Patent ID: 8767971

Claim:
A sound pickup apparatus comprising: a microphone including 4 sound pickup units placed so as to have main axis directions of directivity separated by 90 degrees, the microphone being installed in a position where sound outputted from a loudspeaker, which reproduces a voice signal received from a communication partner site, can be picked up; a level calculating unit configured to calculate a signal level of sound outputted from the loudspeaker for each output signal of the 4 sound pickup units; a mixing coefficient calculating unit configured to calculate a mixing coefficient adjusted to main axis directions of directivity of the 4 sound pickup units by using the signal level calculated by said level calculating unit, the mixing coefficient being for generating a stereo signal including a R channel signal whose main axis of directivity is inclined to the left with respect to a direction from the microphone to the loudspeaker, and a L channel signal whose main axis of directivity is inclined to the right with respect to the direction from the microphone to the loudspeaker; and a signal mixing unit configured to generate a stereo signal by mixing output signals of the 4 sound pickup units by using a mixing coefficient calculated by said mixing coefficient calculating unit, wherein the mixing coefficient includes a first mixing coefficient for generating the R channel signal, and a second mixing coefficient for generating the L channel signal, wherein for each one of the 4 sound pickup units, said mixing coefficient calculation unit is configured to calculate the first mixing coefficient by using a signal level of another sound pickup unit located to the left of the sound pickup unit, and calculate the second mixing coefficient by using a signal level of another sound pickup unit located to the right of the sound pickup unit, and wherein said signal mixing unit is configured to generate the R channel signal by multiplying output signals of the 4 sound pickup units by the respective first mixing coefficients and adding the multiplied output signals together, and generate the L channel signal by multiplying output signals of the 4 sound pickup units by the respective second mixing coefficients and adding the multiplied output signals together.