11 mistakes to avoid to obtain good data quality

Gasoline in the car. Checked. Battery charged. Checked. Weather forecast. Checked. The day before, everything was carefully reviewed, the scan on site went well. Back at the office, the data is transferred to the computer. And here is the drama! The point cloud is distorted, images are misaligned and objects appear double! Manual corrections in perspective... How to avoid this pitfall and thus avoid losing a day of work? Explanations.

What exactly do we mean by “poor quality” data?

A poorly performed 3D scan is one which resulting point cloud do not meet the expected criteria of precision, consistency and completeness. Here are some points that can make the use of this data suboptimal:

  1. Distorted or duplicate point cloud: distortions or duplicates in the point cloud will make inaccurate measurements and difficult CAD/BIM operation.
  2. Misaligned images: image alignment errors can create inconsistencies in colorization and make the immersive experience through images unsatisfactory.
  3. Altimeter offsets: an imprecise height distorts the interpretation of the results. Particularly in ultra-precise applications such as the assessment of the flow of a stream.
  4. Lots of measurement noise: interferences adds unwanted points, disturbing the taking of dimensions.
  5. Lack of completeness: missing areas require going back to the field for supplemental work.

The importance of learning to identify causes on site

The causes of the above problems can be varied and often depend on the operating mode chosen (on foot, in vehicle, etc.). Here are the main points to pay attention to to obtain a qualitative scan without manual effort:

  1. Opening and blocking doors: building doors must be opened and blocked before you pass with the machine, in order to avoid interruptions and possible algorithmic stalls.
  2. Inappropriate gait dynamics: sudden movements, jumping or uneven walking can disorient the positioning system. Be careful to spot any obstacles that may be on your way.
  3. Moving Elements: although the Viametris MS-96 can handle moving elements, a narrow environment or people near the operator can disrupt the positioning algorithm. When you are in a complex public environment, it may be a good idea to choose a time and avoid crowds around the machine.
  4. Use in an elevator (yes we have seen it…): going up or down in an elevator with the scanner can cause significant interpretation errors. The question here may be: why scan an elevator with a dynamic scanner? To meditate…
  5. Poor technological choice: using only SLAM in homogeneous outdoor environments without structures is a mistake. Here, it is crucial to connect your GNSS antenna to have a fallback plan just in case.
  6. Excessive speed: the scanner, capable of capturing 960,000 points per second, cannot guarantee millimeter density at high speeds, such as 120 km/h. Be careful to monitor your speed in vehicle mode based on the expected level of detail. Using a speed limiter may be a solution.
  7. Weather conditions: scanning in the rain or on wet ground creates floating spots due to lidar reflections from water drops and puddles. Not very aesthetic…
  8. Accidents and shocks: a shock with an object or a fall of the operator disrupts the positioning algorithm, potentially making the scan inaccurate. Better scanning again the section where the accident took place.
  9. Using the system in reverse mode: scanning backward or with the system on the hood without adjusting the inertial unit parameters can make initialization of the system laborious. Pay attention to the settings before starting your scan.
  10. Improper loops closure: in environments without GNSS and without GCP, it is essential to close loops correctly to limit drift as much as possible.
  11. Reflective surfaces: environments with many mirrors or reflective surfaces can create depth errors, ghosts and thus disrupt positioning algorithms. If possible, it’s best to close the curtains!


If you scan well in the field, there is no reason to have problems in the office. So yes it is very easy to use a dynamic scanner but that is not a reason. Be careful to remain conscientious.

Still unclear methodological points?