WO2006129977A1

WO2006129977A1 - Method and device for simultaneously outputting images of internal front and lateral sides of a pipe

Info

Publication number: WO2006129977A1
Application number: PCT/KR2006/002110
Authority: WO
Inventors: Won Dae Kim; Hye Kyung Kim
Original assignee: Cleanpipe Eng. & Const. Co., Ltd.
Priority date: 2005-06-02
Filing date: 2006-06-01
Publication date: 2006-12-07
Also published as: KR100657226B1; KR20060125143A

Abstract

According to a method and a device for simultaneously outputting images of front and side views of an inside of a tubular way of the present invention, a camera stacked to an investigation system moving in a tubular way forward along an inner wall thereof, is attached with a lens adapter in the center of a front part thereof for photographing images of forward views and inner wall views of the tubular way and transmitting the photographed images to the camera, wherein the inner wall images in the range of 360° perpendicular to a peripheral surface of the lens adapter are incident to a side surface of the lens adapter and reflected therefrom to be transmitted to the camera, and the images received by the camera are respectively distinguished into the forward image data and the inner wall image data by a data processing unit and simultaneously displayed or drawn in the form of a single image.

Description

METHOD AND DEVICE FOR SIMULTANEOUSLY

OUTPUTTING IMAGES OF INTERNAL FRONT AND

LATERAL SIDES OF A PIPE

Technical Field

[1] The present invention relates to a method of simultaneously outputting images of front and lateral views in a tubular way such as a drain pipe, and a device used for the method in a self-propelled investigation system including a photographing camera, a lens adapter for 360° image photographing, and a supporting unit. More particularly, the present invention relates to a method for simultaneously outputting images of front and side views in a tubular way, and a device therefor, in which planar images are obtained as data for a range of 360° by a lens adapter and all the images are displayed or drawn in a single image in a developed state via image processing of a computer for representing information on an inside of a tubular way clearly. Background Art

[2] Conventionally, it has been widely known that an investigation system checks an internal state of a tubular way while moving in the tubular way. The investigation system is disposed in the tubular way in which various liquid, gas, slurry and the like flows, and photographs inside views of the tubular way by using a camera and an illumination unit stacked thereto while moving in the tubular way. The photographed images are transmitted to a computer via wire or wirelessly, and the computer processes the images to determine defects of the tubular way. The camera used in the conventional investigation system scans forward views only in the tubular way to obtain image data for an inner surface of a tubular way. In the particular cases, the camera rotates in every direction toward the inner wall surface of the tubular way to photograph detailed images gradually or partially. Also, the camera obtains images by a camera angle of 180° or higher. The obtained images are collected, so that overlapped portions thereof are deleted and the remaining thereof is reconstructed via complicated procedure. Further, the images obtained as above include distorted portions more than data obtained in an orthogonal direction via orthogonal projection, so that precise analysis thereof becomes difficult and the value of the data becomes decreased.

[3] Fig. 11 is a schematic view of a conventional investigation system as described above. In Fig. 11, the investigation system photographs images for forward views in a tubular way F by a camera C mounted in a front part of a self-propelled vehicle A, while the self-propelled vehicle A moves. Such the image photographing method currently used as above has a disadvantage that it is impossible to precisely recognize damaged portions or surface changes in the tubular way since the self-propelled vehicle moves forward while scanning the forward views. Further, the camera has a focusing position not in the center but at a lower part eccentrically, so that the value of the obtained images becomes non-uniform at an upper part and a lower part of the image. Therefore, precise diagnosis on the situations in the tubular way F becomes difficult.

[4] Fig. 12 is a schematic view of another prior art investigation system. In Fig. 12, the investigation system includes a self-propelled vehicle A disposed in the center of a tubular way F, a camera C stacked in a front part of the self-propelled vehicle A, and a convex fisheye lens L coupled with a front part of the camera. According to this conventional investigation system, images are obtained in a 180° range via the fisheye lens L and the obtained images are developed. The conventional investigation system has, however, a disadvantage that images of unnecessary areas are included in the images obtained by the fisheye lens L since the fisheye lens L is simply attached to the camera C and obtains images of a large range. Further, the images obtained by the fisheye lens L have serious distortion, so that image processing has to be carried out for narrow areas of pixel units when processing image units obtained by the fisheye lens L. As described hereinabove, the conventional investigation systems have disadvantages that the photographed images for the inner surfaces of the tubular way are distorted and exhibit a noticeably low resolution since the investigation systems scan only the forward views or photograph wall surfaces of the tubular way by simple combination with the fisheye lens. Disclosure of Invention Technical Problem

[5] The present invention has been developed to solve the above disadvantages of the prior arts.

[6] An object of the present invention is an object to provide a method and a device for simultaneously outputting images of front and side views in a tubular way, in which images for front and side views of an inside of a tubular way may be combined simultaneously into a single image by using a lens adapter mounted in a front part of a camera of an investigation system. The image obtained is used for the movement of the investigation system by recognizing forward situations in the tubular way. Further, the side views are divisionally photographed with minimum distortion but with high resolution and the divisionally photographed images are compiled together and displayed into the single image, thereby realizing effective management based on the compiled information on the inner wall of the tubular way. Furthermore, the front and side views simultaneously photographed as above may be displayed divisionally for effective management thereof, and the situations of the tubular way may be displayed or drawn in a developed image via post-processing or realtime processing.

[7] Another object of the present invention is to provide a device for simultaneously outputting images for front and side views in a tubular way, in which a self-propelled type investigation system includes a camera and a lens adapter attached to the camera for photographing images in the range of 360 and a supporting unit in a simple structure is further provided so that inner wall portions of the tubular way at a same distance in an orthogonal direction may be photographed by the lens adapter while the investigation system is moving. Technical Solution

[8] In order to achieve the above objects of the present invention, according to an aspect of the present invention, there is provided a method for outputting images of front and side views of an inside of a tubular way simultaneously, which includes the steps of inputting images of a front part of the tubular way via a front center portion of a lens adapter mounted in a front part of a camera stacked on an investigation system which moves in the tubular way forward or along an inner wall thereof, and transmitting the input images to the camera, transmitting images of the inner wall of the tubular way in the range of 360° to the camera, wherein the inner wall is perpendicular to a peripheral surface of the lens adapter, and wherein the images are incident to a side surface of the lens adapter and reflected therefrom to the camera, dividing the images transmitted from the camera into image data for front views and inner wall views via an image data processing unit of a computer and simultaneously obtaining a single image to be displayed or drawn for the divisional images, displaying the data on a screen via the image data processing unit of the computer, and outputting images for defects or damaged portions via the displayed image by determining movement situations of the investigation system.

[9] In order to achieve the above objects of the present invention, according to another aspect of the present invention, there is provided a device for outputting images of front and side views of an inside of a tubular way simultaneously, which includes a su pporting unit coupled with a periphery of an investigation system stacking a camera and having wheels contacting an inner wall of the tubular way variably for positioning the camera in the center of the tubular way, a lens adapter coupled in a front part of the camera for simultaneously obtaining images of front views and images in a direction perpendicular to the inner wall of the tubular way by transmitting the images to the camera, and a data processing unit for displaying or drawing the images simultaneously received from the camera into a single image capable of representing front view images and inner wall view images divisionally.

Advantageous Effects

[10] The present invention as described hereinabove has an advantage that the image data recording the forward views and the image data for the inner wall of the tubular way obtained via reflection in the orthogonal direction observation are obtained divisionally and transmitted divisionally, so that the both image data for the forward view and the inner wall may be obtained simultaneously and output via a single image by single photographing work.

[11] Further, differently from the conventional fisheye lens or the forward scanning type camera, the photographing position may be kept in the center always by using the supporting unit in the simple structure, so that the information on not only the forward part but also the inner wall of the tubular way may be obtained with relatively little distortion but with high resolution. Therefore, observation information or visual information may be provided in detail for obtaining a developed image for the inner wall.

[12] Furthermore, image processing becomes simple since images obtained by the image output device always represent the states of the inner wall of the tubular way on predetermined parts thereof uniformly by the camera and the image data processing unit. Also, the preparation of the developed image may be achieved by simply cutting the image data in the shape of ring and developing the cut image data. Therefore, the developed image for the inner wall of the tubular way may be obtained with high precision simply.

[13] Differently from the prior art, in which images are photographed for all area via a camera angle of 180 by dividing resolution for required portions, according to the present invention, images for parts orthogonal to the camera and required portions among the all area are simply obtained without deterioration of the resolution, and the required portions of the tubular way may be expanded and observed partially. Brief Description of the Drawings

[14] Fig. 1 is a perspective view of an investigation system for simultaneously outputting images of front part and side views in a tubular way according to a preferred embodiment of the present invention;

[15] Fig. 2 is a cross-sectional view for showing an operation principle of a lens adapter according to a preferred embodiment of the present invention;

[16] Fig. 3 is a schematic view for showing an image range of a subject photographed by the lens adapter of Fig. 2;

[17] Fig. 4 and Fig. 5 are cross-sectional views respectively showing changes of the image range of a subject photographed by a curved surface or a plane surface of a reflection lens of the lens adapter according to the preferred embodiment of the present invention;

[18] Fig. 6 is a diagram for showing analysis on errors and distortions of image output information on the subject according to the present invention;

[19] Fig. 7 is a cut and developed view for showing processing particulars of the image output information on the subject according to the present invention;

[20] Fig. 8 is a perspective view showing an image investigation system for simultaneously outputting images of front part and side views in a tubular way according to another preferred embodiment of the present invention;

[21] Fig. 9 and Fig. 10 are front views for showing photographing or recovering states of the investigation system of Fig. 8, which is positioned in a tubular way;

[22] Fig. 11 is a schematic view of a prior art image obtaining device via front scanning; and

[23] Fig. 12 is a schematic view of a prior art image obtaining device using a fisheye lens. Best Mode for Carrying Out the Invention

[24] Now the preferred embodiments according to the present invention will be described with reference to the accompanying drawings.

[25] Fig. 1 is a perspective view of a device for simultaneously outputting an image for front and side views in a tubular way according to a preferred embodiment of the present invention, Fig. 2 is a cross-sectional view for showing an operation principle of a lens adapter according to a preferred embodiment of the present invention, and Fig. 9 and Fig. 10 are front views for showing photographing or recovering states of an investigation system, which is positioned in a tubular way.

[26] As shown in Fig. 1 and Fig. 9, a device for simultaneously outputting an image for front and side views in a tubular way, includes an investigation system 1, a camera 2 mounted to a front part or a rear part of the investigation system 1 , a lens adapter 3 coupled with a front part of the camera, a supporting unit 4 mounted to a periphery of the investigation system 1 for moving the investigation system 1 and having a driving unit 41, and a self-propelled vehicle 5 for moving the investigation system 1 into a tubular way 6. The camera 3 includes a unit for transmitting photographed image data, and the investigation system 1 incorporates a power controller (not shown) including batteries inside for operating relating parts. The camera 2 of the investigation system 1, the driving unit 41 of the supporting unit 4 and the vehicle 5 are connected to each other wirelessly or via cables.

[27] The lens adapter 3 includes, as shown in Fig. 2, a transparent cylindrical case 31 coupled with the front part of the camera 2 at an end and extended by a predetermined length, a curved lens 32 disposed around a lens of the camera 2 at a rear end in the case 31, a reflection element 33 disposed at a front end in the case 31 and formed in a curved or plane surface shape corresponding to the curved lens 32, and a center lens 34 disposed in the center of the reflection element 33 for scanning a forward view.

[28] The case 31 is fixed to the camera 2 by screw-coupling after controlling a focus of an image, and then connected to the camera 2 via a usual connection socket or mutual fitting. The case 31 is formed of a glass of high transparency for transmitting an image of an inner wall of the tubular way 6 to the curved lens 32 disposed in the case 31 , wherein a synthetic resin tube may be used as the case 13 because of its simple machining and handling characteristics.

[29] The curved lens 32 is formed of a curved surface for reflecting and collecting incident images of the inner wall of the tubular way in an orthogonal direction, wherein the images are transmitted via an optical center axis of the lens of the camera 2. A size of the image input to the camera 2 is changed by the increase or decrease of a curvature angle of the curved lens 32.

[30] The reflection element 33 serves to reflect the images of the inner wall of the tubular way 6, which is transmitted from the curved lens 32, for transmitting the images along the optical center axis of the lens of the camera 2. The reflection element 33 is formed with a plane or curved surface, as shown in Fig. 4, and Fig. 5. The camera 2 outputs image data D of the inner wall in the shape of big and small doughnuts. The size of the output image data D for the inner wall is selected optimally according to identification, situation recognition and image processing or correction in the use thereof.

[31] The center lens 34 is disposed in the center of the reflection element 33 and transmits the images of the forward view in the tubular way 6 via the optical center axis of the camera lens. The images transmitted to the camera 2 and output according to the change in the size and curvature angle of the center lens 34 are displayed as forward image data D' in the shape of big and small circles by the center lens 34, as shown in Fig. 4 and Fig. 5.

[32] The lens adapter 3 constructed as above, scans forward views in the tubular way 6 via the center lens 34 and scans the inner wall of the tubular way 6 via the curved lens 32 and the reflection element 33 in the orthogonal direction. The forward images of the tubular way 6 transmitted via the center lens 34 and the images transmitted via the curved lens 32 and the reflection element 33 have projection centers laid on the same line with the center of the lens of the camera 2. The images incident via the lens adapter 3 is transmitted to an image data processing unit 7 of a computer via the camera 2, and distinguished via a screen 8. The forward image data D' and the inner wall image data D are coupled with each other, wherein the forward images are positioned in the center and the inner wall images are positioned in the periphery in the shape of ring respectively or to be combined with each other.

[33] Among the images obtained as above, the circle-shaped forward image data D' positioned in the center is used for operating the vehicle 5 via a control unit connected thereto via wire or wirelessly, as shown in Fig. 9. In the case of using the forward image data D¹ on the spot, the forward image data D¹ is expanded and observed for carrying out the observation function, which has been realized by a conventional forward scanning type camera.

[34] Further, among the images obtained as above, the image data D of the inner wall of the tubular way 6 is photographed in the shape of a strap forming a circle as shown in Fig. 6, and the image data is transformed to be developed by the image data processing unit 7 incorporating application programs for image transformation correction and image processing, so that a developed image for the inner wall of the tubular way 6 is obtained as a drawing. The preparation of the developed image drawing is achieved by cutting the image data D for the inner wall from the image, in which the image data D and the forward image data D' are combined together, and dividing the cut image data D at predetermined portions, so that the divided ones are developed in the shape of a straight strap. As shown in Fig. 6, image distortion generated at outer parts is corrected by quadratic equation conversion, polynomial image conversion, or inverse orthogonal projection and the like, and then spread out in the shape of the straight strap, so that current states of the inner wall of the tubular way 6 may be judged precisely. The inverse orthogonal projection is the inverse of orthogonal projection in which same portions are transformed with a same area.

[35] As described above, according to the image output device provided with the lens adapter 3 of the present invention, images for the entire inner wall of the tubular way 6 may be obtained per predetermined section by a predetermined time interval or a predetermined distance interval as the investigation system 1 stacking the camera 2 moves by an advancing speed of the vehicle 5. The images obtained by the image unit or the time interval unit are processed and corrected to unit images and the unit images are connected to each other to establish a single developed image for the entire inner wall of the tubular way 6. The single image may be partially taken to be expanded for observation as necessary.

[36] When obtaining image data for the inside of the tubular way 6 by the image output device of the present invention, the lens adapter is always located in the center of the tubular way 6 for minimizing errors and distortion. Therefore, the supporting unit 4 is provided to the image output device of the present invention.

[37] The supporting unit 4 includes, as shown in Fig. 1 and Fig. 8, unit supporting dies

43 disposed at two positions with a predetermined distance from each other and re- spectively having an end hinge-coupled with a peripheral surface of the investigation system 1 and the other end coupled with a group of three wheels 42, a disc plate 44 or a connection die 45 for making the wheels 42 of the unit supporting dies 43 contact the inner wall surface of the tubular way 6 to position the camera 2 and the lens adapter 3 to the center of the tubular way 6 or separate the camera 2 and the lens adapter 3 from the inner wall surface for recovery or simple movement, and a driving element 41 coupled with the disc plate 44 or the connection die 45 for driving the same.

[38] The driving element 41is formed of any one selected from a hydraulic cylinder, an air cylinder or a reduction motor respectively supplied with a fluid, air or power from the outside.

[39] In the operation of the supporting unit 4 as shown in Fig. 9, six supporting dies 43 spread outward and 6 wheels 42 contact the inner wall of the tubular way 6 as the disc plate 44 or the connection die 45 moves by the operation of the driving element 41. The contact state between the wheels 42 and the inner wall of the tubular way 6 represents that the lens adapter 3 is positioned in the center of the tubular way 6 always, wherein a best image for the inner wall of the tubular way 6 may obtained in this state. In this state, the investigation system 1 photographs the inner wall while moving in the tubular way 6 forward or backward by the vehicle 5, and desired images may be obtained with minimum errors and minimum distortion.

[40] The image photographing work for the inner wall or the forward view is finished in the contact state between the wheels 42 of the supporting unit 4 and the inner wall of the tubular way 6. At this time, the driving element 41 is driven inversely to inversely move the disc 44 or the connection die 45, which pushes the supporting dies 43 outward. Then, the supporting dies 43 becomes collected as shown in Fig. 10, so that the lens adapter 3 moves downward and simultaneously the wheels 42 at an upper part are separated from the inner wall of the tubular way 6. In this case, the remaining 4 wheels 42 at a lower part are in contact with the tubular way 6, so that the investigation system 1 may be preferably inserted further or recovered.

[41] In the supporting unit 4, force transmitted to the respective supporting dies 43 having the wheels 42 by the operation of the driving element 41 is equal via the balance of the force, so that the optical axis of the lens adapter 3 is kept in the center of the tubular way 6 always. The balance of the force is kept continuously even in spite of deformation of the tubular way 6, so that the optical axis of the lens adapter 3 is in the center of the tubular way 6 always and the lens adapter 3 serves to observe and photograph the forward views or the surface of the inner wall of the tubular way at a same distance in the orthogonal direction.

[42] Although the foregoing description has been made with reference to the preferred embodiments, it is to be understood that changes and modifications of the present invention may be made by the ordinary skilled in the art without departing from the spirit and scope of the present invention and appended claims.

Claims

[1] A method for simultaneously outputting images of internal front and lateral sides of a pipe, in which a camera mounted to an investigation system moving forward along an internal wall of a tubular way photographs and transmits data, the data is displayed on a screen via an image processing unit of a computer, and an image for defects or damaged parts determined from moving situations based on the displayed images is output, comprising the steps of: inputting images for front views of the tubular way in a front center portion of a lens adapter mounted in a front part of the camera to transmit the input images to the camera; transmitting images for an inner wall of the tubular way in the range of 360° perpendicular to a peripheral surface of the lens adapter to the camera, wherein the images are incident to a side surface of the lens adapter and reflected the lens adapter to the camera; and dividing the images received from the camera to image data for the front views and the inner wall via the data processing unit and simultaneously displaying and drawing both of the data into a single image.

[2] The method according to claim 1, wherein the image data for the front views among the images input to the image processing unit is displayed as a part corresponding to a circle in the center, and the image data for the inner wall of the tubular way is displayed in the shape of doughnut corresponding to an outer ring, so that both of the image data are displayed and drawn as a single image.

[3] The method according to claim 1 or claim 2, wherein the image in the center is partially expanded for use in the observation of the front views in the image processing, and the outer ring part is corrected and collected via image correction and distortion compensation methods for errors and distortion caused by photographing procedure and camera characteristics, so that a developed image or a developed drawing for the entire tubular way may be obtained.

[4] A device for simultaneously outputting images of internal front and lateral sides of a pipe, wherein the images are output from those photographed by a camera mounted to an investigation system moving forward along an internal wall of a tubular way and displayed on a screen via an image processing unit of a computer, comprising: a supporting unit for coupling the camera to a periphery of the investigation system and having wheels contacting the inner wall of the tubular way variably for positioning the camera in the center of the tubular way; a lens adapter coupled in a front part of the camera for simultaneously obtaining images for front views and images in a direction perpendicular to the inner wall of the tubular way by transmitting the images to the camera; and a data processing unit for outputting the images simultaneously received from the camera into front images and inner wall images into a single image representing both of the front and inner wall images divisionally.

[5] The device according to claim 4, wherein the lens adapter includes a transparent cylindrical case coupled in the front part of the camera, a curved lens disposed at a rear part in the case, a reflection element disposed in a front part in the case and formed in a curved or plane surface shape corresponding to the curved lens, and a center lens disposed in the center of the reflection element for forward views.

[6] The device according to claim 4, wherein the supporting unit includes unit supporting dies disposed at two positions with a predetermined distance from each other and respectively having an end coupled with a peripheral surface of the investigation system and the other end coupled with a group of three wheels, a disc plate or a connection die for making the wheels of the unit supporting dies contact the inner wall surface of the tubular way to position the camera and the lens adapter in the center of the tubular way or separate the camera and the lens adapter from the inner wall for recovery or simple movement, and a driving element coupled with the disc plate or the connection die for driving the disc plate or the connection die.

[7] The device according to claim 6, wherein the driving element is formed of any one of a hydraulic cylinder, an air cylinder or a reduction motor.