Mitsubishi Denki Kabushiki Kaisha

Mitsubishi Electric Corporation

Tomoko Ishii

Shigeaki Suzuki

Masaru Kimura

Nobuyoshi Horie

With stereophonic sound images of multi-channel audio signals well maintained, 2-channel system audio signals are created. An acoustic image creation system includes: a left-rear localization processing meansfor outputting a left-rear localization signal by summing together a left signaland a left-rear signal, among audio input signals including the left signal, a right signal, the left-rear signal, and a right-rear signal, and processing the summation result with a rear localization processing filter; a right-rear localization processing meansfor outputting a right-rear localization signal by summing together the right signaland the right-rear signal, and processing the summation result with a rear localization processing filter; and an acoustic image creation meansfor creating the surround sound image signals from the left signal, the right signal, the left-rear localization signal, and the right-rear localization signal

Acoustic image creation system and program therefor

A counter increments a count value every given time period. An adaptive operation control unit selects channels in which adaptive operations are done from all the channels in obedience to the count value to output produced selection signals to AND circuits. Double-talk detection circuits judge the presence/absence of a double-talk state and output detection signals to the AND circuits. The AND circuits operate logical AND of the selection signals and the detection signals and output the logical AND results as control signals to filter coefficient updating circuits. The filter coefficient updating circuits update or do not update filter coefficients stored in FIR filter units according to the control signals. The FIR filter units produce echo replicas by calculating convolutions of the filter coefficients and the receive signals. Subtractors subtract the echo replicas from transmission signals to output residual signals.

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Tokyo, Japan

Tomoko Ishii