A parallel algorithm for generating chain code of objects in binary images

This paper addresses parallel execution of chain code generation on a linear array architecture. The contours in the proposed algorithm are viewed as a set of edges (or contour segments) that can be traced by a top-down contour tracing method to generate the chain codes for the outer and inner object contours. A parallel algorithm that contains the chain code generating rules and operations needed is also described, and the algorithm is mapped onto a one-dimensional systolic array containing processing elements (PEs) to devise this architecture. The architecture extracts the contours of objects and quickly generates the corresponding chain codes after the image data in all rows are inputted in a linear fashion. The total processing time for generating the chain codes in an N×N image is O(3N). By doing so, the real-time requirement is fulfilled and its execution time is independent of the image content. In addition, a partition method is developed to process an image when the parallel architecture has a fixed number of PEs; say two or more. The total execution time for an N×N image by employing a fixed number of PEs is N(N+1)/M+2(M−1), when M is the fixed number of PEs.     

Robust algorithm for tunnel closing in 3D volumetric objects based on topological characteristics of points

In this letter, we propose a robust, linear in time modification of Aktouf, Bertrand and Perroton’s algorithm for tunnel (3D hole) closing in 3D volumetric objects. Our algorithm is insensitive to small distortions and branches. The algorithm has been tested on various 3D images including very complicated 3D crack propagation images. The results of the tests, discussion of the algorithm properties and future research plans are also included in the paper.     

A motion compensated lifting wavelet codec for 3D video coding

A motion compensated lifting (MCLIFT) ramework for the 3D wavelet video coding is proposed in this paper,By using bi-directional motion compensation in each lifting step of the temporal direction,the video frames are effectively de-correlated,With the proper entropy coding and bit-stream packaging schemes,the MCLIFT wavelet video coder is scalable at frame rate and quality level .Experimental results show that the MCLIFT video coder outperforms the 3D wavelet video coder without motion by an average of 0.9-1.3dB,and outperforms MPEG-4 coder by an average of 0.2-0.6dB.     

A class of quasi-cyclic LDPC codes from B_2 （mod m） sequences

A new class of binary low-density parity-check (LDPC) codes is proposed based on B 2 (mod m) sequences.The parity-check matrix of such a code has a column weight of three and a row weight of an arbitrary integer,and a quasi-cyclic structure.The parity-check matrix also has a girth at least 8,and corresponds to a code with minimal distance at least 12.When m is prime, an 8-cycles reduction method is presented to completely avoid the two types of 8-cycles within the total four types existed in the Tanner grap...     

A new method for representing and matching shapes of natural objects

A new method for the representation and comparison of irregular two-dimensional shapes is presented. This method uses a polar transformation of the contour points about the geometric centre of the object. The distinctive vertices of the shape are extracted and used as comparative parameters to minimize the difference of contour distance from the centre. Experiments are performed, more than 39 000 comparisons of database shapes, provided by Sebastian et al. (ICCV (2001) 755), are made and the results are compared to those obtained therein. In addition, 450 comparisons of leaf shape are made and leaves of very similar shape are accurately distinguished. The method is shown to be invariant to translation, rotation and scaling and highly accurate in shape distinction. The method shows more tolerance to scale variation than that of Sebastian et al. (ICCV (2001) 755) and is less computationally intense.     

A C-tree decomposition algorithm for 2D and 3D geometric constraint solving

In this paper, we propose a method which can be used to decompose a 2D or 3D constraint problem into a C-tree. With this decomposition, a geometric constraint problem can be reduced into basic merge patterns, which are the smallest problems we need to solve in order to solve the original problem in certain sense. Based on the C-tree decomposition algorithm, we implemented a software package MMP/Geometer. Experimental results show that MMP/Geometer finds the smallest decomposition for all the testing examples efficiently.     

Automated cell analysis in 2D and 3D: A comparative study

Optical projection tomographic microscopy is a technique that allows 3D analysis of individual cells. Theoretically, 3D morphometry would more accurately capture cellular features than 2D morphometry. To evaluate this thesis, classifiers based on 3D reconstructions of cell nuclei were compared with 2D images from the same nuclei. Human adenocarcinoma and normal lung epithelium cells were used. Testing demonstrated a three-fold reduction in the false negative rate for adenocarcinoma detection in 3D versus 2D at the same high specificity. We conclude that 3D imaging will potentially expand the horizon for automated cell analysis with broad applications in the biological sciences.     

2D到3D图像颜色空间层转换技术研究及实现

从3D相关技术入手,初步讨论了人类视觉及相关转换技术。接着重点描述基于3d红蓝立体原理的图像转换原理,从图像颜色空间角度,着重讨论2D转3D的相关技术及研究现状,并基于电视类节目图像给出一套完整系统设计及实现,并给出相应的实验结果。     

A network algorithm for 3D/2D IPTV distribution using WiMAX and WLAN technologies

The appearance of new broadband wireless technologies jointly with the ability to offer enough quality of service to provide IPTV over them, have made possible the mobility and ubiquity of any type of device to access the IPTV network. The minimum bandwidth required in the access network to provide appropriate quality 3D/2D IPTV services jointly with the need to guarantee the Quality of Experience (QoE) to the end user, makes the need of algorithms that should be able to combine different wireless standards and technologies. In this paper, we propose a network algorithm that manages the IPTV access network and decides which type of wireless technology the customers should connect with when using multiband devices, depending on the requirements of the IPTV client device, the available networks, and some network parameters (such as the number of loss packets and packet delay), to provide the maximum QoE to the customer. The measurements taken in a real environment from several wireless networks allow us to know the performance of the proposed system when it selects each one of them. The measurements taken from a test bench demonstrate the success of our system.     

A 2-point algorithm for 3D reconstruction of horizontal lines from a single omni-directional image

Reconstruction of 3D scenes with abundant straight line features has many applications in computer vision and robot navigation. Most approaches to this problem involve stereo techniques, in which a solution to the correspondence problem between at least two different images is required. In contrast, 3D reconstruction of straight horizontal lines from a single 2D omni-directional image is studied in this paper. The authors show that, for symmetric non-central catadioptric systems, a 3D horizontal line can be estimated using only two points extracted from a single image of the line. One of the two points is the symmetry point of the image curve of horizontal line, and the other is a generic point on the image curve. This paper improves on several prior works, including horizontal line detection in omni-directional image and line reconstruction from four viewing rays, but is simpler than those methods while being more robust. We evaluate how the precision of feature point extraction can affect line reconstruction accuracy, and discuss preliminary experimental results.     

A data embedding scheme for color images based on genetic algorithm and absolute moment block truncation coding

Recently, embedding a large amount of secret data into gray-level and color images with low distortion has become an important research issue in steganography. In this paper, we propose a data embedding scheme by using a well-known genetic algorithm, block truncation code and modification direction techniques to embed secret data into compression codes of color images to expand the variety of cover media. In the scheme, the common bitmap generation procedure of GA-AMBTC has been modified to speed up the hiding procedure. Two embedding strategies are proposed to hide secret data into the common bitmap and the quantization values in each block of the cover image. Experimental results confirm that the proposed scheme can provide high data capacity with acceptable image quality of the stego-images. Moreover, the compression ratio of the scheme is exactly the same as that of GA-AMBTC so that attackers cannot detect any trace of hidden data from the size of the modified compressed result.     

A mosaicing approach for the acquisition and representation of 3D painted surfaces for conservation and restoration purposes

This paper describes an approach to the acquisition and representation of information on 3D painted surfaces (usually frescoes) based on the tassellation and mosaicing of the whole surface. The acquisition is carried out using an active vision system specifically designed for these purposes. In this paper, particular emphasis is placed on the mosaicing procedure of the acquired images, which, while conceptually simple, allows one to obtain very good results thanks to the effective exploitation of the features of the acquisition system. A careful qualitative and quantitative analysis of the performances of the system, obtained through tests on real scenes in the laboratory, is also presented.Received: 28 May 2001, Accepted: 8 November 2002, Published online: 18 June 2003 Correspondence to: Paolo GrattoniMassimiliano Spertino: With I.R.I.T.I. under grant N.202.12484 of the Italian Safeguard of Cultural Heritage C.N.R. project.     

A system for quantifying facial symmetry from 3D contour maps based on transfer learning and fast R-CNN

The Journal of Supercomputing - Physicians spend much time observing the facial symmetry of patients and collecting various data to arrive at an accurate clinical judgment. This study presents a...     

Combining the ant system algorithm and simulated annealing for 3D/2D fixed-outline floorplanning

Three dimensional integrated circuits (3D ICs) can alleviate the problem of interconnection, a critical problem in the nanoscale era, and are also promising for heterogeneous integration. This paper proposes a two-phase method combining the ant system algorithm (AS) and simulated annealing (SA) to handle 3D IC floorplanning with fixed-outline constraints. In the first AS phase, the floorplans are constructed by sequentially packing the block one by one, and the AS is used to explore the appropriate packing order and device layer assignment for the blocks. When packing a block, a proper position including the coordinates and the appropriate layer in the partially constructed floorplan should be chosen from all possible positions. While packing the blocks, a probability layer assignment strategy is proposed to determine the device layer assignment of unpacked blocks. After the AS phase, the SA phase is used to perform further optimization. The proposed method can also be easily applied to 2D floorplanning problems. Compared with the state of the art 3D/2D fixed-outline floorplanner, the experimental results demonstrate the effectiveness of the proposed method.     

A cell-transverse display algorithm for regular and rectilinear 3D grid data

This paper proposes an efficient direct imaging algorithm for constructing iso-surfaces from regular and rectilinear 3D grid data in scientific and engineering visualization. The basic idea is to generate and draw polygons simultaneously by processing the cells spanned by grids in decreasing order of distance from the current viewpoint. Iso-surfaces are generated in five or six tetrahedrons into which the cells are subdivided, and are sent to a graphics device or drawn into a frame buffer on the fly. The execution order of each of the tetrahedrons is identical and is determined by the current viewpoint. Since the algorithm does not need to store intermediate polyhedral data and does not require a depth buffer memory for hidden surface removal, it is applicable to a large quantity of data on a 3D grid, such as computed tomography (CT) data. It is also particularly powerful for semi-transparent display, because transparency calculation can be reduced to image compositing operations if the polygons are drawn in order of their z-depth from the current viewpoint.     

A Simplified Model for Generating 3D Realistic Sound in the Multimedia and Virtual Reality Systems

It is a key feature to embed 3D realistic sound effect in the future multimedia and virtual reality systems.Recent research on acoustics and psychoacoustics reveals the important cues for sound localization and sound perception.One promising approach to generate 3D realistic sound effect uses two earphones by simulating the sound waveforms from sound source to eardrum.This paper summarizes two methods for generating 3D realistic sound and points out their inherent drawbacks.To overcome these drawbacks we propose a simplified model to generate 3D realistic sound at any positions in the horizontal plane based on the results of sound perception and localization.Experimental results show that the model is correct and efficient.     

A differential-geometric approach for 2D and 3D object grasping and manipulation

This article presents an expository work on a differential-geometric treatment of fundamental problems of 2D and 3D object grasping and manipulation by a pair of robot fingers with multi-joints under holonomic or nonholonomic constraints. First, Lagrange’s equation of motion of a fingers-object system whose motion is confined to a vertical plane is derived under holonomic constraints when rolling contacts between finger-ends and object surfaces are permitted. Then, a class of control signals called “blind grasping” and constructed without knowing the object kinematics or using any external sensing like vision or tactile sensation is shown to realize stable object grasping in a dynamic sense. Stability of motion and its convergence to an equibrium manifold are treated on the basis of differential geometry of solution trajectories of the closed-loop dynamics on the constraint manifolds. Second, a mathematical model of 3D object grasping and manipulation by a pair of multi-joint robot fingers is derived under the assumption that spinning motion of rotation around the opposing axis between contact points does no more arise. It is shown that, differently from the 2D case, the instantaneous axis of rotation of the object is time-varying, which induces a nonholonomic constraint expressed as a linear differential equation of rotational motion of the pinched object. It is shown that there is a class of control signals constructed without knowing the object kinematics or using external sensings that can realize “blind grasping” in a dynamic sense. Finally, it is shown that the proposed differential geometric treatment of stability can naturally cope with redundancy resolution problems of surplus degrees-of-freedom (d.f.) of the overall fingers-object system, which is closely related to Bernstein’s d.f. problem.     

A matching algorithm between precursory 3D process model and 2D working procedure drawing based on subgraph isomorphism

To meet the urgent requirement of enterprises for three-dimensional (3D) process models, an approach based on subgraph isomorphism is proposed to solve the matching problem between precursory 3D process model and 2D working procedure drawings. First, the projection drawings of the precursory 3D process model are obtained, then the primitives are extracted and the attributed adjacency graph (AAG) is constructed. Finally, by taking the 2D working procedure drawing as the AAG, and the projection drawing as the...