tailieunhanh - Digital Signal Processing Handbook P39

Conclusions References In this chapter we review properties of auditory perception that are relevant to the design of coders for acoustic signals. The chapter begins with a general definition of a | Jenkins W. K. Auditory Psychophysics for Coding Applications Digital Signal Processing Handbook Ed. Vijay K. Madisetti and Douglas B. Williams Boca Raton CRC Press LLC 1999 1999 by CRC Press LLC Hall . Auditory Psychophysics for Coding Applications Digital Signal Processing Handbook Ed. Vijay K. Madisetti and Douglas B. Williams Boca Raton CRC Press LLC 1999 1999 by CRC Press LLC 39 Auditory Psychophysics for Coding Applications Joseph L. Hall Bell Laboratories Lucent Technologies Introduction Definitions Loudness Pitch Threshold of Hearing Differential Threshold Masked Threshold Critical Bands and Peripheral Auditory Filters Summary of Relevant Psychophysical Data Loudness Differential Thresholds Masking Conclusions References In this chapter we review properties of auditory perception that are relevant to the design of coders for acoustic signals. The chapter begins with a general definition of a perceptual coder then considers what the ideal psychophysical model would consist of and what use a coder could be expected to make of this model. We then present some basic definitions and concepts. The chapter continues with a review of relevant psychophysical data including results on threshold just-noticeable differences masking and loudness. Finally we attempt to summarize the present state of the art the capabilities and limitations of present-day perceptual coders for audio and speech and what areas most need work. Introduction A coded signal differs in some respect from the original signal. One task in designing a coder is to minimize some measure of this difference under the constraints imposed by bit rate complexity or cost. What is the appropriate measure of difference The most straightforward approach is to minimize some physical measure of the difference between original and coded signal. The designer might attempt to minimize RMS difference between the original and coded waveform or perhaps the difference between original and .