Showing papers in "Signal Processing in 1981"

TL;DR: The approximation problem for high-order minimum phase FIR filter is solved without requiring any polynomial factorization, using a modified Parks-McClellan program and the FFT algorithm.

TL;DR: In this paper, the interference between the modes can be utilized to estimate range and depth of an acoustic source in shallow water by applying high resolution power estimators to a hydrophone array.

TL;DR: This paper evaluates the error performance of radix-4 FFT algorithms (the input quantization error and the coefficient inaccuracy is not considered), and assumes fixed-point two's complement arithmetic.

TL;DR: In this paper, a new method for representation of speech spectra based on a pole-zero decomposition technique is proposed, where the parameters of a pole zero model for the smoothed short-time spectrum of speech are determined by adopting a cepstral matching criterion.

TL;DR: In this article, a signal processing method for enhancing the directional separation of an ordinary (dummy-head) stereo speech recording is described that, after initial adaptation to a certain direction, simulates the human ability to concentrate on speech coming from this direction and to suppress disturbing speakers from other directions.

TL;DR: A modified autocorrelation method of linear prediction is proposed for pitch-synchronous analysis of voiced speech that guarantees the stability of the estimated all-pole filter and is shown to perform better than the covariance and autcorrelation methods of linear Prediction.

TL;DR: Given an elongated object in a digital image, a thinning transform is described to simultaneously calculate the coordinates of its medial line elements and a value for these elements equal to the width of the object at the element's coordinates.

TL;DR: In this article, a mathematical representation of the processing performed by the peripheral nervous cells of the human visual system is given, which consists essentially of a set of shift-variant convolutions, implying non-uniform resolutions in both the space and frequency domains.

TL;DR: In this article, the frequency and time domain characteristics of two "multi-rate" filter banks, a pure DFT, realized by an FFT processor, and a combination of a special polyphase network with the FFT are reported on.

TL;DR: In this article, a deterministic approach towards the analysis of coefficient errors in DFT and FFT was proposed, and detailed results were presented in a compact "necessary wordlength for prescribed criteria and output accuracy" form.

TL;DR: In this paper, it is shown that the derivative of an appropriately modified version of the phase modulation of a line exists, is continuous and can therefore be defined as an instantaneous frequency, and that the modulation functions can be estimated using complex demodulation.

TL;DR: The first one is an improved version of Freeman's procedure, and in the second one the area is computed as the sum of the lengths of discrete chords.

TL;DR: Fast State-Space IIR Decimators (FSSD) as mentioned in this paper have been proposed for high-order IIR output-decimating state-space digital filters (SSDFs).

TL;DR: In this paper, a novel approach to the design of recursive polyphase networks with application to multirate filtering and digital filter banks is proposed, where all zeros of the polyphase network are located on the z-plane unit circle and all poles are single, corresponding to an optimum magnitude response with minimum phase.

TL;DR: Several alternative architectures for image processing are discussed, some current hardware development projects in the USA are described, and new emerging architectures, which are still in the development stage, are discussed.

TL;DR: The algorithm correctly fills every kind of closed digital curve, no matter of its thickness, of the presence of “repeating” or “brush-past” arcs and of the simply or multiply connectedness of the contoured regions.

TL;DR: In this article, starting from a polar representation of the density function, the authors present some closed form formulas, which can be successfully used in the reconstruction of images, and some numerical tests are also presented.

TL;DR: In this article, the maximum entropy spectral analysis (MESA) technique is applied to signals with spectral peaks of finite width and the Burg and Least Squares algorithms are used.

TL;DR: This paper presents three functional demarcations of pitch estimation methods based on the linear model of speech production, analysis of the short-time spectrum and examination of the time domain signal as used for speech processing and shows that evaluation and comparison of different algorithms becomes consistent and easy within each demarcation.

TL;DR: In this article, the performance of an envelope detector receiver for tone detection applications is evaluated in terms of probability of false alarm and probability of correct detection as functions of the receiver type, signal and noise parameters.

TL;DR: In this article, the authors proposed a nearly-optimum signal for communication theory with the product of pulse duration and spectral width, referred to the positive frequency spectrum only, is 1.1814.

TL;DR: These spectral windows provide a significant means of high-resolution low-leakage over-shoot-free computationally-efficient discrete-time-data and discrete-image smoothing and are sufficient for most applications.

TL;DR: In this article, the authors deal with the formant features of the speech signals for nasal /n/, /m/ and liquid /l/, /r/ sounds in CV (consonant-vowel) syllables.

TL;DR: An extremely simple device for the calculation of the Walsh Discrete Transform of a function which is delta modulated is presented, allowing the Transform to be calculated with very simple hardware and making the demodulation unnecessary.

TL;DR: A set of geometrical phantoms with different patterns of cold lesions to obtain LROC curves in different cases was simulated to evaluate the lesion detectability of a program implemented on a minicomputer system to indicate possible defects on liver scans.

TL;DR: A non-linear space-variant operator is proposed, in order to separate the two additive components of an image: the background which includes the main transitions of the scene and the difference signal which contains details and texture information of the picture.

TL;DR: It is shown that the sequential algorithm greatly reduces estimation error with the same average expenditure of the signal beam energy, although the reduction is obtained only in the case of shot-noise-limited estimation.

TL;DR: A very compact digital signal procesor is described, which has a specialized architecture for computing some signal processing algorithms and a simple microprogram control is used that works with a clock rate of 10 MHz.

TL;DR: The main features of the system are capability of processing irregularly distributed data points; interactive facility during the editing and map refinement steps; modular organization; use of minicomputer systems with standard display devices.

TL;DR: Results of experiments with computer recognition of handwritten Hebrew characters are presented and the features used for the classification were the number of line crossings along some specified intersections, and the relative lengths of horizontal and vertical segments.