Development of a computer software for the monitoring of subsidence

A computer software has been developed at the Faculty of Geoinformation Science and Engineering, UTM for the purpose of detecting subsidence of ground surface or manmade structure by using Visual Basic 6.0 and FORTRAN computer languages. This software can be used for processing data from GPS and precise levelling methods. The software requires GPS baseline vectors (∆X, ∆Y, ∆Z). Relative ellipsoidal heights based on the WGS84 ellipsoidal surface must be derived from these baseline vectors. The derived relative ellipsoidal heights are then adjusted using least square estimation method. The adjusted heights will be used for further subsidence analysis. Stransformation is used to transform results from least square estimation using minimum constraints to a selected datum. This paper examines the method of subsidence using the iterative weighted transformation. In this method, the stability of reference points must be checked through a single point test. Stable points will then be adjusted again together with object points. Lastly, the stability of object points will be determined. User of this software requires little knowledge on deformation monitoring processing, as the user needs to follow the procedure of inputting data required by the software. The output from the software will give the stability of the all control points whether they have moved or otherwise

Three dimensional asset documentation using terrestrial laser scanner technology

Asset documentation is a detailed record or inventory of the properties located within a room or a building. It is important to record the assets in case of property loss happen inside the premise especially when that premise caught fire, earthquake, robbery and others. The instrument used in this study is Faro Laser Scanner Photon 120/20. The object of the study is the computer room of Photogrammetry Lab, Faculty of Geoinformation and Real Estate. The final output of this study is the 3D model of the assets available inside the building. Before 3D model can be formed, the scanned data which is in the form of point cloud generated from the laser scanner have to be registered and georeferenced in order to combine the scans. The combine scans is the representation of the whole area of work surveyed from every scan points. These processes use Faro Scene, software that comes together with the laser scanner. By introducing this method, large scale asset documentation such as for factories and schools would be very beneficial rather than conventional method. The next process is to model the point cloud using AutoCAD 2011. Every item available on the room such as desks, chairs, cubicles, computers, whiteboard, projectors and cupboard are modeled and each of these items was inserted with attributes so that we can know the information of each item

Canopy height estimation from lidar data using open source software compared with commercial software

The goal of this study is to analyze the performance of Open Source Software (OSS) towards the generation of Digital Terrain Model (DTM) and Digital Surface Model (DSM), further on estimates the canopy height by using Light Detection and Ranging (LIDAR) data. Generation of DTM and DSM are very important in this research to ensure that better canopy height can be modeled. DTM and DSM commonly known as a digital representation of earth surface topography where DTM only represent the ground surface while DSM represent all the features including buildings and trees. Many software that have a function to generate DTM and DSM were developed recently. However, most software has been commercialized; therefore it requires a high expenditure to own the software. Advanced technology has lead to the emergence of the growing OSS. OSS is software that can be downloaded for free via the internet. By taking the forestry area of Pekan, Pahang for this research, LIDAR data for that particular area is processed by using the OSS Geographic Resources Analysis Support System (GRASS). To determine the effectiveness and capability of GRASS in the DTM and DSM generation, the same data were processed using commercial software which is TerraScan so that the result can be compared, further on better canopy height can be modele

Deformation monitoring by using the combination of geotechnical and geodetic observable

Large structures such as dams undergo deformation. Deformation monitoring is required to ensure the dams are secured during its operational life. Among the various scheme of monitoring, the deformation monitoring via geodetic method can be applied to obtain the status of displacement vector of the surface object points under investigation. Geotechnical observables are complementary to the geodetic network observables for the deformation modeling purpose. Geodetic network provides the absolute displacement vector of the object points on the surfaces of the body under investigation while the geotechnical measurement provides the relative displacement inside the body. This paper describes the combination scheme of the geodetic and geotechnical observables to determine the deformation model. The whole scheme of the computer program to handle the deformation analysis is also described. The preliminary results of some modules of the program are presented, followed by some important recommendations

Procedure for deformation detection using STARNET

The main steps in the deformation detection via geodetic methods are the least square estimation (LSE) of each epoch, and the deformation detection between epochs. This research focuses on the development of an interface programs called CONVERT, to integrate STARNET V6 (a commercial software) and our in-house software (DEFORM99 and GPSAD 2000), for deformation detection between two epoch (for 2D and 3D applications respectively). In this research, STARNET V6 is used first for LSE of each epoch due to its powerful adjustment capabilities. Next, CONVERT reads the special files created by STARNET, and create the appropriate input files for DEFORM99 and GPSAD 2000. An example is included to show the possibility of using output from STARNET for deformations detection applications

RETIME software for real time data acquisition using LEICA TCA series

Industrial survey is a discipline of engineering surveys that requires the utmost in achievable accuracies and real time data processing. The instrumentation used in conventional industrial survey requires long painstaking procedures with very skilled craftsmen to obtain the required results. Revolution of technology with the introduction of new instruments (such as total station, computer and software) has revolutionized industrial survey. The development of three dimensional (3D) coordinating system and total station interfaced to a microcomputer provides the capabilities for on line data gathering with simultaneous processing in 3D. This research concentrates on the development of software to acquire data from robotic total station (RTS) TCA2003 in real time. This software called RETIME is a short form of REal TIME. RETIME software consisted of the three core module i.e. (i) Data communication with RTS TCA2003, (ii) Calculate the raw data to produce 3D coordinates, and (iii) Convert the data from RETIME format into STAR*NET format. STAR*NET software (third party software) has been used in this research to provide an adjusted data. For verification purpose, RETIME software has been evaluated and the resulted are acceptable for industrial survey environment

Calibration and accuracy assessment of Leica ScanStation C10 terrestrial laser scanner

Requirement of high accuracy data in surveying applications has made calibration procedure a standard routine for all surveying instruments. This is due to the assumption that all observed data are impaired with errors. Thus, this routine is also applicable to terrestrial laser scanner (TLS) to make it available for surveying purposes. There are two calibration approaches: (1) component, and (2) system calibration. With the intention to specifically identify the errors and accuracy of the Leica ScanStation C10 scanner, this study investigates component calibration. Three components of calibration were performed to identify the constant, scale error, accuracy of angular measurement and the effect of angular resolution for distance measurement. The first calibration has been processed using closed least square solutions and has yielded the values of constant (1.2 mm) and scale error (1.000008879). Using variance ratio test (F-Test), angles observation (horizontal and vertical) for Leica C10 scanner and Leica TM5100A theodolite have shown significance difference. This is because the accuracy of both sensors are not similar and these differences are 0.01 and 0.0075º for horizontal and vertical measurements, respectively. Investigation on the resolution setting for Leica C10 scanner has highlighted the drawback of the tilt-and-turn target. Using the highest resolution, Leica Cyclone software only able to recognize the tilt-and-turn target up to 10 m distance compare to 200 m for the black and white target

Cephalometric measurements: comparison between analog X-Ray film and digital cephalometric image

This research is focused on the comparison of measurements between analog x-ray film and digital cephalometric image. This study is designed to determine the best measurement method between manually tracing and using computer software. Two (2) types of data from the same patient were used in this research. The data is analog x-ray film and digital cephalometric image (obtained from scanned x-ray film). A total of ten landmarks were used for comparison. All landmarks on the film and digital cephalometric image were traced using manual method (via tracing paper) and computerized method (via Rhinoceros 2.0 software) respectively. The landmarks were identified five times for each method to ensure the precision of the landmark identification. The results of landmark identification for both manual and computerize methods were compared by measurement of angle SNA, SNB, ANB and MMPA, and linear distance between Po-Or, PNS-ANS and Go-Me. This comparison gives the value of mean and standard deviation to show the best measurement method between manual and computerized approaches

Coordinate Systems Integration for Craniofacial Database from Multimodal Devices

This study presents a data registration method for craniofacial spatial data of different modalities. The data consists of three dimensional (3D) vector and raster data models. The data is stored in object relational database. The data capture devices are Laser scanner, CT (Computed Tomography) scan and CR (Close Range) Photogrammetry. The objective of the registration is to transform the data from various coordinate systems into a single 3-D Cartesian coordinate system. The standard error of the registration obtained from multimodal imaging devices using 3D affine transformation is in the ranged of 1-2 mm. This study is a step forward for storing the craniofacial spatial data in one reference system in database

Comparison of camera calibration parameters using Photomodeler and Australis

Photomodeler and Australis are two common photogrammetry software that provide camera calibration, and the camera calibration parameters. Each software uses different calibration approach (circular point detection in Australis and intersection of lines in Photomodeler). This paper compares the calibration parameters of Canon IXUS S400 PowerShot digital camera using both Photomodeler and Australis. During calibration, several images were taken with the same camera setting and the distance from the camera to the calibration field was 0.8 meter. All seven camera calibration parameters obtained from the software are compared and tested for statistical significance. The seven parameters are focal length, xp, yp, radial distortion ( K1 and K2 ) and tangential distortion ( P1 and P2 )