6,061 research outputs found
Retrieval of Images Using Color, Shape and Texture Features Based on Content
The current study deals with deriving of image feature descriptor by error diffusion based block truncation coding (EDBTC). The image feature descriptor is basically comprised by the two error diffusion block truncation coding, color quantizers and its equivalent bitmap image. The bitmap image distinguish the image edges and textural information of two color quantizers to signify the color allocation and image contrast derived by the Bit Pattern Feature and Color Co-occurrence Feature. Tentative outcome reveal the benefit of proposed feature descriptor as contrast to existing schemes in image retrieval assignment under normal and textural images. The Error-Diffusion Block Truncation Coding method compresses an image efficiently, and at the same time, its consequent compacted information flow can provides an efficient feature descriptor intended for operating image recovery and categorization. As a result, the proposed design preserves an effective candidate for real-time image retrieval applications
A User Oriented Image Retrieval System using Halftoning BBTC
The objective of this paper is to develop a system for content based image retrieval (CBIR) by accomplishing the benefits of low complexity Ordered Dither Block Truncation Coding based on half toning technique for the generation of image content descriptor. In the encoding step ODBTC compresses an image block into corresponding quantizes and bitmap image. Two image features are proposed to index an image namely co-occurrence features and bitmap patterns which are generated using ODBTC encoded data streams without performing the decoding process. The CCF and BPF of an image are simply derived from the two quantizes and bitmap respectively by including visual codebooks. The proposed system based on block truncation coding image retrieval method is not only convenient for an image compression but it also satisfy the demands of users by offering effective descriptor to index images in CBIR system
ATC: an Advanced Tucker Compression library for multidimensional data
We present ATC, a C++ library for advanced Tucker-based compression of
multidimensional numerical data, based on the sequentially truncated
higher-order singular value decomposition (ST-HOSVD) and bit plane truncation.
Several techniques are proposed to improve compression rate, speed, memory
usage and error control. First, a hybrid truncation scheme is described which
combines Tucker rank truncation and TTHRESH quantization [Ballester-Ripoll et
al., IEEE Trans. Visual. Comput. Graph., 2020]. We derive a novel expression to
approximate the error of truncated Tucker decompositions in the case of core
and factor perturbations. Furthermore, a Householder-reflector-based approach
is proposed to compress the orthogonal Tucker factors. Certain key improvements
to the quantization procedure are also discussed. Moreover, particular
implementation aspects are described, such as ST-HOSVD procedure using only a
single transposition. We also discuss several usability features of ATC,
including the presence of multiple interfaces, extensive data type support and
integrated downsampling of the decompressed data. Numerical results show that
ATC maintains state-of-the-art Tucker compression rates, while providing
average speed-ups of 2.6-3.6 and halving memory usage. Furthermore, our
compressor provides precise error control, only deviating 1.4% from the
requested error on average. Finally, ATC often achieves significantly higher
compression than non-Tucker-based compressors in the high-error domain.Comment: The ATC software is publicly available at the following repository:
https://gitlab.kuleuven.be/u0118878/at
Review of Summation-by-parts schemes for initial-boundary-value problems
High-order finite difference methods are efficient, easy to program, scales
well in multiple dimensions and can be modified locally for various reasons
(such as shock treatment for example). The main drawback have been the
complicated and sometimes even mysterious stability treatment at boundaries and
interfaces required for a stable scheme. The research on summation-by-parts
operators and weak boundary conditions during the last 20 years have removed
this drawback and now reached a mature state. It is now possible to construct
stable and high order accurate multi-block finite difference schemes in a
systematic building-block-like manner. In this paper we will review this
development, point out the main contributions and speculate about the next
lines of research in this area
Analysis of Thisbe and Pyramus functional domains reveals evidence for cleavage of Drosophila FGFs
Background: As important regulators of developmental and adult processes in metazoans, Fibroblast Growth
Factor (FGF) proteins are potent signaling molecules whose activities must be tightly regulated. FGFs are known to
play diverse roles in many processes, including mesoderm induction, branching morphogenesis, organ formation,
wound healing and malignant transformation; yet much more remains to be learned about the mechanisms of
regulation used to control FGF activity.
Results: In this work, we conducted an analysis of the functional domains of two Drosophila proteins, Thisbe (Ths)
and Pyramus (Pyr), which share homology with the FGF8 subfamily of ligands in vertebrates. Ths and Pyr proteins
are secreted from Drosophila Schneider cells (S2) as smaller N-terminal fragments presumably as a result of
intracellular proteolytic cleavage. Cleaved forms of Ths and Pyr can be detected in embryonic extracts as well. The
FGF-domain is contained within the secreted ligand portion, and this domain alone is capable of functioning in
the embryo when ectopically expressed. Through targeted ectopic expression experiments in which we assay the
ability of full-length, truncated, and chimeric proteins to support cell differentiation, we find evidence that (1) the
C-terminal domain of Pyr is retained inside the cell and does not seem to be required for receptor activation and
(2) the C-terminal domain of Ths is secreted and, while also not required for receptor activation, this domain does
plays a role in limiting the activity of Ths when present.
Conclusions: We propose that differential protein processing may account for the previously observed inequalities
in signaling capabilities between Ths and Pyr. While the regulatory mechanisms are likely complex, studies such as
ours conducted in a tractable model system may be able to provide insights into how ligand processing regulates
growth factor activity
- …