JP3119012U - Dedicated borehole TV camera for creating a hole wall unfolded image by image processing forward video video in the hole using computer software - Google Patents

Abstract

An optical machine and an electronic device structure of a borehole camera for creating a hole wall developed image are simplified and the cost is reduced, and the borehole camera is easily used.
The present invention is a borehole camera that takes a forward view digital video moving image in a borehole and obtains a hole wall developed image from the moving image data by image processing software. In the image processing, orientation determination and camera rotation correction are performed. This is a borehole camera.
Means for simplifying the structure of the photographing window and the optical system is to obtain sufficient illuminance by inclining each LED illumination 20 around the CCD camera inward and hitting the light cone against the hole wall several cm beyond the camera head, The image is sharpened using a lens having a deep depth of field. As a result, the structure of the photographing window / camera head is made flat glass to simplify the structure 18.
[Selection] Figure 1

Description

  In the present invention, it is possible to observe the inner wall of a survey boring hole having an inner diameter of several tens to several hundred mm, the inside of a boring hole for construction such as an anchor or a pile, and the inside of a well, and a hole wall developed image by image processing. It relates to a suspended survey TV camera (borehole TV camera) to be created.

There are the following techniques as conventional techniques related to the present invention.
Japanese Patent No. 1-210594 JP-A-9-31835 JP 2004-336287 A

  A simple conventional borehole TV camera is called a borehole TV (BHTV), which is a reverse periscope type borehole TV camera in which a plane mirror is placed obliquely under the camera facing the bottom of the hole and the side is viewed. The creation of the hole wall development image is a composition of many single images, and it takes a lot of time for the composition, and it is difficult to create a smooth image. For this reason, although the following apparatus is complicated and expensive, the following borehole camera which develops a hole wall deployment image on the spot with the borehole television camera and image processing apparatus carried in the spot has been developed.

  Borehole image processor (BIP): A conical mirror is placed under the same camera as above, and a full range image of a specific range is taken in a fixed direction, and a circular scan is performed with a computer brought to the site based on this image. A system that rearranges the pixels of the line and synchronizes with the movement of the camera in the hole, and displays a full-scale developed image on the TV screen. (See Patent Document 1)

  Borehole scanner (BSS): A beam of light rotating at high speed along the hole wall is applied to the hole wall, while the camera itself is lowered to detect reflected light in a color image. A system that synthesizes this reflected light into a continuous developed image by converting it into a scanning line inside the controller.

  Borehole line camera (BLC): A line prism is used to detect a full-circle image at an arbitrary position as a color image for one scanning line, and convert the image to a position synchronized with the descent speed of the camera, thereby continuously developing images. System to synthesize.

  In addition, in order to create a seamless and oriented hole wall development image, it is necessary to control that the optical axis of the camera deviates from the center of the hole and that the camera rotates. And a method of controlling the rotation of the camera by rotating it with a small precision motor in the camera, or a method of adjusting the cutout position of the developed image using data from the direction sensor in the probe (for example, patents) Reference 2) has been used.

  Simplification of these camera control mechanisms is an important issue in reducing the size and cost of the camera. For this reason, it is possible to easily obtain a hole wall unfolded image with the same direction regardless of the rotation of the camera. In order to reduce the size, weight, and cost, a directional indicator is installed on the front center axis of the camera, and the surrounding hole wall and directional indicator are photographed as a single image. Based on the above, a plurality of concentric scan lines are set and pixels are read out along each scan line. Then, the position of the direction indicator marker of the direction indicator is detected from the color information of the pixel, the pixel memory of the hole wall image is rearranged based on the marker position, and the rearranged hole wall pixel data is moved to the camera. There has been invented a borehole television camera that creates an image of the entire circumference of a hole wall by accumulating in synchronization. (See Patent Document 3)

  However, a conventional borehole TV camera device for creating a developed hole wall image is a dedicated electronic precision machine that performs complex optical systems such as convex mirrors and conical prisms, and rotational control of the camera and image processing for creating developed images on the spot. It was difficult to make adjustments, and repair adjustments on site were often difficult. In addition, the equipment is expensive, and therefore, the cost of shooting and creating a developed image is high, and the unit price (price / depth length of the developed image) is similar to or close to the drilling core drilling unit price (price / drilling length). However, it is not used for many general geological surveys except for large-scale construction and special purpose geological surveys, and construction management using boring. For this reason, it is a problem to simplify the optical system and mechanical structure of the borehole camera for creating a hole wall developed image and to reduce the cost, and to make it easy to use.

Borehole camera device specializes in downward-facing forward video shooting. For example, in the case of an inner diameter of φ66 mm (standard inner diameter of civil engineering geological survey borehole in Japan), the band-shaped ring part located about 5-10 cm below the camera is well illuminated In addition, the camera has a deep depth of field and is in focus. The developed image is created by image processing using installed software after the front video digital moving image data is saved as an AVI file in a personal computer. (See related patent documents 1 and 2 below)
(Related Patent Document 1) Japanese Patent Application Laid-Open No. 2003-009144 “System for Converting Video Image into Digitized Panorama Image and Converting it to Database and Computer Processing Program Therefor”
(Related Patent Document 2) Japanese Patent Application Laid-Open No. 2003-032674 “System for automatically generating continuous unfolded still image from video image of inner wall of tubular object”

  The present invention is a borehole camera body made of rust-proof metal with built-in CCD camera, LED lighting, and direction sensor, and 3-4 leaf springs that connect to the body to make an integral probe and place the camera in the center of the borehole Metal or plastic cylinder (referred to as center riser) (Fig. 1), tripod and pulley, and depth counter (rotary encoder) that assists in inserting a multi-core cable connecting the borehole camera and input / output arithmetic unit (interface) into the borehole ), A system consisting of a cable drum with slip ring, connecting a digital video camera and TV monitor of a commercial home appliance to the input / output device. For this reason, the borehole camera system is simple and the cost of the apparatus can be reduced.

  The advanced image processing technology used for creating the hole wall development is a two-stage image processing called “pipe projection” and “Mobifix” (the concept is shown in FIG. 3). In the pipe projection, the narrow rings 34 and 47 of the front moving image in the pipe 33 by the borehole camera 32 are coordinate-converted into a thin strip image 35. Mofix is a technology that mosaics this belt-like image and automatically generates a continuous image 36 with no breaks (software that creates a continuous high-resolution, still image by stitching together about 30 still images per second) . This technology can create a developed image of a long hole wall surface of several tens to several hundreds of meters in a short time from a small-bore diameter pipe such as a sewage pipe or a forward video of a tubular object. (See Related Patent Document 2)

  Each LED illumination 20 around the CCD camera is tilted inward by varying the angle (the angle between the borehole axis direction and the LED optical axis is about 5 to 30 °). At φ66 mm, the light cone is applied to the hole wall several centimeters to several tens of centimeters away from the camera head to obtain sufficient illuminance, and the image is sharpened using a lens having a deep depth of field. This eliminates the need for special convex reflectors or conical prisms of conventional cameras and a cylindrical transparent tube that is the outer shooting window, and makes the shooting window / head as a screw cap with flat glass and waterproof packing. Borehole camera with simplified structure 17 and 18.

  A borehole camera that has a built-in small magnetic orientation sensor 21, displays the orientation on the video camera screen with angle numbers 51 and dots 50, and creates seamless developed images on a personal computer that captures the captured digital video. An orientation sensor dot 50 is displayed in the vicinity of a narrow ring used for image processing of a video image, the dot is traced on the developed image 55, and an orientation line 56 is determined on the created developed image and drawn. Borehole camera.

The present invention is a borehole camera that captures a forward-viewing digital video movie in a borehole and obtains a hole wall developed image from the movie data using image processing software. It simplifies the structure of the shooting window and the optical system, and determines the orientation and camera. This is a borehole camera that performs rotation correction by image processing software.
Conventionally, borehole cameras that can create hole wall development images are expensive because the machine itself and the usage fee are similar or close to the drilling core drilling unit price, and are expensive. It hasn't been used much in the survey.
However, since the borehole camera of the present invention is a low-cost development image creation system, rock joints, cracks and landslide surfaces (so-called discontinuous surfaces) in general civil engineering / resource geological surveys with a depth of several to 100 m, It is possible to easily acquire the data of the directionality and opening width of the geological structure having the directionality such as the vein.
Furthermore, the borehole camera of the present invention has a simple structure, so it is a tough machine with few failures, and it can be used for construction management of work using boring excavation, such as confirmation of anchoring layer and support layer of anchor work and pile foundation work. It can be used.

  As the borehole camera, for example, a camera having a CCD camera 19 having a deep depth of field having a light amount adjustment mechanism from the ground or a manual focus mechanism and waterproof mechanisms 17 and 18 is manufactured. The cylindrical device (probe) to be inserted into the boring hole consists of a stainless steel camera body 11 and resin or metal center risers 16 and 25 with springs for installing the camera in the center of the boring hole. With respect to the standard hole diameter of φ66 mm, the outer diameter is about 40 to 55 mm and the total length is about 0.5 m to 1 m.

  The photographing system includes a borehole camera 27, a depth counter (rotary encoder type) 33, an input / output arithmetic unit (interface) 29, a recording digital video camera 30, and a color television monitor 31 for checking images. In order to reduce the overall cost of the system, video cameras and television monitors use commercially available household appliances. The input / output arithmetic unit 29 displays the azimuth and distance information numerically on the liquid crystal screen, and also has a 46 role shown in the figure by synthesizing it with the hole front view image.

  It is indispensable to enter an orientation by orientation measurement in the hole wall developed image, and a magnetic orientation sensor 21 is incorporated to detect the posture of the camera body. The azimuth sensor detects an absolute azimuth based on the geomagnetism, and obtains the azimuth by calculating the biaxial values of the X axis and the Y axis that are output during measurement. Although the azimuth sensor has been used conventionally, in the present invention, a small sensor having a size of several millimeters developed for incorporation into a GPS for a mobile phone is used.

  Depth measurement depth, that is, positional information from the hole mouth ground surface is indispensable for the developed image. The camera depth is wide, with high-strength cables 26 and 63 (multi-core image and control signal cables) with screen / image transmission network assembly, which are connected to the borehole camera and hanging the probe body, placed in the borehole. The rotary movement distance is measured by the rotary encoders 28, 40, 65 connected to the axis of the rotary disk.

  The focusing mechanism is, for example, a lens having a deep depth of field or a manual focusing mechanism. The φ66 mm hole has a mechanism that focuses on the hole wall surface that is about 50 mm or more deep from the front end of the camera.

  The azimuth and depth display mechanism includes a central processing unit 41, an image synthesis circuit 43, a liquid crystal numerical display 42, and a video camera image display function incorporated in a ground input / output device (interface unit) 44.

  FIG. 5 shows an example of an outline 46 of the forward-view video image screen. On the moving image in the hole, numerical values of an angle (unit: degrees) 51 and a depth (unit: m) 52 of the magnetic north direction are synthesized (impose). Further, the azimuth sensor dot 50 is displayed in the vicinity of the narrow ring 47 used for image processing of a video moving image.

  A developed image is created by closely relating the moving image in the hole, the azimuth angle number 51, the dot display 50 on the image, and the depth number (m) 52. The azimuth sensor dot 50 near the narrow ring used for video image processing is traced 55 in the developed image, and the azimuth line 56 is determined and drawn on the developed image.

1 is an overall structure diagram of a probe of a borehole television camera of the present invention. 1 is a schematic diagram of a shooting system for a borehole television camera specialized for forward-looking shooting in the present invention. It is explanatory drawing of the hole wall expansion | deployment image processing technique (Unexamined-Japanese-Patent No. 2003-032674) used by this invention. It is a block diagram explaining the signal processing of the borehole television camera used by this invention. The example of a display of the azimuth | direction and the depth of the forward view video screen of the borehole television camera in this invention is shown. It is explanatory drawing which shows the method of determining an azimuth | direction on the hole wall surface expansion image by the borehole TV camera of this invention. It is a flowchart regarding the Example of imaging | photography with a borehole television camera and hole wall surface expansion image creation in this invention.

Explanation of symbols

10 Borehole camera probe (all)
11 Borehole camera body 12 Center riser (Cylinder with a spring that places the borehole camera in the center of the hole)
17 Waterproof camera head 18 Flat transparent glass 19 CCD camera
20 White LED for illumination
21 Small magnetic orientation sensor 23 Waterproof connector 26 Multi-core cable for image and signal transmission 27 Borehole camera 28 Depth counter (rotary encoder)
29 Input / output arithmetic unit (including azimuth signal central arithmetic unit and image synthesis circuit)
30 Digital video camera (household appliance type)
31 Monitor Color TV (Household appliance type)
33 Tubular objects or boreholes
34, 35, 36 Composition of developed image 46 Front view video image screen 50 Orientation sensor dot 53 Hole wall developed image 55 Orientation sensor dot locus 56 Magnetic north orientation determined on developed image 58 Boring hole (bore hole)
59 Water level in hole 61 Tripod 62 Exclusive pulley 64 Cable drum 69 Battery (DC power supply 12V)
71 Personal computer with built-in image processing software

Claims (3)

Borehole camera specialized in shooting forward-viewing video in the borehole. It is a general-purpose digital video camera for home use that is distributed in the general market as a digital video moving image of forward-viewed images in the borehole in the air and water. At the same time, the azimuth data is displayed by the magnetic azimuth sensor in the camera, and the camera depth position (m) being inserted is superimposed on the image by the rotary encoder type depth counter at the boring hole. Converted to AVI file on personal computer, saved, and created hole wall developed image by image processing software (Japanese Patent Laid-Open No. 2003-032674 “System for automatically generating continuous developed still image from video image of inner wall of tubular object”) In this way, the conventionally developed borehole camera shooting and development image Simplify the equipment and work of formation, bore-hole camera to lower prices. Tilting each LED illumination around the CCD camera inward, tilting the angle of each LED illumination inward (the bore hole depth direction and the angle between the LED optical axis are about 5 to 30 °), civil engineering in Japan At a typical hole diameter of 66 mm in geological survey boreholes, a light cone is applied to the hole wall several centimeters to several tens of centimeters away from the camera head to obtain sufficient illuminance, and from a camera head using a lens with a deep depth of field. A digital video moving image is sharpened by focusing well on a hole wall of several centimeters or deeper. This eliminates the need for special convex reflectors or conical prisms for conventional borehole cameras and a cylindrical transparent tube corresponding to the shooting window on the outside, and simplifies the structure of the shooting window and head using waterproof flat glass. Borehole camera. Built-in small magnetic azimuth sensor, azimuth is displayed with angle numbers and dots on the video camera screen, and a seamless developed image with a fixed azimuth with the camera rotation corrected by the image processing software of the personal computer from the captured digital video movie Borehole camera that creates. A borehole camera that displays azimuth sensor dots in the vicinity of a narrow ring used for video image processing, traces these dots in the developed image, and determines and draws azimuth lines on the created developed image. In this way, using the image processing technology, the camera structure is compared with the conventional structure where the rotation of the camera is controlled by rotating a small precision motor in the camera using a mechanical compass or electromagnetic azimuth sensor in the camera. Borehole camera that realizes simplification and cost reduction.

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