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

Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 4060 ◽  
Author(s):  
Tingting Yan ◽  
Xiaochan Wang ◽  
Heping Zhu ◽  
Peter Ling
Keyword(s):  
High Speed ◽  
Laser Scanning ◽  
Three Dimensional ◽  
Digital Camera ◽  
Similarity Score ◽  
Laser Sensor ◽  
Variable Rate ◽  
Edge Profile ◽  
Baseline Information ◽  
Edge Similarity

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.

Investigation of an Experimental Laser Sensor-Guided Spray Control System for Greenhouse Variable-Rate Applications

2019 ◽  
Vol 62 (4) ◽  
pp. 899-911
Author(s):  
Tingting Yan ◽  
Heping Zhu ◽  
Li Sun ◽  
Xiaochan Wang ◽  
Peter Ling
Keyword(s):  
Control System ◽  
Delay Time ◽  
High Speed ◽  
Laser Scanning ◽  
Plant Production ◽  
Laser Sensor ◽  
Variable Rate ◽  
Spray Volume ◽  
Spray Control ◽  
Variable Rate Spraying

Abstract. Precision variable-rate spraying technology is needed for controlled-environment plant production in greenhouses. An experimental spray system for greenhouse applications was developed for real-time control of individual nozzle outputs. The system mainly consisted of a high-speed laser scanning sensor, 12 individual variable-rate nozzles, an embedded computer, a spray control unit, and a 3.6 m long mobile spray boom. Each nozzle was coupled with a pulse-width modulated solenoid valve to discharge sprays at variable rates based on target presence and plant canopy structure. Laboratory tests were conducted to evaluate the accuracy of the spray control system in respect to spray delay time, nozzle activation, and spray volume using four target objects of different regular geometrical shapes and surface textures and two artificial plants of different canopy structures. Other experimental variables included three detection heights from 0.5 to 1.0 m and five sensor travel speeds from 1.6 to 4.8 km h-1. A high-speed video camera was used to determine the delay time and nozzle activation in discharging sprays on target objects after the laser sensor had detected the objects. The detection height and travel speed were found to have slight influence on the timing of nozzle activation. The nozzles started spraying in a range between 33 and 83 mm before reaching the target objects and stopped spraying between 13 and 84 mm after passing the objects, ensuring that the objects were fully covered by the spray. Spray volume corresponded to the object sizes well, and the spray control system performed with higher accuracy at lower travel speeds. Differences between the calculated spray volume based on the sensor detection and the actual spray volume ranged from 1.9 to 2.7 mL per object among all tested objects. The variable-rate control system reduced spray volume by 29.3% to 51.4% for all the objects compared with conventional constant-rate spraying. At the same time, the nozzles could be activated precisely by the object presence. Consequently, this experimental laser-guided system was implemented on a boom system in a commercial greenhouse for future investigations of its accuracy in variable-rate spraying to save pesticides, water, and nutrients. Keywords: Automation, Intelligent sprayer, Pesticide, Precision spray technology, Boom spray equipment.

scholarly journals High-speed volumetric two-photon fluorescence imaging of neurovascular dynamics

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Jiang Lan Fan ◽  
Jose A. Rivera ◽  
Wei Sun ◽  
John Peterson ◽  
Henry Haeberle ◽  
...  
Keyword(s):  
Blood Flow ◽  
High Speed ◽  
Laser Scanning ◽  
Three Dimensional ◽  
Laser Scanning Microscopy ◽  
Fluorescence Signal ◽  
Imaging Method ◽  
Spatiotemporal Resolution ◽  
Two Photon

AbstractUnderstanding the structure and function of vasculature in the brain requires us to monitor distributed hemodynamics at high spatial and temporal resolution in three-dimensional (3D) volumes in vivo. Currently, a volumetric vasculature imaging method with sub-capillary spatial resolution and blood flow-resolving speed is lacking. Here, using two-photon laser scanning microscopy (TPLSM) with an axially extended Bessel focus, we capture volumetric hemodynamics in the awake mouse brain at a spatiotemporal resolution sufficient for measuring capillary size and blood flow. With Bessel TPLSM, the fluorescence signal of a vessel becomes proportional to its size, which enables convenient intensity-based analysis of vessel dilation and constriction dynamics in large volumes. We observe entrainment of vasodilation and vasoconstriction with pupil diameter and measure 3D blood flow at 99 volumes/second. Demonstrating high-throughput monitoring of hemodynamics in the awake brain, we expect Bessel TPLSM to make broad impacts on neurovasculature research.

scholarly journals INTEGRATION OF GEODATA IN DOCUMENTING CASTLE RUINS

2016 ◽  
Vol XLI-B3 ◽  
pp. 345-349
Author(s):  
P. Delis ◽  
M. Wojtkowska ◽  
P. Nerc ◽  
I. Ewiak ◽  
A. Lada
Keyword(s):  
Laser Scanning ◽  
Three Dimensional ◽  
Digital Camera ◽  
Terrestrial Laser Scanning ◽  
Point Clouds ◽  
3D Models ◽  
Digital Imagery ◽  
Historical Structures ◽  
Three Dimensional Models ◽  
Different Sources

Textured three dimensional models are currently the one of the standard methods of representing the results of photogrammetric works. A realistic 3D model combines the geometrical relations between the structure’s elements with realistic textures of each of its elements. Data used to create 3D models of structures can be derived from many different sources. The most commonly used tool for documentation purposes, is a digital camera and nowadays terrestrial laser scanning (TLS). Integration of data acquired from different sources allows modelling and visualization of 3D models historical structures. Additional aspect of data integration is possibility of complementing of missing points for example in point clouds. The paper shows the possibility of integrating data from terrestrial laser scanning with digital imagery and an analysis of the accuracy of the presented methods. The paper describes results obtained from raw data consisting of a point cloud measured using terrestrial laser scanning acquired from a Leica ScanStation2 and digital imagery taken using a Kodak DCS Pro 14N camera. The studied structure is the ruins of the Ilza castle in Poland.

High-speed three-dimensional laser sensor

2000 ◽  
Author(s):  
Liviu Bursanescu ◽  
Mihaela Bursanescu ◽  
Maher Hamdi ◽  
Francois Blais ◽  
David A. Green
Keyword(s):  
High Speed ◽  
Three Dimensional ◽  
Laser Sensor

scholarly journals CREATION OF A THREE-DIMENSIONAL MODEL OF ARCHITECTURAL STRUCTURE IN AGISOFT PHOTOSCAN

2020 ◽  
Vol 6 (1) ◽  
pp. 161-166
Author(s):  
Egor V. Kazharin
Keyword(s):  
Laser Scanning ◽  
Three Dimensional ◽  
Digital Camera ◽  
Object Model ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Architectural Structures ◽  
Three Dimensional Models ◽  
Time Required ◽  
The Cost

All architectural structures are a subject to periodic surveys and use of photogrammetric methods for these purposes will ensure a reduction in time required to complete the work, required accuracy, as well as ability to fulfill the required measurements on a pair of images in office conditions without additional field visits, which will significantly reduce the cost of implementation of this type of work. In order to solve the problems of building three-dimensional models of such objects, a ground-based photography is used more often. This method of photographing, in comparison with other methods, such as ground-based laser scanning, facade shooting with the help of electronic total stations, seems more affordable, since it does not require the use of expensive equipment, but it makes it possible to build an object model with the specified accuracy. For ground photography it is enough to have a calibrated digital camera, computer and software. The purpose of this work is to study the method of constructing a three-dimensional model of an architectural structure based on photogrammetric processing of images, as well as optimizing the result and demonstrating the operability of the method.

scholarly journals THREE-DIMENSIONAL MAPPING OF AN ANCIENT CAVE PAINTINGS USING CLOSE-RANGE PHOTOGRAMMETRY AND TERRESTRIAL LASER SCANNING TECHNOLOGIES

2017 ◽  
Vol XLII-2/W3 ◽  
pp. 453-457 ◽  
Author(s):  
Z. Majid ◽  
M. F. M. Ariff ◽  
K. M. Idris ◽  
A. R. Yusoff ◽  
K. M. Idris ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Three Dimensional ◽  
Digital Camera ◽  
Terrestrial Laser Scanning ◽  
Point Clouds ◽  
Innovative Technology ◽  
Close Range Photogrammetry ◽  
Digital Format ◽  
Cave Paintings ◽  
Close Range

The paper describes the used of close-range photogrammetry and terrestrial laser scanning technologies as an innovative technology for acquiring the three-dimensional data of an ancient cave paintings. The close-range photogrammetry technology used in the research was divided in two categories which are the UAV-based close-range photogrammetry and the terrestrialbased close-range photogrammetry. The UAV-based technology involved with the used of calibrated Phantom 4 System while the terrestrial-based technology involved with the calibrated Sony F828 digital camera and pPhotoModeler software. Both stereo and convergent image acquisition techniques were used to acquire the images of the paintings. The ancient cave paintings were also recorded using terrestrial laser scanning technology. In the research, the FARO Focus 3D terrestrial laser scanner was used to capture the three-dimensional point clouds and images of the paintings. The finding shows that both close-range photogrammetry and laser scanning technologies provide excellent solutions to map and to record the ancient paintings. As compared to the conventional method, both close-range photogrammetry and terrestrial laser scanning technology provide a noncontact solution for data acquisition and the data was recorded in digital format for better protection and security.

scholarly journals Evaluation of Maraging Steel Produced Using Hybrid Additive/Subtractive Manufacturing

2021 ◽  
Vol 5 (4) ◽  
pp. 107
Author(s):  
Sheida Sarafan ◽  
Priti Wanjara ◽  
Javad Gholipour ◽  
Fabrice Bernier ◽  
Mahmoud Osman ◽  
...  
Keyword(s):  
Relative Density ◽  
Maraging Steel ◽  
Computer Aided Design ◽  
High Speed ◽  
Laser Scanning ◽  
Three Dimensional ◽  
Hybrid Manufacturing ◽  
Micro Computed Tomography ◽  
Subtractive Manufacturing ◽  
Static Tensile

Hybrid manufacturing is often used to describe a combination of additive and subtractive processes in the same build envelope. In this research study, hybrid manufacturing of 18Ni-300 maraging steel was investigated using a Matsuura LUMEX Avance-25 system that integrates metal additive manufacturing using laser powder bed fusion (LPBF) processing with high-speed machining. A series of benchmarking coupons were additively printed at four different power levels (160 W, 240 W, 320 W, 380 W) and with the integration of sequential machining passes after every 10 deposited layers, as well as final finishing of selected surfaces. Using non-contact three-dimensional laser scanning, inspection of the final geometry of the 18Ni-300 maraging steel coupons against the computer-aided design (CAD) model indicated the good capability of the Matsuura LUMEX Avance-25 system for net-shape manufacturing. Linear and areal roughness measurements of the surfaces showed average Ra/Sa values of 8.02–14.64 µm for the as-printed walls versus 0.32–0.80 µm for the machined walls/faces. Using Archimedes and helium (He) gas pycnometry methods, the part density was measured to be lowest for coupons produced at 160 W (relative density of 93.3–98.5%) relative to those at high power levels of 240 W to 380 W (relative density of 99.0–99.8%). This finding agreed well with the results of the porosity size distribution determined through X-ray micro-computed tomography (µCT). Evaluation of the static tensile properties indicated that the coupons manufactured at the lowest power of 160 W were ~30% lower in strength, 24% lower in stiffness, and more than 80% lower in ductility relative to higher power conditions (240 W to 380 W) due to the lower density at 160 W.

scholarly journals Application of laser scanning for monitoring condition of buildings and structures during reconstruction

2021 ◽  
pp. 33-36
Author(s):  
Irina Rudneva
Keyword(s):  
High Speed ◽  
Laser Scanning ◽  
New Technology ◽  
Three Dimensional ◽  
Return Time ◽  
Measurement Methods ◽  
Laser Beams ◽  
Operational Control ◽  
Labor Costs ◽  
Engineering Geodesy

Ground-based laser scanning technology has been increasingly used in the last 15 years to solve problems not only in engineering geodesy, but also in the inspection of buildings and structures, in particular to identify damage and deformation during operation and reconstruction, as well as operational control of construction. and monitoring of their condition during operation, 3D-modeling of complex architectural objects. The growing popularity of laser scanning is due to a number of advantages provided by the new technology in comparison with other measurement methods. Among the advantages are the main ones: increasing the speed of work and reducing labor costs. The emergence of new more productive models of scanners, improving software capabilities allows us to hope for further expansion of the scope of ground-based laser scanning. Three-dimensional laser scanning emits millions of laser beams and, by calculating their return time, can accurately and accurately calculate their three-dimensional locations to make multiple high-speed scans combined into one system. This works by digitally recording the dimensions and spatial communication of objects by reflecting laser radiation.

scholarly journals INTEGRATION OF GEODATA IN DOCUMENTING CASTLE RUINS

2016 ◽  
Vol XLI-B3 ◽  
pp. 345-349 ◽  
Author(s):  
P. Delis ◽  
M. Wojtkowska ◽  
P. Nerc ◽  
I. Ewiak ◽  
A. Lada
Keyword(s):  
Laser Scanning ◽  
Three Dimensional ◽  
Digital Camera ◽  
Terrestrial Laser Scanning ◽  
Point Clouds ◽  
3D Models ◽  
Digital Imagery ◽  
Historical Structures ◽  
Three Dimensional Models ◽  
Different Sources

Textured three dimensional models are currently the one of the standard methods of representing the results of photogrammetric works. A realistic 3D model combines the geometrical relations between the structure’s elements with realistic textures of each of its elements. Data used to create 3D models of structures can be derived from many different sources. The most commonly used tool for documentation purposes, is a digital camera and nowadays terrestrial laser scanning (TLS). Integration of data acquired from different sources allows modelling and visualization of 3D models historical structures. Additional aspect of data integration is possibility of complementing of missing points for example in point clouds. The paper shows the possibility of integrating data from terrestrial laser scanning with digital imagery and an analysis of the accuracy of the presented methods. The paper describes results obtained from raw data consisting of a point cloud measured using terrestrial laser scanning acquired from a Leica ScanStation2 and digital imagery taken using a Kodak DCS Pro 14N camera. The studied structure is the ruins of the Ilza castle in Poland.

scholarly journals A DATA DRIVEN METHOD FOR BUILDING RECONSTRUCTION FROM LiDAR POINT CLOUDS

2014 ◽  
Vol XL-2/W3 ◽  
pp. 225-230 ◽  
Author(s):  
M. Sajadian ◽  
H. Arefi
Keyword(s):  
High Speed ◽  
Laser Scanning ◽  
Pulse Length ◽  
Three Dimensional ◽  
Point Clouds ◽  
Building Model ◽  
Building Models ◽  
Edge Points ◽  
Normal Vectors ◽  
Building Reconstruction

Airborne laser scanning, commonly referred to as LiDAR, is a superior technology for three-dimensional data acquisition from Earth's surface with high speed and density. Building reconstruction is one of the main applications of LiDAR system which is considered in this study. For a 3D reconstruction of the buildings, the buildings points should be first separated from the other points such as; ground and vegetation. In this paper, a multi-agent strategy has been proposed for simultaneous extraction and segmentation of buildings from LiDAR point clouds. Height values, number of returned pulse, length of triangles, direction of normal vectors, and area are five criteria which have been utilized in this step. Next, the building edge points are detected using a new method named "Grid Erosion". A RANSAC based technique has been employed for edge line extraction. Regularization constraints are performed to achieve the final lines. Finally, by modelling of the roofs and walls, 3D building model is reconstructed. The results indicate that the proposed method could successfully extract the building from LiDAR data and generate the building models automatically. A qualitative and quantitative assessment of the proposed method is then provided.

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