Correlation between Incident Angle, Measurement Distance, Object Colour and the Number of Acquired Points at CNC Laser Scanning

Abstract

In this paper the results of research about the influences of the incident angle, the measurement distance and object colour and reflectivity on the number of acquired points while using a lasertriangulation scanner on CNC-machines, are presented. The number of points is an essential parameter of a successful 3D surface reconstruction, although it is rarely considered as a subject of research. In this research we identified the scanning parameters to acquire a sufficient number of points for any surface reconstruction. The causes of the results are also identified and could be considered when creating automatic-measurement strategies for CNC-machines. Finally, the equation for an estimation of the number of acquired points in the optimal area of measuring parameters for the case example is also introduced.

On the influence of scanning factors on the laser scanner-based 3D inspection process

“…This positioning error has a systematic nature and it can be partially controlled by the user thanks to the right positioning of the scanner with respect to the object, being usually the normal position sensor-to-surface the best one. This is also confirmed in [22]. Van Gestel et al [14] found out that the scan depth d has an important influence on systematic and random errors of the laser line scanner on CMM.…”

“…In Vukašinović et al [22], proposed to work with a good diffuse reflection of the surface being scanned. A technical solution more adopted to limit the effects of the ambient lighting is the use of specific light filters on CCD sensor [11].…”

“…In [22], the authors also studied the influence of incident angle, object colour and distance on CNC laser scanning process. The main outcomes of that research were that better results correspond to (i) keeping the sensor-to-surface relative distance constant and to the minimum (so to reduce noise and improve the level of acquired details), and (ii) working with the minimum possible laser power.…”

High-Precision Surface Inspection: Uncertainty Evaluation within an Accuracy Range of 15μm with Triangulation-based Laser Line Scanners

“…Vukasinovic et al [21,22,23] examined the impact of di erent measuring angles and scanner-to-surface distances on the number of acquired points and the measuring noise. Di erent from Xi and Isheil [24,11], they determined a prediction-function with the goal to evaluate the number of points and the measuring noise for any imaging geometry.…”

“…Over the last years, several studies have shown the importance of the analysis of measurement uncertainties [3,7,11,15,20,21,22,23,24]. Thus, Xi et al [24] indicated that various scanner-to-surface distances and inclination angles raise systematic uncertainties for the used sensor.…”