Microphone calibration
First Claim
1. An apparatus comprising:
- an interface configured to receive a first digitized signal stream and a second digitized signal stream, wherein the first digitized signal stream and the second digitized signal stream correspond to an acoustic signal captured by a first microphone and a second microphone, respectively;
a processor, in communication with the interface, configured to run a module stored in memory, wherein the module is configured to;
determine a first time-frequency representation of the first digitized signal stream and a second time-frequency representation of the second digitized signal stream, wherein the first time-frequency representation indicates a magnitude of the first digitized signal stream for a plurality of frequencies at a plurality of time frames, and wherein the second time-frequency representation indicates a magnitude of the second digitized signal stream for the plurality of frequencies for the plurality of time frames;
determine a relationship between the first time-frequency representation and the second time-frequency representation at the plurality of time frames for a first of the plurality of frequencies; and
determine a magnitude calibration factor between the first microphone and the second microphone for the first of the plurality of frequencies based on the relationship between the first time-frequency representation and the second time-frequency representation.
1 Assignment
0 Petitions
Accused Products
Abstract
The disclosed apparatus, systems, and methods provide a calibration technique for calibrating a set of microphones. The disclosed calibration technique is configured to calibrate the microphones with respect to a reference microphone and can be used in actual operation rather than a testing environment. The disclosed calibration technique can estimate both the magnitude calibration factor for compensating magnitude sensitivity variations and the relative phase error for compensating phase delay variations. In addition, the disclosed calibration technique can be used even when multiple acoustic sources are present. The disclosed technique is particularly well suited to calibrating a set of microphones that are omnidirectional and sufficiently close to one another.
-
Citations
20 Claims
-
1. An apparatus comprising:
-
an interface configured to receive a first digitized signal stream and a second digitized signal stream, wherein the first digitized signal stream and the second digitized signal stream correspond to an acoustic signal captured by a first microphone and a second microphone, respectively; a processor, in communication with the interface, configured to run a module stored in memory, wherein the module is configured to; determine a first time-frequency representation of the first digitized signal stream and a second time-frequency representation of the second digitized signal stream, wherein the first time-frequency representation indicates a magnitude of the first digitized signal stream for a plurality of frequencies at a plurality of time frames, and wherein the second time-frequency representation indicates a magnitude of the second digitized signal stream for the plurality of frequencies for the plurality of time frames; determine a relationship between the first time-frequency representation and the second time-frequency representation at the plurality of time frames for a first of the plurality of frequencies; and determine a magnitude calibration factor between the first microphone and the second microphone for the first of the plurality of frequencies based on the relationship between the first time-frequency representation and the second time-frequency representation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
-
-
13. A method comprising:
-
receiving, by a data processing module coupled to a first microphone and a second microphone, a first digitized signal stream and a second digitized signal stream, wherein the first digitized signal stream and the second digitized signal stream correspond to an acoustic signal captured by the first microphone and the second microphone, respectively; determining, by the data processing module, a first time-frequency representation of the first digitized signal stream and a second time-frequency representation of the second digitized signal stream, wherein the first time-frequency representation indicates a magnitude of the first digitized signal stream for a plurality of frequencies at a plurality of time frames, and wherein the second time-frequency representation indicates a magnitude of the second digitized signal stream for the plurality of frequencies for the plurality of time frames; determining, by a calibration module in communication with the data processing module, a relationship between the first time-frequency representation and the second time-frequency representation at the plurality of time frames for a first of the plurality of frequencies; and determining, by the calibration module, a magnitude calibration factor between the first microphone and the second microphone for the first of the plurality of frequencies based on the relationship between the first time-frequency representation and the second time-frequency representation. - View Dependent Claims (14, 15, 16, 17)
-
-
18. A non-transitory computer readable medium having executable instructions operable to cause a data processing apparatus to:
-
receive, over an interface coupled to a first microphone and a second microphone, a first digitized signal stream and a second digitized signal stream, wherein the first digitized signal stream and the second digitized signal stream correspond to an acoustic signal captured by the first microphone and the second microphone, respectively; determine a first time-frequency representation of the first digitized signal stream and a second time-frequency representation of the second digitized signal stream, wherein the first time-frequency representation indicates a magnitude of the first digitized signal stream for a plurality of frequencies at a plurality of time frames, and wherein the second time-frequency representation indicates a magnitude of the second digitized signal stream for the plurality of frequencies for the plurality of time frames; determine a relationship between the first time-frequency representation and the second time-frequency representation at the plurality of time frames for a first of the plurality of frequencies; and determine a magnitude calibration factor between the first microphone and the second microphone for the first of the plurality of frequencies based on the relationship between the first time-frequency representation and the second time-frequency representation. - View Dependent Claims (19, 20)
-
Specification