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The dataset contains tree height data collected in 200 mangrove and non-mangrove trees sampled in various sites in Malaysia. Different height measurement methods were performed, including visual measurements (stick, thumb rule) and precision field instruments (clinometer, laser rangefinder and altimeter), which were compared against benchmark values obtained using an unmanned aerial vehicle (UAV) and a Leica distometer. The core data have been analysed and interpreted in the paper by Saliu et al. ‘’An accuracy analysis of mangrove tree height mensuration using forestry techniques, hypsometers and UAVs ’’ [1], in which the accuracy of each method for tree height measurement was discussed.

We performed the first global surface roughness assessment of the asteroid 433 Eros at baselines (horizontal distances) of 4–200 m. We measured surface roughness using the root-mean-square (RMS) deviation over a variety of baselines after first detrending the height to remove long-wavelength slope effects. The global surface roughness of Eros is found to be self-affine at all baselines investigated. The surface roughness is statistically correlated with crater density at baselines of 100–200 m and boulders at a baseline of 5 m. No global spatial statistical correlation was found for baselines of 4–200 and mapped tectonic lineaments, ponds, slope, or geopotential elevation. The surface roughness of the crater Shoemaker (Charlois Regio) is controlled by the interplay of a high boulder density producing higher surface roughness values at small baselines and low crater density lowering surface roughness values at long baselines. We estimated the mobile regolith thickness (regolith that moves around and infills topography) to be 0.2–6.2 m from the difference in the surface roughness values at the baseline of 4 m. Furthermore, we find that the change in RMS deviation as a function of baseline compares favorably with the moon, and differs significantly from existing results for rubble-pile asteroid Itokawa.

Methods for surveying and analyzing channel bed topography commonly lack a rigorous characterization of their appropriateness for project objectives. We compare four survey methods: a hand level, two different methods of surveying with a laser rangefinder, and a real-time kinematic GNSS (RTK-GNSS) to explore their accuracy in determining channel bed slope and roughness for a study reach in a small, dry, steep channel. Additionally, we evaluate the variability among four operators for each survey technique. Two methods of calculating reach slope were computed: a regression on the channel profile and a calculation using only survey endpoints. Using data from the RTK-GNSS as our accuracy reference, the hand level and two-person laser rangefinder surveying systems performed with high accuracy (

An advanced video deflectometer using off-axis digital image correlation is proposed for real-time, non-contact and targetless measurement of vertical deflection of bridges. To achieve real-time displacement tracking with sub-pixel accuracy, an efficient inverse compositional Gauss–Newton algorithm is employed. The detected image displacements in pixels are converted to physical displacements in millimeters using an easy-to-implement yet accurate calibration technique with the aid of a laser rangefinder. Real translation tests with precisely controlled motions were performed to examine the accuracy of the proposed technique. Real-time deflection monitoring of a railway bridge subjected to train pass-by is also demonstrated to show the practicality, accuracy and application potential of the proposed technique.

Laser may cause disfunction or even damage to laser rangefinder. Based on evaluation rules of high repetition rate laser jam pulsed laser rangefinder, the principles of distance deception and blinding jamming were analysed and the jamming success rate was calculated. We also set up a calculation example for 100 kHz repetition rate laser jam certain type rangefinder. The result showed that we can obtain jamming grade and success rate, accomplish the quantitative evaluation of the laser jamming effect.

In this paper, an external parameter calibration method for multiple cameras with non-overlapping fields of view (FOVs) using a laser rangefinder (LRF) is presented. The proposed method combines multiple cameras by the laser beam projected by the LRF. The main procedures of the proposed method are: The LRF is positioned for a few (at least two) times and projects a laser beam across the FOVs of different cameras. The laser beam is intercepted by a planar object for at least 3 times in the FOV of each camera. The cameras capture the laser spots projected on the planar object and the LRF measures the distances between the different spots. According to the co-linearity of the laser spots captured by all the cameras at each LRF position and the distances between the laser spots, the external parameters between different cameras can be computed. If the laser beam cannot reach the FOVs of all the cameras, the calibration of all the cameras can be achieved by pair-wise calibration. Experiment results show that the relative point pair distance error is around 0.3‰ when the distance between the two cameras is around four meters.

Monocular camera based laser rangefinder is an economical strategy for retrieving the distance data. It is released from a burden of buying the expensive laser scanning sensor. In this paper, we proposed an improved framework for application on the mobile robots. This framework addressed the disadvantages in the original design. We chose the carpentry board instead of the cardboard to enhance the mechanical strength, and applied the curve fitting technology to compensate for the distance computational error induced by the lens distortion. Experiments on the mobile robots evaluated the performance of the proposed sensor framework. The results show that the improved mechanical structure can avoid the motion vibration of the mobile robot and curve fitting method can decrease the computational error especially for the case that the distance between sensor and object is much larger.

This paper discussed an information sharing system for multiple mobile robots using IC tags. In our system, the multiple mobile robots share the environmental information using IC tags. It is necessary for intelligent mobile robot to recognize the environmental information around the robot. The IC tag is very useful device for getting the environmental information around the robot. We developed the mobile robot which is equipped an IC tag reader/writer with an antenna, a laser rangefinder and a PC. We use the laser rangefinder in order to detect the collision-free space around the robot. The mobile robots write and read the information to the IC tag and share the environmental information each other. This mobile robot moves according to the information from the IC tags. The effectiveness of our system is demonstrated by several experimental results.

We developed a remote control system for maintenance of in-cell type fuel fabrication equipment. The system display recreated three-dimensional information of the workspace from data obtained by laser rangefinder and conventional cameras. It has allowed us to operate a manipulator arm remotely with several control modes. In order to evaluate the effectiveness and usefulness of developed system, we implemented remote handling experiments using mock up equipment. Performance was compared for remote operation conducted using several different display and operation modes. We confirmed that the system is able to maintain in-cell fuel fabrication equipment in each display and operation mode. Times required to complete the remote operations were collected and compared in each mode. It was observed that integration of 3D information from the laser rangefinder reduced operation time and reinforced visual information during remote operation.

The possibility of early fire detection via lidar (light detection and ranging) technology implemented through a low-cost rangefinder is investigated. The evaluation is based on the variation of signal-to-noise ratio (SNR) with distance calculated on the basis of a theoretical model and determined experimentally. The theoretical SNR is obtained by combining a hydrodynamic model of the smoke plume taking into consideration the effect of wind (which enables calculation of smoke–particle distribution) and a lidar model that enables backscattered radiation intensity, detected power and, eventually, SNR to be assessed using Mie theory. The calculated values of SNR agree reasonably well with the experimental results obtained using small-scale experimental fires and show that in favourable conditions detection ranges up to about 4 km are achievable.

This paper presents a map building method of an autonomous mobile robot's environment. It is based on an original « focus of attention » cooperation system using a laser rangefinder as the main source of information and a video camera mounted on a pantilt unit to perform close inspection of selected objects in the scene; selection of such objects being performed by analysing data from the laser rangefinder. This cooperation process provides a sufficiently rich description of the robot's environment to call for more complex tasks such as localisation.

In 1999, the Near Earth Asteroid Rendezvous (NEAR) mission will place a spacecraft with five facility instruments, including the NEAR Laser Rangefinder (NLR), into a low-altitude (~50 km) orbit about the asteroid 433 Eros. The NLR is a high-fidelity altimeter capable of 31.5-cm resolution and

We propose an approach for representing an object by its constituent parts and their spatial connections based on a set of primitive volumes called geons previously introduced by Biederman. We utilize the edge-junction graph of an object range image as input then decompose this graph into different subgraphs which correspond to the constituent parts of the object. For each part, edge characteristics guide us to an inference regarding the corresponding geon shape. Also, the spatial connections among these parts can be deduced from the concave edges andT-junctions. Several experimental results with a laser rangefinder are presented.

This paper deals with the application of computer vision to mining automation. In particular, it presents results from an on-going research project investigating the automation of the rock-breaking process, a process typical of underground hardrock mining. The objective of this research is to investigate the use of computer vision to identify and locate the oversized lumps remaining on a grizzly (metal sieve) after blasting, for the secondary rock-breaking operation. Range images of rocks are acquired in our laboratory using the NRCC/McGill laser rangefinder. Rock-pile images are segmented into parts (rocks) based on their surface characteristics. Finally, superquadric models are fit to the segmented range data to characterize the 3D shape of each rock.

Two sensors have been developed for autonomous rendezvous and docking manoeuvres in space in the range up to 100 m. The first is a proximity sensor, which is dedicated for distance and angle measurements. The sensor's equipment consists of three units: the position-sensitive detector, the illuminator and the common optics including a c.w. laser rangefinder. On the target side a corresponding reflector complements the necessary equipment to measure distance and angle deviation from boresight direction. The measured resolution of the sensor for a distance of 2 m is