| 1. |
- Johansson, Ulf, et al.
(author)
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NanoMAX: A hard x-ray nanoprobe beamline at MAX IV
- 2013
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In: X-ray Nanoimaging: Instruments and Methods. - : SPIE. - 1996-756X .- 0277-786X. ; 8851, s. 88510-88510
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Conference paper (peer-reviewed)abstract
- We describe the design of the NanoMAX beamline to be built among the first phase beamlines of the MAX IV facility in Lund, Sweden. NanoMAX will be a hard X-ray imaging beamline providing down to 10 nm in direct spatial resolution, enabling investigations of very small heterogeneous samples exploring methods of diffraction, scattering, absorption, phase contrast and fluorescence. The beamline will have two experimental stations using Fresnel zone plates and Kirkpatrick-Baez mirror optics for beam focusing, respectively. This paper focuses on the optical design of the beamline excluding the experimental stations but also describes general ideas about the endstations and the nano-focusing optics to be used. The NanoMAX beamline is planned to be operational late 2016.
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| 2. |
- Landgren, Matilda, et al.
(author)
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Segmentation of the Left Heart Ventricle in Ultrasound Images Using a Region Based Snake
- 2013
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In: Medical Imaging 2013: Image Processing. - : SPIE. - 1996-756X .- 0277-786X. - 9780819494436 ; 8669
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Conference paper (peer-reviewed)abstract
- Ultrasound imaging of the heart is a non-invasive method widely used for different applications. One of them is to measure the blood volume in the left ventricle at different stages of the heart cycle. This demands a proper segmentation of the left ventricle and a (semi-) automated method would decrease intra-variability as well as workload. This paper presents a semi-automated segmentation method that uses a region based snake. To avoid any unwanted concavities in the segmentations due to the cardiac valve we use two anchor points in the snake that are located to the left and to the right of the cardiac valve respectively. For the possibility of segmentations in different stages of the heart cycle these anchor points are tracked through the cycle. This tracking is based both on the resemblance of a region around the anchor points and a prior model of the movement in the y-direction of the anchor points. The region based snake functional is the sum of two terms, a regularizing term and a data term. It is our data term that is region based since it involves the integration of a two-dimensional subdomain of the image plane. A segmentation of the left ventricle is obtained by minimizing the functional which is done by continuously reshaping the contour until the optimal shape and size is obtained. The developed method shows promising results.
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| 3. |
- Lundin, Patrik, et al.
(author)
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Passive unmanned sky spectroscopy for remote bird classification
- 2011
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In: Remote Sensing For Agriculture, Ecosystems, And Hydrology XIII. - : SPIE. - 0277-786X .- 1996-756X. ; 8174
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Conference paper (peer-reviewed)abstract
- We present a method based on passive spectroscopy with aim to remotely study flying birds. A compact spectrometer is continuously recording spectra of a small section of the sky, waiting for birds to obscure part of the field-of-view when they pass the field in flight. In such situations the total light intensity received through the telescope, looking straight up, will change very rapidly as compared to the otherwise slowly varying sky light. On passage of a bird, both the total intensity and the spectral shape of the captured light changes notably. A camera aimed in the same direction as the telescope, although with a wider field-of-view, is triggered by the sudden intensity changes in the spectrometer to record additional information, which may be used for studies of migration and orientation. Example results from a trial are presented and discussed. The study is meant to explore the information that could be gathered and extracted with the help of a spectrometer connected to a telescope. Information regarding the color, size and height of flying birds is discussed. Specifically, an application for passive distance determination utilizing the atmospheric oxygen A-band absorption at around 760 nm is discussed.
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| 4. |
- Ginis, Vincent, et al.
(author)
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Transforming optical forces
- 2013
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In: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE. - 0277-786X .- 1996-756X. - 9780819496560 ; 8806, s. 880603-
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Conference paper (peer-reviewed)abstract
- We show how transformation optics can enhance optical gradient forces between two optical waveguides by several orders of magnitude. The technique is based on a coordinate transformation that alters the perceived distance between the waveguides. This transformation can be implemented using single-negative metamaterial thin films. The process is remarkably robust to the dissipative loss normally observed in metamaterials. Therefore, our results provide an alternative way to enhance optical forces in nanophotonic actuation systems and may be combined with existing resonator-based enhancement methods to produce optical gradient forces with unprecedented amplitude.
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| 5. |
- Johannesson-Andersson, Kerstin
(author)
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On image sensor dynamic range utilized by security cameras
- 2012
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In: Sensors, Cameras, and Systems for Industrial and Scientific Applications XIII. - : SPIE. - 1996-756X .- 0277-786X. ; 8298
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Conference paper (peer-reviewed)abstract
- The dynamic range is an important quantity used to describe an image sensor. Wide/High/Extended dynamic range is often brought forward as an important feature to compare one device to another. The dynamic range of an image sensor is normally given as a single number, which is often insufficient since a single number will not fully describe the dynamic capabilities of the sensor. A camera is ideally based on a sensor that can cope with the dynamic range of the scene. Otherwise it has to sacrifice some part of the available data. For a security camera the latter may be critical since important objects might be hidden in the sacrificed part of the scene. In this paper we compare the dynamic capabilities of some image sensors utilizing a visual tool. The comparison is based on the use case, common in surveillance, where low contrast objects may appear in any part of a scene that through its uneven illumination, span a high dynamic range. The investigation is based on real sensor data that has been measured in our lab and a synthetic test scene is used to mimic the low contrast objects. With this technique it is possible to compare sensors with different intrinsic dynamic properties as well as some capture techniques used to create an effect of increased dynamic range.
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| 6. |
- Eldada, L. A., et al.
(author)
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Introduction
- 2014
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In: Proceedings of SPIE, the International Society for Optical Engineering. - : SPIE. - 0277-786X .- 1996-756X. ; 8989, s. IX-X
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Journal article (peer-reviewed)
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| 7. |
- Gierl, Christian, et al.
(author)
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Tuneable VCSEL aiming for the application in interconnects and short haul systems
- 2011
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In: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE. - 0277-786X .- 1996-756X. - 9780819484963 ; 7959
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Conference paper (other academic/artistic)abstract
- Widely tunable vertical cavity surface emitting lasers (VCSEL) are of high interest for optical communications, gas spectroscopy and fiber-Bragg-grating measurements. In this paper we present tunable VCSEL operating at wavelength around 850 nm and 1550 nm with tuning ranges up to 20 nm and 76 nm respectively. The first versions of VCSEL operating at 1550 nm with 76 nm tuning range and an output power of 1.3mW were not designed for high speed modulation, but for applications where only stable continious tuning is essential (e.g. gas sensing). The next step was the design of non tunable VCSEL showing high speed modulation frequencies of 10 GHz with side mode supression ratios beyond 50 dB. The latest version of these devices show record output powers of 6.7mW at 20 °C and 3mW at 80 °C. The emphasis of our present and future work lies on the combination of both technologies. The tunable VCSEL operating in the 850 nm-region reaches a modulation bandwidth of 5.5GHz with an output power of 0.8mW.
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| 8. |
- Glasse, A., et al.
(author)
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The throughput and sensitivity of the JWST mid-infrared instrument
- 2010
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In: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE. - 0277-786X .- 1996-756X. - 9780819482211 ; 7731
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Conference paper (other academic/artistic)abstract
- The Verification Model (VM) of MIRI has recently completed an extensive programme of cryogenic testing, with the Flight Model (FM) now being assembled and made ready to begin performance testing in the next few months. By combining those VM test results which relate to MIRI's scientific performance with measurements made on FM components and sub-assemblies, we have been able to refine and develop the existing model of the instrument's throughput and sensitivity. We present the main components of the model, its correlation with the existing test results and its predictions for MIRI's performance on orbit. © 2010 SPIE.
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| 9. |
- Hamngren Blomqvist, Charlotte, 1984, et al.
(author)
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Design and evaluation of a microfluidic system for inhibition studies of yeast cell signaling
- 2012
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In: Proceedings of SPIE. - : SPIE. - 0277-786X .- 1996-756X. - 9780819491756 ; , s. 84582K-
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Conference paper (peer-reviewed)abstract
- In cell signaling, different perturbations lead to different responses and using traditional biological techniques that result in averaged data may obscure important cell-to-cell variations. The aim of this study was to develop and evaluate a four-inlet microfluidic system that enables single-cell analysis by investigating the effect on Hog1 localization post a selective Hog1 inhibitor treatment during osmotic stress. Optical tweezers was used to position yeast cells in an array of desired size and density inside the microfluidic system. By changing the flow rates through the inlet channels, controlled and rapid introduction of two different perturbations over the cell array was enabled. The placement of the cells was determined by diffusion rates flow simulations. The system was evaluated by monitoring the subcellular localization of a fluorescently tagged kinase of the yeast "High Osmolarity Glycerol" (HOG) pathway, Hog1-GFP. By sequential treatment of the yeast cells with a selective Hog1 kinase inhibitor and sorbitol, the subcellular localization of Hog1-GFP was analysed on a single-cell level. The results showed impaired Hog1-GFP nuclear localization, providing evidence of a congenial design. The setup made it possible to remove and add an agent within 2 seconds, which is valuable for investigating the dynamic signal transduction pathways and cannot be done using traditional methods. We are confident that the features of the four-inlet microfluidic system will be a valuable tool and hence contribute significantly to unravel the mechanisms of the HOG pathway and similar dynamic signal transduction pathways.
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| 10. |
- Isaksson, Oscar, et al.
(author)
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Manipulation of optically levitated particles
- 2013
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In: Proceedings of SPIE, Proc. SPIE 8810, Optical Trapping and Optical Micromanipulation X. - : SPIE. - 0277-786X .- 1996-756X. - 9780819496607 ; 8810:article nr 88100O
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Conference paper (peer-reviewed)abstract
- The development of an experimental system in which optical levitation combined with Millikans classical oil drop experiment will be presented. The focus of the apparatus is a glass cell (25x72x25 mm3) in which an oil drop is levitated using a vertically aligned laser beam. A laser power of about 0.9 W is needed to capture a drop, whereas typically 0.3 W is sufficient to maintain it in the trap. An alternating electric field is applied vertically across the cell, causing the drop to oscillate in the vertical direction. The amplitude of the oscillations depends on the strength of the electric field and the q/m ratio of the oil drop. The oscillations are observed by imaging scattered laser light onto either a screen or a position sensitive detector. The number of discrete charges on the drop can be reduced by exposing it to either UV-light or a radioactive source. The radius of the drop is measured by detecting the diffraction pattern produced when illuminated with a horizontally aligned He-Ne laser beam. The mass of the drop can then be determined since the density of the oil is known. Hence, absolute measurements of both the mass and the charge of the drop can be obtained. The goal of the experiment is to design a system which can be used to demonstrate several fundamental physical phenomena using the bare eye as the only detector. The experimental set-up will be further developed for studies of light scattering and spectroscopy of liquids and for studies of interactions between liquid drops. © 2013 SPIE.
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