Speech Recognition Systems for Man Machine Interaction

The fundamental mode of communication among humans is speech and in the case of machine-human interface; verbal language has been believed as the natural method. When communication with machines is carried out, it is very difficult and slow-moving in magnitude when realized via keyboards, mouses and other devices. Thus, speech feed-in is an important constituent to making this communication easily accessible. Also, humans see speech as a great source of information. Therefore, persons who are not literate or have vague about computers can easily access computers by employing speech instructions. Even people with some physical disability who are not able to type or click with their hands can use their speech to operate the computer. Even people who are proficient in operating computers can speed up data entry, sending emails and other documents using the speech input methods. Furthermore, this mode of operation possesses many advantages. For example, while driving, the hands of the driver are busy steering the driving wheel and he cannot type on his mobile. In such a case speech is a good input option. GPS (Global Positioning System) is an example of a speech-based system being used. Another example is speech-enabled dialing, where the user can just ask the device to call a particular person, without dialing his number.The common and efficient means of communication among humans is through 'speech'. To process speech means to extract useful information from it, processing includes the implementation of electric signals on the acoustic pressure waves collected from human vocalization and applying mathematical analysis to it. The field of processing speech involves the natural operation of analysing speech, coding, augmentation, synthesis, and recognition. Analysis of speech is the study of its creation mechanism to make a mathematical model of physical phenomena. Speech coding aims to keep information about specific speech parameters for later retrieval. The method of refining precision and quality of speech which is noisy utilises various algorithms is recognized as speech enhancement [2]. Producing artificial human speech using coded information is known as the synthesis of speech. The method of inverse synthesis is the capability of a program or machine to classify the linguistic contents mixed up in the speech signal.