Search

Large commercial of the shelf pixel arrays in current remote sensing instruments used in CubeSats make on-board processing increasingly important and enables data improvement. Therefore, we first consider the individual steps of the adapted bad pixel detection algorithm - ISMFD. In particular, we consider pixel-to-pixel variations and temporal flickering of pixels in commercial of the shelf sCMOS imaging sensors. We were able to detect an increase of bad pixels from (2.05±0.01)% to (4.1±0.1)% using real measurement images of the flying remote sensing instrument AtmoSHINE. A preliminary implemented adaptive on-board binning method was able to achieve a constant signal-to-noise-ratio on an image with a dynamic light intensity. The additional consideration of bad pixels in the binning method could demonstrate the achievement of data quality of the future remote sensing instrument AtmoLITE.

PURPOSE: The iKnife is a new surgical tool designed to aid in tumor resection procedures by providing enriched chemical feedback about the tumor resection cavity from electrosurgical vapors. We build and compare machine learning classifiers that are capable of distinguishing primary cancer from surrounding tissue at different stages of tumor progression. In developing our classification framework, we implement feature reduction and recognition tools that will assist in the translation of xenograft studies to clinical application and compare these tools to standard linear methods that have been previously demonstrated. METHODS: Two cohorts (n=6 each) of 12 week old female immunocompromised (Rag2−/−;Il2rg−/−) mice were injected with the same human breast adenocarcinoma (MDA-MB-231) cell line. At 4 and 6 weeks after cell injection, mice in each cohort were respectively euthanized, followed by iKnife burns performed on tumors and tissues prior to sample collection for future studies. A feature reduction technique that uses a neural network is compared to traditional linear analysis. For each method, we fit a classifier to distinguish primary cancer from surrounding tissue. RESULTS: Both classifiers can distinguish primary cancer from metastasis and surrounding tissue. The classifier that uses a neural network achieves an accuracy of 96.8% and the classifier without the neural network achieves an accuracy of 96%. CONCLUSIONS: The performance of these classifiers indicate that this device has the potential to offer real-time, intraoperative classification of tissue. This technology may be used to assist in intraoperative margin detection and inform surgical decisions to offer a better standard of care for cancer patients.

A novel CubeSat payload for atmospheric research has been developed to study the temperature distribution in the mesosphere and lower thermosphere region. The payload consists of a small interferometer for the observation of airglow at 762 nm. Since the rotational structure of the O2 A-band emission follows the Boltzmann law, the ratio of different emission lines allows for temperature retrieval without the need of a precise absolute radiometric calibration of the instrument. Integrated in a 6U CubeSat, the instrument will perform simultaneous limb measurements between 60 km and 150 km globally. The agility of a CubeSat shall be used to focus the measurements on specific regions from different viewing directions. In order to achieve high spectral resolution and high optical throughput, a spatial heterodyne interferometer was chosen for detecting the rotational structure of the O2 A-band emission. The utilization of a two-dimensional imaging detector allows for recording these interferograms at various altitudes at the same time. Since this instrument type has no moving parts, it can be built as a solid block which makes it very attractive for atmospheric measurements especially from space. For highly spatially resolved images of the atmosphere in limb view mode, a high-quality front optics, which images the scene onto the refraction gratings of the interferometer, is required. In addition, a detector optics with minimal aberrations is needed to image the gratings onto the focal plane array. The optical design of the interferometer as well as the technical layout of front and detector optics are presented.

A highly miniaturized limb sounder for the observation of the O2 A-band to derive temperatures in the mesosphere and lower thermosphere is presented. The instrument consists of a monolithic spatial heterodyne spectrometer, which is able to resolve the rotational structure of that band. The SHS operates at a Littrow wavelength of 762 nm with a resolving power in the order of 10.000. Complemented by a front optics with an acceptance angle of less than ±1 degree and a detector optics, the entire optical system fits into a volume of about 1.5 liters. This allows this instrument to be flown on a three or six unit CubeSat. In this paper, we introduce the optical design and computer simulations on the expected performance of the instrument. The laboratory characterization of a prototype instrument, which has been built on university level, and the lessons learned are discussed.

This article presents the characterization and analysis of a commercial off-the-shelf (COTS) CMOS detector utilized in a miniaturized satellite payload for atmospheric temperature measurements. To evaluate the performance of the selected CMOS detector, a series of tests were performed. The temperature dependent dark current, the readout noise and the system gain are determined, which are provided for the subsequent system performance evaluation and data processing. A case study is established to simulate the space radiation effect to determine the needed shielding thickness on the instrument. The effect of radiation damage on the CMOS image sensors is investigated using a Co-60 Gamma radiation source.

The Institute for Atmospheric and Environmental Research at the University of Wuppertal and the Institute of Energy and Climate Research Stratosphere (IEK-7) at the Research Center Juelich developed a novel CubeSat payload for atmospheric research. The payload consists of a small spectrometer for the observation of airglow at 762 nm. The line intensities of the oxygen A-band are used to derive temperatures in the mesosphere and lower thermosphere (MLT) region. The temperature data will be used to analyze dynamical wave structures in the atmosphere which have become increasingly important for the modeling of the climate system. Integrated in a 6U CubeSat, the instrument needs a highly accurate attitude determination and control system (ADCS) for limb sounding of the atmosphere. The agility of a CubeSat shall be used to sweep the line-of-sight through specific regions of interest to derive a three-dimensional image of an atmospheric volume using tomographic reconstruction techniques. The spectrometer technology chosen to measure the ro-vibrational structure of the O2 atmospheric band at 762 nm is a Spatial Heterodyne Interferometer (SHI) originally proposed by Pierre Connes in 1958. The throughput of an SHI is orders of magnitude larger than of a conventional grating spectrometer of the same size. It can be designed to deliver extraordinary spectral resolution to resolve individual emission lines. The utilization of a two-dimensional imaging detector allows for recording interferograms at adjacent locations simultaneously. Since an SHI has no moving parts, it can be built as a monolithic block which makes it very attractive for remote sensing, especially from space.

During its two missions of about one week duration each in November 1994 and in August 1997 the Cryogenic Infrared Spectrometers and Telescopes for the Atmosphere (CRISTA) experiment observed spectrally resolved mid- and far- infrared emissions from the earth limb in the altitude regime from the troposphere to the lower thermosphere. The measurements concentrated on high spatial resolution in all three dimensions in the lower part of the height range. At upper mesosphere/lower thermosphere altitudes global ozone concentrations during day and night, daytime carbon-dioxide densities, and atmospheric temperatures were derived using a comprehensive non-LTE model. The derived parameters compare well with other experimental data. Pronounced horizontal structures in latitude as well as in longitude are found in all parameters showing that dynamical influences are of importance also in the upper mesosphere/lower thermosphere. Carbon dioxide mixing ratios start to depart from their tropospheric values at altitudes as low as 70 - 80 km. Atmospheric temperatures of 140 K and below were retrieved near the mesopause at high northern latitudes in August. These data are supported by the simultaneous observation of polar mesospheric clouds.