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

Tingting Yan,Heping Zhu,Peter Ling,Xiaochan Wang

doi:10.3390/s18114060

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.

Highlights

IntroductionConventional constant-rate sprayers are often reported to waste much of the spray materials, resulting in increased production costs and environmental contamination potential [2,3,4,5,6]
The timely application of pesticides is critical to protect crops from insect and disease damage [1].conventional constant-rate sprayers are often reported to waste much of the spray materials, resulting in increased production costs and environmental contamination potential [2,3,4,5,6].In order to overcome these problems, modern sprayers are expected to automatically control spray outputs precisely to match the plant configuration and foliage density in order to avoid delivering chemicals to non-target areas
The DRH was significantly affected by the sensor detection heights and horizontal distances

Summary

Introduction

Conventional constant-rate sprayers are often reported to waste much of the spray materials, resulting in increased production costs and environmental contamination potential [2,3,4,5,6]. In order to overcome these problems, modern sprayers are expected to automatically control spray outputs precisely to match the plant configuration and foliage density in order to avoid delivering chemicals to non-target areas. In this way, high efficiency and low production costs can be achieved for pesticide spray applications with minimum environmental impact [7,8,9,10,11,12,13,14]. Chemical application and crop management according to the orchard foliar volume is known as the tree row volume (TRV)

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Conclusion