Laser scanning is a very common technique for surveying using a computer based Electronic Distance Measurement (also known as EDM) devices. Some examples of the tools used in the past are a total station and smart pole, but nowadays, a surveyor will normally use a tripod mounted scanner or a hand held device for real-time measurement of three dimensional objects. The reflecting beam allows for high precision capture of objects, buildings and landscapes, minimizing data collection errors, while saving time and money, which makes it a great alternative to the more traditional methods of surveying.
The difference between the two is that the tripod mounting 3D scanner would require multiple set-ups and a surveyor would have to aim directly at the target object. Handheld 3D scanner captures tens of thousands of points per second by detecting the reflection of the laser beam from the target object, thus it is capable of capturing data from a large object without multiple set-ups, greatly reducing survey time.
The scanner will produce a data file containing a set of data points in a three-dimensional system of coordinates, also known as a 3D point cloud. 3D point cloud can be later converted into computer-aided design model (CAD) through process of surface reconstruction. With the addition of high resolution 360 degree photography that captures surface texture and colors, the finished result is a full 3D model of the target object.
360 degree photography is a technique of taking pictures using high class software or specialized equipment that captures images with elongated fields of view. Simply it means that an image has an aspect ratio of at least 2:1 or more. In other words, the image is at least twice as wide as it is high. There are various methods you can use to achieve a 360 images – from rotating lens cameras to segmented and 3D panoramas. High resolution 360 photographs present the holistic and realistic view of objects, whereas two dimensional photographs have limited view. The 360 degree images can be easily zoomed in to view more details or zoomed out for an overview.
Mapping of the 360 degree photographs onto the CAD model obtained by the 3D laser scanning, creates a powerful time and cost effective surveying tool that not only records high precision data, but allows for a virtual “walkthrough”. The combination of the two has already found its uses in various industries – from entertainment to aerospace, from archaeological site reconstruction, historical artifacts documentation and analysis to building design, remodeling and renovations.
Another interesting uses for both, 3D laser scanning and 360 degree photography are crime scene investigations. The entire crime scene can be reconstructed on the computer along with any evidence markers. Integrating the 3D model with 360 photographs provides the investigators with a chance to look at the scene from the bird’s point of view to reconstruct the events, or to zoom in and study any particular feature in more detail.