Thinning is one of the most important silvicultural activities in middle aged forests, partly to minimize damages and partly because it leads to earlier harvesting revenues and increases the value of the remaining trees. There are many different indices used to describe stand density and thereby the need of thinning in forests today. Studies have shown that forest variables can be estimated with high accuracy using airborne laser scanning and it is likely that the method could also be used to estimate forest density indices. In this study, the possibility of using the forest density index ?H² to determine and map priorities for thinning operations for a forest area was examined.

Denna uppsats avhandlar möjligheter och begränsningar vid användande avhögenergilaser för nedskjutning av luftmål. Uppsatsen har inte ambitionen attvara heltäckande över området utan presenterar några av de fördelar ochnackdelar som finns..

The thesis mission is to investigate whether the swiveling laser that Vectura (former Vägverket Konsult) has in use to measure the road areas and straddle measuring can be used to detect differences in the reflective road markings function. This is to increase use of the swiveling laser and get rid of the manual measurements performed today.Currently, the measurement of road markings reflective function is performed with both mobile and handheld measuring instruments. The purpose of this thesis is to develop better methods for determination of road markings? reflective function, in order to facilitate the description and suggestions for improvements of the maintenance of road markings reflective function.The questions that the thesis has been to start with are:Can the swiveling laser detect differences in longitudinal and transverse road markings reflective function?The accuracy of measurement has been sweeping the laser over the reference instrument (LTL-2000)Is it necessary with a conversion factor for swiveling laser data against the reference instrument data?To answer the question 2 and 3, there has been a field work in Värnamo where a road stretch with longitudinal road markings and zebra crossing (transverse road markings) has been investigated with a swiveling laser and LTL-2000.The formulas and calculations contained in the thesis are drawn from scientific reports that are produced by VTI in Linköping. The same formula that was used to calculate the optical measurement data was also used for the swiveling laser data.

This thesis discusses model based tracking of radar echoes in tanks with liquid content. The errors in the measurements are not always random in these cases, and the interference that occurs when nearby echoes moves in relation to each other makes tracking difficult. The tracking problem can be broken down to four parts; track initiation, track destruction, association of the measured echoes to the tracks and to update the tracks with the associated echoes. The radar measurement is primarily made on the surface. However, additional echoes from the tank floor or other structures and double bounces are normally present.

The purpose of this report is to explore how modern technology can work againstolder craft techniques. The focus of the research will depend on what conditions areoptimal for cutting marquetry with laser technology. In my work I account for thehistorical background of the various techniques and then through own practical testsexamine whether the laser technology can complement the traditional techniques..

This report describes a Bachelor thesis work in which a robotised laser welding cell has been modelled and simulated for the purpose of making a presentation movie. The report shows that the work has been concentrated on making the movie from the modelling phase through the recording of the movie and ending up with the editing of the final presentation movie. A pre-study was made prior the Bachelor thesis work. In the pre-study a literature study was conducted about measurement and calibration of a welding cell. Measurement of almost all equipment in the entire cell was also conducted in the pre-study.

Den här rapporten beskriver och utvärderar ett antal algoritmer för multisensordatafusion av radar och IR/TV-data på rådatanivå. Med rådatafusion menas att fusionen ska ske innan attribut- eller objektextrahering. Attributextrahering kan medföra att information går förlorad som skulle kunna förbättra fusionen. Om fusionen sker på rådatanivå finns mer information tillgänglig och skulle kunna leda till en förbättrad attributextrahering i ett senare steg. Två tillvägagångssätt presenteras.

The waveform of a radar signal affects the resolution in velocity and distance. The ambiguity function is used as an aid for analysing narrow band radar signals simultaneously in time and frequency. An analysing tool for wide band radar signals is missing.This thesis describes a generalised ambiguity function to be utilised for study of wide band signals. Waveforms are further synthesised with help of the developed analysing tool. The aim is to start with a certain ambiguity function and find a waveform that reproduces the same ambiguity function.Mathematical formulas are presented and implemented in Matlab to produce the wide band ambiguity function.

An investigation of the heat impact of laser cutting on the material properties when producing tensile and impact test specimens of different steel types of varying thickness has been performed. The purpose of the thesis project was to provide recommendations regarding how much material that needs to be milled from the laser cut edge before tensile and impact tests. The study has been performed partly by investigating the test specimens by heat camera when the specimens were cut in the laser cutting line and partly by performing hardness tests, investigation by microscopy, and tolerance and roughness measurements and tensile tests of the laser cut material and material produced in the traditional multi operation machine. The results show that the heat affected zone in the thicker materials is greater than previously thought of, and that the currently used recommendation has to be adjusted. The study clearly shows that the thicker the material, the greater the heat affected zone, independently of the steel type, since the thicker material takes longer time to cut.

Bergvik Skog is one of the leading forest companies in Sweden who use airborne laser scanning for forestry information. They utilize laser data retrieved by the Swedish National Land Survey to describe the forest holdings and facilitate planning for thinning and final felling operations. However, the possibility to identify stands with clearing needs by using laser scanning data has not been tested in a large scale. The data used in the current study are field data from The Swedish National Forest Inventory in combination with laser data from the Swedish National Land Survey acquired in 2009. The collected data is used to find one or several laser variables that best describe the relationship of the field measured samples with clearing needs.

This master thesis includes a description of how a number of sensors are put together in a sensor platform. It also gives a description of how localization and mapping has been performed with data collected from the sensor platform. Localization is a prerequisite for most of the tasks that can be requested from an autonomous mobile robot. In many situations the GPS signal is not available and hence an additional localization system is required. One approach is to apply localization based on landmarks extracted from the robots surrounding.

An investigation of the heat impact of laser cutting on the material properties when producing tensile and impact test specimens of different steel types of varying thickness has been performed. The purpose of the thesis project was to provide recommendations regarding how much material that needs to be milled from the laser cut edge before tensile and impact tests. The study has been performed partly by investigating the test specimens by heat camera when the specimens were cut in the laser cutting line and partly by performing hardness tests, investigation by microscopy, and tolerance and roughness measurements and tensile tests of the laser cut material and material produced in the traditional multi operation machine. The results show that the heat affected zone in the thicker materials is greater than previously thought of, and that the currently used recommendation has to be adjusted. The study clearly shows that the thicker the material, the greater the heat affected zone, independently of the steel type, since the thicker material takes longer time to cut.

This master?s thesis is a remote sensing study of an area-based method used to detect forest in need of thinning by use of laser data and field samples. Only pine-dominated forest has been included in the study and height limits were set to match empirical restrictions. The study area was in the municipality of Älvsbyn (Latitude 65° 40´ N, Longitude 21° 00´ E), in northern Sweden.The Swedish authority Lantmäteriet is currently laser scanning most parts of Sweden, providing new opportunities and applications. The primary aim of the national laser scanning is to create a new elevation model, useful in consequence analysis of climate changes.

Data retrieved from airborne laser scanning represents a new source of forest data. Today, the technology has matured so that it can function in an operational environment. The aim of this study was to compile areas of application of laserdata in forestry. Moreover to analyze costs and accessibility of laserdata. The goal was to provide private forest owners information to support assessments of possible benefits of laserdata.

 The purpose with this thesis was to develop a designguideline which will simplify the development of new products that will be laser welded. The need for this thesis has come forward from the quality problems that Volvo Construction Equipment, Components Division is having with their laser welding manufacturing unit. The reason for the problems emerges from the bad communication between the development unit and the manufacturing unit within the company when the products produced today was developed. This resulted in products that were hard to and in some cases almost impossible to weld. To avoid these problems from occurring again it was needed to gather the experiences within this area and compile it and present in a brief a pedagogical manner. The information for the groundwork of our results has been gathered by interviews of several key persons in Volvo Construction Equipment, Components Division.