CN115420198B - A BIM-based ancient building three-dimensional laser scanning device and its use method - Google Patents

Abstract

The invention discloses a BIM-based three-dimensional laser scanning device for an ancient architecture and a use method thereof, which are characterized in that a plurality of three-dimensional laser scanners are used for simultaneously carrying out multi-azimuth fixed-point scanning on the ancient architecture to obtain initial point cloud images, and a positioning device is matched for adjusting scanning coordinates of each three-dimensional laser scanner and then carrying out secondary fixed-point scanning, so that the laser scanning device for avoiding or reducing the moving times is used, the moving times are fewer, the laser point cloud images needing to be spliced are fewer, the image integration speed is higher, and compared with the movable scanning, the fixed-point scanning mode is adopted, so that the situation that some detail contents of the target ancient architecture cannot be scanned due to the too high moving speed is avoided.

Description

A BIM-based ancient building three-dimensional laser scanning device and its use method

Technical Field

The present invention relates to a BIM-based ancient building three-dimensional laser scanning device and a method for using the same, and relates to a BIM-based device for three-dimensional laser scanning of ancient buildings, and belongs to the field of laser scanning technology. In particular, it relates to a laser scanning device and a method for using the same, which simultaneously performs multi-directional fixed-point scanning of ancient buildings by multiple three-dimensional laser scanners to obtain an initial point cloud image, and cooperates with a positioning device to adjust the scanning coordinates of each three-dimensional laser scanner and then performs a secondary fixed-point scanning to avoid or reduce the number of movements.

Background technique

Utilizing 3D laser scanning technology, accurate and complete 3D information of ancient buildings can be collected in a non-contact manner, which can be digitally archived and used as a basis for the repair and restoration of ancient buildings. This is of great significance for the protection of ancient buildings. At present, when using 3D laser scanning devices to scan ancient buildings, a handheld scanner is usually required to perform mobile scanning of the ancient buildings and items in the ancient buildings to obtain a laser point cloud map of the ancient buildings. All laser point cloud maps are then stitched together to form a comprehensive laser point cloud file, which is then modeled using 3D software. However, this scanning method requires a certain amount of redundancy between the point cloud maps before stitching, and when using algorithms to compare these redundancies, sufficient similarities need to be analyzed before stitching can be performed. The image integration speed is slow, and when performing mobile scanning, if the scanning speed is too fast, data may be missing and the images may not fit together, requiring rescanning, which is time-consuming and laborious.

Publication No. CN111306424A discloses a three-dimensional laser scanner for building ancient building models, comprising: a base, a screw rod is provided inside the base and four groups of screw rods are arranged, the four groups of screw rods are distributed in the middle of the four sides of the base, the ends of the screw rods are connected to the first driven gear and a toothed disc is provided in the middle of the base, the toothed disc and the first driven gear are meshed with each other, and a sliding block is provided on the surface of the screw rod. The device performs mobile scanning of ancient buildings through the rotation of the three-dimensional laser scanner, but this scanning method requires a certain amount of redundancy between the various point cloud images before splicing, and when using an algorithm to compare these redundancies, it is necessary to analyze enough similar points before splicing can be performed, and the image integration speed is slow. In addition, when performing mobile scanning, if the scanning speed is too fast, it is likely to cause data missing and the images will not fit together, and re-scanning is required, which is time-consuming and labor-intensive.

Publication No. CN108509696A discloses a method and device for monitoring the health of ancient buildings based on three-dimensional laser scanning technology, including obtaining structural coordinate information and material information of the ancient building; obtaining the evaluation result of the structural coordinate information and material information of the ancient building according to the preset ancient building health evaluation rule; and outputting the evaluation result step. The device obtains the structural coordinate information and material information of the ancient building through a three-dimensional laser scanner, but this scanning method requires a certain amount of redundancy between each point cloud map before splicing, and when using an algorithm to compare these redundancies, it is necessary to analyze enough similar points before splicing can be performed. The image integration speed is slow, and when performing mobile scanning, if the scanning speed is too fast, it is likely to cause data missing and the images cannot fit together, and re-scanning is required, which is time-consuming and labor-intensive.

Summary of the invention

In order to improve the above situation, the present invention provides a BIM-based three-dimensional laser scanning device for ancient buildings and a method for using the same. A laser scanning device and a method for using the same are provided, which simultaneously performs multi-directional fixed-point scanning of ancient buildings through multiple three-dimensional laser scanners to obtain an initial point cloud image, and cooperates with a positioning device to adjust the scanning coordinates of each three-dimensional laser scanner and then performs a secondary fixed-point scanning, thereby avoiding or reducing the number of movements.

The present invention is a BIM-based 3D laser scanning device for ancient buildings. The present invention is implemented as follows: The present invention is a BIM-based 3D laser scanning device for ancient buildings, which consists of a fixed-point coordinate rod, a fixed plate, a hollow cross base, a bottom plate, a limit ring, an obliquely placed cylinder, a bending sleeve, a 3D laser scanner, a retracted side baffle, an optical fiber transmission line, a rotating shaft, a line fixing sleeve, a central processing unit and a fixed plug rod. The bottom plate is a circular structure, the hollow cross base is placed at the center of the bottom plate, the positioning coordinate rod is placed at the center of the hollow cross base, the four base arms of the hollow cross base are respectively connected to one end of the four obliquely placed cylinders in a one-to-one correspondence, the top length of the four base arms of the hollow cross base is half of the bottom length, the angle between the obliquely placed cylinder and the bottom plate is 60 degrees, the other end of the obliquely placed cylinder is inserted into one end of the bending sleeve, the limit ring sleeve is placed in the lower middle part of the obliquely placed cylinder, and the limit ring is provided with an annular groove, which corresponds to one end of the bending sleeve. , the other end of the bending sleeve is connected to the three-dimensional laser scanner through a fixing plate, the central processing unit is placed in the hollow cross base, and is located in the middle of the hollow cross base, the four wire fixing sleeves correspond to the four base arms of the hollow cross base one by one, the wire fixing sleeve is fixed in the corresponding base arm through a support, and is close to the end of the corresponding base arm, one end of the wire fixing sleeve is located in the corresponding base arm, and the other end is horizontally extended for a distance and then bent upward and placed in the oblique placement cylinder, the bending portion of the wire fixing sleeve is an arc structure, the rotating shaft is rotatably placed in the oblique placement cylinder, and winding side baffles are correspondingly arranged at both ends of the rotating shaft, the extension line of the other end of the wire fixing sleeve is tangent to the rotating shaft, one end of the optical fiber transmission line is connected to the central processing unit, and the other end passes through the wire fixing sleeve in turn, is placed on the rotating shaft and is connected to the three-dimensional laser scanner, a display screen is arranged on the three-dimensional laser scanner, a locator is arranged on the three-dimensional laser scanner, and the locator is connected to the three-dimensional laser scanner through a power cord;

The present invention also relates to a method for using a BIM-based ancient building three-dimensional laser scanning device, and the specific steps are as follows:

1) Determine the scanning station and place the tripod according to the actual situation of the target ancient building to be scanned;

2) Place the laser scanning device on the tripod bracket, and use the space formed by the fixed-point coordinate rod and the base plate as the basic coordinate system. The fixed-point coordinate rod is the y-axis, and the straight lines where the center lines of the two perpendicular base arms of the cross hollow base of the base plate are located are the x-axis and z-axis;

3) According to the scope of the ancient building to be scanned, three or four 3D laser scanners are stretched, and the locator determines the spatial position coordinates of the corresponding 3D laser scanner and transmits them to the central processor through the light transmission line;

4) The central processor transmits the spatial coordinates of each 3D laser scanner to the computing device, and the computing device transforms the spatial position coordinates of all 3D laser scanners into the basic coordinate system;

5) Obtain the laser point cloud map of the ancient building through fixed-point scanning by each 3D laser scanner and transmit it to the computer equipment;

6) The computer device analyzes whether the position of each 3D laser scanner needs to be adjusted based on the position of each 3D laser scanner in the basic coordinate system and the image matching results between each laser point cloud map. If so, the adjusted coordinates of the 3D laser scanner need to be determined and displayed on the display screen;

7) The staff adjusts the corresponding 3D laser scanner to the corresponding position, and then transmits the laser point cloud map of the ancient building obtained after the second fixed-point scanning to the computer equipment;

8) Computer equipment performs data splicing on the obtained laser point cloud images. The principle of data splicing is to perform image matching processing based on the common surface parts contained in two adjacent laser point cloud images. After the common parts in the two adjacent laser point cloud images are completely overlapped, the surface contours of the ancient buildings scanned by the two 3D laser scanners complement and extend each other. After the laser point cloud images are spliced together, a new comprehensive laser point cloud file is formed and 3D modeling is performed;

9) The computer equipment analyzes the 3D modeling results. If the computer equipment has included all the contents of the target ancient building to be scanned, the scanning work is completed. If the computer equipment has not included all the contents of the target ancient building to be scanned, the computer equipment needs to transmit the 3D modeling results to the display screen for display;

10) The staff adjusts the position of the 3D laser scanner according to the displayed results, and then repeats steps 3-9. Generally, adjusting 1 to 2 times is enough to include all the contents of the target ancient building to be scanned.

Beneficial Effects

1. The number of movements is less, fewer laser point cloud images need to be stitched together, and the image integration speed is faster.

Second, compared with mobile scanning, the fixed-point scanning method will not cause the inability to scan some details of the target ancient building due to the fast moving speed.

3. Simple structure, convenient and practical.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a three-dimensional structural diagram of a BIM-based ancient building three-dimensional laser scanning device of the present invention;

FIG2 is a schematic structural diagram of a BIM-based ancient building three-dimensional laser scanning device according to the present invention;

FIG3 is a three-dimensional structural diagram of a BIM-based ancient building three-dimensional laser scanning device of the present invention when in use.

In the attached figure

The components include: a fixed-point coordinate rod (1), a fixing plate (2), a hollow cross base (3), a bottom plate (4), a limiting ring (5), an oblique placement cylinder (6), a bending sleeve (7), a three-dimensional laser scanner (8), a retracting side baffle (9), an optical fiber transmission line (10), a rotating shaft (11), a line fixing sleeve (12), and a central processing unit (13).

Detailed ways:

The present invention provides a BIM-based ancient building three-dimensional laser scanning device, which is realized in this way. The device comprises a fixed-point coordinate rod (1), a fixed plate (2), a hollow cross base (3), a bottom plate (4), a limit ring (5), an oblique placement cylinder (6), a bending sleeve (7), a three-dimensional laser scanner (8), a retracting side baffle (9), an optical fiber transmission line (10), a rotating shaft (11), a line fixing sleeve (12), a central processing unit (13) and a fixed plug rod. The bottom plate (4) is a circular structure, the hollow cross base (3) is placed at the center of the bottom plate (4), and the positioning coordinate rod is placed at the hollow cross base. At the center of the base (3), the four base arms of the hollow cross base (3) are respectively connected to one end of the four inclined tubes (6) in a one-to-one correspondence, the top length of the four base arms of the hollow cross base (3) is half the bottom length, the angle between the inclined tube (6) and the bottom plate (4) is 60 degrees, the other end of the inclined tube (6) is inserted into one end of the bending sleeve (7), the limiting ring (5) is sleeved at the middle lower position of the inclined tube (6), the limiting ring (5) is provided with an annular groove, the annular groove corresponds to one end of the bending sleeve (7), and the other end of the bending sleeve (7) is connected to the bottom of the bending sleeve (7). The central processing unit (13) is placed in the hollow cross base (3) and is located in the middle of the hollow cross base (3). The four wire fixing sleeves (12) correspond to the four base arms of the hollow cross base (3) one by one. The wire fixing sleeves (12) are fixed in the corresponding base arms through the support and are close to the ends of the corresponding base arms. One end of the wire fixing sleeve (12) is located in the corresponding base arm, and the other end extends horizontally for a distance and then bends obliquely upward and is placed in the oblique placement cylinder (6). The bending portion of the wire fixing sleeve (12) is an arc-shaped structure. The rotating shaft (11) is rotatably placed in the inclined placement cylinder (6), and retracting side baffles (9) are correspondingly placed at both ends of the rotating shaft (11), the extension line of the other end of the wire fixing sleeve (12) is tangent to the rotating shaft (11), one end of the optical fiber transmission line (10) is connected to the central processing unit (13), and the other end passes through the wire fixing sleeve (12) in turn and is placed on the rotating shaft (11) and connected to the three-dimensional laser scanner (8), the three-dimensional laser scanner (8) is provided with a display screen, and the three-dimensional laser scanner (8) is provided with a positioner, and the positioner is connected to the three-dimensional laser scanner (8) through a power line;

Preferably, the fixed-point coordinate rod (1) is made of ceramic material;

Ceramic materials refer to a type of inorganic non-metallic material made from natural or synthetic compounds through forming and high-temperature sintering. It has the advantages of high melting point, high hardness, high wear resistance, and oxidation resistance. It can be used as structural materials and tool materials. Because ceramics also have some special properties, they can also be used as functional materials.

Preferably, the bottom plate (4) is made of austenite-ferrite duplex stainless steel, and is coated with a layer of wear-resistant coating on the surface;

The so-called duplex stainless steel is that the ferrite phase and the austenite phase each account for about half in its solid solution structure, and the content of the minor phase generally needs to reach 30%. In the case of low C content, the Cr content is 18%~28%, and the Ni content is 3%~10%. Some steels also contain alloying elements such as Mo, Cu, Nb, Ti, and N. This type of steel has the characteristics of both austenitic and ferritic stainless steels. Compared with ferrite, it has higher plasticity and toughness, no room temperature brittleness, and significantly improved intergranular corrosion resistance and welding performance. At the same time, it also maintains the 475℃ brittleness of ferritic stainless steel and high thermal conductivity, and has the characteristics of superplasticity. Compared with austenitic stainless steel, it has high strength and significantly improved resistance to intergranular corrosion and chloride stress corrosion;

When in use, in the initial state, one end of the bending sleeve (7) is inserted into the annular slot. When it is necessary to scan the ancient building, the scanning device is placed on the tripod through the bottom plate (4). The staff moves the three-dimensional laser scanner (8), the bending sleeve (7) and the inclined placement tube (6) are separated, the optical fiber transmission line (10) is stretched, and the rotating shaft (11) is driven to rotate, so that the optical fiber transmission line (10) is laid out to a length matching the three-dimensional laser scanner (8). The locator locates the three-dimensional laser scanner (8) and transmits the positioning result to the central processor (13) through the optical transmission line. Then the staff holds the three-dimensional laser scanner (8) to scan the target ancient building. After scanning, the bending sleeve (7) is placed on the inclined placement tube (6), and one end of the bending sleeve (7) is clamped in the annular slot for storage.

The steps of using a BIM-based ancient building three-dimensional laser scanning device of the present invention are as follows:

1) Determine the scanning station and place the tripod according to the actual situation of the target ancient building to be scanned;

2) placing the laser scanning device on the tripod support, taking the space formed by the fixed-point coordinate rod (1) and the base plate (4) as the basic coordinate system, the fixed-point coordinate rod (1) as the y-axis, and the straight lines where the center lines of the two perpendicular base arms of the cross hollow base of the base plate (4) are located as the x-axis and the z-axis;

3) According to the scope of the ancient building to be scanned, three or four three-dimensional laser scanners (8) are stretched, and the locator determines the spatial position coordinates of the corresponding three-dimensional laser scanner (8) and transmits it to the central processor (13) through the light transmission line;

4) The central processing unit (13) transmits the spatial coordinates of each three-dimensional laser scanner (8) to the computing device, and the computing device transforms the spatial position coordinates of all three-dimensional laser scanners (8) into a basic coordinate system;

5) Obtaining a laser point cloud image of the ancient building through fixed-point scanning by each 3D laser scanner (8) and transmitting it to a computer device;

6) The computer device analyzes whether the position of each 3D laser scanner (8) needs to be adjusted based on the position of each 3D laser scanner (8) in the basic coordinate system and the image matching results between each laser point cloud image. If so, the adjusted coordinates of the 3D laser scanner (8) need to be determined and displayed on the display screen;

7) The staff adjusts the corresponding three-dimensional laser scanner (8) to the corresponding position, and then transmits the laser point cloud image of the ancient building obtained after the second fixed-point scanning to the computer device;

8) Computer equipment performs data splicing on the obtained laser point cloud images. The principle of data splicing is to perform image matching processing based on the common surface parts contained in two adjacent laser point cloud images. When the common parts in the two adjacent laser point cloud images are completely overlapped, the surface contours of the ancient buildings scanned by the two three-dimensional laser scanners (8) complement and extend each other. After the laser point cloud images are spliced together, a new comprehensive laser point cloud file is formed and three-dimensional modeling is performed;

9) The computer equipment analyzes the 3D modeling results. If the computer equipment has included all the contents of the target ancient building to be scanned, the scanning work is completed. If the computer equipment has not included all the contents of the target ancient building to be scanned, the computer equipment needs to transmit the 3D modeling results to the display screen for display.

10) The staff adjusts the position of the 3D laser scanner (8) according to the displayed results, and then repeats steps 3-9. Generally, one to two adjustments are enough to include all the contents of the target ancient building to be scanned;

The hollow cross base (3) cooperates with the oblique placement cylinder (6) to support the bending sleeve (7) when scanning is not required, thereby supporting and accommodating the three-dimensional laser scanner (8) thereon;

The design that the top length of the four base arms of the hollow cross base (3) is half the bottom length can ensure that the inner diameter of the inclined tube (6) is not restricted by the height of the hollow cross base (3), thereby avoiding the situation that the inclined tube (6) is insufficiently strong due to the small inner diameter, thus affecting the stable support of the bending sleeve (7);

The limiting ring (5) cooperates with the annular groove to allow the bending sleeve (7) to be inserted into the annular groove, thereby limiting the position of the bending sleeve (7) and preventing the bending sleeve (7) from being displaced due to vibration or the like when it is sleeved on the inclined placement tube (6), thereby preventing the bending sleeve (7) from being unable to stably support the three-dimensional laser scanner (8);

The line fixing sleeve (12) cooperates with the rotating shaft (11) to guide the optical fiber transmission line (10) and then reel it in, so that the optical fiber transmission line (10) can change its length as the position of the three-dimensional laser scanner (8) changes, thereby realizing data transmission between the three-dimensional laser scanner (8) and the central processing unit (13);

The design of the extension line at the other end of the wire fixing sleeve (12) being tangent to the rotating shaft (11) enables the optical fiber transmission line (10) to be guided by the wire fixing sleeve (12) and wound around the rotating shaft (11) without bending, thereby avoiding friction with the side wall of the wire fixing sleeve (12) and easy damage;

The purpose is to obtain an initial point cloud image by simultaneously performing multi-directional fixed-point scanning on the ancient building using multiple three-dimensional laser scanners (8), and to perform a secondary fixed-point scan after adjusting the scanning coordinates of each three-dimensional laser scanner (8) in conjunction with a positioning device, thereby avoiding or reducing the number of movements.

The above embodiments are preferred embodiments of the present invention. In order to save space, the applicant only uses one embodiment, but this is not intended to limit the scope of the present invention. Any ordinary technician in this field can make some improvements without departing from the scope of the present invention. That is, all equivalent improvements made according to the present invention should be covered by the scope of the present invention.

It should be further pointed out that, when describing the above specific embodiments, for the sake of simplicity and clarity, only the differences between the above specific embodiments are described, but those skilled in the art should know that the above specific embodiments themselves are also independent technical solutions.

Claims (9)

1. A three-dimensional laser scanning device for ancient buildings based on BIM, characterized in that the laser scanning device is composed of a fixed-point coordinate rod, a fixed plate, a hollow cross base, a bottom plate, a limiting ring, an obliquely placed cylinder, a bending sleeve, a three-dimensional laser scanner, a retracted side baffle, an optical fiber transmission line, a rotating shaft, a line fixing sleeve, a central processing unit and a fixed plug rod. The bottom plate is a circular structure, the hollow cross base is placed at the center of the bottom plate, the positioning coordinate rod is placed at the center of the hollow cross base, the four base arms of the hollow cross base are respectively connected to one end of the four obliquely placed cylinders in a one-to-one correspondence, the other end of the obliquely placed cylinder is inserted into one end of the bending sleeve, the limiting ring is placed in the lower middle part of the obliquely placed cylinder, the limiting ring is provided with an annular groove, the annular groove corresponds to one end of the bending sleeve, and the other end of the bending sleeve is connected to the fixed plate and the three-dimensional laser scanner The central processing unit is placed in a hollow cross base and is located in the middle of the hollow cross base. The four wire fixing sleeves correspond to the four base arms of the hollow cross base one by one. The wire fixing sleeves are fixed in the corresponding base arms through the supports and are close to the ends of the corresponding base arms. The rotating shaft is rotatably placed in the oblique placement cylinder. The two ends of the rotating shaft are correspondingly provided with retracting side baffles. The extension line of the other end of the wire fixing sleeve is tangent to the rotating shaft. One end of the optical fiber transmission line is connected to the central processing unit, and the other end passes through the wire fixing sleeve in turn and is placed on the rotating shaft and connected to the three-dimensional laser scanner. The three-dimensional laser scanner is provided with a display screen, and the three-dimensional laser scanner is provided with a locator. The locator is connected to the three-dimensional laser scanner through a power cord. The method for using the three-dimensional laser scanning device for ancient buildings based on BIM is characterized by comprising the following steps: 1) Determine the scanning station and place the tripod according to the actual situation of the target ancient building to be scanned; 2) Place the laser scanning device on the tripod bracket, and use the space formed by the fixed-point coordinate rod and the base plate as the basic coordinate system. The fixed-point coordinate rod is the y-axis, and the straight lines where the center lines of the two perpendicular base arms of the cross hollow base of the base plate are located are the x-axis and z-axis; 3) According to the scope of the ancient building to be scanned, three or four 3D laser scanners are stretched, and the locator determines the spatial position coordinates of the corresponding 3D laser scanner and transmits them to the central processor through the light transmission line; 4) The central processor transmits the spatial coordinates of each 3D laser scanner to the computing device, and the computing device transforms the spatial position coordinates of all 3D laser scanners into the basic coordinate system; 5) Obtain the laser point cloud map of the ancient building through fixed-point scanning by each 3D laser scanner and transmit it to the computer equipment; 6) The computer device analyzes whether the position of each 3D laser scanner needs to be adjusted based on the position of each 3D laser scanner in the basic coordinate system and the image matching results between each laser point cloud map. If so, the adjusted coordinates of the 3D laser scanner need to be determined and displayed on the display screen; 7) The staff adjusts the corresponding 3D laser scanner to the corresponding position, and then transmits the laser point cloud map of the ancient building obtained after the second fixed-point scanning to the computer equipment; 8) Computer equipment performs data splicing on the obtained laser point cloud images. The principle of data splicing is to perform image matching processing based on the common surface parts contained in two adjacent laser point cloud images. After the common parts in the two adjacent laser point cloud images are completely overlapped, the surface contours of the ancient buildings scanned by the two 3D laser scanners complement and extend each other. After the laser point cloud images are spliced together, a new comprehensive laser point cloud file is formed and 3D modeling is performed; 9) The computer equipment analyzes the 3D modeling results. If the computer equipment has included all the contents of the target ancient building to be scanned, the scanning work is completed. If the computer equipment has not included all the contents of the target ancient building to be scanned, the computer equipment needs to transmit the 3D modeling results to the display screen for display; 10) The staff adjusts the position of the 3D laser scanner according to the displayed results, and then repeats steps 3-9. Generally, adjusting 1 to 2 times is enough to include all the contents of the target ancient building to be scanned. 2. According to the BIM-based three-dimensional laser scanning device for ancient buildings as described in claim 1, it is characterized in that the top length of the four base arms of the hollow cross base is half the bottom length. 3. According to the BIM-based ancient building three-dimensional laser scanning device according to claim 1, it is characterized in that the angle between the inclined cylinder and the bottom plate is 60 degrees. 4. A BIM-based ancient building three-dimensional laser scanning device according to claim 1, characterized in that one end of the wire fixing sleeve is located in the corresponding base arm, and the other end extends horizontally for a distance and then bends obliquely upward and is placed in the oblique placement tube. 5. According to the BIM-based ancient building three-dimensional laser scanning device according to claim 4, it is characterized in that the bending part of the wire fixing sleeve is an arc structure. 6. According to the BIM-based three-dimensional laser scanning device for ancient buildings described in claim 5, it is characterized in that the extension line of the other end of the wire fixing sleeve is designed to be tangent to the rotating shaft, so that the optical fiber transmission line will not bend when it is wound on the rotating shaft after being guided by the wire fixing sleeve, thereby avoiding friction with the side wall of the wire fixing sleeve and easy damage. 7. According to the BIM-based three-dimensional laser scanning device for ancient buildings as described in claim 1, it is characterized in that when in use, multiple three-dimensional laser scanners are used to simultaneously perform multi-directional fixed-point scanning on the ancient buildings to obtain an initial point cloud image, and a positioning device is used to adjust the scanning coordinates of each three-dimensional laser scanner before performing a secondary fixed-point scanning to avoid or reduce the number of movements. 8. According to the BIM-based ancient building three-dimensional laser scanning device described in claim 1, it is characterized in that the line fixing sleeve cooperates with the rotating shaft to guide and then reel the optical fiber transmission line, so that the optical fiber transmission line can change its length as the position of the three-dimensional laser scanner changes, thereby realizing data transmission between the three-dimensional laser scanner and the central processing unit. 9. According to the BIM-based ancient building three-dimensional laser scanning device described in claim 1, it is characterized in that the hollow cross base cooperates with the oblique placement cylinder to support the bending sleeve when scanning work is not needed, and then support and store the three-dimensional laser scanner thereon.