Browsing by Author "Skauli, Torbjørn"
Now showing items 1-20 of 24
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Characterization of a compact 6-band multifunctional camera based on patterned spectral filters in the focal plane
Torkildsen, Hans Erling; Hovland, Harald; Opsahl, Thomas Olsvik; Haavardsholm, Trym Vegard; Nicolas, Stephane; Skauli, Torbjørn (2014)In some applications of multi- or hyperspectral imaging, it is important to have a compact sensor. The most compact spectral imaging sensors are based on spectral filtering in the focal plane. For hyperspectral imaging, ... -
Characterizing the dynamic range of a hyperspectral camera
Skauli, Torbjørn (2021-04-12)The dynamic range of a hyperspectral camera can have a strong impact on the quality and integrity of the collected spectra. For the image sensor chip alone, the dynamic range is the ratio between the saturation level and ... -
Combined range ambiguity resolution and noise reduction in lidar signal processing
Arisholm, Gunnar; Skauli, Torbjørn; Landrø, Stig Endre (2018)When the interval between transmitted pulses is shorter than the time of flight, it is not straightforward for a lidar to determine the distance uniquely. We present a method that uses varying pulse intervals, constructs ... -
Compact camera for multispectral and conventional imaging based on patterned filters
Skauli, Torbjørn; Torkildsen, Hans Erling; Nicolas, Stephane; Opsahl, Thomas Olsvik; Haavardsholm, Trym Vegard; Kåsen, Ingebjørg; Rognmo, Atle (2014)A multispectral camera concept is presented. The concept is based on using a patterned filter in the focal plane, combined with scanning of the field of view. The filter layout has stripes of different bandpass filters ... -
Compact multimodal multispectral sensor system for tactical reconnaissance
Haavardsholm, Trym Vegard; Opsahl, Thomas Olsvik; Skauli, Torbjørn; Stahl, Annette (Society of Photo-Optical Instrumentation Engineers (SPIE), 2022-09-30)Multispectral imaging is an attractive sensing modality for small unmanned aerial vehicles (UAVs) in numerous military and civilian applications such as reconnaissance, target detection, and precision agriculture. Cameras ... -
Compact multispectral multi-camera imaging system for small UAVs
Torkildsen, Hans Erling; Haavardsholm, Trym Vegard; Opsahl, Thomas Olsvik; Datta, Urmila; Skaugen, Atle; Skauli, Torbjørn (2016)Cameras with filters in the focal plane provide the most compact solution for multispectral imaging. A small UAV can carry multiple such cameras, providing large area coverage rate at high spatial resolution. We investigate ... -
Cost-Effective Flight Strategy for Aerial Thermography Inspection of Photovoltaic Power Plants
Lofstad-Lie, Victoria; Marstein, Erik Stensrud; Simonsen, Aleksander; Skauli, Torbjørn (2022-11-06)Thermography from unmanned aerial vehicles (UAV) is widely used for module condition surveys and defect detection in solar (photovoltaic) power plants. This article presents an optimized defect inspection procedure in which ... -
Deteksjon av eksplosivrester i felt ved hjelp av hyperspektral avbildning
Karsrud, Tove; Parmer, Marthe Petrine; Skauli, Torbjørn (2009)Der er kjent at det i Forsvarets skytefelt ligger rester av eksplosiver, noe som hovedsakelig skyldes ufullstendig detonasjon av ammunisjon. Disse restene er vanskelige å finne, men er ansett å være et miljøproblem blant ... -
Enhancing far-field thermal emission with thermal extraction
Yu, Zongfu; Sergeant, Nicholas P.; Skauli, Torbjørn; Zhang, Gang; Wang, Hailiang; Fan, Shanhui (2013)The control of thermal radiation is of great current importance for applications such as energy conversions and radiative cooling. Here we show theoretically that the thermal emission of a finite-size blackbody emitter can ... -
Feasibility of a standard for full specification of spectral imager performance
Skauli, Torbjørn (2017)The current state of the art of specifying spectral imagers falls short of what is needed. Commercial datasheets do not adequately reflect the performance of hyperspectral imagers offered as standard products. In particular, ... -
Full characterization of spatial coregistration errors and spatial resolution in spectral imagers
Torkildsen, Hans Erling; Skauli, Torbjørn (2018)For multi- and hyperspectral imagers, the integrity of the spectral information depends critically on the spatial coregistration between bands. There is at present no commonly accepted way to fully specify coregistration ... -
Information capacity as a figure of merit for spectral imagers: the trade-off between resolution and coregistration
Skauli, Torbjørn (2013)The performance of spectral imagers is customarily described by several characteristics including resolution, noise, and coregistration. These must be traded off against each other in a practical imager design. This paper ... -
Measurement of point spread function for characterization of coregistration and resolution: Comparison of two commercial hyperspectral cameras
Torkildsen, Hans Erling; Skauli, Torbjørn (2018)For spectral cameras, the spatial resolution and coregistration of bands are important performance characteristics. The paper discusses how these can be quantified in a way that is relevant for the spectroscopic processing ... -
Multimodal Multispectral Imaging System for Small UAVs
Haavardsholm, Trym Vegard; Skauli, Torbjørn; Stahl, Annette (2020-01-17)Multispectral imaging is an attractive sensing modality for small unmanned aerial vehicles (UAVs) in numerous applications. The most compact spectral camera architecture is based on spectral filters in the focal plane. ... -
A Performance Characteristic for Net Light Collection in Hyperspectral and Conventional Cameras: A*
Skauli, Torbjørn (2022-12-09)The signal-to-noise ratio of modern cameras under normal operating conditions tends to be limited by “photon noise” originating from the random arrival of photons. For best signal-to-noise ratio, it is desirable to collect ... -
Pixel scaling in infrared focal plane arrays
Catrysse, Peter B.; Skauli, Torbjørn (2013)We discuss effects that arise in pixels of IR focal plane arrays (FPAs) when pixel size scales down to approach the wavelength of the incident radiation. To study these effects, we perform first-principles electromagnetic ... -
Real-time anomaly detection in hyperspectral images using multivariate normal mixture models and GPU processing
Tarabalka, Yulija; Haavardsholm, Trym Vegard; Kåsen, Ingebjørg; Skauli, Torbjørn (2009)Hyperspectral imaging, which records a detailed spectrum of light arriving in each pixel, has many potential uses in remote sensing as well as other application areas. Practical applications will typically require real-time ... -
Sensor noise informed representation of hyperspectral data, with benefits for image storage and processing
Skauli, Torbjørn (2011)Many types of hyperspectral image processing can benefit from knowledge of noise levels in the data, which can be derived from sensor physics. Surprisingly, such information is rarely provided or exploited. Usually, the ... -
Simplified measurement of point spread functions of hyperspectral cameras for assessment of spatial coregistration
Skauli, Torbjørn; Torkildsen, Hans Erling (2019-05-14)In multi- and hyperspectral imaging, spatial coregistration of the point spread functions (PSFs) of all bands within each pixel is critical for the integrity of measured spectra. There is a need to define a standardized ... -
Specifying radiometric performance of hyperspectral and conventional cameras: A minimal set of independent characteristics
Skauli, Torbjørn (2020)The radiometric performance of cameras is customarily characterized and specified in terms of component properties such as F-number and readout noise. This paper considers the camera as an integrated unit and derives ...