JP2011149908A - Calibration device for camera, and method for using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a calibration device for a camera reducing the load in production, transportation, an arrangement, or a removal even for a large calibration device, and a method for using the same, appropriately preventing reduction in accuracy due to a resolution of the camera, when arranging the calibration device at a distant place from the camera. <P>SOLUTION: The calibration device for a camera includes multiple calibration device pieces each formed into a sheet to have a polygonal shape in a plane view; the respective calibration device pieces include two or more different colors. Each of the calibration device pieces has a joint detachable from adjacent calibration device pieces on each of at least two sides of its polygonal shape; when the calibration device for a camera is used, the multiple calibration device pieces are assembled so as to have a checkered pattern; and the assemble pattern or a size can be changed as appropriate, according to spatial constraints or positional relationship with the camera. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a camera calibration lamp suitable for calibration of a camera for photographing a wide space and a method for using the same.

  It is difficult to accurately calibrate a camera that captures a wide space in order to obtain a positional relationship with the real space. In view of this, there is known a method of using a very large calibration lamp that fills the shooting area of a camera for calibrating a camera that shoots this kind of wide space. However, such a large calibration rod has a very heavy burden in its production, transportation, installation and removal. In view of this, a method has been proposed in which a plurality of calibration ceremonies are arranged in an imaging region, and the positional relationship between the plurality of calibration ceremonies is acquired from information such as the size and shape of the imaging calibrator and an external measuring instrument (for example, Patent Document 1, 2 or non-patent document 1).

JP 2002-22444 A JP 2008-193188 A

"A flexible new technology for camera calibration" IEEE Transactions on Pattern Analysis and Machine Intelligence, 22 (11): 1330-1334, 2000.

However, in the technique described in the prior art document, for example, an external measuring instrument may be necessary, or the calibration accuracy of the camera may be affected by the estimation accuracy of the positional relationship between a plurality of calibration ceremonies. is there. In addition, if the size or pattern of the calibration caliber is not appropriate for the resolution of the camera itself, the recognized calibration ceremonial pattern may become unclear, resulting in a decrease in the detection accuracy of feature points and calibration. There is a problem that the accuracy is lowered.
Therefore, the present invention has been made paying attention to such problems, and provides a camera calibration rod that can reduce the burden of production, transportation, installation, and removal even with a large calibration rod. Furthermore, it is an object of the present invention to provide a method for using a camera calibration lamp that can appropriately prevent a decrease in accuracy due to the resolution of the camera when the calibration lamp is arranged at a position away from the camera.

  In order to solve the above-mentioned problem, the first invention of the present invention is a calibration method for calibrating a camera based on correspondence between physical coordinates or relative coordinates of imaged feature points, and the planar view is a polygon. A plurality of plate-shaped calibration pieces that are formed in a shape and can be assembled to each other, and each calibration piece has a connecting portion that can be connected to and released from adjacent calibration pieces on at least two sides. It is characterized by having each.

  According to the camera calibration lamp according to the first aspect of the invention, the camera is calibrated based on the correspondence of the physical coordinates or relative coordinates of the captured feature points, so that no special external measuring instrument is required. And according to this camera calibration ritual, it is provided with a plurality of calibration ceremonies each having a connecting portion that can be connected to and released from adjacent calibration ceremonies, so that a large calibration ritual that is integrally formed is used. Instead, a large calibration lamp can be easily constructed by assembling and disassembling a plurality of calibration bars. Therefore, it can be installed in a state suitable for the place where the calibration is installed without being restricted by spatial constraints. In addition, since a plurality of calibration pieces can be assembled and disassembled with each other, the shape, size, or pattern in which the plurality of calibration pieces are assembled can be appropriately changed. Therefore, it is easy to manufacture, transport, install, and remove. For example, by assembling a plurality of calibration pieces according to the resolution of the camera itself or the detection accuracy of the feature points, the size and pattern of the calibration are set appropriately. be able to.

Here, in the camera calibration ritual according to the first aspect of the invention, it is preferable that the calibration ceremonial piece has a square shape or a regular hexagonal shape. Such a configuration is suitable as a polygonal shape for assembling and disassembling a plurality of calibration pieces.
Further, in the camera calibration ceremonies according to the first invention, the plurality of calibration ceremonies are composed of a plurality of types of calibration ceremonies having different surface brightness or saturation, and the feature points are the plurality When assembling a type of calibration strip, it is preferably formed by the difference in brightness or saturation between adjacent calibration strips. With such a configuration, it is preferable to use an intersection formed by adjacent calibration strips as a calibration feature point, depending on the shape, size, or pattern in which a plurality of calibration strips are assembled. Various feature points for calibration can be set.

  Further, in the camera calibration ritual according to the first invention, the calibration ceremonial piece comprises a fitting part having a concave part or a convex part that can be detachably connected to the adjacent calibration ceremonial piece, When a plurality of calibration strips are assembled, it is preferable to have a concealing structure that hides the fitting portion when viewed from the camera side. Such a configuration is suitable for avoiding the influence of the shadow caused by the fitting portion when recognizing the feature point for calibration when the connecting portion is constituted by the fitting portion.

  In the camera calibration lamp according to the first aspect of the present invention, it is preferable that the calibration lamp piece includes a figure or pattern for representing position information, or position information display means such as a light emitting portion or a reflector. With such a configuration, the coordinates of the light source, figure, or pattern projected onto the light emitting part or reflector in the captured image can be identified efficiently, so the calibration work is more efficient in calibrating the positional relationship with the camera. Can be performed.

  In the camera calibration lamp according to the first invention, the calibration lamp piece includes the position information display means, and further includes an RF tag or a GPS receiver as the position information holding means for holding the position information. It is preferable. With such a configuration, it is not necessary to acquire the positional relationship between the calibration caliber from the size and shape of the assembled calibration caliber using a special external measuring instrument, and the calibration accuracy of the camera is affected by the estimated accuracy of the positional relationship. There is no risk of receiving it.

  Furthermore, in order to solve the above-mentioned problem, a second invention of the present invention is a method for using a camera calibration rod used for camera calibration and having a calibration feature point. Using the camera calibration ceremony, the shape, size, or pattern of the assembled calibration ceremonies is changed according to the position with the camera so that the feature points of the recognized calibration ceremonies become clear. It is characterized by that.

  According to the method for using the camera calibration ceremonies according to the second invention, the camera calibration ceremonies according to the first invention are used. Depending on the position of the calibrator, the feature point of the recognized calibration ceremony is changed so that it is clear.When placing the calibrator away from the camera, the pattern and size can be changed appropriately. A reduction in accuracy due to the resolution of the camera can be prevented.

Further, since the camera calibration ceremonies according to the first invention can freely change the pattern of the calibration ceremonies by combination, in the method for using the camera calibration ceremonies according to the second invention, the plurality of calibration ceremonies If this combination is changed according to the place where this is installed, it can be installed in a state suitable for the place where the calibration is installed without being restricted by spatial constraints.
Further, in the method for using the camera calibrator according to the second aspect of the invention, when assembling the plurality of calibration ceremonies, those having mutually different colors are used, and the calibration ceremonies are recognized by locations adjacent to each other. If the characteristic points are formed, the camera can be calibrated at the same time while calibrating the positional relationship with the camera by photographing the calibration with the camera. Moreover, when using the intersection formed by the adjacent calibration pieces as the calibration feature points, the intersection can be further clarified.

  As described above, according to the present invention, even for a large calibration lamp, a camera calibration lamp can be provided that can reduce the burden of production, transportation, installation, and removal, and further, calibration is performed at a position away from the camera. It is possible to provide a method for using a camera calibration rod that can appropriately prevent a decrease in accuracy due to the resolution of the camera when arranging the rod.

It is a perspective view for demonstrating 1st embodiment of the calibration lamp for cameras which concerns on this invention. It is explanatory drawing ((a) is a left view, (b) is a front view, (c) is a right view, (d) is a bottom view) of the calibration piece (triangle shape) used for 1st embodiment. . It is explanatory drawing ((a) is a left view, (b) is a front view, (c) is a right view, (d) is a bottom view) of the calibration piece (triangle shape) used for 1st embodiment. . It is explanatory drawing ((a) is a left view, (b) is a front view, (c) is a right view, (d) is a bottom view) of the calibration piece (triangle shape) used for 1st embodiment. . It is explanatory drawing ((a) is a left view, (b) is a front view, (c) is a right view, (d) is a bottom view) of the calibration piece (triangle shape) used for 1st embodiment. . It is a perspective view for demonstrating 2nd embodiment of the camera calibration lamp | ramp which concerns on this invention, The figure (a) is the 1st example of the combination pattern of the calibration lamp piece, (b) is a 2nd example. (C) is a third example (an example in which the calibration of the positional relationship with the camera and the color calibration of the camera can be performed simultaneously). Explanatory drawing ((a) is a top view, (b) is a left view, (c) is a front view, and (c) is an explanatory view of a calibration piece (rectangular shape (a structure in which the fitting portion is hidden when assembled)) used in the second embodiment. (D) is a right side view, and (e) is a bottom view). Explanatory drawing ((a) is a top view, (b) is a left view, (c) is a front view, and (c) is an explanatory view of a calibration piece (rectangular shape (a structure in which the fitting portion is hidden when assembled)) used in the second embodiment. (D) is a right side view, and (e) is a bottom view). Explanatory drawing ((a) is a top view, (b) is a left view, (c) is an explanatory view of the other example (structure assembled through a connection member) of the calibration piece (rectangular shape) used for 2nd embodiment. (D) is a right side view, (e) is a bottom view). It is explanatory drawing of the connection member used for the modification of the calibration piece (rectangular shape) used for 2nd embodiment, The figure (a) is the front view, (b) is a side view, (c) is a bottom face. FIG. It is a top view for demonstrating 3rd embodiment of the calibration lamp for cameras which concerns on this invention. It is explanatory drawing of the calibration ceremonial piece (hexagon shape) used for 3rd embodiment, the same figure (a) is the top view, (b) is the A arrow view in (a), (c) is ( It is a B arrow view in a). It is a perspective view of 4th embodiment of the camera calibration lamp | ramp which concerns on this invention. Explanatory drawing ((a) is a top view, (b) is a left view, (c) which is a rectangular shape (structure which comprises a light emission part and a fitting part is hidden when assembled)) used for 4th embodiment. ) Is a front view, (d) is a right side view, and (e) is a bottom view). Explanatory drawing ((a) is a top view, (b) is a left view, (c) which is a rectangular shape (structure which comprises a light emission part and a fitting part is hidden when assembled)) used for 4th embodiment. ) Is a front view, (d) is a right side view, and (e) is a bottom view).

Hereinafter, a first embodiment of the present invention will be described with reference to the drawings as appropriate. FIG. 1 is a perspective view for explaining a first embodiment of a camera calibration ceremony according to the present invention, and FIGS. 2 to 5 are calibration ceremonial pieces (triangular shapes) used in the first embodiment. ).
First, the configuration of the camera calibration lamp of the first embodiment will be described.
As shown in FIG. 1, the calibration rod 301 includes plate-shaped calibration rods 101, 201, 151, and 251 that are formed in a triangular shape in plan view.

Specifically, as shown in FIGS. 2 to 5, in the first embodiment, a calibration ceremonial member 301 is configured from four types of calibration ceremonial members 101, 201, 151 and 251. Each calibration piece 101, 201, 151 and 251 is made of a foamed resin. The material of each calibration strip is not limited to this, and for example, wood, hard plastic, metal or the like may be used.
Each of the calibration strips 101, 201, 151, and 251 is a plate-like member that is formed in a triangular shape (in this example, a right isosceles triangle) in plan view (see each front view (b)). As shown in FIGS. 2 and 4, the two calibration pieces 101 and 201 have a white surface color, and as shown in FIGS. 3 and 5, the other two calibration pieces 1151 are used. 251 and 251 are black on the surface. In addition, it is good to perform a matte process to the surface as needed.

  Each of the calibration strips 101, 201, 151, and 251 has a known triangle shape dimension, and the corresponding side dimensions are all equal (in the example of this embodiment, two pieces sandwiching a right angle). Are 20 cm each). Each of the calibration strips 101, 201, 151, and 251 is formed on each side with a fitting portion that can be fitted and removed with an adjacent calibration strip (see FIG. 1) in an assembled state. .

  In the example of this embodiment, the fitting portions on each side are the two sides 111 and 112 and 161 and 162 sandwiching the right angle as shown in FIGS. 2 and 3 for the calibration piece 101 and the calibration piece 151. The three fitting portions T are equally arranged along each side. Each fitting part T is formed in the trapezoid shape which consists of a convex part, and is attached with the attitude | position which orient | assigned the trapezoid-shaped lower base (wide side) side to the outer side. In addition, in the remaining sides 113 and 163, one fitting portion U is formed at the center of each side. The fitting portion U is formed in a trapezoidal shape including a concave portion, and is drilled in a posture in which the upper base (side having a narrow width) side of the trapezoidal shape faces outward.

  As shown in FIGS. 4 and 5, the calibration strips 201 and 251 are also formed with fitting portions that can be fitted to and detached from adjacent calibration strips (see FIG. 1) on each side. . In other words, the fitting portions on each side of the calibration strips 201 and 251 have three fitting portions U arranged equally on each of the two sides 211, 212, and 261, 262 that sandwich the right angle. . Each fitting portion U is formed in a trapezoidal shape composed of a concave portion, which is formed so as to be detachable with almost no gap with respect to the three convex fitting portions T of the calibration piece 101 and the calibration piece 151. Yes. Further, the remaining sides 213 and 263 are formed by a single fitting portion T formed in a trapezoidal shape including a convex portion that can be fitted and removed with almost no gap with respect to the fitting portion U of the concave portion of the sides 113 and 163. It is formed at the center of each side. When fitting and disengaging with the adjacent calibration strips, each calibration strip 101, 201, 151 and 251 is easily slid with the adjacent calibration strip by sliding along the thickness direction of the plate. Can be connected to and disconnected from each other. And in directions other than the thickness direction of a board, since a movement is restrained by the fitting structure formed in the trapezoid shape as mentioned above, the connected state is maintained (henceforth below). The same in other examples).

Next, the function and effect of the calibration rod 301 of the first embodiment, the method of using the calibration rod 301, and the function and effect thereof will be described.
When using the calibration rod 301 according to the first embodiment, the shape, size, or pattern of the above-described plurality of calibration rods 101, 151, 201, and 251 is set as the place where the calibration rod 301 is installed, the camera 302, or the like. Change appropriately according to the position.
In the example of the present embodiment, first, the white calibration strips 101 and 201 are combined with the sides 113 and 213 into a rectangular shape (in this example, a square of 20 cm square), and a black calibration strip 101 is also formed. The ceremonial pieces 151 and 251 are formed into a rectangular shape by combining the sides 163 and 263 with each other. Next, as shown in FIG. 1, the three calibration fitting pieces 101, 151, 201, and 251 of the rectangular calibration piece set are combined with each other. This constitutes a checkered pattern in which white and black are alternately arranged.

  Then, when the camera 302 is calibrated with the calibration stylus 301, the calibration stylus 301 is photographed by the camera 302, and as shown in FIG. (I = 101 to 109). The feature point Pi is detected by image processing such as corner detection, and the camera 302 can be calibrated by associating it with physical coordinates (or relative coordinates).

  Thus, according to the calibration rod 301 according to the first embodiment, a plurality of fitting portions U and fitting portions T each having a fitting portion U and a fitting portion T as a connecting portion that can be connected to and released from the adjacent calibration piece. Since the calibration strips 101, 151, 201, and 251 are provided, the shape, size, or pattern of the assembled calibration strips 101, 151, 201, and 251 is recognized according to the position with the camera 302. The feature point Pi of the proofreading lamp 301 can be changed so as to be clear. Therefore, when the calibration stylus is arranged at a position away from the camera 302, it is possible to appropriately prevent a decrease in accuracy due to the resolution of the camera by appropriately changing the pattern and size.

Moreover, according to the calibration ceremonial rod 301 according to the first embodiment, the combination of a plurality of calibration ceremonial strips can be freely changed depending on the place where the calibration ceremonial strip is installed. Can be installed in a state suitable for the location.
In other words, in an actual space, there are usually cases where things such as desks and shelves that require time and effort are installed, but calibration is performed by appropriately combining the above-mentioned calibration pieces 101, 151, 201, and 251. By configuring the rod 301, it is possible to easily install the calibration rod 301 having a large checkered pattern on the floor surface while eliminating the need to move an object that requires labor to remove a desk, a shelf, or the like. Thereby, many feature points Pi are easily obtained, and the accuracy of calibration of the camera 302 is improved.

In addition, according to the calibration rod 301 according to the first embodiment, each of the calibration rods 101, 151, 201 and 251 has a known dimension of a polygonal shape (right isosceles triangle in this example). The shape, size or pattern in which the calibration piece is assembled is also known. Therefore, a special external measuring instrument can be dispensed with.
In addition, according to the calibration lamp 301 according to the first embodiment, when assembling the plurality of calibration lamp pieces 101, 151, 201 and 251, those having mutually different colors (white and black) are arranged adjacent to each other. Since the pattern is formed, the calibration feature point Pi can be easily formed. Also, by arranging adjacent colors (white and black) adjacent to each other, the feature point Pi for calibration uses the intersection point formed by the adjacent calibration pieces, and the intersection point (feature point Pi). ) Becomes clearer.

  Note that the camera calibration lamp and the method of using the same according to the present invention are not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. For example, in the example of the first embodiment, as an example in which different colors (white and black) are arranged adjacent to each other, a pair of triangular calibration proofing pieces of the same color are made adjacent to each other in a rectangular shape, and these are further combined However, the camera calibration ceremonies according to the present invention are not limited to this, for example, the calibration ceremonies are rectangular as in the calibration ceremonies according to the second embodiment described below. It is good.

Hereinafter, a second embodiment of the calibration lamp according to the present invention will be described with reference to FIGS.
A calibration lamp 501 according to the second embodiment shown in FIG. 6A includes a calibration lamp 451 having a black surface and a calibration lamp 451 having a white surface. As shown in FIGS. 7 and 8, the calibration strips 401 and 451 according to the second embodiment are formed in a rectangular shape (in this example, a rectangular shape) in plan view (see front view (c)). This is different from the first embodiment. The dimensions of each rectangular shape are known, and each side has a fitting portion that can be fitted to and detached from an adjacent calibration strip.

  Specifically, as shown in FIGS. 7 to 8, the calibration strip 401 is provided with convex fitting portions T similar to those in the first embodiment on the sides 411 and 412 along the sides. Concave fitting portions U similar to those of the first embodiment are equally arranged on the sides 413 and 414 along each side. Similarly, in the calibration piece 451, convex fitting portions T that are convex on the sides 461 and 462 are equally arranged along each side, and concave fitting portions U on the sides 463 and 464 are provided on each side. It is equally distributed along. Then, by combining the concave fitting portions U and the convex fitting portions T of the calibration pieces 401 and 451 with each other, a calibration rod 501 having a checkered pattern as shown in the example of FIG. Can be done. The shape of the calibration strip shown in FIGS. 7 and 8 is also an example, and various rectangular shapes such as a square or a parallelogram can be used.

  Here, each calibration piece 401 and 451 is provided with a concealing structure S in which the fitting portions T and U on each side are hidden when viewed from the camera side when a plurality of calibration pieces are assembled. . Specifically, the concealing structure S of the present embodiment is configured by using the concave fitting portion U as a blind hole. That is, the concave fitting portion U is not formed so as to penetrate in the plan view direction, and the plane portion (S) remains on the surface facing the camera. With such a configuration, in addition to the operational effects of the first embodiment, even if the convex fitting portion T is fitted to the concave fitting portion U, the concealing structure S can be seen from the camera side. Since the visual recognition is blocked by the surface, when the feature points for calibration are recognized, the fitting portions T and U fitted to each other are not captured from the camera side. Therefore, it is suitable for avoiding the influence of shading by the fitting portions T and U.

  Also, the checkerboard pattern to be configured is not limited to the above embodiment, and the pattern can be changed by various combinations. For example, according to the camera calibration ceremony and the method of using the same according to the present invention, when the calibration ceremonial 301 is arranged at a position away from the camera 302, as in a modification example (calibration ceremony 1001) shown in FIG. It is preferable to increase the checkered pattern interval by combining the calibration pieces so that two pairs of the same colored calibration pieces are adjacent to each other. If such a combination is adopted, the pattern interval is set in consideration of the resolution of the camera 302 or the detection accuracy of the feature points, which is preferable in preventing a decrease in accuracy due to the resolution of the camera 302.

  Also, different colors are not limited to white and black, and various colors and combinations thereof can be employed. Specifically, for example, as in a modification example (calibration ceremony 1051) shown in FIG. 6C, the calibration ceremonial piece R whose surface is red, the calibration ceremony G whose surface is green, and the surface is blue. A checkered pattern can be formed by combining a certain calibration strip B with the calibration strip (451) having a white surface. And when this is image | photographed with the camera 302 and the picked-up image is isolate | separated into R component, G component, and B component, the checkered pattern corresponding to each component can each be acquired as a light and dark checkered pattern.

  Therefore, even if such a combination of calibration pieces is employed, it is possible to easily obtain feature points, and based on this, the camera can be calibrated as in the first embodiment. And if it is such a structure, in addition to the effect of said 1st embodiment, color calibration of the camera 302 can be performed simultaneously while calibrating the positional relationship with the camera 302. FIG. Of course, the shape of the calibration rod, the surface color, and the RGB component separation method shown in FIG. 6C are also examples, and the shape and surface of the calibration rod other than this example are not deviated from the gist of the present invention. The color and RGB component separation methods can be employed.

Further, the connection part of the calibration ceremonies constituting the calibration ceremonies is not limited to the above embodiment, and various forms can be adopted as long as they can be connected to and released from the adjacent calibration ceremonies. is there.
For example, as shown in FIG. 9, the calibration piece 601 according to the modification of the second embodiment has only a concave fitting portion U as a connecting portion that can be fitted to and detached from the adjacent calibration piece on each side. Are formed (equally arranged at three locations on each piece in this example). And the fitting part U of each edge | side is connected via the connection member 701 shown in FIG.

  In other words, the connecting member 701 is a member that constitutes a connecting portion that can be connected to and released from the adjacent calibration piece, and has two shapes R similar to those of the fitting portion T described above. It is a combined structure. Accordingly, the calibration rod can be assembled by fitting the connecting member 701 into the concave fitting portion U between the adjacent calibration rod pieces 601. Then, according to the calibration ceremony according to this modification, for example, a plurality of types of calibration ceremonial pieces 601 having different surface colors are appropriately used and assembled to a desired size via the connecting member 701, as shown in FIG. A checkered pattern can be configured in the same manner as the second embodiment described above. In addition, other functions and effects are the same as those in the second embodiment.

  In the above-described embodiment, the calibration feature point has been described as an example configured by the cooperation of adjacent calibration pieces. However, the feature point is not limited to this, and the feature point is provided on the surface of one calibration piece. Of course, it is also possible to provide them. For example, FIG. 11 to FIG. 12 show a third embodiment of the calibration lamp according to the present invention as another example of a calibration lamp piece having such a feature point and having a polygonal shape in plan view. The description will be given with reference as appropriate.

  As shown in FIG. 11, the calibration rod 1081 according to the third embodiment is composed of a plurality of calibration rods 801 formed in a hexagonal shape in plan view, and FIG. And, as shown in FIG. 12, the calibration piece 801 according to the fourth embodiment is different from the above-described embodiment in that the surface of one calibration piece is color-coded in two colors. In the example of the figure, the surface is divided into four areas by a line segment connecting the upper and lower vertices and a line segment connecting the upper left and right vertices in the horizontal direction, and this is colored in a checkerboard pattern in advance.

In the calibration rod 1081 according to the third embodiment, each side has a fitting portion (T, U) that can be fitted to and detached from an adjacent calibration rod piece, and the concave portion and the convex portion are alternately arranged. It is formed one by one. That is, in this example, the fitting part of each side is a fitting part U in which three sides 811, 813 and 815 are concave among the six sides, and the remaining three sides 812, 814 and 816 are convex fitting parts. T.
Then, by combining the concave fitting portion U and the convex fitting portion T of the calibration piece 801 adjacent to each other, a checkerboard pattern as shown in FIG. Thereby, like each embodiment mentioned above, this is image | photographed with a camera, the feature point P'i (i = 201-206) is detected by image processing, such as a corner detection, and a camera is matched, and a physical coordinate is matched. Can be calibrated. Other functions and effects are the same as those of the first to second embodiments.

In addition, the configuration according to the present invention includes a light emitting unit 1111 or 1161 as position information display means at the center of the surface of the calibration symbol 1101 or 1151, as in the fourth embodiment shown in FIGS. be able to. Note that the example of the fourth embodiment is different from the example of the second embodiment only in having a light emitting unit.
That is, in the fourth embodiment, by combining the calibration fitting 1101 whose surface is black and the concave fitting portion U and the convex fitting portion T of the calibration piece 1151 whose surface is white, A component 1201 having a checkered pattern as shown in FIG. 13 is formed. Accordingly, the information such as the color, brightness, blinking pattern, etc. corresponding to each light emitting unit is set in advance from the position of the light emitting unit Pi (i = 301 to 316) of each calibration piece, thereby configuring The checkerboard pattern of the light 1201 is photographed with a camera, and the physical coordinates of the light emitting unit Pi (i = 301 to 316) are based on information such as the color, brightness, and blinking pattern of the light emitting unit Pi (i = 301 to 316). Alternatively, relative coordinates can be specified. Since the relative coordinates of the feature point P′i (i = 351 to 359) of the component 1201 can be specified, it is possible to calibrate the camera.

  As described above, if each calibration strip includes a figure or pattern for representing its own position information, or position information display means such as a light emitting unit or a reflector as a feature point, the operation of each embodiment described above. In addition to the effect, when the feature point is recognized, the recognition becomes easier. Further, for example, even in a dark room, only one light emitting unit Pi (i = 301 to 316) is made to emit light one by one in order, and is photographed with the camera each time, and from the arrangement information of the light emitting unit Pi (i = 301 to 316) It is also possible to calibrate the camera by obtaining each physical coordinate and associating each physical coordinate with the coordinates of the light emitting unit Pi (i = 301 to 316) in the captured image of the camera.

  The arrangement positions of the light emitting units shown in FIGS. 14 and 15 are only examples, and other arrangement positions of the light emitting units can be used without departing from the gist of the present invention. Further, the position information display means is not limited to the light emitting unit, but a reflective material is attached, or a mark having a different shape or color such as a triangle or a quadrangle, or a two-dimensional code such as a barcode or QR code is attached. Can be configured. Here, the position information display means is a light source that projects onto the light emitting part or reflecting material, or a light source that projects the color, brightness, or blinking pattern of the figure or pattern onto the light emitting part or reflecting material, or the figure or pattern. It is preferable to be associated with absolute coordinates or relative coordinates. Such a configuration is suitable for efficiently specifying the coordinates of the light source, figure, or pattern projected on the light emitting part or the reflecting material in the photographed image.

  Furthermore, each calibration piece or any one of the calibration pieces can be provided with an RF tag or GPS so as to be paired with the position information display means. For example, the light emitting part or reflector of each calibration lamp is made to emit only one light in order, and each time it is taken with a camera, the RF tag or GPS receiver position information that is paired with the light emitting part emitting light at the same time By acquiring, it is possible to acquire physical coordinates without having the arrangement information of the light emitting units. If equipped with an RF tag or GPS receiver, they themselves function as position information holding means for holding position information. Therefore, it is also necessary to acquire the positional relationship between the calibration instruments from the external measuring instrument and the size and shape. In addition, there is no possibility that the calibration accuracy of the camera is affected by the estimation accuracy of the positional relationship.

301, 501, 1001, 1051, 1081, 1201 Calibration rod 101, 151, 201, 251, 401, 451, 601, 801, 1101, 1151 Calibration rod 302 Camera T (convex) fitting portion (connecting portion)
U (concave) fitting part (connecting part)
S concealment structure 1111, 1161 Light emitting part (position information display means)
Pi, P'i feature points

Claims (8)

  A calibration ritual that calibrates a camera based on correspondence between physical coordinates or relative coordinates of imaged feature points, and a plurality of plate-like calibration ceremonial pieces that are formed in a polygonal shape in plan view and can be assembled with each other. Each of the calibration strips has a connecting portion on at least two sides that can be connected to and released from adjacent calibration strips.   The plurality of calibration strips are composed of a plurality of types of calibration strips having different surface brightness or saturation, and the feature points are adjacent calibrations when the plurality of types of calibration strips are assembled. 2. The camera calibration lamp according to claim 1, wherein the camera calibration lamp is formed by a difference in brightness or saturation between the lamp pieces.   The calibration piece comprises a fitting portion having a concave portion or a convex portion that can be fitted and removed with an adjacent calibration piece, and when the plurality of calibration pieces are assembled, The camera calibration lamp according to claim 1, further comprising a concealing structure that conceals the fitting portion when viewed from above.   4. The calibration piece includes a figure or pattern for representing position information, or position information display means such as a light emitting part or a reflecting material as the feature point. The camera calibration lamp according to the item.   5. The camera calibration lamp according to claim 1, wherein the calibration lamp piece includes an RF tag or a GPS receiver as position information holding means for holding position information. .   6. A method of using a camera calibration ritual having a calibration feature point used for camera calibration, wherein the plurality of calibrations are performed using the camera calibration ceremony according to claim 1. A method for using a camera calibrator, wherein the shape, size, or pattern in which a ceremonial piece is assembled is changed according to the position with the camera so that the feature points of the recognized calibration ceremonies become clear.   7. The method for using a camera calibration lamp according to claim 6, wherein a combination of the plurality of calibration lamps is changed in accordance with a place where the lamp is installed.   8. When assembling the plurality of calibration ceremonial pieces, those having mutually different colors are used, and characteristic points of the calibration ceremonies that are recognized by places adjacent to each other are formed. How to use the camera calibration lamp described.

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