# US 8,788,265 B2 · System and method for babble noise detection > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,788,265 B2 - Document ID: US8788265B2 - Status: Granted - Kind: B2 - Application number: 10/853,819 - Filed: 2004-05-25 - Published: 2005-12-01 - Granted: 2014-07-22 - Earliest claimed: 2004-05-25 - Assignees: Nokia Solutions and Networks Oy - Applicants: Laura Laaksonen; Päivi Valve - Inventors: Laura Laaksonen; Päivi Valve - Web page: https://patentgrep.com/patent/US8788265B2 ## CPC - G10L 25/78: Detection of presence or absence of voice signals (switching of direction of transmission by voice frequency in two-way loud-speaking telephone systems H04M9/10) - G10L: SPEECH ANALYSIS TECHNIQUES OR SPEECH SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING TECHNIQUES; SPEECH OR AUDIO CODING OR DECODING ## Abstract A method, device, system, and computer program product calculate a gradient index as a sum of magnitudes of gradients of speech signals from a received frame at each change of direction; and provide an indication that the frame contains babble noise if the gradient index, energy information, and background noise level exceed pre-determined thresholds or a voice activity detector algorithm and sound level indicate babble noise. ## Claims ### Claim 1 A method, comprising: receiving an input signal including a speech signal; calculating a gradient index as a sum of magnitudes of gradients of speech signals from the received input signal at each change of direction; providing an indication that the input signal contains babble noise when the gradient index, energy information, and background noise level exceed pre-determined thresholds; and forcing an update of a long-term speech level estimate as a result of determining that the babble noise has been falsely indicated when a short-term speech level estimate does not reach the long-term speech level estimate for a given number of samples. ### Claim 2 (depends on 1) The method claim 1, further comprising performing a voice activity detector algorithm to determine whether the input signal contains babble noise. ### Claim 3 (depends on 2) The method of claim 2, wherein providing an indication that the input signal contains babble noise further comprises determining whether the input signal contains babble noise based on the gradient index, energy information, and background noise level exceeding pre-determined thresholds and/or a sound level of the input signal and the voice activity detector algorithm. ### Claim 4 (depends on 1) The method of claim 1, further comprising filtering the energy information and the gradient index. ### Claim 5 (depends on 4) The method of claim 4, wherein filtering the energy information and the gradient index is of the form H ⁡ ( z ) = 1 - a 1 - az - 1 , where a is an attack or release constant depending on the direction of change of the energy information. ### Claim 6 (depends on 4) The method of claim 4, wherein energy information and the gradient index are filtered using an IIR filter. ### Claim 7 A method, comprising: receiving an input signal including a speech signal; calculating a gradient index as a sum of magnitudes of gradients of speech signals from the received input signal at each change of direction; monitoring the input signal level using a voice activity detector algorithm; providing an indication that the input signal contains babble noise when the input signal level falls below a predetermined threshold level or when the gradient index, energy information, and background noise level exceed predetermined thresholds; and forcing an update of a long-term speech level estimate as a result of determining that the babble noise has been falsely indicated when a short-term speech level estimate does not reach the long-term speech level estimate for a given number of samples. ### Claim 8 A device, comprising: an interface configured to communicate with a wireless network; programmed instructions stored in a memory and configured to detect babble noise based on a spectral distribution of noise in accordance with gradient index, energy information and background noise level associated with a speech signal and configured to force an update a long-term speech level estimate as a result of determining that the babble noise has been falsely indicated when a short-term speech level estimate does not reach the long-term speech level estimate for a given number of samples. ### Claim 9 (depends on 8) The device of claim 8, wherein the spectral distribution of noise comprises checking whether a gradient index, energy information, and background noise level exceed predetermined thresholds. ### Claim 10 (depends on 8) The device of claim 8, further comprising programmed instructions to detect babble noise based on a voice activity detector algorithm. ### Claim 11 (depends on 8) The device of claim 8, wherein the detection of babble noise requires only one frame of speech signal. ### Claim 12 (depends on 8) The device of claim 8, further comprising filtering the energy information and the gradient index. ### Claim 13 A system, comprising: means for receiving a communication signal including a speech signal; means for calculating a gradient index as a sum of magnitudes of gradients of speech signals from the received communication signal at each change of direction; means for providing an indication that the communication signal contains babble noise when the gradient index, energy information, and background noise level exceed pre-determined thresholds; and means for forcing an update of a long-term speech level estimate as a result of determining that the babble noise has been falsely indicated when a short-term speech level estimate does not reach the long-term speech level estimate for a given number of samples. ### Claim 14 (depends on 13) The system of claim 13, further comprising means for determining whether the communication signal contains babble noise based on the gradient index, energy information, and background noise level exceeding pre-determined thresholds and/or a sound level of the communication signal and a voice activity detector algorithm. ### Claim 15 (depends on 14) The system of claim 14, further comprising means for detecting babble noise when the voice activity detector algorithm or the gradient index, energy information, and background noise level exceeds pre-determined thresholds is a false positive result. ### Claim 16 A computer program product, embodied on a non-transitory computer readable medium, the computer program product comprising: computer code which, when run on a processor, controls the processor to: calculate a gradient index as a sum of magnitudes of gradients of speech signals from a received input signal at each change of direction; provide an indication that the input signal contains babble noise when the gradient index, energy information, and background noise level exceed pre-determined thresholds or a voice activity detector algorithm and sound level indicate babble noise; and force an update of a long-term speech level estimate as a result of determining that the babble noise has been falsely indicated when a short-term speech level estimate does not reach the long-term speech level estimate for a given number of samples. ### Claim 17 (depends on 16) The computer program product of claim 16, wherein when no babble noise is indicated and the voice activity detector algorithm indicates babble noise after a period of time and the gradient index, energy information, and background noise level exceed predetermined thresholds, the computer code provides an indication that the input signal contains babble noise. ### Claim 18 (depends on 16) The computer program product of claim 16, wherein when no babble noise is indicated and the voice activity detector algorithm indicates babble noise after a period of time and the gradient index, energy information, and background noise level do not exceed pre-determined thresholds, the computer code waits a time, updates the input signal, and checks for babble noise in the updated input signal. ### Claim 19 (depends on 18) The computer program product of claim 18, wherein the computer code further controls the processor to filter the gradient index and energy information.