Improved image decompression for reduced transform coding artifacts

The perceived quality of images reconstructed from low bit rate compression is severely degraded by the appearance of transform coding artifacts. This paper proposes a method for producing higher quality reconstructed images based on a stochastic model for the image data. Quantization (scalar or vector) partitions the transform coefficient space and maps all points in a partition cell to a representative reconstruction point, usually taken as the centroid of the cell. The proposed image estimation technique selects the reconstruction point within the quantization partition cell which results in a reconstructed image which best fits a non-Gaussian Markov random field (MRF) image model. This approach results in a convex constrained optimization problem which can be solved iteratively. At each iteration, the gradient projection method is used to update the estimate based on the image model. In the transform domain, the resulting coefficient reconstruction points are projected to the particular quantization partition cells defined by the compressed image. Experimental results will be shown for images compressed using scalar quantization of block DCT and using vector quantization of subband wavelet transform. The proposed image decompression provides a reconstructed image with reduced visibility of transform coding artifacts and superior perceived quality

Pennsylvania Folklife Vol. 34, No. 1

• American News in Eighteenth and Nineteenth Century Swiss Almanacs: An Overview • The Stuff of Which Folksongs are Made: Dialect Poetry of Lina Somer (1862-1932) • Word Gain and Loss in the English of the Pennsylvania Germans • The Autograph Album: A Victorian Girl\u27s Best Friend • Cobwebs on My Mind: Untangling Family Relationships • Aldes un Neieshttps://digitalcommons.ursinus.edu/pafolklifemag/1105/thumbnail.jp

Pennsylvania Folklife Vol. 39, No. 2

• The Recovery of the Feminine in an Early American Pietist Community: The Interpretive Challenge of the Theology of Conrad Beissel • A Religious and Geographical History of the Shakers, 1747-1988 • Indiana Amish Family Records • Eel for Christmas: An Italian Tradition • Recollections of Ninety-Two Years • Those Old-Time Children\u27s Days • Aldes un Neies (Old and New)https://digitalcommons.ursinus.edu/pafolklifemag/1126/thumbnail.jp

Pennsylvania Folklife Vol. 42, No. 1

• The Trunk in the Attic was a Window • The Rural Pennsylvania-German Home and Family • The Happy Story of Georges Creek • Duties of a Rural School Board at the Turn of the Century • Aldes un Neies (Old and New)https://digitalcommons.ursinus.edu/pafolklifemag/1135/thumbnail.jp

A Controlled Study on the Characterisation of Bioaerosols Emissions from Compost

Bioaerosol emissions arising from biowaste treatment are an issue of public concern. To better characterise the bioaerosols, and to assess a range of measurement methods, we aerosolised green waste compost under controlled conditions. Viable and non-viable Andersen samplers, cyclone samplers and a real time bioaerosol detection system (Spectral Intensity Bioaerosol Sensor (SIBS)) were deployed simultaneously. The number-weighted fraction of fluorescent particles was in the range 22–26% of all particles for low and high emission scenarios. Overall fluorescence spectral profiles seen by the SIBS exhibited several peaks across the 16 wavelength bands from 298 to 735 nm. The size-fractionated endotoxin profile showed most endotoxin resided in the 2.1–9 μm aerodynamic diameter fraction, though up to 27% was found in a finer size fraction. A range of microorganisms were detected through culture, Matrix Assisted Laser Desorption and Ionisation Time of Flight Mass Spectrometry (MALDI-TOF) and quantitative polymerase chain reaction (qPCR), including Legionella pneumophila serogroup 1. These findings contribute to our knowledge of the physico-chemical and biological characteristics of bioaerosols from composting sites, as well as informing future monitoring approaches and data interpretation for bioaerosol measurement

Pennsylvania Folklife Vol. 30, No. 3

• The Good Life on Grandfather\u27s Farm • The Folklore of Local History • Pennsylvania-Palatinate Informal Folk Cultural Exchanges • Maria Assunta: Berwick\u27s Italian Religious Festival • Aldes un Neies / Old & Newhttps://digitalcommons.ursinus.edu/pafolklifemag/1091/thumbnail.jp

An entangled two photon source using biexciton emission of an asymmetric quantum dot in a cavity

A semiconductor based scheme has been proposed for generating entangled photon pairs from the radiative decay of an electrically-pumped biexciton in a quantum dot. Symmetric dots produce polarisation entanglement, but experimentally-realised asymmetric dots produce photons entangled in both polarisation and frequency. In this work, we investigate the possibility of erasing the `which-path' information contained in the frequencies of the photons produced by asymmetric quantum dots to recover polarisation-entangled photons. We consider a biexciton with non-degenerate intermediate excitonic states in a leaky optical cavity with pairs of degenerate cavity modes close to the non-degenerate exciton transition frequencies. An open quantum system approach is used to compute the polarisation entanglement of the two-photon state after it escapes from the cavity, measured by the visibility of two-photon interference fringes. We explicitly relate the two-photon visibility to the degree of Bell-inequality violation, deriving a threshold at which Bell-inequality violations will be observed. Our results show that an ideal cavity will produce maximally polarisation-entangled photon pairs, and even a non-ideal cavity will produce partially entangled photon pairs capable of violating a Bell-inequality.Comment: 16 pages, 10 figures, submitted to PR

Pennsylvania Folklife Vol. 38, No. 3

• The Wayside Inn • A Draft Board in World War I • The Compass Inn: A Stagecoach Era Legacy • The Pennsylvania German Dialect Playwriting Contests of 1941, 1942, 1983 and 1986 • Aldes un Neies (Old and New)https://digitalcommons.ursinus.edu/pafolklifemag/1123/thumbnail.jp

Spatial Variations of Galaxy Number Counts in the SDSS I.: Extinction, Large-Scale Structure and Photometric Homogeneity

We study the spatial variation of galaxy number counts using five band photometric images from the Sloan Digital Sky Survey. The spatial variation of this sample of 46 million galaxies collected from 2200 sq. degrees can be understood as the combination of Galactic extinction and large-scale clustering. With the use of the reddening map of Schlegel, Finkbeiner & Davis (1998), the standard extinction law is verified for the colour bands from u to z within 5% in the region of small extinction values, E(B-V)<0.15. The residual spatial variations of the number counts suggests that the error of global calibration for SDSS photometry is smaller than 0.02 mag.Comment: Submitted to Astronomical Journa