Showing papers on "Concatenation published in 1981"

Continuous speech recognition

Abstract: An improved speech recognition method and apparatus for recognizing keywords in a continuous audio signal are disclosed. The keywords, generally either a word or a string of words, are each represented by an element template defined by a plurality of target patterns. Each target pattern is represented by a plurality of statistics describing the expected behavior of a group of spectra selected from plural short-term spectra generated by processing of the incoming audio. The incoming audio spectra are processed to enhance the separation between the spectral pattern classes during later analysis. The processed audio spectra are grouped into multi-frame spectral patterns and are compared, using likelihood statistics, with the target patterns of the element templates. Each multi-frame pattern is forced to contribute to each of a plurality of pattern scores as represented by the element templates. The method and apparatus use speaker independent word models during the training stage to generate, automatically, improved target patterns. The apparatus and method further employ grammatical syntax during the training stage for identifying the beginning and ending boundaries of unknown keywords. Recognition is further improved by use of a plurality of templates representing "silence" or non-speech signals, for example, hum. Also, memory and computation load is reduced by use of modified (collapsed or folded) syntax flow graph logic, implemented by additional (augment) control numbers. A concatenation technique is employed, using dynamic programming techniques, to determine the correct identity of the word string.

Method and apparatus for continuous word string recognition

Abstract: A speech recognition method and apparatus for recognizing word strings in a continuous audio signal are disclosed. The word strings are made up of a plurality of elements, and each element, generally a word, is represented by an element template defined by a plurality of target patterns. Each target pattern is represented by a plurality of statistics describing the expected behavior of a group of spectra selected from plural short-term spectra generated by processing of the incoming audio. Each target pattern has associated therewith at least one required dwell time position and at least one optional dwell time position. The number of required dwell time positions and the sum of the required and optional dwell time positions define, in effect, the limits of a time interval during which a given target pattern can be said to match an incoming sequence of frame patterns. The incoming audio spectra are processed to enhance the separation between the spectral pattern classes during later analysis. The processed audio spectra are grouped into multi-frame spectral patterns and are compared, using likelihood statistics, with the target patterns of the element templates. Each multi-frame pattern input, which inputs occur at a frame rate which requires each keyword target pattern to correspond to at least two of the multi-frame patterns, is forced to contribute to each of a plurality of pattern scores as represented by the element templates. The contributions of said multi-frame pattern inputs to said pattern scores is controlled, in part, by said required and optional dwell time constraints. A concatenation technique is employed, using dynamic programming techniques, to determine the correct identity of the word string.

F0 rule for discourse

Abstract: Rules for the fundamental frequency (F0) contour for discourse have been formulated. The rules are based on F0 data that consider boundaries and segmental factors in a number of natural readings. The rules give F0 within a word according to stress and boundary values, and a concatenation rule is applied to obtain the continuous F0 across two adjacent words. The rules have been tested on a naturally read story using an LPC vocoder synthesis. A demonstration tape will be played.

Continuous word recognition apparatus

Abstract: A system for recognizing a continuously spoken word sequence with reference to preselected reference words with the problem of coarticulation removed, comprises a pattern memory for memorizing demi-word pair reference patterns consisting of a former and a latter reference pattern segment for each reference word and a word pair reference pattern segment for each permutation with repetition of two words selected from the preselected reference words. A recognition unit is operable as a finite-state automaton on concatenating the demi-word pair reference patterns so that no contradiction occurs at each interface of the reference patterns in every concatenation. It is possible to use the automaton in restricting the number of reference patterns in each concatenation either to an odd or an even positive integer.