WO2017026566A1

WO2017026566A1 - Three-dimensional scanning device and scanned three-dimensional image generating method for pipe

Info

Publication number: WO2017026566A1
Application number: PCT/KR2015/008971
Authority: WO
Inventors: 경동욱; 강병두
Original assignee: (주)씨소
Priority date: 2015-08-10
Filing date: 2015-08-27
Publication date: 2017-02-16

Abstract

The present invention relates to a three-dimensional scanning device and a scanned three-dimensional image generating for a pipe, capable of creating a shape model which conforms to a model according to a plurality of distance data sensed by a plurality of distance sensors having an overlapping sensing region, and generating a three-dimensional image for the inner surface of the pipe by mapping images picked up by a plurality of side cameras to the shape model, thereby improving scanning accuracy and reducing the manufacturing cost of the device.

Description

3D scanning device and 3D scan image generation method for pipe

The present invention relates to a technique for scanning an object, and more particularly, a three-dimensional scanning apparatus for a pipe that scans the inner surface of a pipe using a distance sensor and maps an image of a camera to a scan result to generate a three-dimensional image; It relates to a three-dimensional scan image generation method.

The three-dimensional scanner is a machine that can acquire and digitize the shape information of the object to be scanned. 3D scanners are used in the fields of automobile manufacturing, figure making, quality inspection, cultural property restoration, medical field, building field, and custom-made, and the range of their use is gradually increasing.

However, among the existing 3D scanners, high-precision scanners measure light by projecting light onto objects, which are used to scan small objects due to the influence of illumination and surface texture of the target to be scanned, and portable scanners have only one scanable area at a time. There is a narrow problem, and because broadband scanners are unable to check for obstructions such as occlusion during scanning, and once installed, they only scan once, so it takes a lot of time and expertise to calibrate to 3D images. There is a necessary problem.

On the other hand, pipe-like objects such as water pipes and wastewater pipes are difficult to scan inside by passing through the hollow inside by carrying a portable scanner, and the scan results are inaccurate. There is a problem that it is difficult to install the scanning equipment in the hollow inside.

Therefore, a new method for generating a three-dimensional image by efficiently scanning a medium-large object having an internal space in a longitudinal direction such as a pipe at a low cost is required.

An object of the present invention for solving the above problems is to generate a shape model of the pipe by scanning the inner surface of the pipe by using a plurality of distance sensors with a limited scan angle, and to map the captured image of the camera to the shape model 3 It is to provide a three-dimensional scanning device and a three-dimensional scan image generating method for a pipe for generating a dimensional image.

3D scanning device for a pipe of the present invention for achieving the above object, by scanning the inner surface of the pipe in the shape of a fan from the inside of the pipe to detect the distance to the inner surface of the pipe, the sensing area is constant with each other The plurality of distance sensors whose scan angles are set to partially overlap a common detection area, a plurality of side cameras photographing the inner surface of the pipe, and a model corresponding to the plurality of distance data detected by the plurality of distance sensors are common. And an image generation module for generating a shape model by matching the distance data of the sensing region of the sensor, and generating a 3D image of the inner surface of the pipe by mapping images taken by the plurality of side cameras to the shape model. It is characterized by.

In the three-dimensional scanning device for a pipe of the present invention, the plurality of distance sensors is a laser range finder.

In the 3D scanning apparatus for a pipe of the present invention, the image generation module generates a model corresponding to the plurality of distance data by using a scale-invariant feature transform (SIFT) algorithm and a random SAmple concensus (RANSAC) algorithm. It is characterized by.

In the three-dimensional scanning device for a pipe of the present invention, the image generation module, matching the central axis of the model corresponding to the plurality of distance data detected by the plurality of distance sensors, and the distance data of the common sensing area portion Computing an average value for, and matching the model corresponding to the plurality of distance data detected by the plurality of distance sensors according to the average value.

In the three-dimensional scanning device for a pipe of the present invention, the image generation module, characterized in that for correcting the alignment of the shape model along the central axis.

In the three-dimensional scanning device for a pipe of the present invention, the image generation module, by applying a white blending (alpha) blending (alpha) blending technique to the texture of the images taken by the plurality of side cameras It is characterized by mapping to the shape model.

In the three-dimensional scanning device for a pipe of the present invention, the image generating module is characterized in that the three-dimensional image is cut in the longitudinal direction of the pipe and unfolded to convert to a two-dimensional image.

In the three-dimensional scanning device for a pipe of the present invention, the front camera for photographing the front, characterized in that it further comprises a lighting module for illuminating the inner surface of the pipe.

In the method of generating a 3D scan image of a pipe of the present invention for achieving the above object, the 3D scanning apparatus is moved along the hollow inside the pipe, so that the sensing areas overlap with each other to form a common sensing area. Detecting a distance by scanning the inner surface of the pipe in the shape of a fan from the inside of the pipe using a plurality of distance sensors having a scanning angle set, and using the plurality of side cameras as the three-dimensional scanning device moves. Photographing, generating a shape model by matching a model corresponding to a plurality of distance data detected by the plurality of distance sensors using distance data of the common sensing area, and A 3D scanning device embeds images taken by the plurality of side cameras into the shape model. And it characterized by including the step of generating a three-dimensional image of the inner surface of the pipe.

In the method of generating a 3D scan image of a pipe of the present invention, the generating of the shape model corresponds to the plurality of distance data using a scale-invariant feature transform (SIFT) algorithm and a random SAmple concensus (RANSAC) algorithm. Characterized by generating a model.

In the method of generating a 3D scan image of a pipe of the present invention, the generating of the shape model includes: matching a central axis of a model corresponding to a plurality of distance data detected by the plurality of distance sensors, the common Computing an average value for the distance data of the sensing area, and matching the model corresponding to the plurality of distance data sensed by the plurality of distance sensors according to the average value.

In the method of generating a 3D scan image of a pipe of the present invention, the generating of the shape model may include correcting the shape model by aligning it along a central axis.

In the method of generating a 3D scan image of a pipe of the present invention, the generating of the 3D image may include white blending and alpha blending on textures of images captured by the plurality of side cameras. ) Is applied to the shape model.

In the method of generating a three-dimensional scan image for a pipe of the present invention, the three-dimensional scanning device further comprises the step of cutting the three-dimensional image in the longitudinal direction of the pipe and unfolding to convert to a two-dimensional image. do.

In order to achieve the above object, the present invention provides a computer-readable recording medium having recorded thereon a program for performing a three-dimensional scan image generation method for the pipe.

According to the three-dimensional scanning device and the three-dimensional scan image generation method for the pipe of the present invention, by matching the model to the plurality of distance data detected by the plurality of distance sensors to generate a shape model, by using a single distance sensor Scan accuracy can be improved compared to detection. In this case, by using a plurality of distance sensors having a limited scan angle but relatively low cost, the manufacturing cost of the device can be reduced.

In addition, it is possible to create a 3D image of a pipe by mapping the camera's image to a shape model, and cut the 3D image in the longitudinal direction and expand it into a planar shape to convert the image into a 2D image. You can check the status.

1 is a view showing a state of scanning a pipe according to an embodiment of the present invention.

2 is a block diagram showing the configuration of a three-dimensional scanning apparatus according to an embodiment of the present invention.

3 is a view showing a state of a three-dimensional scanning apparatus according to an embodiment of the present invention.

4 is a diagram illustrating a method of sensing a distance by scanning an inner surface of a pipe according to an embodiment of the present invention.

5 is a view showing a state of matching the model according to an embodiment of the present invention.

Figure 6 is a view showing the appearance of the shape model of the mesh form according to an embodiment of the present invention.

FIG. 7 illustrates a state in which the shape model of FIG. 6 is aligned along a central axis.

8 is a diagram illustrating a state in which a captured image is mapped to the shape model of FIG. 7.

FIG. 9 is a diagram illustrating a state in which the 3D image of FIG. 8 is converted into a 2D image.

10 is a diagram illustrating a process of generating a 3D scan image according to an embodiment of the present invention.

In the following description, only parts necessary for understanding the embodiments of the present invention will be described, it should be noted that the description of other parts will be omitted so as not to distract from the gist of the present invention.

The terms or words used in the specification and claims described below should not be construed as being limited to the common or dictionary meanings, and the inventors are appropriate to the concept of terms in order to explain their invention in the best way. It should be interpreted as meanings and concepts in accordance with the technical spirit of the present invention based on the principle that it can be defined. Therefore, the embodiments described in the present specification and the configuration shown in the drawings are only preferred embodiments of the present invention, and do not represent all of the technical idea of the present invention, and various equivalents may be substituted for them at the time of the present application. It should be understood that there may be variations and variations.

The present invention relates to a technology for generating a 3D image by scanning a scan object. Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a view showing a state of scanning a pipe according to an embodiment of the present invention, Figure 2 is a block diagram showing the configuration of a three-dimensional scanning apparatus according to an embodiment of the present invention, Figure 3 is a view of the present invention 4 is a view showing a state of a three-dimensional scanning apparatus according to an embodiment, Figure 4 is a view showing a state of detecting the distance by scanning the inner surface of the pipe in accordance with an embodiment of the present invention, Figure 5 is a view of the present invention According to an embodiment, a diagram illustrating a state of matching a model.

6 is a view showing a state of the shape model of the mesh form according to an embodiment of the present invention, FIG. 7 is a view showing the state of the shape model of FIG. 6 aligned along the central axis, FIG. 8 is FIG. FIG. 9 is a diagram illustrating a state in which photographed images are mapped to a shape model of FIG. 9, and FIG. 9 is a diagram illustrating a state in which the 3D image of FIG. 8 is converted into a 2D image.

1 to 9, the 3D scanning apparatus 10 moves along a hollow inside the pipe 30 and scans the inner surface of the pipe 30 with the assistance of the moving module 20. The movement module 20 is combined with the 3D scanning apparatus 10 to support the 3D scanning apparatus 10 to scan each part of the inner surface of the pipe as it moves. The pipe 30 may be a tubular structure, such as a water supply pipe or a waste water pipe, in which a space in which the 3D scanning apparatus 10 and the moving module 20 are movable is formed.

The 3D scanning apparatus 10 includes a plurality of distance sensors 11, a plurality of side cameras 12, an image generating module 13, a front camera 14, and an illumination module 15.

The plurality of distance sensors 11 scans the inner surface of the pipe 30 in a fan shape from the hollow center of the pipe 30 as the three-dimensional scanning device 10 moves through the hollow inside the pipe 30. It serves to detect the distance from the dimensional scanning device 10 to the inner surface of the pipe 30. 4 shows a state in which the three-dimensional scanning apparatus 10 scans the inner surface of the pipe as viewed in the cross-sectional direction of the pipe 30. Referring to FIG. 4, each of the sensors 11-1 and 11-2 included in the plurality of distance sensors 11 scans the inner surface of the pipe 30 in a predetermined direction according to a limited scan angle. The sensing area of the sensor 11-1 and the sensing area of the sensor 11-2 are set to overlap each other to form a

common sensing area

1 and 2. Accordingly, for each of the

common sensing regions

1 and 2, a plurality of distance data sensed by the sensor 11-1 and the sensor 11-2 may be generated.

Each of the sensors 11-1 and 11-2 included in the plurality of distance sensors 11 may be a laser range finder (LRF). The laser range finder may calculate a distance according to a time required by irradiating a laser to a target and detecting a reflected laser.

The plurality of side cameras 12 serves to photograph the inner surface of the pipe 30 as the 3D scanning apparatus 10 moves through the hollow inside the pipe 30. The plurality of side cameras 12 may photograph the inner surface of the pipe 30 by using a lens formed in the inner surface direction of the pipe 30 from the 3D scanning apparatus 10.

The image generation module 13 generates a 3D image of the pipe 30 by using the sensing results of the plurality of distance sensors 11 and the captured images of the plurality of side cameras 12. Since each sensor 11-1 and 11-2 included in the plurality of distance sensors 11 has a limited scan angle, the individual distance data sensed by each of the sensors 11-1 and 11-2 is separated from the pipe 30. The image generating module 13 matches the models corresponding to the plurality of distance data detected by the sensors 11-1 and 11-2, and then selects the 3D scanning apparatus 10. A shape model is created for the inner surface of the pipe 30 that encompasses an angle of 360 degrees around the center.

FIG. 5 shows a view of a shape model 19 generated in the cross-sectional direction of a pipe according to a sensing result of each of the sensors 11-1 and 11-2 included in the plurality of distance sensors 11. Referring to FIG. 5, the image generating module 13 generates a plurality of

models

3 and 4 corresponding to a plurality of distance data detected by the sensors 11-1 and 11-2, and models The central axis 5 of (3) and the central axis 6 of the model 4 are matched to form a common central axis 9. At this time, the image generation module 13 uses a scale-invariant feature transform (SIFT) algorithm for feature point extraction and a random SAmple concensus (RANSAC) algorithm that selects a model with the maximum consensus from the original data mixed with noise. ) Can be created. In addition, the image generation module 13 may determine the distance data of the model 3 and the model 4 with respect to each of the

portions

7 and 8 of the

models

3 and 4 corresponding to the

common sensing regions

1 and 2. The average value for the distance data is calculated, and the

models

3 and 4 are matched according to the calculated average value to generate the shape model 19.

Figure 6 shows the shape of the shape model generated in this way, has a mesh shape, the central axis is inclined and shifted. Accordingly, the image generation module 13 corrects the shape model as shown in FIG. 7 by correcting the shape model and aligning the shape model along the central axis.

As shown in FIG. 8, the image generating module 13 generates a 3D image of the inner surface of the pipe 30 by mapping textures of images captured by the plurality of side cameras 12 to a shape model. do. In this case, the image generation module 13 applies a white blancing technique to the images captured by the plurality of side cameras 12 to adjust the difference according to lighting, and alpha blending on the overlapping portions of the images. ) Can be mapped by applying the transmitted image.

When a three-dimensional image of the inner surface of the pipe 30 is generated through this process, the image generation module 13 may expand the three-dimensional image to a two-dimensional image as shown in FIG. 9 as necessary. have. In this case, the image generating module 13 may cut and spread the 3D image along the length direction of the pipe 30 to generate a planar 2D image, and the 2D image may be displayed by the user. Make it easier to identify.

In addition, the image generating module 30 may enlarge or reduce the three-dimensional image shown in FIG. 8 or the two-dimensional image shown in FIG. 9 or reduce or display the pipe diameter or the length of a specific portion as necessary. Can be provided.

The front camera 14 plays a role of photographing the front of the 3D scanning apparatus 10. The image photographed by the front camera 14 is referred to by the user for control when the position of the 3D scanning apparatus 10 is moved by using the moving module 20.

The lighting module 15 serves to illuminate the inner surface of the pipe 30 so that the plurality of side cameras 12 and the front camera 14 can take an image.

A process of generating a 3D image by scanning the pipe 30 according to the present invention will be described in detail with reference to FIG. 10.

Referring to FIG. 10, the 3D scanning apparatus moves to a hollow inside a pipe to be scanned with the aid of a moving module (S1).

The 3D scanning device located inside the pipe scans the inner surface of the pipe in a fan shape using a plurality of distance sensors, and detects the distance from the inside of the pipe to the inner surface (S2).

In this case, each of the plurality of distance sensors scans the inner surface of the pipe in a predetermined direction according to a limited scan angle, and a sensing area of a specific sensor and a sensing area of another sensor are partially overlapped with each other to form a common sensing area.

At this time, the plurality of distance sensors may be a laser range finder, and irradiates a laser to the inner surface of the pipe and measures the distance according to the time until the reflected laser is detected.

In addition, the 3D scanning device located inside the pipe photographs the inner surface of the pipe using a plurality of side cameras (S3).

In operation S4, the 3D scanning apparatus matches the central axes with respect to the plurality of models based on the data according to the distance detected in operation S2.

In operation S4, the 3D scanning apparatus may generate a model corresponding to the distance data using a SIFT algorithm for extracting feature points and a RANSAC algorithm for selecting a model.

Thereafter, the 3D scanning apparatus calculates an average value of the plurality of distance data of the common sensing region among the distance data sensed in step S2 (S5).

The 3D scanning apparatus generates a shape model for the pipe by matching a common sensing region according to the average value calculated in step S5 and matching a plurality of models according to the distance data sensed in step S2. (S6).

Thereafter, the 3D scanning apparatus aligns and corrects the shape model generated in step S6 along the central axis (S7).

Meanwhile, the photographing process in step S3 may be performed in parallel with step S2 or steps S4 to S7.

In operation S8, the 3D scanning apparatus generates a 3D image by mapping a texture of the image captured in operation S3 to a shape model corrected in operation S7.

In operation S8, the 3D scanning apparatus may map the shape model by applying a white balancing technique and an alpha blending technique to the texture of the image photographed in operation S3.

Thereafter, the 3D scanning apparatus converts the 3D image generated in step S8 into a 2D image according to a user's need (S9).

In operation S9, the 3D scanning apparatus may convert the 3D image generated in operation S8 into a planar 2D image by unfolding it in the longitudinal direction of the pipe.

The method for generating a 3D scan image according to an exemplary embodiment of the present invention may be implemented in a program form readable by various computer means and recorded on a computer readable recording medium.

On the other hand, the embodiments disclosed in the specification and drawings are merely presented specific examples to aid understanding, and are not intended to limit the scope of the present invention. It is apparent to those skilled in the art that other modifications based on the technical idea of the present invention can be carried out in addition to the embodiments disclosed herein. In addition, although specific terms are used in the specification and the drawings, they are only used in a general sense to easily explain the technical contents of the present invention and to help the understanding of the present invention, and are not intended to limit the scope of the present invention.

Claims

A plurality of distance sensors configured to scan the inner surface of the pipe from the inside of the pipe in a fan shape to detect a distance to the inner surface of the pipe, wherein a scan angle is set to overlap a predetermined portion with each other to form a common sensing area;

A plurality of side cameras photographing the inner surface of the pipe; And

A model corresponding to a plurality of distance data detected by the plurality of distance sensors is matched using distance data of the common sensing area to generate a shape model, and the images captured by the plurality of side cameras are mapped to the shape model. An image generation module for generating a 3D image of the inner surface of the pipe;

3D scanning apparatus for the pipe, characterized in that it comprises a.
The method of claim 1,

And said plurality of distance sensors is a laser range finder.
The method of claim 1,

The image generation module may generate a model corresponding to the plurality of distance data by using a scale-invariant feature transform (SIFT) algorithm and a random SAmple concensus (RANSAC) algorithm.
The method of claim 1,

The image generating module matches a central axis of a model corresponding to the plurality of distance data detected by the plurality of distance sensors, calculates an average value of the distance data of the common sensing area, and calculates the plurality of values according to the average value. And a model corresponding to the plurality of distance data detected by the distance sensor of the pipe.
The method of claim 1,

The image generation module,

3D scanning apparatus for a pipe, characterized in that for correcting by aligning the shape model along a central axis.
The method of claim 1,

The image generation module may be configured to apply a white blancing technique and an alpha blending technique to the textures of the images photographed by the plurality of side cameras to map the shape model. 3D scanning device.
The method of claim 1,

The image generating module is a three-dimensional scanning device for a pipe, characterized in that for cutting the three-dimensional image in the longitudinal direction of the pipe and unfolding to convert to a two-dimensional image.
The method of claim 1,

A front camera for photographing the front;

An illumination module for illuminating the inner surface of the pipe;

Three-dimensional scanning device for the pipe, characterized in that it further comprises.
The three-dimensional scanning device moves along the hollow inside the pipe, and the inner surface of the pipe is fan-shaped from the inside of the pipe by using a plurality of distance sensors whose scan angles are set so that the detection areas overlap each other to form a common detection area. Detecting the distance by scanning;

Photographing the inner surface of the pipe by using the plurality of side cameras as the 3D scanning apparatus moves;

Generating, by the 3D scanning apparatus, a shape model by matching a model corresponding to a plurality of distance data detected by the plurality of distance sensors using distance data of the common sensing area; And

Generating a 3D image of the inner surface of the pipe by mapping the images photographed by the plurality of side cameras to the shape model by the 3D scanning apparatus;

3D scan image generation method for a pipe comprising a.
The method of claim 9,

The generating of the shape model may include generating a model corresponding to the plurality of distance data using a scale-invariant feature transform (SIFT) algorithm and a random SAmple concensus (RANSAC) algorithm. How to create an image.
The method of claim 9,

Generating the shape model,

Matching a central axis of a model corresponding to a plurality of distance data sensed by the plurality of distance sensors;

Calculating an average value of distance data of the common sensing area;

Matching a model corresponding to a plurality of distance data detected by the plurality of distance sensors according to the average value;

3D scan image generation method for a pipe comprising a.
The method of claim 9,

The generating of the shape model may include correcting the shape model by aligning the shape model along a central axis.
The method of claim 9,

The generating of the 3D image may include mapping to the shape model by applying a white blending technique and an alpha blending technique to the textures of the images photographed by the plurality of side cameras. 3D scan image generation method for pipe.
The method of claim 9,

The 3D scanning apparatus cutting the 3D image in the longitudinal direction of the pipe and expanding the 3D image to a 2D image;

3D scanning image generation method for the pipe, characterized in that it further comprises.
A computer-readable recording medium having recorded thereon a program for performing the method for generating a three-dimensional scan image of a pipe according to claim 9.