How to scan a buildings

Carrying out engineering and geodetic work involves the use of special devices. For their production, the latest achievements of many branches of science are used, including optics, electronics, and mechanics. One of the recent inventions was the electronic laser reflectorless total station. Such a device greatly simplified the performance of many geodetic tasks, increased the efficiency of the work of specialists in the field of architectural measurements. In comparison with previously used measuring systems, the appearance of a new type of total station has increased productivity by three times. How to scan a room? Let’s have a look below.

Although new devices appeared quite recently, they soon could not cope with all the demands of modern construction. There was a need not only for the accuracy of coordinate measurements, but also for the construction of digital models of objects. As it turned out in practice, this requires much more information than standard total stations can give. Three-dimensional laser scanning of buildings has become the only optimal solution to this problem. With its help, it was possible to achieve maximum detail of objects, which made it possible to obtain accurate digital models and images.

What is laser scanning?

3D laser scanning of objects is the latest method for obtaining 2D and 3D models of the surrounding space. During the operation of the devices, a cloud of points with spatial coordinates is created, which ultimately give a three-dimensional image.

How to 3d scan a building? The principle of operation of a laser scanner can be compared with the operation of any radar. It consists in the emission of a laser beam, which has a high frequency, and its reflection on an oscillating mirror. So, the beam reaches the object, and then returns to the starting point again. At this moment, the device fixes the return time, according to which it receives data on the distance at which the object is located. This creates a point cloud. At the same time, it is worth noting that the device can send many rays at once, that is, instantly obtain information about a significant part of the object at once.

Unlike the use of a total station, this method of surveying is non-contact and highly automated. The device contains a special servo drive that independently rotates the measuring head in the horizontal and vertical planes. The specialist no longer needs to press any buttons to turn on the rangefinder or record the received coordinates, look for a target through the eyepiece of the total station, rearrange equipment from place to place, etc. Now all the necessary measurements can be taken from one point without sacrificing accuracy.

Main types of laser scanning

Depending on the complexity of the object, its size and technical features, the following types of laser shooting can be offered to you:

1. Terrestrial laser scanning. It is produced using a static device. Visualization of the object occurs by pointing the sight, or by preliminary scanning at a low density of coordinate points. Then a more detailed modeling of each individual surface takes place and all the data obtained are collected into a single array. This type of work does not require the installation of additional reflectors, marks or markers.
2. Mobile scanning. Shooting takes place with the help of all the same devices, but they are attached to the vehicle. It, in turn, moves along the established route to collect the necessary data. The devices themselves have built-in tilt and vibration compensators, and are also very rigidly attached to their “carrier”. All this helps to avoid any inaccuracies that could arise due to the implementation of shooting in motion.
3. Scanning from the air. This type of work is considered the fastest and most detailed. You can set a certain tiering in order to be able to make 3d scanning a building with infrastructure objects, the earth’s surface, buildings, etc.

Types and features of laser scanners

The laser 3D scanner is capable of taking up to a million measurements in one second. The resulting point cloud can then be displayed as a 2D or 3D image. The main characteristics of the device are indicators of accuracy, range, speed of data collection, as well as the viewing angle. The choice in favor of one or another scanner depends on the technological requirements of the object under study.

 The following options are currently available:

1. Medium range scanners. Range up to 100 m, an error of a few millimeters is acceptable.
2. Long-range scanners. In work, they allow an error from several millimeters to several centimeters, they work with a range of hundreds of meters.
3. Surveying scanners. Range – more than a kilometer, error – up to a decimeter.

Spheres of use of three-dimensional modeling

Three-dimensional scanning of objects allows you to create digital models not only of individual buildings and structures, but also of entire complexes or territories. You have an opportunity to get accurate data even when you work with complex architectural forms. There are  various scientific research, restoration of monuments, where these methods are used.

Laser scanning is also used to solve the following problems:

• Creation of a three-dimensional real estate cadastre;
• design or topographic survey of infrastructure elements, industrial facilities;
• creation of 3D relief models, complex technological objects;
• preservation of data on architectural heritage;
• shooting of facades of any complexity;
• monitoring objects;
• collect data for further use.

In fact, laser scanning of buildings and structures is a universal technology, however, there are a number of tasks for which it is the only possible solution. So, for example, when designing the reconstruction of a building or monitoring its construction, only this method will allow you to get an up-to-date digital model at each stage. Also, high automation guarantees greater accuracy and reliability of information in architectural measurements, geodetic surveys of interiors and facades of buildings.

Separately, it is worth mentioning the use of laser scanning when shooting objects of transport infrastructure. The advantage of the method is that there is no need to stop the movement to use it. So, you can get data on the status of various transport facilities – bridges, tunnels, roads – without any inconvenience. This is often necessary for the creation of topographic plans, electronic databases, design of reconstruction or repair work.

Terrestrial laser scanning allows geodetic control in the mining industry. So, with the help of modern instruments, it is possible to obtain accurate data on mines, tunnels, open workings, etc. At the same time, landslide processes can be controlled, and the stability of the sides can be checked.

In archeology, 3d laser scanning buildings are in demand in order to preserve accurate data on the monuments under study. This information can be used both for scientific purposes and as a virtual museum. Scanning is also used to fix finds and excavation sites.