JP2008089362A - Pointer for camera position analysis used for photogrammetry - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pointer for camera position analysis used for photogrammetry and capable of performing highly accurate and ideal camera position analysis by three-dimensionally arranging points and setting reference scales for analysis in three-dimensional directions, easily and accurately indicating the points by visual estimation, and setting even eight points. <P>SOLUTION: The pointer for camera position analysis is provided with a frame 1 made of a rod material in a rectangular parallelepiped shape. Spheres 2 having centers at eight corner parts of the frame are mounted as points. The distances L1 between the points of the spheres adjacent to each other in width directions, the distances L2 between the points of the spheres adjacent to each other in depth directions, and the distances L3 between the points of the spheres adjacent to each other in vertical directions are each set as the reference scales. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a camera position analysis pointer used for photo measurement for measuring the shape of terrain, structures, and the like.

2. Description of the Related Art Conventionally, there has been known a photo measurement technique for measuring terrain and the shape of a structure based on a photographic image taken by a camera (digital camera).
For example, taking the case of measuring the topography of a landslide site as an example, the landslide site where there is a risk of a secondary disaster will not allow people to enter, so acquire the 3D coordinates of the camera position. Therefore, it is necessary to take a picture from a position away from the landslide site.

In such a case, a reference scale member serving as a reference for the length is arranged between the measurement site and the camera, and the measurement site is photographed from two different positions so as to capture the reference scale member. .
Next, the photographed photograph image is taken into the photograph measurement software of the computer, and eight or more identical points are designated on the two photograph images to analyze the camera position.
At this time, the same eight or more points to indicate indicate the feature point of the measurement site (for example, stone, rubble, corner of structure, etc.) and the point provided on the reference scale member, and the distance between these points is indicated. This is input to the photo measurement software as a reference scale, and the camera position can be analyzed based on this.
Finally, on the two photographic images, measurement can be performed by instructing the same feature points at the measurement site, and as described above, the camera position analysis is performed while the distance is constrained. Therefore, it can be measured at an actual distance.

Conventionally, as a reference scale member used for photo measurement as described above, there are two columnar members connected in an L-shape with points by discs equidistantly spaced, and the distance between these points as a reference scale. It is known (see Patent Document 1).
Since this reference measure is formed in an L shape by two columnar members, the points can be arranged only two-dimensionally (plane), and the reference measure is also set in the two-dimensional direction.

In order to improve the accuracy of photo measurement, it is necessary to accurately analyze the camera position. For this purpose, the points are arranged in three dimensions (solid) in the left-right direction, the front-rear direction, and the up-down direction. Thus, it can be said that it is ideal to set a reference scale for analysis in a three-dimensional direction.
For this reason, there has been a problem that a highly accurate analysis cannot be performed with a reference scale that can only be set in a two-dimensional direction as in the prior art.

  In addition, since the point of the conventional reference scale member is provided at the center of the disk, the disk is often displayed in an oval shape on the photographic image, and the point set at the center is visible. There is a problem that it is difficult to specify the point accurately when instructing with.

In order to improve the accuracy of photo measurement, at least 8 points are required. However, depending on the measurement site, there may be few feature points to be set as the base point. There was also a problem that the above points could not be found and photography had to be redone.
JP 2000-111342 A

  In the present invention, by arranging the points in three dimensions (solid) and setting the reference scale for analysis in the three-dimensional direction, ideal camera position analysis can be performed with high accuracy, It is an object of the present invention to provide a camera position analysis pointer that can be used for photo measurement in which instructions by registration can be easily and accurately set, and in addition, eight points can be set.

In order to solve the above problems, the camera position analysis pointer of the present invention (Claim 1)
It is provided with a frame formed in a rectangular shape with a rod, and a sphere with the center as a point is attached to the corners of the eight places of this frame, the distance between the points of the spheres adjacent to the left and right, and the spheres adjacent to the front and back The distance between the points and the distance between the points of the spheres adjacent in the vertical direction are set as reference scales.

The camera position analysis pointer of the present invention (Claim 2) is the camera position analysis pointer according to Claim 1,
A level device for measuring the horizontal posture of the camera position analysis pointer and an adjuster for adjusting the camera position analysis pointer to the horizontal posture are provided.

  The pointer for camera position analysis of the present invention (Claim 1) is a sphere attached to eight corners of a rectangular frame, and the distance between the points of adjacent spheres on the left and right is the center of the sphere. The point-to-point distance between adjacent spheres and the point-to-point distance between adjacent spheres are characteristically set as reference scales.

As described above, since the rectangular frame is used, the points can be arranged three-dimensionally (three-dimensional), and the reference scale for analysis can be set in the three-dimensional direction. Camera position analysis.
Further, eight points can be set by the spheres attached to the eight places, and the point is provided at the center of the sphere, so that the point can be easily and accurately indicated even if it is a visual register.

  In addition, the camera position analysis pointer of the present invention may need to be installed horizontally in some cases, for example, when the coordinate system is converted. In this case, the horizontal position is adjusted by the adjuster while checking the level with a leveling device. (Claim 2).

FIG. 1 is a perspective view showing a camera position analysis pointer of the first embodiment.
The pointer A for camera position analysis includes a frame 1 formed in a rectangular shape with a bar 10 (in the specification, a bar 10 is collectively referred to), and eight corners of the frame 1 And eight spheres 2 attached to the part.

The frame 1 is composed of four bars 10a that extend in the left-right direction, four bars 10b that extend in the front-rear direction (depth direction), and four bars that extend in the vertical direction. A total of twelve bars 10 with the material 10c are formed into a rectangular frame.
In this case, the front frame shape, the side frame shape, and the planar frame shape may be square or rectangular, or may be framed in a cubic shape in which the frame shapes of all surfaces are square.

  The sphere 2 is attached to eight corners of the frame 1, with the center as a point, a point-to-point distance L1 between spheres adjacent to the left and right, and a point-to-point distance L2 between spheres adjacent to the front and rear The distance L3 between the points of the spheres adjacent vertically is set as a reference scale.

In addition, although the material of the said rod 10 and the spherical body 2 is excellent in weather resistance, such as a plastic and a light metal, and a lightweight thing is preferable, it is not limited to this.
In addition, the color, diameter, and length of the bar 10 and the color, diameter, and color of the sphere 2 can be appropriately determined. Usually, the bar 10 is colored in a conspicuous color on the photographic image and has no trouble in carrying. It is formed in such a size.

A procedure for performing photo measurement using the camera position analysis pointer A will be briefly described.
First, the camera position analysis pointer A is placed between the measurement site and the camera, and the measurement site is photographed from two different positions so that the camera position analysis pointer A is captured.
Next, the photographed photographic image is taken into the photographic measurement software of the computer, and the center point of each of the eight spheres 2 on the two photographic images is instructed by registering.
Next, inter-point distances L1, L2, and L3 are input, and the camera position analysis is performed in a state in which the distances are constrained. In this way, the inter-point distances L1 in the left-right direction, the front-rear direction, and the up-down direction, Since L2 and L3 are input, ideal camera position analysis can be performed with high accuracy.
Thereafter, the distance between two points to be actually measured can be measured by instructing the same feature points at the measurement site on the two photographic images.

Note that the number of camera position analysis pointers A can be one for photo measurement, but when the measurement site (subject) is far away, the distance and angle between the cameras should be increased more accurately. can do.
In this case, since the camera position analysis pointer A appears small on the photographic image, the distance between the points becomes too close, and the calculation may not be performed correctly. In addition, it is preferable that the points for analysis are uniformly reflected in the entire photographic image in consideration of distortion of the photographic image. In order to compensate for this, it is preferable to install the camera position analysis pointers A at a plurality of locations.
However, when the measurement site (subject) is a short distance or when the accuracy may be rough, it is sufficient to install the camera position analysis pointer A at one location.
Further, when the camera position analysis pointers A are installed at a plurality of locations, it is sufficient that the camera position analysis pointers A are reflected in the photographic image, and the horizontal and distance between the camera position analysis pointers A and A are taken into consideration. There is no need.

Next, FIG. 2 is a perspective view showing a camera position analysis pointer of the second embodiment.
The camera position analysis pointer A is provided with a level 3 and an adjusting screw 4 as an adjuster.
The leveler 3 is for measuring the horizontal posture of the camera position analysis pointer A, and is attached to two bars 10a and 10b that extend horizontally and form a right angle.

  The adjustment screw 4 is for adjusting the camera position analysis pointer A to a horizontal posture, and is attached to the lower surface of the four spheres 2 arranged at the lower end so as to extend downward to form legs. The height is adjusted by changing the screwing depth accompanying the rotation of the adjusting screw 4.

In some cases, it may be necessary to install the camera position analysis pointer A in a horizontal posture during photo measurement. In this case, the horizontal position is confirmed by the leveling devices 3 and 3 and the horizontal position is set by the adjustment screw 4. be able to.
When the camera position analysis pointer A is set in a horizontal posture as described above, the coordinate system can be converted by designating the horizontal portion and the vertical portion after the camera position analysis.

  Next, FIG. 3 is a perspective view showing a camera position analysis pointer according to the third embodiment, and FIG. 4 is a perspective view showing a support for attaching the camera position analysis pointer to a tripod.

The camera position analysis pointer A is mounted on the tripod 5.
On a base 50 provided at the upper end of the tripod 5, a support base 6 formed in a cross shape with two plate members 60, 60 is attached, and the frame body 1 is placed inside grooves 61 formed at both ends of the plate member 60. The camera position analysis pointer A is attached to the support base 6 by fitting the rods 10a and 10b forming the.

It is a perspective view which shows the pointer for camera position analysis of 1st Example. It is a perspective view which shows the pointer for camera position analysis of 2nd Example. It is a perspective view which shows the pointer for camera position analysis of 3rd Example. It is a perspective view which shows the support stand for attaching the pointer for camera position analysis to a tripod.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Frame 10a Bar 10b Bar 10c Bar 2 Sphere 3 Level 4 Adjusting screw (adjuster)
5 Tripod 50 Base 6 Support base 60 Plate material 61 Groove A Camera position analysis pointer L1 Point-to-point distance L2 Point-to-point distance L3 Point-to-point distance

Claims (2)

  It is provided with a frame formed in a rectangular shape with a rod, and a sphere with the center as a point is attached to the corners of the eight places of this frame, the distance between the points of the spheres adjacent to the left and right, and the spheres adjacent to the front and back A pointer for camera position analysis used for photo measurement, characterized in that a distance between points and a distance between points of vertically adjacent spheres are set as reference scales. The camera position analysis pointer according to claim 1,
A camera position analysis pointer provided with a level device for measuring the horizontal posture of the camera position analysis pointer and an adjuster for adjusting the camera position analysis pointer to the horizontal posture.

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