TWI811919B - Audio playback apparatus and positioning method - Google Patents

Abstract

An audio playback apparatus and a positioning method are provided. The audio playback apparatus includes two sound receivers and two speakers. A horizontal direction of an object relative to the audio playback apparatus is determined according to a first detecting sound signal with fixed high frequency. A travel distance of a second detecting sound signal with linear-variable high frequency after reflecting by the object is determined. The travel distance starts from the speaker, passes the object, and then arrives at the two sound receivers. The vertical degree of the object relative to the audio playback apparatus is determined according to the distance difference between travel distances of the second detecting sound signal which arrive at two sound receivers respectively. The separating distance between the object and the audio playback apparatus is determined according to the horizontal direction, the travel distance, and the vertical degree. Accordingly, the positioning is achieved with high-frequency sound signals.

Description

Sound playback device and positioning method

The present invention relates to sound signal processing, and in particular, to a sound playing device and a sound-based positioning method.

Laptop computers are usually equipped with cameras and can detect whether the user is nearby through image recognition technology. On the other hand, somatosensory control is also one of the technologies that has developed rapidly in recent years. For example, the user uses special gestures (eg, waving to the left or waving to the right) to control functions of the notebook computer. Although object detection technology based on image recognition can provide higher recognition accuracy, it may consume more power.

In view of this, embodiments of the present invention provide a sound playback device and a positioning method that can use existing receivers and speakers on the device to detect objects.

The positioning method according to the embodiment of the present invention is suitable for sound playback devices. The sound playback device includes two radios and two speakers. The positioning method includes (but is not limited to) the following steps: determining the horizontal direction of the object relative to the sound playback device based on the first detected sound signal. The first detection sound signal is a high-frequency sound signal with a fixed frequency. The first detection sound signal is played through the first speaker of the two speakers and recorded through the two radios. Determine the travel distance of the second detection sound signal reflected by the object. The second detection sound signal is a high-frequency sound signal whose frequency changes linearly. The second detection sound signal is played through the second speaker of the two speakers and recorded through the two radios. The travel distance is from the second speaker and passes through the object to the second radio. The vertical angle of the object relative to the sound playback device is determined based on the distance difference between the travel distances of the second detected sound signal to the two microphones respectively. The separation distance of the object relative to the sound playback device is determined based on the horizontal direction, travel distance and vertical angle.

The sound playback device according to the embodiment of the present invention includes (but is not limited to) two receivers, two speakers and a processor. A radio is used to pick up sound. Speakers are used to play sounds. The processor is coupled to two radios and two speakers. The processor is configured to determine the horizontal direction of the object relative to the sound playback device based on the first detection sound signal, determine the travel distance of the second detection sound signal reflected by the object, and determine the travel distance of the second detection sound signal to the two receivers based on the second detection sound signal. The distance difference between them determines the vertical angle of the object relative to the sound playing device, and the separation distance of the object relative to the sound playing device is determined based on the horizontal direction, travel distance and vertical angle. The first detection sound signal is a high-frequency sound signal with a fixed frequency. The first detection sound signal is played through the first speaker of the two speakers and recorded through the two receivers. The second detection sound signal is a high-frequency sound signal whose frequency changes linearly. The second detection sound signal is played through the second speaker of the two speakers and recorded through the two radios. The travel distance is from the second speaker and passes through the object to the second radio.

Based on the above, according to the sound playback device and the positioning method according to the embodiment of the present invention, high-frequency detection sound signals with different frequency settings are played through the speakers, and the object is located based on the sound signals recorded by the radio. In this way, an energy-saving and convenient positioning mechanism can be provided, and high-frequency signals will not affect the user's general listening usage.

In order to make the above-mentioned features and advantages of the present invention more obvious and easy to understand, embodiments are given below and described in detail with reference to the accompanying drawings.

FIG. 1 is a component block diagram of a sound playing device 10 according to an embodiment of the present invention. Referring to FIG. 1 , the sound playing device 10 includes (but is not limited to) receivers 11 and 12 , speakers 13 and 14 , a memory 17 and a processor 19 . The sound playing device 10 may be a notebook computer, a smart phone, a tablet computer, a desktop computer, a smart TV, a smart speaker or other electronic devices.

The receivers 11 and 12 may be dynamic, condenser, or electret condenser type microphones. The receivers 11 and 12 may also be other types of microphones that can receive sound waves (for example, human voice). , environmental sound, machine operation sound, etc.) (i.e., radio or recording), a combination of electronic components, analog-to-digital converters, filters, and audio processors that are converted into sound signals. In some embodiments, the receivers 11, 12 may be microphones such as a smartphone, a voice recorder, or a laptop computer. In one embodiment, two microphones 11, 12 or more microphones form a microphone array.

The speakers 13, 14 may be speakers or amplifiers. In one embodiment, one or both of the speakers 13 and 14 are built into the body of the sound playing device 10 . In another embodiment, one or both of the speakers 13 and 14 are not built into the body of the sound playing device 10 . For example, a desktop console has external speakers. In one embodiment, the speakers 13 and 14 are used to play sounds.

The memory 17 can be any type of fixed or removable random access memory (Radom Access Memory, RAM), read only memory (Read Only Memory, ROM), flash memory (flash memory), traditional hard disk (Hard Disk Drive, HDD), solid-state drive (Solid-State Drive, SSD) or similar components. In one embodiment, the memory 17 is used to store program codes, software modules, configurations, data (such as sound signals, distance, time, frequency, angle or beam field type parameters) or files for subsequent implementation. Example details.

The processor 19 is coupled to the receivers 11 and 12, the speakers 13 and 14 and the memory 17. The processor 19 may be a central processing unit (CPU), a graphics processing unit (GPU), or other programmable general-purpose or special-purpose microprocessor (Microprocessor), digital signal processing Digital Signal Processor (DSP), programmable controller, Field Programmable Gate Array (FPGA), Application-Specific Integrated Circuit (ASIC) or other similar components or A combination of the above elements. In some embodiments, the functions of processor 19 may be implemented in software or integrated circuits. In one embodiment, the processor 19 is used to execute all or part of the operations of the sound playback device 10 and can load and execute each software module, file and data stored in the memory 17 .

FIG. 2 is a schematic diagram of a sound playing device 10 according to an embodiment of the present invention. Referring to FIG. 2 , the sound playing device 10 takes a notebook computer as an example. The receivers 11 and 12 are located on the top side of surface B of the sound playing device 10 . The speakers 13 and 14 are located on both front sides between the C surface and the D surface of the sound playing device 10 . A coordinate system with the midpoint between microphones 11 and 12 as the center point/origin, where r in the coordinates (r, θ, φ) is the distance from the center point, and θ is the horizontal reference line relative to the horizontal reference line ( For example, the angle of a horizontal line passing through the midpoint between microphones 11,12), and φ is the angle in the vertical plane with respect to a vertical reference line (e.g., a vertical line passing through the midpoint between microphones 11,12) angle (or tilt angle). The coordinates of the radios 11 and 12 are (d _m /2,90∘,0∘) and (d _m /2,90∘,0∘) respectively. The coordinates of speakers 13 and 14 are (r ₁ , θ ₁ , φ ₁ ) and (r ₂ , θ ₂ , φ ₂ ) respectively.

It should be noted that the implementation manner and component locations shown in FIG. 2 are only used as examples, and the embodiments of the present invention are not limited thereto.

In the following, the method described in the embodiment of the present invention will be described with reference to various devices, components and modules in the sound playback device 10 . Each process of this method can be adjusted according to the implementation situation, and is not limited thereto.

Figure 3 is a flow chart of a positioning method according to an embodiment of the present invention. Referring to FIG. 3 , the processor 19 determines the horizontal direction of the object relative to the sound playing device 10 based on the first detected sound signal (step S310 ). Specifically, the processor 19 plays the first detection sound signal through one of the speakers 13 and 14 (taking the speaker 13 as an example). The first detection sound signal is a high-frequency sound signal with a fixed frequency. High frequencies may be frequencies above 18 kilohertz (kHz). That is to say, the first detection sound signal maintains the same high frequency. For example, the first detection sound signal is fixed at 18 kHz frequency. On the other hand, during the process of playing the first detection sound signal, the processor 19 records/receives sound through the receivers 11 and 12 .

Taking FIG. 2 as an example, assume that there is an object O (for example, a face or a hand) located at coordinates (r ₀ , θ _O , φ _O ), which means that the angle of the object O relative to the horizontal direction of the sound playback device 10 is θ _O . It should be noted that the center point between the receivers 11 and 12 in FIG. 2 is used as the representative point of the sound playback device 10 below, but the user can still change the position of the representative point according to actual needs.

There are many ways to determine the horizontal direction. In one embodiment, the processor 19 forms beams at multiple pointing angles through the microphones 11 and 12 respectively. The radios 11 and 12 form beams based on beamforming technology. Beamforming allows signals at certain angles to obtain constructive interference and signals at other angles to obtain destructive interference by adjusting the parameters of the basic units of the phase array (for example, phase and amplitude). Therefore, different parameters will form different beam patterns, and the pointing angles of the main beams may be different. The processor 19 may predefine or generate multiple pointing angles based on user input operations. For example, every interval of 10∘ between -90∘ and 90∘ is used as the pointing angle.

During the process of playing the first detection sound signal, every time it switches to a specific pointing angle, the processor 19 measures the signal power obtained by the beam collection at the current pointing angle through the microphones 11 and 12 . The processor 19 can determine the horizontal direction based on the signal power obtained through the beam collection at those pointing angles, and the horizontal direction is related to the pointing angle of the one with higher signal power. For example, the processor 19 defines a power threshold and determines whether the signal power corresponding to each pointing angle is greater than the power threshold. If the signal power corresponding to the pointing angle is greater than the signal threshold, the processor 19 can determine that there is an object O at the pointing angle, and use the pointing angle as the horizontal angle of the object O relative to the sound playing device 10 . If the signal power corresponding to the pointing angle is not greater than the signal threshold, the processor 19 can determine that there is no object O at the pointing angle. For another example, the processor 19 selects one or a specific number of pointing angles with the highest signal power as the horizontal angle. It should be noted that the signal threshold can be determined in advance based on experiments or preset information, and may change based on actual needs. For example, the signal threshold used at the angle θ ₁ where the speaker 13 that plays the first detection sound signal is different from the signal thresholds at other pointing angles.

In another embodiment, the horizontal direction of the object O relative to the sound playing device 10 may be estimated based on an angle of arrival (AOA or DOA) positioning technology. For example, the processor 19 may determine the horizontal direction based on the time difference between the two sound waves of the first detected sound signal reaching the microphones 11 and 12 respectively after being reflected by the object O and the distance d _m between the two microphones 11 and 12 .

The processor 19 may determine the travel distance of the second detection sound signal reflected by the object O (step S330). Specifically, the processor 19 plays the second detection sound signal through the other one of the speakers 13 and 14 (taking the speaker 14 as an example). Different from the first detection sound signal, the second detection sound signal is a high-frequency sound signal whose frequency changes linearly. For example, the second detected sound signal is a chirp signal using Linear Frequency Modulation (LFM) technology. FIG. 4 is a frequency-time diagram of a detected sound signal according to an embodiment of the present invention. Referring to FIG. 4 , the frequency of the first detection sound signal DS1 is fixed, and the frequency of the second detection sound signal DS2 changes with time. On the other hand, during the process of playing the second detection sound signal, the processor 19 records/receives sound through the receivers 11 and 12 .

Regarding the travel distance, FIG. 5 is a schematic diagram of the travel distance according to an embodiment of the present invention. Referring to FIG. 5 , the travel distance x ₁ originates from the speaker 14 and passes through the object O before reaching the receiver 11 . Since the second detection sound signal will be reflected when it reaches the object O, the transmission path of the second detection sound signal can be regarded as a straight path from the virtual speaker VS to the microphone 11 , where the distance between the virtual speaker VS and the object O is the same as the distance between the virtual speaker VS and the object O 14 and the object O, and the virtual speaker VS is located at the extension of the straight line formed by the object O and the receiver 11. That is to say, the sound signal recorded by the receiver 11 and broadcast by the speaker 14 and reflected by the object O is like the sound signal emitted by the sound source where the virtual speaker VS is located.

Since the frequency of the second detected sound signal changes linearly with time, the travel time of the sound signal can be estimated based on the frequency difference between the radio signal and the broadcast signal, and the travel path can be known accordingly. In one embodiment, the processor 19 may compare the first frequency difference between the first radio signal and the second detected sound signal collected by the microphone 11/12. This first radio signal corresponds to the path traveled distance. For example, it is a path with a distance x ₁ as shown in Figure 4 . That is, the second detection sound signal originates from the speaker 14 and passes through the object O before reaching the receiver 11 . On the other hand, the line segment at the angle θ _O (indicating that it corresponds to the object O) shown in FIG. 4 corresponds to the first radio signal, and the processor 19 can obtain the first frequency difference. .

The processor 19 can determine the traveling distance based on the first frequency difference and the frequency modulation slope of the second detected sound signal. The frequency modulation slope is the frequency linear change slope of the second detected sound signal. For example, the travel distance x ₁ is: …(1) Among them, C is the speed of sound, and s is the frequency modulation slope. In the same way, the path x ₂ of the second detected sound signal originating from the speaker 14 and passing through the object O before reaching the radio receiver 12 can be obtained based on the first radio signal received by the radio 12 and the corresponding first frequency difference, so No further details will be given here.

In one embodiment, the system delay of sound playback is considered. The processor 19 can compare the second frequency difference between the second radio signal collected by the microphone 11/12 and the second detected sound signal. The second radio signal corresponds to the path directly from the speaker 14 to the microphone 11/12 (for example, the distance r ₂ in Figure 1 or Figure 5 and shorter than the path distance x ₁ ), so the first radio signal is compared with the second radio signal. The signal was received later by the radio on 11/12. On the other hand, the line segment with the angle θ ₂ shown in FIG. 4 (corresponding to the speaker 14 ) corresponds to the second radio signal, and the processor 19 can obtain the second frequency difference. .

Based on the frequency modulation slope, the processor 19 may and the distance r ₂ between the speaker 14 and the receiver 11/12 determines the system delay time . For example, system latency for: …(2)

Then, the processor 19 can determine the travel distance x ₁ /x ₂ according to the travel time of the second detected sound signal. The travel time is the time difference between the change time and the system delay time, and the change time is the first frequency difference The time at frequency modulation slope s. For example, the distance x ₁ of the second detection sound signal from the speaker 14 to the receiver 11 is: …(3) where the travel time is , and the change time is . Similarly, the processor 19 can determine the travel distance x ₂ of the second detected sound signal from the speaker 14 to the receiver 12 .

The processor 19 determines the vertical angle of the object O relative to the sound playing device 10 based on the distance difference between the travel distances of the second detected sound signal to the two microphones 11 and 12 respectively (step S350). Specifically, FIG. 6 is a schematic diagram of a vertical angle according to an embodiment of the present invention. Please refer to Figure 6. If there is only the travel distance and the angle in the horizontal direction, then we can only know any position of the arc C formed by the object O in the horizontal direction and the corresponding travel distance away from the microphones 11 and 12. Therefore, the vertical angle φ _O needs to be further determined. The processor 19 can Determine the vertical angle : …(4)

The processor 19 determines the separation distance of the object O relative to the sound playing device 10 based on the horizontal direction, travel distance and vertical angle (step S370). Specifically, FIG. 7 is a schematic diagram of a triangle according to an embodiment of the present invention. Referring to FIG. 7 , the processor 19 can determine the first distance x _{0 -r 0 and} the second distance r ₀ based on the (representative) travel distance x 0 . The representative travel distance of the second detection sound signal is, for example, the average value, the maximum value, or one of the travel distances x ₁ and x ₂ of the second detection sound signal to the microphones 11 and 12 respectively. The first distance x ₀ -r ₀ is the distance between the speaker 14 and the object O, the second distance r ₀ is the separation distance between the object O and the sound playback device 10 , and the first distance x ₀ -r ₀ and the second distance r 0 The sum of the distances r ₀ represents the travel distance x ₀ .

The processor 19 can determine the distance between the first distance x ₀ -r ₀ , the second distance r ₀ and the distance between the speaker 14 and the microphone 11/12 (for example, the distance r ₁ , r ₂ in FIG. 1 or their average value). The triangle TRI formed determines the separation distance (ie, the second distance r ₀ ). The angle α corresponding to the first distance x ₀ -r ₀ in the triangle TRI is related to the horizontal direction θ _O and the vertical angle φ _O . For example, the processor 19 can use the cosine theorem of triangles to deduce: …(5) …(6)

To sum up, in the sound playback device and positioning method of the embodiment of the present invention, the speaker is used to play the detection sound signals of fixed frequency and linearly varying frequency respectively, and the time difference, frequency difference and signal of the sound signal recorded by the radio are The power gives the object's position in space relative to the sound player. In this way, the speakers and receivers installed in most electronic devices can be used to achieve the positioning function, and the high-frequency sound will not affect the user's listening to other audio files or sound streams.

Although the present invention has been disclosed above through embodiments, they are not intended to limit the present invention. Anyone with ordinary knowledge in the technical field may make some modifications and modifications without departing from the spirit and scope of the present invention. Therefore, The protection scope of the present invention shall be determined by the appended patent application scope.

10: Sound playback device 11, 12: Radio 13, 14: Speaker 17: Memory 19: Processor O: Object d _m , r ₂ : Distance θ ₀ , θ ₁ , θ ₂ , φ ₀ , φ ₁ , φ ₂ : Angle S310~S370: Step DS1: First detection sound signal DS2: Second detection sound signal x ₁ : Travel distance VS: Virtual speaker :First frequency difference :Second frequency difference :Distance difference TRI:Triangle x ₀ :Travel distance x ₀ -r ₀ :First distance r ₀ :Second distance

FIG. 1 is a component block diagram of a sound playing device according to an embodiment of the present invention. FIG. 2 is a schematic diagram of a sound playing device according to an embodiment of the present invention. Figure 3 is a flow chart of a positioning method according to an embodiment of the present invention. FIG. 4 is a frequency-time diagram of a detected sound signal according to an embodiment of the present invention. FIG. 5 is a schematic diagram of travel distance according to an embodiment of the present invention. FIG. 6 is a schematic diagram of a vertical angle according to an embodiment of the present invention. Figure 7 is a schematic diagram of a triangle according to an embodiment of the present invention.

S310~S370: steps

Claims (8)

A positioning method suitable for a sound playback device. The sound playback device includes two radios and two speakers. There is a distance between the two radios. The positioning method includes: based on a first detected sound signal at multiple angles. The intensity determines a horizontal direction of an object relative to the sound playing device, wherein the first detection sound signal is a high-frequency sound signal of a fixed frequency, and the first detection sound signal is played through a first speaker among the two speakers. Recording through the two radios; comparing a first frequency difference between a first radio signal and a second detection sound signal obtained by the two radios, and determining the frequency reflected by the object based on the first frequency difference A travel distance, wherein the first radio signal corresponds to the path of the travel route, the second detection sound signal is a high-frequency sound signal with a linear change in frequency, and the second detection sound signal is transmitted through a second of the two speakers. The speaker plays and records through the two radios, and the travel distance originates from the second speaker and passes through the object before reaching the two radios; according to the travel distance of the second detection sound signal to the two radios respectively A distance difference between determines a vertical angle of the object relative to the sound playback device, where

φ _O is the vertical angle, △x is the distance difference, d _m is the distance between the two radios, θ ₀ is the angle of the object relative to the horizontal direction of the sound playback device; and according to the horizontal direction , the traveling distance and the vertical angle determine a separation distance of the object relative to the sound playback device, including: determining a first distance and a second distance based on the traveling distance, wherein the first distance is between the second speaker and The distance between the objects, the second distance is the separation distance, and the sum of the first distance and the second distance is the travel distance; and based on the first distance, the second distance and the second speaker and A triangle formed by the distance between the two microphones determines the separation distance, wherein the angle in the triangle corresponding to the first distance is related to the horizontal direction and the vertical angle. The positioning method of claim 1, wherein the step of determining the travel distance of the second detection sound signal reflected by the object includes: determining the travel distance based on the first frequency difference and a frequency modulation slope of the second detection sound signal distance, wherein the frequency modulation slope is the frequency linear change slope of the second detected sound signal. The positioning method of claim 2, wherein the step of determining the travel distance based on the first frequency difference and the frequency modulation slope of the second detected sound signal includes: comparing a second radio signal obtained by the two radios. and a second frequency difference between the second detected sound signal, wherein the first radio signal is received later than the second radio signal, and the second radio signal corresponds to the second speaker and is directly transmitted to the two The path of the radio; determining a system delay time based on the second frequency difference and the distance between the second speaker and the two radios; and The travel distance is determined based on a travel time of the second detected sound signal, where the travel time is a time difference between a change time and the system delay time, and the change time is the time of the first frequency difference under the frequency modulation slope. . The positioning method according to claim 1, wherein the step of determining the horizontal direction of the object relative to the sound player device based on the first detected sound signal includes: forming beams with multiple pointing angles through the two receivers; and The horizontal direction is determined based on the signal power obtained through the beam collection at these pointing angles, wherein the horizontal direction is related to the pointing angle of the signal with higher power. A sound playing device, including: two radios, with a distance between them, and used to collect sounds; two speakers, used to play sounds; and a processor, coupled to the two radios and the two speakers, and configured Used to: determine a horizontal direction of an object relative to the sound playback device based on the signal strength of a first detection sound signal at multiple angles, wherein the first detection sound signal is a high-frequency sound signal of a fixed frequency, and the first detection sound signal is a fixed-frequency high-frequency sound signal. The detection sound signal is played through a first speaker among the two speakers and recorded through the two radios; a first radio signal and a second detection sound signal obtained by the two radios are compared. frequency difference, and determine a travel distance reflected by the object based on the first frequency difference, where the first radio signal corresponds to the path of the travel route, and the second detection sound signal is a high-frequency sound signal with a linear change in frequency, The second detection sound signal is played through a second speaker among the two speakers and recorded through the two radios, and the travel distance originates from the second speaker and passes through the object before reaching the two radios; according to the A distance difference between the travel distances of the second detected sound signals to the two receivers determines a vertical angle of the object relative to the sound playback device, wherein

φ _O is the vertical angle, △x is the distance difference, d _m is the distance between the two radios, θ ₀ is the angle of the object relative to the horizontal direction of the sound playback device; and according to the horizontal direction , the traveling distance and the vertical angle determine a separation distance of the object relative to the sound playback device, including: determining a first distance and a second distance based on the traveling distance, wherein the first distance is between the second speaker and The distance between the objects, the second distance is the separation distance, and the sum of the first distance and the second distance is the travel distance; and based on the first distance, the second distance and the second speaker and A triangle formed by the distance between the two microphones determines the separation distance, wherein the angle in the triangle corresponding to the first distance is related to the horizontal direction and the vertical angle. The sound playback device of claim 5, wherein the processor is further configured to: determine the travel distance based on the first frequency difference and a frequency modulation slope of the second detected sound signal, wherein the frequency modulation slope is the third frequency modulation slope. 2. Frequency line for detecting sound signals slope of sexual change. The sound playback device of claim 6, wherein the processor is further configured to: compare a second frequency difference between a second radio signal collected by the two radios and the second detection sound signal. , wherein the first radio signal is received later than the second radio signal, and the second radio signal corresponds to the path directly from the second speaker to the two radios; according to the second frequency difference and the third The distance between the two speakers and the two receivers determines a system delay time; and the travel distance is determined based on a travel time of the second detected sound signal, wherein the travel time is the time difference between a change time and the system delay time , and the change time is the time of the first frequency difference under the frequency modulation slope. The sound playback device of claim 5, wherein the processor is further configured to: form beams with multiple directional angles through the two radios; and based on the signal power obtained through the beam collection at these directional angles. Determine the horizontal direction, where the horizontal direction is related to the pointing angle of the signal with higher power.

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