CN-122015643-A - Laser scanning ancient building structure data acquisition method and system

CN122015643ACN 122015643 ACN122015643 ACN 122015643ACN-122015643-A

Abstract

The application provides a method and a system for acquiring structural data of a laser scanning ancient building, which relate to the technical field of laser scanning and can calculate the scanning range of a scanner in real time by acquiring a preset key monitoring area in the ancient building and real-time spatial position and posture information of the laser scanner. On the basis, a three-dimensional bounding box intersection algorithm is adopted to carry out real-time space geometric matching calculation on the scanning range and the key monitoring area, so that whether an overlapping relationship exists is judged. And intelligently marking the acquired point cloud data as high-value data or common-value data according to the overlapping relation. According to the application, high-value data is written into the high-priority cache queue, common value data is written into the common priority cache queue, and differential cache management and transfer strategies are executed on the data in the two queues, so that the dynamic monitoring task of the ancient architecture can be effectively carried out, and the problem that the model loses analysis value due to data loss or time stamp disorder is avoided.

Inventors

ZHAO HUA
GUO YUZE
HAO YINGZHI
YANG LINGXIAO
XING YAN

Assignees

山西大同大学

Dates

Publication Date: 20260512
Application Date: 20260127

Claims (10)

1. The method for collecting the data of the historic building structure by laser scanning is characterized by comprising the following steps of: Acquiring a preset key monitoring area in an ancient building, and acquiring real-time spatial position and posture information of a laser scanner; calculating the scanning range of the laser scanner in real time according to the real-time space position and the gesture information; performing real-time space geometrical matching calculation on the scanning range of the laser scanner and the key monitoring area to obtain an overlapping relation, wherein the real-time space geometrical matching calculation adopts a three-dimensional bounding box intersection algorithm; if the overlapping relation exists, the point cloud data collected by the laser scanner are marked as high-value data, and if the overlapping relation does not exist, the point cloud data collected by the laser scanner are marked as common value data; And writing the point cloud data marked as high-value data into a high-priority cache queue, writing the point cloud data marked as common-value data into a common-priority cache queue, and executing differentiated cache management and transfer strategies on the data in the high-priority cache queue and the common-priority cache queue.
2. The method for collecting data of a laser scanning historic building structure according to claim 1, wherein the step of performing real-time space geometrical matching calculation on the scanning range of the laser scanner and the key monitoring area to obtain an overlapping relationship, and the step of adopting a three-dimensional bounding box intersection algorithm for the real-time space geometrical matching calculation comprises the following steps: calculating a three-dimensional space bounding box of a scanning range of the laser scanner; And carrying out space overlapping judgment on the three-dimensional space bounding box of the scanning range of the laser scanner and the preset three-dimensional space bounding box of each key monitoring area, and if the projections of the three space bounding boxes on the X, Y, Z coordinate axes overlap, then an overlapping relationship exists.
3. The method for collecting data of a laser scanning historic building structure according to claim 1, wherein the step of performing differentiated cache management and dump policies on the data in the high priority cache queue and the normal priority cache queue comprises: the highest writing and reading authority is given to the high-priority cache queue, and the data in the priority queue are transferred to the main storage device; when the buffer memory space is tense, the memory space is released preferentially from the common priority buffer memory queue, the operation of releasing the memory space comprises suspending writing new data into the queue, covering the historical data in the queue, and degrading and storing the data in the queue to any one of auxiliary memory devices; The occupation states of the high-priority cache queue and the common-priority cache queue and the load of the main storage device are dynamically monitored, and the write-in bandwidth allocation strategies of the two queues are adjusted in real time, wherein when the high-priority cache queue has data waiting for writing, the write-in bandwidth of the high-priority cache queue is preferentially ensured, and the write-in operation of the common-priority cache queue is interrupted if necessary.
4. The method for collecting data of a laser scanning historic building structure according to claim 1, wherein the step of writing point cloud data marked as high-value data into a high-priority cache queue comprises: Carrying out real-time analysis processing on point cloud data marked as high-value data, and identifying whether redundant point cloud clusters exist or not; if the redundant point cloud cluster does not exist, writing point cloud data marked as high-value data into a high-priority cache queue; If the redundant point cloud cluster exists, carrying out information compression and feature abstract generation on the redundant point cloud cluster to obtain a refined data packet, and writing the refined data packet into a high-priority cache queue.
5. The method for collecting data of a laser scanning historic building structure according to claim 4, wherein the step of analyzing and processing the point cloud data marked as high-value data in real time to identify whether redundant point cloud clusters exist comprises the steps of: Calculating a point set in a preset radius neighborhood according to the point cloud data; Calculating local three-dimensional variance and average normal vector of the point set; And when the number of the point sets exceeds a preset number threshold, the three-dimensional variance is lower than the preset variance threshold, and the normal vector included angle is smaller than a preset angle threshold, judging the point set as a redundant point cloud cluster.
6. The method for collecting data of a laser scanning historic building structure according to claim 4, wherein if there is a redundant point cloud cluster, the step of performing information compression and feature summary generation on the redundant point cloud cluster to obtain a refined data packet comprises: Extracting representative points from the redundant point cloud clusters, wherein the representative points adopt average coordinates of all points or an original point nearest to the center; calculating and recording local geometric feature parameters of the redundant point cloud cluster to obtain an information abstract, wherein the local geometric feature parameters comprise an average normal vector, local curvature, bounding box size and original points; and obtaining a refined data packet according to the representative point, the information abstract and a small amount of strategically sampled point cloud data.
7. The method for collecting data of a laser scanning historic building structure according to claim 1, wherein the step of performing real-time space geometrical matching calculation on the scanning range of the laser scanner and the key monitoring area to obtain an overlapping relationship, and the step of using a three-dimensional bounding box intersection algorithm for the real-time space geometrical matching calculation includes: acquiring the obtained point cloud data of the key monitoring area according to the local overview scanning of the laser scanner, and updating the reference coordinates of the key monitoring area; Acquiring real-time spatial position and attitude information of a laser scanner in real time, and predicting a scanning track of the laser scanner in a future period; geometric analysis is carried out on the predicted scanning track and the updated reference coordinates of the key monitoring area, and whether a deviation trend exists or not is judged; If the deviation trend exists, generating a scanning path adjustment instruction, wherein the adjustment instruction adopts a proportional-integral-derivative control algorithm, the input is the deviation amount, the output is the scanner motion parameter adjustment amount, and the motion parameter adjustment amount comprises a horizontal rotation speed adjustment amount, a pitching angle adjustment amount or a scanning sector range adjustment amount; And adjusting the scanning path or the scanning sector of the laser scanner in real time according to the scanning path adjusting instruction.
8. The method for acquiring data of a laser scanning historic building structure according to claim 7, wherein the step of acquiring the obtained point cloud data of the key monitoring area according to the laser scanner local overview scanning and updating the reference coordinates of the key monitoring area comprises: performing feature matching and local registration on point cloud data obtained by local overview scanning of a laser scanner and a digital model of a preset key monitoring area, wherein the feature matching and the local registration are realized by adopting an iterative nearest point algorithm; Calculating the offset of the key monitoring area relative to the initial position; And updating the reference coordinates of the key monitoring area according to the offset.
9. The method for collecting data of a laser scanning historic building structure according to claim 7, wherein the step of geometrically analyzing the predicted scanning trajectory and the reference coordinates of the updated key monitoring area to determine whether there is a departure trend, geometrically analyzing the predicted scanning trajectory and the reference coordinates of the updated key monitoring area, and determining whether there is a departure trend includes: Calculating the minimum distance between the predicted scanning track and the boundary of the key monitoring area; And when the minimum distance is smaller than a preset critical deviation threshold value, judging that a deviation trend exists.
10. A laser scanning ancient building structure data acquisition system for gather ancient building structure data, its characterized in that, this system includes: The information acquisition module is used for acquiring a preset key monitoring area in the ancient building and acquiring real-time spatial position and posture information of the laser scanner; the scanning range calculation module is used for calculating the scanning range of the laser scanner in real time according to the real-time space position and posture information; the overlapping relation judging module is used for carrying out real-time space geometric matching calculation on the scanning range of the laser scanner and the key monitoring area to obtain an overlapping relation, and the real-time space geometric matching calculation adopts a three-dimensional bounding box intersection algorithm; The data marking module is used for marking the point cloud data acquired by the laser scanner as high-value data if the overlapping relation exists, and marking the point cloud data acquired by the laser scanner as common value data if the overlapping relation does not exist; The differential cache processing module is used for writing point cloud data marked as high-value data into a high-priority cache queue, writing point cloud data marked as common-value data into a common-priority cache queue, and executing differential cache management and transfer strategies on the data in the high-priority cache queue and the common-priority cache queue.

Description

Laser scanning ancient building structure data acquisition method and system Technical Field The application relates to the technical field of laser scanning, in particular to a method and a system for collecting data of an ancient building structure through laser scanning. Background When digital protection and structural analysis are performed on an ancient architecture structure, a three-dimensional laser scanning technology is widely applied to acquiring high-precision data of the architecture surface. The technology emits a laser beam by a laser scanner and receives a reflected signal, thereby generating a large amount of point cloud data. These point cloud data are typically transmitted in real time over a data line to a field portable workstation for processing and storage. To cope with the large amount of data generated by the scanner, the workstation generally configures a cache region, quickly writes the original point cloud data stream into the cache region, and then gradually transfers the original point cloud data stream to the main storage device by a background program. This procedure performs steadily in conventional scanning tasks. However, when the object to be scanned is an ancient building with extremely complicated structure, particularly, a wooden structure such as an arch, liang Fang, or a carved pattern on sparrow, the scanning accuracy needs to be adjusted to an extremely high level in order to accurately build a model reflecting the fine structure. This results in a dramatic increase in the density of the point cloud collected per unit area, and an explosive increase in the data flow rate output from the scanner. Existing data transfer and caching systems face tremendous pressures, and the speed at which the cache area is filled far exceeds the speed at which data is transferred to the primary storage device, and the system quickly blocks. In order to avoid data overflow loss, the acquisition software can only frequently pause scanning operation and can continue after waiting for the data in the buffer area to be emptied. The stop-and-go acquisition mode greatly prolongs the field operation time, and more seriously, for the task of building a model capable of reflecting the change of a structure at different time points, the interruption breaks the continuity of data in time, so that the finally obtained model loses analysis value. Further analysis finds that the existing caching method considers all the acquired point cloud data as being equally important, and adopts a simple first-in first-out sequential writing and restoring strategy. This strategy results in a large amount of low value data such as flat walls with simple description and high repeatability, and occupies valuable buffer space and write bandwidth. While high value data describing key structural details such as exquisite woodcarving is forced to wait because the buffer is full, even increasing the risk of being discarded. This problem is particularly acute when the task goal is to build a model that reflects the structural changes. For example, to monitor small deformations of the critical beam, successive scans are required at different points in time. At this time, the point cloud data reflecting the deformed region is most valuable. However, the existing caching mechanism cannot identify the key data, and may delay processing high-value data due to busy transferring low-value data, so that the complete process of structural change cannot be captured in time, and finally, when the data is compared before and after the model is built, data loss or time stamp disorder occurs, so that the health condition of the ancient building cannot be accurately estimated, and the dynamic monitoring task is meaningless. Disclosure of Invention The application provides a method and a system for collecting data of an ancient architecture structure by laser scanning, and aims to solve the problems that in the prior art, when fine structural data of the ancient architecture is collected, a buffer system is blocked and data transmission is interrupted due to rapid increase of data quantity, and high-value data and low-value data cannot be effectively distinguished, so that data collection efficiency and data continuity are affected, and a dynamic monitoring task is meaningless. In one aspect, the application provides a laser scanning ancient architecture structure data acquisition method, which comprises the following steps: Acquiring a preset key monitoring area in an ancient building, and acquiring real-time spatial position and posture information of a laser scanner; calculating the scanning range of the laser scanner in real time according to the real-time space position and posture information; carrying out real-time space geometric matching calculation on the scanning range of the laser scanner and the key monitoring area to obtain an overlapping relation, wherein the real-time space geometric matching calculation adopts a thre