If you ask which technology that’s truly changing mature industries, even contributing to the introduction of new tech niches, one of the best answers would be laser scanning.
Laser scanning is a measurement method used in surveying and other disciplines to map the shape and dimensions of an object. The resulting data is then rendered onto a computer for further analysis or modelling. It is used on a wide range of applications in a wide range of industries, including 3D printing and building surveys.
We spoke to the City Surveys & Monitoring Ltd about 3D Laser Scanning, and this is what they had to say.
How does laser scanning work?
Applying a method known as LiDAR (Light Detection and Ranging) an individual can work out the shape and location of an object by measuring the amount of light that reflects when a laser is aimed at it.
The method of creating 3D images of surfaces and objects is a complex process but a fairly simple concept. To provide some context, laser scanning can be compared to a connect-the-dots puzzle in three dimensions.
Using a high-precision piece of equipment called a laser scanner equipped with a digital camera a surveyor will gather the data into a complex mesh of points called a point cloud.
There are several terms that refer to the technique of laser scanning: 3DLS (Three Dimensional Laser Scanning), TLS (Terrestrial Laser Scanning) and HDS (High Density Survey) or HDS (High Definition Survey) are all used interchangeably.
Making a model using a point cloud
The point cloud creates a visual representation of the surveyed items for the client. It is an invaluable reference document, especially when the surrounding environment is too hazardous, remote, or inaccessible for extended contact. A point cloud offers a way for individuals to interact virtually with any environment and the objects within it.
With the generation of a point cloud, this is where laser scanning really comes into its own. The data measured by the scanner can be converted back into useful 3D items by retracing the lines, objects and surfaces on the cloud with a contour mesh. This make laser scanning a highly-accurate and versatile method of measurement.
Point cloud data may be of use with products such as: meshing, 3D solid models, profile generation, animation and web-based data sharing. It may also be beneficial to create a point cloud if access to a location is inadequate due to permanence, location, safety and time.
For large-scale scanning jobs, a process known as stitching is used. This is where a number of point clouds with similar characteristics are overlapped to produce a bigger cloud. This means a more comprehensive result without compromising on the precision or finer detail of an average size scanning project.
Considerations when scanning
There are a number of factors to take into consideration when scanning:
- Structural interference
- Perpendicular angles
- Wet surfaces
The accuracy of a scan will be affected by comparatively small vibrations. If the client is depending on a highly-detailed scan, then it is imperative that the ground be stable.
It is important to carry out laser scanning as close to the point of focus as possible. Although it is regularly used to measure inaccessible or objects in remote locations, pinpoint accuracy and detail are better achieved the closer the surveyor is to the target.
If other structures impede the line of sight between the target and the scanner, detection by laser is impossible. As the laser must be reflected to obtain a reading, a clear path between the point of origin and the terminus is crucial.
If the angle between the laser and the target is too great, it can produce a distorted result. It is important the scanner be positioned as close to vertical as possible for an accurate result.
As you might expect, the weather is another factor that can affect the outcome of a laser scan. In particular, precipitation, such as rain, fog and snow, can create ‘false reflections’, sending light back to the scanner before it even hits the target.
Similarly, surfaces with a sheen can also be the cause of errors. Wet, metal, glossy or glassy surfaces behave in uncertain ways with light reflection, just like atmospheric conditions.
Laser scanners operate within ‘safe’ temperatures so caution should be exercised when scanning in extremes of hot or cold, and in certain parts of the world as equipment may not function as intended.
Laser scanning technology is very important for the business world. It made 3D printing possible. Not only that, but it’s also changing existing industries, such as building surveys in construction industry, which evolve into 3D surveying.
Now over to you: Which industries that are – or will be – impacted by this technology?