JP4169282B2 - Photogrammetry system and photogrammetry method - Google Patents

Description

  The present invention relates to a photogrammetry system and a photogrammetry method.

   Conventionally, photogrammetry using digital photographic images has been carried out for monitoring behavior of slopes for disaster prevention and measuring air displacement in tunnels.

In photogrammetry, a required number of targets (measurement points) are set on a survey object such as a slope, and the target is manually photographed from at least two arbitrary points with a digital camera, etc. To acquire the image of the above, and to analyze the image based on the photogrammetry theory (Patent Documents 1 to 3), repeatedly obtaining the three-dimensional coordinates of the survey object, and grasp the behavior (change over time) It is.
This is only necessary if two or more images with different parallax can be acquired by shooting from an arbitrary position, so that direct access to the hazardous area is reduced, and on-site survey and survey time can be shortened. There is.
JP 2004-325073 A Japanese Patent Laid-Open No. 7-27563 JP 2002-181536 A

  However, in conventional photogrammetry, the operator manually operates the digital camera etc. every time shooting is performed, so repeated shooting can be performed from the same location each time or continuously in real time. was difficult.

  In the above image analysis work, it is necessary to input the camera position / posture and the position coordinates of the measurement point on the image. Conventionally, however, the camera position / posture is often different each time a picture is taken. Even if the images are acquired, the position of the target on each acquired image is greatly different, and in the analysis work, matching of each image must be performed manually. It was difficult to observe changes over time in surveyed objects.

  Therefore, an object of the present invention is to provide a photogrammetry system and a photogrammetry method that can easily observe the temporal change of a survey object.

The present invention according to claim 1 is provided on the surface of the surveying object together with a plurality of targets a... Installed on the surface of the surveying object, and the absolute position of each target a. A plurality of position sensors b... Measuring the distance between the targets a... And a distance sensor c... Measuring the distance between the targets a. A plurality of fixed point cameras d1, d2,... For photographing photographic images, a plurality of object photograph images photographed by the fixed point cameras d1, d2,... And a target a measured by the position sensor b. ... And a distance between the plurality of targets a... Measured by the distance sensor c... f) It is a photogrammetry system consisting of.

The present invention described in claim 2 is the photogrammetry system according to claim 1, wherein the distance sensor c is an optical fiber sensor in which an optical fiber is laid on the surface of the survey object.

According to the third aspect of the present invention, the terminal e (f) is an absolute image of an object photograph image taken at different times and a target a ... measured by the position sensor b ... at the time of photographing each image. 3. The photogrammetry system according to claim 1, wherein the three-dimensional displacement of the survey object is obtained from the position and the distance between the targets a... Measured by the distance sensor c.

The present invention according to claim 4 is the distance between a plurality of targets a..., A plurality of position sensors b... Measuring the absolute position of the target a. , And a plurality of fixed point cameras d1, d2,... For shooting the object photographic images containing the targets a are installed and fixed at different positions. A plurality of object photograph images photographed by the fixed point cameras d1, d2,..., The absolute position of the target a... Measured by the position sensor b..., And the target a measured by the distance sensor c. ... Is a photogrammetry method for calculating the three-dimensional coordinates of the survey object according to the distance between them.

The present invention according to claim 5 is a photograph of an object photograph taken at different times, the absolute position of the target a... Measured by the position sensor b. 5. The photogrammetry method according to claim 4, wherein the three-dimensional displacement of the survey object is obtained from the distance between the targets a.

According to the present invention, it is possible to more easily observe the temporal change of a surveying object by using the object photograph image taken by the fixed point camera, the absolute position of the target, and the distance between the targets.

A plurality of targets a ... installed on the surface of the survey object, and a plurality of position sensors b installed on the surface of the survey object together with the target a ... for measuring the absolute position of each target a ... ... and a distance sensor c ... for measuring the distance between the targets a ... and a plurality of fixed-point cameras for photographing object photographic images installed and fixed at different positions and containing the targets a ... .., a plurality of object photograph images taken by the fixed point cameras d1, d2,..., the absolute position of the target a... measured by the position sensor b. A photogrammetry system comprising a terminal e (f) for extracting each target a ... and calculating its three-dimensional coordinates based on the distance between the plurality of targets a ... measured by the sensor c ... .

A plurality of targets a..., A plurality of position sensors b... Measuring the absolute position of the target a... And a distance sensor c. , And a plurality of fixed-point cameras d1, d2,... For shooting the object photographic images containing the targets a... Are fixed at different positions, and the fixed-point cameras d1, d2,. The above surveying is based on a plurality of photographed object photograph images, the absolute position of the target a ... measured by the position sensor b ..., and the distance between the targets a ... measured by the distance sensor c ... A photogrammetry method for calculating the three-dimensional coordinates of an object.

  Hereinafter, embodiments in which the present invention is applied to slope behavior monitoring will be described in detail.

  As shown in FIG. 1, the photogrammetry system of the present invention includes a plurality of targets a... Which are installed on the surface of a slope which is a survey object at an appropriate interval, and the above slope along with the targets a. GPS receivers (position sensors) b... And optical fiber sensors (distance sensors) c.

  The system further includes two fixed-point cameras d1 and d2 that can be photographed including all the targets a... Installed on the slope and are fixed at different positions, and fixed-point cameras d1 and d2. Which has a terminal (field terminal) e such as a personal computer that analyzes the image taken and outputs the analysis result, and another terminal (remote terminal) f... Connected to the field terminal e. is there.

The target a is a plate-like object in which the central portion surrounded by the white outer peripheral frame portion is painted black and the contrast between the outer peripheral frame portion and the central portion is increased.
This target a... Is fixed at an appropriate position on the slope so as to move integrally with the slope when the slope behaves.
The fixing is performed by, for example, drilling a fixing hole in the target a... And attaching it to a single clamp, and fixing this to an anchor made by drilling a hole in concrete on a slope. Moreover, it is good also as fixing with a double-sided tape.

  The target a can be recognized as long as it can be recognized by image processing and its position can be easily specified, and its shape and color can be changed as appropriate. In order to be able to cope with measurement at night or in bad weather, it is preferable to use a light source such as an LED as a target.

  The GPS receiver b... Is installed at the same position together with at least one of the targets a..., And measures and outputs the absolute position of the target a. However, in this system, even if this is omitted, observation using relative coordinates can be performed.

  The optical fiber sensor c... Is formed by laying an optical fiber between a plurality of arbitrarily selected targets a... On the slope surface, and the precision of the distance between the targets a. Measurement and ground strain (displacement) measurement.

The fixed-point cameras d1 and d2 are digital still cameras that are installed and fixed at different positions so that all or a part of the target a. Digital images (referred to as “object photographic images”) having the above-mentioned targets a.
The fixed point cameras d1 and d2 are housed in a waterproof case so as to withstand wind and rain, and are fixed so that their installation positions and postures do not move.
The fixing method can be performed, for example, by driving a single tube into the ground and fixing the camera to the single tube with a single clamp.

The fixed point cameras d1 and d2 may be provided with a CCD sensor, a CMOS sensor, or the like as an image sensor.
If an infrared camera is used, it is easy to measure at night and in bad weather.

  Furthermore, the present invention is not limited to a still camera, and may be a digital video camera or a TV camera that continuously shoots an object photographic image as a moving image.

The fixed-point cameras d1 and d2 have an interface such as USB or IEEE and are connected to the field terminal e via a wired or wireless network, and are connected to the field terminal e in real time or at regular intervals (for example, every several milliseconds). (It may be every few minutes, every few hours, or every few days).
Three or more cameras may be installed.

The field terminal e is installed in a field office, for example, and includes image display / storage means, image analysis means, analysis result output means, GPS information acquisition means, length information acquisition means, etc. The GPS receiver b... and the optical fiber sensor c... are connected by wired or wireless communication paths such as USB, IEEE, LAN, and the Internet.
In the case of wired communication, the cable for the communication path is selected according to the distance, but if the distance exceeds several hundred meters, it is preferable to use an optical fiber.

The image display / storage means of the field terminal e displays the object photographic image sent from the fixed point cameras d1 and d2 in real time on the display or the like, and the object photographic image sent thereto. At regular intervals.
The storage can also be performed when a change in the image is detected by the motion detection process or when a storage operation is performed artificially.

The image analysis means of the site terminal e analyzes the object photographic images acquired at the same time by the fixed point cameras d1 and d2, and recognizes the target a in each image. Then, each target a... Included in both images is associated (matched), and the three-dimensional coordinates (relative coordinates) of each target a.
The same processing is repeated for a series of object photograph images stored at each time, the three-dimensional coordinates of each target a at each time are obtained, and each target (slope) is compared in chronological order. Is calculated.

  In the conventional photogrammetry system, target matching between a plurality of photos is performed manually. However, since the photogrammetry system of the present invention fixes the fixed point cameras d1 and d2 at predetermined positions, The matching operation can be easily performed by using the data of the three-dimensional coordinates of the past image that has already been analyzed as it is or by using a process for correcting the error. Therefore, it is easy to automate the work that has been performed manually.

  The GPS information acquisition means of the field terminal e acquires the absolute coordinates of the GPS receiver b at the time of acquiring the object photograph image from the GPS receiver b.

  The length information etc. acquiring means of the field terminal e is the laying section (between the arbitrarily selected targets a and a at the time when the object photograph image is acquired from the optical fiber sensor c. ), And information on the position and magnitude of ground distortion in the meantime.

  The analysis result output means of the field terminal e is specified by the three-dimensional coordinates of the plurality of targets a... Based on the data from the image analysis means, the GPS information acquisition means, the length information etc. acquisition means. The results of analysis of the running, inclination, displacement, etc. of the surface to be output are displayed in a list or plotted by a plotting program.

The remote terminal f... Is installed at a remote location such as a head office, for example, and is connected to the site terminal e via the Internet or the like, and transmits / receives various information to / from the site terminal e. The same control, analysis, display, etc. as the terminal e can be performed.
All processing of the on-site terminal e may be performed by the remote terminal f.

  The photogrammetry method of the present invention uses the photogrammetry system of the present invention configured as described above, and performs a series of processes as shown in the flowchart of FIG.

  First, the required number of targets a ... and GPS receivers b ... are installed on the slope, and the optical fiber sensor c ... is installed, and the fixed-point cameras d1, d2 are installed at different positions. (Step S1).

  Then, the fixed point cameras d1 and d2 capture the object photographic images containing the targets a and send the data to the site terminal e. This photographing and transmission are always performed at a required time interval, and the image display / storage means of the field terminal e displays the object photograph images sent from the fixed point cameras d1 and d2 in real time on the display ( Step S2). Therefore, the state of the slope can be constantly monitored on the display.

The above-mentioned image display / storage means of the field terminal e stores in the storage device an object photograph image that is photographed at the same time by the two fixed point cameras d1 and d2 and is displayed every moment on the display at regular intervals. Save (step S3).
At this time, the coordinate data output from the GPS receiver b... Is stored, and further the data such as the distance of the laying position and the ground displacement from the optical fiber sensor c.
Note that the above-described object photograph image and data may be stored when a change is detected by comparing the object photograph images before and after being arranged in chronological order, not at regular intervals.

The image analysis means analyzes the two object photograph images acquired and stored by the image display / storage means, and extracts and recognizes the target a ... in each object photograph image (step S4). .
Then, the targets a... In the object photograph images are matched, and the three-dimensional coordinates (relative coordinates) of the targets a.

The same analysis is sequentially repeated for a series of object photograph images photographed and stored at different times, and the three-dimensional coordinates of the target a at each time are calculated.
Since the positional relationship between the fixed point cameras d1 and d2 and the target a..., The orientation of the fixed point cameras d1 and d2, the focal length, and the like are the same as in the previous shooting, the recognition of the target a. The matching of the targets a... Between the images can be easily performed by using the already calculated three-dimensional coordinate data of the targets a.

Then, based on the three-dimensional coordinates of each target a... At each time, that is, by comparing the three-dimensional coordinates of each target a. Displacement) is obtained and used as an observation result (step S5).
The output of the observation result is obtained by observing the absolute coordinate system based on the target a by specifying the absolute position of any of the targets a based on the absolute position information from the GPS receiver b. It is also possible to output as a result.
In addition, the accuracy can be improved by using the information on the distance between the specific targets a and a from the optical fiber sensor c... And the position and size of the distortion occurring between them.

  The observation results obtained as described above are displayed on the display or the like as a list output or illustrated as analysis results of the travel, inclination, displacement, etc. of the surface specified by the target (step S6). By looking at the analysis results in chronological order, it is possible to easily grasp the temporal change of the slope.

  In this photogrammetry system, the slope is constantly monitored by fixed point cameras d1 and d2, and the measurement of the three-dimensional coordinates and the observation of the three-dimensional displacement are automated to save labor. That is, since the fixed-point cameras d1 and d2 are fixed at fixed positions, the deviation of the target a. Therefore, in the image analysis, the operations that have been performed manually in the past, such as automatic recognition of the target a... In the object photograph image and matching of the target a.

  As described above, since image analysis is easy, observation of three-dimensional displacement can be performed continuously in real time and automatically, and not only can labor saving be realized, but also a GPS receiver b. When measurement is also performed with other automatic measuring devices such as the fiber sensor c..., It is easy to improve measurement accuracy by linking with these.

In addition, the measurement accuracy can be improved by statistical processing or the like in the coordinate calculation of the target a.
Furthermore, the acquired image can be used as a database by storing and managing it.

  In the above description, it is assumed that the three-dimensional displacement of the survey object is observed by two or more cameras. However, in the case of two-dimensional measurement, one camera is sufficient.

The photogrammetry system of the present invention can be applied not only to slope monitoring, but also to behavior monitoring of various grounds such as natural ground and artificial ground, and behavior monitoring of various structures such as buildings and tunnels. it can.
For example, it can be used for construction management such as monitoring of landslides, monitoring of collapsed slopes including cases of earthquakes, excavation work, and the like.
In addition to monitoring for disaster prevention, it is also possible to measure how many centimeters the door is opened, how many centimeters the person entering and leaving is monitoring while monitoring the opening and closing of the building door.

It is a system block diagram of the Example which used this invention photogrammetry system for slope monitoring. It is the flowchart which showed the flow of the process of the system.

Explanation of symbols

a Target (measurement point)
b GPS receiver (position sensor)
c Optical fiber sensor (distance sensor)
d1, d2 fixed point camera e, f terminal

Claims (5)

A plurality of targets installed on the surface of the survey object;
A plurality of position sensors that are installed on the surface of the survey object together with the target and measure the absolute position of each target;
A distance sensor for measuring the distance between the targets;
A plurality of fixed-point cameras that are fixedly installed at different positions and shoot an object photo image containing the plurality of targets;
The three-dimensional coordinates of the survey object based on the plurality of object photograph images taken by the fixed point camera, the absolute position of the target measured by the position sensor, and the distance between the targets measured by the distance sensor A photogrammetry system comprising a terminal for calculating 2. The photogrammetry system according to claim 1, wherein the distance sensor is an optical fiber sensor in which an optical fiber is laid on the surface of the survey object. The terminal is a survey object based on the object photograph images taken at different times, the absolute position of the target measured by the position sensor at the time of photographing each image, and the distance between the targets measured by the distance sensor. 3. The photogrammetric system according to claim 1, wherein a three-dimensional displacement of the object is obtained. On the surface of the survey object, a plurality of targets, a plurality of position sensors for measuring the absolute position of each target, and a distance sensor for measuring the distance between the targets are installed, and the object containing the target Multiple fixed-point cameras that take photographic images are installed and fixed at different positions.
The three-dimensional coordinates of the survey object based on a plurality of object photograph images taken by the fixed point cameras, the absolute position of the target measured by the position sensor, and the distance between the targets measured by the distance sensor A photogrammetry method characterized by calculating The three-dimensional of the survey object is obtained from the object photograph image photographed at different times, the absolute position of the target measured by the position sensor at the time of photographing each image, and the distance between the targets measured by the distance sensor. 5. The photogrammetry method according to claim 4, wherein the displacement is obtained.

Images