Evaluation of Object Surface Edge Profiles Detected with a 2-D Laser Scanning Sensor

Abstract

Canopy edge profile detection is a critical component of plant recognition in variable-rate spray control systems. The accuracy of a high-speed 270° radial laser sensor was evaluated in detecting the surface edge profiles of six complex-shaped objects. These objects were toy balls with a pink smooth surface, light brown rectangular cardboard boxes, black and red texture surfaced basketballs, white smooth cylinders, and two different sized artificial plants. Evaluations included reconstructed three-dimensional (3-D) images for the object surfaces with the data acquired from the laser sensor at four different detection heights (0.25, 0.50, 0.75, and 1.00 m) above each object, five sensor travel speeds (1.6, 2.4, 3.2, 4.0, and 4.8 km h−1), and 8 to 15 horizontal distances to the sensor ranging from 0 to 3.5 m. Edge profiles of the six objects detected with the laser sensor were compared with images taken with a digital camera. The edge similarity score (ESS) was significantly affected by the horizontal distances of the objects, and the influence became weaker when the objects were placed closer to each other. The detection heights and travel speeds also influenced the ESS slightly. The overall average ESS ranged from 0.38 to 0.95 for all the objects under all the test conditions, thereby providing baseline information for the integration of the laser sensor into future development of greenhouse variable-rate spray systems to improve pesticide, irrigation, and nutrition application efficiencies through watering booms.

Special Issue on “Terrestrial Laser Scanning”: Editors’ Notes

“…An object’s edge detection is of particular interest in many practical situations, such as the characterization of plants and small objects, and has specific difficulties to be faced. For instance, in [2], the accuracy of a laser sensor in detecting the surface edge profiles of six different colored and textured complex-shaped objects including toy balls, rectangular cardboard boxes, basketballs, cylinders, and two different sized artificial plants, was evaluated. Three-dimensional images for each object’s surface at different LiDAR detection heights, travel speeds and horizontal distances were reconstructed.…”

The development and application of an original 3D laser scanning: a precise and nondestructive structural measurements system

“…It generally requires multiple devices to work together to obtain spatial deformation information [8]. And the 3D laser scanning measuring device has the following advantages: 1) non-destructive: getting rid of installing the sensor on the object to be detected; 2) strong environmental adaptability: the laser itself can be used as a light source to resist interference; 3) efficient detection: can achieve 3D information acquisition of a single device [9][10][11][12]. Therefore, the 3D laser scanning technology have lately received great attention in the field of building structure inspection [13,14].…”