In this paper, we present a method for registering images of complex 3-D surfaces that does not require explicit correspondences between features across the images. Our method relies on the use of a full 3-D model of ...
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ISBN:
(纸本)0818658258
In this paper, we present a method for registering images of complex 3-D surfaces that does not require explicit correspondences between features across the images. Our method relies on the use of a full 3-D model of the surface to adjust the position and orientation of the camera by minimizing an objective function based on the projections of the images onto the model. This approach constrains the camera parameters strongly enough so that the models do not need, initially, to be accurate to yield good results. When registration has been achieved, the models can be refined and the fine details recovered. Our method is applicable to the calibration of stereo imagery, the precise registration of new images of a scene and the tracking of deformable objects. It can therefore lead to important applications in fields such as augmented reality in a medical context or data compression for transmission purposes. We demonstrate its applicability by using images of faces and of terrain.
Segmentation of blood vessels and extraction of their centerlines in 3D angiography are essential to diagnosis and prognosis of vascular diseases, and advanced imageprocessing.and analysis. In this paper we propose a...
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ISBN:
(纸本)9781424423392
Segmentation of blood vessels and extraction of their centerlines in 3D angiography are essential to diagnosis and prognosis of vascular diseases, and advanced imageprocessing.and analysis. In this paper we propose a semiautomatic method to perform those two tasks simultaneously. A user supplies two end points to the algorithm and a vessel centerline between the two given points is extracted automatically. Local vessel widths are estimated as byproducts. Additional anchor points can be added in between to handle difficult situation. Our method is based upon a polygonal line algorithm. This algorithm is used to find principal curves, nonlinear generalization of principal components, from point clouds. We discuss an application of principal curve to vessel extraction from a theoretical viewpoint. A novel algorithm is then proposed for the application. No data interpolation is needed in the algorithm and centerlines extracted are adaptive to the vasculature complexity on account of their nonparametric representation. We have tested the method on two synthetic data sets and two clinical data sets. Results show that it has high robustness to variation in image resolution, voxel anisotropy and noise. Moreover centerlines obtained are in subvoxel precision and local widths estimated are accurate under limit of image resolution.
A typical digital signal processor (DSP) uses hierarchical memory to handle the trade-off between cost and speed. It has a fast on-chip memory with data-access rates similar to the DSP's processing.rate but it is ...
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ISBN:
(纸本)9780769549903
A typical digital signal processor (DSP) uses hierarchical memory to handle the trade-off between cost and speed. It has a fast on-chip memory with data-access rates similar to the DSP's processing.rate but it is not large enough to hold the entire image data. image buffers typically reside in the larger external memory like DDR whose data access rate is similar to 4-6X slower than the processor rate. Cache or direct memory access (DMA) mechanisms are used to improve the slow access rate of external memory using the internal memory. Optimizing an embedded processing.application to be efficient for such hierarchical memory systems requires block-based algorithm design. This is usually accomplished by manually re-designing the code. This effort requires several man months and DSP expertise. In this paper, we automate this process and demonstrate a performance improvement of similar to 2-4X over conventional frame level processing. We believe that the proposed solution is novel in the sense that it is fully automated and scalable to any memory size and speed. We use a compiler assisted parser to extract the relevant function parameters and use them to re-target the code to be block-based and handle memory management automatically. This is an offline code generation process with self-verification. We have implemented and tested the parser for Texas Instruments (TI) C6000 DSPs but the method is generic to work with any processor core.
One of the main tasks in content-based image retrieval (CBIR) is to reduce the gap between low-level visual features and high-level human concepts. This paper presents a new semi-supervised EM algorithm (NSS-EM), wher...
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One of the main tasks in content-based image retrieval (CBIR) is to reduce the gap between low-level visual features and high-level human concepts. This paper presents a new semi-supervised EM algorithm (NSS-EM), where the image distribution in feature space is modeled as a mixture of Gaussian densities. Due to the statistical mechanism of accumulating and processing.meta knowledge, the NSS-EM algorithm with long-term learning of mixture model parameters can deal,with the cases where users may mislabel images during relevance feedback. Our approach that integrates mixture model of the data, relevance feedback and long-term learning helps to improve retrieval performance. The concept learning is incrementally refined with increased retrieval experiences. Experiment results on Corel database show the efficacy of our proposed concept learning approach.
A system is described which has the ability to highly encode graphics data relating to computer generated animation. The system relies on the fact that in any sequence of animation, a great deal of data is replicated ...
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A system is described which has the ability to highly encode graphics data relating to computer generated animation. The system relies on the fact that in any sequence of animation, a great deal of data is replicated from frame to frame and that through the use of motion and change cues, such scenes can be segmented to highly encode it for transmission to a satellite display system. A simple animated sequence is presented which demonstrates the efficiency of such a data reduction scheme. Further, it is shown that were the sample sequence made more complex, that an even greater data reduction rate would be achieved. Finally, data is shown which compares network generation of simple animated sequences to the stand-alone generation and display of the same set of frames.
The recent increase in popularity of binary feature descriptors has opened the door to new lightweight computer vision applications. Most research efforts thus far have been dedicated to the introduction of new large-...
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ISBN:
(纸本)9781509014378
The recent increase in popularity of binary feature descriptors has opened the door to new lightweight computer vision applications. Most research efforts thus far have been dedicated to the introduction of new large-scale binary features, which are primarily used for keypoint description and matching. In this paper, we show that the side products of small-scale binary feature computations can efficiently filter images and estimate image gradients. The improved efficiency of low-level operations can be especially useful in time-constrained applications. Through our experiments, we show that efficient binary feature convolutions can be used to mimic various imageprocessing.operations, and even outperform Sobel gradient estimation in the edge detection problem, both in terms of speed and F-Measure.
recognition of three dimensional objects independent of size, position and orientation is an important and difficult problem of scene analysis. The use of three dimensional moment invariants is proposed as a solution....
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recognition of three dimensional objects independent of size, position and orientation is an important and difficult problem of scene analysis. The use of three dimensional moment invariants is proposed as a solution. The generalization of the results of two dimensional moment invariants which had linked two dimensional moment invariants to binary quantics is done by linking three dimensional moments to ternary quantics. The existence and number of n**t**h order moments in two and three dimensions is explored. Algebraic invariants of several ternary forms under different orthogonal transformations are derived by using the invariant property of the coefficients of ternary forms. The result is a set of three dimensional moment invariants which are invariant under size, orientation and position change.
Sequences of pictures of growing colonies of animal cells or microorganisms contain information useful to biologists. Special lighting increases the information contained in the pictures and decreases the difficulty o...
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Sequences of pictures of growing colonies of animal cells or microorganisms contain information useful to biologists. Special lighting increases the information contained in the pictures and decreases the difficulty of the image analysis. A high resolution flying spot scanner digitizes images of petri dishes recorded on film. Nonlinear edge region detectors and a region growing algorithm find the outlines of the colonies. Outlines which pass tests for validity are analyzed to extract further information. Data files of parameters are created which are analyzed by programs written by biologists. Statistical and other techniques were used to classify species and locate mutant colonies.
Object location in computed tomography images is a preliminary step required for many automated measurements which may be useful in many diagnostic procedures. Most object location, imageprocessing.techniques are eit...
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Object location in computed tomography images is a preliminary step required for many automated measurements which may be useful in many diagnostic procedures. Most object location, imageprocessing.techniques are either globally based such as histogram segmentation or locally based such as edge detection. The method described uses both local and global information for object location. The technique has been applied to the location of suspected tumors in CT lung and brain images. Sorting and merging steps are required for eliminating noise regions but all suspected tumor regions have been located. Measurements such as boundary roughness or density statistics may also be made on the objects and used to further identify suspicious regions for further study by the radiologists.
Because of the increasing demand for cytogenetic analysis, machine assisted karyotyping of human chromosomes is almost a necessity. One of the most important phases in chromosome analysis and other related histo- or c...
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Because of the increasing demand for cytogenetic analysis, machine assisted karyotyping of human chromosomes is almost a necessity. One of the most important phases in chromosome analysis and other related histo- or cytochemistry work is the scanning of microscopic slides to detect suitable metaphases or cells. In this paper such a system is described based on the use of microprocessors, a digitally controlled microscope, and video hardware for autofocus, thresholding and feature extraction. A hierarchically structured search procedure has excellent results at a scanning speed of 0. 5 cm**2/min.
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