Scene-based method for spatial misregistration detection in hyperspectral imagery

Hyperspectral imaging (HSI) sensors suffer from spatial misregistration, an artifact that prevents the accurate acquisition of the spectra. Physical considerations let us assume that the influence of the spatial misregistration on the acquired data depends both on the wavelength and on the across-track position. A scene-based method, based on edge detection, is therefore proposed. Such a procedure measures the variation on the spatial location of an edge between its various monochromatic projections, giving an estimation for spatial misregistration, and also allowing identification of misalignments. The method has been applied to several hyperspectral sensors, either prism, or grating-based designs. The results confirm the dependence assumptions on lambda and theta, spectral wavelength and across-track pixel, respectively. Suggestions are also given to correct for spatial misregistration.     

Guiding the evolution of product-line configurations

Software and Systems Modeling - A product line is an approach for systematically managing configuration options of customizable systems, usually by means of features. Products are generated for...     

Noise contributions for imaging spectrometers

In the past decade imaging spectrometers for observation of the Earth were developed to use the complete information of a spectrum as a major tool in the study of physical and biological processes of the Earth. Instead of a few relatively broad spectral bands (line detector), this imager concept provides for the detection of many contiguous narrow spectral bands by applying the technology of matrix detectors. The change from one-dimensional to two-dimensional solid-state imagers makes it necessary to carry out the specific signal-to-noise ratio (SNR) analysis of such detectors. A simulation of maximum and minimum radiances for typical spectral signatures of the Earth (water, vegetation) and the verification of these radiances with modular optoelectronic scanner data provide the means for calculation of electrons generated at the matrix detector. For a hypothetical sensor, water-minimum and vegetation-maximum signals are calculated, and the degradation of the SNR caused by image smear of two-dimensional solid-state imagers is demonstrated.     

Do claim factors predict health care utilization after transport accidents?

Background

Injured people who are involved in compensation processes have less recovery and less well-being compared to those not involved in claims settlement procedures. This study investigated whether claim factors, such as no-fault versus common law claims, the number of independent medical assessments, and legal disputes, predict health care utilization after transport accidents.

Method

The sample consisted of 68,911 claimants who lodged a compensation claim at the Transport Accident Commission (TAC) in Victoria, Australia, between 2000 and 2005. The main outcome measure was health care utilization, which was defined as the number of visits to health care providers (e.g. general practitioners, physiotherapists, psychologists) during the 5 year period post-accident.

Results

After correction for gender, age, role in accident, injury type, and severity of injury, it was found that independent medical assessments were associated with greater health care utilization (β = .36, p < .001). Involvement in common law claims and legal disputes were both significantly related to health care utilization (respectively β = .05, p < .001 and β = −.02, p < .001), however, the standardized betas were negligible, therefore the effect is not clinically relevant. A model including claim factors predicted the number of health care visits significantly better (ΔR² = .08, p < .001) than a model including only gender, age, role in accident, injury type, and severity of injury.

Conclusion

The positive association between the number of independent medical assessments and health care utilization after transport accidents may imply that numerous medical assessments have a negative effect on claimants’ health. However, further research is needed to determine a causal relationship.     

Spatial PSF Nonuniformity Effects in Airborne Pushbroom Imaging Spectrometry Data

Efficient and accurate imaging spectroscopy data processing asks for perfectly consistent (i.e., ideally uniform) data in both the spectral and spatial dimensions. However, real pushbroom-type imaging spectrometers are affected by various point spread function (PSF) nonuniformity artifacts. First, individual pixels or lines may be missing in the raw data due to bad pixels originating from the detector, readout errors, or even electronic failures. Second, so-called smile and keystone optical aberrations are inherent to imaging spectrometers. Appropriate resampling strategies are required for the preprocessing of such data if emphasis is put on spatial PSF uniformity. So far, nearest neighbor interpolations have been often recommended and used for resampling. This paper shall analyze the radiometric effects if linear interpolation is used to optimize the spatial PSF uniformity. For modeling interpolation effects, an extensive library of measured surface reflectance spectra as well as real imaging spectroscopy data over various land cover types are used. The real measurements are systematically replaced by interpolated values, and the deviation between original and resampled spectra is taken as a quality measure. The effects of nearest neighbor resampling and linear interpolation methods are compared. It is found that linear interpolation methods lead to average radiometric errors below 2% for the correction of spatial PSF nonuniformity in the subpixel domain, whereas the replacement of missing pixels leads to average errors in the range of 10%-20%     

The spectral database SPECCHIO for improved long-term usability and data sharing

The organised storage of spectral data described by metadata is important for long-term use and data sharing with other scientists. Metadata describing the sampling environment, geometry and measurement process serves to evaluate the suitability of existing data sets for new applications. There is a need for spectral databases that serve as repositories for spectral field campaign and reference signatures, including appropriate metadata parameters. Such systems must be (a) highly automated in order to encourage users entering their spectral data collections and (b) provide flexible data retrieval mechanisms based on subspace projections in metadata spaces.The recently redesigned SPECCHIO system stores spectral and metadata in a relational database based on a non-redundant data model and offers efficient data import, automated metadata generation, editing and retrieval via a Java application.RSL is disseminating the database and software to the remote sensing community in order to foster the use and further development of spectral databases.     

Fermented foods in a global age: East meets West

Fermented foods and alcoholic beverages have long been an important part of the human diet in nearly every culture on every continent. These foods are often well‐preserved and serve as stable and significant sources of proteins, vitamins, minerals, and other nutrients. Despite these common features, however, many differences exist with respect to substrates and products and the types of microbes involved in the manufacture of fermented foods and beverages produced globally. In this review, we describe these differences and consider the influence of geography and industrialization on fermented foods manufacture. Whereas fermented foods produced in Europe, North America, Australia, and New Zealand usually depend on defined starter cultures, those made in Asia and Africa often rely on spontaneous fermentation. Likewise, in developing countries, fermented foods are not often commercially produced on an industrial scale. Although many fermented products rely on autochthonous microbes present in the raw material, for other products, the introduction of starter culture technology has led to greater consistency, safety, and quality. The diversity and function of microbes present in a wide range of fermented foods can now be examined in detail using molecular and other omic approaches. The nutritional value of fermented foods is now well‐appreciated, especially in resource‐poor regions where yoghurt and other fermented foods can improve public health and provide opportunities for economic development. Manufacturers of fermented foods, whether small or large, should follow Good Manufacturing Practices and have sustainable development goals. Ultimately, preferences for fermented foods and beverages depend on dietary habits of consumers, as well as regional agricultural conditions and availability of resources.