“Noise is the deviation of any values from an ideal surface,” explained Sergei Bakunov.
Noise may appear due to low equipment characteristics or due to the surface features of the measured object. For example, it will be quite difficult to take a high-quality photo of a metal surface: the object's outline may be unclear. This problem can be avoided by using high-quality equipment, such as the Leica SX-10 electronic tacheometer.
Removing noise will work in your favor in the future: it will be much easier to create a usa email list high-poly 3D model based on a “clean” point cloud. The development of measurement drawings will also be less labor intensive.
The level of detail of the cloud depends on the density of the concentration of points in one area. Understanding the level of detail is very important to achieve the goal set by the customer. The higher the density, the higher the detail and the more time it will take to scan. High-density point cloud files also take up a lot of storage space.
“If you’re doing laser scanning all the time, you should have about 500 terabytes of storage where you can send it all,” Sergey Bakunov advised his listeners, noting that it’s better to store the scan data for a while, since the customer may request it after the project is completed.
Point cloud color
The point cloud can be created in color or black and white. A black and white point cloud will be sufficient for creating measurement drawings and developing a 3D model.
But if the customer has specified in the requirements that building defects in the form of cracks, chips, etc. be applied to the drawings, then it will be much more difficult to see them in a black and white cloud. Color scanning is just right for this purpose. The disadvantage of color scanning is the long execution time. In addition, it is best done in good lighting.
Shadow areas
Almost any object has moving elements, vegetation and other obstacles that block the equipment's view. This aspect should also be specified in the technical specifications. For example, the presence of shaded areas is allowed in a volume of no more than 20% of the area of the scanned surfaces.
It is important to specify this point because many buildings for which a point cloud needs to be created are abandoned and littered. And if you skip this point in the technical task, the customer may not pay attention to such a state of the buildings. But if he does, he may ask the laser scanning contractor to clear the trash on his own.
Point Cloud Segmentation
Sergey Bakunov emphasized once again that 3D shooting can produce a lot of noise and unnecessary information: vegetation, moving elements, duplicates of elements in the form of reflections obtained when scanning mirror surfaces. To avoid this situation, the customer must specify the composition of the elements he needs in the technical specifications.
Terms of work
The duration of the work depends on the following labor costs:
Filming
The laser scanning contractor calculates the area of the object and, based on this data, determines how much time he will spend on the measurement, taking into account the color of the point cloud, the need for additional photographs of the object and referencing the cloud to the coordinate system.
Processing
The time for registration, “coloring” and segmentation of data by floors, rooms, etc. is calculated.
Result
The time spent on developing measured drawings and a 3D model of the object is also taken into account when calculating the work deadlines.
Final words
Sergey Bakunov concluded his speech with a few words about the cost of the project:
"The market decides how much something costs. We are usually asked to do it cheaply and quickly. A drawing can be done in 15-20 minutes. But here you have to understand that if you want to do it as cheaply and quickly as possible, then you will get a lower quality product."