7,065 research outputs found
Characterization of color cross-talk of CCD detectors and its influence in multispectral quantitative phase imaging
Multi-spectral quantitative phase imaging (QPI) is an emerging imaging
modality for wavelength dependent studies of several biological and industrial
specimens. Simultaneous multi-spectral QPI is generally performed with color
CCD cameras. However, color CCD cameras are suffered from the color crosstalk
issue, which needed to be explored. Here, we present a new approach for
accurately measuring the color crosstalk of 2D area detectors, without needing
prior information about camera specifications. Color crosstalk of two different
cameras commonly used in QPI, single chip CCD (1-CCD) and three chip CCD
(3-CCD), is systematically studied and compared using compact interference
microscopy. The influence of color crosstalk on the fringe width and the
visibility of the monochromatic constituents corresponding to three color
channels of white light interferogram are studied both through simulations and
experiments. It is observed that presence of color crosstalk changes the fringe
width and visibility over the imaging field of view. This leads to an unwanted
non-uniform background error in the multi-spectral phase imaging of the
specimens. It is demonstrated that the color crosstalk of the detector is the
key limiting factor for phase measurement accuracy of simultaneous
multi-spectral QPI systems.Comment: 16 pages, 8 figure
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Spectral imaging in preclinical research and clinical pathology.
Spectral imaging methods are attracting increased interest from researchers and practitioners in basic science, pre-clinical and clinical arenas. A combination of better labeling reagents and better optics creates opportunities to detect and measure multiple parameters at the molecular and cellular level. These tools can provide valuable insights into the basic mechanisms of life, and yield diagnostic and prognostic information for clinical applications. There are many multispectral technologies available, each with its own advantages and limitations. This chapter will present an overview of the rationale for spectral imaging, and discuss the hardware, software and sample labeling strategies that can optimize its usefulness in clinical settings
Studies of a Lacustrine-Volcanic Mars Analog Field Site with Mars-2020-like Instruments
On the upcoming Marsâ2020 rover two remote sensing instruments, MastcamâZ and SuperCam, and two microscopic proximity science instruments, SHERLOC and PIXL, will collect compositional (mineralogy, chemistry, and organics) data essential for paleoenvironmental reconstruction. The synergies between and limitations of these instruments were evaluated via study of a Mars analog field site in the Mojave Desert, using instruments approximating the data that will be returned by Marsâ2020. A ground truth dataset was generated for comparison to validate the results. The site consists of a succession of clayârich mudstones of lacustrine origin, interbedded tuffs, a carbonateâsilica travertine deposit, and gypsiferous mudstone strata. The major geological units were mapped successfully using simulated Marsâ2020 data. Simulated MastcamâZ data identified unit boundaries and Feâbearing weathering products. Simulated SuperCam passive shortwave infrared and green Raman data were essential in identifying major mineralogical composition and changes in lacustrine facies at distance; this was possible even with spectrally downsampled passive IR data. LIBS and simulated PIXL data discriminated and mapped major element chemistry. Simulated PIXL revealed mmâscale zones enriched in zirconium, of interest for age dating. SHERLOCâlike data mapped sulfate and carbonate at subâmm scale; silicates were identified with increased laser pulses/spot or by averaging of hundreds of spectra. Fluorescence scans detected and mapped varied classes of organics in all samples, characterized further with followâon spatially targeted deepâUV Raman spectra. Development of dedicated organics spectral libraries is needed to aid interpretation. Given these observations, the important units in the outcrop would be sampled and cached for sample return
Last generation instrument for agriculture multispectral data collection
In recent years, the acquisition and analysis of multispectral data are gaining a growing interest and importance in agriculture. On the other hand, new technologies are opening up for the possibility of developing and implementing sensors with relatively small size and featuring high technical performances. Thanks to low weights and high signal to noise ratios, such sensors can be transported by different type of means (terrestrial as well as aerial vehicles), giving new opportunities for assessment and monitoring of several crops at different growing stages or health conditions. The choice and specialization of individual bands within the electromagnetic spectrum ranging from the ultraviolet to the infrared, plays a fundamental role in the definition of the so-called vegetation indices (eg. NDVI, GNDVI, SAVI, and dozens of others), posing new questions and challenges in their effective implementation. The present paper firstly discusses the needs of low-distance based sensors for indices calculation, then focuses on development of a new multispectral instrument specially developed for agricultural multispectral analysis. Such instrument features high frequency and high resolution imaging through nine different sensors (1 RGB and 8 monochromes with relative band-pass filters, covering the 390 to 950 nm range). The instrument allows synchronized multiband imaging thanks to integrated global shutter technology, with a frame rate up to 5 Hz; exposure time can be as low as 1/5000 s. An applicative case study is eventually reported on an area featuring different materials (organic and non-organic), to show the new instrument potential.
Last generation instrument for agriculture multispectral data collection. Available from: https://www.researchgate.net/publication/317596952_Last_generation_instrument_for_agriculture_multispectral_data_collection [accessed Jul 11, 2017]
Infrared imaging spectroscopy of skin cancer lesions
Skin cancer is a disease of the twenty-first century since, unfortunately, being tan is associated to be healthy and good looking. UV radiation produces one of the most aggressive kinds of skin cancer: melanoma; once the damage is done there is no other solution that a rapid and effective diagnosis. Clinical examination and biopsies have shown to be slow and costly in many ways, so the possibility of getting a non-invasive optical detection of skin melanomas became a hot topic in biophotonics. In this context, multispectral imaging systems have approached the problem, but none of them worked inside the infrared range. Hence, this work has been proposed as an interesting, long-term project to further investigate about the possibilities of infrared imaging spectroscopy for the early detection of skin cancer through the development of such a system based on an InGaAs camera
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