15084916
Computing the channel capacity and rate-distortion function with two-sided state information
In this correspondence, we present iterative algorithms that numerically compute the capacity-power and rate-distortion functions for coding with two-sided state information. Numerical examples are provided to demonstrate efficiency of our algorithms.
9060129
Extended Depth-of-Field Microscope Imaging: MPP Image Fusion VS. WAVEFRONT CODING
Biomedical specimens thicker than the microscope depth-of-field (DOF) produces images of limited quality where a part of the specimen is in focus and others out of focus. Even the best in-focus image always contains objects that are blurred. These blurred contents make the quantitative and accurate analysis of the specimen difficult. The problem can be remedied by extending the DOF of the imaging system. One way to achieve this is to apply digital image fusion, a software technique that combines multiple images into a carefully synthesized image. Another way, albeit more expensive, is to incorporate modification in the optical system. In this paper we describe an extended DOF method that is based on multiscale pointwise product (MPP) image fusion, and compare it with the state-of-the-art wavefront coding technique which involves optical modification. We show competitive performance of our method and contrast its pros and cons with those of the wavefront coding.
20227157
Trellis coded color quantization of images
We examine color quantization of images using trellis coded quantization (TCQ). Together with a simple dithering scheme, an 8-bit trellis coded color quantizer reproduces images that are visually indistinguishable from the 24-bit originals. The proposed algorithm can be viewed as a predictive trellis coded color quantization scheme. It is universal in the sense that no training or lookup table is needed. The complexity of TCQ is linear with respect to image size, making trellis coded color quantization suitable for interactive graphics and a window-based display environment.
18292356
On dualities in multiterminal coding problems
It has been shown recently that under certain conditions there exist dualities between different multiterminal (MT) source and channel coding problems. Following these results, we study lossless MT source coding and deterministic MT channel coding problems and point out different dualities between them. In particular, we show that there exists a functional duality between a Slepian-Wolf (SW) coding problem and a deterministic broadcast channel (DBC) coding problem and between a lossless multiple-description (MD) coding problem and a deterministic multiple-access channel (DMAC) coding problem. In analogy to the duality established between DBC and DMAC coding problems, we further propose a similar duality between SW and lossless MD coding problems; in this way, we form a closed "duality loop" of four MT coding problems, which imposes the existence of a single common rate point in the achievable rate regions of all four dual problems. We also consider duality in zero-error MT coding and shed light on practical code design with an example. Finally, extension to the case with only one lossless/deterministic component in the source/channel coding problem is provided.
928702
Non-ubiquitous digital watermarking for record indexing and integrity protection of medical images
Two novel non-ubiquitous digital watermarking schemes are proposed and evaluated in parallel (one in the spatial domain and one in the wavelet domain) for the purpose of record indexing and integrity protection of medical images. A fingerprint of the regions of interest (ROI) in a medical image is generated using the MD5 message-digest algorithm [R. Rivest, April 1992], and it is embedded along with the medical record information into the non-ROI parts of the image. Our experiments show that with both schemes, a payload of 420 bits of information can be achieved watermarking clinical cytogenetic images, without affecting image content in the ROI nor incurring perceptible differences between original and watermarked images. Furthermore, the resulting watermarked images can survive common image processing operations such as cropping, JPEG compression, sharpening, and their combinations.
206577228
Fast Trellis-Coded Color Quantization of Images
We examine color quantization of images using trellis-coded quantization (TCQ) in both the RGB domain and YUV domain. Together with a simple dithering scheme, an eight-bit trellis-coded color quantizer reproduces images that are visually indistinguishable from the 24-bit originals. It can be viewed as a predictive trellis-coded color quantization scheme. We also study trellis-coded vector quantization (TCVQ) for color quantization. Our proposed TCQ-based color quantization schemes are universal in the sense that no training or look-up table is needed. The complexity of TCQ is linear with respect to image size, making trellis-coded color quantization suitable for color printing, real-time interactive graphics and window-based display environment.
1344352
Quality meshing for polyhedra with small angles
We present an algorithm to compute a Delaunay mesh conforming to a polyhedron possibly with small input angles. The radius-edge ratio ofmost output tetrahedra are bounded by a constant, except possibly those that are provably close to small angles. Further, the mesh is graded, that is, edge lengths are at least a constant fraction of the local feature sizes at the edge endpoints. Unlike a previous algorithm, this algorithm is simple to implement as it avoids computing local feature sizes and protective zones explicitly. Our experimental results confirm our claims and show that few skinny tetrahedra remain.
15145046
A novel approach to diagnose diabetes based on the fractal characteristics of retinal images
A novel diagnostic scheme to develop quantitative indexes of diabetes is introduced in this paper. The fractal dimension of the vascular distribution is estimated because we discovered that the fractal dimension of a severe diabetic patient's retinal vascular distribution appears greater than that of a normal human's. The issue of how to yield an accurate fractal dimension is to use high-quality images. To achieve a better image-processing result, an appropriate image-processing algorithm is adopted in this paper. Another important fractal feature introduced in this paper is the measure of lacunarity, which describes the characteristics of fractals that have the same fractal dimension but different appearances. For those vascular distributions in the same fractal dimension, further classification can be made using the degree of lacunarity. In addition to the image-processing technique, the resolution of original image is also discussed here. In this paper, the influence of the image resolution upon the fractal dimension is explored. We found that a low-resolution image cannot yield an accurate fractal dimension. Therefore, an approach for examining the lower bound of image resolution is also proposed in this paper. As for the classification of diagnosis results, four different approaches are compared to achieve higher accuracy. In this study, the fractal dimension and the measure of lacunarity have shown their significance in the classification of diabetes and are adequate for use as quantitative indexes.
359856
Curve reconstruction from noisy samples
We present an algorithm to reconstruct a collection of disjoint smooth closed curves from n noisy samples. Our noise model assumes that the samples are obtained by first drawing points on the curves according to a locally uniform distribution followed by a uniform perturbation of each point in the normal direction with a magnitude smaller than the minimum local feature size. The reconstruction is faithful with a probability that approaches 1 as n increases.We expect that our approach can lead to provable algorithms under less restrictive noise models and for handling non-smooth features.
15245491
Efficient Expected-Case Algorithms for Planar Point Location
Planar point location is among the most fundamental search problems in computational geometry. Although this problem has been heavily studied from the perspective of worst-case query time, there has been surprisingly little theoretical work on expected-case query time. 
 
We are given an n-vertex planar polygonal subdivision S satisfying some weak assumptions (satisfied, for example, by all convex subdivisions). 
 
We are to preprocess this into a data structure so that queries can be answered efficiently. We assume that the two coordinates of each query point are generated independently by a probability distribution also satisfying some weak assumptions (satisfied, for example, by the uniform distribution). 
 
In the decision tree model of computation, it is well-known from information theory that a lower bound on the expected number of comparisons is entropy(S). We provide two data structures, one of size O(n2) that can answer queries in 2 entropy(S) + O(1) expected number of comparisons, and another of size O(n) that can answer queries in (4 + O(1/√log n)) entropy(S)+O(1) expected number of comparisons. These structures can be built in O(n2) and O(n log n) time respectively. Our results are based on a recent result due to Arya and Fu, which bounds the entropy of overlaid subdivisions.
29681392
Schedulability-oriented replication of periodic tasks in distributed real-time systems
We consider the schedulability-oriented replication problem of a set of periodic real-time tasks where each task can be decomposed into several modules and intermodule communications. The objective is to find an allocation in which there exists a feasible schedule for the given task set. In this paper, we adopt a communication model where the replication of modules is not for the sake of fault tolerance but for increasing the degree of schedulability. To solve the problem, we develop a replication technique and embed the technique in a simulated annealing algorithm. Experimental results show that such replication may lead to a higher degree of schedulability and obtain a feasible solution.