Moving body

Abstract

To provide a moving body that can move without using SLAM, GPS, and a magnetic tape on a floor surface.SOLUTION: A moving body 1 that moves by using a visually recognizable guide line provided on a floor surface includes: an image acquisition unit 11 that acquires a captured image of an area ahead of the moving body; an image conversion unit 12 that converts the captured image into a captured image viewed from above; a grayscale conversion unit 13 that performs grayscale conversion on the captured image by using a color of the guide line as a reference; a specifying unit 14 that specifies a center of gravity and a direction of the guide line in a specific area image that is an image of a specific area of the captured image after conversion by the image conversion unit 12 and the grayscale conversion unit 13; a moving mechanism 15; and a movement control unit 16 that controls the moving mechanism 15 so that the moving body 1 moves along the guide line by using the specified center of gravity and the direction of the guide line. In this manner, the moving body 1 can move along the guide line having an arbitrary shape such as a straight line or a curved line.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a moving body that moves using a visually recognizable guiding line provided on the floor surface.

Background Art

[0002] Conventionally, in an automated guided vehicle or the like, self-position estimation has been performed using SLAM (Simultaneous Localization and Mapping) (see, for example, Patent Document 1). In a moving environment where the layout does not change much, by using SLAM, it is possible to realize desired movement while appropriately estimating the self-position.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] On the other hand, in a moving environment where the layout is frequently changed, such as in a factory, movement using SLAM becomes difficult. Also, in a building such as a factory, movement control using GPS (Global Positioning System) is difficult. Further, it is also conceivable to detect a magnetic tape provided on the floor surface and move the moving body along the magnetic tape. However, since the magnetic tape is usually embedded in the floor surface, when changing the route of the moving body, there is a drawback that the work load for changing the position of the magnetic tape is excessive.

[0005] The present invention has been made to solve the above problems, and an object thereof is to provide a moving body that can move appropriately without using SLAM, GPS, or a magnetic tape provided on the floor surface.

Means for Solving the Problems

[0006] To achieve the above object, a moving body according to one aspect of the present invention is a moving body that moves using a visually recognizable guiding line provided on the floor surface, and includes an image acquisition unit that acquires a captured image of the front of the moving body, an image conversion unit that converts the captured image into a captured image viewed from above, a grayscale conversion unit that converts the captured image into grayscale so that the difference from the value of the pixel of the reference color, which is the color of the guiding line, becomes larger as the color difference from the reference color becomes larger, a specifying unit that specifies the center of gravity and the direction of the guiding line in a specific region image, which is an image of a specific region of the captured image subjected to the image conversion by the image conversion unit and the grayscale conversion by the grayscale conversion unit, a moving mechanism that moves the moving body, and a movement control unit that controls the moving mechanism so that the moving body moves along the guiding line using the center of gravity and the direction of the guiding line specified by the specifying unit.

Advantages of the Invention

[0007] According to the moving body according to one aspect of the present invention, it can move along a visually recognizable guiding line provided on the floor surface. Therefore, it can move appropriately without using SLAM, GPS, or a magnetic tape provided on the floor surface.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6A

Figure 6B

Figure 7

Embodiments for Carrying out the Invention

[0009] Hereinafter, the moving body according to the present invention will be described using embodiments. In the following embodiments, components and steps with the same reference numerals are the same or corresponding, and repeated descriptions may be omitted. The moving body according to the present embodiment can move along a guiding line of an arbitrary shape such as a straight line or a curve.

[0010] FIG. 1 is a block diagram showing the configuration of the moving body 1 according to the present embodiment. The moving body 1 according to the present embodiment moves using a visually recognizable guiding line provided on the floor surface, and includes an image acquisition unit 11, an image conversion unit 12, a grayscale conversion unit 13, a specifying unit 14, a moving mechanism 15, and a movement control unit 16. The use of the moving body 1 is not particularly limited, but the moving body 1 may be, for example, a moving body that performs conveyance, or a moving body for other uses such as security and cleaning.

[0011] It is assumed that a guiding line is provided on the floor surface of the moving environment of the moving body 1. The floor surface of the moving environment is preferably horizontal normally. The guiding line may be provided, for example, to guide the moving body 1, or may be a partitioning line or the like for partitioning other uses, such as a passage for people or a traveling area for a forklift. The guiding line may be, for example, a tape-like object such as vinyl tape pasted on the floor surface, or may be provided by applying paint to the floor surface. The guiding line is preferably a line with a certain width, for example. The guiding line is visually recognizable. That is, the guiding line can be detected in the image. Since the guiding line is visually recognizable, it is preferably a color different from that of the floor surface. The guiding line may be, for example, a line of a specific color determined in advance. Also, the guiding line may be, for example, a straight line or a curve.

[0012] FIG. 2 is a plan view showing an example of the situation in a factory where a guiding line 5 is provided on the floor surface. In FIG. 2, the guiding line 5 may indicate, for example, the moving path of the moving body 1 in the passage between the arranged objects 7 in the factory.

[0013] The image acquisition unit 11 acquires a captured image of the front of the moving body 1. The image acquisition unit 11 may be, for example, an optical device such as a camera that captures an image, or may be a device that acquires an image captured by an optical device such as a camera. In the present embodiment, the case where the image acquisition unit 11 is a camera will be mainly described. The captured image is preferably a color image. The image acquisition unit 11 preferably repeats the acquisition of the captured image. The image acquisition unit 11 may repeat the acquisition of the captured image periodically or irregularly, for example. Also, the image acquisition unit 11 may acquire a moving image, for example. In this case, one frame constituting the moving image may be considered as the captured image.

[0014] The optical axis of the camera for taking the captured image preferably normally faces forward in the traveling direction of the moving body 1. The optical axis may, for example, extend in the horizontal direction, or may face the floor side such that the depression angle is a positive value. Even in the latter case, it is preferable that an area far in the traveling direction is also included in the captured image. Also, for example, the captured image may be taken such that the left-right direction of the captured image is the horizontal direction of the real space. FIG. 3 is a diagram showing an example of the captured image taken when the moving body 1 exists at the position shown in FIG. 2. As shown in FIG. 3, the captured image becomes an image with perspective.

[0015] The image conversion unit 12 converts the captured image acquired by the image acquisition unit 11 into a captured image viewed from above. Note that the converted captured image may also be referred to as a planar image. The planar image, which is a captured image viewed from above, may be, for example, an image viewed from a direction perpendicular to the floor surface, for example, the vertical direction. The image conversion unit 12 may, for example, convert the captured image into a planar image by a homography transformation. Note that a method for converting a captured image into a planar image is known, and a detailed description thereof is omitted. FIG. 4 is a diagram showing an example of the planar image obtained by converting the captured image shown in FIG. 3. As shown in FIG. 4, the planar image becomes an image without perspective. The image conversion unit 12 may, for example, repeatedly convert each of the acquired captured images into a planar image, which is a captured image viewed from above.

[0016] The grayscale conversion unit 13 converts the captured image into grayscale based on the color of the guiding line. Specifically, the grayscale conversion unit 13 may convert the captured image into grayscale such that the difference from the pixel value of the reference color becomes larger as the color difference from the reference color, which is the color of the guiding line, becomes larger. That is, when converting a pixel of a certain color into grayscale, the closer the color is to the reference color, the closer the value of the pixel after grayscale conversion is to the value of the pixel of the reference color after grayscale conversion, and the farther the color is from the reference color, the farther the value of the pixel after grayscale conversion is from the value of the pixel of the reference color after grayscale conversion, and the grayscale conversion may be performed. For example, when converting to 8-bit grayscale, the pixel value of the reference color may be set to 255, and the conversion to grayscale may be performed such that the value becomes closer to 0 as the color difference from the reference color becomes larger. By doing so, the guiding line can be detected more stably in the converted grayscale planar image. In this case, as an example, the grayscale conversion may be performed such that pixels closer to the reference color have larger luminance values. For example, the guiding line of the reference color may be converted to white by grayscale conversion.

[0017] The color difference from the reference color may be specified, for example, according to the distance from the reference color in the color space. The color space may be, for example, the RGB color space, the CMY color space, the HSV color space, the xyz color space, or the like. For example, when the color difference from the reference color is specified according to the distance from the reference color in the HSV color space, the color difference according to the distance from the reference color may be specified using only the hue (H) axis in the HSV color space.

[0018] As an example, the grayscale conversion unit 13 may perform grayscale conversion on the captured image after conversion by the image conversion unit 12. In the present embodiment, this case will be mainly described. FIG. 5 is a diagram showing an example of a captured image obtained by performing grayscale conversion on the planar image shown in FIG. 4. For example, as shown in FIG. 5, in the captured image after grayscale conversion, the luminance value of the guiding line 5 may be the largest value. The grayscale conversion unit 13 may, for example, convert each of the repeatedly acquired planar images into grayscale images.

[0019] Note that the order of performing image conversion by the image conversion unit 12 and grayscale conversion by the grayscale conversion unit 13 on the captured image is not limited. For example, grayscale conversion may be performed after converting the captured image into a planar image, or conversion into a planar image may be performed after performing grayscale conversion on the captured image. In the present embodiment, as described above, the former case will be mainly described.

[0020] The specific part 14 identifies the centroid and direction of the guiding line in the specific region image, which is an image of a specific region of the captured image on which image conversion by the image conversion unit 12 and grayscale conversion by the grayscale conversion unit 13 have been performed. The specific region image may be an image of a region determined in advance in the planar image after grayscale conversion. For example, as shown in FIG. 6A, the region of the specific region image 9 in the planar image after grayscale conversion may be determined. Also, usually, the specific region image is an image of a partial region in the planar image after grayscale conversion. It is preferable that the specific region image includes a guiding line. Also, even when there are a plurality of guiding lines in the vicinity of the moving body 1, it is preferable that the position and size of the specific region image are set so that only one guiding line is included in the specific region image. Also, in the planar image, the resolution decreases as the region becomes farther from the moving body 1. Therefore, it is preferable that the specific region image is set in a region not far from the moving body 1 in the planar image. When the moving body 1 is moving along the guiding line, ideally, the relative relationship between the moving body 1 and the guiding line remains constant. Therefore, even in the planar image after grayscale conversion, since the position where the guiding line exists is determined, it is preferable that the specific region image is set to include the position where the guiding line exists. In FIG. 6A, the case where the specific region image 9 is square-shaped is shown, but the specific region image 9 may be rectangular other than square-shaped, or may have other shapes. The details of the process for identifying the centroid and direction of the guiding line in the specific region image will be described later.

[0021] The moving mechanism 15 moves the moving body 1. In the present embodiment, the case where the moving mechanism 15 is a mechanism for running the moving body 1 on the floor surface will be mainly described. The moving mechanism 15 may be, for example, one that can move the moving body 1 in all directions, or it may not be so. Moving in all directions means being able to move in an arbitrary direction. The moving mechanism 15 may have, for example, a traveling section (such as wheels) and a driving means (such as a motor or an engine) for driving the traveling section. When the moving mechanism 15 can move the moving body 1 in all directions, the traveling section may be an all-directional moving wheel (such as an omni wheel or a mecanum wheel). Since a known moving mechanism 15 can be used, a detailed description thereof will be omitted.

[0022] The movement control unit 16 controls the moving mechanism 15 so that the moving body 1 moves along the guiding line using the center of gravity of the guiding line and the direction of the guiding line specified by the specifying unit 14. That the moving body 1 moves along the guiding line may mean that the moving body 1 travels in a direction parallel to the guiding line. The moving body 1 may, for example, move along the guiding line on the guiding line, or may move along the guiding line at a position slightly away from the guiding line. In the latter case, the moving body 1 may move along a virtual line parallel to the guiding line on the virtual line. The virtual line is a line that does not exist in the moving area of the moving body 1, that is, a line that cannot be visually observed in the actual environment. In this case, the moving body 1 can move parallel to the guiding line at a position different from the guiding line. For example, even when a partition line or the like provided near an arrangement in a factory or the like is used as the guiding line, by moving the moving body 1 on a virtual line parallel to the direction in which the guiding line moves away from the arrangement, the possibility of the moving body 1 coming into contact with the arrangement can be reduced. The relative positional relationship between the guiding line and the moving body 1 is determined in advance, and the movement control unit 16 may perform movement control of the moving body 1 accordingly. As an example, the distance between the guiding line and the virtual line may be set in advance. Specific movement control using the center of gravity of the specified guiding line and the direction of the guiding line will be described later.

[0023] How the moving body 1 moves along the guiding line may be set in advance. Then, the movement control unit 16 may control the movement according to the guiding line by using, for example, the movement distance obtained by using an encoder or the like provided in the movement mechanism 15 according to the setting. For example, the movement control unit 16 may move the moving body 1 along the guiding line by a predetermined distance, change the traveling direction of the moving body 1 to a predetermined direction at the branch point of the guiding line after the movement, and then repeat the process of moving the moving body 1 along the guiding line by a predetermined distance again. Further, the movement control unit 16 may stop the moving body 1 at a predetermined position. And at that position, for example, loading and unloading of the object to be conveyed may be performed.

[0024] Also, when a marker is arranged in the movement area of the moving body 1, the movement control unit 16 may perform movement control using the marker. The marker may indicate, for example, the stop position of the moving body 1 or the traveling direction of the moving body 1 at the branch point of the guiding line. In this case, for example, the movement control unit 16 may detect the marker by using template matching or the like in the captured image which is a planar image before grayscale conversion, and perform movement control using the detected marker. As an example, the marker may be arranged on the guiding line.

[0025] Next, a process of specifying the center of gravity of the guiding line 5 and the direction of the guiding line 5 in the specific region image 9 will be described. In this process, as shown in FIG. 6B, in the specific region image 9, a local coordinate system which is a two-dimensional xy orthogonal coordinate system is set such that the longitudinal direction of the moving body 1 is the x-axis direction with the center as the origin, and the left-right direction which is the direction orthogonal to the longitudinal direction is the y-axis direction. Note that the positive direction of the x-axis corresponds to the front in the traveling direction of the moving body 1. Also, let the indices for identifying the pixels in the x-axis direction and the y-axis direction be i and j, respectively. It is assumed that i and j are integer values that become 0 at the pixel of the origin of the local coordinate system and are incremented by 1 for each pixel along the positive directions of the x-axis and the y-axis. In this case, the specifying unit 14 may obtain the center of gravity (x g , y g ) of the guiding line 5 as follows. Note that p ij is the pixel value at the position corresponding to the indices i and j. Also, x min and x max are the minimum index value and the maximum index value in the x-axis direction in the specific region image 9, respectively. Also, y min and y max are the minimum index value and the maximum index value in the y-axis direction in the specific region image 9, respectively.

Equation

[0026] Also, the specifying unit 14 may specify, for example, the direction of the guiding line 5 which is the direction of the first principal component of the guiding line 5 in the specific region image 9. In this case, the direction of the guiding line 5 is specified by performing principal component analysis. In principal component analysis, since the direction with the largest variance is the direction of the first principal component, the specifying unit 14 can specify the direction of the guiding line 5 by obtaining the direction of the first principal component which is the direction with the largest variance for the pixels of the guiding line 5.

[0027] Specifically, for each pixel included in the specific region image 9, the specifying unit 14 determines the center of gravity (x g , yg ) Prepare the following set of data centered around it. The set of data is a pair consisting of the result of multiplying the pixel value by a value corresponding to the distance to the centroid in the x-axis direction and the result of multiplying the pixel value by a value corresponding to the distance to the centroid in the y-axis direction. If the total number of pixels included in the specific region image 9 is n, there will be n such sets of data. Here, let the number of pixels in the x-axis direction in the specific region image 9 be n x and the number of pixels in the y-axis direction be n y then n = n x ×n y . (p ij (i - x g ), p ij (j - y g ))

[0028] Next, let X be an n×2 matrix formed by arranging n sets of the above data. Then, the specific part 14 calculates the covariance C = X T X / n. Also, the specific part 14 calculates the eigenvectors and eigenvalues of this covariance matrix C. Then, it obtains the eigenvector (x c , y c ) corresponding to the largest eigenvalue. The direction of this eigenvector (x c , y c ) is the direction of the first principal component, and the direction of the guiding line 5 will be indicated by this direction. If the angle between the direction of the guiding line 5 and the x-axis is θ, then θ is as follows. θ = tan -1 (y c / x c )

[0029] Since the direction of the eigenvector (x c , y c ) is the direction of the guiding line 5, specifying the direction of the guiding line 5 by the specific part 14 means, for example, it may be to specify the eigenvector (x c , y c ), or it may be to specify the angle θ between the direction of the guiding line 5 calculated by that eigenvector and the x-axis.

[0030] Here, the case of specifying the direction of the guiding line 5 using principal component analysis has been mainly described, but it doesn't have to be so. The specifying unit 14 may specify the direction of the guiding line 5 using other methods. For example, the specifying unit 14 may specify the direction of the guiding line 5 by template matching. In this case, as an example, the specifying unit 14 may perform template matching using a linear template, and use the linear direction of the template that matches the guiding line 5 included in the specific region image 9 as the direction of the guiding line 5.

[0031] Also, in the above description, the case of specifying the centroid and direction of the guiding line 5 using all the pixel values of the specific region image 9, which is the result of performing grayscale conversion so that the pixel value of the reference color becomes the largest pixel value (i.e., the pixel value corresponding to white), has been described, but it doesn't have to be so. For example, the specifying unit 14 may extract the pixels of the guiding line 5 in the specific region image 9, and use the extracted pixels of the guiding line 5 to specify the centroid and direction of the guiding line 5. In this case, for example, when grayscale conversion is performed so that the pixel value of the reference color becomes the largest pixel value, the specifying unit 14 may extract the pixels with pixel values exceeding a predetermined threshold in the specific region image 9, and use the extracted pixels to specify the centroid and direction of the guiding line 5.

[0032] Next, the movement control using the specifying result by the specifying unit 14 will be described. The movement control unit 16 may, for example, determine the movement speed of the moving body 1 in the left - right direction such that the centroid of the guiding line 5 specified by the specifying unit 14 becomes the center in the left - right direction orthogonal to the front - rear direction of the moving body 1 in the specific region image 9. In the specific region image 9 shown in FIG. 6B, as described above, the direction of the x - axis, that is, the up - down direction, is the front - rear direction of the moving body 1. Therefore, the movement control unit 16 g determines the movement speed v of the moving body 1 in the left - right direction such that the specified centroid y y becomes the center in the left - right direction of the specific region image 9, that is, the position of the origin in the y - axis direction. yIt may be determined as follows. That is, in the specific region image 9, the greater the distance between the center of gravity of the guiding line 5 in the left - right direction of the moving body 1 and the center of the image, the greater the magnitude of the moving speed v in the left - right direction y of the moving speed v y may be determined. v y =αy g

[0033] Also, the movement control unit 16 may determine the rotation speed of the moving body 1 so that the moving body 1 travels in the direction of the guiding line 5 specified by the specifying unit 14. That is, the rotation speed of the moving body 1 may be determined so that the direction of the specified guiding line 5 is the front - rear direction of the moving body 1 in the specific region image 9. The movement control unit 16 may determine, for example, the rotation speed ω of the moving body 1 so that the direction of the specified guiding line 5 is the front - rear direction of the moving body 1, that is, the x - axis direction. In this case, for example, the rotation speed ω may be determined as follows. That is, in the specific region image 9, the greater the angle formed by the direction of the guiding line 5 and the front - rear direction of the moving body 1, the greater the magnitude of the rotation speed ω, so that the rotation speed ω may be determined. ω=βtan -1 (y c / x c )

[0034] Note that the moving speed v in the front - rear direction of the moving body 1 x , and the above coefficients α, β may be predetermined values. The coefficients α, β may be, for example, positive real numbers respectively. And the movement control unit 16 may control the movement mechanism 15 according to, for example, the determined moving speed v in the left - right direction y and the rotation speed ω, and the predetermined moving speed v in the front - rear direction x . That is, the moving body 1 turns according to the rotation speed ω so that the direction of the specified guiding line is the front - rear direction, and the moving speeds v x , v yMovement control may be performed so as to move in the direction indicated by. By performing such movement, the center of gravity of the guiding line 5 will approach the center in the left - right direction of the moving body 1 in the specific region image 9, and the direction of the guiding line 5 will approach the front - rear direction of the moving body in the specific region image 9.

[0035] By performing such movement control, the moving body 1 can move along the direction of the guiding line 5 and can move so that the relative positional relationship between the moving body 1 and the guiding line 5 becomes constant. That is, the moving body 1 can move along a guiding line 5 having an arbitrary shape such as a straight line or a curve.

[0036] Also, the movement control unit 16 makes the absolute value of the moving speed v of the moving body 1 in the left - right direction smaller as the absolute value of the rotational speed ω of the moving body 1 becomes larger. y of the moving speed v y This is to avoid an extremely large change in the traveling direction of the moving body 1. For this reason, the movement control unit 16 may limit the upper limit of the absolute value of the moving speed v, for example, so as to satisfy the following formula. Note that the constant D is a positive real number determined in advance. y The absolute value of |v y |×|ω|≦D

[0037] Next, the operation of the moving body 1 will be described using the flowchart of FIG. 7. (Step S101) The image acquisition unit 11 determines whether to acquire a photographed image. If a photographed image is to be acquired, the process proceeds to step S102. Otherwise, the process of step S101 is repeated until it is determined to acquire a photographed image. The image acquisition unit 11 may, for example, periodically determine whether to acquire a photographed image.

[0038] (Step S102) The image acquisition unit 11 acquires a captured image. The image acquisition unit 11 may acquire the captured image, for example, by taking a picture or by receiving the captured image. The captured image may be stored in a recording medium (not shown) or the like.

[0039] (Step S103) The image conversion unit 12 converts the captured image into a planar image, which is the captured image viewed from above. Note that the image conversion unit 12 may convert all the acquired captured images into planar images, or may convert some of the captured images into planar images. This is because when the captured images are acquired frequently, it is not always necessary to convert all the captured images into planar images. The planar image may be stored in a recording medium (not shown) or the like.

[0040] (Step S104) The grayscale conversion unit 15 performs grayscale conversion on the planar image such that the difference from the pixel value of the reference color becomes larger as the color difference from the reference color, which is the color of the guiding line, becomes larger. The grayscale-converted planar image may be stored in a recording medium (not shown) or the like.

[0041] (Step S105) The specifying unit 14 specifies the center of gravity and direction of the guiding line using the specific region image in the grayscale-converted planar image. Information indicating the specified center of gravity and direction may be stored in a recording medium (not shown) or the like.

[0042] (Step S106) The movement control unit 16 controls the movement mechanism 15 so that the moving body 1 moves along the guiding line using the specified center of gravity and direction of the guiding line. Then, it returns to Step S101. By repeating the movement control in this Step S106, the moving body 1 can perform a desired movement.

[0043] Note that the order of the processes in the flowchart of FIG. 7 is merely an example, and if the same result can be obtained, the order of each step may be changed. For example, after the grayscale conversion, the image conversion to a planar image may be performed. Also, in the flowchart of FIG. 7, the process ends due to a power-off or an interruption of the process end. For example, when the moving body 1 arrives at the destination, the process of the flowchart of FIG. 7 may end.

[0044] Next, the operation of the moving body 1 according to the present embodiment will be described using a specific example. In this specific example, it is assumed that the moving body 1 moves along the guiding line 5 in the factory shown in FIG. 2. Also, the movement control unit 16 performs movement control according to a route along the guiding line from the starting point to the destination, which is stored in a recording medium (not shown in the figure) in advance.

[0045] First, it is assumed that the moving body 1 exists at the starting position of the movement. The moving body 1 may move to its starting position, for example, by a manual operation of the user. At the starting position of the movement, it is assumed that the moving body 1 and the guiding line have a predetermined positional relationship. After that, when receiving an instruction to start the movement, the moving body 1 starts the process of movement control along the guiding line. Specifically, the image acquisition unit 11 acquires a captured image and passes the acquired captured image to the image conversion unit 12 (steps S101, S102). It is assumed that the captured image is, for example, the one shown in FIG. 3. When receiving the captured image, the image conversion unit 12 converts the captured image into a planar image viewed from above and passes it to the grayscale conversion unit 13 (step S103). The planar image is, for example, the one shown in FIG. 4.

[0046] After that, the grayscale conversion unit 13 performs grayscale conversion on the planar image received from the image conversion unit 12, and passes the captured image after the grayscale conversion to the specifying unit 14 (step S104). In this grayscale conversion, the grayscale conversion is performed so that the difference from the pixel value of the reference color becomes larger as the color difference from the reference color, which is the color of the guiding line, becomes larger. Therefore, it becomes easier to detect the guiding line. The captured image after the grayscale conversion is, for example, the one shown in FIG. 5.

[0047] Upon receiving the planar image after the grayscale conversion, the specifying unit 14 acquires a specific region image, which is an image of a predetermined region in the planar image, specifies the center of gravity and the direction of the guiding line included in the specific region image, and passes the specific result to the movement control unit 16 (step S105). Upon receiving the specific result from the specifying unit 14, the movement control unit 16 controls the movement mechanism 15 so that the center of gravity of the specified guiding line becomes the position of the center in the left-right direction in the specific region image, and so that the front-rear direction of the moving body 1 becomes the direction of the specified guiding line (step S106). In this way, the moving body 1 moves along the guiding line. By repeating processes such as acquisition of such a captured image, conversion of the captured image, specification of the center of gravity and direction of the guiding line in the converted image, and movement control according to the specific result, the moving body 1 can move to the destination along the guiding line.

[0048] As described above, the mobile body 1 according to the present embodiment can move along a visually recognizable guiding line provided on the floor surface. Therefore, the mobile body 1 can move appropriately without using SLAM, GPS, or a magnetic tape provided on the floor surface. Further, in order to specify the center of gravity and the direction of the guiding line and perform movement control according to the specified result, the mobile body 1 can move not only along a straight guiding line but also along a guiding line having an arbitrary shape such as a curved guiding line with a non-constant curvature or a meandering guiding line. Further, by performing grayscale conversion so that the difference from the value of the pixel of the reference color, which is the color of the guiding line, becomes larger as the color difference from the reference color becomes larger, the guiding line can be stably specified in the captured image after grayscale conversion. Further, by specifying the center of gravity and the direction of the guiding line in a specific region image, which is a partial image of the planar image after grayscale conversion, even when a plurality of guiding lines are included in the vicinity of the mobile body 1, movement control can be performed so that the mobile body 1 moves along only a specific guiding line. Further, by specifying the direction of the guiding line using principal component analysis, the direction of the guiding line can be specified more accurately. Further, by appropriately setting the position of the specific region image, for example, the mobile body 1 can be moved so that the relative positional relationship between the mobile body 1 and the guiding line becomes a desired positional relationship. Further, movement along such a guiding line can be realized by an inexpensive sensor such as a camera.

[0049] In addition, in the photographed image after conversion by the image conversion unit 12 and the grayscale conversion unit 13, when the width of the guiding line is large, the identification unit 14 may identify the center of gravity and the direction of the guiding line after highlighting the shape of the guiding line by performing, for example, thinning processing. This is because a thinner line is more suitable for identifying the center of gravity and the direction. The thinning processing may be, for example, image processing in which a line having a width is thinned by narrowing the line width, or edge detection. As the former thinning processing, for example, Tamura, Hilditch, Zhang-Suen, and other algorithms are known in which an image is binarized and then thinned. The thinning processing may also be performed by, for example, filter processing. In the latter edge detection, normally, edges on both sides of the width direction of the guiding line are detected, but edge detection may be performed so as to leave only one edge, for example. In order to retain only one edge, for example, when detecting an edge using a differential value such as a brightness value, only pixels whose differential value is greater than a positive threshold value may be detected as edges, and pixels whose differential value is less than a negative threshold value may not be detected as edges.

[0050] Furthermore, when the moving body 1 is capable of moving in multiple directions, such as an omnidirectional dolly, the image acquisition unit 11 may be able to acquire captured images of the area ahead in each of the multiple moving directions. In this case, for example, the moving body 1 may be provided with a camera for capturing captured images in each of the multiple directions. The image acquisition unit 11 may then acquire captured images of the area ahead in the moving direction according to the current moving direction.

[0051] In addition, in the above embodiments, each process or function may be realized by centralized processing in a single device or a single system, or may be realized by distributed processing in multiple devices or multiple systems.

[0052] In the above-described embodiment, each component may be configured by dedicated hardware, or for components that can be realized by software, they may be realized by executing a program. For example, each component can be realized by a program execution unit such as a CPU reading out and executing a software program recorded on a recording medium such as a hard disk or a semiconductor memory. At the time of its execution, the program execution unit may execute the program while accessing a storage unit or a recording medium. Further, the program may be executed by being downloaded from a server or the like, or may be executed by reading out a program recorded on a predetermined recording medium (for example, an optical disk, a magnetic disk, a semiconductor memory, etc.). Further, this program may be used as a program constituting 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.

[0053] Further, the above embodiments are examples for specifically implementing the present invention and do not limit the technical scope of the present invention. The technical scope of the present invention is indicated by the claims rather than the description of the embodiments, and it is intended that changes within the literal scope of the claims and the scope of equivalent meaning are included.

Description of Reference Numerals

[0054] 1 Mobile body, 11 Image acquisition unit, 12 Image conversion unit, 13 Grayscale conversion unit, 14 Specifying unit, 15 Movement mechanism, 16 Movement control unit

Claims

1. A moving body that moves using a visually recognizable guiding line provided on a floor surface, an image acquisition unit that acquires a captured image of the front of the moving body, an image conversion unit that converts the captured image into a captured image viewed from above, a grayscale conversion unit that converts the captured image into grayscale such that the difference from the value of the pixel of the reference color, which is the color of the guiding line, becomes larger as the color difference from the reference color becomes larger, a specifying unit that specifies the center of gravity and the direction of the guiding line in a specific region image, which is an image of a specific region of the captured image subjected to the image conversion by the image conversion unit and the grayscale conversion by the grayscale conversion unit, a moving mechanism that moves the moving body, and a movement control unit that controls the moving mechanism so that the moving body moves along the guiding line using the center of gravity and the direction of the guiding line specified by the specifying unit. A moving body comprising the above.

2. The moving body according to claim 1, wherein the specifying unit specifies the direction of the guiding line, which is the direction of the first principal component of the guiding line in the specific region image.

3. The movement control unit determines the moving speed of the moving body in the left - right direction so that the center of gravity of the guiding line specified by the specifying unit becomes the center in the left - right direction orthogonal to the front - rear direction of the moving body in the specific region image, determines the rotational speed of the moving body so that the moving body travels in the direction of the guiding line specified by the specifying unit, and controls the moving mechanism according to the determined moving speed and rotational speed. The moving body according to claim 1 or claim 2.

4. The moving body according to claim 3, wherein the movement control unit determines the moving speed such that the absolute value of the moving speed in the left - right direction of the moving body becomes smaller as the absolute value of the rotational speed of the moving body becomes larger.

Images