WO2023239326A1 - Auscultation system and technique with noise reduction technique - Google Patents

Auscultation system and technique with noise reduction technique Download PDF

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Publication number
WO2023239326A1
WO2023239326A1 PCT/TR2023/050506 TR2023050506W WO2023239326A1 WO 2023239326 A1 WO2023239326 A1 WO 2023239326A1 TR 2023050506 W TR2023050506 W TR 2023050506W WO 2023239326 A1 WO2023239326 A1 WO 2023239326A1
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WO
WIPO (PCT)
Prior art keywords
noise
main microphone
microphones
processor unit
microphone
Prior art date
Application number
PCT/TR2023/050506
Other languages
French (fr)
Inventor
Onur Yusuf CINAR
Kemal Ozanoglu
Zeynep Yasemin Kahya
Original Assignee
Bogazici Universitesi
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from TR2022/009553 external-priority patent/TR2022009553A2/en
Application filed by Bogazici Universitesi filed Critical Bogazici Universitesi
Publication of WO2023239326A1 publication Critical patent/WO2023239326A1/en

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Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B7/00—Instruments for auscultation
    • A61B7/02—Stethoscopes
    • A61B7/04—Electric stethoscopes
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R1/00—Details of transducers, loudspeakers or microphones
    • H04R1/46—Special adaptations for use as contact microphones, e.g. on musical instrument, on stethoscope
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10L—SPEECH ANALYSIS TECHNIQUES OR SPEECH SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING TECHNIQUES; SPEECH OR AUDIO CODING OR DECODING
    • G10L21/00—Speech or voice signal processing techniques to produce another audible or non-audible signal, e.g. visual or tactile, in order to modify its quality or its intelligibility
    • G10L21/02—Speech enhancement, e.g. noise reduction or echo cancellation
    • G10L21/0208—Noise filtering
    • G10L21/0216—Noise filtering characterised by the method used for estimating noise
    • G10L2021/02161—Number of inputs available containing the signal or the noise to be suppressed
    • G10L2021/02165—Two microphones, one receiving mainly the noise signal and the other one mainly the speech signal
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10L—SPEECH ANALYSIS TECHNIQUES OR SPEECH SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING TECHNIQUES; SPEECH OR AUDIO CODING OR DECODING
    • G10L21/00—Speech or voice signal processing techniques to produce another audible or non-audible signal, e.g. visual or tactile, in order to modify its quality or its intelligibility
    • G10L21/02—Speech enhancement, e.g. noise reduction or echo cancellation
    • G10L21/0208—Noise filtering
    • G10L21/0216—Noise filtering characterised by the method used for estimating noise
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R3/00—Circuits for transducers, loudspeakers or microphones
    • H04R3/005—Circuits for transducers, loudspeakers or microphones for combining the signals of two or more microphones

Definitions

  • the present invention relates to an auscultation system comprising a digital stethoscope for detecting sounds within a body.
  • the invention relates in detail to an auscultation system comprising a digital stethoscope with noise-reduction capability.
  • Auscultation is performed to listen to the sounds produced by the body.
  • the auscultation process allows the sounds formed in a person's body to be heard through a stethoscope.
  • Digital stethoscopes transform analog sound waves formed within the body into digital sound waves by detecting them through a microphone.
  • Digital stethoscopes include amplifiers to make the sound wave received through the microphone more distinguishable. In this way, low-power sound waves formed in the body are also detected through the microphone.
  • Digital stethoscopes also ensure that the sounds that occur inside the body can be recorded and/or transferred to a remote terminal.
  • Digital stethoscopes strengthen the sound waves received by the microphone and also cause the noise signals received by the microphone to be strengthened.
  • Noise signals may be erroneous signals received by the microphone or external sounds from the environment. These noise signals need to be separated from the sounds inside the body, which is the main target. For this reason, there are studies in the art to remove the noise signal in digital stethoscopes.
  • the noise-extracting studies known in the present art are performed by filtering the audio signal received by the microphone. Said filtering can be done according to signal strength and signal frequency.
  • the sound waves that occur inside the body usually have low frequencies. For this reason, the sound signals in this frequency range can be filtered by performing frequency analysis of the sound waves formed in the body. Noise extraction in this way cannot give high performance when ambient noise is in the range close to the body sound frequency.
  • the digital stethoscope may include an acoustic chamber for collecting sound waves in a target area. In this case, the power of the sound waves in the target area is increased by positioning the microphone in the acoustic chamber. In this case, it is ensured that the sound formed in the body is filtered by defining and removing the low-power audio signals as noise. However, this causes the low-power sound waves in the body to be ignored in the noise-generation process.
  • the present invention relates to an auscultation system for eliminating the above-mentioned disadvantages and bringing new advantages to the related technical field.
  • An object of the invention is to provide an auscultation system to provide listening with increased accuracy.
  • Another object of the invention is to provide a digital stethoscope to distinguish the sounds to be detected from the noises.
  • the present invention relates to a digital stethoscope for detecting sounds within the body, comprising an acoustic chamber for collecting sound waves occurring in a target area, a main microphone for detecting the sound in said acoustic chamber and a processor unit for processing the sound signal received by the said main microphone. Accordingly, it is characterized in that it comprises at least three noise microphones for detecting noise from outside the target zone, said noise microphones being positioned at a predetermined angle between them around an axis where the main microphone is the origin point, said processor unit being configured to perform the following process steps:
  • a possible embodiment of the invention is characterized in that said noise microphones are positioned at an equal angle between them around a circular axis in which the main microphone is the origin point. In this way, the accuracy of the noise pattern determined by the processor unit is increased. Thus, it is ensured that the voices formed in the target area are listened to with increased accuracy.
  • Another possible embodiment of the invention is characterized in that the distances between said noise microphones and the main microphone are equal. In this way, the accuracy of the actual noise pattern determined by the processor unit is increased. Thus, it is ensured that the voices formed in the target area are listened to with increased accuracy.
  • Another possible embodiment of the invention is characterized in that the processor unit is configured to detect a noise pattern of the noise signal it receives from the noise microphone.
  • Another possible embodiment of the invention is characterized in that the processor unit is configured to detect said noise pattern in the audio signal received from the main microphone.
  • Another possible embodiment of the invention is characterized in that the processor unit is configured to perform the process of removing said noise pattern from the audio signal.
  • Another possible embodiment of the invention is characterized in that the processor unit is configured to detect the noise signals received from the noise microphones using said noise pattern using a peak detection algorithm.
  • Another possible embodiment of the invention is characterized in that the main microphone is closer to the target area than the noise microphones. Thus, it is ensured that the main microphone perceives the sounds generated in the target area as more powerful than the noise microphones.
  • Another possible embodiment of the invention is characterized in that the main microphone is positioned at a focal point of the acoustic chamber.
  • the main microphone is enabled to detect the sound waves in the target area in an amplified manner.
  • Another possible embodiment of the invention is characterized in that it is associated with a memory unit for recording the signals received by the processor unit.
  • the main microphone is a directional microphone.
  • the main microphone can be directed to the target area. In this way, it is ensured that the main microphone perceives the sound waves in the target area in an amplified manner.
  • the present invention is also a digital stethoscope as described above, which relates to a method for filtering noise signals sensed by the main microphone. Accordingly, it is characterized in that the processor unit is configured to perform the following steps: a) simultaneously recording the sound signal received from the main microphone and the noise signals received from the noise microphones, b) determining a noise pattern if it detects a signal pattern match between the noise signals at a predetermined rate by comparing the noise signals it receives from the noise microphones, c) detecting a phase shift of the said noise pattern within the noise signals, d) determining an actual noise signal within the sound signal received from the main microphone by calculating the phase shifts detected within the noise signals of the noise pattern according to the predetermined distances between the noise microphones, e) removing the actual noise signal from the audio signal.
  • Another possible embodiment of the invention is characterized in that the processor unit is configured to use a peak detection algorithm in operation step "b". Thus, it is ensured that the processor unit determines the noise pattern with increased accuracy.
  • Another possible embodiment of the invention is characterized in that the processor unit is configured to use a triangulation algorithm in the processing step "d". Thus, it is ensured that the processor unit determines the actual noise pattern with increased accuracy.
  • Another possible embodiment of the invention is characterized in that the processor unit is configured to calibrate the audio signal with a calibration constant after the operation step "e". Thus, the accuracy of the sounds generated in the target area of the processor unit is increased.
  • Figure 1a shows a representative frontal view of the digital stethoscope.
  • Figure 1b shows a representative side view of the digital stethoscope.
  • Figure 2 shows a representative view of the configuration of the digital stethoscope.
  • Figure 3 shows a representative view of the auscultation system.
  • the invention relates to an auscultation system (10) for listening to sounds within a body.
  • the auscultation system (10) provides instant listening or recording of the sounds in a target area to be listened to later or to be listened to remotely in telemedicine (remote health) applications.
  • the auscultation system (10) of the invention includes a digital stethoscope (100) for detecting sounds within a body.
  • Said digital stethoscope (100) comprises an acoustic chamber (110) for collecting the sounds generated in a target area.
  • Said acoustic chamber (110) has an acoustic structure to collect the sound waves formed in the target area in which it is directed.
  • the digital stethoscope (100) includes a main microphone (120) for detecting sound within the acoustic chamber (110).
  • the main microphone (120) generates an audio signal by sensing sound waves collected within the acoustic chamber (110).
  • the main microphone (120) is positioned at a focal point of the acoustic chamber (110).
  • the main microphone (120) is a directional microphone. In this way, the main microphone (120), which is directed to the target area, perceives the sounds generated in the target area in an amplified manner.
  • the digital stethoscope (100) also includes a processor unit (140) for processing the audio signal generated by the main microphone (120). The main microphone (120) sends the audio signal it generates to the processor unit (140).
  • the digital stethoscope (100) of the invention comprises at least three noise microphones (130) for detecting noise from outside the target zone.
  • the noise microphones (130) are positioned such that there is a predetermined angle between them around an axis where the main microphone (120) is the point of origin.
  • the noise microphones (130) generate a noise signal according to the noise they detect and send said noise signal to the processor unit (140).
  • the object of the digital stethoscope (100) is to determine an actual noise signal based on the noise signals received by the processor unit (140) from the noise microphones (130) and to extract said actual noise signal from the audio signal received from the main microphone (120). Thus, it is ensured that the sound waves formed in the target area are listened to with increased accuracy.
  • the processor unit simultaneously records the audio signal received from the main microphone (120) and the noise signals received from the noise microphones (130).
  • the processor unit (140) detects a predetermined ratio of signal pattern matching between the noise signals by comparing the noise signals it receives from the noise microphones (130).
  • the positioning of the noise microphones (130) in such a way that there is a predetermined angle between them around an axis where the main microphone (120) is the point of origin creates a phase difference between the sound waves they perceive. For this reason, the noise signals produced by the noise microphones (130) have similar patterns and different phase angles.
  • the processor unit (140) thus detects a predetermined matching of the signal pattern between the noise signals.
  • the processor unit (140) determines a noise pattern according to the signal pattern matching.
  • the processor unit (140) detects a phase shift of said noise pattern within the noise signals. That is, it detects the phase shift of the determined noise pattern within the noise signal produced by each noise microphone (130). In this way, the processor unit (140) detects by which noise microphone (130) the noise comes. Since the distance between the noise microphones (130) and the main microphone (120) is predetermined, the processor unit (140) determines an actual noise signal within the audio signal received from the main microphone (120). The processor unit (140) extracts the actual determined noise signal from the audio signal. Thus, it is ensured that the sound waves formed in the target area are separated from the noise sounds such as the external environment. Thus, it is ensured that the sound waves formed in the target area are listened to with increased accuracy.
  • the processor unit (140) is configured to perform the following steps, respectively: a) simultaneously recording the sound signal received from the main microphone (120) and the noise signals received from the noise microphones (130) b) determining a noise pattern if it detects a signal pattern match between the noise signals at a predetermined rate by comparing the noise signals it receives from the noise microphones (130) c) detecting a phase shift of the said noise pattern within the noise signals, d) determining an actual noise signal within the sound signal received from the main microphone (120) by calculating the phase shifts detected within the noise signals of the noise pattern according to the predetermined distances between the noise microphones (130) e) removing the actual noise signal from the audio signal.
  • the processor unit (140) uses a peak detection algorithm in operation step "b".
  • Said peak determination algorithm is a pattern-matching algorithm in the state of the art.
  • the peak detection algorithm detects a match between the noise signals by determining the maximum points of the noise signals.
  • the processor unit (140) uses a triangulation algorithm in the "d" operation step.
  • the aforementioned triangulation algorithm was created according to the mathematical method known as "triangulation” in the art.
  • the processor unit (140) calculates the phase shifts detected within the noise signals of the noise pattern according to the predetermined distances between the noise microphones (130) and determines an actual noise signal within the audio signal received from the main microphone (120).
  • the processor unit (140) calibrates the audio signal with a calibration constant after the "e” operation step. In this way, the audio signal is calibrated after the noises are separated from the audio signal received from the main microphone (120).
  • the noise microphones (130) are positioned at an equal angle between them around a circular axis where the main microphone (120) is the point of origin. In this embodiment, the distances between the noise microphones (130) and the main microphone (120) are equal. Likewise, the noise microphones (130) are positioned at an angle of 120 degrees between them around a circular axis where the main microphone (120) is the point of origin. In a possible embodiment of the invention, the noise microphones (130) are positioned within the acoustic chamber (110) and at different points from the focal point of the acoustic chamber (110). In another embodiment, the acoustic noise microphones (130) are positioned outside or around the acoustic chamber (110).
  • the auscultation system (10) comprises a memory unit (150) associated with the processor unit (140) in a possible embodiment of the invention.
  • the memory unit (150) allows the processor unit (140) to record the received signals.
  • the processor unit (140) has a machine-learning algorithm trained with the signals stored in the memory unit (150). Said machine learning algorithm increases the accuracy of the peak detection algorithm, triangulation algorithm, and calibration constant. In this way, the accuracy of the detection of the sounds formed in the target area is increased by the digital stethoscope (100).
  • the auscultation system (10) comprises a communication unit (160) associated with the processor unit (140) in a possible embodiment of the invention.
  • Said communication unit (160) enables the digital stethoscope (100) to be connected to a communication network (170) and said communication network (170) enables the listening of the sounds detected by the digital stethoscope (100) by a mobile terminal (180).
  • the communication unit (160) may be a Wi-Fi module known in the art.
  • the communication network (170) is preferably a network such as the Internet.
  • the mobile terminal (180) may be a device such as a tablet, phone, or computer connected to the communication network (170).
  • a healthcare professional can connect to the communication network (170) via the mobile terminal (180) and listen to the sounds detected by the digital stethoscope (100) connected to the communication network (170) in a remote location.
  • the digital stethoscope (100) can record the detected sounds in a database. In this way, auscultation is performed remotely on sick people. In addition, auscultation data are recorded.
  • the digital stethoscope (100) may comprise amplifiers associated with the main microphone (120) and the noise microphones (130) in a possible embodiment of the invention. Said amplifiers amplify the sound waves perceived by the microphones as known in the art.
  • the digital stethoscope (100) may include transducers associated with the main microphone (120) and the noise microphones (130). Said transducers convert the sound waves perceived by the microphones from the analog signal to the digital signal as known in the art.
  • the digital stethoscope (100) may include filters associated with the main microphone (120) and the noise microphones (130). Said filters filter certain frequency ranges of the sound waves perceived by the microphones as known in the art.
  • a first noise source (201) emits a noise.
  • the target area to be listened to is out of the page.
  • the main microphone (120) positioned at the focal point of the acoustic chamber (110) generates an audio signal by sensing the sounds generated in the target area and the noise from the first noise source (201).
  • the main microphone (120) detects the sounds generated in the target area more strongly than the noise from the first noise source (201).
  • the noise microphones (130) also detect sounds from the target area and noise from the first noise source (201 ). Accordingly, it generates a noise signal.
  • the noise microphones (130) are positioned outside the acoustic chamber (110) or at a point different from the focal point, they detect the sounds coming from the target area at a negligible level. In this way, the noise microphones (130) only detect noise from the first noise source (201 ).
  • the processor unit (140) simultaneously records the audio signal received from the main microphone (120) and the noise signals received from the noise microphones (130) to the memory unit (150). It then compares the noise signals using the peak detection algorithm and determines a noise pattern. It then detects the phase difference of the determined noise pattern with the noise signals.
  • the phase difference here is due to the distance x+x between the second noise microphone (132) and the third noise microphone (133); the distance x between the second noise microphone (132) and the first noise microphone (131 ); the distance x between the first noise microphone (131 ) and the third noise microphone (133).
  • the processor unit (140) detects that the first noise source (201) is located on the second noise microphone (132) side. Accordingly, since the distance between the noise microphones (130) and the main microphone (120) is defined in the processor unit (140), the processor unit (140) determines an actual noise pattern in the audio signal received from the main microphone (120). It then extracts the actual noise pattern from the audio signal. The actual noise pattern then calibrates the output audio signal with a calibration constant. Thus, it is ensured that the sounds formed in the target area are separated from the unwanted noises.
  • a second noise source (202) emits a noise.
  • the target area to be listened to is outside of the page.
  • the main microphone (120) positioned at the focal point of the acoustic chamber (110) generates an audio signal by sensing the sounds generated in the target area and the noise from the second noise source (202).
  • the main microphone (120) detects the sounds generated in the target area more strongly than the noise from the first noise source (201).
  • the noise microphones (130) also detect sounds from the target area and noise from the second noise source (202). Accordingly, it generates a noise signal.
  • the noise microphones (130) are positioned outside the acoustic chamber (110) or at a point different from the focal point, they detect the sounds coming from the target area at a negligible level. In this way, the noise microphones (130) only detect noise from the second noise source (202).
  • the processor unit (140) simultaneously records the audio signal received from the main microphone (120) and the noise signals received from the noise microphones (130) to the memory unit (150). It then compares the noise signals using the peak detection algorithm and determines a noise pattern. It then detects the phase difference of the determined noise pattern with the noise signals.
  • the phase difference here is due to the z+y distance between the first noise microphone (131) and the second noise microphone (132); the z+y distance between the first noise microphone (131 ) and the third noise microphone (133). Since there is no vertical distance difference between the second noise microphone (132) and the second noise source (202) of the third noise microphone (133), there is no phase difference between the noise signals generated by the second noise microphone (132) and the third noise microphone (133). In this way, the processor unit (140) detects that the second noise source (202) is located on the side of the first noise microphone (131 ).
  • the processor unit (140) determines an actual noise pattern in the audio signal received from the main microphone (120). It then extracts the actual noise pattern from the audio signal. The actual noise pattern then calibrates the output audio signal with a calibration constant. Thus, it is ensured that the sounds formed in the target area are separated from the unwanted noises.

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  • Acoustics & Sound (AREA)
  • Engineering & Computer Science (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
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  • Heart & Thoracic Surgery (AREA)
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Abstract

The invention relates to a digital stethoscope (100) for detecting sounds within the body comprising an acoustic chamber (110) for collecting sound waves occurring in a target area, a main microphone (120) for detecting sound within the said acoustic chamber (110), and a processor unit (140) for processing the sound signal received by said main microphone (120). Accordingly, the invention is characterized in that it comprises at least three noise microphones (130) for sensing noise from outside the target area, said noise microphones (130) being positioned at a predetermined angle between them around an axis where the main microphone (120) is the origin point, said processor unit (140) being configured to perform the steps of simultaneously recording the sound signal received from the main microphone (120) and the noise signals received from the noise microphones (130), determining a noise pattern if it detects a signal pattern match between the noise signals at a predetermined rate by comparing the noise signals it receives from the noise microphones (130), detecting a phase shift of the said noise pattern within the noise signals, determining an actual noise signal within the sound signal received from the main microphone (120) by calculating the phase shifts detected within the noise signals of the noise pattern according to the predetermined distances between the noise microphones (130), removing the actual noise signal from the audio signal.

Description

AUSCULTATION SYSTEM AND TECHNIQUE WITH NOISE REDUCTION TECHNIQUE
TECHNICAL FIELD
The present invention relates to an auscultation system comprising a digital stethoscope for detecting sounds within a body. The invention relates in detail to an auscultation system comprising a digital stethoscope with noise-reduction capability.
BACKGROUND
Auscultation is performed to listen to the sounds produced by the body. The auscultation process allows the sounds formed in a person's body to be heard through a stethoscope.
Digital stethoscopes transform analog sound waves formed within the body into digital sound waves by detecting them through a microphone. Digital stethoscopes include amplifiers to make the sound wave received through the microphone more distinguishable. In this way, low-power sound waves formed in the body are also detected through the microphone. Digital stethoscopes also ensure that the sounds that occur inside the body can be recorded and/or transferred to a remote terminal.
Digital stethoscopes strengthen the sound waves received by the microphone and also cause the noise signals received by the microphone to be strengthened. Noise signals may be erroneous signals received by the microphone or external sounds from the environment. These noise signals need to be separated from the sounds inside the body, which is the main target. For this reason, there are studies in the art to remove the noise signal in digital stethoscopes.
The noise-extracting studies known in the present art are performed by filtering the audio signal received by the microphone. Said filtering can be done according to signal strength and signal frequency. The sound waves that occur inside the body usually have low frequencies. For this reason, the sound signals in this frequency range can be filtered by performing frequency analysis of the sound waves formed in the body. Noise extraction in this way cannot give high performance when ambient noise is in the range close to the body sound frequency. The digital stethoscope may include an acoustic chamber for collecting sound waves in a target area. In this case, the power of the sound waves in the target area is increased by positioning the microphone in the acoustic chamber. In this case, it is ensured that the sound formed in the body is filtered by defining and removing the low-power audio signals as noise. However, this causes the low-power sound waves in the body to be ignored in the noise-generation process.
As a result, the above-mentioned issues have made it necessary to innovate in the related technical field.
BRIEF DESCRIPTION OF THE INVENTION
The present invention relates to an auscultation system for eliminating the above-mentioned disadvantages and bringing new advantages to the related technical field.
An object of the invention is to provide an auscultation system to provide listening with increased accuracy.
Another object of the invention is to provide a digital stethoscope to distinguish the sounds to be detected from the noises.
In order to achieve all the above-mentioned objects and those which will arise from the following detailed description, the present invention relates to a digital stethoscope for detecting sounds within the body, comprising an acoustic chamber for collecting sound waves occurring in a target area, a main microphone for detecting the sound in said acoustic chamber and a processor unit for processing the sound signal received by the said main microphone. Accordingly, it is characterized in that it comprises at least three noise microphones for detecting noise from outside the target zone, said noise microphones being positioned at a predetermined angle between them around an axis where the main microphone is the origin point, said processor unit being configured to perform the following process steps:
- simultaneously recording the sound signal received from the main microphone and the noise signals received from the noise microphones,
- determining a noise pattern if it detects a signal pattern match between the noise signals at a predetermined rate by comparing the noise signals it receives from the noise microphones,
- detecting a phase shift of the said noise pattern within the noise signals, - determining an actual noise signal within the sound signal received from the main microphone by calculating the phase shifts detected within the noise signals of the noise pattern according to the predetermined distances between the noise microphones,
- removing the actual noise signal from the audio signal.
Thus, it is ensured that the sounds formed in the target area are separated from the unwanted noises. In this way, the accuracy of the sounds in the target area to be listened to is increased. Likewise, the accuracy of the auscultation process is increased.
A possible embodiment of the invention is characterized in that said noise microphones are positioned at an equal angle between them around a circular axis in which the main microphone is the origin point. In this way, the accuracy of the noise pattern determined by the processor unit is increased. Thus, it is ensured that the voices formed in the target area are listened to with increased accuracy.
Another possible embodiment of the invention is characterized in that the distances between said noise microphones and the main microphone are equal. In this way, the accuracy of the actual noise pattern determined by the processor unit is increased. Thus, it is ensured that the voices formed in the target area are listened to with increased accuracy.
Another possible embodiment of the invention is characterized in that the processor unit is configured to detect a noise pattern of the noise signal it receives from the noise microphone.
Another possible embodiment of the invention is characterized in that the processor unit is configured to detect said noise pattern in the audio signal received from the main microphone.
Another possible embodiment of the invention is characterized in that the processor unit is configured to perform the process of removing said noise pattern from the audio signal.
Another possible embodiment of the invention is characterized in that the processor unit is configured to detect the noise signals received from the noise microphones using said noise pattern using a peak detection algorithm.
Another possible embodiment of the invention is characterized in that the main microphone is closer to the target area than the noise microphones. Thus, it is ensured that the main microphone perceives the sounds generated in the target area as more powerful than the noise microphones.
Another possible embodiment of the invention is characterized in that the main microphone is positioned at a focal point of the acoustic chamber. Thus, the main microphone is enabled to detect the sound waves in the target area in an amplified manner.
Another possible embodiment of the invention is characterized in that it is associated with a memory unit for recording the signals received by the processor unit.
Another possible embodiment of the invention is characterized in that the main microphone is a directional microphone. Thus, the main microphone can be directed to the target area. In this way, it is ensured that the main microphone perceives the sound waves in the target area in an amplified manner.
The present invention is also a digital stethoscope as described above, which relates to a method for filtering noise signals sensed by the main microphone. Accordingly, it is characterized in that the processor unit is configured to perform the following steps: a) simultaneously recording the sound signal received from the main microphone and the noise signals received from the noise microphones, b) determining a noise pattern if it detects a signal pattern match between the noise signals at a predetermined rate by comparing the noise signals it receives from the noise microphones, c) detecting a phase shift of the said noise pattern within the noise signals, d) determining an actual noise signal within the sound signal received from the main microphone by calculating the phase shifts detected within the noise signals of the noise pattern according to the predetermined distances between the noise microphones, e) removing the actual noise signal from the audio signal.
Another possible embodiment of the invention is characterized in that the processor unit is configured to use a peak detection algorithm in operation step "b". Thus, it is ensured that the processor unit determines the noise pattern with increased accuracy.
Another possible embodiment of the invention is characterized in that the processor unit is configured to use a triangulation algorithm in the processing step "d". Thus, it is ensured that the processor unit determines the actual noise pattern with increased accuracy. Another possible embodiment of the invention is characterized in that the processor unit is configured to calibrate the audio signal with a calibration constant after the operation step "e". Thus, the accuracy of the sounds generated in the target area of the processor unit is increased.
BRIEF DESCRIPTION OF THE FIGURES
Figure 1a shows a representative frontal view of the digital stethoscope.
Figure 1b shows a representative side view of the digital stethoscope.
Figure 2 shows a representative view of the configuration of the digital stethoscope.
Figure 3 shows a representative view of the auscultation system.
DETAILED DESCRIPTION OF THE INVENTION
In this detailed description, the auscultation system of the invention (10) is described only by way of non-limiting examples for a better understanding of the subject matter.
The invention relates to an auscultation system (10) for listening to sounds within a body. The auscultation system (10) provides instant listening or recording of the sounds in a target area to be listened to later or to be listened to remotely in telemedicine (remote health) applications.
The auscultation system (10) of the invention includes a digital stethoscope (100) for detecting sounds within a body. Said digital stethoscope (100) comprises an acoustic chamber (110) for collecting the sounds generated in a target area. Said acoustic chamber (110) has an acoustic structure to collect the sound waves formed in the target area in which it is directed. The digital stethoscope (100) includes a main microphone (120) for detecting sound within the acoustic chamber (110). The main microphone (120) generates an audio signal by sensing sound waves collected within the acoustic chamber (110). In a possible embodiment, the main microphone (120) is positioned at a focal point of the acoustic chamber (110). Thus, it is ensured that the sound waves collected in the acoustic chamber (110) are detected in a reinforced way by the main microphone (120). In a possible embodiment, the main microphone (120) is a directional microphone. In this way, the main microphone (120), which is directed to the target area, perceives the sounds generated in the target area in an amplified manner. The digital stethoscope (100) also includes a processor unit (140) for processing the audio signal generated by the main microphone (120). The main microphone (120) sends the audio signal it generates to the processor unit (140).
The digital stethoscope (100) of the invention comprises at least three noise microphones (130) for detecting noise from outside the target zone. The noise microphones (130) are positioned such that there is a predetermined angle between them around an axis where the main microphone (120) is the point of origin. The noise microphones (130) generate a noise signal according to the noise they detect and send said noise signal to the processor unit (140).
The object of the digital stethoscope (100) is to determine an actual noise signal based on the noise signals received by the processor unit (140) from the noise microphones (130) and to extract said actual noise signal from the audio signal received from the main microphone (120). Thus, it is ensured that the sound waves formed in the target area are listened to with increased accuracy.
The processor unit simultaneously records the audio signal received from the main microphone (120) and the noise signals received from the noise microphones (130). The processor unit (140) detects a predetermined ratio of signal pattern matching between the noise signals by comparing the noise signals it receives from the noise microphones (130). The positioning of the noise microphones (130) in such a way that there is a predetermined angle between them around an axis where the main microphone (120) is the point of origin creates a phase difference between the sound waves they perceive. For this reason, the noise signals produced by the noise microphones (130) have similar patterns and different phase angles. The processor unit (140) thus detects a predetermined matching of the signal pattern between the noise signals. The processor unit (140) determines a noise pattern according to the signal pattern matching. The processor unit (140) detects a phase shift of said noise pattern within the noise signals. That is, it detects the phase shift of the determined noise pattern within the noise signal produced by each noise microphone (130). In this way, the processor unit (140) detects by which noise microphone (130) the noise comes. Since the distance between the noise microphones (130) and the main microphone (120) is predetermined, the processor unit (140) determines an actual noise signal within the audio signal received from the main microphone (120). The processor unit (140) extracts the actual determined noise signal from the audio signal. Thus, it is ensured that the sound waves formed in the target area are separated from the noise sounds such as the external environment. Thus, it is ensured that the sound waves formed in the target area are listened to with increased accuracy.
The processor unit (140) is configured to perform the following steps, respectively: a) simultaneously recording the sound signal received from the main microphone (120) and the noise signals received from the noise microphones (130) b) determining a noise pattern if it detects a signal pattern match between the noise signals at a predetermined rate by comparing the noise signals it receives from the noise microphones (130) c) detecting a phase shift of the said noise pattern within the noise signals, d) determining an actual noise signal within the sound signal received from the main microphone (120) by calculating the phase shifts detected within the noise signals of the noise pattern according to the predetermined distances between the noise microphones (130) e) removing the actual noise signal from the audio signal.
The processor unit (140) uses a peak detection algorithm in operation step "b". Said peak determination algorithm is a pattern-matching algorithm in the state of the art. The peak detection algorithm detects a match between the noise signals by determining the maximum points of the noise signals. The processor unit (140) uses a triangulation algorithm in the "d" operation step. The aforementioned triangulation algorithm was created according to the mathematical method known as "triangulation" in the art. Using the triangulation algorithm, the processor unit (140) calculates the phase shifts detected within the noise signals of the noise pattern according to the predetermined distances between the noise microphones (130) and determines an actual noise signal within the audio signal received from the main microphone (120). The processor unit (140) calibrates the audio signal with a calibration constant after the "e" operation step. In this way, the audio signal is calibrated after the noises are separated from the audio signal received from the main microphone (120).
Referring to Figure 2, in a possible embodiment of the invention, the noise microphones (130) are positioned at an equal angle between them around a circular axis where the main microphone (120) is the point of origin. In this embodiment, the distances between the noise microphones (130) and the main microphone (120) are equal. Likewise, the noise microphones (130) are positioned at an angle of 120 degrees between them around a circular axis where the main microphone (120) is the point of origin. In a possible embodiment of the invention, the noise microphones (130) are positioned within the acoustic chamber (110) and at different points from the focal point of the acoustic chamber (110). In another embodiment, the acoustic noise microphones (130) are positioned outside or around the acoustic chamber (110).
The auscultation system (10) comprises a memory unit (150) associated with the processor unit (140) in a possible embodiment of the invention. The memory unit (150) allows the processor unit (140) to record the received signals. In this embodiment, the processor unit (140) has a machine-learning algorithm trained with the signals stored in the memory unit (150). Said machine learning algorithm increases the accuracy of the peak detection algorithm, triangulation algorithm, and calibration constant. In this way, the accuracy of the detection of the sounds formed in the target area is increased by the digital stethoscope (100).
The auscultation system (10) comprises a communication unit (160) associated with the processor unit (140) in a possible embodiment of the invention. Said communication unit (160) enables the digital stethoscope (100) to be connected to a communication network (170) and said communication network (170) enables the listening of the sounds detected by the digital stethoscope (100) by a mobile terminal (180). The communication unit (160) may be a Wi-Fi module known in the art. The communication network (170) is preferably a network such as the Internet. The mobile terminal (180) may be a device such as a tablet, phone, or computer connected to the communication network (170). In this way, a healthcare professional can connect to the communication network (170) via the mobile terminal (180) and listen to the sounds detected by the digital stethoscope (100) connected to the communication network (170) in a remote location. Likewise, the digital stethoscope (100) can record the detected sounds in a database. In this way, auscultation is performed remotely on sick people. In addition, auscultation data are recorded.
The digital stethoscope (100) may comprise amplifiers associated with the main microphone (120) and the noise microphones (130) in a possible embodiment of the invention. Said amplifiers amplify the sound waves perceived by the microphones as known in the art. In a possible embodiment, the digital stethoscope (100) may include transducers associated with the main microphone (120) and the noise microphones (130). Said transducers convert the sound waves perceived by the microphones from the analog signal to the digital signal as known in the art. In a possible embodiment, the digital stethoscope (100) may include filters associated with the main microphone (120) and the noise microphones (130). Said filters filter certain frequency ranges of the sound waves perceived by the microphones as known in the art.
Referring to Figure 2, in an example working scenario of the present invention, a first noise source (201) emits a noise. In this example, the target area to be listened to is out of the page. Here, the main microphone (120) positioned at the focal point of the acoustic chamber (110) generates an audio signal by sensing the sounds generated in the target area and the noise from the first noise source (201). The main microphone (120) detects the sounds generated in the target area more strongly than the noise from the first noise source (201). The noise microphones (130) also detect sounds from the target area and noise from the first noise source (201 ). Accordingly, it generates a noise signal. However, since the noise microphones (130) are positioned outside the acoustic chamber (110) or at a point different from the focal point, they detect the sounds coming from the target area at a negligible level. In this way, the noise microphones (130) only detect noise from the first noise source (201 ). In this example, the processor unit (140) simultaneously records the audio signal received from the main microphone (120) and the noise signals received from the noise microphones (130) to the memory unit (150). It then compares the noise signals using the peak detection algorithm and determines a noise pattern. It then detects the phase difference of the determined noise pattern with the noise signals. The phase difference here is due to the distance x+x between the second noise microphone (132) and the third noise microphone (133); the distance x between the second noise microphone (132) and the first noise microphone (131 ); the distance x between the first noise microphone (131 ) and the third noise microphone (133). In this way, the processor unit (140) detects that the first noise source (201) is located on the second noise microphone (132) side. Accordingly, since the distance between the noise microphones (130) and the main microphone (120) is defined in the processor unit (140), the processor unit (140) determines an actual noise pattern in the audio signal received from the main microphone (120). It then extracts the actual noise pattern from the audio signal. The actual noise pattern then calibrates the output audio signal with a calibration constant. Thus, it is ensured that the sounds formed in the target area are separated from the unwanted noises.
Referring to Figure 2, the difference of the present invention is that in a case study scenario, a second noise source (202) emits a noise. In this example, the target area to be listened to is outside of the page. Here, the main microphone (120) positioned at the focal point of the acoustic chamber (110) generates an audio signal by sensing the sounds generated in the target area and the noise from the second noise source (202). The main microphone (120) detects the sounds generated in the target area more strongly than the noise from the first noise source (201). The noise microphones (130) also detect sounds from the target area and noise from the second noise source (202). Accordingly, it generates a noise signal. However, since the noise microphones (130) are positioned outside the acoustic chamber (110) or at a point different from the focal point, they detect the sounds coming from the target area at a negligible level. In this way, the noise microphones (130) only detect noise from the second noise source (202). In this example, the processor unit (140) simultaneously records the audio signal received from the main microphone (120) and the noise signals received from the noise microphones (130) to the memory unit (150). It then compares the noise signals using the peak detection algorithm and determines a noise pattern. It then detects the phase difference of the determined noise pattern with the noise signals. The phase difference here is due to the z+y distance between the first noise microphone (131) and the second noise microphone (132); the z+y distance between the first noise microphone (131 ) and the third noise microphone (133). Since there is no vertical distance difference between the second noise microphone (132) and the second noise source (202) of the third noise microphone (133), there is no phase difference between the noise signals generated by the second noise microphone (132) and the third noise microphone (133). In this way, the processor unit (140) detects that the second noise source (202) is located on the side of the first noise microphone (131 ). Accordingly, since the distance between the noise microphones (130) and the main microphone (120) is defined in the processor unit (140), the processor unit (140) determines an actual noise pattern in the audio signal received from the main microphone (120). It then extracts the actual noise pattern from the audio signal. The actual noise pattern then calibrates the output audio signal with a calibration constant. Thus, it is ensured that the sounds formed in the target area are separated from the unwanted noises.
The protection scope of the invention is specified in the appended claims and certainly cannot be limited to what is described in this detailed description for illustrative purposes. It is clear that those skilled in the art can produce similar embodiments in the light of the foregoing without departing from the main theme of the invention.
REFERENCE NUMBERS GIVEN IN THE FIGURE
10 Auscultation system
100 Digital stethoscope
110 Acoustic chamber
120 Main microphone
130 Noise microphone
131 First noise microphone
132 Second noise microphone
133 Third noise microphone
140 Processor unit
150 Memory unit
160 Communication unit
170 Communication network
180 Mobile terminal
201 First noise source
202 Second noise source
D: Circular axis
X: Vertical projection of the distance between the second noise microphone and the main microphone on the horizontal axis and vertical projection of the distance between the third noise microphone and the main microphone on the horizontal axis
Y: Vertical projection of the distance between the second noise microphone and the main microphone on the vertical axis and vertical projection of the distance between the third noise microphone and the main microphone on the vertical axis
Z: Vertical projection of the distance between the first noise microphone and the main microphone on the vertical axis

Claims

1. A digital stethoscope (100) for detecting sounds within the body comprising an acoustic chamber (110) for collecting sound waves occurring in a target area, a main microphone (120) for sensing sound within the said acoustic chamber (110), and a processor unit (140) for processing the sound signal received by said main microphone (120), characterized in that; it comprises at least three noise microphones (130) for sensing noise from outside the target area, said noise microphones (130) being positioned at a predetermined angle between them around an axis where the main microphone (120) is the origin point, said processor unit (140) being configured to perform the following steps:
- simultaneously recording the sound signal received from the main microphone (120) and the noise signals received from the noise microphones (130),
- determining a noise pattern if it detects a signal pattern match between the noise signals at a predetermined rate by comparing the noise signals it receives from the noise microphones (130),
- detecting a phase shift of the said noise pattern within the noise signals,
- determining an actual noise signal within the sound signal received from the main microphone (120) by calculating the phase shifts detected within the noise signals of the noise pattern according to the predetermined distances between the noise microphones (130),
- removing the actual noise signal from the audio signal.
2. A digital stethoscope (100) according to Claim 1 , characterized in that said noise microphones (130) are positioned at an equal angle between them around a circular axis where the main microphone (120) is the origin point.
3. A digital stethoscope (100) according to Claim 1 , characterized in that the distances between said noise microphones (130) and the main microphone (120) are equal.
4. A digital stethoscope (100) according to Claim 1 , characterized in that the processor unit (140) is configured to detect a noise pattern of the noise signal it receives from the noise microphone (130).
5. A digital stethoscope (100) according to Claim 4, characterized in that the processor unit (140) is configured to detect said noise pattern in the audio signal it receives from the main microphone (120).
6. A digital stethoscope (100) according to Claim 5, characterized in that the processor unit (140) is configured to perform the process of removing the noise pattern from the audio signal.
7. A digital stethoscope (100) according to Claim 4, characterized in that the processor unit (140) is configured to detect the noise signals received from the noise microphones (130) using a peak detection algorithm.
8. A digital stethoscope (100) according to Claim 1 , characterized in that the main microphone (120) is closer to the target area than the noise microphones (130).
9. A digital stethoscope (100) according to Claim 1 , characterized in that the main microphone (120) is positioned at a focal point of the acoustic chamber (110).
10. A digital stethoscope (100) according to Claim 1 , characterized in that it is associated with a memory unit (150) to record the signals received by the processor unit (140).
11. A digital stethoscope (100) according to Claim 1 , characterized in that the main microphone (120) is a guided microphone.
12. A digital stethoscope (100) according to Claim 1 , a method for filtering noise signals detected by the main microphone (120), characterized in that the processor unit (140) is configured to perform the following steps: a. simultaneously recording the sound signal received from the main microphone (120) and the noise signals received from the noise microphones (130), b. determining a noise pattern if it detects a signal pattern match between the noise signals at a predetermined rate by comparing the noise signals it receives from the noise microphones (130), c. detecting a phase shift of the said noise pattern within the noise signals, d. determining an actual noise signal within the sound signal received from the main microphone (120) by calculating the phase shifts detected within the noise signals of the noise pattern according to the predetermined distances between the noise microphones (130), e. removing the actual noise signal from the audio signal. A method according to Claim 12, characterized in that the processor unit (140) is configured to use a peak detection algorithm in the process step "b". A method according to Claim 12, characterized in that the processor unit (140) is configured to use a triangulation algorithm in the process step "d". A method according to Claim 12, characterized in that the processor unit (140) is configured to calibrate the audio signal with a calibration constant after the process step "e".
PCT/TR2023/050506 2022-06-09 2023-06-01 Auscultation system and technique with noise reduction technique WO2023239326A1 (en)

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WO2011056856A1 (en) * 2009-11-04 2011-05-12 West Wireless Health Institute Microphone arrays for listening to internal organs of the body
KR101407049B1 (en) * 2013-01-16 2014-06-24 이병훈 An apparatus and method of extracting body signals from signals including noise signals and detected by a stethoscope
US20160015359A1 (en) * 2014-06-30 2016-01-21 The Johns Hopkins University Lung sound denoising stethoscope, algorithm, and related methods
WO2019067880A1 (en) * 2017-09-28 2019-04-04 Heroic Faith Medical Science Co., Ltd. Network-connected electronic stethoscope systems
WO2021131585A1 (en) * 2019-12-27 2021-07-01 テルモ株式会社 Sound detection system and information processing device

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011056856A1 (en) * 2009-11-04 2011-05-12 West Wireless Health Institute Microphone arrays for listening to internal organs of the body
KR101407049B1 (en) * 2013-01-16 2014-06-24 이병훈 An apparatus and method of extracting body signals from signals including noise signals and detected by a stethoscope
US20160015359A1 (en) * 2014-06-30 2016-01-21 The Johns Hopkins University Lung sound denoising stethoscope, algorithm, and related methods
WO2019067880A1 (en) * 2017-09-28 2019-04-04 Heroic Faith Medical Science Co., Ltd. Network-connected electronic stethoscope systems
WO2021131585A1 (en) * 2019-12-27 2021-07-01 テルモ株式会社 Sound detection system and information processing device

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