Borehole inspection device

Abstract

Borehole inspection device for inspecting a borehole in a workpiece has a measuring head which includes an endoscope and is insertable into the borehole to be inspected and movable relative to the borehole in different axial positions. Borehole inspection device has an imaging optics with a panoramic view for imaging the inner surface of the borehole, and the imaging optics is in image transmission connection with a digital image recorder. Device has a memory for storing the images recorded in different axial positions of the measuring head, and an evaluation apparatus for evaluating the images stored in the memory. In order to obtain surface depth information about the inner surface of the borehole, the evaluation apparatus is configured for evaluating images recorded at different viewing angles of the imaging optics with regard to the particular surface location, using a 3D reconstruction method.

Claims

1. A borehole inspection device for inspecting a borehole in a workpiece, comprising: a) a measuring head including an endoscope insertable into a borehole to be inspected and movable relative to the borehole in different positions, and including an imaging optics with a panoramic view for imaging an inner surface of the borehole, and the imaging optics being in image transmission connection with a digital image recorder; b) a memory for storing the images recorded in different axial positions of the measuring head; c) an evaluation apparatus for evaluating the images stored in the memory; d) the evaluation apparatus being configured for evaluating images recorded at different viewing angles of the imaging optics with regard to a particular surface location, using a 3D reconstruction method in order to obtain surface depth information about the inner surface of the borehole; and e) the evaluation apparatus being configured for evaluating the images recorded at different viewing angles with regard to the particular surface location, using a stereo triangulation method, and the stereo triangulation method being used as the 3D reconstruction method.

2. The borehole inspection device according to claim 1, wherein: a) the different viewing angles with regard to the particular surface location correspond to different axial positions of the measuring head.

3. The borehole inspection device according to claim 2, wherein: a) a feed apparatus which is controllable by a control apparatus is associated with the measuring head in order to set different axial positions, and different viewing angles of the imaging optics, with regard to the particular surface location on the inner wall.

4. The borehole inspection device according to claim 3, wherein: a) the control apparatus transmits position data, which represent the particular axial position of the measuring head, to the evaluation apparatus in order to associate the particular axial position of the measuring head with an image recorded in this position.

5. The borehole inspection device according to claim 1, wherein: a) an illumination apparatus for illuminating an imaging area, detected by the imaging optics on the inner surface of the borehole, in light and/or dark field illumination.

6. The borehole inspection device according to claim 5, wherein: a) the different viewing angles with regard to the particular surface location correspond to different axial positions of the measuring head.

7. The borehole inspection device according to claim 1, wherein: a) a feed apparatus which is controllable by a control apparatus is associated with the measuring head in order to set different axial positions, and thus different viewing angles of the imaging optics, with regard to a surface location on the inner wall.

8. The borehole inspection device according to claim 1, wherein: a) a feed apparatus which is controllable by a control apparatus is associated with the measuring head in order to set different axial positions with regard to a surface location on the inner wall.

9. A borehole inspection method for inspecting a borehole in a workpiece, comprising: a) using a measuring head including an endoscope, and having an imaging optics with a panoramic view for imaging the inner surface of the borehole; b) the imaging optics being in image transmission connection with a digital image recorder, and the measuring head being inserted into the borehole and moved in different axial positions; c) recording images of the inner surface in different axial positions of the measuring head by the digital image recorder; d) storing the images recorded in different axial positions of the measuring head in a memory; e) evaluating the images stored in the memory by an evaluation apparatus; f) evaluating images recorded at different viewing angles of the imaging optics with regard to a surface location on the inner wall by a 3D reconstruction method for obtaining surface depth information about the particular surface location; and g) evaluating the images recorded at different viewing angles by the stereo triangulation method for obtaining surface depth information about the inner surface of the borehole, and the stereo triangulation method being used as the 3D reconstruction method.

10. The borehole inspection method according to claim 9, wherein: a) the different viewing angles with regard to the particular surface location correspond to different axial positions of the measuring head.

11. The borehole inspection method according to claim 9, wherein: a) the measuring head is moved by means of a feed apparatus which is controllable by a control apparatus in order to set different axial positions, and thus different viewing angles of the imaging optics, with regard to a surface location on the inner wall.

12. The borehole inspection method according to claim 11, wherein: a) the control apparatus transmits position data, which represents a particular axial position of the measuring head, to the evaluation apparatus in order to associate the particular axial position of the measuring head with an image recorded in this position.

13. The borehole inspection method according to claim 9, wherein: a) an imaging area detected by the imaging optics on the inner surface of the borehole is illuminated by an illumination apparatus in light and/or dark field illumination.

14. A borehole inspection device for inspecting a borehole in a workpiece, comprising: a) a measuring head including an endoscope insertable into a borehole to be inspected and movable relative to the borehole in different positions, and including an imaging optics with a panoramic view for imaging an inner surface of the borehole, and the imaging optics being in image transmission connection with a digital image recorder; b) a memory for storing the images recorded in different axial positions of the measuring head; c) an evaluation apparatus for evaluating the images stored in the memory; d) the evaluation apparatus being configured for evaluating images recorded at different viewing angles of the imaging optics with regard to a particular surface location, using a 3D reconstruction method in order to obtain surface depth information about the inner surface of the borehole; e) the evaluation apparatus being configured for evaluating the images recorded at different viewing angles with regard to the particular surface location, using a stereo triangulation method, and the stereo triangulation method being used as the 3D reconstruction method; f) the different viewing angles with regard to the particular surface location correspond to different axial positions of the measuring head; and g) a feed apparatus controllable by a control apparatus being associated with the measuring head in order to set different axial positions, and different viewing angles of the imaging optics, with regard to the particular surface location on the inner wall.

15. The borehole inspection device according to claim 14, wherein: a) the control apparatus transmits position data, which represents the particular axial position of the measuring head, to the evaluation apparatus in order to associate the particular axial position of the measuring head with an image recorded in this position.

16. The borehole inspection device according to claim 14, wherein: a) an illumination apparatus for illuminating an imaging area, detected by the imaging optics on the inner surface of the borehole, in light and/or dark field illumination.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows in a highly schematic manner one embodiment of a borehole inspection device according to the invention; and

(2) FIG. 2 shows in a highly schematic manner a conversion of an image, recorded by means of the digital image recorder, into a Cartesian image.

DETAILED DESCRIPTION OF THE INVENTION

(3) FIG. 1 illustrates one embodiment of a borehole inspection device 2 according to the invention for inspecting a borehole in a workpiece 6, having a measuring head 8 which is designed as an endoscope and is insertable into the borehole 4 to be inspected and movable relative to the borehole 4 in different axial positions, and which has an imaging optics 10 with a panoramic view for imaging the inner surface of the borehole 4. The imaging optics is in image transmission connection with a digital image recorder 12.

(4) The device 2 also has a memory 14 for storing the images recorded in different axial positions of the measuring head 8, the memory 14 being in image transmission connection with the digital image recorder 12.

(5) An evaluation apparatus 16 is provided for evaluating the images stored in the memory 14.

(6) In order to move the measuring head 8 relative to the borehole 4 in the axial direction thereof, and thus to axially position the measuring head 8 (double arrow 18), a feed apparatus 22 which is controllable by a control apparatus 20 is provided for the measuring head 8.

(7) The control apparatus 20 is in data transmission connection with the evaluation apparatus 16, and transmits the particular axial position of the measuring head 8 to the evaluation apparatus 16 in order to associate the particular axial position of the measuring head 8 with an image recorded in this position.

(8) For illumination of an imaging area at the inner surface of the borehole 4 which is detected by the imaging optics 10 in light and/or dark field illumination, an illumination apparatus 24 is provided, which in the embodiment includes a ring-shaped light source, for example with a plurality of LEDs. With regard to the design of the illumination apparatus, reference is made to DE 10 2008 009 975 A1 and DE 10 2009 019 459 A1, the entire contents of which are hereby incorporated into the present patent application.

(9) The mode of functioning of the device 2 according to the invention and of the method according to the invention is as follows:

(10) For inspecting the borehole 4, the measuring head 8 together with the imaging optics 10 (imaging optical system) is inserted into the borehole 4, the measuring head 8 being axially positioned in the direction of the double arrow 18 by means of the feed apparatus 22.

(11) Circumferential surface lines on the inner wall of the borehole 4 are imaged by the imaging optics 10 with a panoramic view, as a circle on the image recorder 12.

(12) FIG. 2 symbolically illustrates the sensor surface, denoted by reference numeral 26. Surface lines at different locations in the z direction of the image recorder 10 are imaged at different viewing angles 1 and 2 of FIG. 1. X and y directions, respectively, are likewise shown for reference. General viewing angle (phi) is likewise shown for completeness.

(13) FIG. 1 symbolically illustrates two surface lines, denoted by reference numerals 28 and 30. Peripheral beams which adjoin the viewing angle range of the imaging optics 10 are denoted by reference numerals 32, 34 in FIG. 1.

(14) As shown in the top right area in FIG. 1, in the illustrated position of the measuring head 8 the surface line 28 is viewed at the viewing angle 1, and the surface line 30 is viewed at the viewing angle 2.

(15) To obtain a complete image of the inner surface of the borehole 4, the measuring head 8 is moved axially relative to the borehole 4, and images are recorded at certain intervals. The camera image is read out circularly in each case, and by polar coordinate transformation is converted line-by-line into a Cartesian image, the images recorded in this way being stored in the memory 14.

(16) FIG. 2 symbolically illustrates how surface lines 32, 34 imaged on the sensor surface 2 of the image recorder 12 are converted into Cartesian images 36, 38.

(17) After the measuring head 8 has been inserted into the borehole 4 in the axial direction until the entire axial depth of the borehole is detected, the images stored in the memory 14 represent the entire inner surface of the borehole 4.

(18) It is apparent that during the axial movement of the measuring head 8, each surface location on the inner wall of the borehole 4 is viewed and imaged at different viewing angles in succession, corresponding to the particular axial position of the measuring head 8. To obtain surface depth information, the images recorded at different viewing angles with regard to the particular surface location are evaluated according to the stereo triangulation method.

(19) If an anomaly is identified on the inner wall of the borehole 4 based on the recorded images, it may be established by means of the surface depth information whether this is a depression and thus a surface defect, or is an elevation possibly caused by soiling of an otherwise flawless surface.

(20) The device 2 according to the invention and the method according to the invention thus allow anomalies to be not only detected, but also classified.

(21) One particular advantage of the device 2 according to the invention and the method according to the invention is that the surface depth information is determined from the images that are recorded anyway during an inspection pass. Therefore, obtaining the surface depth information does not require additional time for the inspection.

(22) Identical or corresponding components are provided with the same reference numerals in the various figures of the drawing. If components are omitted in the figures of the drawing for purposes of representation or illustration, the components in question in the other figures are to be supplemented accordingly. It is apparent to those skilled in the art that the features of the individual embodiments are also exchangeable among the embodiments; thus, the features disclosed with respect to one embodiment may also be identically or correspondingly provided in the other embodiments. It is further apparent to those skilled in the art that the features disclosed in the individual embodiments in each case further embody the invention taken by themselves, i.e., independently of the other features of the particular embodiment.

(23) While this invention has been described as having a preferred design, it is understood that it is capable of further modifications, and uses and/or adaptations of the invention and following in general the principle of the invention and including such departures from the present disclosure as come within the known or customary practice in the art to which the invention pertains, and as may be applied to the central features hereinbefore set forth, and fall within the scope of the invention.