Dual-microphone device for reducing CT voice noise

Abstract

The utility model discloses a double-microphone device for reducing CT voice noise. The double-microphone device comprises a main microphone, an auxiliary microphone, a noise reduction unit and a cable. The main microphone is arranged in a scanning cavity of the CT equipment, the auxiliary microphone is arranged at the top of the CT equipment, and the cable is connected with the main microphone, the auxiliary microphone and the noise reduction unit. The input end of the noise reduction unit is connected with the main microphone and the auxiliary microphone, and the output end is connected with external audio equipment such as a loudspeaker of a doctor operation room. The double-microphone equipment provided by the utility model adopts double microphones and a noise elimination technology, can provide clear voice information of a patient for a doctor in a noisy environment, is used for assisting the doctor in completing a CT scanning process, and has an echo elimination function.

Description

Technical Field

[0001] The utility model relates to a dual-microphone device for reducing CT voice noise, belonging to the technical field of medical equipment. Background Art

[0002] As a large-scale X-ray medical device, the safety and convenience of CT equipment operation are increasingly valued by manufacturers and doctors. X-rays prevent doctors and patients from communicating with each other at close range, and equipment noise affects the quality of voice communication between doctors and patients. Therefore, operating CT equipment remotely to communicate with patients has become a problem that needs to be solved.

[0003] In the Chinese utility model with patent number ZL 202322369543.8, a noise reduction device and its noise reduction array and CT rack are disclosed. The noise reduction device includes a shell and a shell cover matched with the shell. The shell is provided with a perforated plate resonance sound absorption structure, and a gap is formed between the shell cover base plate and a side plate of the shell, and the noise reduction effect of the noise reduction device is improved by the dual sound absorption effect of the narrow gap and the perforated plate.

[0004] In addition, in the Chinese utility model with patent number ZL 202121863104.7, a portable intelligent noise reduction device for voice communication is disclosed. The noise reduction device includes a main input and a reference input, the main input includes a useful signal and a noise signal, and the reference input is a noise signal. The reference input is superimposed with the signal in the main input, and the error signal generated after the superposition is the output signal of the system, which is used as the system output. The active noise reduction controller filters out the noise signal in the main input, realizes active noise reduction, restores the true state of the useful signal, and realizes the voice enhancement and active noise reduction functions in the high noise environment of the construction site.

[0005] Similarly, the existing technologies all obtain the de-noised speech signal in a steady-state noise environment by reducing the noise of the device itself or using the principle of superposition of noise signal and useful signal. Practice has proved that the above technical measures do not have the echo cancellation function and do not have the noise reduction function in a non-steady-state noise environment. Summary of the invention

[0006] The technical problem to be solved by the utility model is to provide a dual-microphone device for reducing CT voice noise.

[0007] In order to achieve the above technical objectives, the utility model adopts the following technical solutions:

[0008] According to an embodiment of the utility model, a dual-microphone device for reducing CT voice noise is provided, comprising a main microphone, a secondary microphone, a noise reduction unit and a cable; wherein,

[0009] The noise reduction unit includes an analog signal to digital signal converter, a digital signal processor, a microcontroller unit, a digital signal to analog signal converter and a programmable gain amplifier; wherein the input end of the noise reduction unit is connected to the analog signal to digital signal converter, and the analog signal to digital signal converter is connected to the input end of the digital signal processor; the control end of the digital signal processor is connected to the microcontroller unit, and the output end of the digital signal processor is connected to the digital signal to analog signal converter; the output end of the digital signal to analog signal converter is connected to the programmable gain amplifier, and the output end of the programmable gain amplifier is connected to the output end of the noise reduction unit; the output end of the noise reduction unit is connected to an external audio device for audio output

[0010] The main microphone is arranged in the scanning cavity of the CT device and connected to the cable, and the other end of the cable is connected to the input end of the noise reduction unit;

[0011] The auxiliary microphone is arranged on the top of the CT device and connected to the cable, and the other end of the cable is connected to the input end of the noise reduction unit.

[0012] Preferably, the main microphone is arranged in the upper half of the scanning cavity, biased to one side in the vertical direction, with the sound receiving direction facing the patient, so as to pick up the patient's voice and noise.

[0013] Preferably, the secondary microphone is disposed at a fan port of the CT device to pick up noise and patient voice.

[0014] Preferably, the cable is a shielded cable, and the shielding layer is grounded.

[0015] Preferably, the main microphone and the auxiliary microphone are condenser electret microphones.

[0016] Preferably, the main microphone is disposed in an acoustic focusing area of ​​the scanning cavity.

[0017] Preferably, the output end branch of the programmable gain amplifier connects the analog signal to a digital signal converter to achieve an echo cancellation function.

[0018] Preferably, the dual microphone device further includes a speaker; wherein,

[0019] The speaker is arranged in the upper half of the scanning cavity, biased to one side in the vertical direction and facing the patient, and is used for playing audio instructions.

[0020] Preferably, the loudspeaker and the main microphone are arranged symmetrically with respect to the vertical direction.

[0021] Compared with the prior art, the utility model adopts dual microphones and noise elimination technology, which can provide doctors with clear voice information of patients in noisy environments, so as to assist doctors in completing the CT scanning process, and has an echo elimination function. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic structural diagram of a dual-microphone device for reducing CT voice noise in the first embodiment of the utility model;

[0023] Figure 2 for Figure 1 A rear view of a dual microphone device in FIG.

[0024] Figure 3 for Figure 1 Electrical schematic of the dual-microphone setup in . DETAILED DESCRIPTION

[0025] The technical content of the present utility model is described in detail below with reference to the accompanying drawings and specific embodiments.

[0026] The technical concept in the embodiment of the utility model is to set multiple microphones (also called microphones) on the CT device, reduce steady-state noise based on the working principle of MMSE-LSA, and reduce non-steady-state noise with a dual microphone array. Specifically, a secondary microphone is set in the area with the highest noise of the CT device (such as the area of ​​the cooling fan), and a main microphone is set in the area of ​​the CT device close to the patient (such as the scanning ring). The difference in sound picked up by the two microphones is analyzed and calculated in the program to remove the noise picked up by the secondary microphone and retain the sound of the main microphone. In other words, the noise is removed from the noisy speech signal to obtain a pure speech signal.

[0027] First embodiment

[0028] like Figure 1 and Figure 2 As shown, a dual-microphone device for reducing CT voice noise provided by an embodiment of the utility model includes a main microphone 1, a secondary microphone 2, a noise reduction unit 3 (not shown in the figure) and a cable 5. The CT device provided by the prior art includes a front panel 10, a scanning cavity 20 and a plurality of fan ports 30. The embodiment of the utility model takes the fan port 30 as an example of the area with the largest noise of the CT device, and takes the scanning cavity 20 as an example of the area close to the patient.

[0029] The main microphone 1 is arranged in the upper half of the scanning cavity 20, deviating to one side (to the left or right) in the vertical direction and facing the patient, for picking up the patient's voice and noise at the same time. In engineering practice, the transition zone 40 of the scanning cavity 20 is the middle area connecting the front panel 10 and the scanning cavity 20, and is in the shape of a hyperbolic body with a gradually changing diameter. It can be regarded as an acoustic sound wave collector and has the characteristics of acoustic focusing. The main microphone 1 is arranged in the acoustic focusing area of ​​the transition zone 40.

[0030] The auxiliary microphone 2 is disposed on the top of the front panel 10 , close to the fan port 30 , for picking up noise and the patient's voice at the same time.

[0031] The cable 5 connects the main microphone 1, the auxiliary microphone 2 and the noise reduction unit 3, and adopts a shielded cable with a grounded shielding layer to avoid interference from the radiation of the CT device. The cable is routed along the inner side of the housing of the CT device, such as the back of the front panel.

[0032] Due to the performance characteristics of the CT device, the decibel value of the patient's voice picked up by the main microphone 1 is greater than the decibel value of the noise picked up, and the decibel value of the noise picked up by the auxiliary microphone 2 is greater than the decibel value of the patient's voice picked up.

[0033] like Figure 3 As shown, the main microphone 1 and the auxiliary microphone 2 are connected to the input end of the noise reduction unit 3. The noise reduction unit 3 includes an ADC (analog-to-digital converter), a DSP (digital signal processor), an MCU (microcontroller), a DAC (digital-to-analog converter) and a PGA (programmable gain amplifier). Among them, the ADC at the input end of the noise reduction unit 3 is connected to the input end of the DSP, the control end of the DSP is connected to the MCU, the output end of the DSP is connected to the DAC, the output end of the DAC is connected to the PGA, and the output end of the PGA is connected to an external audio device for audio output. The DSP is provided with an MMSE-LSA algorithm program for steady-state noise processing and a comparison algorithm program for non-steady-state noise processing.

[0034] The main microphone 1 and the auxiliary microphone 2 are respectively connected to the ADC of the input end of the noise reduction unit 3, and the output end of the noise reduction unit 3 is connected to the speaker in the doctor's operating room.

[0035] In engineering practice, the noise reduction unit 3 uses a 32-bit DSP processing chip, which can achieve a noise elimination capability of 40 dB. The noise elimination capability is related to the processing capability of the processing chip used.

[0036] 1. Noise reduction method for steady-state noise

[0037] The noise reduction unit 3 performs noise reduction according to the working principle of MMSE-LSA. The working principle is described in the paper "Speech Enhancement Using a Minimum Mean-Square Error Short-Time Spectral Amplitude Estimate" (published in "IEEE Transactions on Acoustics, Speech, and Signal Processing" Vol. 32 No. 6, published in December 1984). As a prior art, it will not be described in detail here.

[0038] When the noise is a steady-state signal, the noise variance can be continuously updated by detecting non-speech segments using VAD (Voice Activity Detection). It is worth noting that the non-speech segments (i.e., noise signals) are obtained through the VAD function, while the non-speech segments can be considered as pure noise segments. Thus, useful information can be extracted from the pure noise signal, such as obtaining the noise spectrum by Fourier transform, and then further processed.

[0039] The noise reduction unit 3 uses the above method to reduce the steady-state noise picked up by the main microphone 1 and the auxiliary microphone 2. Sounds with stable frequencies and all sounds picked up by the auxiliary microphone 2 can be eliminated by noise reduction as long as the amplitude is close to the sound picked up by the main microphone 1.

[0040] 2. Noise reduction method for non-steady-state noise

[0041] The main microphone 1 and the auxiliary microphone 2 pick up the patient's voice at the same time. If the signal amplitude of the main microphone 1 is greater than a certain sound pressure level (5-7dB in engineering practice) of the auxiliary microphone 2 and there is no fixed frequency sound, it is judged to be the patient's voice close to the main microphone 1, and the sound signal is used as the output audio. If the difference between the signal amplitudes of the main microphone 1 and the auxiliary microphone 2 is less than a certain sound pressure level (5-7dB in engineering practice), it is judged as noise and noise reduction is performed.

[0042] The sound picked up by the main microphone 1 and the auxiliary microphone 2 is converted by the ADC of the noise reduction unit 3, and then enters the DSP for steady-state and non-steady-state noise algorithm comparison processing to retain useful signals. After DAC conversion, it is output after audio gain PGA preprocessing. At this time, the sound signal is connected to the external speaker for sound.

[0043] Second embodiment

[0044] Different from the above embodiment, the audio signal outputted from the PGA output terminal of the noise reduction unit 3 leads to a branch and returns to the ADC of the noise reduction unit 3 for processing, thereby realizing the acoustic echo cancellation (AEC) function.

[0045] When the sound insulation between the operating room and the scanner is poor, the sound from the speaker in the doctor's operating room is transmitted to the microphone of the CT device through the air, forming an echo, which may cause a howling phenomenon. The noise reduction unit 3 provided in this embodiment is provided with an echo cancellation function, which can eliminate the echo.

[0046] Third embodiment

[0047] Different from the above embodiment, the above dual-microphone device includes a microphone array composed of multiple main microphones 1 and auxiliary microphones 2, which can calculate the direction of the speaker relative to the CT device. Among them, the noise reduction unit 3 calculates the direction of the sound source using TDOA (Time Difference Of Arrival) technology according to the installation position of the microphone array and the arrival time difference of the sound picked up by each microphone.

[0048] Fourth embodiment

[0049] Different from the above embodiment, the above dual microphone device further includes a speaker 4, which is connected via a cable. The speaker 4 is arranged in the upper half of the scanning cavity 20, biased to one side in the vertical direction and facing the patient, and is used to play the instructions of the doctor in the operating room to the patient. The speaker 4 and the main microphone 1 are arranged symmetrically relative to the vertical direction.

[0050] When the sound insulation between the operating room and the scanner is poor, the sound from the speaker 4 is transmitted through the air to the microphone in the doctor's operating room, forming an echo, which may cause a howling phenomenon. Or the sound from the speaker 4 is picked up by the main microphone 1 and the auxiliary microphone 2 and transmitted back to the speaker in the doctor's operating room, which will also form an echo. The echo cancellation function set in the noise reduction unit 3 can eliminate the echo.

[0051] To prevent doctors from being exposed to excessive X-rays, the scanning room of the CT equipment and the doctor's operating room are isolated from each other. Doctors and patients communicate with each other through microphones and speakers. The noise in the scanning room affects the quality of voice communication between doctors and patients.

[0052] Noise can be divided into two types: ① Steady-state noise, which is noise with a fixed frequency or that is emitted regularly and steadily, such as motors, fans, mechanical equipment, and low-frequency background sounds in the environment; ② Non-steady-state noise, which is sudden, random sounds with irregular frequencies, such as clapping, footsteps, crying children, people chatting, and cars passing by. The environmental noise in a CT scanning room is close to steady-state noise.

[0053] The secondary microphone 2 is set in the area with the highest noise of the CT equipment, such as the area near the cooling fan of the equipment. The secondary microphone 2 picks up the patient's voice and noise at the same time. Due to the performance characteristics of the CT equipment, the decibel value of the noise picked up is greater than the decibel value of the patient's voice picked up.

[0054] The main microphone 1 is set in the area close to the patient of the CT device, such as the inner ring area of ​​the scanning ring. The main microphone 1 picks up the patient's voice and noise at the same time. Due to the performance characteristics of the CT device, the decibel value of the patient's voice picked up is greater than the decibel value of the noise picked up.

[0055] The input end of the noise reduction unit 3 is connected to the main microphone 1 and the auxiliary microphone 2, and the output end is connected to the speaker in the doctor's operating room. The noise reduction unit 3 filters out the steady-state noise and non-steady-state noise in the patient's voice through the MMSE-LSA algorithm program and the comparison algorithm program. The noise-reduced patient voice is sent out through the speaker in the doctor's operating room.

[0056] For steady-state noise, the embodiment of the utility model analyzes and calculates the sound frequency picked up by the main microphone 1 and the auxiliary microphone 2 through the noise reduction unit 3. When a certain frequency appears stably and continuously, it is determined that this sound frequency is a noise frequency. At the same time, the noise frequency is attenuated and suppressed to reduce the output. The human voice speaking in the noise background has an irregular frequency, and this part of the sound is boosted and maintained for output.

[0057] For non-steady-state noise, the embodiment of the utility model uses a dual-microphone method, with the main microphone 1 facing the patient to be picked up and the auxiliary microphone 2 facing the noise source. When the noise reduction unit 3 determines that the difference in the sound picked up by the two microphones exceeds a certain sound pressure level (5-7dB in engineering practice), the sound difference is used to perform analysis and calculation within the program to remove the noise picked up by the auxiliary microphone 2 and retain the sound of the main microphone 1. For example, the patient's voice picked up by the main microphone 1 is 70dB, and the patient's voice picked up by the auxiliary microphone 2 is less than 60dB. The patient's voice is retained and other surrounding noises are eliminated.

[0058] In summary, the dual-microphone device for reducing CT voice noise provided by the embodiment of the utility model picks up the patient's voice through the main microphone, picks up the CT equipment noise through the secondary microphone, and the noise reduction unit performs noise reduction processing to filter out the noise and provide clear voice. In a noisy environment, the doctor is provided with clear voice information of the patient and is assisted in completing the CT scanning process.

[0059] It should be noted that the above-mentioned multiple embodiments are only examples, and the technical solutions of the various embodiments can be combined, all of which are within the protection scope of the present utility model.

[0060] The orientation or position relationship indicated by the terms "upper", "lower", "top", "bottom", etc. is based on the orientation or position relationship shown in the drawings and is only for the convenience of describing the present invention and simplifying the description. It does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be understood as a limitation on the present invention.

[0061] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present utility model, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0062] The above is a detailed description of the dual-microphone device for reducing CT voice noise provided by the utility model. For those skilled in the art, any obvious changes made to the utility model without departing from the essence of the utility model will constitute an infringement of the patent right of the utility model and will bear corresponding legal liabilities.

Claims

1. A dual microphone device for reducing CT speech noise, characterized in that It includes a main microphone, a secondary microphone, a noise reduction unit and a cable; among which, The noise reduction unit is arranged in the CT device, and includes an analog signal to digital signal converter, a digital signal processor, a microcontroller unit, a digital signal to analog signal converter and a programmable gain amplifier; wherein the input end of the noise reduction unit is connected to the analog signal to digital signal converter, and the analog signal to digital signal converter is connected to the input end of the digital signal processor; the control end of the digital signal processor is connected to the microcontroller unit, and the output end of the digital signal processor is connected to the digital signal to analog signal converter; the output end of the digital signal to analog signal converter is connected to the programmable gain amplifier, and the output end of the programmable gain amplifier is connected to the output end of the noise reduction unit; the output end of the noise reduction unit is connected to an external audio device for audio output; The main microphone is arranged in the scanning cavity of the CT device and connected to the cable, and the other end of the cable is connected to the input end of the noise reduction unit; The auxiliary microphone is arranged on the top of the CT device and connected to the cable, and the other end of the cable is connected to the input end of the noise reduction unit.

2. The dual microphone device according to claim 1, characterized in that: The main microphone is arranged in the upper half of the scanning cavity, biased to one side in the vertical direction, with the sound receiving direction facing the patient, for picking up the patient's voice and noise.

3. The dual microphone device according to claim 2, characterized in that: The auxiliary microphone is arranged at the fan port of the CT device to pick up noise and patient voice.

4. The dual microphone device according to claim 3, characterized in that: The cable is a shielded cable, and the shielding layer is grounded.

5. The dual microphone device according to claim 4, characterized in that: The main microphone and the auxiliary microphone are condenser electret microphones.

6. The dual microphone device according to claim 5, characterized in that: The main microphone is arranged in the acoustic focusing area of ​​the scanning cavity.

7. The dual microphone device according to claim 1, characterized in that: The output end branch of the programmable gain amplifier connects the analog signal to a digital signal converter to achieve an echo cancellation function.

8. The dual microphone device as claimed in claim 1, characterized in that Also included is a speaker; wherein, The speaker is arranged in the upper half of the scanning cavity, biased to one side in the vertical direction and facing the patient, and is used for playing audio instructions.

9. The dual microphone device according to claim 8, characterized in that: The loudspeaker and the main microphone are arranged symmetrically with respect to the vertical direction.

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