scholarly journals Configuration and Registration of Multi-Camera Spectral Image Database of Icon Paintings

Computation ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 47
Author(s):  
Arash Mirhashemi
Keyword(s):  
Dynamic Range ◽  
Specular Reflection ◽  
Signal To Noise Ratio ◽  
Simulated Data ◽  
Image Database ◽  
High Dynamic Range ◽  
Registration Method ◽  
Spatial Registration ◽  
Feature Based ◽  
The Cost

At the cost of added complexity and time, hyperspectral imaging provides a more accurate measure of the scene’s irradiance compared to an RGB camera. Several camera designs with more than three channels have been proposed to improve the accuracy. The accuracy is often evaluated based on the estimation quality of the spectral data. Currently, such evaluations are carried out with either simulated data or color charts to relax the spatial registration requirement between the images. To overcome this limitation, this article presents an accurately registered image database of six icon paintings captured with five cameras with different number of channels, ranging from three (RGB) to more than a hundred (hyperspectral camera). Icons are challenging topics because they have complex surfaces that reflect light specularly with a high dynamic range. Two contributions are proposed to tackle this challenge. First, an imaging configuration is carefully arranged to control the specular reflection, confine the dynamic range, and provide a consistent signal-to-noise ratio for all the camera channels. Second, a multi-camera, feature-based registration method is proposed with an iterative outlier removal phase that improves the convergence and the accuracy of the process. The method was tested against three other approaches with different features or registration models.

scholarly journals Ab initiostructure determination of nanocrystals of organic pharmaceutical compounds by electron diffraction at room temperature using a Timepix quantum area direct electron detector

2016 ◽  
Vol 72 (2) ◽  
pp. 236-242 ◽  
Author(s):  
E. van Genderen ◽  
M. T. B. Clabbers ◽  
P. P. Das ◽  
A. Stewart ◽  
I. Nederlof ◽  
...  
Keyword(s):  
Electron Diffraction ◽  
Room Temperature ◽  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
Three Dimensional ◽  
Direct Methods ◽  
Liquid Nitrogen Temperature ◽  
High Dynamic Range ◽  
Electron Diffraction Data ◽  
High Signal

Until recently, structure determination by transmission electron microscopy of beam-sensitive three-dimensional nanocrystals required electron diffraction tomography data collection at liquid-nitrogen temperature, in order to reduce radiation damage. Here it is shown that the novel Timepix detector combines a high dynamic range with a very high signal-to-noise ratio and single-electron sensitivity, enablingab initiophasing of beam-sensitive organic compounds. Low-dose electron diffraction data (∼0.013 e− Å−2 s−1) were collected at room temperature with the rotation method. It was ascertained that the data were of sufficient quality for structure solution using direct methods using software developed for X-ray crystallography (XDS,SHELX) and for electron crystallography (ADT3D/PETS,SIR2014).

scholarly journals Methods for Voltage-Sensitive Dye Imaging of Rat Cortical Activity With High Signal-to-Noise Ratio

2007 ◽  
Vol 98 (1) ◽  
pp. 502-512 ◽  
Author(s):  
Michael T. Lippert ◽  
Kentaroh Takagaki ◽  
Weifeng Xu ◽  
Xiaoying Huang ◽  
Jian-Young Wu
Keyword(s):  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
Field Potential ◽  
High Sensitivity ◽  
High Dynamic Range ◽  
High Signal ◽  
Blue Dye ◽  
Voltage Sensitive Dye ◽  
Imaging Device

We describe methods to achieve high sensitivity in voltage-sensitive dye (VSD) imaging from rat barrel and visual cortices in vivo with the use of a blue dye RH1691 and a high dynamic range imaging device (photodiode array). With an improved staining protocol and an off-line procedure to remove pulsation artifact, the sensitivity of VSD recording is comparable with that of local field potential recording from the same location. With this sensitivity, one can record from ∼500 individual detectors, each covering an area of cortical tissue 160 μm in diameter (total imaging field ∼4 mm in diameter) and a temporal resolution of 1,600 frames/s, without multiple-trial averaging. We can record 80–100 trials of intermittent 10-s trials from each imaging field before the VSD signal reduces to one half of its initial amplitude because of bleaching and wash-out. Taken together, the methods described in this report provide a useful tool for visualizing evoked and spontaneous waves from rodent cortex.

scholarly journals Probing the cold magnetised Universe with SPICA-POL (B-BOP)

2019 ◽  
Vol 36 ◽  
Author(s):  
Ph. André ◽  
A. Hughes ◽  
V. Guillet ◽  
F. Boulanger ◽  
A. Bracco ◽  
...  
Keyword(s):  
Magnetic Fields ◽  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
European Space Agency ◽  
Dust Emission ◽  
Far Infrared ◽  
High Dynamic Range ◽  
Wide Field ◽  
Infrared Telescope ◽  
Nearby Galaxies

Abstract Space Infrared Telescope for Cosmology and Astrophysics (SPICA), the cryogenic infrared space telescope recently pre-selected for a ‘Phase A’ concept study as one of the three remaining candidates for European Space Agency (ESA's) fifth medium class (M5) mission, is foreseen to include a far-infrared polarimetric imager [SPICA-POL, now called B-fields with BOlometers and Polarizers (B-BOP)], which would offer a unique opportunity to resolve major issues in our understanding of the nearby, cold magnetised Universe. This paper presents an overview of the main science drivers for B-BOP, including high dynamic range polarimetric imaging of the cold interstellar medium (ISM) in both our Milky Way and nearby galaxies. Thanks to a cooled telescope, B-BOP will deliver wide-field 100–350 $\mu$ m images of linearly polarised dust emission in Stokes Q and U with a resolution, signal-to-noise ratio, and both intensity and spatial dynamic ranges comparable to those achieved by Herschel images of the cold ISM in total intensity (Stokes I). The B-BOP 200 $\mu$ m images will also have a factor $\sim $ 30 higher resolution than Planck polarisation data. This will make B-BOP a unique tool for characterising the statistical properties of the magnetised ISM and probing the role of magnetic fields in the formation and evolution of the interstellar web of dusty molecular filaments giving birth to most stars in our Galaxy. B-BOP will also be a powerful instrument for studying the magnetism of nearby galaxies and testing Galactic dynamo models, constraining the physics of dust grain alignment, informing the problem of the interaction of cosmic rays with molecular clouds, tracing magnetic fields in the inner layers of protoplanetary disks, and monitoring accretion bursts in embedded protostars.

A theoretical study of digital silicon photomultiplier utilization in diffuse optical imaging systems

2019 ◽  
Vol 64 (3) ◽  
pp. 357-363 ◽  
Author(s):  
Taha Haddadifam ◽  
Mohammad Azim Karami
Keyword(s):  
Optical Imaging ◽  
Continuous Wave ◽  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
High Sensitivity ◽  
High Dynamic Range ◽  
Diffuse Optical Imaging ◽  
Silicon Photomultiplier ◽  
Thoracic Imaging ◽  
Low Level

Abstract Digital silicon photomultiplier (dSiPM) is introduced for diffuse optical imaging (DOI) applications instead of conventional photomultiplier tubes and avalanche photodiodes (APDs) as a state-of-the-art detector. According to the low-level light regime in DOI applications, high sensitivity and high dynamic range (DR) image sensors are needed for DOI systems. dSiPM is proposed as a developing detector which can detect low-level lights. Also, an accurate equation is obtained for calculating the DR of dSiPMs. Different dSiPMs and the corresponding benefits are studied for DOI applications. Furthermore, a 120 dB DR dSiPM is chosen for use in DOI systems. It is shown that dSiPMs can be utilized in DOI configurations such as time domain (TD), frequency domain (FD) and continuous wave (CW) systems. Ultimately, by utilizing dSiPM in DOI systems, the DOI method can be used for thoracic imaging due to the high DR and signal-to-noise ratio (SNR) of the detector.

scholarly journals Using DSLR to 'Scan' Colour Slides: learning from the Digitising Jemdet Nasr 1988–1989 Project

2020 ◽  
Author(s):  
Mónica Palmero Fernández
Keyword(s):  
Dynamic Range ◽  
Cost Effective ◽  
Archaeological Site ◽  
High Dynamic Range ◽  
Photographic Film ◽  
Film Scanner ◽  
Cost Effective Method ◽  
High Dynamic ◽  
University Department ◽  
The Cost

This article presents a cost-effective method for digitising photographic film for archival purposes using a DSLR camera, focussing on the widely used colour reversal Kodachrome film produced by Eastman Kodak between 1935 and 2009. I discuss the digitisation of an archive of 787 Kodachrome slides taken between 1988 and 1989 during the excavation of Jemdet Nasr, an archaeological site located in southern Iraq (Project website). I compare results obtained using a film scanner (Nikon Coolscan IV ED) with two different scanning software solutions (SilverFast and VueScan), a flatbed scanner (HP Scanjet 8300), and two DSLR cameras with macro lens (a Canon EOS KissX3 with 105mm lens and a Canon EOS 80D with 90mm lens). The results demonstrate the cost-effective value of the DSLR method for archives where time and resources are limited, but where digital photography equipment might be readily available, such as an archaeological unit or a university department. The method allows for high quality, fast and economical digitisation of excavation and collection archives that will enhance research. The method also offers superior results in rendering the high dynamic range of photographic film such as Kodachrome.

scholarly journals HLS Based Approach to Develop an Implementable HDR Algorithm

Electronics ◽  
2018 ◽  
Vol 7 (11) ◽  
pp. 332 ◽  
Author(s):  
Rappy Saha ◽  
Partha Banik ◽  
Ki-Doo Kim
Keyword(s):  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
Simple Algorithm ◽  
Structural Similarity ◽  
High Dynamic Range ◽  
Field Programmable ◽  
Hardware Description ◽  
On Chip ◽  
High Level ◽  
Removal Technique

Hardware suitability of an algorithm can only be verified when the algorithm is actually implemented in the hardware. By hardware, we indicate system on chip (SoC) where both processor and field-programmable gate array (FPGA) are available. Our goal is to develop a simple algorithm that can be implemented on hardware where high-level synthesis (HLS) will reduce the tiresome work of manual hardware description language (HDL) optimization. We propose an algorithm to achieve high dynamic range (HDR) image from a single low dynamic range (LDR) image. We use highlight removal technique for this purpose. Our target is to develop parameter free simple algorithm that can be easily implemented on hardware. For this purpose, we use statistical information of the image. While software development is verified with state of the art, the HLS approach confirms that the proposed algorithm is implementable to hardware. The performance of the algorithm is measured using four no-reference metrics. According to the measurement of the structural similarity (SSIM) index metric and peak signal-to-noise ratio (PSNR), hardware simulated output is at least 98.87 percent and 39.90 dB similar to the software simulated output. Our approach is novel and effective in the development of hardware implementable HDR algorithm from a single LDR image using the HLS tool.

A signal-to-noise ratio comparison of high dynamic range CMOS image sensors

2009 ◽  
Author(s):  
Leo H. C. Braga ◽  
Suzana Domingues ◽  
José G. Gomes ◽  
Antonio C. Mesquita
Keyword(s):  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
High Dynamic Range ◽  
Image Sensors ◽  
Signal To Noise ◽  
Cmos Image Sensors ◽  
High Dynamic ◽  
Noise Ratio

A Least-Squares Strain Estimator for Elastography

1997 ◽  
Vol 19 (3) ◽  
pp. 195-208 ◽  
Author(s):  
Faouzi Kallel ◽  
Jonathan Ophir
Keyword(s):  
Least Squares ◽  
Spatial Resolution ◽  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
Simulated Data ◽  
Signal To Noise ◽  
Noise Ratio ◽  
Gel Phantom

A least-squares strain estimator (LSQSE) for elastography is proposed. It is shown that with such an estimator, the signal-to-noise ratio in an elastogram ( SNRe) is significantly improved. This improvement is illustrated theoretically using a modified strain filter and experimentally using a homogeneous gel phantom. It is demonstrated that the LSQSE results in an increase of the elastographic sensitivity (smallest strain that could be detected), thereby increasing the strain dynamic range. Using simulated data, it is shown that a tradeoff exists between the improvement in SNRe and the reduction of strain contrast and spatial resolution.

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