Method for optimizing echo double talk in reflection environment, mobile terminal and storage medium

Abstract

The invention relates to the technical field of audio processing, and discloses a method for optimizing echo double talks in a reflection environment, a mobile terminal and a storage medium, the method comprises the following steps: in a hand-free call process, controlling a motor to vibrate for a preset duration; collecting a vibration signal generated by vibration of the motor; comparing the collected vibration signal with a preset reflection environment characteristic signal; and selecting an audio parameter according to a comparison result. By acquiring amplitude characteristics and / or spectrum characteristics of the vibration signals for comparison, a hard reflecting surface and a soft reflecting surface can be distinguished, and corresponding optimized audio parameters are selected. According to the method, the motor and the microphone of the mobile terminal are utilized, hardware cost does not need to be increased, whether the mobile terminal is in the reflection environment or not can be detected, the audio parameters are dynamically adjusted according to the detection result, the echo double-talk effect in the reflection environment is equivalent to that in a handheld scene, and the hand-free call quality is remarkably improved.

Description

Methods for optimizing echo double-talk in reflective environments, mobile terminals, and storage media Technical Field

[0001] This invention relates to the field of audio processing technology, and in particular to a method for optimizing echo double talk in a reflective environment, a mobile terminal, and a storage medium. Background Technology

[0002] With the development of mobile communication technology, mobile terminals such as smartphones and tablets have become indispensable communication tools in people's daily lives. Applications such as live internet calling and VoIP network calling are becoming increasingly popular, and call quality has become one of the core factors affecting user experience. Among these, echo double-talk is a relatively common and significant technical problem in hands-free calling on mobile terminals.

[0003] When a mobile terminal operates in hands-free mode, the speaker volume is relatively high, causing the downlink signal to be picked up by the microphone through the air, creating an echo signal that couples into the uplink channel. To eliminate this echo, mobile terminals typically employ strong echo suppression algorithms. However, while strong echo suppression eliminates the echo, it can also suppress the voice signal of the near-end user, leading to a deterioration in hands-free two-way communication, manifesting as suppressed near-end voice, intermittent or stuttering speech.

[0004] For mobile terminals using a single microphone, the echo double-talk problem is particularly prominent. Because the physical distance between the microphone and the speaker is relatively short, the echo signal picked up by the microphone is stronger, which requires the echo suppression algorithm to have a stronger suppression intensity, thus exacerbating the false suppression of near-end speech.

[0005] Existing echo cancellation technologies primarily rely on adaptive filtering algorithms, which estimate and eliminate echoes by establishing echo path models. However, these algorithms are typically based on fixed audio parameter configurations and cannot be dynamically adjusted according to the actual acoustic environment of the mobile terminal. In practical applications, audio engineers often fine-tune audio parameters while holding the mobile terminal to achieve good echo-through performance in handheld scenarios. But when users place the mobile terminal on a reflective surface, the acoustic environment changes significantly, and the original parameter configurations become unsuitable for the new environment, leading to problems such as echo trailing sounds and reduced 2D communication performance.

[0006] While most mainstream mobile platforms are equipped with echo suppression algorithms, these algorithms still suffer from issues such as excessive dual-talk suppression, voice stuttering, and intermittent speech when faced with varying reflective environments. Current technology lacks effective means to automatically detect whether a mobile terminal is in a strong reflective environment, and it cannot dynamically adjust audio processing parameters based on detection results to optimize echo dual-talk performance. This makes it difficult to maintain consistent call quality across different usage scenarios, negatively impacting the user's call experience. Summary of the Invention

[0007] The purpose of this invention is to provide a method, mobile terminal, and storage medium for optimizing echo double-talk in a reflective environment, so as to solve the problem of poor echo double-talk effect of mobile terminals in reflective environments in the prior art.

[0008] To address the aforementioned technical problems, this invention provides a method for optimizing echo two-way communication in a reflective environment, comprising: controlling a motor to vibrate for a preset duration during hands-free calling; acquiring vibration signals generated by the motor vibration; comparing the acquired vibration signals with preset reflective environment characteristic signals; and selecting audio parameters based on the comparison results.

[0009] Optionally, controlling the motor to vibrate for a preset duration during a hands-free call includes: controlling the motor to vibrate for the preset duration when the hands-free call begins; and / or controlling the motor to vibrate for the preset duration when movement is detected during the hands-free call.

[0010] Optionally, the process of controlling the motor to vibrate for the preset duration when starting a hands-free call includes: muting the hands-free downlink signal when starting a hands-free call; controlling the motor to vibrate for the preset duration during the downlink signal muting period; and restoring the hands-free downlink signal after the motor stops vibrating; and / or the process of controlling the motor to vibrate for the preset duration when movement is detected during a hands-free call includes: monitoring movement via an accelerometer; and controlling the motor to vibrate for the preset duration after the movement ends when movement that meets preset movement conditions is detected.

[0011] Optionally, the process of comparing the acquired vibration signal with a preset reflection environment feature signal includes: acquiring the signal features of the vibration signal, and comparing the signal features of the vibration signal with the signal features of the preset reflection environment feature signal; preferably, the signal features include amplitude features and / or spectral features, the amplitude features include the root mean square (RMS) value, and the spectral features include low-frequency band features and / or high-frequency band features; preferably, the process of comparing the signal features of the vibration signal with the signal features of the preset reflection environment feature signal includes: calculating the difference or similarity between the signal features of the vibration signal and the signal features of the preset reflection environment feature signal; when the difference is less than a preset difference threshold or the similarity is greater than a preset similarity threshold, it is determined that the vibration signal matches the preset reflection environment feature signal.

[0012] Optionally, the preset reflective environment characteristic signal includes a first reflective surface characteristic signal and a second reflective surface characteristic signal; preferably, the step of selecting audio parameters based on the comparison result includes: when the vibration signal matches the first reflective surface characteristic signal, selecting a first audio parameter optimized for the first reflective surface; when the vibration signal matches the second reflective surface characteristic signal, selecting a second audio parameter optimized for the second reflective surface; and when the vibration signal does not match either the first or second reflective surface characteristic signal, selecting a default audio parameter; preferably, the amplitude characteristic of the first reflective surface characteristic signal is higher than the amplitude characteristic of the second reflective surface characteristic signal; more preferably, the parameter adjustment amount of the first audio parameter optimized for the first reflective surface is greater than the parameter adjustment amount of the second audio parameter optimized for the second reflective surface.

[0013] Optionally, the first audio parameter optimized for the first reflective surface or the second audio parameter optimized for the second reflective surface may be adjusted relative to the default audio parameter by at least one of the following: reducing the gain of the echo cancellation algorithm; increasing the gain of the noise reduction algorithm; or adjusting the equalizer parameters.

[0014] Optionally, adjusting the equalizer parameters includes: performing low-frequency attenuation on the equalizer for the uplink signal; and performing low-frequency compensation on the equalizer for the downlink signal to compensate for the low-frequency attenuation of the uplink signal. Preferably, the amount by which the gain of the echo cancellation algorithm is reduced is equal to the amount by which the gain of the noise reduction algorithm is increased. More preferably, the amount by which the gain of the echo cancellation algorithm is reduced is 3dB to 8dB, and the amount by which the gain of the noise reduction algorithm is increased is 3dB to 8dB.

[0015] The present invention also provides a mobile terminal, comprising: a motor; a microphone; and a processor; wherein the processor is configured to: control the motor to vibrate for a preset duration during hands-free calling; acquire vibration signals generated by the motor vibration collected by the microphone; compare the acquired vibration signals with preset environmental reflection feature signals; and select audio parameters based on the comparison results.

[0016] Optionally, an acceleration sensor is also included; the processor is used to monitor movement through the acceleration sensor, and when movement that meets preset movement conditions is detected, the processor controls the motor to vibrate for the preset duration after the movement ends.

[0017] The present invention also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the method for optimizing echo double talk in a reflective environment as described above.

[0018] Compared to existing technologies, this invention offers at least the following technical advantages: The method for optimizing echo two-way communication in reflective environments provided by this invention controls motor vibration and collects the generated vibration signals during hands-free calling. These vibration signals are then compared with preset reflective environment characteristic signals to determine whether the mobile terminal is in a reflective environment. Based on the comparison results, appropriate audio parameters are selected, achieving automatic detection of the reflective environment and dynamic adjustment of audio parameters. This method fully utilizes existing hardware resources such as the mobile terminal's built-in motor and microphone, achieving adaptive optimization for different acoustic environments without incurring additional hardware costs.

[0019] Furthermore, when the mobile terminal is placed on a highly reflective surface such as a desktop or glass surface, switching to audio parameters optimized for reflective environments can effectively improve echo and two-way communication effects, achieving call quality comparable to handheld scenarios, thus maintaining a consistent user experience across different usage scenarios. This invention achieves more refined environmental adaptation by differentiating between different types of reflective surfaces and selecting corresponding optimization parameters based on the characteristics of each surface. Through comprehensive adjustments to the echo cancellation algorithm gain, noise reduction algorithm gain, and equalizer parameters, the overall audio balance is maintained while reducing echo, avoiding near-end speech loss caused by excessive suppression. In particular, by attenuating low frequencies in the uplink equalizer and compensating accordingly in the downlink equalizer, and by ensuring that the reduction in echo cancellation gain is equal to the increase in noise reduction algorithm gain, the objective audio quality indicators are not affected while optimizing the echo two-way communication effect in reflective environments, achieving a dual improvement in subjective experience and objective performance. Attached Figure Description

[0020] Figure 1 is a comparison diagram of echo signals in an embodiment of the present invention; Figure 2 is a comparison diagram of echo signals in an embodiment of the present invention; Figure 3 is a block diagram of the method steps for optimizing echo double-talk under reflection environment in an embodiment of the present invention; Figure 4 is a schematic diagram of the mobile terminal structure in an embodiment of the present invention; Figure 5 is a flowchart of the method steps for optimizing echo double-talk under reflection environment in an embodiment of the present invention; Figure 6 is a waveform diagram of motor vibration signal in an embodiment of the present invention; Figure 7 is a comparison diagram of motor vibration signal spectrum in an embodiment of the present invention; Figure 8 is a waveform diagram of motor vibration signal in an embodiment of the present invention; Figure 9 is a comparison diagram of motor vibration signal spectrum in an embodiment of the present invention; Figure 10 is a flowchart of audio processing in an embodiment of the present invention.

[0021] In the picture, 1 is the upper speaker; 2 is the microphone; 3 is the USB port; 4 is the lower speaker; and 5 is the motor. Detailed Implementation

[0022] The following description, with reference to schematic diagrams, illustrates a method for optimizing echo double-talk in a reflective environment, a mobile terminal, and a storage medium according to the present invention. Preferred embodiments of the invention are shown. It should be understood that those skilled in the art can modify the invention described herein while still achieving its advantageous effects. Therefore, the following description should be understood as being of general knowledge to those skilled in the art and is not intended to limit the invention.

[0023] Based on the teachings of this specification, those skilled in the art can form new technical solutions by combining different implementation methods without creating technical contradictions. Such variations should be considered to fall within the protection scope of this application.

[0024] The invention is described more specifically by way of example in the following paragraphs with reference to the accompanying drawings. The advantages and features of the invention will become clearer from the following description. It should be noted that the drawings are in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the invention.

[0025] In Example 1, the applicant discovered that when a mobile terminal is placed on a hard reflective surface, the reflective environment significantly affects the echo signal. To verify this phenomenon, the following experiment was conducted: The mobile terminal was held in hand (position H) and placed on a table (position S1), and a voice service call was made once each time. The echo signal was collected through the microphone. As shown in Figure 1, the left channel is the echo signal collected by the microphone at position H, and the right channel is the echo signal collected by the microphone at position S1 when the terminal is placed on the table. As shown in Figure 1, the echo signal collected by the microphone when the terminal is placed on the table is 5.61 dB higher than that when the terminal is held in hand.

[0026] When a mobile terminal is placed on a hard reflective surface such as a desktop, marble surface, or glass surface, the sound wave propagation path of the speaker consists of two parts: one part of the sound wave propagates directly to the microphone, and the other part of the sound wave propagates to the reflective surface, is reflected, and then propagates to the microphone. Because the hard reflective surface has a large acoustic impedance and a high reflection coefficient, the reflected sound wave and the directly propagated sound wave are superimposed at the microphone, resulting in a significant increase in the intensity of the echo signal collected by the microphone.

[0027] Similar experiments were conducted on soft reflective surfaces. The mobile terminal was held in hand and placed on a sofa (position S2), and a service call was made once each time. As shown in Figure 2, the left channel represents the echo signal collected by the microphone when the phone is held (position H), and the right channel represents the echo signal collected by the microphone when the phone is placed on the sofa (position S2). Figure 2 shows that when placed at position S2, the echo signal collected by the microphone is 3.74 dB higher than when held in hand. This enhancement is 1.87 dB lower than at position S1, i.e., on the hard reflective surface. This is because soft materials such as sofas have a porous structure and strong sound absorption characteristics, resulting in a lower reflection coefficient for sound waves compared to hard materials. Therefore, the reflected sound wave energy is weaker, and the superposition effect is less significant than on a hard reflective surface.

[0028] The experimental results revealed the differences in echo signal strength of mobile terminals under different usage environments. This difference explains a typical problem in actual use: when audio engineers adjust audio parameters using handheld mobile terminals, they can achieve good echo suppression and dual-talk performance with no obvious echo and acceptable dual-talk; however, when users place the mobile terminal on a reflective surface such as a desktop, the increased echo signal strength means that the original parameter configuration cannot adequately suppress the enhanced echo, leading to problems such as echo tails and decreased dual-talk performance.

[0029] Based on the above findings, this embodiment provides a method for optimizing the echo two-way communication effect in a reflective environment, as shown in Figure 3, including the following steps: S1, during hands-free calling, controlling the motor vibration for a preset duration; S2, collecting the vibration signal generated by the motor vibration; S3, comparing the collected vibration signal with a preset reflective environment characteristic signal; S4, selecting audio parameters based on the comparison result.

[0030] The method provided in this embodiment is applied to hands-free calling scenarios on mobile terminals. The mobile terminal can be an electronic device with hands-free calling capabilities, such as a mobile phone or tablet computer. As shown in Figure 4, the mobile terminal includes an upper speaker 1, a microphone 2, a USB interface 3, a lower speaker 4, and a motor 5.

[0031] In step S1, the hands-free calling process includes the start phase of the hands-free call and any specific moment during the hands-free call process.

[0032] The preset duration refers to the length of time that the motor 5 continuously vibrates. In a specific example, the preset duration is less than 500 milliseconds. Preferably, the preset duration is between 200 and 500 milliseconds, and more preferably around 300 milliseconds.

[0033] In a specific example, setting the preset duration to within 500 milliseconds can ensure that enough vibration signals are collected for environmental assessment while avoiding excessively long motor vibration time that could negatively impact user experience or be noticeably perceived by the user.

[0034] The vibration intensity of the motor 5 should be set within a range that is not easily perceived by the user or is acceptable. In a specific example, by adjusting the drive voltage or current of the motor 5, the vibration intensity is controlled below or just at the tactile threshold, so that the user will not notice or be disturbed by the vibration during normal use.

[0035] In step S1, the specific implementation methods include the following two: Method 1: When the hands-free call starts, control the motor to vibrate for the preset duration.

[0036] The environment detection is automatically triggered when the user switches to hands-free mode or starts a hands-free call. The specific process is as follows: When the user is detected to have activated the hands-free call function, for example, when the user clicks the hands-free button or starts hands-free mode via voice command, the mobile terminal's processor immediately executes the environment detection process.

[0037] In order to avoid affecting the call during motor vibration, in a preferred embodiment, the process includes: S111, muting the hands-free downlink signal when the hands-free call begins.

[0038] S112. During the downlink signal silence period, control the motor to vibrate for the preset duration.

[0039] S113. After the motor stops vibrating, restore the hands-free downlink signal.

[0040] The hands-free downlink signal refers to the voice signal of the other party played from the speaker (lower speaker 4 and / or upper speaker 1). Mute the downlink signal to avoid the sound played from the speaker interfering with the microphone 2's acquisition of the motor vibration signal during motor vibration and signal acquisition, ensuring that the acquired signal mainly comes from motor vibration rather than speaker playback.

[0041] In step S111, in a specific example, before muting the hands-free downlink signal, the energy of the hands-free downlink signal is detected. When the energy of the downlink signal is lower than a preset energy threshold, for example, lower than -40dBFS or -50dBFS, it indicates that the other party is not speaking or the voice energy is weak. In this case, performing the muting operation will not cause the user to miss important information. If the downlink signal energy is high, the detection process can be delayed, waiting for the downlink signal energy to decrease before triggering, or the delay can be recorded in the background and the detection can be retried at an appropriate time.

[0042] In step S1112, after the downlink signal is muted, the motor 5 is immediately controlled to start vibrating. The duration of the vibration is the preset duration. During the vibration, the microphone 2 continuously collects the vibration signal generated by the motor vibration.

[0043] In one specific example, the downlink signal is muted for the same duration as the preset duration of the motor vibration, ensuring that the downlink signal remains muted throughout the entire motor vibration period. For example, if the preset duration is 300 milliseconds, the downlink signal is also muted for 300 milliseconds.

[0044] In step S113, once motor 5 stops vibrating and signal acquisition is complete, the playback of the hands-free downlink signal is immediately restored, causing the speaker to replay the other party's voice. The entire process from mute to restoration is typically completed within 500 milliseconds, with minimal impact on the call; the user will hardly perceive the brief silence.

[0045] Method 2: When movement is detected during a hands-free call, the motor is controlled to vibrate for the preset duration.

[0046] In this specific example, this is a passive triggering method used to address situations where the user changes the placement of the mobile terminal during a hands-free call. For example, the user initially holds the mobile terminal in their hand for a hands-free call, then places it on a table during the call; or vice versa, initially placing it on a table and then picking it up to hold. This change in placement will cause a change in the acoustic environment, requiring re-detection and adjustment of audio parameters. The specific process is as follows: S121, Detect movement using an accelerometer.

[0047] S122. When a movement that meets the preset movement conditions is detected, the motor is controlled to vibrate for the preset duration after the movement ends.

[0048] In step S121, the mobile terminal has a built-in accelerometer sensor that can monitor the acceleration changes of the mobile terminal in three-dimensional space in real time. The processor continuously reads the data from the accelerometer sensor and analyzes the motion state of the mobile terminal.

[0049] In step S122, the preset movement condition is used to filter out minor, accidental movements and only respond to meaningful movements that may cause a change in the placement state. In a specific example, the preset movement condition includes at least one of the following: (1) Movement duration threshold: the duration of the movement reaches a certain threshold, such as 1 second, 2 seconds, or 3 seconds or more. Movements that are too short, such as slight shaking, will not trigger detection.

[0050] (2) Acceleration threshold: The magnitude of the acceleration change reaches a certain threshold, such as an acceleration change exceeding 0.3g, 0.5g or 1g. Too small an acceleration change will not trigger detection.

[0051] (3) Movement distance estimation: The movement distance is estimated based on the double integral of acceleration. It is triggered when the movement distance exceeds a certain threshold, such as 10 cm or 20 cm.

[0052] (4) Posture change: A significant change in the spatial posture of the mobile terminal is detected, such as changing from a vertical state to a horizontal state, or an angle change of more than 30 degrees or 45 degrees.

[0053] When the motion detected by the accelerometer meets one or more of the above conditions, it is determined that a valid movement has occurred that may lead to a change in the placement state.

[0054] The processor further determines whether the movement has ended. The determination condition for the end of the movement can be: the acceleration returns to a stationary state, for example, the change in acceleration is less than a threshold and lasts for a certain period of time, such as 0.5 seconds or 1 second, indicating that the mobile terminal has been placed stably.

[0055] After the movement ends, the processor controls motor 5 to vibrate for the preset duration to re-detect the current acoustic environment. In a specific example, during motor vibration, the hands-free downlink signal is also muted, employing a mute-vibration-recovery process similar to Method 1 to ensure the accuracy of signal acquisition.

[0056] Please refer to Figure 5. Preferably, by combining Method 1 and Method 2, the environment can be actively detected at the start of a hands-free call and respond to environmental changes during the call, achieving adaptive optimization throughout the entire process.

[0057] Further, in step S2, the vibration signal generated by the motor vibration is acquired. During the vibration of the motor 5, the microphone 2 continuously acquires the acoustic vibration signal generated by the motor vibration. The vibration signal propagates through the air to reach the microphone 2 and is converted into an electrical signal by the microphone 2. The sampling rate of the microphone 2 should be high enough to capture the spectral characteristics of the vibration signal. In a specific example, the sampling rate is 16kHz, 24kHz, 48kHz or higher to ensure accurate acquisition of the low-frequency and high-frequency components of the vibration signal.

[0058] The duration of the collected vibration signal is consistent with the preset duration. For example, if the motor vibrates for 300 milliseconds, then microphone 2 collects 300 milliseconds of audio data.

[0059] Furthermore, three placement positions are defined: position H is when the mobile terminal is held in the hand (Hand-held), position S1 is when the mobile terminal is placed on a hard reflective surface (such as a wooden tabletop, glass tabletop, etc.), and position S2 is when the mobile terminal is placed on a soft reflective surface (such as a sofa, fabric, etc.).

[0060] When motor 5 vibrates, microphone 2 is used to pick up the vibration signal of motor 5. The comparative experimental results for positions H and S1 are shown in Figure 6, where the first four signals are vibration signals picked up by the mobile terminal at position H, and the last four signals are vibration signals picked up by the mobile terminal at position S1. In terms of amplitude characteristics, the average RMS amplitude of the signal collected at position H is -59.09 dB, while the average RMS amplitude of the signal collected at position S1 is -52.84 dB, with the RMS amplitude at position S1 increasing by approximately 6.25 dB compared to position H. In terms of spectral characteristics, as shown in Figure 7, the energy of the vibration signal picked up at position S1 is significantly higher than that picked up at position H in both the low-frequency and high-frequency bands.

[0061] The comparative experimental results for positions H and S2 are shown in Figure 8. The first two signals are vibration signals picked up by the mobile terminal when it is at position H, and the latter two signals are vibration signals picked up by the mobile terminal when it is at position S2. In terms of amplitude characteristics, the average RMS amplitude of the signal collected at position H is -58.89 dB, while the average RMS amplitude of the signal collected at position S2 is -42.73 dB, representing an increase of approximately 16.16 dB in RMS amplitude compared to position H. In terms of spectral characteristics, as shown in Figure 9, the energy of the vibration signal picked up at position S2 is significantly higher than that picked up at position H in both the low-frequency and high-frequency bands.

[0062] Based on the above physical mechanism, by analyzing the amplitude and spectral characteristics of the vibration signal collected by microphone 2, it is possible to determine whether the mobile terminal is in a reflective environment and the nature of the reflective surface.

[0063] The vibration signal characteristics of the motor corresponding to different placement positions are preset within the mobile terminal. Specifically, the vibration signal characteristics corresponding to the preset position S1 (hard reflective surface) include its typical RMS amplitude range and spectrum characteristics; the vibration signal characteristics corresponding to the preset position S2 (soft reflective surface) include its typical RMS amplitude range and spectrum characteristics. When the mobile terminal is actually working, the signal generated by the vibration of the motor 5 is picked up by the microphone 2, and its amplitude and spectrum characteristics are extracted and compared with the characteristic signals of the preset positions S1 and S2. When the actual picked-up signal matches the characteristic signal of the preset position S1 in amplitude and spectrum, it is determined that the mobile terminal is currently in position S1, i.e., placed on the hard reflective surface; when the actual picked-up signal matches the characteristic signal of the preset position S2 in amplitude and spectrum, it is determined that the mobile terminal is currently in position S2, i.e., placed on the soft reflective surface; when the actual picked-up signal does not match the characteristic signal of either position S1 or position S2, it is determined that the mobile terminal is currently in position H, i.e., in a handheld state.

[0064] In a specific example, to improve the reliability of detection, multiple acquisitions and comparisons can be used. For instance, during the vibration of motor 5, the acquired signal is divided into multiple time windows, such as one window every 100 milliseconds. The signal characteristics of each time window are analyzed separately, and finally, the analysis results of multiple windows are combined for judgment. Alternatively, motor vibration and signal acquisition can be triggered multiple times at different times, such as intervals of 10 seconds or 30 seconds. The results of multiple detections are statistically analyzed. When a certain proportion of the multiple detections, such as more than 60% or more than 3 times, is determined to be a reflective environment, the audio parameters are switched.

[0065] Furthermore, in step S3, the collected vibration signal is compared with a preset reflection environment characteristic signal.

[0066] The preset reflection environment characteristic signal is reference signal characteristic data pre-stored in the mobile terminal, representing the typical vibration signal characteristics generated by the motor vibration when the mobile terminal is in a specific reflection environment. It is obtained through extensive testing in various reflection environments, including hard reflective surfaces, soft reflective surfaces, and non-reflective environments, and is stored in the mobile terminal's memory.

[0067] In step S3, the comparison process includes: S31, acquiring the signal characteristics of the vibration signal.

[0068] Specifically, the vibration signals collected in step S2 are processed to extract their characteristic parameters.

[0069] The signal characteristics include amplitude characteristics and / or spectral characteristics.

[0070] (1) Amplitude characteristics: The amplitude characteristics are used to characterize the intensity or energy of the vibration signal. In a specific example, the amplitude characteristics include the root mean square (RMS) value.

[0071] In addition to RMS value, other amplitude characteristics, such as peak value, average amplitude, and energy, can also be used. These are common practices for those skilled in the art and will not be elaborated further.

[0072] (2) Spectral characteristics: The spectral characteristics are used to characterize the energy distribution of the vibration signal in the frequency domain. First, the collected vibration signal is subjected to spectral analysis. Commonly used methods include Fast Fourier Transform (FFT), Short-Time Fourier Transform (STFT), etc., which are well-known technologies in this field.

[0073] In one specific example, the spectral characteristics include low-frequency characteristics and / or high-frequency characteristics. The low-frequency band refers to the lower frequency portion of the vibration signal spectrum, such as 100Hz to 500Hz, 100Hz to 1kHz, or other suitable ranges. The high-frequency band refers to the higher frequency portion of the vibration signal spectrum, such as 2kHz to 8kHz, 2kHz to 10kHz, or other suitable ranges.

[0074] As shown in Figures 7 and 9, when placed on a reflective surface, the energy of the vibration signal in both the low-frequency and high-frequency bands is higher than when held in hand. This spectral difference can be used as a basis for judging the reflective environment.

[0075] Furthermore, step S3 also includes step S32, comparing the signal characteristics of the vibration signal with the signal characteristics of the preset reflection environment characteristic signal.

[0076] The preset reflection environment characteristic signal also contains corresponding signal characteristics. The comparison process involves comparing the characteristics of the current vibration signal extracted in step S31 with the preset characteristics.

[0077] In a specific example, the comparison process specifically includes: calculating the difference or similarity between the signal characteristics of the vibration signal and the signal characteristics of the preset reflection environment characteristic signal.

[0078] Specifically, for amplitude features, the difference between the two can be calculated; for spectral features, the distance or similarity between spectral vectors can be calculated. Commonly used methods include Euclidean distance, cosine similarity, and cross-correlation coefficients. For example, multiple spectral parameters such as low-frequency energy and high-frequency energy can be combined to form a feature vector, and the Euclidean distance between the feature vector of the current signal and a preset feature vector can be calculated.

[0079] Furthermore, when the difference is less than a preset difference threshold or the similarity is greater than a preset similarity threshold, it is determined that the vibration signal matches the preset reflection environment feature signal.

[0080] The preset difference threshold and preset similarity threshold are judgment criteria set based on experimental data and experience.

[0081] For example, for amplitude characteristics, a preset difference threshold of 2dB is set. If the calculated RMS difference Δ is less than 2dB, the amplitude characteristics of the current vibration signal are considered to match the preset reflection environment characteristic signal; if Δ is greater than or equal to 2dB, it is considered not to match.

[0082] For spectral similarity, a preset similarity threshold is set to 0.8 or 0.9. If the calculated cosine similarity is greater than 0.8, the spectral features are considered to match; otherwise, they are not considered to match.

[0083] Furthermore, a judgment can be made by combining the matching results of amplitude features and spectral features.

[0084] In a specific example, an overall match is determined only when both the amplitude feature and the spectral feature match. Alternatively, a weighted synthesis method can be used, assigning different weights to the amplitude feature and the spectral feature to calculate the overall match degree.

[0085] Furthermore, regarding the distinction between reflective surface types in this embodiment: In a preferred implementation, the preset reflective environment characteristic signal includes a first reflective surface characteristic signal and a second reflective surface characteristic signal. The first reflective surface and the second reflective surface represent reflective environments of different natures.

[0086] In a specific example, the first reflective surface is a hard reflective surface, such as a wooden tabletop, glass surface, marble surface, or metal surface—surfaces with high rigidity and strong reflectivity. The second reflective surface is a soft reflective surface, such as a sofa, fabric surface, or mattress surface—soft surfaces with sound-absorbing and damping properties.

[0087] In this embodiment, the RMS value range of the characteristic signal of the first reflective surface (hard surface) can be set to -55dB to -50dB; and the RMS value range of the characteristic signal of the second reflective surface (soft surface) can be set to -48dB to -40dB.

[0088] The energy distribution of the characteristic signal of the first reflecting surface is different from that of the second reflecting surface in the low-frequency and high-frequency bands. The corresponding spectral feature template can be established based on experimental data.

[0089] During the comparison, the matching degree between the current vibration signal and the characteristic signal of the first reflecting surface, and the matching degree with the characteristic signal of the second reflecting surface are calculated respectively, and the one with the highest matching degree is selected as the judgment result.

[0090] Furthermore, in step S4, audio parameters are selected based on the comparison results.

[0091] Specifically, based on the comparison results in step S3, the processor selects the corresponding audio parameters for subsequent hands-free call audio processing.

[0092] In one specific implementation, selecting audio parameters based on the comparison results specifically includes: when the vibration signal matches the characteristic signal of the first reflective surface, selecting a first audio parameter optimized for the first reflective surface.

[0093] When it is determined that the mobile terminal is placed on a hard reflective surface, the first audio parameter is selected. The first audio parameter is a parameter configuration optimized for echo signal enhancement in hard reflective environments.

[0094] When the vibration signal matches the characteristic signal of the second reflective surface, a second audio parameter optimized for the second reflective surface is selected.

[0095] When it is determined that the mobile terminal is placed on a soft reflective surface, the second audio parameter is selected. The second audio parameter is a parameter configuration specifically for soft reflective environments, and its optimization intensity is relatively light.

[0096] When the vibration signal does not match either the first reflective surface feature signal or the second reflective surface feature signal, the default audio parameters are selected.

[0097] When it is determined that the mobile terminal is not in a significant reflective environment (e.g., handheld), the default audio parameters are selected. The default audio parameters are the standard parameter configuration used by the mobile terminal at the factory or in a normal non-reflective environment, and this configuration can provide good echo two-way communication effect in handheld scenarios.

[0098] Furthermore, regarding the adjustment of audio parameters: the first and second audio parameters have been specifically adjusted relative to the default audio parameters to address the issue of enhanced echo signals in reflective environments.

[0099] The adjustment includes at least one of the following: (a) reducing the gain of the echo cancellation algorithm.

[0100] Acoustic Echo Cancellation (AEC) algorithms model echo paths using adaptive filters to estimate and eliminate echo signals. In reflective environments, due to the amplification of echo signals, using the original echo cancellation gain may over-suppress echoes and also mistakenly suppress near-end speech, resulting in poor two-way speech performance.

[0101] By reducing the gain of the echo cancellation algorithm, the suppression intensity on the signal is lessened, which can reduce false suppression of near-end speech and improve the two-way speech effect. In Figure 10, position A represents the gain control of the echo cancellation algorithm. For reflection environments, the gain at this point is reduced by n dB.

[0102] In a specific example, the gain reduction of the echo cancellation algorithm is 2dB to 8dB. For example, for a hard reflector, the reduction n1 can be set to 4dB to 8dB; for a soft reflector, the reduction n2 can be set to 2dB to 6dB.

[0103] (b) Increase the gain of the noise reduction algorithm.

[0104] Acoustic Noise Suppression (ANS) algorithms are used to suppress background noise. After reducing the echo cancellation gain, some echo signals may not be completely eliminated. By increasing the gain of the denoising algorithm, residual echoes and noise can be further suppressed, ensuring the clarity of the uplink signal.

[0105] In Figure 10, positions B and C represent the gain control of the noise reduction algorithm. For reflective environments, the gain at these positions is increased, making the noise reduction algorithm work more aggressively.

[0106] In a preferred embodiment, the amount of gain reduction in the echo cancellation algorithm is equal to the amount of gain increase in the noise reduction algorithm. That is, the gain reduction in the echo cancellation stage is compensated by the gain increase in the noise reduction stage, maintaining a relatively balanced overall signal processing intensity and avoiding over-suppression or under-suppression.

[0107] For example, if the echo cancellation gain is reduced by 5dB, the noise reduction gain is increased by 5dB. In a specific example, both the reduction and increase are between 3dB and 8dB.

[0108] This gain-balanced design optimizes the dual-talk effect without affecting the objective audio metrics of the mobile terminal, thus achieving overall performance optimization.

[0109] (c) Adjust the equalizer parameters.

[0110] An equalizer (EQ) is used to adjust the gain of a signal at different frequency bands, thereby changing the signal's spectral characteristics. In reflective environments, because the reflection and superposition of low-frequency signals are more pronounced, the spectrum can be optimized by adjusting the equalizer.

[0111] In one specific implementation, adjusting the equalizer parameters includes: attenuating the uplink signal equalizer at low frequencies: attenuating the uplink signal (including near-end speech and echo) captured by the microphone in the low-frequency range (e.g., 100Hz to 500Hz) to reduce the energy of the low-frequency echo. In Figure 10, position D represents the low-frequency attenuation setting of the uplink signal equalizer.

[0112] For example, attenuation of 3dB to 6dB in the 100Hz to 300Hz frequency band and attenuation of 2dB to 4dB in the 300Hz to 500Hz frequency band forms a low-frequency attenuation curve.

[0113] Low-frequency compensation is applied to the downlink equalizer to compensate for the low-frequency attenuation of the uplink signal: Since the low frequencies of the uplink signal are attenuated, in order to maintain the spectral balance and sound quality of the downlink signal (the other party's voice) played by the speaker, the downlink equalizer is compensated (gain boosted) in the low-frequency range. In Figure 10, position E represents the low-frequency compensation setting of the downlink equalizer.

[0114] The frequency band and amplitude of the low-frequency compensation correspond to the low-frequency attenuation of the uplink signal. For example, if the uplink signal is attenuated by 5dB between 100Hz and 300Hz, the downlink signal is boosted by 5dB in the same frequency band to ensure that the sound quality played by the speaker is not affected.

[0115] By adjusting the equalizer to attenuate the uplink and compensate the downlink, the problem of low-frequency echo in the reflection environment can be reduced, while ensuring the playback quality of the speaker, thus achieving bidirectional optimization.

[0116] Furthermore, regarding the differentiated settings for parameter adjustment: Since the reflection intensity of the first reflecting surface is greater than that of the second reflecting surface, the degree of echo enhancement is different, thus requiring differentiated parameter adjustments.

[0117] In a specific example, the parameter adjustment amount of the first audio parameter optimized for the first reflective surface is greater than the parameter adjustment amount of the second audio parameter optimized for the second reflective surface.

[0118] For example, for the hard reflector, i.e. the first reflector, the echo cancellation gain is reduced by n1 = 6dB to 8dB, the noise reduction gain is increased by 6dB to 8dB, and the low-frequency attenuation of the uplink equalizer is reduced by 5dB to 7dB.

[0119] For the soft reflector, also known as the second reflector, the echo cancellation gain is reduced by n2 = 3dB to 5dB, the noise reduction gain is increased by 3dB to 5dB, and the low-frequency attenuation of the uplink equalizer is reduced by 2dB to 4dB.

[0120] This differentiated setting ensures that an appropriate optimized intensity is applied to environments with different reflection intensities, avoiding over-adjustment or under-adjustment.

[0121] In a specific example, when it is necessary to switch from the current audio parameters to the newly selected audio parameters, a gradual transition is used to avoid audio abrupt changes or noise caused by sudden parameter changes.

[0122] For example, the transition duration can be set from 50 milliseconds to 200 milliseconds, during which various audio parameters (gain, equalizer coefficients, etc.) transition linearly or non-linearly from their current values ​​to their target values. This smooth transition is almost imperceptible to the user, enhancing the user experience.

[0123] The selected audio parameters are applied to the audio processing flow of the mobile terminal. Referring to Figure 10, the audio processing flow includes: microphone 2 acquiring signal → gain adjustment → equalizer (FIR / IIR) → echo cancellation algorithm (EC algorithm) → gain adjustment → noise reduction algorithm (ANS algorithm) → gain adjustment → equalizer (FIR / IIR) → output.

[0124] The selected audio parameters include the gain values ​​of each stage, equalizer coefficients, parameters of the echo cancellation algorithm, parameters of the noise reduction algorithm, etc. These parameters are loaded into the corresponding audio processing modules and applied to the signal processing of hands-free calls in real time.

[0125] Through the above steps, the present invention achieves automatic detection of the reflective environment and adaptive adjustment of audio parameters, solving the problem that fixed parameters in the prior art cannot cope with environmental changes, and significantly improving the echo double-talk effect in reflective environments.

[0126] The method for optimizing echo dual-talk in reflective environments provided in this embodiment utilizes the mobile terminal's built-in motor and microphone. By analyzing the characteristics of the motor vibration signal, it determines whether the mobile terminal is in a reflective environment, requiring no additional hardware and achieving zero cost. Comprehensive analysis of amplitude and spectral characteristics accurately distinguishes between different usage states such as handheld, hard reflective surfaces, and soft reflective surfaces. It can actively detect at the start of a hands-free call and respond to environmental changes during the call, achieving full self-adaptation and ensuring that audio parameters match the current environment at all times. Through differentiated parameter adjustment strategies, the echo dual-talk effect in reflective environments reaches a level comparable to that in handheld scenarios, effectively solving the problems of trailing sounds and decreased dual-talk effect when placed on a table in existing technologies.

[0127] Example 2 This example provides a mobile terminal for implementing the method described in the above examples for optimizing echo double-talk effects in a reflective environment.

[0128] The mobile terminal includes a motor 5, a microphone 2, and a processor. Specifically, the motor 5 is used to generate mechanical vibration. The motor 5 can be a linear motor, a rotor motor, or other types of vibration motor. The motor 5 is connected to the processor via a control circuit, and the processor controls the vibration duration and intensity of the motor 5 by sending control signals (such as PWM signals).

[0129] Microphone 2 is used to acquire audio signals. Microphone 2 can be a MEMS microphone (microelectromechanical system microphone), an electret microphone, or other types of microphone. The output of microphone 2 is connected to the processor via an audio codec to convert the acquired analog audio signals into digital signals for processing by the processor.

[0130] The microphone 2 is typically installed at the bottom or side of the mobile terminal to pick up user voice and ambient sound. As shown in Figure 4, the microphone 2 is located at the bottom of the mobile terminal, close to the lower speaker 4. Because the microphone 2 is close to the lower speaker 4, it is easy to pick up a strong echo signal in hands-free mode, which is why the echo problem is more prominent in single-microphone mobile terminals.

[0131] The processor is used to execute audio processing and control logic. The processor can be a central processing unit (CPU), a digital signal processor (DSP), an application processor (AP), an audio processing chip, or a combination thereof. In a specific example, the processor is a system-on-a-chip (SoC) that integrates a CPU and a DSP, where the DSP is specifically responsible for real-time processing of audio signals, and the CPU is responsible for control logic and application program execution.

[0132] The processor is connected to components such as motor 5, microphone 2, memory, speaker, and acceleration sensor via a system bus or dedicated interface to achieve data exchange and control.

[0133] The processor's functions include: (1) controlling the motor vibration for a preset duration during hands-free calling: when the user initiates hands-free calling or movement is detected during hands-free calling, the processor sends a control signal to the drive circuit of the motor 5 to start the motor vibration and stops the motor vibration after a preset duration. The control signal can be a PWM (Pulse Width Modulation) signal, which controls the vibration intensity and duration by adjusting the duty cycle and frequency of the PWM.

[0134] (2) Acquire the vibration signal generated by the motor vibration collected by the microphone: The processor reads the digital audio data collected by the microphone 2 from the audio codec, which corresponds to the acoustic signal during the vibration of the motor 5. The digital audio data is stored in a buffer at a certain sampling rate, such as 16kHz or 48kHz, and sampling precision, such as 16-bit or 24-bit, for further analysis by the processor.

[0135] (3) Compare the collected vibration signal with the preset reflection environment feature signal: The processor executes the signal processing algorithm to extract features from the collected vibration signal, and then compares the extracted features with the preset reflection environment feature signal stored in the memory to calculate the difference or similarity and determine whether they match.

[0136] The preset reflection environment characteristic signals are stored in the non-volatile memory (such as Flash or EEPROM) of the mobile terminal and are written before the mobile terminal leaves the factory or through software updates. These characteristic data may include multiple sets of parameters corresponding to different reflection environment types, such as hard reflective surfaces and soft reflective surfaces.

[0137] (4) Select audio parameters based on comparison results: Based on the comparison results, the processor reads the corresponding audio parameter configuration from the memory, such as the first audio parameter, the second audio parameter or the default audio parameter, and loads these parameters into various modules of the audio processing flow, including the gain control module, the equalizer module, the echo cancellation module, the noise reduction module, etc.

[0138] The audio processing flow can be implemented in a DSP as a real-time signal processing method, or it can be implemented on a CPU through software algorithms, or it can be implemented using hardware accelerators, such as dedicated audio processing IP cores. These implementation methods are well-known technologies in the field.

[0139] In a preferred embodiment, the mobile terminal further includes an accelerometer. The accelerometer is used to detect changes in the mobile terminal's acceleration and spatial attitude. The accelerometer is typically a triaxial accelerometer, capable of measuring acceleration components in the X, Y, and Z directions respectively. The accelerometer is connected to the processor via I2C, SPI, or other interfaces, reporting acceleration data to the processor in real time.

[0140] The processor is also used to monitor movement via the accelerometer. The processor periodically reads data from the accelerometer, analyzes the trend of acceleration changes, and determines whether the mobile terminal is in motion.

[0141] When a movement that meets preset movement conditions is detected, the motor is controlled to vibrate for the preset duration after the movement ends. The processor determines whether the movement meets the preset conditions based on acceleration data, such as the movement duration exceeding a threshold, the acceleration change amplitude exceeding a threshold, or the attitude change exceeding a threshold. After the movement is detected to have ended, the motor vibration and environmental detection process is triggered, thereby achieving an adaptive response to environmental changes during the call.

[0142] When a user makes a hands-free call using the mobile terminal, the processor automatically executes the method described in the above embodiments to detect the reflection environment and adaptively adjust audio parameters, optimizing the echo two-way communication effect. The entire process requires no user intervention, and the mobile terminal can automatically optimize call quality according to the actual usage environment.

[0143] The mobile terminal can be an electronic device with hands-free calling function, such as a mobile phone, tablet computer, smart speaker, or vehicle terminal. The present invention does not limit the specific form of the mobile terminal.

[0144] Accordingly, other embodiments of this application may also provide a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the various method embodiments of this application. Computer-readable storage media include permanent and non-permanent, removable and non-removable media, and information storage can be implemented by any method or technology. Information may be computer-readable instructions, data structures, program modules, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transfer medium that can be used to store information accessible by a computing device.

[0145] In summary, this invention utilizes existing standard configurations of mobile terminals, such as motors, microphones, and accelerometers, achieving a zero-hardware-cost solution without adding any extra hardware components. This solution can be deployed in existing mobile terminal devices, has a wide range of applications, and low implementation costs. Furthermore, this invention automatically determines whether the mobile terminal is in a reflective environment and the type of reflective surface by analyzing the amplitude and spectral characteristics of the motor vibration signal. This invention not only actively detects the environment at the start of a hands-free call but also monitors movement during the call using an accelerometer. When a change in the mobile terminal's placement is detected, it automatically re-detects and adjusts parameters. This ensures that the mobile terminal maintains optimal echo two-way communication performance in various usage scenarios, such as handheld, placed on a table, or placed on a sofa.

[0146] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for optimizing echo double-talk in a reflective environment, characterized in that, include: During hands-free calling, control the motor to vibrate for a preset duration; Collect the vibration signal generated by the motor vibration; The collected vibration signal is compared with the preset reflection environment characteristic signal; audio parameters are selected based on the comparison result.

2. The method for optimizing echo double-talk in a reflective environment according to claim 1, characterized in that, The method of controlling the motor to vibrate for a preset duration during a hands-free call includes: controlling the motor to vibrate for the preset duration when the hands-free call begins; and / or controlling the motor to vibrate for the preset duration when movement is detected during the hands-free call.

3. The method for optimizing echo double-talk in a reflective environment according to claim 2, characterized in that, The process of controlling the motor to vibrate for the preset duration when a hands-free call begins includes: muting the hands-free downlink signal when the hands-free call begins; controlling the motor to vibrate for the preset duration during the downlink signal muting period; and restoring the hands-free downlink signal after the motor stops vibrating; and / or the process of controlling the motor to vibrate for the preset duration when movement is detected during a hands-free call includes: monitoring movement using an accelerometer; and controlling the motor to vibrate for the preset duration after the movement ends when movement that meets preset movement conditions is detected.

4. The method for optimizing echo double-talk in a reflective environment according to claim 1, characterized in that, The process of comparing the acquired vibration signal with a preset reflection environment feature signal includes: acquiring the signal features of the vibration signal, and comparing the signal features of the vibration signal with the signal features of the preset reflection environment feature signal; preferably, the signal features include amplitude features and / or spectral features, the amplitude features include the root mean square (RMS) value, and the spectral features include low-frequency band features and / or high-frequency band features; preferably, the process of comparing the signal features of the vibration signal with the signal features of the preset reflection environment feature signal includes: calculating the difference or similarity between the signal features of the vibration signal and the signal features of the preset reflection environment feature signal; when the difference is less than a preset difference threshold or the similarity is greater than a preset similarity threshold, it is determined that the vibration signal matches the preset reflection environment feature signal.

5. The method for optimizing echo double-talk in a reflective environment according to claim 4, characterized in that, The preset reflective environment characteristic signal includes a first reflective surface characteristic signal and a second reflective surface characteristic signal; preferably, the step of selecting audio parameters based on the comparison result includes: when the vibration signal matches the first reflective surface characteristic signal, selecting a first audio parameter optimized for the first reflective surface; when the vibration signal matches the second reflective surface characteristic signal, selecting a second audio parameter optimized for the second reflective surface; and when the vibration signal does not match either the first or second reflective surface characteristic signal, selecting a default audio parameter; preferably, the amplitude characteristic of the first reflective surface characteristic signal is higher than the amplitude characteristic of the second reflective surface characteristic signal; more preferably, the parameter adjustment amount of the first audio parameter optimized for the first reflective surface is greater than the parameter adjustment amount of the second audio parameter optimized for the second reflective surface.

6. The method for optimizing echo double-talk in a reflective environment according to claim 5, characterized in that, The first audio parameter optimized for the first reflective surface or the second audio parameter optimized for the second reflective surface shall be adjusted relative to the default audio parameter by at least one of the following: reducing the gain of the echo cancellation algorithm; increasing the gain of the noise reduction algorithm; and adjusting the equalizer parameters.

7. The method for optimizing echo double-talk in a reflective environment according to claim 6, characterized in that, The adjustment of equalizer parameters includes: performing low-frequency attenuation on the equalizer of the uplink signal; and performing low-frequency compensation on the equalizer of the downlink signal to compensate for the low-frequency attenuation of the uplink signal. Preferably, the reduction in gain of the echo cancellation algorithm is equal to the increase in gain of the noise reduction algorithm. More preferably, the reduction in gain of the echo cancellation algorithm is 3dB to 8dB, and the increase in gain of the noise reduction algorithm is 3dB to 8dB.

8. A mobile terminal, characterized in that, include: Motor; microphone; processor; wherein the processor is used to: control the vibration of the motor for a preset duration during hands-free calling; The system acquires the vibration signal generated by the motor vibration collected by the microphone; compares the acquired vibration signal with a preset reflection environment characteristic signal; and selects audio parameters based on the comparison result.

9. The mobile terminal according to claim 8, characterized in that, It also includes an acceleration sensor; the processor is used to monitor movement through the acceleration sensor, and when movement that meets preset movement conditions is detected, it controls the motor to vibrate for the preset duration after the movement ends.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the method for echo double talk in an optimized reflection environment as described in any one of claims 1 to 7.

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