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Fast Measurement and Reconstruction of Large Workpieces with Freeform Surfaces by Combining Local Scanning and Global Position Data.

Chen Z, Zhang F, Qu X, Liang B - Sensors (Basel) (2015)

Bottom Line: With the multi-sensor data fusion, errors accumulated during the image alignment and registration process are minimized, and the measuring precision is significantly improved.The results prove that this new combined method is promising for measuring and reconstructing the large-scale objects with complex surface geometry.Compared with reported methods of large-scale shape measurement, it owns high freedom in motion, high precision and high measurement speed in a wide measurement range.

View Article: PubMed Central - PubMed

Affiliation: State Key Lab of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, China. cz19902013@sina.com.

ABSTRACT
In this paper, we propose a new approach for the measurement and reconstruction of large workpieces with freeform surfaces. The system consists of a handheld laser scanning sensor and a position sensor. The laser scanning sensor is used to acquire the surface and geometry information, and the position sensor is utilized to unify the scanning sensors into a global coordinate system. The measurement process includes data collection, multi-sensor data fusion and surface reconstruction. With the multi-sensor data fusion, errors accumulated during the image alignment and registration process are minimized, and the measuring precision is significantly improved. After the dense accurate acquisition of the three-dimensional (3-D) coordinates, the surface is reconstructed using a commercial software piece, based on the Non-Uniform Rational B-Splines (NURBS) surface. The system has been evaluated, both qualitatively and quantitatively, using reference measurements provided by a commercial laser scanning sensor. The method has been applied for the reconstruction of a large gear rim and the accuracy is up to 0.0963 mm. The results prove that this new combined method is promising for measuring and reconstructing the large-scale objects with complex surface geometry. Compared with reported methods of large-scale shape measurement, it owns high freedom in motion, high precision and high measurement speed in a wide measurement range.

No MeSH data available.


The standard values of the distances between the points measured by the laser tracker. (a) The measurement of AB, AC and AD; (b) The measurement of AE and AF.
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sensors-15-14328-f005: The standard values of the distances between the points measured by the laser tracker. (a) The measurement of AB, AC and AD; (b) The measurement of AE and AF.

Mentions: The standard should be of considerably higher accuracy than the measurement method being tested. As the laser tracker’s accuracy is higher than that of the combined method, we measure the coordinate of each point many times to calculate the distance between the points and the average of the distances is used as the standard value. For example, as shown in Figure 5a, four nests are glued to a concrete wall in the experiment and the coordinates are created using nests designed to accept a 1.5-inch TBR. At last, the standard values of AB, AC, and AD are obtained. Meanwhile, in Figure 5b, the standard values of AE and AF are also derived in the same manner. All the standard values are listed in Table 1.


Fast Measurement and Reconstruction of Large Workpieces with Freeform Surfaces by Combining Local Scanning and Global Position Data.

Chen Z, Zhang F, Qu X, Liang B - Sensors (Basel) (2015)

The standard values of the distances between the points measured by the laser tracker. (a) The measurement of AB, AC and AD; (b) The measurement of AE and AF.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4507636&req=5

sensors-15-14328-f005: The standard values of the distances between the points measured by the laser tracker. (a) The measurement of AB, AC and AD; (b) The measurement of AE and AF.
Mentions: The standard should be of considerably higher accuracy than the measurement method being tested. As the laser tracker’s accuracy is higher than that of the combined method, we measure the coordinate of each point many times to calculate the distance between the points and the average of the distances is used as the standard value. For example, as shown in Figure 5a, four nests are glued to a concrete wall in the experiment and the coordinates are created using nests designed to accept a 1.5-inch TBR. At last, the standard values of AB, AC, and AD are obtained. Meanwhile, in Figure 5b, the standard values of AE and AF are also derived in the same manner. All the standard values are listed in Table 1.

Bottom Line: With the multi-sensor data fusion, errors accumulated during the image alignment and registration process are minimized, and the measuring precision is significantly improved.The results prove that this new combined method is promising for measuring and reconstructing the large-scale objects with complex surface geometry.Compared with reported methods of large-scale shape measurement, it owns high freedom in motion, high precision and high measurement speed in a wide measurement range.

View Article: PubMed Central - PubMed

Affiliation: State Key Lab of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, China. cz19902013@sina.com.

ABSTRACT
In this paper, we propose a new approach for the measurement and reconstruction of large workpieces with freeform surfaces. The system consists of a handheld laser scanning sensor and a position sensor. The laser scanning sensor is used to acquire the surface and geometry information, and the position sensor is utilized to unify the scanning sensors into a global coordinate system. The measurement process includes data collection, multi-sensor data fusion and surface reconstruction. With the multi-sensor data fusion, errors accumulated during the image alignment and registration process are minimized, and the measuring precision is significantly improved. After the dense accurate acquisition of the three-dimensional (3-D) coordinates, the surface is reconstructed using a commercial software piece, based on the Non-Uniform Rational B-Splines (NURBS) surface. The system has been evaluated, both qualitatively and quantitatively, using reference measurements provided by a commercial laser scanning sensor. The method has been applied for the reconstruction of a large gear rim and the accuracy is up to 0.0963 mm. The results prove that this new combined method is promising for measuring and reconstructing the large-scale objects with complex surface geometry. Compared with reported methods of large-scale shape measurement, it owns high freedom in motion, high precision and high measurement speed in a wide measurement range.

No MeSH data available.