FIELD OF THE INVENTION

The present invention relates to a hearing aid, and more particularly to a self-adaptive adjustment method and a hearing aid using the self-adaptive adjustment method.

BACKGROUND OF THE INVENTION

In terms of adaptation, hearing aids are mainly divided into two types, including programmable hearing aids and non-programmable hearing aids. In accordance with the non-programmable hearing aid, hearing loss parameters are burnt into the hearing aids according to the preset degree of hearing loss, and a more suitable hearing aid is selected through the speech banana area of the patient's audiogram. The self-adaptive part of the non-programmable hearing aid is mainly based on a low-pass filter button, a high-pass filter button and a band-pass filter button of the non-programmable hearing aid, and supplemented by a total volume adjustment button as an adjustment system.

In accordance with the programmable hearing aid, the patient's audiogram is converted into corresponding signatures (for example, NAL-NL2 matching formula) as audio adjustment parameters through adaptation software by the audiologist, and the audio adjustment parameters are stored into a wide dynamic range compression (WDRC) device of the programmable hearing aid through a burning process. The main function of the WDRC device is to increase the volume gain value of the input audio signal with a low volume to facilitate identification, and to reduce the volume gain value of the input audio signal with a large volume to avoid discomfort caused by too much sound. Moreover, when the volume of the output audio signal exceeds the range that the human ears can load, the WDRC device enables a maximum power output (MPO) limit function to limit the volume within a certain range in order to protect the ears from hearing damage. Moreover, the self-adaptive part of the programmable hearing aid is operated by using APP or the multi-channel equalizer button of the programmable hearing aid in cooperation with the total volume adjustment button as an adjustment system. In comparison with non-programmable hearing aids, programmable hearing aids have the advantages of wider applicability and the ability to adjust hearing aids at any time according to the changes of the user's hearing loss.

Please refer toFIGS. 1 and 2.FIG. 1is a schematic diagram illustrating the relationship between the input audio signal and the output audio signal of a conventional control-output compression-type programmable hearing aid when the wide dynamic range compression is performed at three set output volume levels.FIG. 2is a schematic diagram illustrating the relationship between the input audio signal and the basic gain of the control-output compression-type programmable hearing aid as shown inFIG. 1.

Generally, when a hearing aid is worn on a user, the hearing attenuation curve of the user is compensated for different gains at different frequencies. InFIGS. 1 and 2, the relationship between the input audio signal and the output audio signal, and the relationship between the input audio signal and the basic gain are obtained at a specified frequency. If the user adjusts the output volume of the hearing aid to different set output volume levels, there are different conversion curves at this frequency. For example, inFIGS. 1 and 2, three curves A, B and C corresponding to three different set output volume levels are shown. The curve A represents that the set output volume level of the hearing aid is adjusted to the maximum volume level. The curve B represents that the set output volume level of the hearing aid is reduced by 10 dB SPL from the maximum volume level. The curve C represents that the set output volume level of the hearing aid is reduced by 20 dB SPL from the maximum volume level. Conventionally, the audio adjustment parameters corresponding to one of the three curves A, B and C can be pre-recorded in the hearing aid. For example, the audio adjustment parameters corresponding to the curve B are pre-recorded in the hearing aid, and the audio adjustment parameters corresponding to the other curves can be calculated according to the pre-recorded audio adjustment parameters.

A conventional operating method of an automatic gain control-output (AGC-o) compression-type programmable hearing aid will be described as follows. Firstly, the basic gain value is calculated according to the volume compression threshold (or knee point), the compression ratio, g50 (i.e., the gain value of the input audio signal at 50 dB SPL), g65, g80 and other appropriate audio adjustment parameters, which is included in the corresponding signatures converted from the patient's audiogram. As the sound volume is increased or decreased, a fixed output compression method is used to drive the compressor to compress the sound. For example, in the curves A, B and C, the compression ratio of the input level to the output level is 1:1 when the output volume level is lower than 90 dB SPL, and the compression ratio of the input level to the output level is 2:1 when the output volume level reaches 90 dB SPL. Consequently, the knee points for the curves A, B and C are different. For example, the knee point for the curve A occurs at the input audio signal of 40 dB SPL (i.e., the volume compression threshold is 40 dB SPL), the knee point for the curve B occurs at the input audio signal of 50 dB SPL (i.e., the volume compression threshold is 50 dB SPL), and the knee point for the curve C occurs at the input audio signal of 60 dB SPL (i.e., the volume compression threshold is 60 dB SPL).

As described inFIGS. 1 and 2, the volume compression threshold in the audio adjustment parameters is actually set according to whether the output audio signal reaches the set threshold. Since the set thresholds for output audio signals at different set output volume levels are identical (e.g., 90 dB SPL for the curves A, B and C ofFIG. 1), some drawbacks occur. For example, when the user adjusts the sound volume through the APP or the buttons of the hearing aid to increase the volume, it is easy to frequently enable the maximum power output (MPO) limiting function, and the instantaneous loud volume is over-amplified to cause discomfort to the user. When the volume is decreased, the sound dynamic range is lost. Moreover, when the volume is increased or decreased, it is necessary to re-adjust g50, g65 and g80 to calculate the adjusted wide dynamic range compression gain value. Due to the high calculation result, the production cost of the conventional hearing aid is higher.

Therefore, there is a need of providing a self-adaptive adjustment method and a hearing aid using the self-adaptive adjustment method in order to overcome the drawbacks of the conventional technologies.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a self-adaptive adjustment method and a hearing aid using the self-adaptive adjustment method. When the user adjusts the sound volume, it is not necessary to frequently enable the maximum power output (MPO) limiting function, and the instantaneous loud volume is not over-amplified to cause discomfort to the user. In addition, the sound dynamic range is wider, and the production cost of the hearing aid is reduced.

In accordance with an aspect of the present invention, a self-adaptive adjustment method for a hearing aid is provided. At least one audio adjustment parameter is previously stored in the hearing aid. The at least one audio adjustment parameter includes a first audio compression rate, a second audio compression rate and a preset volume compression threshold. The preset volume compression threshold is adapted as a set output volume level is equal to a default volume level of the hearing aid. The self-adaptive adjustment method includes the steps of: (S1) receiving an external sound source, and converting the external sound source into an input audio signal; (S2) converting the input audio signal into a first output audio signal at a first audio compression rate, and converting the first output audio signal into an output sound source, wherein a first gain value exists between the first output audio signal and the input audio signal; (S3) determining a relative relation between the set output volume level and the default volume level of the hearing aid, wherein when the determining result indicates that an offset value is formed between the set output volume level and the default volume level, calculates a dynamic volume compression threshold according to the preset volume compression threshold, the second audio compression ratio and the offset value, and compares and determines whether the volume of the input audio signal is greater than the dynamic volume compression threshold; and (S4) converting the input audio signal into a second output audio signal at a second audio compression rate, and converting the second output audio signal into the output sound source, wherein a second gain value exists between the second output audio signal and the input audio signal. When the determining result of the step (S3) indicates that the volume of the input audio signal is higher than the dynamic volume compression threshold, the step (S4) is performed, and when the determining result of the step (S3) indicates that the volume of input audio signal is lower than or equal to the dynamic volume compression threshold, the step (S2) is repeatedly done.

The above contents of the present invention will become more readily apparent to those ordinarily skilled in the art after reviewing the following detailed description and accompanying drawings, in which:

