Laser Profile Data Research Articles

Automatic Groove Measurement and Evaluation with High Resolution Laser Profiling Data

Grooving is widely used to improve airport runway pavement skid resistance during wet weather. However, runway grooves deteriorate over time due to the combined effects of traffic loading, climate, and weather, which brings about a potential safety risk at the time of the aircraft takeoff and landing. Accordingly, periodic measurement and evaluation of groove performance are critical for runways to maintain adequate skid resistance. Nevertheless, such evaluation is difficult to implement due to the lack of sufficient technologies to identify shallow or worn grooves and slab joints. This paper proposes a new strategy to automatically identify airport runway grooves and slab joints using high resolution laser profiling data. First, K-means clustering based filter and moving window traversal algorithm are developed to locate the deepest point of the potential dips (including noises, true grooves, and slab joints). Subsequently the improved moving average filter and traversal algorithms are used to determine the left and right endpoint positions of each identified dip. Finally, the modified heuristic method is used to separate out slab joints from the identified dips, and then the polynomial support vector machine is introduced to distinguish out noises from the candidate grooves (including noises and true grooves), so that PCC slab-based runway safety evaluation can be performed. The performance of the proposed strategy is compared with that of the other two methods, and findings indicate that the new method is more powerful in runway groove and joint identification, with the F-measure score of 0.98. This study would be beneficial in airport runway groove safety evaluation and the subsequent maintenance and rehabilitation of airport runway.

Case study of debris flow disaster scenario caused by torrential rain on Kiyomizu-dera, Kyoto, Japan - using Hyper KANAKO system

This paper presents debris-flow numerical simulations using the Hyper KANAKO system, developed by the authors. The system uses the debris flow simulator KANAKO 2D equipped with a graphical user interface (GUI); hence, a user can easily produce appropriate landform data for simulations using standard laser profiler data, and visualize the results using a GIS. Hyper KANAKO was applied to the streams around Kiyomizu-dera in Kyoto, Japan. Kiyomizu-dera is a famous temple in Japan which is visited by numerous tourists throughout the year. We simulated a disaster scenario of debris flow caused by torrential rain. We set the hydrograph using rainfall intensity data, and set the landform data using information from the Geospatial Information Authority of Japan (GSI) and a digital elevation model (DEM). We evaluated different mesh sizes and also used a digital surface model (DSM) to consider the building heights. The simulation results showed that with small mesh size, the debris flow moved through the roads, which seems realistic for a disaster situation. When buildings were considered, the flow direction changed, and a 1-m flow depth, which was deeper than in other cases, appeared in the flow path. This may pose a dangerous situation for evacuations.

LP データと河川定期縦横断測量成果を用いた任意地点の横断図生成手法に関する研究

LP データと河川定期縦横断測量成果を用いた任意地点の横断図生成手法に関する研究

LPデータを活用した土石流シミュレーションシステム「Hyper KANAKO」の開発

LPデータを活用した土石流シミュレーションシステム「Hyper KANAKO」の開発

大腸菌群数と土地利用の相関分析

We analyze and evaluate a correlation of total coliform and land use data on a monthly basis in the downstream of Oita River. In addition,we analyze and evaluate the optimal range to use laser profiler data from the total coliform's observation points. As a result of the analysis, we found that the correlation of building land is high in land use, and the correlation of total coliform of March and June is high in the case of using land use data of about 2.0 km radius.

Numerical Simulations of Flood and Inundation in Jobaru River Basin Using Laser Profiler Data

Numerical Simulations of Flood and Inundation in Jobaru River Basin Using Laser Profiler Data

大腸菌群数とレーザプロファイラデータのエントロピーの相関分析

大腸菌群数とレーザプロファイラデータのエントロピーの相関分析

Best ellipse and cylinder parameters estimation from laser profile scan sections

Industrial applications like robot-aided welding, automated inspection, and 3D measurements require 3D points to be captured from the surfaces of objects and processed to calculate the information-of-interest. The lack of research focused on fitting ellipses to 3D laser profile data, and the intrinsic features that distinguish it from 2D digital images, motivated us to conduct a comparative study involving the most popular ellipse-fitting methods. After describing our laser profile scanning system, and a survey of ellipse-fitting methods, we compare, using extensive experiments performed with synthetic and real data, the fitting algorithms in terms of stability and accuracy with respect to a variety of factors. The estimate obtained with the best method is used to initialize a robust non-linear iterative ellipse fitting method. Finally, we describe a novel method for the construction of cylindrical surfaces from estimated elliptical sections.

A simple spectro-goniometer for collection of multiple view angle reflectance factors

Field spectroradiometers are widely used for environmental applications where data describing visible and near-infrared reflectance factors are of interest. Recent developments in spaceborne and airborne instruments with multiple view angle (MVA) capabilities have resulted in a demand for ground measurements to support these missions. Lightweight portable spectroradiometers offer an appropriate means of collecting MVA spectral reflectance factor data because they are more easily manoeuvrable than other spectroradiometers, but their physical capabilities have not yet been explored in this context. This letter presents the results of a focused experiment aimed at evaluating the field capabilities of a miniaturized Ocean Optics instrument in MVA settings for soil surface roughness applications. MVA hemispherical-conical reflectance factors were collected in situ from soil surfaces whose roughness was determined using a laser profiling survey. The results showed a significant negative relationship (R 2 = 0.74; p < 0.01) between directional reflectance factors measured at 870 nm in the forward-scattering region and a soil structural measure derived from laser profiling data. This corroborates the results of other published studies and suggests that Ocean Optics instruments can be used to support hyperspectral MVA investigations.

Design and Application of 3D Laser Profile Data Acquisition System

AbstractIn order to measure the trivial road deformation by the full—scale accelerated load testing, a theory to acquire 3D laser profile data with a single—point laser (2 μm) was proposed to design and develop a measuring instrument. The design and realization of the overall structure and software were discussed in detail. Moreover, the acquisition of 3D laser profile data and the method of graphic reconstruction as well as the measurement error of the instrument were investigated. Thus, 3D information of road surface was obtained by using this measuring instrument with an accuracy of ±0.5 mm. The result indicates that the road indexes such as rut, structural depth and potholes can be acquired through this 3D laser profile data acquisition system with high efficiency and accuracy.

CONSTRUCTION OF URBAN INUNDATION MODEL BASED ON INTEGRATED DIGITAL DATA

In this study, taking up the area which is not put up city block data, calculation technique to calculate city block is developed according to combining digital map 2500 with city region digital map in Sendai City. Besides in these years digital sewage map is computerized in various regions. And so we can obtain from digital sewerage map the information, and the technique which can connect to the road network on the ground was developed. Furthermore the method to divide into pervious area and impervious area which has an effect on the landside inundation with laser profiler data is developed. Based on the above result, analytical model is applied to rainfall of August, 1986, and the result set against the questionnaire result.

Locating and estimating the extent of Delmarva fox squirrel habitat using an airborne LiDAR profiler

Two thousand five hundred thirty-nine kilometers of airborne laser profiling and videography data were acquired over the state of Delaware during the summer of 2000. The laser ranging measurements and video from approximately one-half of that data set (1304 km) were analyzed to identify and locate forested sites that might potentially support populations of Delmarva fox squirrel (DFS, Sciurus niger cinereus). The DFS is an endangered species previously endemic to tall, dense, mature forests with open understories on the Eastern Shore of the Chesapeake Bay. The airborne LiDAR employed in this study can measure forest canopy height and canopy closure, but cannot measure or infer understory canopy conditions. This airborne LiDAR profiler, then, must be viewed as a tool that identifies and locates potential, not actual, habitat. Fifty-three potentially suitable DFS sites were identified in the 1304 km of flight transect data. Each of the 53 sites met the following criteria according to the LiDAR and video record: (1) at least 120 m of contiguous forest; (2) an average canopy height >20 m; (3) an average canopy closure of > 80%; and (4) no roofs, impervious surface (e.g., asphalt, concrete), and/or open water anywhere along the 120 m length of the laser segment. Thirty-two of the 53 sites were visited on the ground and measurements taken for a DFS habitat suitability model. Seventy-eight percent of the sites (25 of 32) were judged by the model to be suited to supporting a DFS population. All of the LiDAR flight data, 2539 km, were analyzed to estimate county and statewide forest area in different height/canopy closure classes. Approximately 3.3% of Delaware (17,137 ha) supports forest over 20 m tall with crown closures exceeding 80%; the corresponding county percentages are Newcastle County—6.1% (6823 ha), Kent County—2.2% (3431 ha), and Sussex County—2.7% (6883 ha). Estimates of average within-patch crossing distance and average between-patch distances are reported, by county, and for the state. Study results indicate that: 1) systematic airborne LiDAR data can be used to screen extensive areas to locate potential DFS habitat; 2) 78% of sites meeting certain minimum length, height, and canopy closure criteria will support DFS populations, according to a habitat suitability model; 3) airborne LiDAR can be used to calculate county and state acreage estimates of potential habitat, and 4) the linear transect data can be used to calculate patch statistics. The authors suggest that the systematic county and state flight lines can be revisited at intervals to monitor changes to the areal extent of potential habitat over time.

Measuring biomass and carbon in delaware using an airborne profiling LIDAR

A portable, inexpensive profiling light detection and ranging (LIDAR) system was used to inventory forests in Delaware, a small state (5205 km2) on the mid-Atlantic seaboard of the USA. Ground and airborne sampling procedures are described, and large-area inventory results are reported and compared to independent estimates. Systematic airborne LIDAR profiling measurements were used (1) to estimate forest merchantable volume, biomass and above-ground carbon statewide; and (2) to estimate impervious surface and open water area. Over 1300 km of laser profiling data acquired along parallel flight lines 4 km apart were analysed. Four explicitly linear models were considered to predict merchantable volume and total above-ground dry biomass. Merchantable volume estimates were within 21% of US Forest Service estimates at the county level and within 1% statewide. Total above-ground dry biomass estimates were within 22% of USFS estimates at the county level and within 16% statewide. LIDAR estimates of percentage impervious area surface for the three counties (Newcastle, Kent and Sussex) were 10.9, 3.4 and 2.8%, respectively, and 4.7% statewide. Comparable estimates developed using 30 m Enhanced Thematic Mapper digital data and mixture modelling were 8.8, 3.5 and 3.9%, respectively, and 4.9% statewide. Laser estimates of open water at the county and state level were comparable to 1997 Geographical Information System (GIS) estimates. Open water estimates based on laser transect data showed the three counties to have 3.0, 2.0 and 4.6% of their county area covered by water, and 3.5% of the state to be covered by open water. Comparable 1997 GIS estimates were 2.6, 2.1 and 4.8% (county), and 3.5% (state), respectively. The results of the study indicate that line intercept sampling techniques can be used in conjunction with a relatively inexpensive, portable airborne laser system to assess multiple resources regionally.

Assessment and monitoring of foliage projected cover and canopy height across native vegetation in Queensland, Australia, using laser profiler data

The aim of this project was to demonstrate the potential of laser profiling for monitoring forest structure. Data were captured from flights at 30, 60, and 100 m above the canopy over three study sites in south-east Queensland at regular intervals over a 2-year period. Field measurements of foliage projected cover (FPC) and tree height were found to be highly correlated with laser derived estimates (R2 from 0.91 to 0.95). Monitoring of changes in FPC and tree height, as a result of logging or growth, was also successful. Tree heights, in particular, were measured accurately over time (residual standard error (RSE) of 0.45 m). The large RSE of the FPC model (from 5.7% to 7.3% FPC) means that subtle changes, such as seasonal variation, may be difficult to monitor. Flying height was found to be a significant explanatory variable in estimating field FPC. A transect of greater than 1000 km was also flown in a single helicopter pass to assess the technology over a range of forest types. Field measurements of FPC were collected for 21 sites along this transect. Strong relationships were observed between laser and field FPC, but these varied with forest type.

Fractal scaling of surface roughness in artificially weathered smectite-rich soil regoliths

Laboratory trials were established to simulate, under controlled conditions, the natural weathering sequence of smectite-rich soil regoliths from a highly degraded badland area at Vallcebre, Eastern Pyrenees Range (Spain). Experiments were carried out to deepen the knowledge on the response of the bulk materials to experimental freezing–thawing and wetting–drying cycles, and the role of the mineral components in the path of surface structure detachment. During the experiments, variation of surface roughness was determined by measuring consecutive transects of the artificially weathered samples with a noncontact laser profile meter and data were analysed with a program written for this purpose. The analysis of data was based on the calculation of the fractal dimension, according to the Richardson equation, of sequential surface profiles of samples in frozen, thawed, wetted and dried conditions in order to achieve a dynamic description of surface aggregate shape arrangement along the whole sequence and at different scale ranges. The Hurst exponent of selected bulk data was also calculated in order to find added evidence of the nature of surface, which, in some cases, appeared to be multifractal with the Richardson diagram. The fractal model applied allowed to obtain fractal dimension values of surface roughness which were used to explain how the pedological characteristics of a given material containing clay and carbonate association may react to applied climatic extremes, thereby showing differential surface arrangement and weathering paths. Freezing and thawing as well as wetting and drying events modified the sample's surface, and these effects describe the material susceptibility to weathering against individual climatic components and may be useful in erosion modelling at the catchment scale.

A Multiple Resource Inventory of Delaware Using Airborne Laser Data

Abstract Estimates of forest wood volume and biomass, and estimates of the surface area of asphalt, concrete, roof, and open water, were generated from a single set of airborne laser-profiling data acquired during the summer of 2000. Estimates of aboveground dry biomass for different types of land cover in each county or state were converted directly to estimates of standing carbon. A portable, inexpensive laser that measures forest canopy height and canopy cover was also used to identify and map mature forest stands that might support the Delmarva fox squirrel (Sciurus niger cinereus), an endangered species. Merchantable volume estimates were within 24 percent of US Forest Service estimates at the county level and within 15 percent statewide. Total aboveground dry biomass estimates were within 19 percent of US Forest Service estimates at the county level and within 16 percent statewide. Various types of impervious surfaces (roofs, concrete, asphalt) and open water were tallied along the flight lines to estimate areal coverage statewide, by land cover and county. Laser estimates of impervious surface area were within 28 percent of satellite-based estimates at the county level and within 3 percent at the state level. Laser estimates of open water were within 7 percent of photointerpreted geographic information system (GIS) estimates at the county level and within 3 percent of the GIS at the state level.

The use of airborne laser data to calibrate satellite radar altimetry data over ice sheets

Satellite radar altimetry is the most important data source for ice sheet elevation modeling but it is well established that the accuracy of such data from satellite borne radar altimeters degrade seriously with increasing surface slope and level of roughness. A significant fraction of the slope-correlated noise can be effectively removed by the so-called relocation error correction method. The adjustment, however, produces a different spatial sampling of the data, which introduces a non-negligible slope related bias to the computation of digital elevation models. In this paper we incorporate high-precision airborne laser profiling data from the so-called Arctic Ice Mapping project as a tool to determine that bias and to calibrate the satellite altimetry. This is achieved by a simple statistical analysis of the airborne laser profiles, which defines the mean amplitude of the local surface undulations as a linear function of surface slope. This linear correspondence is in turn tested as a model for adjusting the satellite altimetry data for the observed slope correlated bias. The adjustment is shown to have a significant effect in terms of reducing the bias, thus improving the modeling accuracy of the data.

Separating the ground and airborne laser sampling phases to estimate tropical forest basal area, volume, and biomass

Airborne laser profiling data were used to estimate the basal area, volume, and biomass of primary tropical forests. A procedure was developed and tested to divorce the laser and ground data collection efforts using three distinct data sets acquired in and over the tropical forests of Costa Rica. Fixed-area ground plot data were used to simulate the height characteristics of the tropical forest canopy and to simulate laser measurements of that canopy. On two of the three study sites, the airborne laser estimates of basal area, volume, and biomass grossly misrepresented ground estimates of same. On the third study site, where the widest ground plots were utilized, airborne and ground estimates agreed within 24%. Basal area, volume, and biomass prediction inaccuracies in the first two study areas were tied directly to disagreements between simulated laser estimates and the corresponding airborne measurements of average canopy height, height variability, and canopy density. A number of sampling issues were investigated; the following results were noted in the analyses of the three study areas. 1) Of the four ground segment lengths considered (25 m, 50 m, 75 m, and 100 m), the 25 m segment length introduced a level of variability which may severely degrade prediction accuracy in these Costa Rican primary tropical forests. This effect was more pronounced as plot width decreased. A minimum segment length was on the order of 50 m. 2) The decision to transform or not to transform the dependent variable (e.g., biomass) was by far the most important factor of those considered in this experiment. The natural log transformation of the dependent variable increased prediction error, and error increased dramatically at the shorter segment lengths. The most accurate models were multiple linear models with forced zero intercept and an untransformed dependent variable. 3) General linear models were developed to predict basal area, volume, and biomass using airborne laser height measurements. Useful laser measurements include average canopy height, all pulses (h̄a), average canopy height, canopy hits (h̄c) and the coefficients of variation of these terms (ca and cc). Coefficients of determination range from 0.4 to 0.6. Based on this research, airborne laser and ground sampling procedures are proposed for use for reconnaissance level surveys of inaccessible forested regions.

Thematic Mapper laser profile resolution of holocene lake limit, Great Salt Lake Desert, Utah

The limit of Great Salt Lake's maximum expansion onto the floor of the Great Salt Lake Desert during Holocene time is marked by a break in slope which is clearly depicted in terrain models which merge Thematic Mapper (TM) multispectral scanner data and Aerial Profiling of Terrain System (APTS) laser profile data. Mean elevations of APTS-coincident TM pixels are strongly correlated with reflectance in TM Bands 5 and 7 when and where sufficient moisture contrasts among terrain components are high. TM-APTS models and field surveys place the highest Holocene standing water at an elevation of 4221 ft (1286.7 m).

Airborne Laser Measurements of the Surface Topography of Simulated Concentrated Flow Gullies

ABSTRACT Concentrated flow (ephemeral) gully erosion is a significant source of soil loss from agricultural land in many parts of the United States. Currently, soil loss from these gullies is estimated using field measurements which are costly and time consuming. This paper describes a technique using an airborne laser profiler to measure the surface topography of concentrated flow gullies. Laser profile data, collected at aircraft altitudes of 50, 100 and 200 m over test gullies and analyzed using a moving average filter, clearly showed location, depth, and cross section of these simulated concentrated flow gullies. These results show the potential for using an airborne laser profiler to monitor changes in concentrated flow gullies. Better information on soil loss from concentrated flow gully erosion will allow conservation agencies to make better conservation assessments and plans for controlling soil loss.