Search results for: Teemu Hakala

Items from 1 to 19 out of 19 results

chapter

CoAP over ICN

Nikos Fotiou, Hasan Islam, Dmitrij Lagutin, Teemu Hakala, more

2016 8th IFIP International Conference on New Technologies, Mobility and Security (NTMS) > 1 - 4

2016 8th IFIP International Conference on New Technologies, Mobility and Security (NTMS)

The Constrained Application Protocol (CoAP) is a specialized Web transfer protocol for resource-oriented applications intended to run on constrained devices, typically part of the Internet of Things. In this paper we leverage Information-Centric Networking (ICN), deployed within the domain of a network provider that interconnects, in addition to other terminals, CoAP endpoints in order to provide...

article

Remote Sensing of 3-D Geometry and Surface Moisture of a Peat Production Area Using Hyperspectral Frame Cameras in Visible to Short-Wave Infrared Spectral Ranges Onboard a Small Unmanned Airborne Vehicle (UAV)

Eija Honkavaara, Matti A. Eskelinen, Ilkka Polonen, Heikki Saari, more

IEEE Transactions on Geoscience and Remote Sensing > 2016 > 54 > 9 > 5440 - 5454

Miniaturized hyperspectral imaging sensors are becoming available to small unmanned airborne vehicle (UAV) platforms. Imaging concepts based on frame format offer an attractive alternative to conventional hyperspectral pushbroom scanners because they enable enhanced processing and interpretation potential by allowing for acquisition of the 3-D geometry of the object and multiple object views together...

chapter

Range calibration of airborne profiling radar used in forest inventory

Ziyi Feng, Yuwei Chen, Teemu Hakala, Juha Hyyppa

2016 IEEE International Geoscience and Remote Sensing Symposium (IGARSS) > 6672 - 6675

IGARSS 2016 - 2016 IEEE International Geoscience and Remote Sensing Symposium

In this paper, a range calibration and modulation sweep linearity verification method of a helicopter-borne FM-CW (Frequency-Modulated Continuous Waveform) profiling radar are presented. The radar is designed to collect backscatter signal waveforms to build target stand profiles. Various forest elements e.g. tree height; density; species, etc. can be evaluated through this profiling radar. This paper...

article

Optical measurements of chemically heterogeneous particulate surfaces

Nataliya Zubko, Maria Gritsevich, Evgenij Zubko, Teemu Hakala, more

Journal of Quantitative Spectroscopy and Radiative Transfer > 2016 > 178 > C > 422-431

We experimentally study light scattering by particulate surfaces consisting of two high-contrast materials. Using the Finnish Geodetic Institute field goniospectropolarimeter, reflectance and degree of linear polarization are measured in dark volcanic sand, bright salt (NaCl) and bright ferric sulfate (Fe₂(SO₄)₃); and in mixtures of bright and dark components. We found that the light-scattering response...

chapter

Scan matching technology for forest navigation with map information

Yuwei Chen, Jian Tang, Ehsan Khoramshahi, Teemu Hakala, more

2016 IEEE/ION Position, Location and Navigation Symposium (PLANS) > 198 - 203

2016 IEEE/ION Position, Location and Navigation Symposium - PLANS 2016

The topic of positioning in dense forest has attracted researchers' attention in the last few decades. Currently, accurate and robust positioning in complex forest environment is still not available by using standalone GNSS, and it is a major drawback for forestry automation. Laser scanning-based SLAM demonstrated its potential as an alternative positioning solution in dense boreal forest environment...

chapter

Reflectance of various snow types: measurements, modeling, and potential for snow melt monitoring

Jouni I. Peltoniemi, Juha Suomalainen, Teemu Hakala, Jyri Näränen, more

Environmental Sciences > Light Scattering Reviews 5 > Optical Properties of Bright Surfaces and Regoliths > 393-449

Seasonal snow covers large parts of the northern hemisphere annually. It can change the albedo of the surfaces from dark to bright overnight (and back), causing significant climate feedback (Manninnen and Stenberg, 2008; Flanner and Zender, 2006; Pirazzini, 2008; Nolin and Frei, 2001; Roesch et al., 2001). It forms large energy reservoirs which can be exploited by hydro energy power plants, and is...

article

Growth and development of Norway spruce and Scots pine seedlings under different light spectra

Johanna Riikonen, Nelli Kettunen, Maria Gritsevich, Teemu Hakala, more

Environmental and Experimental Botany > 2016 > 121 > C > 112-120

The goal of this study was to examine how different light spectra affect growth and development of Norway spruce (Picea abies) and Scots pine (Pinus sylvestris) seedlings. The seedlings were grown in a darkened greenhouse under four light spectra consisting of different proportions of blue (B, 400–500nm), red (R, 600–700nm), and far-red (FR, 700–800nm) light, with high-pressure sodium lamps (HPS)...

article

Corrigendum to “Technical notes: A detailed study for the provision of measurement uncertainty and traceability for goniospectrometers” [J. Quant. Spectrosc. Radiat. Transf. 146 (2014) 376–390]

Jouni I. Peltoniemi, Teemu Hakala, Juha Suomalainen, Eija Honkavaara, more

Journal of Quantitative Spectroscopy and Radiative Transfer > 2015 > 152 > Complete > 166

article

Fast and nondestructive method for leaf level chlorophyll estimation using hyperspectral LiDAR

Olli Nevalainen, Teemu Hakala, Juha Suomalainen, Raisa Mäkipää, more

Agricultural and Forest Meteorology > 2014 > 198-199 > Complete > 250-258

We propose an empirical method for nondestructive estimation of chlorophyll in tree canopies. The first prototype of a full waveform hyperspectral LiDAR instrument has been developed by the Finnish Geodetic Institute (FGI). The instrument efficiently combines the benefits of passive and active remote sensing sensors. It is able to produce 3D point clouds with spectral information included for every...

article

Technical notes: A detailed study for the provision of measurement uncertainty and traceability for goniospectrometers

Jouni I. Peltoniemi, Teemu Hakala, Juha Suomalainen, Eija Honkavaara, more

Journal of Quantitative Spectroscopy and Radiative Transfer > 2014 > 146 > Complete > 376-390

The measurement uncertainty and traceability of the Finnish Geodetic Institutes׳s field gonio-spectro-polarimeter FIGIFIGO have been assessed. First, the reference standard (Spectralon sample) was measured at the National Standard Laboratory of MIKES-Aalto. This standard was transferred to FGI׳s field reference standard (larger Spectralon sample), and from that to the unmanned aerial vehicle (UAV),...

article

Hemispherical-directional reflectance factor measurements of snow on the Greenland Ice Sheet during the Radiation, Snow Characteristics and Albedo at Summit (RASCALS) campaign

Teemu Hakala, Aku Riihelä, Panu Lahtinen, Jouni I. Peltoniemi

Journal of Quantitative Spectroscopy and Radiative Transfer > 2014 > 146 > Complete > 280-289

During the summer of 2010 a snow measurement campaign was carried out at Greenland Environmental Observatory, on Greenland Ice Sheet. Broadband snow albedo (bihemispherical reflectance), spectral hemispherical conical reflectance factor, temperature, density and other physical parameters were measured. Especially, the Hemispherical Directional Reflectance Factor (HDRF) of 46 snow samples was measured...

chapter

The uses of ambient light for ubiquitous positioning

Jingbin Liu, Yuwei Chen, Anttoni Jaakkola, Teemu Hakala, more

2014 IEEE/ION Position, Location and Navigation Symposium - PLANS 2014 > 102 - 108

2014 IEEE/ION Position, Location and Navigation Symposium - PLANS 2014

This paper proposed ambient light (ambilight) as a new type of signal sources for positioning. The possibility and methods of ambilight positioning were presented in this paper. It has been shown that two kinds of observables of ambient light can be used for positioning through different principles. Ambilight intensity spectrum measurements have highly location dependency, and they can be used for...

article

Classification of Spruce and Pine Trees Using Active Hyperspectral LiDAR

Jari Vauhkonen, Teemu Hakala, Juha Suomalainen, Sanna Kaasalainen, more

IEEE Geoscience and Remote Sensing Letters > 2013 > 10 > 5 > 1138 - 1141

Most forest inventories based on the use of remote-sensing data produce the required species-specific information by fusing data from different sources (e.g., Light Detection And Ranging (LiDAR) and spectral data). We tested an active hyperspectral LiDAR instrument in a laboratory measurement of spruce and pine trees to find out whether these species could be separated by means of combined range and...

article

Demonstration of a virtual active hyperspectral LiDAR in automated point cloud classification

Juha Suomalainen, Teemu Hakala, Harri Kaartinen, Esa Räikkönen, more

ISPRS Journal of Photogrammetry and Remote Sensing > 2011 > 66 > 5 > 637-641

In this paper, a measurement system for the acquisition of a virtual hyperspectral LiDAR dataset is presented. As commercial hyperspectral LiDARs are not yet available, the system provides a novel type of data for the testing and developing of future hyperspectral LiDAR algorithms. The measurement system consists of two parts: first, backscattered reflectance spectra are collected using a spectrometer...

article

Tree species classification from fused active hyperspectral reflectance and LIDAR measurements

Eetu Puttonen, Juha Suomalainen, Teemu Hakala, Esa Räikkönen, more

Forest Ecology and Management > 2010 > 260 > 10 > 1843-1852

A new terrestrial laser system was tested for tree species classification. A dataset consisting of shape parameters of three boreal tree species was collected with Light Detection and Ranging (LIDAR) and integrated with an actively measured reflectance hyperspectra. Tree species were classified using parameters derived from reflectance spectra and point cloud shape distribution. Classification performance...

article

Radiometric stability assessment of an airborne photogrammetric sensor in a test field

Lauri Markelin, Eija Honkavaara, Teemu Hakala, Juha Suomalainen, more

ISPRS Journal of Photogrammetry and Remote Sensing > 2010 > 65 > 4 > 409-421

Radiometric stability is a desired property of digital photogrammetric large-format sensors. This article presents a methodology for determining the radiometric stability of airborne imaging sensors in operational conditions in a test field and the results of stability evaluation of a large-format photogrammetric frame sensor DMC, from Intergraph. The imagery was collected in two days using nine different...

chapter

Active hyperspectral LIDAR methods for object classification

Sanna Kaasalainen, Juha Suomalainen, Teemu Hakala, Yuwei Chen, more

2010 2nd Workshop on Hyperspectral Image and Signal Processing: Evolution in Remote Sensing > 1 - 4

2010 2nd Workshop on Hyperspectral Image and Signal Processing: Evolution in Remote Sensing (WHISPERS 2010)

We have studied the fusion of active hyperspectral and range (LIDAR) data to investigate the concept of an active hyperspectral LIDAR and its potential applications in the remote sensing of vegetation. We have built two prototype instruments using the newly developed supercontinuum laser technique providing a continuous spectrum, which has then been used both for combined hyperspectral and LIDAR or...

article

Polarised bidirectional reflectance factor measurements from soil, stones, and snow

Jouni Peltoniemi, Teemu Hakala, Juha Suomalainen, Eetu Puttonen

Journal of Quantitative Spectroscopy and Radiative Transfer > 2009 > 110 > 17 > 1940-1953

The bidirectional reflectance factor and degree of linear polarisation of selected snow, soil, and gravel types have been measured using Finnish geodetic institute field goniospectropolariphotometer (FIGIFIGO). It was observed that with all measured samples the degree of linear polarisation is weakest 0–30∘ backwards from nadir, turning 1–5% negative in the backward direction, and growing larger (5–50%)...

article

Polarised bidirectional reflectance factor measurements from vegetated land surfaces

Juha Suomalainen, Teemu Hakala, Eetu Puttonen, Jouni Peltoniemi

Journal of Quantitative Spectroscopy and Radiative Transfer > 2009 > 110 > 12 > 1044-1056

This study measured the spectral bidirectional reflectance factors of selected vegetated land surfaces in two linear polarisation directions. It was observed that the degree of linear polarisation is usually weakest near nadir, turning 1–5% negative in the backward direction, and growing larger in the forward and Brewster directions. Polarisation was found to be inversely but non-linearly proportional...

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