Khairul Nizam Tahar

Digital aerial imagery of unmanned aerial vehicle for various applications

Digital aerial imagery (DAI) can be acquired using digital mapping camera attached to light aircraft. The DAI is used for the production of topographic and thematic map. The cost of acquiring DAI is very expensive and suitable for large area coverage. The acquisition of DAI is not economical and suitable for small area coverage. Therefore an alternative method should be used to fulfill this need. There are two alternative methods that can be used for acquisition of DAI which include using a small format digital camera attached to light aircraft and using a small format attached to an unmanned aerial vehicle (UAV). UAV system has been reported used in various and diversified applications such as mapping applications (eg. map revision, landslide, coastal erosion, archaeology, forestry), industrial application (eg. engineering, crash accident), Geographic Information System (GIS) applications and others. In this study, micro unmanned aerial vehicle (UAV) systems which comprise of fixed wing UAV flying and rotary UAV are attached with small format high resolution digital camera to acquire DAI for the purpose of mapping at the flying height of 300m at 100m respectively. The micro UAVs were flown autonomously (i.e automatically) and a series of DAIs of a slope using fixed wing UAV and a stream using rotary UAV were acquired rapidly within short period. Ground control point (GCP) and check point (CP) were established using the Global Positioning System and conventional Total Station techniques around the study area for the slope and stream respectively for the purpose of digital image processing and accuracy assessment. The DAIs were processed to produce photogrammetric output such as digital elevation model (DEM) and orthophoto. All these photogrammetric products were successfully produced and assessed. The achievable accuracy is less than ±1m for slope mapping and ±0.280m for stream mapping. In this study, it is proven that the micro UAV system can be used for mapping which cover small area. As conclusion, micro UAV is suitable for mapping small area, rapid data acquisition, accurate, low cost and can be employed for various applications.

A simulation study on the capabilities of rotor wing unmanned aerial vehicle in aerial terrain mapping

Many applications can be solved by using the unmanned aerial vehicle (UAV) technology such as farming, surveillance, monitoring, fire disaster, flood monitoring and aerial terrain mapping. This study was carried out to investigate the use of light weight rotary-wing UAV for mapping simulation model. The accuracy of photogrammetric product will be assessed as one of the objectives of this study. There are two types of UAV units known as rotor wing and fixed-wing. Based on few studies, rotor wing units are more stable and are able to capture images easily. It allows remote control UAV to be practiced in the environment and urban mapping. In the simulation model, ground control points (GCP) and checked point (CP) were established using total station. The GCP is used in the photogrammetric processes to produce photogrammetric output while the CP is used for accuracy assessment. This study also used a low cost digital camera in image acquisition to capture the aerial image of a simulated model. Two methods were implemented in this study. In the first method, the camera was mounted vertically at a fixed height on the simulated model. In the second method, the camera was mounted vertically; it was then attached at the bottom of rotary-wing UAV and the images were captured at an altitude. The productions of digital orthophoto and digital elevation model of the simulated model were obtained after the acquired images were processed using the photogrammetric software. Based on the finding, the root mean square errors (RMSEs) for fixed platform are ±0.002, ±0.001 and ±0.214 for coordinate x, y and z, respectively while the RMSE for UAV platform are ±0.002, ±0.002 and ±0.223 for coordinate x, y and z, respectively. It can be concluded that the differences between the mobile and fixed platforms are small. In conclusion, UAV system can be used for large scale mapping of aerial terrain mapping.

UAV-based stereo vision for photogrammetric survey in aerial terrain mapping

Recently, Unmanned Aerial Vehicle (UAV) technology is becoming useful to solve problems in many applications. The aim of this study is to investigate the use of light weight rotary-wing UAV for mapping simulation model. The objective of this study is to determine the accuracy of the photogrammetric output. This study only concentrates on one type of rotor-wing UAV. It is because rotor-wing units are more stable and able to capture images easily. It allows remote control UAV to be practiced in any environment and urban mapping. In the simulation model, ground control points (GCP) and checked point (CP) were established using total station. The GCP is used in the photogrammetric processes to produce photogrammetric output while the CP is used for accuracy assessment. A Nikon Coolpix consumer digital camera was used for images acquisition of the simulation model where two methods were used. In the first method, the camera was mounted vertically in a rotary-wing UAV and captured the images at an altitude. In the second method, the camera is mounted vertically at a fixed height. The acquired images were processed using photogrammetric software to produce orthophoto and digital elevation model of the simulation model. From this study, it was found that root mean square errors for fixed platform are ±0.002m, ±0.001m, ±0.214m for coordinate x, y and z respectively while the root mean square errors for mobile platform are ±0.002m, ±0.002m, ±0.223m for coordinate x, y and z respectively. It can be concluded that the differences between the mobile and fixed platforms are not significant. In conclusion, UAV system can be used for large scale mapping for aerial terrain mapping.

Capability of low cost digital camera for production of orthophoto and volume determination

This paper discusses about the use of low cost digital camera or known as non metric camera as photogrammetry tool for speeding up the process of acquiring aerial data. Digital camera can also be categorized as non metric camera. In photogrammetry, digital camera has been used for many diversified applications either in aerial photogrammetry or close range photogrammetry. The digital camera also has the potential to be used for landslide mapping and monitoring. In this study, a low cost digital camera has been used to acquire digital images of a simulated model build from sand and cement (dimension of 1m × 3m) which represent some form of topographic surface. In the simulated model, an area was excavated to simulate landslide occur in the area. The acquired digital images of the simulated model were then processed using photogrammetric technique to the final photogrammetric output that is the digital orthophoto. The digital camera used is of high resolution and suitable for large scale mapping which does not involve large study area, require moderate accuracy and limited budget. The objective of this study is to investigate the capability of a low cost digital camera in generating three dimensional models, digital elevation model (DEM) and finally the digital orthophoto. The other objective of this study is to investigate whether the data captured using the digital camera can be used for volume determination that was excavated from an area in the simulated model. The results of the study showed that the low cost digital camera is capable of producing digital orthophoto and capable of determining the excavated volume of the simulated model.

Digital Terrain Model extraction using digital aerial imagery of Unmanned Aerial Vehicle

Digital Terrain Model (DTM) is extensively applied in various fields such as surveying and construction engineering, natural disaster management system, structure monitoring, and many more. Generally, the demand on accuracy and very detail information of DTM extraction is crucial for most of the applications. The advancement of photogrammetry and spin-off technology has advantageous in extracting highly accurate DTM. Currently, the DTM can be extracted from digital aerial imagery of small format camera mounted on light weight platform such as Unmanned Aerial Vehicle (UAV). The study is performs to assess the accuracy of DTM derived from UAV platform. Canon PENTAX W90 is utilized as non-metric camera for the earth information acquisition. In this study, 23 points of three dimensional coordinates (3D) were established using real time kinematic Global Positioning System (RTK-GPS) technique. Sixteen points are used in ground control point (GCP) for the purposes of aerial triangulation while seven as check point (CP) for accuracy assessment. The research output is then evaluated for planimetry and vertical accuracy using root mean square error (RMSE). Based on the analysis, sub-meter accuracy is obtained. As conclusion, UAV digital imagery can be used for accurate applications.

Wireless fire detection monitoring system for fire and rescue application

The purpose of the Fire and Rescue Service is to protect human life, our property, and Earth natural resources from fire and other emergencies. With fluctuation in demands, the Fire and Rescue Service must equip with the best techniques, training regime and equipment to meet public expectations. Mitigation, preparedness and risk management have taken on new benefit with challenges facing the fire service today. Fast response cannot be achieved without good planning and preparedness. As a result, a monitoring system of alarm for fire detection using Arduino microcontroller was design. The circuit are includes with a buzzer, smoke sensor and a camera. All the data taken from smoke sensor and camera will be send to data monitoring system and be display on monitoring system wirelessly.

Unmanned Aerial Vehicle Photogrammetric Results Using Different Real Time Kinematic Global Positioning System Approaches

This chapter describes photogrammetric results based on unmanned aerial vehicle (UAV) images for slope mapping. This chapter discussed the effect of photogrammetric results based on different observation time and network adjustment of Real Time Kinematic Global Positioning System (RTK GPS) in photogrammetric image processing. A complete set of fixed wing UAV with autonomous flight was used to capture image from certain altitude at the study area. All acquired images were processed using photogrammetric software. Two primary results were produced in this study namely digital elevation model and digital orthophoto. Analyses were carried out to determine the best RTK GPS data based on time and network during photogrammetric image processing. It was found that, RTK GPS adjustment from known point with 10 minutes observation time gives greater accuracy compared to the local network adjustment. In conclusion, UAV has potential in the slope mapping because it can provide high accuracy photogrammetric results.

3D accident reconstruction using low-cost imaging technique

Close range photogrammetry technique to investigate the traffic incident scene.Police officer-conventional technique-collect data-traffic incident scene.This research-investigate traffic incident scene using the imaging technique.Evaluates the accuracy of data based on mathematical model.CRP in accident reconstruction-effective-achieve a cm-level accuracy. This research is about the implementation of close range photogrammetry (CRP) technique to investigate the traffic accident scene. CRP technique representing and measuring the 3D objects using data stored in 2D photographs. It is non-contact measurement requiring multiple pictures capture to measure objects of interest. Currently, a police officer uses a conventional technique to collect data on traffic accident scene using tape measurement in order to reconstruct the accident scene. The development of camera technology increases the efficiency, stability of consumer grade digital cameras for photogrammetric applications. This development can help police officer to apply a CRP technique for data collection on traffic accident scene. CRP technique offers fast data acquisition, and only need one officer during data capture. This research is to investigate traffic accident scene using the imaging technique. The methodology of this research used a measuring tape and total station for data acquisition on traffic accident scene. This research also evaluates the accuracy of data based on mathematical model standard deviation and root mean square error (RMSE). Based on this research, the implementation of CRP in accident reconstruction is very effective because can achieve a cm-level accuracy in range 40m traffic accident scene.

A generic approach for photogrammetric survey using a six-rotor unmanned aerial vehicle

This paper discusses a rapid production of slope mapping using multi-rotor unmanned aerial vehicle (UAV). The objective of this study is to determine the accuracy of the photogrammetric results based on novel method of multi-rotor UAV images as well as to analyze the slope error distribution that are obtained from the UAV images. This study only concentrates on multi-rotor UAV which also known as Hexacopter. An operator can control the speed of multi-rotor UAV during flight mission. Several ground control points and checkpoints were established using Real Time Kinematic Global Positioning System (RTK- GPS) at the slope area. Ground control points were used in exterior orientation during image processing in sequence to transform image coordinates into local coordinate system. Checkpoints were established at the slope area for accuracy assessment. A digital camera, Sony NEX-5N was used for image acquisition of slope area from UAV platforms. The digital camera was mounted vertically at the bottom of UAV and captured the images at an altitude. All acquired images went through photogrammetric processing including interior orientation, exterior orientation and bundle adjustment using photogrammetric software. Photogrammetric results such as digital elevation model, and digital orthophoto including slope map were assessed. UAV is able to acquire data within short period of time with low budget compared to the previous methods such as satellite images and airborne laser scanner. Analysis on slope analysis and error distribution analysis are discussed in this paper to determine the quality of slope map in the area of interest. In summary, multi-rotor UAV is suited in slope mapping studies.

A comparative study of template matching, ISO cluster segmentation, and tree canopy segmentation for homogeneous tree counting

ABSTRACT Counting trees can be challenging due to the crowded environment, time-consuming, and expensive operation. The information on the locations and the number of oil palm trees in a plantation area is important in many aspects. First, it is important to predict the yield of palm oil, which is the most widely used vegetable oil in the world. Second, it provides essential information to understand the growing situation of palm trees after plantation, such as the age or the survival rate of the palm trees. As such, this research investigated tree counting extraction of oil palm plantation. The research area is located at an oil palm plantation area (Felda Pasir Raja) in Johor, Malaysia. Three methods of extraction had been used in this research, i.e. Template Matching Algorithm (TMA), ISO Cluster Unsupervised Classification (ICUC), and Tree Canopy Segmentation (TCS). The results obtained using TCS emerged as the best method for tree counting in this research. The number of the trees detected by the TCS method was 77,963 trees, while its percentage was 96%. As for TMA and ICUC, the percentages were 89% and 82%, respectively. Therefore, this research could be used amongst the plantation organisations, especially the oil palm industries, which are responsible to monitor the status of oil palm trees for effective palm oil production.