Academia.eduAcademia.edu

Figure 5 – uploaded by Sylvie Soudarissanane

See full PDFdownloadDownload figure
Fig. 5. Measurement setup of experiment 1. A board placed at a fixed distance of 20 mis scanned at varying incidence angles. A representative laser beam is depicted in red.

Figure 5 Measurement setup of experiment 1. A board placed at a fixed distance of 20 mis scanned at varying incidence angles. A representative laser beam is depicted in red.

Related Figures (18)

Fig. 1. Reflection geometry. Schematic illustration of the reflection geometry, with (left) a perpendicular laser beam (aw = 0), (right) a laser beam with an incidence angle a to the normal N of a planar surface placed at a distance d. P represents the point measured on the surface. The perpendicular laser beam results in a point of range d. The incident beam results in a point of range p. The resulting footprint shape and the energy distribution within the footprint are sketched for both situations.
Fig. 1. Reflection geometry. Schematic illustration of the reflection geometry, with (left) a perpendicular laser beam (aw = 0), (right) a laser beam with an incidence angle a to the normal N of a planar surface placed at a distance d. P represents the point measured on the surface. The perpendicular laser beam results in a point of range d. The incident beam results in a point of range p. The resulting footprint shape and the energy distribution within the footprint are sketched for both situations.
Fig. 3. Effect of increasing incidence angle and range to the signal deterioration. (left) Plot of the signal deterioration due to increasing incidence angle w according to Eq. (15), (right) plot of the signal deterioration due to increasing ranges p according to Eq. (16), with Pmin = 0 mand pmax = 100 m. Fig. 2. Two-way energy budget. In the first way (left), a laser beam with a given beam width is transmitted towards a surface with an incidence angle a, resulting in a footprint on the surface. Depending on the surface reflectivity y, light is scattered in every direction. On the way back (right), the detection unit measures the reflected light within the receiver field of view. In practice, the transmitter and the receiver are located at the same position.
Fig. 3. Effect of increasing incidence angle and range to the signal deterioration. (left) Plot of the signal deterioration due to increasing incidence angle w according to Eq. (15), (right) plot of the signal deterioration due to increasing ranges p according to Eq. (16), with Pmin = 0 mand pmax = 100 m. Fig. 2. Two-way energy budget. In the first way (left), a laser beam with a given beam width is transmitted towards a surface with an incidence angle a, resulting in a footprint on the surface. Depending on the surface reflectivity y, light is scattered in every direction. On the way back (right), the detection unit measures the reflected light within the receiver field of view. In practice, the transmitter and the receiver are located at the same position.
Fig. 4. Reference plate measurement setup. A white coated plywood board is mounted on a tripod via a screw clamp mechanism provided with a 2° precision goniometer.
Fig. 4. Reference plate measurement setup. A white coated plywood board is mounted on a tripod via a screw clamp mechanism provided with a 2° precision goniometer.
Fig. 7. Measurement setup of experiment 2. A board is scanned at varying distances and at varying orientations.
Fig. 7. Measurement setup of experiment 2. A board is scanned at varying distances and at varying orientations.
Fig.6. Standard deviation with respect to the incidence angle of the surface, given a fixed scanner position. The standard deviation of the noise in the direction of the laser beam og, is plotted in red. The orthogonal standard deviation og,, after the removal of the incidence angle effect is plotted in blue.
Fig.6. Standard deviation with respect to the incidence angle of the surface, given a fixed scanner position. The standard deviation of the noise in the direction of the laser beam og, is plotted in red. The orthogonal standard deviation og,, after the removal of the incidence angle effect is plotted in blue.
Fig. 9. Standard deviation with respect to the incidence angle of the surface, given 6 different scanner positions. The standard deviation of the noise in the direction of the laser beam og, is plotted in red. The orthogonal standard deviation o,,, after the removal of the incidence angle effect following Eq. (12), is plotted in blue. Fig. 8. Point clouds of the board colored with intensity. The board is placed at 50 m from the TLS. The presented inclinations are from left to right 0°, 20°, 40° and 60°. The board is outlined in bold lines.
Fig. 9. Standard deviation with respect to the incidence angle of the surface, given 6 different scanner positions. The standard deviation of the noise in the direction of the laser beam og, is plotted in red. The orthogonal standard deviation o,,, after the removal of the incidence angle effect following Eq. (12), is plotted in blue. Fig. 8. Point clouds of the board colored with intensity. The board is placed at 50 m from the TLS. The presented inclinations are from left to right 0°, 20°, 40° and 60°. The board is outlined in bold lines.
Fig. 10. Standard deviation of noise level, given 6 different scanner positions. The standard deviation of the orthogonal noise og, after correction of the incidence angle effect is plotted in blue. The orthogonal standard deviation o¢,, after the removal of the incidence angle effect and the range effect following Eq. (15), is plotted in green. The standard deviation of the 0° case is not plotted due to its particular properties.
Fig. 10. Standard deviation of noise level, given 6 different scanner positions. The standard deviation of the orthogonal noise og, after correction of the incidence angle effect is plotted in blue. The orthogonal standard deviation o¢,, after the removal of the incidence angle effect and the range effect following Eq. (15), is plotted in green. The standard deviation of the 0° case is not plotted due to its particular properties.
Fig. 11. Measurement setup of the standard room measurement using the location of the two view points: viewpoint A at the center and viewpoint B at a corner. (left) 3D representation of the room, with the two viewpoint locations, (right) 2D net-view representation of the room with the two walls and the floor, and the two viewpoint locations.
Fig. 11. Measurement setup of the standard room measurement using the location of the two view points: viewpoint A at the center and viewpoint B at a corner. (left) 3D representation of the room, with the two viewpoint locations, (right) 2D net-view representation of the room with the two walls and the floor, and the two viewpoint locations.
Fig. 12. Net-view representation of the standard room segmentation. The room is segmented into four main segments.
Fig. 12. Net-view representation of the standard room segmentation. The room is segmented into four main segments.
Fig. 15. Net-view of the standard room colored with the noise level €, in the direction of the laser beam. Residuals higher than 1 cm are colored in red. (left) Scan capture from viewpoint A, at the center of the room. (right) Scan captured from viewpoint B, at the corner of the room.
Fig. 15. Net-view of the standard room colored with the noise level €, in the direction of the laser beam. Residuals higher than 1 cm are colored in red. (left) Scan capture from viewpoint A, at the center of the room. (right) Scan captured from viewpoint B, at the corner of the room.
Fig. 13. Net-view of the standard room with spherical patches, using a grid size of 5 x 5°
Fig. 13. Net-view of the standard room with spherical patches, using a grid size of 5 x 5°
Fig. 14. Net-view of the standard room colored with the theoretical incidence angle effects
Fig. 14. Net-view of the standard room colored with the theoretical incidence angle effects
Fig. 16. Net-view of the standard room colored with the noise level ég computed according to Eq. (12). Residuals higher than 1 cm are colored in red. (left) Scan capture from viewpoint A, at the center of the room. (right) Scan captured from viewpoint B, at the corner of the room.
Fig. 16. Net-view of the standard room colored with the noise level ég computed according to Eq. (12). Residuals higher than 1 cm are colored in red. (left) Scan capture from viewpoint A, at the center of the room. (right) Scan captured from viewpoint B, at the corner of the room.
Fig. 17. Net-view of the standard room subdivided into spherical patches of 5° x 5°, colored with the standard deviation og, computed according to Eq. (13). (left) Scan captured from viewpoint A, at the center of the room. (right) Scan captured from viewpoint B, at the corner of the room.
Fig. 17. Net-view of the standard room subdivided into spherical patches of 5° x 5°, colored with the standard deviation og, computed according to Eq. (13). (left) Scan captured from viewpoint A, at the center of the room. (right) Scan captured from viewpoint B, at the corner of the room.
Fig. 18. Net-view of the standard room subdivided into spherical patches of 5° x 5°, colored with the standard deviation og, computed according to Eq. (7). (left) Scar captured from the viewpoint A, at the center of the room. (right) Scan captured from the viewpoint B, at the corner of the room.
Fig. 18. Net-view of the standard room subdivided into spherical patches of 5° x 5°, colored with the standard deviation og, computed according to Eq. (7). (left) Scar captured from the viewpoint A, at the center of the room. (right) Scan captured from the viewpoint B, at the corner of the room.
Related topics:
Geomatic EngineeringPoint CloudNoise MeasurementQuality Measures
580 California St., Suite 400
San Francisco, CA, 94104
© 2025 Academia. All rights reserved