photographed image comes to include the marker. It may be determined that the positioning used will be performed.

  (Step S103) The photographing unit 12 acquires a photographed image of the marker by the exposure set by the photographing control unit 13. When acquiring the first photographed image, the photographing control unit 13 may set the default exposure. The acquired captured image may be stored in a storage medium (not shown).

  (Step S104) The position acquisition unit 14 acquires the position of the mobile object 1 using the captured image acquired in step S103. In the case of an error, it may be impossible to obtain the position.

  (Step S105) The position acquisition unit 14 determines whether the acquisition of the position is an error, that is, whether the acquired captured image is an error. And when it is an error, it progresses to step S106, and when that is not right, it progresses to step S107. If an error occurs even if acquisition of a captured image is repeated a predetermined number of times, the processing may be terminated on the assumption that an abnormality has occurred.

  (Step S106) The photographing control unit 13 sets the exposure of the next photographed image. The setting of the exposure may be performed by the method of (A) or (B) above. Then, the process returns to step S103.

  (Step S107) The movement control unit 16 controls the movement mechanism 11 using the position of the movable body 1 acquired in step S104, and moves the movable body 1 to position the movable body 1. Then, the series of processes related to the movement of the mobile body 1 is completed. In step S107, acquisition of a photographed image and movement control using a marker recognized in the acquired photographed image may be repeatedly performed even during movement for positioning. In that case, the captured image of the marker may be acquired using the exposure setting of the captured image acquired last, and the processing of steps S103 to S106 is repeated each time imaging is performed at a new imaging position. It is also good. Here, the movement control using the marker may be movement control according to the position of the mobile body 1 acquired using the marker.

  FIG. 3 is a flow chart showing the operation of the mobile unit 1 which controls imaging according to the method (2). In the flowchart of FIG. 3, steps S101, S102, and S107 are the same as the flowchart of FIG. 2, and the description thereof will be omitted.

  (Step S201) The photographing unit 12 acquires a plurality of photographed images of the marker such that the exposure of each photographed image is different according to the control by the photographing control unit 13. The plurality of acquired photographed images may be stored in a recording medium (not shown).

  (Step S202) The position acquisition unit 14 sets a counter i to one.

  (Step S203) The position acquisition unit 14 acquires the position of the mobile body 1 using the acquired i-th captured image. In the case of an error, it may be impossible to obtain the position.

  (Step S204) The position acquisition unit 14 determines whether acquisition of the position is an error, that is, whether the ith captured image is an error. Then, in the case of an error, the process proceeds to step S205, and otherwise, the process proceeds to step S107.

  (Step S205) The position acquisition unit 14 increments the counter i by one.

  (Step S206) The position acquisition unit 14 determines whether the acquired i-th captured image exists. Then, if the i-th captured image is present, the process returns to step S203. If not, all the captured images obtained become an error, and thus the processing is ended on the assumption that an abnormality has occurred.

  The order of the processes in the flowcharts of FIGS. 2 and 3 is an example, and the order of each step may be changed as long as the same result can be obtained. Further, although not included in the flowcharts of FIGS. 2 and 3, acquisition of the current position by the current position acquisition unit 15 is assumed to be repeatedly performed until the marker is photographed. In addition, it is preferable that the moving body 1 be stopped when the photographing unit 12 is photographing a marker (steps S103 and S201).

  As described above, according to the movable body 1 of the present embodiment, it is possible to appropriately capture a marker used for positioning even in a backlit condition or the like. For example, as shown in FIG. 4A, it is assumed that the shutter 9 is present behind the marker 5. In FIG. 4A, since the shutter 9 is closed, shooting of the marker 5 does not turn backlit, but as shown in FIG. 4B, shooting of the marker 5 turns backlit when the shutter 9 is vacant. Sometimes. Even in such a case, in the mobile object 1 according to the present embodiment, as described above, imaging with the appropriate exposure of the marker can be performed, and appropriate movement control using the marker can be performed. It will be realized. In addition, since it is not necessary to separately provide a light quantity detection unit or the like in order to obtain a photographed image of the proper exposure of the marker, it is possible to realize photographing of such a proper exposure with a simple configuration. In order to capture the marker with the correct exposure, it is conceivable to perform shooting with automatic exposure. In that case, since the exposure becomes appropriate over the entire captured image, the whiteout or black for the marker portion is considered. It may be smashed and not properly exposed. Therefore, it is preferable to control the exposure at the time of shooting as in the present embodiment.

  In the mobile unit 1 according to the present embodiment, detection of an obstacle may be performed. The detection of the obstacle may be performed using, for example, a result of distance measurement by a distance measurement sensor that measures the distance to an object around in a plurality of directions, or may be performed using a contact sensor or the like. Good. And when an obstacle is detected, movement control part 16 may perform movement control so that a collision with the obstacle may be prevented. The movement control may be, for example, stopping or decelerating movement, detouring of an obstacle, or the like.

  Further, in the present embodiment, when the current position is not used for error determination and movement control, the moving body 1 may not include the current position acquisition unit 15.

  Also, in the above embodiment, each processing or each function may be realized by centralized processing by a single device or a single system, or distributed processing by a plurality of devices or a plurality of systems. It may be realized by

  Further, in the above embodiment, the transfer of information performed between the components is performed by, for example, one of the components if the two components performing the transfer of information are physically different. It may be performed by the output of the information and the reception of the information by the other component, or if the two components that exchange the information are physically the same, one of the components It may be performed by moving from the phase of processing corresponding to to the phase of processing corresponding to the other component.

  Further, in the above embodiment, information related to processing executed by each component, for example, information received, acquired, selected, generated, transmitted, or received by each component Also, information such as threshold values, mathematical expressions, addresses and the like used by each component in processing may be held temporarily or for a long time in a recording medium (not shown), even if not specified in the above description. Further, each component or a storage unit (not shown) may store information in the recording medium (not shown). Each component or a reading unit (not shown) may read information from the recording medium (not shown).

  Further, in the above embodiment, when the information used in each component or the like, for example, information such as a threshold or an address used in processing by each component or various setting values may be changed by the user, Although not explicitly stated in the description, the user may or may not be able to change the information as appropriate. When the user can change such information, the change is realized, for example, by a receiving unit (not shown) that receives a change instruction from the user and a change unit (not shown) that changes the information according to the change instruction. May be The acceptance of the change instruction by the acceptance unit (not shown) may be, for example, acceptance from an input device, reception of information transmitted via a communication line, or acceptance of information read from a predetermined recording medium .

  Further, in the above embodiment, when two or more components included in the mobile unit 1 have a communication device, an input device, etc., the two or more components may have a physically single device. Or may have separate devices.

  Further, in the above embodiment, each component may be configured by dedicated hardware, or a component that can be realized by software may be realized by executing a program. For example, each component can be realized by a program execution unit such as a CPU reading and executing a software program recorded on a recording medium such as a hard disk or a semiconductor memory. At the time of the execution, the program execution unit may execute the program while accessing the storage unit or the recording medium. The program may be executed by being downloaded from a server or the like, or may be executed by being read out of a program recorded on a predetermined recording medium (for example, an optical disc, a magnetic disc, a semiconductor memory, etc.) Good. Also, this program may be used as a program that constitutes a program product. Also, the computer that executes the program may be singular or plural. That is, centralized processing may be performed, or distributed processing may be performed.

  Further, it is needless to say that the present invention is not limited to the above embodiments, and various modifications are possible, which are also included in the scope of the present invention.

  As mentioned above, according to the moving body by this invention, the effect that the marker used for positioning can be image | photographed appropriately is acquired, and it is useful as a moving body which performs positioning using a marker.

DESCRIPTION OF SYMBOLS 1 mobile body 11 moving mechanism 12 imaging | photography part 13 imaging | photography control part 14 position acquisition part 15 present position acquisition part 16 movement control part

Claims (9)

It is a mobile that moves autonomously,
An imaging unit that acquires a captured image of a marker;
A position acquisition unit that acquires the position of the moving object using a marker recognized in the captured image;
A moving mechanism for moving the moving body;
A movement control unit that controls the movement mechanism using the position acquired by the position acquisition unit;
And a shooting control unit that controls the shooting unit to obtain shot images with different exposures,
The movable body, wherein the position acquisition unit acquires the position of the movable body using a captured image that does not cause an error. The mobile unit according to claim 1, wherein the shooting control unit causes the shooting unit to obtain a shot image having a different exposure from the shot image when a shot image becomes an error. The mobile unit according to claim 2, wherein the photographing control unit changes the exposure of a newly acquired photographed image as predetermined. The moving object according to claim 2, wherein the photographing control unit changes the exposure of a newly acquired photographed image using the luminance of the acquired photographed image. The mobile unit according to claim 4, wherein the photographing control unit changes the exposure of a newly acquired photographed image by using the entire luminance value of the acquired photographed image. The mobile unit according to claim 4, wherein the photographing control unit changes an exposure of a newly acquired photographed image by using a luminance value of a predetermined part of the acquired photographed image. The photographing control unit controls the photographing unit to acquire a plurality of photographed images with different exposures,
The movable body according to claim 1, wherein the position acquisition unit acquires the position of the movable body using a captured image that does not cause an error among the plurality of captured images acquired. The imaging control unit causes the imaging unit to acquire a captured image when the positional relationship between the marker and the moving body is predetermined.
The mobile unit according to any one of claims 1 to 7, wherein the position acquisition unit generates an error when a marker recognized in the captured image deviates from a predetermined one by more than a threshold. The mobile device further includes a current position acquisition unit that acquires the current position of the moving body without using the marker,
The said position acquisition part makes an error, when the position acquired using the marker recognized in the said picked-up image and the position acquired by the said present position acquisition part differ by more than a threshold value. The mobile according to any one of 7.

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