US 11,961,529 B2
Hybrid expansive frequency compression for enhancing speech perception for individuals with high-frequency hearing loss
Joshua Michael Alexander, Lafayette, IN (US)
Assigned to Purdue Research Foundation, West Lafayette, IN (US)
Filed by Purdue Research Foundation, West Lafayette, IN (US)
Filed on May 17, 2022, as Appl. No. 17/746,067.
Claims priority of provisional application 63/189,235, filed on May 17, 2021.
Prior Publication US 2022/0366921 A1, Nov. 17, 2022
Int. Cl. G10L 19/02 (2013.01); G10L 19/20 (2013.01); G10L 25/18 (2013.01); G10L 25/21 (2013.01)
CPC G10L 19/0208 (2013.01) [G10L 19/20 (2013.01); G10L 25/18 (2013.01); G10L 25/21 (2013.01)] 19 Claims
OG exemplary drawing
 
1. A method of audio signal processing comprising:
(a) receiving an audio signal input via a digital signal processor, wherein the audio signal input includes a speech sound;
(b) detecting a high-frequency energy of the speech sound via a detector of the digital signal processor to determine whether frication is present in the audio signal input;
(c) when frication is present in the audio signal input, classifying the audio signal input into two or more speech sound classes, wherein the classification of the audio signal input includes:
A) comparing a band-pass filtered energy of the audio signal input to a high-pass filtered energy of the audio signal input via the digital signal processor;
B) selecting a form of the input-dependent frequency remapping function based on the comparison of the hand-pass filtered enercw and the high-pass filtered energy, wherein the form of the input-dependent frequency remapping function is at least one of:
(i) compressive in the mid frequencies and expansive in the high frequencies, or
(ii) expansive in the mid frequencies and compressive in the high frequencies; and
C) selecting an expansive compression ratio (ECR) based on the selected form of input-dependent frequency remapping function;
(d) upon classifying the audio signal input into two or more speech sound classes, initiating a Hybrid Expansive Frequency Compression (hEFC), wherein the hEFC includes re-coding one or more input frequencies of the speech sound via an input-dependent frequency remapping function to generate one or more output frequencies, wherein the output frequencies are at least one of:
(A) first compressive and then expansive, or
(B) first expansive and then compressive; and
(e) generating an output signal from the output frequencies, wherein the output signal is a representation of the audio signal input having a decreased sound frequency.