Patents by Inventor Koji Niimi

Koji Niimi has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 7925008
    Abstract: Stereo sound signals are reproduced directly from loudspeakers (SP(L), SP(R)). By using a sum signal and a difference signal of the stereo sound signals as a reference signal, and according to a cross spectrum calculation of the reference signal with a microphone-collected sound signal, calculation is performed to obtain transfer functions of four sound transfer systems between the loudspeakers (SP(L), SP(R)) and microphones (MC(L), MC(R)). The transfer functions obtained are subjected to inverse Fourier transform to obtain impulse responses, which are set in filter means (40-1 to 40-4) to create echo cancel signals and perform echo canceling. This solves the problem of an indefinite coefficient in the echo cancel technique of a multi-channel sound signal.
    Type: Grant
    Filed: July 5, 2007
    Date of Patent: April 12, 2011
    Assignee: Yamaha Corporation
    Inventors: Toru Hirai, Mikio Tohyama, Hiraku Okumura, Yoshikazu Honji, Hiroshi Iriyama, Koji Niimi
  • Patent number: 7925006
    Abstract: Stereo sound signals are reproduced directly from loudspeakers (SP(L), SP(R)). By using a sum signal and a difference signal of the stereo sound signals as a reference signal, and according to a cross spectrum calculation of the reference signal with a microphone-collected sound signal, calculation is performed to obtain transfer functions of four sound transfer systems between the loudspeakers (SP(L), SP(R)) and microphones (MC(L), MC(R)). The transfer functions obtained are subjected to inverse Fourier transform to obtain impulse responses, which are set in filter means (40-1 to 40-4) to create echo cancel signals and perform echo canceling. This solves the problem of an indefinite coefficient in the echo cancel technique of a multi-channel sound signal.
    Type: Grant
    Filed: July 5, 2007
    Date of Patent: April 12, 2011
    Assignee: Yamaha Corporation
    Inventors: Toru Hirai, Mikio Tohyama, Hiraku Okumura, Yoshikazu Honji, Hiroshi Iriyama, Koji Niimi
  • Patent number: 7403609
    Abstract: Stereo sound signals are reproduced directly from loudspeakers (SP(L), SP(R)). By using a sum signal and a difference signal of the stereo sound signals as a reference signal, and according to a cross spectrum calculation of the reference signal with a microphone-collected sound signal, calculation is performed to obtain transfer functions of four sound transfer systems between the loudspeakers (SP(L), SP(R)) and microphones (MC(L), MC(R)). The transfer functions obtained are subjected to inverse Fourier transform to obtain impulse responses, which are set in filter means (40-1 to 40-4) to create echo cancel signals and perform echo canceling. This solves the problem of an indefinite coefficient in the echo cancel technique of a multi-channel sound signal.
    Type: Grant
    Filed: November 7, 2003
    Date of Patent: July 22, 2008
    Assignee: Yamaha Corporation
    Inventors: Toru Hirai, Mikio Tohyama, Hiraku Okumura, Yoshikazu Honji, Hiroshi Iriyama, Koji Niimi
  • Publication number: 20070258579
    Abstract: Stereo sound signals are reproduced directly from loudspeakers (SP(L), SP(R)). By using a sum signal and a difference signal of the stereo sound signals as a reference signal, and according to a cross spectrum calculation of the reference signal with a microphone-collected sound signal, calculation is performed to obtain transfer functions of four sound transfer systems between the loudspeakers (SP(L), SP(R)) and microphones (MC(L), MC(R)). The transfer functions obtained are subjected to inverse Fourier transform to obtain impulse responses, which are set in filter means (40-1 to 40-4) to create echo cancel signals and perform echo canceling. This solves the problem of an indefinite coefficient in the echo cancel technique of a multi-channel sound signal.
    Type: Application
    Filed: July 5, 2007
    Publication date: November 8, 2007
    Inventors: Toru Hirai, Mikio Tohyama, Hiraku Okumura, Yoshikazu Honji, Hiroshi Iriyama, Koji Niimi
  • Publication number: 20070258578
    Abstract: Stereo sound signals are reproduced directly from loudspeakers (SP(L), SP(R)). By using a sum signal and a difference signal of the stereo sound signals as a reference signal, and according to a cross spectrum calculation of the reference signal with a microphone-collected sound signal, calculation is performed to obtain transfer functions of four sound transfer systems between the loudspeakers (SP(L), SP(R)) and microphones (MC(L), MC(R)). The transfer functions obtained are subjected to inverse Fourier transform to obtain impulse responses, which are set in filter means (40-1 to 40-4) to create echo cancel signals and perform echo canceling. This solves the problem of an indefinite coefficient in the echo cancel technique of a multi-channel sound signal.
    Type: Application
    Filed: July 5, 2007
    Publication date: November 8, 2007
    Inventors: Toru Hirai, Mikio Tohyama, Hiraku Okumura, Yoshikazu Honji, Hiroshi Iriyama, Koji Niimi
  • Patent number: 6835885
    Abstract: A time-axis compression/expansion method and apparatus for multitrack signals is provided, which is capable of performing time-axis compression/expansion on a multitrack signal in such an appropriate manner as to prevent a degradation in the sound quality of a sound generated through a multichannel reproduction or a sound generated through reproduction of a musical tone signal obtained by mix-down. Positions of attacks of the rhythm track sound source signal of a plurality of track sound source signals are detected. Portions of the rhythm track sound source signal between the detected positions of attacks are subjected to a first time-axis compression/expansion process, and the other track sound source signals are subjected to a second time-axis compression/expansion process, based on the detected positions of attacks.
    Type: Grant
    Filed: August 9, 2000
    Date of Patent: December 28, 2004
    Assignee: Yamaha Corporation
    Inventors: Kazunobu Kondo, Koji Niimi
  • Publication number: 20040174991
    Abstract: Stereo sound signals are reproduced directly from loudspeakers (SP(L), SP(R)). By using a sum signal and a difference signal of the stereo sound signals as a reference signal, and according to a cross spectrum calculation of the reference signal with a microphone-collected sound signal, calculation is performed to obtain transfer functions of four sound transfer systems between the loudspeakers (SP(L), SP(R)) and microphones (MC(L), MC(R)). The transfer functions obtained are subjected to inverse Fourier transform to obtain impulse responses, which are set in filter means (40-1 to 40-4) to create echo cancel signals and perform echo canceling. This solves the problem of an indefinite coefficient in the echo cancel technique of a multi-channel sound signal.
    Type: Application
    Filed: November 7, 2003
    Publication date: September 9, 2004
    Applicant: YAMAHA CORPORATION
    Inventors: Toru Hirai, Mikio Tohyama, Hiraku Okumura, Yoshikazu Honji, Hiroshi Iriyama, Koji Niimi
  • Patent number: 6362764
    Abstract: Most appropriate data of a plurality of level-converted digital data obtained by level conversion of the same input digital data by different conversion factors is selected based on a signal quality of each level-converted digital data. The other level-converted digital data is attenuated to or below a predetermined noise level. Switching between previously selected data and newly selected data is effected by cross-fading. The level-converted digital data are D/A converted to respective analog signals. Level conversion of the analog signals are carried out again based on respective corresponding ones of the conversion factors to restore a level of the input digital data, and all the level-converted analog signals are then added together.
    Type: Grant
    Filed: July 20, 2000
    Date of Patent: March 26, 2002
    Assignee: Yamaha Corporation
    Inventors: Koji Niimi, Ryuuji Wakatsuki, Kiyoto Kuroiwa
  • Patent number: 6084974
    Abstract: A digital signal processing device includes a rectifier circuit, logarithm conversion circuit, peak-hold/timewise attenuation circuit, gain table, multiplier and timing generation circuit. The rectifier circuit obtains the absolute value of input data. The logarithm conversion circuit converts the linear input data into logarithmic data. The peak-hold/timewise attenuation circuit performs peak-hold and timewise attenuation processes on the instantaneous logarithmic data, to obtain an approximate logarithmic envelope. The gain table which has nonlinear gain characteristic receives the logarithmic data as a readout address, to thereby output a gain value corresponding to the input level. The multiplier multiplies the input data by the gain value so as to provide output data that have been processed in accordance with the nonlinear characteristic.
    Type: Grant
    Filed: May 17, 1994
    Date of Patent: July 4, 2000
    Assignee: Yamaha Corporation
    Inventor: Koji Niimi
  • Patent number: 6073746
    Abstract: An assembled part for being placed on a conveyor frame having a pair of guides along a direction of conveyance, being located between an upstream delivery member and a downstream positioning member and being conveyed and guided through the movement of them as one body, which includes a main body, a pair of guided portions facing the guides, a delivered portion facing the delivery member, a positioned portion facing the positioning member.
    Type: Grant
    Filed: June 20, 1996
    Date of Patent: June 13, 2000
    Assignee: Asmo Co., Ltd.
    Inventors: Akio Oshiro, Koji Niimi, Tomomi Nakamura, Ryousuke Sakamaki, Masanori Oishi
  • Patent number: 5365468
    Abstract: A sampling frequency converter includes an oversampling circuit for oversampling an input sample train, a Random Access Memory (RAM), a write control circuit for writing oversampled data in the RAM with a clock synchronized with the oversampled data, a sampling frequency ratio measuring circuit for measuring a frequency ratio of a sampling frequency of the input sample train and a sampling frequency of an output sample train, a read control circuit for reading from the RAM the oversampled data used for obtaining interpolation data at two points before and after an output sample value which realizes the measured sampling frequency ratio by a polynomial interpolation, a polynomial interpolation circuit for obtaining the interpolation data at the two points by the polynomial interpolation on the basis of the oversampled data read from the RAM by the read control circuit, and a linear interpolation circuit for linear-interpolating between the polynomial interpolation data at the two points and thereby obtaining t
    Type: Grant
    Filed: September 14, 1993
    Date of Patent: November 15, 1994
    Assignee: Yamaha Corporation
    Inventors: Yuji Kakubo, Shigeki Kimura, Hiromi Sotome, Koji Niimi
  • Patent number: 4803731
    Abstract: A reverberation imparting device comprises a delay memory storing input signal data at a predetermined sampling period and producing a delay signal corresponding to time interval between writing of the input signal data and reading thereof, a plurality of address each adding delay signals read out from the delay memory, and an output section for delivering out an output of each of the adders as a reverberation signal. The delay signals are divided into groups and processed on the group basis. This simplifies the construction of the device and facilitates setting and changing of the reverberation characteristics.
    Type: Grant
    Filed: August 24, 1987
    Date of Patent: February 7, 1989
    Assignee: Yamaha Corporation
    Inventors: Koji Niimi, Yuji Kakubo, Yuji Ikegaya
  • Patent number: 4706291
    Abstract: A reverberation imparting device comprises a prememory storing an input signal, a level detection circuit responsive to data stored in the prememory for detecting presence or absence of the input signal, a data memory storing a delayed input signal delivered out of the prememory, a fixed type convolution operation circuit for producing a reverberation signal with respect to the data stored in the prememory by using an initial portion of parameters of a reflected sound, an adaptive type convolution operation circuit for producing a reverberation signal with respect to data stored in the data memory by using a plurality of parameters of more significant bits among the remaining portion of the parameters of the reflected sound, and an adder for adding outputs of the fixed type and adaptive type convolution circuits and delivering out the result of addition as a reverberation signal.
    Type: Grant
    Filed: June 23, 1986
    Date of Patent: November 10, 1987
    Assignee: Nippon Gakki Seizo Kabushiki Kaisha
    Inventors: Yuji Kakubo, Koji Niimi, Yuji Ikegaya
  • Patent number: 4587620
    Abstract: A noise elimination device employs a concept of the linear prediction method. According to the invention, a linear prediction coefficient of a digitized, continuous input signal (an original signal) is calculated, a linear predicted value is computed from this linear prediction coefficient, difference (a prediction error) between the linear predicted value and the input signal is computed whereas a threshold value is set in accordance with the momentarily changing input signal, the judgement that a noise has occurred is made when the predicted value has exceeded the threshold value and thereupon a substitution signal is produced on the basis of an input signal existing in the vicinity of the time point at which the noise has occurred, and the section in which the noise has occurred is substituted by this substitution signal thereby to eliminate the noise.
    Type: Grant
    Filed: April 30, 1982
    Date of Patent: May 6, 1986
    Assignee: Nippon Gakki Seizo Kabushiki Kaisha
    Inventors: Koji Niimi, Takayasu Kondo
  • Patent number: 4389892
    Abstract: A device for measuring reverberation characteristics in a reverberation room by a digital squaring and integrating computation process. According to the invention, only a part of digital data of a large word length obtained by squaring and integrating a reverberation signal is selected out for computing the reverberation characteristics in accordance with a measuring environment such as integration time and duration of a test pulse. By this arrangement, circuitry for computing the reverberation characteristics can be made compact and time required for computing can be shortened without sacrificing the accuracy of measurement. Further, according to the invention, the level of an input signal can be computed and displayed by computing intermediate squared and integrated data at a certain time interval and adding this data with compensation data corresponding to a frequency band width of the input signal.
    Type: Grant
    Filed: April 20, 1981
    Date of Patent: June 28, 1983
    Assignee: Nippon Gakki Seizo Kabushiki Kaisha
    Inventors: Koji Niimi, Fukushi Kawakami
  • Patent number: 4258602
    Abstract: In an electronic keyboard musical instrument, the operation of a key causes a corresponding frequency information signal to be read out of a frequency information memory. The frequency information signal represents a counting number and is repeatedly accumulated in an accumulator at a first clock rate. The accumulator generates carry signals at a frequency defining a tone frequency. A wave shape memory stores sample values of a wave shape, and a counter addresses this memory to read out the wave shape. The counter is driven at a second clock rate to successively address the sample values one after another, but is reset by the carry signals to restore it to its initial state. Thus the memory generates only those sample values of the wave shape which fall within the carry signal period from the beginning. The tone colors will vary from one tone frequency to another.
    Type: Grant
    Filed: July 7, 1978
    Date of Patent: March 31, 1981
    Assignee: Nippon Gakki Seizo Kabushiki Kaisha
    Inventors: Koji Niimi, Mitsumi Kotah
  • Patent number: 4246823
    Abstract: In a wave shape generator of the memory reading type, a waveshape memory stores sample values of a wave each value being represented by an integral address. A coefficient memory stores coefficients for nth order interpolation. Unknown intermediate sample values not stored in the wave shape memory represented by non-integral addresses and are approximated by multiplication of stored sample values of the waveshape and corresponding coefficient values on the basis of nth order interpolation. Use of the interpolation method assures smoothness of the wave shape with respect to time and thereby minimizes quantization noise while permitting use of relatively small memories.
    Type: Grant
    Filed: October 30, 1978
    Date of Patent: January 27, 1981
    Assignee: Nippon Gakki Seizo Kabushiki Kaisha
    Inventors: Masatada Wachi, Mitsumi Katoh, Koji Niimi
  • Patent number: 4244257
    Abstract: A wave-shape generator advantageously used for generation of various wave-shape signals on electronic musical instruments comprises, as a substitute for multiple wave-shape memories needed in the conventional wave-shape generators, a combination of a single wave-shape memory with a weighting parameter signal generator. Modulation of the wave-shape signals via multiplication by corresponding weighting parameter signals enables formation of a wide variety of different wave-shape signals without enlargement in construction, the wave-shape signals being changeable even in a time-functional fashion too.
    Type: Grant
    Filed: March 26, 1979
    Date of Patent: January 13, 1981
    Assignee: Nippon Gakki Seizo Kabushiki Kaisha
    Inventors: Koji Niimi, Takayasu Kondo, Shigeo Ando
  • Patent number: RE30834
    Abstract: The musical instrument is of a waveform memory device read out type and comprises a frequency information generator for generating a plurality of sets of frequency informations each set consisting of a subplurality of frequency informations and corresponding to each of the tone pitches of the depressed keys in a keyboard, a selector for selecting one, at a time and one after another, of the subplurality of frequency informations generated by the frequency information generator for each one key depressed, an accumulator for repeatedly accumulating the frequency information selected by the selector to produce an increasing accumulated value, a waveform memory device for storing the amplitude values at successive sampling points in one period of a sine wave utilized to form a desired musical waveform, a comparator for comparing the accumulated value with a preset value and controlling the selecting operation of the selector during the operation of the accumulator.
    Type: Grant
    Filed: May 30, 1980
    Date of Patent: December 29, 1981
    Assignee: Nippon Gakki Seizo Kabushiki Kaisha
    Inventors: Koji Niimi, Mitsumi Kato
  • Patent number: RE31004
    Abstract: A CPU of a computer, or preferably a so-called microprocessor controls the tone waveshape generation. A tone generator unit, an instrument keyboard unit, a tone quality control unit are connected to a common data bus to which the CPU and the associated memories are also connected. Thus, the tone generator unit may be considered as a terminal unit of a computer system. Hence, the freedom in selecting the algorithm for generating a waveshape and the freedom in selecting and changing the parameters related to the waveshape generation are substantially increased. And therefore a gradually changing waveshape is very easily generated in one embodiment of this invention.
    Type: Grant
    Filed: January 30, 1981
    Date of Patent: August 3, 1982
    Assignee: Nippon Gakki Seizo Kabushiki Kaisha
    Inventor: Koji Niimi