JP2018084509A - Image measurement method, image measurement device and image measurement program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To more accurately measure an actual distance between two points.SOLUTION: An image measurement method for measuring an actual distance between two specific points reflected in an image includes the steps of: installing a rod having colored parts of at least two places; photographing the rod so as to settle the entire rod within an image; acquiring colored position information showing respective distances between respective end points of the colored parts and an end point of the rod; extracting pixels approximate to color components colored on the colored parts from image data, measuring the linearity of a cluster generated by performing labeling processing on the basis of spatial connections of the pixels, and detecting a part measured as the linearity as a colored part; acquiring information showing two places being measurement objects of distance, designated by a user; and measuring the distance from the positions of the end points of the colored parts and the colored position information on the basis of a principle of projective transformation and a least square method.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an image surveying method, an image surveying apparatus, and an image surveying program.

  In laying overhead lines, which are one of communication infrastructure facilities, there is a case where the minimum ground clearance of the laid overhead lines is defined. Therefore, in order to prove that the ground clearance of the installed overhead line complies with the regulations, the overhead height of the overhead line is measured using a long bar-shaped measuring ruler (hereinafter referred to as a measuring bar) after the construction of the overhead line. At the same time, the overhead line to be measured and the measuring rod are photographed by the camera so as to fit into one photograph. The measuring rod is, for example, a measuring rod PL0 as shown in FIG. 8, and is an extendable / contractible rod on which a scale MJ is written as shown. At the time of measurement, the measuring rod is set up perpendicular to the ground at the measurement target point. And a measurement is performed by a field worker reading the value which the scale MJ in the state which the measurement rod PL0 extended from the ground to the position of an overhead line shows. Then, the measurement data of the measured overhead line of the overhead line and the on-site photograph taken together with the overhead line and the measuring rod PL0 are used as a trail.

However, since measurement with a conventional measuring rod is performed by a field worker visually confirming the scale written on the measuring rod, the measurement data stored in the database is not always accurate. There is. In general, the measurement data is once written down by a field worker and then reflected in the database afterwards, so there is a problem in terms of work efficiency in storing measurement data.
Moreover, it is difficult to accurately grasp the overhead height of overhead lines in field photographs taken with both overhead lines and measuring rods, and it is often insufficient as a trail. This is because even if a measuring rod is installed at the measurement target point and photographed with a camera along with the overhead line, if the measurement target overhead line is captured in a photograph, the scale size indicated on the measuring rod is relative to the image. This is because it is difficult to confirm the scale value written on the measuring bar from the image.

  Therefore, for example, without performing visual measurement using a measuring rod, the ground height is determined from only the captured image by a measurement method based on triangulation using a binocular stereo camera (for example, Non-Patent Document 1). A method of measuring can be considered. Further, for example, a method of measuring the distance from the camera to the measurement object by photographing a calibration board used in 3D (Three-Dimensional) measurement together with the measurement object is conceivable.

Xugang, Saburo Tsubasa, “3D Vision”, Kyoritsu Publishing Co., Ltd., 1998, pp 95-97

However, introducing a new device such as a twin-lens stereo camera at the site of laying work just for the purpose of measuring the overhead height of the overhead line is a problem of the introduction cost of the device and a change in the work process of the field worker. In general, it may be difficult because of the problem. For example, in measurement using a calibration board, handling of the calibration board is a complicated work process for general field workers. Furthermore, in the measurement, since it is necessary to prepare in advance information such as values of parameters (for example, focal length, etc.) for shooting with the camera, especially when a plurality of cameras of different models are used. Management of advance information becomes complicated.
Due to the above-mentioned problems, in the management of laying work of overhead wires, it is necessary to introduce new equipment on the site and to prevent changes in the work process of site workers as much as possible. There is a need for a mechanism that can accurately measure the height of the height and accumulate on-site photographs that can be used sufficiently as trails.

  The present invention has been made in view of such circumstances, and more accurately measures the actual distance between two points from an image taken on site without introducing a new device or work process at the site. The purpose is to provide technology.

  One aspect of the present invention is an image surveying method for measuring an actual distance between two specific places in an image taken by a camera, and measures a bar having at least two colored portions. A measuring rod installation step to be installed at a point to be imaged, an image shooting step of taking an image with the camera so that the whole of the installed rod fits in the image, and image storage for saving image data indicated by the taken image A coloring position information input step for acquiring coloring position information indicating respective distances between the end points of the coloring portions at two locations and the end points of the bars, and the image stored in the image storing step. An image input step for acquiring image data, and extracting pixels that approximate the color component colored in the chromatic part from the image data, and based on the spatial connection of the pixels A coloring portion detection step of performing a labeling process, measuring a linearity of a cluster generated by the labeling process, and detecting a portion that is measured to be more straight in the image based on the image data as a coloring portion; A measurement position designation step for obtaining information indicating two locations that are the measurement targets of the distance in the image, designated based on an operation input, the position of the end point of the chromatic portion in the image, and the chromatic position information Based on the principle of projective transformation and the least square method, a distance measurement step for measuring the distance between the two locations to be measured, and a result of outputting the measurement result of the distance by the distance measurement step And an output step.

  One aspect of the present invention is the image surveying method described above, wherein in the coloring portion detection step, the inertia principal axis of the cluster is calculated, and an index based on a ratio between the dispersion in the principal axis direction and the dispersion in the direction perpendicular to the principal axis is used. The linearity is measured.

  One aspect of the present invention is the image surveying method described above, wherein, in the coloring portion detection step, a peripheral portion of the specific portion in the image designated based on an operation input by a user is defined as the end point of the coloring portion. The search target area in the search is used.

  One aspect of the present invention is an image surveying device for measuring an actual distance between two specific places in an image taken by a camera, and is installed in a point to be measured. An image input unit for acquiring image data indicated by the image photographed by the camera so that the entire bar having the colored portion is within the image, and each end point of the colored portion and the rod A chromatic position information input unit for acquiring chromatic position information indicating the distance between each end point of the image, and a pixel that approximates a color component colored in the chromatic part from the image data, The labeling process is performed based on the connection, the straightness of the cluster generated by the labeling process is measured, and the portion measured to be more straight in the image based on the image data is measured. A chromatic part detection unit that detects a color part, a measurement position designation part that is designated based on an operation input by a user, and that acquires information indicating two locations that are measurement targets of the distance in the image; From the position of the end point of the chromatic part and the chromatic position information, based on the principle of projective transformation and the method of least squares, a distance measuring unit that measures the distance between the two locations to be measured; and And a result output unit that outputs a measurement result of the distance by the distance measurement unit.

  One aspect of the present invention is an image survey program for causing a computer to execute the image survey method described above.

  According to the present invention, it is possible to more accurately measure the actual distance between two points from an image taken on site without introducing a new device or work process at the site.

It is a figure which shows an example of the measurement stick | rod used in the surveying by the image surveying system which concerns on embodiment of this invention. It is a block diagram which shows the function structure of the image surveying system which concerns on embodiment of this invention. It is a block diagram which shows the function structure of the coloring part detection part of the image surveying system which concerns on embodiment of this invention. It is a flowchart which shows the operation | movement in the image imaging process by the image surveying system which concerns on embodiment of this invention. It is a flowchart which shows the operation | movement in the distance measurement process by the image surveying system of embodiment which concerns on this invention. It is the schematic which shows the outline | summary of limitation of the search range of the coloring partial end point by the image surveying apparatus which concerns on embodiment of this invention. It is the schematic which shows the specific outline | summary of the measurement position end point by the image surveying apparatus which concerns on embodiment of this invention. It is a figure which shows an example of the conventional measuring rod.

[Embodiment]
Hereinafter, embodiments of the present invention will be described.
The image surveying apparatus according to the present embodiment includes two measurement objects at a measurement target point (for example, a specific part of a laid overhead line and two places on the ground) together with a measurement bar that is colored. The actual distance between the two locations to be measured (for example, the ground height of the installed overhead line) is measured from the image data indicating the image taken by the imaging device (hereinafter also referred to as a camera). Can do. In addition, since the image surveying apparatus according to the present embodiment stores the image data, the actual distance between the two locations to be measured can be measured at any time by analyzing the image data afterwards. Can do.

Hereinafter, the case where the ground height of the laid overhead wire is measured will be described as an example.
The measuring rod used in the present embodiment is colored so that it can be visually recognized on a specific portion of the measuring rod even when the measuring rod is taken by a camera from a distance. And this measuring rod is installed in the measurement object point, and is image | photographed with a camera with the overhead line which is a measurement object. The image surveying device can measure the ground height of the overhead line by analyzing image data indicating the photographed image.

  Note that the measuring bar is colored with a predetermined color at two or more positions with a predetermined interval. FIG. 1 is a diagram illustrating an example of a measuring rod used in measurement by an image surveying system according to an embodiment of the present invention. As shown in the drawing, in the coloring portion CL1 between the location “a” and the location “b” and the coloring portion CL2 between the location “c” and the location “d” of the measuring rod PL1. Each is colored. Here, it is assumed that all are colored in red so that they can be easily seen even when taken from a distance. Thus, the measuring rod used in the measurement by the image surveying system according to the embodiment of the present invention has at least two colored portions like the measuring rod PL1 shown in FIG.

  Further, image data indicating an image photographed by the camera is transferred to an image surveying device (hereinafter also referred to as a personal computer) constituted by, for example, a working personal computer (personal computer). The image surveying apparatus performs image processing on the transferred image to thereby each end point of the coloring portion CL1 and the coloring portion CL2 of the measuring rod PL1 (that is, “a”, “b”, “c” shown in FIG. 1). And the position of “d”) are recognized (detected). Alternatively, the image surveying apparatus recognizes the positions of the end points of the chromatic part CL1 and the chromatic part CL2 of the measuring bar PL1 by correcting the position specified by the operation input from the user with a mouse or the like.

The image surveying apparatus is based on the straight line obtained by extending the measuring rod PL1 on the image based on the positions and intervals of the end points of the coloring portion CL1 and the coloring portion CL2 of the measuring rod PL1 recognized above. The actual distance between any two locations can be measured.
Therefore, according to the image surveying apparatus according to the present embodiment, for example, if an on-site photograph taken together with the overhead line and the measuring rod Pl1 is stored, the actual overhead line height from the on-site photograph can be obtained whenever necessary. Therefore, the reliability of the on-site photograph as a trail of construction can be improved.

  In addition, according to the image surveying apparatus according to the present embodiment, the work process of a conventional field worker that photographs both the overhead line and the measuring rod PL0 with a camera is changed, or a new apparatus is introduced to the field. This eliminates the need for a field worker to visually read the value of the scale MJ written on the measuring rod PL0, and thus it is possible to easily leave a highly reliable work trail.

(Functional configuration of image survey system)
Hereinafter, the functional configuration of the image surveying system will be described.
FIG. 2 is a block diagram showing a functional configuration of the image surveying system 1 according to the embodiment of the present invention. As shown in the figure, the image surveying system 1 includes an imaging device 10 and an image surveying device 20.

  As illustrated, the imaging apparatus 10 includes a control unit 100, an image capturing unit 101, an image storage unit 102, and an output unit 103.

  The control unit 100 controls each functional block of the imaging device 10. The control unit 100 includes, for example, a CPU (Central Processing Unit).

  The image capturing unit 101 captures the entire measurement rod PL1 having at least two colored portions installed at the measurement target point and the two measurement target points at the measurement target point within the image. To do. The image capturing unit 101 includes, for example, a camera.

  The image storage unit 102 stores the image data indicated by the image captured by the image capturing unit 101. The image storage unit 102 is a storage medium such as an HDD (Hard Disk Drive), flash memory, EEPROM (Electrically Erasable Programmable Read Only Memory), and RAM (Random Access read / write Memory). Memory), ROM (Read Only Memory), or any combination of these storage media.

  The output unit 103 is an output interface for outputting the image data stored in the image storage unit 102 to the image surveying device 20. The data transmission means from the imaging apparatus 10 to the image surveying apparatus 20 may be any means, for example, data transmission by wireless LAN communication or data transfer via a storage medium such as a memory card. Good.

  As illustrated, the image surveying device 20 includes a control unit 200, a storage unit 201, a color position information input unit 202, an image input unit 203, a color portion detection unit 204, a measurement position designation unit 205, and a distance. A measurement unit 206 and a result output unit 207 are included.

  The control unit 200 controls each functional block of the image surveying device 20. The control unit 200 includes a CPU, for example.

  The storage unit 201 stores various data and programs used by the image surveying device 20. For example, the storage unit 201 stores image data output from the imaging device 10. The storage unit 201 is configured by a storage medium, for example, an HDD, a flash memory, an EEPROM, a RAM, a ROM, or any combination of these storage media.

  The chromatic position information input unit 202 is input in advance by an administrator of the image surveying apparatus 20 or the like, and the end points (for example, the drawing portion CL1 and the chromatic portion CL2) of the two chromatic portions (the chromatic portion CL1 and the chromatic portion CL2) of the measuring bar PL1. Color position information indicating the respective distances between the positions of “a”, “b”, “c”, and “d” shown in FIG. 1 and the end points of the measuring rod PL1 is acquired. The acquired color position information is stored in the storage unit 201.

  The image input unit 203 is an input interface to which image data output from the output unit 103 of the imaging apparatus 10 is input. As described above, the data transmission means from the imaging apparatus 10 to the image surveying apparatus 20 may be any means, for example, data transmission by wireless LAN communication, or data via a storage medium such as a memory card. It may be a transfer.

The chromatic part detection unit 204 extracts pixels that approximate the color components colored in the chromatic part CL1 and the chromatic part CL2 from the image data, performs a labeling process based on the spatial connection of the pixels, and performs the labeling process. By measuring the linearity of the generated cluster, a portion that is measured to be more straight in the image based on the image data is detected as a coloring portion.
Further, the chromatic part detection unit 204 calculates the inertial principal axis of the cluster, and measures the linearity by an index based on the ratio between the dispersion in the principal axis direction and the dispersion in the direction perpendicular to the principal axis.
Further, the chromatic part detection unit 204 sets a peripheral part of the specific part in the image designated based on the operation input by the user as a search target area in the search for the positions of the end points of the chromatic part CL1 and the chromatic part CL2.
Note that the detection processing of the positions of the end points of the chromatic part CL1 and the chromatic part CL2 by the chromatic part detection unit 204 will be described in detail in the description of the operation of the image survey system 1 described later.

  The measurement position specifying unit 205 acquires information indicating two locations that are distance measurement targets specified in the image based on an operation input by the user.

  The distance measuring unit 206 calculates the distance between the two locations to be measured based on the principle of projective transformation and the least square method from the positions of the end points of the chromatic portions CL1 and CL2 and the chromatic position information in the image. measure.

  The result output unit 207 outputs the distance measurement result measured by the distance measurement unit 206. For example, information indicating the distance between two locations to be measured is displayed on a display (not shown) provided in the result output unit 207 or the like.

(Functional configuration of the color part detection unit)
Hereinafter, the functional configuration of the chromatic part detection unit 204 will be described in more detail.
FIG. 3 is a block diagram showing a functional configuration of the chromatic part detection unit 204 of the image surveying device 20 according to the embodiment of the present invention. As illustrated, the chromatic part detection unit 204 includes a binary image conversion unit 2041, a labeling processing unit 2042, an inertia main axis calculation unit 2043, a linear shape detection unit 2044, and an end point position designation input unit 2045. Consists of.

  The binary image conversion unit 2041 sets the pixel of the color that is colored in the chromatic part CL1 and the chromatic part CL2 of the measuring bar PL1 in the image data read from the working memory to 1, and sets the other pixels to 0. Thus, it is converted into binary image data.

  The labeling processing unit 2042 performs a labeling process on the binary image based on the binary image data converted by the binary image conversion unit 2041. As a result, different IDs are assigned to the respective chromatic portions (the chromatic portion CL1 and the chromatic portion CL2).

  The inertia main axis calculation unit 2043 obtains an inertia main axis for each of the chromatic portions (the chromatic portion CL1 and the chromatic portion CL2) to which the ID is assigned.

  The linear shape detection unit 2044 detects a portion that is a “straight-like shape lump” on the image based on a predetermined detection rule. For example, if the value of “(dispersion in the main axis direction) ÷ (dispersion in the direction perpendicular to the main axis)” is larger than a predetermined threshold value, the straight line shape detection unit 2044 detects “a lump that looks like a straight line”. .

  The end point position designation input unit 2045 accepts an operation input by the user for designating a specific position on the image. For example, the end point position designation input unit 2045 receives an operation input by the user for designating the position of the end point of the chromatic portion (the chromatic portion CL1 and the chromatic portion CL2) and the position of the end point of the measuring bar PL1.

(Operation of image survey system)
Hereinafter, the operation of the image surveying system 1 will be described.
FIG. 4 is a flowchart showing the operation in the image photographing process by the image surveying system according to the embodiment of the present invention. FIG. 5 is a flowchart showing the operation in the distance measurement process by the image surveying system according to the embodiment of the present invention.
First, each step in the image photographing process shown in FIG. 4 will be described. This flowchart is started when shooting by the imaging apparatus 10 is performed.

(Step S101) A measuring rod PL1 (see FIG. 1) preliminarily colored is installed perpendicularly to the ground by a site worker or the like at a measurement target point on the site. Note that the measuring rod PL1 is a rod that can be expanded and contracted, and a hook FK for hooking on an overhead wire is provided at one end. Accordingly, when the field worker or the like extends the measuring rod PL1 toward the ground from the state where the hook FK is hooked on the overhead wire, the field worker or the like becomes independent in a state where the measuring rod PL1 is perpendicular to the ground. Can be installed. Thus, by installing the measuring rod PL1 perpendicular to the ground, the length of the measuring rod PL1 becomes the same as the height of the overhead wire above the ground.
In addition, although the scale for a measurement (for example, scale MJ shown in FIG. 8) is described in the general measurement rod, it is not particularly necessary in the present invention.

  Further, it is assumed that the colored portions are provided in at least two places of the measuring rod PL1, and are colored. In addition, in order to simplify description, in the following description, it is assumed that there are two colored portions (the colored portion CL1 and the colored portion CL2 shown in FIG. 1) as in the measurement rod PL1 shown in FIG. To do. Further, it is assumed that the positions of “a”, “b”, “c”, and “d” of the measuring rod PL1 shown in FIG. 1 are known. Further, the distance between the position “a” and the position “b”, the distance between the position “b” and the position “c”, and the position “c” and the position “d”. It is assumed that the distance between them is predetermined. For example, the distance between the position “a” and the position “b”, the distance between the position “b” and the position “c”, and the position “c” and the position “d”. The distance between them is defined as “30 cm”, “40 cm”, and “30 cm”, respectively.

The measuring rod PL1 has a structure in which, for example, cylindrical parts having different thicknesses are nested like a general tripod foot, and is extended by sliding each part. For this reason, since the inner part may be covered by the outer part, the outermost part (that is, the thickest part) is colored. The color of the chromatic color is arbitrary, but a primary color that is easily detected by the chromatic color portion detection unit 204 described later is desirable. In the present embodiment, it is assumed that the colored portion is colored in red.
Thereafter, the process proceeds to step S102.

(Step S102) The image capturing unit 101 of the imaging apparatus 10 captures the measurement rod PL1 installed in Step S101 together with the overhead line to be measured. At this time, the imaging rod 10 is photographed so that the entire measuring rod PL1 fits into one image, and the thickness of the measuring rod PL1 is at least one pixel or more in the photographed image. Shooting is performed after adjusting the distance to the subject. Note that the number of times of photographing may be one, but in order to improve the accuracy of measurement, photographing may be performed a plurality of times.
Thereafter, the process proceeds to step S103.

(Step S103) The image storage unit 102 of the imaging device 10 stores image data indicating the image captured by the image capturing unit 101 in step S102. Further, the output unit 103 of the imaging device 10 outputs the image data to the image surveying device 20. The image input unit 203 of the image surveying device 20 acquires the image data output from the imaging device 10. Then, the storage unit 201 of the image surveying device 20 stores the image data acquired by the image input unit 203. In the present embodiment, the image data is stored in the image storage unit 102 of the imaging device 10 and the storage unit 201 of the image surveying device 20, but the present invention is not limited to this. The image data may be stored in only one of the image storage unit 102 of the imaging device 10 and the storage unit 201 of the image surveying device 20.
Above, the process of this flowchart is complete | finished.

  Next, each step in the distance measurement process shown in FIG. 5 will be described. This flowchart starts when information indicating the position of the end point of the chromatic portion (the chromatic portion CL1 and the chromatic portion CL2) of the measuring rod PL1 is input to the image surveying device 20.

(Step S201) From the grounding portion of the end point on the side that contacts the ground of the measuring rod PL1 (the end point on the side not equipped with the hook FK) as the coloring position information, “a”, “b”, “c”, and Information indicating the length up to “d” (see FIG. 1) is input from the coloring position information input unit 202 of the image surveying device 20 and stored in the storage unit 201 in advance.
Thereafter, the process proceeds to step S202.

(Step S202) The image input unit 203 reads the image data stored in the storage unit 201 in step S103 of the image photographing process described above, and stores it in the work memory. The working memory may be included in the storage unit 201, or may be a storage medium (not shown) different from the storage unit 201.
Thereafter, the process proceeds to step S203.

(Step S203) The binary image conversion unit 2041 of the chromatic part detection unit 204 converts the image data read from the work memory into red (colors colored in the chromatic part CL1 and the chromatic part CL2 of the measuring bar PL1 described above). ) Is set to 1 and other pixels are set to 0, thereby converting to binary image data.
For example, the binary image conversion unit 2041 has both “R ÷ G” and “R ÷ B” values calculated from the RGB (Red, Green, Blue) values of each pixel included in the image data. When it is larger than a predetermined threshold, it is determined that the pixel is red. The binary image conversion unit 2041 converts the image data into binary image data by performing the same determination on all the pixels.

Next, the labeling processing unit 2042 of the chromatic part detection unit 204 performs a labeling process on the binary image based on the binary image data. Thereby, a different ID is assigned to each block of red pixels.
Next, the inertia main axis calculation unit 2043 of the chromatic part detection unit 204 obtains an inertia main axis for each red pixel block to which the ID is assigned.
Then, if the value of “(dispersion in the main axis direction) ÷ (dispersion in the direction perpendicular to the main axis)” is greater than a predetermined threshold value, the linear shape detection unit 2044 of the chromatic part detection unit 204 determines that “a shape that seems to be a straight line”. Detected as a lump. Note that the method for determining the linearity is not limited to the above method, and the linearity may be defined by other methods.

The chromatic part detection unit 204 recognizes the cluster of red pixels detected by the above processing as the chromatic part of the measuring bar PL1.
Note that the above-described index for determining “redness” and “straightness” may be another index different from the above index. For example, the straight line shape detection unit 2044 sorts “lumps that are likely to be straight lines” based on the index of “straightness of the straight line”, and (when there are two coloring portions), the top two red A configuration in which a block of pixels is recognized as a chromatic portion (colored portion CL1 and chromatic portion CL2) of the measuring rod PL1 may be employed.

  In order to make the detection accuracy of the chromatic portions (the chromatic portion CL1 and the chromatic portion CL2) of the measuring rod PL1 more accurate, a user (for example, an administrator of the image surveying device 20) inputs an end point position designation of the chromatic portion detection unit 204. The position of each end point of the colored portion CL1 and the colored portion CL2 of the measuring rod PL1 may be sequentially specified by manual operation (for example, clicking the mouse while viewing the image) from the unit 2045. In this case, the linear shape detection unit 2044 limits the detection range of the chromatic portion CL1 and the chromatic portion CL2 based on the position of the end point designated by the user, and performs the above-described detection of the chromatic portion only in the limited detection range. do it.

As a method for limiting the detection range, for example, as shown in FIG. 6, from the line segment ad connecting the two farthest end points among the end points designated by the user, the color portion CL1 and the color portion CL2 A rectangular range ar1 can be defined as a detection range. FIG. 6 is a schematic diagram showing an outline of limitation of the search range of the colored partial end points by the image surveying device according to the embodiment of the present invention.
As described above, when the user specifies the candidate positions of the end points of the chromatic part CL1 and the chromatic part CL2, the exact end point position may not be specified due to a blurring in the click operation of the mouse. However, according to the above-described method, the position of the end point can be corrected to a more accurate position in step S204 described later. It should be noted that in a scene where the accuracy of measurement is not so important, the linear shape detection unit 2044 may recognize the range connecting the end points specified by the user as the colored portion of the measuring rod as it is. .
Thereafter, the process proceeds to step S204.

(Step S204) The measurement position specifying unit 205 of the image surveying device 20 is a measurement bar specified by a manual operation (for example, clicking a mouse while viewing an image) by a user (for example, an administrator of the image surveying device 20). Information indicating the positions of both ends of PL1 is acquired.
The distance that can be measured by the image surveying device 20 according to the present embodiment is a distance between any two points located on a straight line obtained by extending the measurement rod PL1 in the image. In the present embodiment, the distance between both ends of the measuring rod PL1 (that is, the length of the measuring rod PL1) is measured. Even in the manual operation described above, the exact end point position may not be specified due to, for example, a shake in the mouse click operation. However, the end point position should be corrected to a more accurate position by the following method. Is possible.

As shown in FIG. 7, the measurement position specifying unit 205 specifies an end point to be measured from the chromatic part detected in the chromatic part detection step S203. FIG. 7 is a schematic view showing a specific outline of the measurement position end point by the image surveying apparatus according to the embodiment of the present invention.
The measurement position designating unit 205 calculates, for example, an inertia main axis that combines all areas detected as the chromatic part (two areas in FIG. 7), and projects all pixels of the chromatic part along the main axis. Then, the position of the end point is specified on the principal axis from the projected component (that is, the positions of “a ′”, “b ′”, “c ′”, and “d ′” shown in FIG. 7). Similarly, for the positions designated by the user (ie, “e” and “f” shown in FIG. 7), the measurement position designation unit 205 projects the new position (ie, shown in FIG. 7) onto the main axis. “E ′” and “f ′”).

In S203, when a manual operation is performed by the user, one end may be designated. In that case, it is sufficient to specify the other end.
Thereafter, the process proceeds to step S205.

(Step S205) The distance measuring unit 206 of the image surveying apparatus 20 measures the distance between “e ′” and “f ′” specified in Step S204. The distance measuring unit 206 is based on the principle of projective transformation, and the distance on the image between the end points “a ′”, “b ′”, “c ′”, and “d ′” of the chromatic part, and the known actual It is calculated by calculating backward from the distance.

  Specifically, the distance on the image between the position “a ′” and the position “f ′” is the image between the position “k”, the position “b ′”, and the position “−f ′”. The upper distance is "l", the distance on the image between the position of "c '" and the position of "f'" is the distance between "m", the position of "d '" and the position of "f'" The distance on the image is “n”, and the distance on the image between the position “e ′” and the position “f ′” is “x”, and the position “a ′” and the position “f ′” The actual distance between the position is “K”, the actual distance between the position “b ′” and the position “f ′” is “L”, the position “c ′” and the position “f ′”. If the actual distance between the positions is “M” and the actual distance between the position “d ′” and the position “f ′” is “N”, (k, K), (l, L) , (M, M), (n, N), and the 2 × 2 projective transformation shown in the following formula (1) by the least square method. It is possible to calculate the column.

  If the matrix A shown in Expression (1) is used, the actual distance “X” between the position of “e ′” and the position of “f ′” can be obtained from Expression (2) below.

Here, the values “K”, “L”, “M”, and “N” correspond to the color position information stored in the work memory in step S202. Further, as described above, since the projective transformation matrix A shown in the equation (1) is calculated by the least square method, even if the number of end points is larger, the calculation is performed without substantially changing the equation. It is possible. Therefore, in the present embodiment, the number of the colored portions of the measuring rod PL1 is two, but even if there are three or more, the measurement can be performed by the same arithmetic processing. .
Thereafter, the process proceeds to step S206.

(Step S206) The result output unit 207 of the image surveying apparatus 20 outputs the measurement result obtained in step S205. At that time, the result output unit 207 detects the respective detection positions of the coloring portion CL1 and the coloring portion CL2 of the measuring bar PL1 detected on the screen in step S203, and on the screen designated by the user in step S204. The positions of the two points may be output at the same time by being superimposed on the input screen.
Above, the process of this flowchart is complete | finished.

  As described above, the image surveying system 1 according to the present invention can easily measure the distance between two points (for example, the overhead height of the overhead wire) from one measuring rod with a specific coloring and one image obtained by photographing it. Distance) can be measured. Further, the image surveying system 1 according to the present invention saves image data indicating a photographed image, and thereafter, means for proving that the overhead height of the overhead wire is higher than a prescribed height. Can be provided.

  You may make it implement | achieve at least one part of the image surveying apparatus 20 or the image surveying system 1 in embodiment mentioned above with a computer. In that case, a program for realizing this function may be recorded on a computer-readable recording medium, and the program recorded on this recording medium may be read into a computer system and executed. Here, the “computer system” includes an OS and hardware such as peripheral devices. The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Furthermore, the “computer-readable recording medium” dynamically holds a program for a short time like a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line. In this case, a volatile memory inside a computer system serving as a server or a client in that case may be included and a program held for a certain period of time. Further, the program may be a program for realizing a part of the above-described functions, and may be a program capable of realizing the functions described above in combination with a program already recorded in a computer system. You may implement | achieve using programmable logic devices, such as FPGA (Field Programmable Gate Array).

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes designs and the like that do not depart from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Image surveying system, 10 ... Imaging device, 20 ... Image surveying device, 100 ... Control part, 101 ... Image photographing part, 102 ... Image storage part, 103 ... Output unit 200 ... Control unit 201 ... Storage unit 202 ... Colored position information input unit 203 ... Image input unit 204 ... Colored portion detection unit 205 ... Measurement position Designation unit, 206 ... Distance measurement unit, 207 ... Result output unit, 2041 ... Binary image conversion unit, 2042 ... Labeling processing unit, 2043 ... Inertial spindle calculation unit, 2044 ... Linear shape detection unit, 2045 ... Endpoint position designation input unit

Claims (5)

An image surveying method for measuring the actual distance between two specific places in an image taken by a camera,
A measuring rod installation step for installing a rod having at least two colored portions at a point to be measured;
An image shooting step of shooting with the camera so that the entire installed bar fits within the image;
An image storage step for storing image data indicated by the captured image;
A coloring position information input step of obtaining coloring position information indicating each distance between each end point of the two colored portions and the end point of the bar;
An image input step of acquiring the image data stored in the image storage step;
A pixel that approximates the color component colored in the chromatic part is extracted from the image data, a labeling process is performed based on the spatial connection of the pixels, and a linearity of a cluster generated by the labeling process is measured. A color portion detection step for detecting a portion measured as being more straight in the image based on the image data as a color portion;
A measurement position designation step for obtaining information indicating two locations that are the measurement targets of the distance in the image, designated based on an operation input by a user;
A distance measuring step of measuring the distance between the two locations to be measured based on the principle of projective transformation and the least square method from the position of the end point of the chromatic part in the image and the chromatic position information. When,
A result output step of outputting the measurement result of the distance by the distance measurement step;
An image surveying method.   2. The image surveying method according to claim 1, wherein in the coloring portion detection step, an inertial principal axis of a cluster is calculated, and the linearity is measured by an index based on a ratio between a dispersion in a principal axis direction and a dispersion in a direction perpendicular to the principal axis. .   The said coloring part detection step WHEREIN: The surrounding part of the specific part in the said image designated based on the operation input by a user is made into the search object area | region in the search of the said end point of the said coloring part. Image surveying method. An image surveying device for measuring an actual distance between two specific places in an image taken by a camera,
An image input unit that acquires image data indicated by the image taken by the camera so that the whole of the bars having at least two colored portions that are installed at a point to be measured fit within the image;
A coloring position information input unit for acquiring coloring position information indicating each distance between each end point of the two colored portions and the end point of the bar;
A pixel that approximates the color component colored in the chromatic part is extracted from the image data, a labeling process is performed based on the spatial connection of the pixels, and a linearity of a cluster generated by the labeling process is measured. A color portion detection unit that detects a portion that is more likely to be a straight line in the image based on the image data as a color portion;
A measurement position designation unit that is designated based on an operation input by a user, and that acquires information indicating two locations that are measurement targets of the distance in the image;
A distance measuring unit that measures the distance between the two locations to be measured from the position of the end point of the chromatic part in the image and the chromatic position information based on the principle of projective transformation and the least square method When,
A result output unit for outputting the measurement result of the distance by the distance measurement unit;
An image surveying apparatus comprising:   An image surveying program for causing a computer to execute the image surveying method according to any one of claims 1 to 3.

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