The authors outline OCR (optical character recognition) technology developed at AT&T Bell Laboratories, including a recognition network that learns feature extraction kernels and a custom VLSI chip that is designe...
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ISBN:
(纸本)0818621346
The authors outline OCR (optical character recognition) technology developed at AT&T Bell Laboratories, including a recognition network that learns feature extraction kernels and a custom VLSI chip that is designed for neural-net image processing. It is concluded that both high speed and high accuracy can be obtained using neural-net methods for character recognition. Networks can be designed that learn their own feature extraction kernels. Special-purpose neural-net chips combined with digital signal processors can quickly evaluate character-recognition neural nets. This high speed is particularly useful for recognition-based segmentation of character strings.
Detection and thresholding using a stochastic approach is discussed. A general form of detectors which includes a number of well-known detectors as special cases is discussed. Thresholding is indispensable to eliminat...
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Detection and thresholding using a stochastic approach is discussed. A general form of detectors which includes a number of well-known detectors as special cases is discussed. Thresholding is indispensable to eliminate spurious responses from the detection process. The authors propose a weighted thresholding, which is designed to cope with a variety of anomalies. The analysis and experimental results on real images show that intelligent thresholding methods can make a significant difference for discontinuity detection.< >
A locally connected multi-layer stochasticneural network and its associated VLSI array neuroprocessors have been developed for high-performance image flow computing systems. An extendable VLSI neural chip has been de...
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A locally connected multi-layer stochasticneural network and its associated VLSI array neuroprocessors have been developed for high-performance image flow computing systems. An extendable VLSI neural chip has been designed with a silicon area of 4.6*6.8 mm/sup 2/ in a MOSIS 2 mu m scalable CMOS process. The mixed analog-digital design techniques are utilized to achieve compact and programmable synapses with gain-adjustable neurons and winner-take-all cells for massively parallel neural computation. Hardware annealing through the control of the neurons' gain helps to efficiently search the optimal solutions. Computing of image flow using one 2 mu m 72-neuron neural chip can be accelerated by a factor of 187 more than a Sun-4/260 workstation. Real-time image flow processing on industrial images is practical using an extended array of VLSI neural chips. Actual examples on moving trucks are presented.< >
The authors describe a modular neural network system for the removal of impulse noise from the composite video signal of television receivers, and the use of the Princeton Engine multi-processor for real-time performa...
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The authors describe a modular neural network system for the removal of impulse noise from the composite video signal of television receivers, and the use of the Princeton Engine multi-processor for real-time performance assessment. This system out-performs alternative methods, such as median filters and matched filters. The system uses only eight neurons, and can be economically implemented in VLSI.< >
The problem considered is the effective compression of image data. Compared to the many methods which allow for high compression factors (mainly based on the DCT), the proposed neural approaches offer, after a suitabl...
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The problem considered is the effective compression of image data. Compared to the many methods which allow for high compression factors (mainly based on the DCT), the proposed neural approaches offer, after a suitable training, comparable performance both in terms of perceived image quality and measured SNR. Moreover, they are able to perform in the same step the two main required operations of transformation and selection of the most significant terms, with a correspondingly smaller computational effort.< >
A stochasticneural direct adaptive control algorithm for partially known state-space nonlinear time-varying plants is presented. A neural network is used to generate the control signal, which optimizes a quadratic (o...
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A stochasticneural direct adaptive control algorithm for partially known state-space nonlinear time-varying plants is presented. A neural network is used to generate the control signal, which optimizes a quadratic (one-step-ahead prediction) performance index. In comparison to conventional stochastic state-space adaptive control, this neural control algorithm offers higher computation speed due to the parallel processing structure of the neural network. The algorithm is limited to known system matrices B(k) and C(k). For applications where B(k) and C(k) are unknown to the controller, an indirect neural adaptive control scheme may be used.< >
Proposes a neural network based on differential Gabor filters for computing the image flow. The approach attempts to overcome the limitation of the spatio-temporal frequency models by taking time derivatives of the Ga...
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Proposes a neural network based on differential Gabor filters for computing the image flow. The approach attempts to overcome the limitation of the spatio-temporal frequency models by taking time derivatives of the Gabor responses as the carrier of visual motion information. A differential Gabor filter is a linear filter with the spatial derivative of a Gabo elemental function as its impulse response function. The authors derive a rigorous scheme for computing image motion. Based on this computational scheme, they present the architecture of a neural network system for visual motion. The computational model effectively bypasses the certainty constraint that severely limits the accuracy of the spatio-temporal frequency models, and avoids the time dimension integration required by the spatio-temporal frequency models. Experimental results show that the differential Gabor filter model performs better than the existing models.< >
Several texture segmentation algorithms based on deterministic and stochastic relaxation principles, and their implementation on parallel networks, are described. The segmentation process is posed as an optimization p...
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Several texture segmentation algorithms based on deterministic and stochastic relaxation principles, and their implementation on parallel networks, are described. The segmentation process is posed as an optimization problem and two different optimality criteria are considered. The first criterion involves maximizing the posterior distribution of the intensity field given the label field (maximum a posteriori estimate). The posterior distribution of the texture labels is derived by modeling the textures as Gauss Markov random fields (GMRFs) and characterizing the distribution of different texture labels by a discrete multilevel Markov model. A stochastic learning algorithm is proposed. This iterated hill-climbing algorithm combines fast convergence of deterministic relaxation with the sustained exploration of the stochastic algorithms, but is guaranteed to find only a local minimum. The second optimality criterion requires minimizing the expected percentage of misclassification per pixel by maximizing the posterior marginal distribution, and the maximum posterior marginal algorithm is used to obtain the corresponding solution. All these methods implemented on parallel networks can be easily extended for hierarchical segmentation; results of the various schemes in classifying some real textured images are presented.< >
The stochastic relaxation algorithm of S. Geman and D. Geman (IEEE Trans. Pattern Anal. Mach. Intell., vol. PAMI-6, pp. 721-741, 1984), which is based on the Markov random-field (MRF) model of images, was implemented ...
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The stochastic relaxation algorithm of S. Geman and D. Geman (IEEE Trans. Pattern Anal. Mach. Intell., vol. PAMI-6, pp. 721-741, 1984), which is based on the Markov random-field (MRF) model of images, was implemented on a hypercube parallel computer for contour extraction of human face images. The local energy parameters that define the MRF model were estimated by the learning algorithm recently proposed by the authors, while supervised by a desirable object contour as a teaching signal. The constrained optimization method recently developed by D. Geman (imagevision Comput., vol. 5, no. 2, pp. 61-65, 1987) was utilized to avoid flaws in a fast simulated annealing. The contours extracted by the learning stochastic relaxation method were systematically compared with those obtained by several conventional edge detection methods. The contours extracted by the authors' method include few discontinuity points and small amounts of noise, and faithfully represent the contours of the original image. The authors propose a new algorithm, multiple-level, multiple-resolution MRF, which is an extension of the original MRF. This model can incorporate a priori knowledge about the global structures in images and still be implemented in a local and parallel mode.
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