Signal processing methods and systems for rendering audio on virtual loudspeaker arrays
First Claim
1. A method of rendering sound fields in a left ear and a right ear of a human listener, the sound fields being produced by a plurality of virtual loudspeakers, the method comprising:
- obtaining, by processing circuitry of a sound rendering computer configured to render the sound fields in the left ear and the right ear of the head of the human listener, a plurality of head-related impulse responses (HRIRs), each of the plurality of HRIRs being associated with a virtual loudspeaker of the plurality of virtual loudspeakers and the left or right ear of the human listener, each of the plurality of HRIRs including samples of a sound field produced at a specified sampling rate in the left or right ear produced in response to an audio impulse produced by that virtual loudspeaker;
generating a first state space representation of each of the plurality of HRIRs, the first state space representation including a matrix, a column vector, and a row vector, each of the matrix, the column vector, and the row vector of the first state space representation having a first size;
performing a state space reduction operation to produce a second state space representation of each of the plurality of HRIRs, the second state space representation including a matrix, a column vector, and a row vector, each of the matrix, the column vector, and the row vector of the second state space representation having a second size that is less than the first size; and
producing a plurality of head-related transfer functions (HRTFs) based on the second state space representation, each of the plurality of HRTFs corresponding to a respective HRIR of the plurality of HRIRs, an HRTF corresponding to the respective HRIR producing, upon multiplication by a frequency-domain sound field produced by the virtual loudspeaker with which the respective HRIR is associated, a component of the sound field rendered in the left or right ear of the human listener.
2 Assignments
0 Petitions
Accused Products
Abstract
Techniques of rendering audio involve applying a balanced-realization state space model to each head-related transfer function (HRTF) to reduce the order of an effective FIR or even an infinite impulse response (IIR) filter. Along these lines, each HRTF G(z) is derived from a head-related impulse response filter (HRIR) via, e.g., a z-transform. The data of the HRIR may be used to construct a first state space representation [A, B, C, D] of the HRTF via the relation G(z)=C(zI−A)−1B+D This first state space representation is not unique and so for an FIR filter, A and B may be set to simple, binary-valued arrays, while C and D contain the HRIR data. This representation leads to a simple form of a Gramian Q whose eigenvectors provide system states that maximize the system gain as measured by a Hankel norm.
63 Citations
20 Claims
-
1. A method of rendering sound fields in a left ear and a right ear of a human listener, the sound fields being produced by a plurality of virtual loudspeakers, the method comprising:
-
obtaining, by processing circuitry of a sound rendering computer configured to render the sound fields in the left ear and the right ear of the head of the human listener, a plurality of head-related impulse responses (HRIRs), each of the plurality of HRIRs being associated with a virtual loudspeaker of the plurality of virtual loudspeakers and the left or right ear of the human listener, each of the plurality of HRIRs including samples of a sound field produced at a specified sampling rate in the left or right ear produced in response to an audio impulse produced by that virtual loudspeaker; generating a first state space representation of each of the plurality of HRIRs, the first state space representation including a matrix, a column vector, and a row vector, each of the matrix, the column vector, and the row vector of the first state space representation having a first size; performing a state space reduction operation to produce a second state space representation of each of the plurality of HRIRs, the second state space representation including a matrix, a column vector, and a row vector, each of the matrix, the column vector, and the row vector of the second state space representation having a second size that is less than the first size; and producing a plurality of head-related transfer functions (HRTFs) based on the second state space representation, each of the plurality of HRTFs corresponding to a respective HRIR of the plurality of HRIRs, an HRTF corresponding to the respective HRIR producing, upon multiplication by a frequency-domain sound field produced by the virtual loudspeaker with which the respective HRIR is associated, a component of the sound field rendered in the left or right ear of the human listener. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
-
-
11. A computer program product comprising a nontransitive storage medium, the computer program product including code that, when executed by processing circuitry of a sound rendering computer configured to render sound fields in a left ear and a right ear of a human listener, causes the processing circuitry to perform a method, the method comprising:
-
obtaining a plurality of head-related impulse responses (HRIRs), each of the plurality of HRIRs being associated with a virtual loudspeaker of a plurality of virtual loudspeakers and the left or right ear of the human listener, each of the plurality of HRIRs including samples of a sound field produced at a specified sampling rate in the left or right ear produced in response to an audio impulse produced by that virtual loudspeaker; generating a first state space representation of each of the plurality of HRIRs, the first state space representation including a matrix, a column vector, and a row vector, each of the matrix, the column vector, and the row vector of the first state space representation having a first size; performing a state space reduction operation to produce a second state space representation of each of the plurality of HRIRs, the second state space representation including a matrix, a column vector, and a row vector, each of the matrix, the column vector, and the row vector of the second state space representation having a second size that is less than the first size; and producing a plurality of head-related transfer functions (HRTFs) based on the second state space representation, each of the plurality of HRTFs corresponding to a respective HRIR of the plurality of HRIRs, an HRTF corresponding to a respective HRIR producing, upon multiplication by a frequency-domain sound field produced by the virtual loudspeaker with which the respective HRIR is associated, a component of a sound field rendered in the left or right ear of the human listener. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19)
-
-
20. An electronic apparatus configured to render sound fields in a left ear and a right ear of a human listener, the electronic apparatus comprising:
-
memory; and controlling circuitry coupled to the memory, the controlling circuitry being configured to; obtain a plurality of head-related impulse responses (HRIRs), each of the plurality of HRIRs being associated with a virtual loudspeaker of a plurality of virtual loudspeakers and the left or right ear of the human listener, each of the plurality of HRIRs including samples of a sound field produced at a specified sampling rate in the left or right ear produced in response to an audio impulse produced by that virtual loudspeaker; generate a first state space representation of each of the plurality of HRIRs, the first state space representation including a matrix, a column vector, and a row vector, each of the matrix, the column vector, and the row vector of the first state space representation having a first size; perform a state space reduction operation to produce a second state space representation of each of the plurality of HRIRs, the second state space representation including a matrix, a column vector, and a row vector, each of the matrix, the column vector, and the row vector of the second state space representation having a second size that is less than the first size; and produce a plurality of head-related transfer functions (HRTFs) based on the second state space representation, each of the plurality of HRTFs corresponding to a respective HRIR of the plurality of HRIRs, an HRTF corresponding to a respective HRIR producing, upon multiplication by a frequency-domain sound field produced by the virtual loudspeaker with which the respective HRIR is associated, a component of a sound field rendered in the left or right ear of the human listener.
-
Specification