Marker

Abstract

To provide a marker capable of precisely recognizing a position of a marker.SOLUTION: A position recognition part 3 of a marker 1 changes intensity of light of visual information that can be observed in an observation position according to an observation angle θ to the position recognition part 3 from an observation position. Such a change in intensity of light can be used as a parameter for showing a minute change in the observation angle θ by previously grasping a correspondence to the observation angle θ. A method for calculating the observation angle θ by grasping a change in intensity of light can reduce processes of occurrence of precision deviation as compared with a method (for example, a method in Figure 8 below) for calculating an observation angle by grasping a positional relationship of patterns in visual information.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a marker.

Background Art

[0002] Conventionally, markers such as those described in Patent Document 1 are known. This marker is attached to an object in order to recognize the position, orientation, etc. of the object. By photographing the marker with a camera, the relative positional relationship between the camera and the marker can be recognized based on how the marker appears in the image.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Here, the marker as described above is configured to obtain predetermined visual information from an observation position in order to indicate the relative positional relationship between the camera and the marker. Then, based on the positional relationship such as the pattern of visual information in the image, the positional relationship between the camera and the marker is calculated, but there is a possibility of accuracy deviation when grasping the positional relationship. In this case, the accuracy of recognizing the position of the marker may decrease.

[0005] An object of the present invention is to provide a marker capable of recognizing the position of a marker with high accuracy.

Means for Solving the Problems

[0006] A marker according to an aspect of the present invention is a marker having a position recognition unit in which visual information observed at an observation position changes according to the direction of observation, and the position recognition unit changes the light intensity of the visual information observable at the observation position according to the observation angle with respect to the position recognition unit from the observation position.

[0007] The marker position recognition unit changes the intensity of the light of the visual information observable at the observation position according to the observation angle of the position recognition unit from the observation position. By grasping in advance the correspondence relationship with the observation angle, such a change in the light intensity can be used as a parameter indicating a change in a minute observation angle. In addition, the method of calculating the observation angle by grasping the change in the light intensity can reduce the processes in which accuracy deviation occurs as compared with the method of calculating the observation angle by grasping the positional relationship of the patterns in the visual information. From the above, it becomes possible to recognize the position of the marker with high accuracy.

[0008] The position recognition unit may include a plurality of lens units arranged and a recognition unit formed on the back side of the lens unit for forming visual information. In this case, it can be set as a suitable configuration as the position recognition unit.

[0009] A plurality of recognition units may be formed separately from each other for each lens unit. Such a position recognition unit can increase the amount of information obtained from the visual information as compared with a position recognition unit in which one recognition unit is formed for each lens unit.

[0010] The recognition unit may have a shape that changes the intensity of the light observable at the observation position according to the observation angle. In this case, it becomes possible to easily change the light intensity only by adjusting the shape of the recognition unit.

[0011] The position recognition unit may include a retroreflective member provided on the back side of the lens unit and the recognition unit. In this case, in the visual information, the portion corresponding to the recognition unit can be strongly illuminated by retroreflection. Therefore, it becomes possible to grasp the change in the light intensity in a state where the influence of disturbance factors such as sunlight and a dark place is reduced.

[0012] The position recognition unit can display a plurality of visual regions separated from each other as visual information, and may change the number of visual regions according to the observation angle with respect to the position recognition unit from the observation position, and may also change the light intensity of any one of the visual regions. Grasping the number of visual regions can be more easily performed than grasping the change in the light intensity of the visual regions. Therefore, it becomes possible to grasp the approximate observation angle based on the number of visual regions and to grasp the minute observation angle based on the change in the light intensity of the visual regions.

[0013] A marker according to one aspect of the present invention is a marker having a position recognition unit in which the visual information observed at the observation position changes according to the observation direction. The position recognition unit can display a visual region shown in a predetermined display mode as visual information, and may change at least one of the shape and the number of visual regions observable at the observation position according to the observation angle with respect to the position recognition unit from the observation position.

[0014] The position recognition unit of the marker changes at least one of the shape and the number of visual regions observable at the observation position according to the observation angle with respect to the position recognition unit from the observation position. Such changes in the shape and number of visual regions can be used as an index indicating the change in the observation angle by grasping the correspondence with the observation angle in advance. In addition, the method of calculating the observation angle by grasping the changes in the shape and number of visual regions can reduce the steps in which accuracy deviation occurs compared to the method of calculating the observation angle by grasping the positional relationship of the patterns in the visual information. From the above, it becomes possible to recognize the position of the marker with high accuracy.

Advantages of the Invention

[0015] According to the present invention, it is possible to provide a marker capable of recognizing the position of the marker with high accuracy.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Mode for Carrying Out the Invention

[0017] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or equivalent elements are denoted by the same reference numerals, and redundant descriptions are omitted.

[0018] FIG. 1 is a diagram showing a usage mode of the marker 1 according to the present embodiment. FIG. 1 shows a state when the forklift 100 approaches the handling object 101 in order to handle the handling object 101. The marker 1 is attached to the handling object 101. The forklift 100 includes a camera 102 and an arithmetic unit 103. The camera 102 photographs the handling object 101. Note that the camera 102 has a light that can irradiate light to the observation range. The arithmetic unit 103 calculates the positional relationship between the forklift 100 and the marker 1 based on the image of the marker 1 among the images photographed by the camera 102. Thereby, the arithmetic unit 103 calculates the positional relationship between the forklift 100 and the handling object 101.

[0019] Note that the marker 1 may be used for purposes other than aligning the forklift 100. For example, in FIG. 1, instead of the forklift 100, a collaborative robot arm may be employed. In this case, FIG. 1 shows the state when the collaborative robot arm approaches the reference marker in order to align based on the alignment reference marker (corresponding to "101"). The marker 1 is attached to the reference marker. The collaborative robot arm is provided with a camera 102 and an arithmetic unit 103 having the same purpose as the forklift 100. In this case, the arithmetic unit 103 calculates the positional relationship between the collaborative robot arm and the marker 1 based on the image of the marker 1 among the images captured by the camera 102. Thereby, the arithmetic unit 103 calculates the positional relationship between the collaborative robot arm and the reference marker. Thereby, although the operation reference coordinate point changes depending on the stop position of the robot arm installed on the Automatic Guided Vehicle (AGV) type automatic transport vehicle, by offsetting the positional information displacement between the reference marker and the robot arm, the positional relationship can be known and a complicated control system operation can be realized.

[0020] FIG. 2(a) is a perspective view showing the marker 1 according to the present embodiment. FIG. 2(b) is a developed perspective view showing the marker 1 according to the present embodiment. As shown in FIG. 2, the marker 1 is a plate-like member having a substantially rectangular shape. The marker 1 includes a mark portion 2 and a position recognition portion 3 on the surface. Note that the arrangement, shape, etc. of the mark portion 2 and the position recognition portion 3 are merely examples and can be changed as appropriate. Further, the marker 1 is configured by laminating a main body portion 10 and a retroreflective member 11. In the following description, the terms "left-right direction D1", "up-down direction D2", and "thickness direction D3" will be used for explanation based on the state when the marker 1 is attached to the cargo handling object 101. However, there is no particular limitation on how the marker 1 is attached to the cargo handling object 101.

[0021] The main body part 10 is a plate-shaped molded part formed by injection molding or the like. The resin material of the main body part 10 may be a thermoplastic resin or a thermosetting resin. The main body part 10 has a position recognition part 3 and a rectangular plate-shaped base part 12. The position recognition part 3 and the base part 12 are integrally formed by a single molding process. Therefore, the position recognition part 3 and the base part 12 are configured as one molded part. The base part 12 has an upper region 12A where the position recognition part 3 is arranged and a lower region 12B where the mark part 2 is arranged. The retroreflective member 11 is a plate-shaped part laminated on the back surface of the base part 12 of the main body part 10, and the surface is configured as a retroreflective surface. The retroreflective member 11 is a reflective member that uses the principle of reflecting light toward the position where the light has entered when light is incident on the retroreflective surface.

[0022] The mark part 2 is formed in the lower region 12B of the base part 12 of the main body part 10. The mark part 2 is a part that displays a predetermined pattern or the like. These patterns function as identification information by being associated with the ID number of the handling object 101 or the like. For example, when the camera 102 detects a predetermined pattern of the mark part 2, the arithmetic unit 103 can identify the handling object 101 by searching for the ID number associated with the pattern (see FIG. 1). The mark part 2 is formed, for example, by attaching a sheet with a pattern printed on the main body part 10. The pattern of the mark part 2 may be indicated in a predetermined color or may be indicated by a retroreflective member.

[0023] The position recognition unit 3 is a part where the visual information observed changes according to the observation direction. That is, according to the positional relationship between the marker 1 and the camera 102, the visual information that can be obtained from the position recognition unit 3 in the image captured by the camera 102 changes. Details of the recognition information obtained by the position recognition unit 3 will be described later. The position recognition unit 3 is formed in the upper region 12A of the base portion 12 of the main body portion 10. Here, the marker 1 according to the present embodiment has position recognition units 3A and 3B. The position recognition unit 3A is arranged in the lower region of the upper region 12A, and the position recognition unit 3B is arranged in the upper region of the upper region 12A. The lower position recognition unit 3A can show visual information for obtaining the relative angle in the left - right direction D1 between the marker 1 and the camera 102. Also, the other position recognition unit 3B can show visual information for obtaining the relative angle in the up - down direction D2 between the marker 1 and the camera 102. Thereby, when the camera 102 detects the images of the respective position recognition units 3A and 3B, the arithmetic unit 103 calculates the relative angles in the left - right direction D1 and the up - down direction D2 between the camera 102 and the marker 1 based on the visual information that can be obtained from each position recognition unit 3, and recognizes the positional relationship between the marker 1 and the forklift 100. Note that around the position recognition units 3A and 3B in the upper region 12A of the base portion 12, a pitch - black line 15 for recognizing the distance between the observation position and the marker 1 is transferred.

[0024] FIG. 3(a) is a plan view of the position recognition unit 3A for obtaining the relative angle in the left - right direction D1 between the marker 1 and the camera 102. FIG. 3(b) shows the cross - sectional structure of the position recognition unit 3A for obtaining the relative angle in the left - right direction D1 between the marker 1 and the camera 102. Note that the position recognition unit 3B for obtaining the relative angle in the up - down direction D2 between the marker 1 and the camera 102 has the same configuration as the position recognition unit 3A except that the direction is different.

[0025] As shown in FIG. 3(b), the position recognition unit 3A includes a lens layer 20 and a pattern transfer layer 21. The lens layer 20 and the pattern transfer layer 21 are integrally formed as molded parts of the main body 10. A retroreflective member 11 is provided on the back surface of the pattern transfer layer 21. The lens layer 20 is a layer in which a plurality of lens portions 22 are arranged. The pattern transfer layer 21 is a layer on which the pattern of the recognition unit 30 for forming visual information is transferred. With such a configuration, the position recognition unit 3A has a plurality of arranged lens portions 22 and a recognition unit 30 that is formed on the back surface side of the lens portion 22 and forms visual information. In the following description, the angle in the left-right direction D1 formed by the optical axis of the camera 102 and the thickness direction D3 of the marker 1 is defined as the observation angle θ with respect to the position recognition unit 3A from the observation position. Also, a state where the optical axis of the camera 102 is perpendicular to the surface of the marker 1 is defined as "observation angle θ = 0°".

[0026] Here, the patterns in the regions other than the recognition unit 30 (general unit 31) are arranged at intervals equal to or greater than the wavelength of the target light source, and an uneven structure having a depth with an aspect ratio of 1 or more is formed. Specifically, in the case of the visible region with a wavelength of 400 nm to 700 nm, an uneven structure body with an interval of 700 nm or more is formed, and the depth is a structure body with an aspect ratio of 1 or more and a depth of 700 nm or more. Further, in the best mode, the interval between the structure bodies is preferably from 10 μm to about 100 μm, and a structure body with an aspect ratio of 1 or more and a depth of from 10 μm to about 100 μm is desirable. Thus, when a structure body that is 10 times or more the wavelength is used, the scattering effect of light can be effectively utilized, so that the pattern contrast of the recognition unit 30 can be improved.

[0027] Also, the uneven structure formed on the pattern transfer layer 21 can function with a periodic uneven structure or a random uneven structure, and can function with a rectangular structure body. Further, by forming an uneven structure having a bullet shape with a tapered tip when viewed from the surface of the pattern transfer layer 21, it is possible to reduce surface reflection, obtain a better light scattering effect, and obtain a pattern of the recognition unit 30 with higher contrast.

[0028] Each lens unit 22 has a curved surface on the front side when viewed from the vertical direction D2, and is configured to extend in the vertical direction D2 with the same cross-sectional shape. By arranging such a plurality of lens units 22 in the left-right direction D1, the lens layer 20 is formed. In the position recognition unit 3B, a plurality of lens units 22 extending in the left-right direction D1 are arranged in the vertical direction D2. The lens unit 22 is composed of a lens called a so-called lenticular lens. When the position recognition unit 3A is viewed with the line of sight AX directed from a certain observation position, due to the influence of the curved surface of the lens unit 22, it is focused at the light collection position CP of the pattern transfer layer 21. Therefore, at the observation position, the image of the light collection position CP of the pattern transfer layer 21 is visually recognized over the entire left-right direction D1 of each lens unit 22. The light collection position CP moves in the left-right direction D1 as the observation angle θ varies.

[0029] Note that the shape of the lens unit 22 is not particularly limited. For example, the curvature of the curved surface of the lens may be changed as appropriate. The number of lens units 22 (as long as there is one or more) and the span are also not particularly limited. Also, the lens unit 22 may be formed by resin molding or may be formed by machining. The lens unit 22 may be configured separately from the main body 10.

[0030] Note that the shape of the lens unit 22 is not particularly limited, but the focal position of the lens unit 22 is located on the surface of the pattern transfer layer 21 in order to resolve the pattern of the recognition unit 30 with high resolution.

[0031] As shown in FIG. 3(a), a plurality of recognition units 30 for forming visual information are formed in the pattern transfer layer 21. In FIG. 3 and other figures, the portions with grayscale correspond to the recognition units 30. Note that in FIG. 3(a), the state of the pattern transfer layer 21 is shown in a different state from the way it actually looks when viewed from the observation position as visual information. In FIG. 3(a), the state of the pattern transfer layer 21 is shown in the way it would look if the light passed through without being focused by the lens unit 22 (assuming that the curved surfaces of the lenses of all the lens units 22 are made flat).

[0032] In this embodiment, among the pattern transfer layer 21, the portion of the recognition unit 30 is in a state where reflection by the retroreflective member 11 is possible, and the portion other than the recognition unit 30 (hereinafter referred to as the general unit 31) is in a state where reflection by the retroreflective member 11 is prevented. For example, when molding the main body 10, the recognition unit 30 is molded as a smooth plane, and the general unit 31 is molded as a rough surface. If the molding surface of the mold corresponding to the recognition unit 30 is made smooth and the molding surface of the mold corresponding to the general unit 31 is made rough, then as visual information, the portion corresponding to the recognition unit 30 appears to shine due to the reflection of the retroreflective member 11. As visual information, the portion corresponding to the general unit 31 appears dark because reflection by the retroreflective member 11 does not occur.

[0033] The shapes and arrangements of the plurality of recognition units 30 will be described. In the pattern transfer layer 21, in the vertical direction D2, recognition regions ER1, ER2, ER3, ER4... in which the recognition units 30 are arranged linearly and blank regions where the recognition units 30 are not provided are alternately formed. In FIG. 3(a), the recognition region ER1 is formed at the lowermost side, and the recognition regions ER2, ER3, ER4... are formed in order from the bottom. In the recognition region ER1, one recognition unit 30 extending linearly in the left-right direction D1 with a certain thickness is formed.

[0034] In recognition regions ER2, ER3, ER4..., a plurality of recognition units 30 have a bilaterally symmetric shape and are arranged bilaterally symmetrically with respect to the center position CL1 of the position recognition unit 3A. Specifically, in the region on the right side of the center position CL1, the recognition units 30 of the recognition regions ER2, ER3, ER4... extend from the center position CL2 of each lens unit 22 toward the left. The length in the left-right direction D1 of each recognition unit 30 gradually decreases in the order of the recognition regions ER2, ER3, ER4.... The left end of the recognition unit 30 of the recognition region ER2 having the longest length extends to a position reaching the center position CL2 of another adjacent lens unit 22 on the left side. The left end of the recognition unit 30 of the recognition region ER3 extends to a position slightly separated to the right from the center position CL2 of another adjacent lens unit 22 on the left side. As a result, a gap is formed between the left end of one recognition unit 30 and the right end (center position CL2 of the lens unit 22) of another adjacent recognition unit 30 on the left side. The size of such a gap gradually increases in the order of the recognition regions ER2, ER3, ER4.... In the region on the left side of the center position CL1, the recognition units 30 of the recognition regions ER2, ER3, ER4... have a configuration bilaterally symmetric to the recognition units 30 of the recognition regions ER2, ER3, ER4... in the right region.

[0035] Here, the number of recognition units for each lens unit will be described. For example, in the position recognition unit 150 of the marker according to the comparative example shown in FIG. 7, one recognition unit 130 extending linearly in the up-down direction D2 is formed for one lens unit 122 (see FIG. 7(a)). In this case, for the lens unit 122 where the condensing position coincides with the recognition unit 130 depending on the observation angle, an image of the recognition unit 130 is displayed on the entire lens unit 122 in the visual information (see FIG. 7(b)). Such a comparative example has a configuration in which one recognition unit 130 is formed for each lens unit 122. On the other hand, in the marker 1 according to the present embodiment, for each lens unit 22, recognition units 30 are formed at the positions of the recognition regions ER1, ER2, ER3, ER4... at intervals in the up-down direction D2. Therefore, a plurality of recognition units 30 separated from each other are formed for each lens unit 22.

[0036] Next, with reference to FIG. 4(a), the shape of each recognition unit 30 will be described. In FIG. 4, the recognition unit 30 on the right side of the center position CL1 (see FIG. 3) is shown, but the recognition unit 30 on the left side has the same shape except for being symmetric about the left and right. As shown in FIG. 4(a), the recognition unit 30 has a main body part 32 and an adjustment part 33. The main body part 32 is a part that extends in the left - right direction D1 with a certain width. The adjustment part 33 is provided at the end of the left side (center position CL1 side) of the main body part 32 and is a part whose width becomes narrower as it extends to the left. In the present embodiment, the adjustment part 33 is formed in a triangular shape so as to taper toward the left. When the condensing position CP is the general part 31 on the left side of the recognition unit 30 (condensing position CP1), as shown in the area on the right side of the recognition areas ER3 and ER4 in FIG. 6(a), visual information is shown such that the line cannot be seen. When the condensing position CP is the main body part 32 of the recognition unit 30 (condensing position CP3), as shown in the area on the right side of the recognition areas ER1, ER2, and ER3 in FIG. 6(d), visual information is shown such that a line with a width corresponding to the main body part 32 (referred to as the reference width) can be seen. When the condensing position CP is the adjustment part 33 of the recognition unit 30 (condensing position CP2), as shown in the area on the right side of the recognition area ER2 in FIG. 6(a) and the area on the right side of the recognition area ER3 in FIG. 6(d), visual information is shown such that a line thinner than the reference width can be seen. In FIGS. 6(a) and 6(d), for the sake of convenience, the lines formed by the image of the recognition unit 30 are shown as black lines, but actually, they are lines formed by retro - reflected light. Therefore, among the visual information, the part indicated by the thick line of the reference width is shown by strong light, and the part indicated by the thin line is shown by weak light. The closer the condensing position CP overlaps the adjustment part 33 on the left side, the thinner the line in the visual information becomes, and the lower the light intensity. The closer the condensing position CP overlaps the adjustment part 33 on the right side, the thicker the line in the visual information becomes, and the higher the light intensity. In the visual information, the area visually recognized as a predetermined shape (here, a line) due to the overlap of the condensing position CP and the recognition unit 30 may be referred to as the visual area 40.

[0037] Thus, when the light collecting position CP becomes the adjustment unit 33 depending on the observation angle θ, the corresponding location is indicated by weak light in the visual information. The recognition unit 30 has an adjustment unit 33 in a shape that changes the intensity of the light observable at the observation position according to the observation angle θ.

[0038] In order to change the intensity of the light observable at the observation position using the adjustment unit 33, the adjustment unit 33 uses a pattern structure in which light passes through the lens unit 22, forms a focus on the pattern transfer layer 21, and the size of the adjustment unit 33 is smaller than the size of the focus, so that the intensity of the light can be changed. Also, since the intensity distribution of the focused light when the light is focused has a Gaussian distribution or a normal distribution depending on the lens shape, the shape of the adjustment unit 33 can linearly change the intensity according to the measurement position by changing the pattern shape such as a curved shape according to the intensity distribution to be collected.

[0039] Note that the shape of the adjustment unit 33 is not limited to that shown in Fig. 4(a). For example, as shown in Fig. 4(b), an adjustment unit 33 having a curved shape may be adopted. Also, as shown in Fig. 4(c), an adjustment unit 33 having a trapezoidal shape may be adopted.

[0040] Next, with reference to Figs. 5 and 6, the relationship between the observation angle θ and the visual information will be described. Figs. 5 and 6 are enlarged views of the location indicated by "A1" in Fig. 3(a). Fig. 5(b) shows a state where the line of sight AX is perpendicular to the position recognition unit 3A (observation angle θ = 0°). At this time, as shown in Fig. 5(c), the light collecting position CP at each position overlaps with the recognition unit 30 only in the recognition region ER1 and does not overlap in the other recognition regions ER2, ER3, ER4,.... In this case, as shown in Fig. 5(a), in the visual information, a line of the reference width is displayed only at the location corresponding to the recognition region ER1.

[0041] Figure 5(e) shows a state where the line of sight AX is inclined to the right with respect to the position recognition unit 3A (the observation angle θ is positive to the right). At this time, as shown in Figure 5(f), the condensing position CP in the right region overlaps with the main body portions 32 of all the recognition units 30 in the recognition regions ER1, ER2, ER3, ER4,.... In this case, as shown in Figure 5(d), in the visual information, lines with a reference width are displayed at positions corresponding to all of the recognition regions ER1, ER2, ER3, ER4,.... As shown in Figure 5(f), the condensing position CP in the left region overlaps with the main body portion 32 of the recognition unit 30 in the recognition region ER1 and overlaps with the adjustment portion 33 of the recognition unit 30 in the recognition region ER2, and does not overlap in the other recognition regions ER3, ER4,.... In this case, as shown in Figure 5(d), in the visual information, a line with a reference width is displayed at the position corresponding to the recognition region ER1, a thin line is displayed at the position corresponding to the recognition region ER2, and no lines are displayed in the other recognition regions ER3, ER4,.... Further, Figure 5(h) shows a state where the line of sight AX is further inclined to the right with respect to the position recognition unit 3A (the observation angle θ is positive to the right). At this time, as shown in Figure 5(i), the condensing position CP in the left region overlaps with the main body portions 32 of the recognition units 30 in the recognition regions ER1 and ER2 and overlaps with the adjustment portion 33 of the recognition unit 30 in the recognition region ER3, and does not overlap in the other recognition regions ER4,.... In this case, as shown in Figure 5(g), in the visual information, lines with a reference width are displayed at positions corresponding to the recognition regions ER1 and ER2, a thin line is displayed at the position corresponding to the recognition region ER3, and no lines are displayed in the other recognition regions ER4,....

[0042] Figure 6(b) shows a state where the line of sight AX is inclined to the left with respect to the position recognition unit 3A (the observation angle θ is positive to the left). At this time, as shown in Figure 6(c), the condensing position CP in the left region overlaps with the main body portions 32 of all the recognition units 30 in the recognition regions ER1, ER2, ER3, ER4,.... In this case, as shown in Figure 6(a), in the visual information, lines with a reference width are displayed at positions corresponding to all of the recognition regions ER1, ER2, ER3, ER4,.... As shown in Figure 6(c), the condensing position CP in the right region overlaps with the main body portion 32 of the recognition unit 30 in the recognition region ER1 and overlaps with the adjustment portion 33 of the recognition unit 30 in the recognition region ER2, and does not overlap in the other recognition regions ER3, ER4,.... In this case, as shown in Figure 6(a), in the visual information, a line with a reference width is displayed at the position corresponding to the recognition region ER1, a thin line is displayed at the position corresponding to the recognition region ER2, and no lines are displayed in the other recognition regions ER3, ER4,.... Further, Figure 6(e) shows a state where the line of sight AX is inclined further to the left with respect to the position recognition unit 3A (the observation angle θ is positive to the left). At this time, as shown in Figure 6(f), the condensing position CP in the right region overlaps with the main body portions 32 of the recognition units 30 in the recognition regions ER1, ER2, ER3 and overlaps with the adjustment portion 33 of the recognition unit 30 in the recognition region ER4, and does not overlap in the other recognition regions above that. In this case, as shown in Figure 6(d), in the visual information, lines with a reference width are displayed at positions corresponding to the recognition regions ER1, ER2, ER3, a thin line is displayed at the position corresponding to the recognition region ER4, and no lines are displayed in the other recognition regions above that.

[0043] As described above, the position recognition unit 3A can indicate on which side the line of sight AX is tilted depending on whether all the lines are displayed in the left region or the right region. Further, the position recognition unit 3A can change the number of lines as the visual region 40 according to the observation angle θ with respect to the position recognition unit 3A from the observation position. Therefore, in the visual information, by counting the number of lines of the reference width, it becomes possible to grasp an approximate value of the observation angle θ. Also, the position recognition unit 3A changes the intensity of the light of the visual information observable at the observation position according to the observation angle θ with respect to the position recognition unit 3A from the observation position. That is, based on the intensity of the light of the lines thinner than the reference width, it becomes possible to grasp the detailed value of the observation angle θ. Note that the relationship between the number of lines and the observation angle θ, and the relationship between the intensity of the light of the thin lines and the observation angle θ may be measured in advance and stored in the arithmetic device 103 after being made into a database.

[0044] Next, the operation and effect of the marker 1 according to the embodiment of the present invention will be described.

[0045] The marker 1 is a marker 1 having a position recognition unit in which the visual information observed at the observation position changes according to the observation direction, and the position recognition unit 3 changes the intensity of the light of the visual information observable at the observation position according to the observation angle θ with respect to the position recognition unit 3 from the observation position.

[0046] The position recognition unit 3 of the marker 1 changes the intensity of the light of the visual information observable at the observation position according to the observation angle θ with respect to the position recognition unit 3 from the observation position. Such a change in the light intensity can be used as a parameter indicating a change in the minute observation angle θ by grasping the correspondence with the observation angle θ in advance. Also, the method of calculating the observation angle θ by grasping the change in the light intensity can reduce the process in which an accuracy deviation occurs compared to the method of calculating the observation angle by grasping the positional relationship of the patterns in the visual information (for example, the method of FIG. 8 described later). From the above, it becomes possible to recognize the position of the marker 1 with high accuracy.

[0047] First, for comparison with Marker 1 of the present embodiment, Marker 111 according to a comparative example as shown in FIG. 8 will be described. Marker 111 according to the comparative example has reference points 104 at the four corners of the main body 110, a position recognition part 113 (also refer to FIG. 7) between the reference points 104, and a mark part 112 at the center of the main body 110. A method of calculating the observation angle θ using such a marker 111 will be described. First, the arithmetic unit grasps the positions of the reference points from the image. In this step, in order to grasp the positions of the reference points, an accuracy deviation (for example, 0.25 mm) occurs. Next, the arithmetic unit grasps the position of the visual area 140 of the position recognition part 113 from the image. In this step, in order to grasp the position of the visual area 140, an accuracy deviation (for example, 0.25 mm) occurs. Next, the arithmetic unit measures the distance between the reference point 104 and the visual area 140. In this step, in order to measure the distance L1 between the two, an accuracy deviation (for example, 0.25 mm) occurs. Next, the arithmetic unit calculates the observation angle θ by replacing the measured distance information with the observation angle θ. Thus, when using Marker 111 according to the comparative example, an accuracy deviation occurs in three steps.

[0048] On the other hand, a method of detecting the observation angle θ using Marker 1 of the present embodiment will be described. First, the arithmetic unit 103 acquires an image of the visual information of the position recognition part 3A from the camera 102. Here, it is assumed that the visual information shown in FIG. 5(g) is obtained. First, since all the lines on the right side are visible, the arithmetic unit 103 determines that the observation angle θ is positive on the right side. Further, since there are two lines of the reference width on the left side, the arithmetic unit 103 determines that at least the observation angle θ is 2° or more in comparison with the database. In this step, since the arithmetic unit 103 only performs an operation of counting the number of lines, no accuracy deviation occurs. Next, the arithmetic unit 103 calculates the difference between the light intensity of the uppermost line (the line in the recognition area ER3) of the visible lines and the light intensity of the line one below (or the line of the reference width). In this step, based on the assumption of grasping the light intensity, there is a slight accuracy deviation (for example, 10 -9There may be room for (mm) to occur. The arithmetic unit 103 converts the obtained light intensity difference into information on the observation angle θ by comparing it with a database. In this process, since only the operation of the arithmetic unit 103 to convert the light intensity difference into angle information is performed, no accuracy deviation occurs. When the angle obtained from the light intensity difference is 1.75°, the arithmetic unit 103 calculates the observation angle θ by adding it to the observation angle θ obtained from the number of lines and performing the operation "2° + 1.75° = 3.75°". In this way, when using the marker 1, compared with the comparative example in FIG. 8, the number of times of accuracy deviation occurring during the process is small, and the accuracy deviation that occurs is also small. Therefore, by using the marker 1 of the present embodiment, the position of the marker 1 can be recognized with high accuracy.

[0049] The position recognition unit 3 may include a plurality of arranged lens units 22 and a recognition unit 30 formed on the back side of the lens unit 22 to form visual information. In this case, it can be a suitable configuration as the position recognition unit 3.

[0050] A plurality of recognition units 30 spaced apart from each other may be formed for each lens unit 22 of the recognition unit 30. Such a position recognition unit 3 can increase the amount of information obtained from the visual information compared to a position recognition unit 3 in which one recognition unit 30 is formed for each lens unit 22.

[0051] The recognition unit 30 may have a shape that changes the intensity of light observable at the observation position according to the observation angle θ. In this case, it is possible to easily change the intensity of light only by adjusting the shape of the recognition unit 30.

[0052] The position recognition unit 3 may include a retroreflective member 11 provided on the back side of the lens unit 22 and the recognition unit 30. In this case, in the visual information, the portion corresponding to the recognition unit 30 can be strongly illuminated by retroreflection. Therefore, it is possible to grasp the change in the intensity of light in a state where the influence of disturbance factors such as sunlight and dark places is reduced.

[0053] The position recognition unit 3 can display a plurality of visually distinguishable regions as visual information, and can change the number of the visual regions 40 according to the observation angle with respect to the position recognition unit 3 from the observation position, and can also change the light intensity of any one of the visual regions 40. Grasping the number of the visual regions 40 can be more easily performed than grasping the change in the light intensity of the visual regions 40. Therefore, it is possible to grasp the approximate observation angle θ based on the number of the visual regions 40, and to grasp the minute observation angle θ based on the change in the light intensity of the visual regions 40.

[0054] The marker 1 has a position recognition unit 3 in which the visual information observed at the observation position changes according to the observation direction. The position recognition unit 3 can display a visual region 40 shown in a predetermined display mode as visual information, and can change at least one of the shape and the number of the visual regions 40 observable at the observation position according to the observation angle θ with respect to the position recognition unit 3 from the observation position.

[0055] The position recognition unit 3 of the marker 1 changes the number (the number of lines) of the visual regions 40 observable at the observation position according to the observation angle θ with respect to the position recognition unit 3 from the observation position. Such a change in the number of the visual regions 40 can be used as an index indicating the change in the observation angle θ by grasping the correspondence with the observation angle θ in advance. In addition, the method of calculating the observation angle θ by grasping the change in the number of the visual regions 40 can reduce the processes in which accuracy deviation occurs compared with the method of calculating the observation angle by grasping the positional relationship of the patterns in the visual information (for example, the method in FIG. 8). From the above, it becomes possible to recognize the position of the marker with high accuracy.

[0056] In addition, in the marker 1 according to the present embodiment, the main body 10 is integrally formed including the position recognition unit 3. Also, the recognition unit 30 can also be integrally formed by molding. Therefore, since the position recognition function can be directly imparted to the molded part, alignment and the like can be made unnecessary, the number of parts can be reduced, and precise alignment and the like can be made unnecessary.

[0057] The present invention is not limited to the above-described embodiments.

[0058] For example, the position recognition unit 3 of the marker 1 may change the shape of the visual region 40 observable at the observation position according to the observation angle θ with respect to the position recognition unit 3 from the observation position. For example, a position recognition unit 3A as shown in FIG. 9 may be employed. FIG. 9(a) shows the pattern of the recognition unit 30, and FIG. 9(b) shows the shape pattern of the visual region 40 at “observation angle θ = 0°”. Thus, by complicating the arrangement of the recognition unit 30, the shape pattern of the visual region 40 changes depending on the observation angle θ.

[0059] Also, as shown in FIG. 10, it may be configured to indicate a number according to the shape of the visual region 40 according to the observation angle θ. Thus, when creating a shape that indicates a predetermined meaning like a number by the visual region 40, it becomes possible for the human eye to easily grasp the observation angle θ. Note that “A, B, C” in FIGS. 10(a), (d), and (g) and “A, B” in FIGS. 10(c), (f), and (i) indicate the positional relationship between the recognition unit 30 and the visual region 40. FIGS. 10(c), (f), and (i) show the shape pattern of the portion indicated by “A1” in FIGS. 10(a), (d), and (g).

[0060] As described above, the change in the shape of the visual region 40 can be used as an index indicating the change in the observation angle θ by grasping the correspondence with the observation angle θ in advance. Also, the method of calculating the observation angle θ by grasping the change in the shape of the visual region 40 can reduce the steps in which accuracy deviation occurs compared to the method of calculating the observation angle by grasping the positional relationship of the patterns in the visual information (for example, the method in FIG. 8). From the above, it becomes possible to recognize the position of the marker with high accuracy.

[0061] In the above-described embodiment, a sheet of the retroreflective member 11 is employed, but a retroreflective structure may be formed on the back surface of the main body 10.

[0062] Also, the retroreflective member 11 can be expected to have the same effect as long as it is a member that reflects.

[0063] Also, the retroreflective member 11 on the back side of the position recognition unit 3A may be omitted. In this case, a rough surface may be formed on the recognition unit 30 and a flat surface may be formed on the general unit 31 during molding. Alternatively, the recognition unit 30 may be formed by paint or the like. In this case, in the visual information, a line corresponding to the color of the recognition unit 30 is displayed as the visual area 40. When the condensing position CP overlaps with the adjustment unit 33 of the recognition unit 30, a line with a thickness at that position is displayed. For example, when the recognition unit 30 is black and the general unit 31 is white, the thin line can be regarded as a portion where the light intensity in the image is high compared to the line with the reference width. In this way, the position recognition unit 3A can change the light intensity according to the observation angle.

Explanation of Signs

[0064] 1 ··· Marker, 3, 3A, 3B ··· Position recognition unit, 11… Retroreflective member, 22… Lens unit, 30… Recognition unit, 40… Visual area.

Claims

1. A marker having a position recognition unit in which visual information observed at an observation position changes depending on an observation direction, the position recognition unit changes a light intensity of the visual information observable at the observation position in accordance with an observation angle from the observation position to the position recognition unit; The position recognition unit has a recognition unit that forms the visual information, The recognition unit is A body portion extending with a constant width; an adjustment unit that changes the intensity of light observable at the observation position in accordance with the observation angle; The adjustment portion is provided at one end of the main body portion, and has a width that narrows toward the one side, The position recognition unit is A plurality of lens portions arranged; A marker having a recognition portion formed on a rear side of the lens portion and forming the visual information.

2. The marker according to claim 1 , wherein a plurality of the recognition portions are formed spaced apart from each other for each of the lens portions.

3. The marker according to claim 1 or 2, wherein the position recognition unit has a retroreflective member provided on a rear side of the lens unit and the recognition unit.

4. A marker having a position recognition unit in which visual information observed at an observation position changes depending on the observation direction, the position recognition unit changes a light intensity of the visual information observable at the observation position in accordance with an observation angle from the observation position to the position recognition unit; The position recognition unit has a recognition unit that forms the visual information, The recognition unit is A body portion extending with a constant width; an adjustment unit that changes the intensity of light observable at the observation position in accordance with the observation angle; The adjustment portion is provided at one end of the main body portion, and has a width that narrows toward the one side, The position recognition unit is capable of displaying a plurality of visual areas spaced apart from each other as the visual information, A marker that changes the number of visual areas and changes the light intensity of any of the visual areas according to an observation angle from the observation position to the position recognition unit.

5. A marker having a position recognition unit in which visual information observed at an observation position changes depending on an observation direction, The position recognition unit is As the visual information, a visual area shown in a predetermined display mode can be displayed, changing at least one of a shape and a number of the visual areas observable at the observation position according to an observation angle from the observation position to the position recognition unit; The position recognition unit has a recognition unit that forms the visual information, The recognition unit is A body portion extending with a constant width; an adjustment unit that changes the intensity of light observable at the observation position in accordance with the observation angle; The adjustment portion is provided at one end of the main body portion, and has a width that narrows toward the one side, The position recognition unit is A plurality of lens portions arranged; A marker having a recognition portion formed on a rear side of the lens portion and forming the visual information.

Images