Data processing: speech signal processing – linguistics – language – Speech signal processing – For storage or transmission
Patent
1995-02-21
1998-04-07
MacDonald, Allen R.
Data processing: speech signal processing, linguistics, language
Speech signal processing
For storage or transmission
704204, 704226, 704227, G10L 302
Patent
active
057377170
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to a signal transforming method and a signal transforming apparatus applied to, e.g., digital audio equipments and adapted for altering (changing) sound quality (i.e., transforming the characteristic of time signal information) by using particularly the property of the hearing sense with respect to an input audio signal which is a time signal, and a recording medium adapted so that information in which characteristic of time signal information is transformed by such method or apparatus is recorded thereonto or thereinto.
BACKGROUND ART
Hitherto, as a technique for altering (changing) sound quality of acoustic (audible) signal information, there are used, e.g., a system of altering the frequency characteristic by filtering processing, a system for producing higher harmonic (wave), a system of altering (changing) dynamic range by so called compressor, and the like.
However, in the case of the system using filter, how to use filter is changed e.g., a medium frequency band is enhanced to improve presence, etc., thus to change sound quality. In the system of producing higher harmonic (wave), use in a manner of sound effect is applied rather than sound easy to be heard is obtained. In addition, the system of changing (altering) dynamic range by compressor is a system such that big sound is not caused to be disagreeable to the ear, or soft sound is not caused to be masked by the ambient noise. With these systems, it is difficult to carry out optimum control such that sound agreeable to the ear is provided from a viewpoint of the hearing sense in a manner to cope with changes of acoustic signal information varying moment by moment.
In view of actual circumstances as described above, this invention has been proposed, and its object is to provide a signal transforming method and a signal transforming apparatus capable of transforming speech and acoustic signals significant with respect to sound quality from a viewpoint of the hearing sense of the human being, and a recording medium adapted so that speech or acoustic signal information of which characteristic is transformed by the above-mentioned method or apparatus is recorded thereonto or thereinto.
Namely, the task that this invention contemplates solving is to provide an technique for implementing a predetermined transform processing to acoustic signal information to create sound which can be heard agreeably with high quality from a viewpoint of sound quality for the human being moment by moment by using the auditive (auditory) principle (principle from a viewpoint of the hearing sense). Moreover, another task of this invention is to lessen, from acoustic signal information which has been already digitized so that quantizing (quantization) noises are added thereto, auditive influence of such quantizing noises to thereby improve quality. A further task of this invention is to lessen, from audio signal information which has been already digitized so that quantizing noise are added thereto, auditive influence of quantizing noises thereafter to create (prepare) data of which sound quality is improved by auditive processing when recorded on compact disc having word length of 16 bits by the technology for reducing noise level from a viewpoint of the hearing sense by altering (changing) spectrum of quantizing noise so as to become in conformity with so called equi-loudness characteristic or masking characteristic which has been already proposed as the technology for improving sound quality of audio equipment such as so called compact disc by the applicant of this invention (this technology will be referred to as, e.g., Super Bit Mapping technology hereinafter), i.e., the technologies disclosed in, e.g., Tokkaihei No. 2-20812 (Japanese Patent Application Laid Open No. 20812/1990), Tokkaihei No. 2-185552 (Japanese Patent Application Laid Open No. 185552/1990), and Tokkaihei No. 2-185556 (Japanese Patent Application Laid Open NO. 185556/1990). In accordance with the Super Bit Mapping technology, in the case of re-quantizing digita
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Akagiri Kenzo
Akune Makoto
Collins Alphonso A.
MacDonald Allen R.
Sony Corporation
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