21 research outputs found
Visually lossless compression of digital hologram sequences
Digital hologram sequences have great potential for the recording of 3D scenes of moving macroscopic objects as
their numerical reconstruction can yield a range of perspective views of the scene. Digital holograms inherently
have large information content and lossless coding of holographic data is rather inefficient due to the speckled
nature of the interference fringes they contain.
Lossy coding of still holograms and hologram sequences has shown promising results. By definition, lossy
compression introduces errors in the reconstruction. In all of the previous studies, numerical metrics were used
to measure the compression error and through it, the coding quality. Digital hologram reconstructions are highly
speckled and the speckle pattern is very sensitive to data changes. Hence, numerical quality metrics can be
misleading. For example, for low compression ratios, a numerically significant coding error can have visually
negligible effects. Yet, in several cases, it is of high interest to know how much lossy compression can be achieved,
while maintaining the reconstruction quality at visually lossless levels.
Using an experimental threshold estimation method, the staircase algorithm, we determined the highest
compression ratio that was not perceptible to human observers for objects compressed with Dirac and MPEG-
4 compression methods. This level of compression can be regarded as the point below which compression
is perceptually lossless although physically the compression is lossy. It was found that up to 4 to 7.5 fold
compression can be obtained with the above methods without any perceptible change in the appearance of video
sequences
Command Similarity Measurement Using NLP
Peer reviewe
ANS complex of St John's wort PR-10 protein with 28 copies in the asymmetric unit: a fiendish combination of pseudosymmetry with tetartohedral twinning.
Hyp-1, a pathogenesis-related class 10 (PR-10) protein from St John's wort (Hypericum perforatum), was crystallized in complex with the fluorescent probe 8-anilino-1-naphthalene sulfonate (ANS). The highly pseudosymmetric crystal has 28 unique protein molecules arranged in columns with sevenfold translational noncrystallographic symmetry (tNCS) along c and modulated X-ray diffraction with intensity crests at l = 7n and l = 7n ± 3. The translational NCS is combined with pseudotetragonal rotational NCS. The crystal was a perfect tetartohedral twin, although detection of twinning was severely hindered by the pseudosymmetry. The structure determined at 2.4 Å resolution reveals that the Hyp-1 molecules (packed as β-sheet dimers) have three novel ligand-binding sites (two internal and one in a surface pocket), which was confirmed by solution studies. In addition to 60 Hyp-1-docked ligands, there are 29 interstitial ANS molecules distributed in a pattern that violates the arrangement of the protein molecules and is likely to be the generator of the structural modulation. In particular, whenever the stacked Hyp-1 molecules are found closer together there is an ANS molecule bridging them.Financial support for this project was provided by the
European Union within the European Regional Developmental
Fund and by the Polish Ministry of Science and Higher
Education (grant No. NN 301 003739) and National Science
Center (2013/10/M/NZ1/00251). RJR was supported by a
Principal Research Fellowship from theWellcome Trust (grant
No. 082961/Z/07/Z). ZD was supported in part by the Intramural
Research Program of the National Cancer Institute,
Center for Cancer Research.This is the final published version. It first appeared at http://scripts.iucr.org/cgi-bin/paper?S1399004715001388
3β-Acetoxy-12α-chloro-d-friedooleanan-28,14β-olide
The title compound, C32H49ClO4, was obtained along with nitrile and lactam products in the POCl3-catalysed Beckmann rearrangement from 3β-acetoxy-12-hydroxyiminoolean-28-olic acid methyl ester. The mechanism of the transformation leading to the title compound remains unclear and requires further investigation. Rings A, B and E are in chair conformations, ring C has a twisted-boat conformation, ring D a conformation halfway between boat and twisted-boat and rings D and E are cis-fused. In the crystal, molecules are connected by weak intermolecular C—H⋯O hydrogen bonds into layers extending parallel to the bc plane
Visually lossless compression of digital hologram sequences
Digital hologram sequences have great potential for the recording of 3D scenes of moving macroscopic objects as
their numerical reconstruction can yield a range of perspective views of the scene. Digital holograms inherently
have large information content and lossless coding of holographic data is rather inefficient due to the speckled
nature of the interference fringes they contain.
Lossy coding of still holograms and hologram sequences has shown promising results. By definition, lossy
compression introduces errors in the reconstruction. In all of the previous studies, numerical metrics were used
to measure the compression error and through it, the coding quality. Digital hologram reconstructions are highly
speckled and the speckle pattern is very sensitive to data changes. Hence, numerical quality metrics can be
misleading. For example, for low compression ratios, a numerically significant coding error can have visually
negligible effects. Yet, in several cases, it is of high interest to know how much lossy compression can be achieved,
while maintaining the reconstruction quality at visually lossless levels.
Using an experimental threshold estimation method, the staircase algorithm, we determined the highest
compression ratio that was not perceptible to human observers for objects compressed with Dirac and MPEG-
4 compression methods. This level of compression can be regarded as the point below which compression
is perceptually lossless although physically the compression is lossy. It was found that up to 4 to 7.5 fold
compression can be obtained with the above methods without any perceptible change in the appearance of video
sequences
2-[N-(2,4-Dimethoxyphenyl)acetamido]-1,3-thiazol-4-yl acetate
The title compound, C15H16N2O5S, is a product of the reaction of 2-(2,4-dimethoxyphenylamino)-1,3-thiazol-4(5H)-one with acetic anhydride. The presence of the acetyl and acetoxy groups in the molecule indicates that the starting thiazole exists as a tautomer in the reaction mixture with exocyclic amino and enol moieties. The acetyl group is tilted slightly from the heterocyclic ring plane [dihedral angle = 4.46 (11)°], while the acetoxy group is almost perpendicular to this ring [dihedral angle = 88.14 (12)°]. An intramolecular acetyl–methoxy C—H...O interaction is noted. In the crystal, molecules are connected into a three-dimensional architecture by C—H...O interactions
Displaying digital holograms of real-world objects on a mobile device using tilt-based interaction
Holography is a well-known technique for sensing
and displaying real-world three-dimensional (3D) objects.
Reconstructions from digital holograms are typically displayed with regular two-dimensional (2D) screens and therefore lot of the 3D specific information is not passed on to the viewer during the display process. Mobile devices have interesting possibilities for displaying 3D data interactively. In this study, we show how nine viewers evaluated hologram reconstructions with a tilt based
display system incorporated into a mobile device
Visually lossless compression of digital hologram sequences
Digital hologram sequences have great potential for the recording of 3D scenes of moving macroscopic objects as
their numerical reconstruction can yield a range of perspective views of the scene. Digital holograms inherently
have large information content and lossless coding of holographic data is rather inefficient due to the speckled
nature of the interference fringes they contain.
Lossy coding of still holograms and hologram sequences has shown promising results. By definition, lossy
compression introduces errors in the reconstruction. In all of the previous studies, numerical metrics were used
to measure the compression error and through it, the coding quality. Digital hologram reconstructions are highly
speckled and the speckle pattern is very sensitive to data changes. Hence, numerical quality metrics can be
misleading. For example, for low compression ratios, a numerically significant coding error can have visually
negligible effects. Yet, in several cases, it is of high interest to know how much lossy compression can be achieved,
while maintaining the reconstruction quality at visually lossless levels.
Using an experimental threshold estimation method, the staircase algorithm, we determined the highest
compression ratio that was not perceptible to human observers for objects compressed with Dirac and MPEG-
4 compression methods. This level of compression can be regarded as the point below which compression
is perceptually lossless although physically the compression is lossy. It was found that up to 4 to 7.5 fold
compression can be obtained with the above methods without any perceptible change in the appearance of video
sequences
Visually lossless compression of digital hologram sequences
Digital hologram sequences have great potential for the recording of 3D scenes of moving macroscopic objects as
their numerical reconstruction can yield a range of perspective views of the scene. Digital holograms inherently
have large information content and lossless coding of holographic data is rather inefficient due to the speckled
nature of the interference fringes they contain.
Lossy coding of still holograms and hologram sequences has shown promising results. By definition, lossy
compression introduces errors in the reconstruction. In all of the previous studies, numerical metrics were used
to measure the compression error and through it, the coding quality. Digital hologram reconstructions are highly
speckled and the speckle pattern is very sensitive to data changes. Hence, numerical quality metrics can be
misleading. For example, for low compression ratios, a numerically significant coding error can have visually
negligible effects. Yet, in several cases, it is of high interest to know how much lossy compression can be achieved,
while maintaining the reconstruction quality at visually lossless levels.
Using an experimental threshold estimation method, the staircase algorithm, we determined the highest
compression ratio that was not perceptible to human observers for objects compressed with Dirac and MPEG-
4 compression methods. This level of compression can be regarded as the point below which compression
is perceptually lossless although physically the compression is lossy. It was found that up to 4 to 7.5 fold
compression can be obtained with the above methods without any perceptible change in the appearance of video
sequences