Method for non-constant speed borehole television video mosaicking based on small period speed averaging

Abstract

The application provides a method for non-uniform speed drilling television video puzzle based on small period speed average, which comprises the following steps: obtaining original video and original depth file; reading the original depth file; generating a transient speed file; searching the position of each speed peak within the range of 85% of the amplitude of the speed curve; calculating the average speed within the small period of adjacent peaks; generating a new depth file; performing puzzle calculation by using the new depth file and the original video, cutting annular image segments from the original video according to the depth information, then unfolding the annular images to form strip images, and sequentially splicing each unfolded image according to the hole depth to obtain a two-dimensional puzzle image. The application can solve the problem of poor imaging effect under the working condition of drill rod vibration, and can save more geological information as much as possible.

Description

Technical Field

[0001] This invention relates to the field of geotechnical engineering investigation technology, and in particular to a method for non-uniform borehole video mosaic based on small-cycle velocity averaging. Background Technology

[0002] In recent years, with the rise of horizontal directional drilling technology, storage-type borehole television (BMT) has also emerged, effectively solving the problems of difficult transmission of traditional BMT and the algorithmic issues of omnidirectional structural surface analysis. It has been widely used in the exploration and construction disturbance evaluation of underground engineering projects such as hydropower and mining, as well as slope engineering projects in my country. Using BMT images, various characteristics and fine structures of geological bodies within the borehole can be observed, such as stratigraphic lithology, rock structure, faults, fissures, interlayers, and karst, and geological columnar sections can be compiled.

[0003] However, due to advancements in horizontal drilling technology, drilling depths exceeding 1,000 meters have resulted in borehole curvature caused by directional drilling. During storage-type borehole television (BMT) testing, the system is directly connected to the drill pipe. The drill pipe experiences significant resistance due to its own weight and friction with the borehole wall, leading to periodic vibrations. This results in a "mosaic" effect in the BMT image, producing unclear images and losing much geological information. Summary of the Invention

[0004] This invention provides a method for non-uniform speed borehole television video mosaicking based on small-period velocity averaging. It aims to solve the mosaicking algorithm problem in borehole television under drill rod vibration conditions. Under vibration conditions, there is always a time lag between the depth gauge fixed at the borehole opening and the camera located at the bottom of the drill rod. This means that while the camera is actually moving forward, the depth gauge fails to record it simultaneously. Traditional algorithms assume it is stationary, thus periodically losing many frames, resulting in a "mosaic" phenomenon in the borehole television mosaic, unclear imaging, and the loss of much geological information.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] Methods for non-uniform drilling television video mosaicking based on small-period velocity averaging include:

[0007] S001: Obtain the original video and original depth file;

[0008] S002: Read the raw depth file;

[0009] S003: Generate instantaneous velocity files based on the original depth files;

[0010] S004: Based on the instantaneous velocity file, search for the location of each velocity peak within 85% of the velocity curve amplitude;

[0011] S005: Calculate the average velocity within a small period between adjacent peaks based on the location of each velocity peak;

[0012] S006: Generate a new depth file based on the average velocity within the small cycles of adjacent peaks;

[0013] S007: Perform mosaic calculations using the new depth file and the original video. Based on the depth information, extract the ring-shaped image segment from the original video, then unfold the ring-shaped image to form a strip-shaped image. Finally, stitch each unfolded image together according to the hole depth to obtain a two-dimensional mosaic image.

[0014] In this specification, the error estimation generated by the small-cycle velocity averaging algorithm includes:

[0015] The order of each frame in a 2D jigsaw puzzle remains unchanged.

[0016] Within each small cycle, the starting and ending depths of the image remain unchanged;

[0017] Upper limit estimation of depth error for a single frame image.

[0018] In this manual, an optical camera is installed at the front end of the borehole television probe to record images of the borehole wall reflected back through a conical or curved mirror, forming a continuous raw video.

[0019] In this manual, an electronic compass is installed inside the probe to record the probe's orientation information.

[0020] In this manual, a depth wheel is installed at the borehole opening, and a depth gauge is installed in the depth wheel. The displacement is recorded by the friction between the drill pipe and the depth wheel to form the original depth file.

[0021] In this manual, the formula for generating instantaneous velocity files is as follows:

[0022] ,in Let i be the instantaneous velocity corresponding to sequence i. Let n be the displacement corresponding to the i-th sequence, and n be the total number of depth file sequence numbers.

[0023] In this specification, if the velocity corresponding to the i-th sequence is simultaneously greater than the velocities corresponding to the (i-1)-th and (i+1)-th sequences, then point i is considered a peak, and the i values ​​satisfying the condition are arranged into an array:

[0024] ;

[0025] in The starting sequence number corresponding to the j-th period. Let N be the sequence number corresponding to the j-th peak, and N be the total number of peaks.

[0026] In this manual, the formula for calculating the average velocity within a small period of adjacent peak values ​​is as follows:

[0027] ;

[0028] in, Let m be the instantaneous velocity corresponding to the sequence m after averaging over a small period. Let m be the instantaneous velocity corresponding to sequence m. This is the sequence number corresponding to the (j+1)th peak.

[0029] In this manual, the formula for generating a new depth file is as follows:

[0030] ;

[0031] in This represents the displacement value corresponding to the i-th sequence after averaging within a small period.

[0032] In this specification, the formula for estimating the upper limit of depth error for a single frame image is as follows:

[0033] ;

[0034] in This represents the upper limit of depth error for a single frame of image. The maximum speed within the j-th period. Let be the average velocity during the j-th cycle, and u be the camera sampling interval.

[0035] In summary, the present invention has at least the following beneficial effects:

[0036] This invention can solve the problem of poor imaging effect under drill pipe vibration conditions and can preserve more geological information as much as possible.

[0037] In this invention, the sequential order of each frame of the 2D jigsaw puzzle remains unchanged; within each small cycle, the starting and ending depths of the images remain constant; consequently, the extreme value of the depth error in a single frame is very small and acceptable. Engineering application examples demonstrate the significant advantages of this algorithm. Attached Figure Description

[0038] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 This is a schematic diagram of the method for non-uniform drilling television video mosaic based on small-period averaging involved in this invention.

[0040] Figure 2 This is a schematic diagram of the two-dimensional unfolding of a borehole television, where a is the two-dimensional unfolding diagram of the traditional algorithm and b is the two-dimensional unfolding diagram of the small-period velocity averaging algorithm.

[0041] Figure 3 The diagram shows the process curves of the small-cycle velocity averaging algorithm, where a is a schematic diagram of the original depth curve, b is a schematic diagram of the velocity curve, c is a schematic diagram of the peak detection of the velocity curve, d is a schematic diagram of the velocity curve after small-cycle averaging, and e is a schematic diagram of the velocity curve after small-cycle averaging.

[0042] Figure 4 This is a schematic diagram of the image conversion process.

[0043] Figure 5 This is the user interface. Detailed Implementation

[0044] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the embodiments of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0045] The following disclosure provides many different implementations or examples for carrying out different structures of the embodiments of the present invention. To simplify the disclosure of the embodiments of the present invention, specific examples of components and arrangements are described below. Of course, these are merely examples and are not intended to limit the embodiments of the present invention. Furthermore, reference numerals and / or reference letters may be repeated in different examples of the embodiments of the present invention; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various implementations and / or arrangements discussed.

[0046] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0047] like Figure 1 As shown, this embodiment provides a method for non-uniform drilling television video mosaicking based on small-period averaging. First, the original depth file is converted into a velocity file. Then, the minimum period of the velocity curve is detected, and velocity averaging is performed within the minimum period. This preserves video information while minimizing positional errors, resulting in a better-quality two-dimensional unfolded image. Specifically:

[0048] S001: A high-definition, high-resolution optical camera is installed at the front end of the borehole television probe to record images of the borehole wall reflected by a conical or curved mirror. As the probe moves continuously through the borehole, a continuous raw video is generated. An electronic compass is also installed inside the probe to record its orientation information. A depth wheel with a depth gauge is installed at the borehole opening. Displacement is recorded by the friction between the drill rod and the depth wheel, generating a raw depth file.

[0049] S002: Read the original depth (displacement) file. The depth file consists of sequence number i and the corresponding displacement. composition.

[0050] S003: Generate instantaneous velocity file:

[0051] (1)

[0052] In the formula, Let i be the instantaneous velocity corresponding to sequence i. is the displacement corresponding to the i-th sequence; n is the total number of depth file sequence numbers.

[0053] S004: Search for the location of each velocity peak within the velocity curve amplitude range [0.85, 1]. If the velocity corresponding to the i-th sequence is simultaneously greater than the velocity corresponding to the (i-1)-th and (i+1)-th sequences, then point i is considered a peak. The i values ​​satisfying this condition form the following array:

[0054] (2)

[0055] In the formula, The starting sequence number corresponding to the j-th period. Let N be the sequence number corresponding to the j-th peak, and N be the total number of peaks.

[0056] S005: Average velocity within adjacent peak periods:

[0057] (3)

[0058] In the formula, Let m be the instantaneous velocity corresponding to the sequence m after averaging over a small period. Let m be the instantaneous velocity corresponding to sequence m. This is the sequence number corresponding to the (j+1)th peak.

[0059] S006: Generate a new depth file:

[0060] (4)

[0061] In the formula, This represents the displacement value corresponding to the i-th sequence after averaging within a small period.

[0062] S007: Perform mosaic calculations using the new depth file and the original video. Based on the depth information, extract ring-shaped image segments from the original video, then unfold the ring-shaped images to form strip-shaped images. Finally, stitch each unfolded image together according to the hole depth to obtain a two-dimensional mosaic image. The image conversion process is as follows: Figure 4 As shown.

[0063] Among them, the error estimate generated by the "small cycle speed averaging" algorithm:

[0064] (1) The order of each frame of a two-dimensional jigsaw puzzle will not change.

[0065] (2) Within each small cycle, the starting and ending depths of the image remain unchanged.

[0066] (3) The formula for estimating the upper limit of depth error in a single frame image is:

[0067] ;

[0068] in, This represents the upper limit of depth error for a single frame of image. The maximum speed within the j-th period. Let be the average velocity during the j-th cycle, and u be the camera sampling interval.

[0069] In one specific embodiment:

[0070] In a water conservancy underground powerhouse survey project, horizontal directional boreholes were drilled to a depth of 880.5m and an elevation of 1060m. The designed borehole depth was 900m, and the actual final borehole depth was 880.50m. In the first borehole, the diameter was 122mm, and the drilling reached 160m with a casing length of 160m. In the second borehole, the diameter was 96mm, and the drilling reached 880.50m.

[0071] Storage-type borehole television (BMT) was used for well logging imaging. Due to multiple directional drilling operations, the borehole bent, resulting in significant resistance to the drill pipe. Furthermore, to ensure video quality, the borehole was pre-washed, removing the mud (mainly polyacrylamide) that normally lubricates the borehole. This absence of lubricant between the drill pipe and the borehole wall increased frictional resistance. During testing, the drill pipe exhibited periodic vibrations. Under these vibration conditions, there was a time lag between the depth gauge fixed at the borehole opening and the camera located at the bottom of the drill pipe. This meant that while the camera was actually moving forward, the depth gauge failed to record it simultaneously. Traditional algorithms consider it stationary, leading to the periodic loss of many frames. This resulted in a "mosaic" effect in the borehole television image mosaic, producing unclear images and losing much geological information (see details). Figure 2 (a) in the middle. Figure 2The diagram shows a two-dimensional unfolded borehole television image. In image a, there is a mosaic effect, which makes the structural surface appear jagged. In image b, the structural surface is a smooth and complete sine curve, without the mosaic effect, and the geological information is clearly visible. Figure 3 The curves represent the process of the small-cycle velocity averaging algorithm, where a is the original depth curve; b is the velocity curve, showing a certain degree of periodic vibration; c is the peak detection of the velocity curve, finding the peak and its location information; d is the velocity curve after small-cycle averaging; and e is the velocity curve after small-cycle averaging.

[0072] Therefore, a method based on non-uniform drilling video mosaicking with small-period averaging is used for calculation:

[0073] S001: A high-definition, high-resolution optical camera is installed at the front end of the borehole television probe to record images of the borehole wall reflected by a conical or curved mirror. As the probe moves continuously through the borehole, a continuous raw video is generated. An electronic compass is also installed inside the probe to record its orientation information. A depth wheel with a depth gauge is installed at the borehole opening. Displacement is recorded by the friction between the drill rod and the depth wheel, generating a raw depth file.

[0074] S002: Read the original depth (displacement) file. The depth file consists of sequence number i and the corresponding displacement. Composition. The speed curve for this embodiment is shown below. Figure 3 b in the text.

[0075] S003: Generate instantaneous velocity file:

[0076] (1)

[0077] In the formula, Let i be the instantaneous velocity corresponding to sequence i. is the displacement corresponding to the i-th sequence; n is the total number of depth file sequence numbers.

[0078] The peak detection results of the velocity curve in this embodiment are shown below. Figure 3 c in the text.

[0079] S004: Search for the location of each velocity peak within 85% of the velocity curve amplitude, i.e., the range [0.85, 1] ​​(this setting is to avoid searching for low-amplitude peaks). If the velocity corresponding to the i-th sequence is simultaneously greater than the velocity corresponding to the (i-1)-th and (i+1)-th sequences, then point i is considered a peak. The i values ​​satisfying this condition form the following array:

[0080] (2)

[0081] In the formula, The starting sequence number corresponding to the j-th period. Let N be the sequence number corresponding to the j-th peak, and N be the total number of peaks.

[0082] The velocity curve after small-cycle averaging in this embodiment is shown below. Figure 3 d in the text.

[0083] S005: Average velocity within adjacent peak periods;

[0084] (3)

[0085] In the formula, Let m be the instantaneous velocity corresponding to the sequence m after averaging over a small period. Let m be the instantaneous velocity corresponding to sequence m.

[0086] S006: Generate a new depth file;

[0087] (4)

[0088] In the formula, This represents the displacement value corresponding to the i-th sequence after averaging within a small period.

[0089] The depth curve after small-cycle averaging in this embodiment is shown below. Figure 3 The 'e' in the middle.

[0090] S007: Perform mosaic calculations using the new depth file and the original video. Based on the depth information, extract ring-shaped image segments from the original video, then unfold the ring-shaped images to form strip-shaped images. Finally, stitch each unfolded image together according to the hole depth to obtain a two-dimensional mosaic image. The operation interface is as follows: Figure 5 As shown.

[0091] This embodiment yields a well-formed 2D jigsaw puzzle image (see details). Figure 2 (b) effectively eliminated the mosaic effect and preserved clear information about the rock mass structure.

[0092] Among them, the error estimate generated by the "small cycle speed averaging" algorithm:

[0093] (1) The order of each frame of a two-dimensional jigsaw puzzle will not change.

[0094] (2) Within each small cycle, the starting and ending depths of the image remain unchanged.

[0095] (3) Estimation of the upper limit of depth error for a single frame image:

[0096] (5)

[0097] In the formula, This represents the upper limit of depth error for a single frame of image. The maximum speed in the j-th cycle, in m / min. Let be the average velocity during the j-th cycle, and u be the camera sampling interval in milliseconds.

[0098] In this implementation case, the average test speed is 2 m / min, the maximum speed is 3 m / min, and the sampling interval is 40 ms. Therefore, the maximum depth error of a single frame image is:

[0099] ;

[0100] In geological exploration, centimeter-level errors are negligible, indicating that the depth error introduced by this algorithm is acceptable in engineering practice.

[0101] The embodiments described above are for illustrative purposes only and are not intended to limit the invention. Therefore, any changes in numerical values ​​or substitutions of equivalent elements should still fall within the scope of this invention.

[0102] The above detailed description will enable those skilled in the art to understand that the present invention can indeed achieve the aforementioned objectives and has complied with the provisions of the Patent Law.

[0103] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the invention. The above descriptions are merely preferred embodiments of the invention and are not intended to limit the invention. It should be noted that any modifications, equivalent substitutions, and improvements made within the spirit and principles of the invention should be included within the scope of protection of the invention.

[0104] It should be noted that the above description of the process is for illustrative purposes only and does not limit the scope of this specification. Those skilled in the art can make various modifications and changes to the process under the guidance of this specification. However, these modifications and changes remain within the scope of this specification.

[0105] The basic concepts have been described above. Obviously, for those skilled in the art who have read this application, the above disclosure is merely illustrative and does not constitute a limitation of this application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and corrections to this application. Such modifications, improvements, and corrections are suggested in this application, and therefore, such modifications, improvements, and corrections still fall within the spirit and scope of the exemplary embodiments of this application.

[0106] Furthermore, this application uses specific terms to describe its embodiments. For example, "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic related to at least one embodiment of this application. Therefore, it should be emphasized and noted that "an embodiment," "one embodiment," or "an alternative embodiment" mentioned twice or more in different positions in this specification do not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of this application can be appropriately combined.

[0107] Furthermore, those skilled in the art will understand that aspects of this application can be described and illustrated through several patentable types or situations, including any new and useful combination of processes, machines, products, or substances, or any new and useful improvements thereof. Therefore, aspects of this application can be implemented entirely in hardware, entirely in software (including firmware, resident software, microcode, etc.), or a combination of hardware and software. All of the above hardware or software can be referred to as a “unit,” “module,” or “system.” Furthermore, aspects of this application can take the form of a computer program product embodied in one or more computer-readable media, wherein computer-readable program code is contained therein.

[0108] The computer program code required for the operation of each part of this application can be written in any one or more programming languages, including object-oriented programming languages ​​such as Java, Scala, Smalltalk, Eiffel, JADE, Emerald, C++, C#, VB.NET, and Python; general programming languages ​​such as C; Visual Basic, Fortran2103, Perl, COBOL2102, PHP, and ABAP; dynamic programming languages ​​such as Python, Ruby, and Groovy; or other programming languages. This program code can run entirely on the user's computer, or as a standalone software package on the user's computer, or partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the latter case, the remote computer can be connected to the user's computer via any network, such as a local area network (LAN) or wide area network (WAN), or connected to an external computer (e.g., via the Internet), or in a cloud computing environment, or used as a service such as Software as a Service (SaaS).

[0109] Furthermore, unless expressly stated in the claims, the order of processing elements and sequences, the use of numbers and letters, or other names described in this application are not intended to limit the order of the processes and methods of this application. Although some currently considered useful embodiments of the invention have been discussed in the foregoing disclosure by way of various examples, it should be understood that such details are for illustrative purposes only, and the appended claims are not limited to the disclosed embodiments; rather, the claims are intended to cover all modifications and equivalent combinations that conform to the substance and scope of the embodiments of this application. For example, although the implementation of the various components described above can be embodied in a hardware device, it can also be implemented as a purely software solution, such as an installation on an existing server or mobile device.

[0110] Similarly, it should be noted that, in order to simplify the description of the present application and thus aid in the understanding of one or more embodiments of the invention, the foregoing description of the embodiments of the present application sometimes combines multiple features into a single embodiment, drawing, or description thereof. However, this approach of the present application should not be construed as reflecting an intention that the claimed subject matter requires more features than expressly recited in each claim. Rather, the subject of the invention should possess fewer features than in any single embodiment described above.

Claims

1. A method for non-uniform drilling television video mosaicking based on small-period velocity averaging, characterized in that, include: S001: Obtain the original video and original depth file; S002: Read the raw depth file; S003: Generate instantaneous velocity files based on the original depth files; S004: Based on the instantaneous velocity file, search for the location of each velocity peak within the 85%-100% range of the velocity curve amplitude; S005: Calculate the average velocity within a small period between adjacent peaks based on the location of each velocity peak; S006: Generate a new depth file based on the average velocity within the small cycles of adjacent peaks; S007: Perform mosaic calculations using the new depth file and the original video. Based on the depth information, extract the ring-shaped image segment from the original video, then unfold the ring-shaped image to form a strip-shaped image. Finally, stitch each unfolded image together according to the hole depth to obtain a two-dimensional mosaic image.

2. The method for non-uniform drilling television video mosaicking based on small-period velocity averaging according to claim 1, characterized in that, Error estimation is generated by a small-cycle velocity averaging algorithm, including: The order of each frame in a 2D jigsaw puzzle remains unchanged. Within each small cycle, the starting and ending depths of the image remain unchanged; Upper limit estimation of depth error for a single frame image.

3. The method for non-uniform drilling television video mosaicking based on small-period velocity averaging according to claim 1, characterized in that, An optical camera is installed at the front end of the borehole television probe to record images of the borehole wall reflected back through a conical or curved mirror, forming a continuous raw video.

4. The method for non-uniform drilling television video stitching based on small-period velocity averaging according to claim 1, characterized in that, An electronic compass is installed inside the probe to record the probe's orientation information.

5. The method for non-uniform drilling television video stitching based on small-period velocity averaging according to claim 1, characterized in that, A depth wheel is installed at the borehole opening, and a depth gauge is installed in the depth wheel. The displacement is recorded by the friction between the drill pipe and the depth wheel, forming the original depth file.

6. The method for non-uniform drilling television video mosaicking based on small-period velocity averaging according to claim 2, characterized in that, The formula for generating instantaneous velocity files is: ,in Let i be the instantaneous velocity corresponding to sequence i. Let be the displacement corresponding to the i-th sequence. is the displacement corresponding to the (i-1)th sequence, and n is the total number of depth file sequence numbers.

7. The method for non-uniform drilling television video mosaicking based on small-period velocity averaging according to claim 6, characterized in that, If the velocity corresponding to the i-th sequence is greater than the velocities corresponding to the (i-1)-th and (i+1)-th sequences simultaneously, then point i is considered a peak, and the i-th values ​​satisfying the condition are grouped into an array: ； in The starting sequence number corresponding to the j-th period. Let N be the sequence number corresponding to the j-th peak, and N be the total number of peaks.

8. The method for non-uniform drilling television video mosaicking based on small-period velocity averaging according to claim 7, characterized in that, The formula for calculating the average velocity within a small period of adjacent peaks is: ； in, Let m be the instantaneous velocity corresponding to the sequence m after averaging over a small period. Let m be the instantaneous velocity corresponding to sequence m. This is the sequence number corresponding to the (j+1)th peak.

9. The method for non-uniform drilling television video mosaicking based on small-period velocity averaging according to claim 8, characterized in that, The formula for generating a new depth file is: ； in This represents the displacement value corresponding to the i-th sequence after averaging within a small period. This represents the displacement corresponding to the i=1th sequence.

10. The method for non-uniform drilling television video mosaicking based on small-period velocity averaging according to claim 9, characterized in that, The formula for estimating the upper limit of depth error in a single frame image is as follows: ； in This represents the upper limit of depth error for a single frame of image. The maximum speed within the j-th period. Let be the average velocity during the j-th cycle, and u be the camera sampling interval.

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