TWI633275B - Distance detection device and distance detection method thereof - Google Patents

Abstract

A distance detecting device and a distance detecting method thereof. Performing a cross-correlation operation between the sound signal received by the sound receiver and the preset sound signal to generate a cross-correlation signal, and outputting a preset sound signal according to a time point of the speaker and a first sound receiving corresponding to the first peak in the cross-correlation signal The first distance and the second distance are calculated for the time and the second sound receiving time corresponding to the second peak, and the distance between the sound receiver and the reflector is calculated according to the first distance and the second distance.

Description

Distance detecting device and distance detecting method thereof

The present invention relates to a detecting device, and more particularly to a distance detecting device and a distance detecting method thereof.

In general, finding a coordinate position in a three-dimensional space requires a lot of microphones. For example, when there is only one speaker as a signal source, more than four microphones are needed to pass the distance between each microphone and the speaker and the microphones. The distance to calculate the three-dimensional position of a particular microphone.

The invention provides a distance detecting device and a distance detecting method thereof, which can reduce the number of sound receivers required for distance measurement.

The distance detecting device of the present invention includes a speaker, a sound receiver, and a processor. The speaker is disposed on one side of the reflector, and outputs a preset sound signal, a reflector The preset sound signal is reflected to generate a reflected sound signal. The processor cross-correlates the sound signal received by the sound receiver with the preset sound signal to generate a cross-correlation signal, wherein the cross-correlation signal includes a first peak corresponding to the preset sound signal and a second corresponding to the reflected sound signal a peak, the processor calculates a first distance and a second distance according to a time point at which the speaker outputs the preset sound signal, a first sound receiving time corresponding to the first peak, and a second sound receiving time corresponding to the second peak, and according to the first distance And the second distance calculates the distance between the sound receiver and the reflector.

In an embodiment of the invention, the first distance is a distance between the sound receiver and the speaker, the second distance is a distance between the sound receiver and the virtual speaker, and the speaker and the virtual speaker are symmetric with respect to the reflector, and the speaker A third distance from the virtual speaker, the processor calculates the distance between the sound receiver and the reflector in the normal direction of the reflector according to the first distance, the second distance, and the third distance.

In an embodiment of the invention, the preset sound signal has a time-varying amplitude and frequency, and the first low-pass filtered signal obtained by the low-pass filtering of the preset sound signal has a time between the first low-pass filtered signal and the preset sound signal. a difference, the processor low-pass filtering the sound signal received by the sound receiver to generate a second low-pass filtered signal, and the processor predicts the sound receiver to receive the preset according to the time difference value and the second low-pass filtered signal The time when the sound signal is reflected and the sound signal is reflected.

In an embodiment of the invention, the time difference is a time difference between a time when the speaker outputs the peak amplitude of the packet of the preset sound signal and a peak of the packet amplitude of the first low-pass filtered signal.

In an embodiment of the invention, the low pass filtering is an infinite impulse Should be filtered.

In an embodiment of the invention, the cross-correlation operation described above is a fast cross-correlation operation.

The invention also provides a distance detecting method for a distance detecting device. The distance detecting device comprises a speaker and a sound receiver. The speaker is disposed on one side of the reflecting plate for outputting a preset sound signal, and the reflecting plate reflects the preset sound signal. The method for detecting the distance of the distance detecting device includes the following steps. The sound signal received by the sound receiver is cross-correlated with the preset sound signal to generate a cross-correlation signal, wherein the cross-correlation signal includes a first peak corresponding to the preset sound signal and a second peak corresponding to the reflected sound signal. The first distance and the second distance are calculated according to a time point at which the speaker outputs the preset sound signal, a first sound receiving time corresponding to the first peak, and a second sound receiving time corresponding to the second peak. The distance between the sound receiver and the reflector is calculated based on the first distance and the second distance.

In an embodiment of the invention, the first distance is a distance between the sound receiver and the speaker, the second distance is a distance between the sound receiver and the virtual speaker, and the speaker and the virtual speaker are symmetric with respect to the reflector, and the speaker A third distance from the virtual speaker, the distance detecting method of the distance detecting device comprises: calculating the distance between the sound receiver and the reflector in the normal direction of the reflector according to the first distance, the second distance, and the third distance .

In an embodiment of the invention, the preset sound signal has a time-varying amplitude and frequency, and the first low-pass filter obtained by the low-pass filtering of the preset sound signal There is a time difference between the wave signal and the preset sound signal, and the distance detecting method of the distance detecting device includes the following steps. The sound signal received by the sound receiver is low pass filtered to produce a second low pass filtered signal. The time when the sound receiver receives the preset sound signal and the reflected sound signal is estimated according to the time difference value and the second low-pass filtered signal.

In an embodiment of the invention, the time difference is a time difference between a time when the speaker outputs the peak amplitude of the packet of the preset sound signal and a peak of the packet amplitude of the first low-pass filtered signal.

In an embodiment of the invention, the low pass filtering described above is an infinite impulse response filtering.

In an embodiment of the invention, the cross-correlation operation described above is a fast cross-correlation operation.

Based on the above, the embodiment of the present invention cross-correlates the sound signal received by the sound receiver with the preset sound signal to generate a cross-correlation signal, and corresponds to a time point of the preset sound signal and a cross-correlation signal according to the speaker output. Calculating a first distance and a second distance according to a first sound receiving time of the first peak and a second sound receiving time corresponding to the second peak, and calculating a distance between the sound receiver and the reflector according to the first distance and the second distance, It reduces the number of sound receivers required for distance measurement.

The above described features and advantages of the invention will be apparent from the following description.

102, 102'‧‧‧ Speakers

104‧‧‧Sound Receiver

106‧‧‧ Processor

A1‧‧‧reflector

d, R, R1, R2, H‧‧‧ distance

s(t)‧‧‧Preset sound signal

tA, tB, t_Tx, t_Max, t_Tx_IIR, t_Rx_IIR‧‧‧ time

T1‧‧‧ time difference

TA, TC, TN‧‧‧ length of time

Tx_IIR‧‧‧ first low pass filtered signal

Rx_IIR‧‧‧second low pass filtered signal

y(t)‧‧‧ sound signal

S402~S406‧‧‧ Distance detection device distance detection method steps

1 is a schematic diagram of a distance detecting device in accordance with an embodiment of the present invention.

2 is a waveform diagram of a cross-correlation signal in accordance with an embodiment of the present invention.

FIG. 3A is a waveform diagram of a preset sound signal output by a speaker according to an embodiment of the invention.

3B is a waveform diagram of a sound signal received by a sound receiver in accordance with an embodiment of the present invention.

4 is a flow chart of a distance detecting method of a distance detecting device according to an embodiment of the invention.

1 is a schematic diagram of a distance detecting device according to an embodiment of the present invention. Please refer to FIG. 1. The distance detecting device includes a speaker 102, a sound receiver 104, and a processor 106. The processor 106 is coupled to the sound receiver 104. The relative distance R1 between the speaker 102 and the sound receiver 104 can be fixed, for example. . The speaker 102 is disposed on one side of the reflector A1, the speaker 102 can output a preset sound signal, and the reflector A1 can reflect the preset sound signal to generate a reflected sound signal, wherein the preset sound signal has a time-varying amplitude and frequency, that is, It is said that the preset sound signals can correspond to different amplitudes and frequencies at different time points, and correspondingly, the reflected sound signals also have time-varying amplitudes and frequencies. The sound receiver 104 is configured to receive a sound signal, and the processor 106 can be used to receive the preset sound signal and the sound receiver 104. The sound signal is signal processed. The sound signal received by the sound receiver 104 may include a preset sound signal output by the speaker 102 and a reflected sound signal generated by the reflector A1 reflecting the preset sound signal, wherein the reflected sound signal may be equivalent to being centered on the reflector A1. As shown in FIG. 1, the speaker 102 and the virtual speaker 102' are symmetric with respect to the reflector A1, and are all spaced apart from the reflector A1 by a distance d.

The processor 106 can include, for example, a central processing unit or other programmable general purpose or special purpose microprocessor (Microprocessor), digital signal processor (DSP), controller, special application integrated circuit. (Application Specific Integrated Circuit, ASIC), Programmable Logic Device (PLD) or other similar device or a combination of these devices. In addition, the processor 106 may be configured with a volatile storage medium such as a random access memory (RAM) or a read-only memory (ROM). The processor 106 may be integrated with the sound receiver 104 on the same electronic device (for example, portable). In the electronic device, the sound receiver 104 is also disposed in a different electronic device. In some embodiments, the processor 106 can also transmit signals to the speaker 102 and the sound receiver 104 in a wired or wireless manner via a network or other means.

The processor 106 may perform a cross-correlation operation on the sound signal received by the sound receiver 104 and the preset sound signal output by the speaker to generate a cross-correlation signal, wherein the cross-correlation operation may be, for example, a fast cross-correlation operation, but This is limited. 2 is a waveform diagram of a cross-correlation signal in accordance with an embodiment of the present invention. As shown in FIG. 2, the sound signal received by the sound receiver 104 includes a preset sound signal output by the speaker 102 and a reflected sound signal generated by the reflector A1 reflecting the preset sound signal, so the cross-correlation signal will include a first peak corresponding to the preset sound signal and a second peak corresponding to the reflected sound signal, wherein The sound receiving time tA corresponding to the first peak and the second peak correspond to the sound receiving time tB. The processor 106 can calculate the distance R1 between the sound receiver 104 and the speaker 102 based on the sound receiving time tA, and calculate the distance R2 between the sound receiver 104 and the virtual speaker 102' in accordance with the sound receiving time tB. Thus, the processor 106 can calculate the distance between the sound receiver 104 and the reflector A1 according to the distance R1, the distance R2, and the distance between the speaker 102 and the virtual speaker 102', for example, the sound receiver 104 and the speaker 102 and the virtual speaker 102 are calculated. The distance R between the midpoints of ', or the distance H between the sound receiver 104 and the reflector A1 in the normal direction of the reflector A1. It can be seen from the above that the distance detecting device of the present embodiment can obtain the distance R or the distance H between the sound receiver 104 and the reflector A1 using only one sound receiver 104, and can use less sound than the prior art. The receiver can achieve the purpose of distance measurement.

In detail, the distance R1 between the sound receiver 104 and the speaker 102 and the distance R2 between the sound receiver 104 and the virtual speaker 102' can be obtained by the following equations: R 1 = c . ( tB - tA ) (1)

R 2 = c . ( tB-tA ) (2)

Where c is the speed of sound. Further, the distance R between the sound receiver 104 and the midpoint of the speaker 102 and the virtual speaker 102' and the distance H between the sound receiver 104 and the reflecting plate A1 can be obtained, for example, by the following equations, respectively:

The cross-correlation signal is generated by the cross-correlation operation between the sound signal received by the sound receiver 104 and the preset sound signal, and the sound receiving corresponding to the first peak in the cross-correlation signal is output according to the time point at which the speaker 102 outputs the preset sound signal. The time tA and the sound receiving time tB corresponding to the second peak calculate the distance R1 and the distance R2, and the distance between the sound receiver 104 and the reflecting plate A1 can be calculated according to the distance R1 and the distance R2, thereby effectively reducing the distance measurement required. The number of sound receivers.

In some embodiments, the processor 106 can perform data transmission with the speaker 102 by way of network transmission to know the time point at which the speaker 102 outputs the preset sound signal. The time difference between the first low-pass filtered signal and the preset sound signal obtained by the low-pass filtering of the preset sound signal (for example, the infinite impulse response filtering of the preset sound signal, but not limited thereto) The processor 106 can estimate the time corresponding to the peak of the packet amplitude of the preset sound signal received by the sound receiver 104 according to the time difference, and according to the peak amplitude of the packet amplitude of the preset sound signal received by the sound receiver 104. The distance R1 between the speaker 102 and the sound receiver 104 is calculated at the exact time and the time at which the speaker 102 outputs the peak amplitude of the packet of the preset sound signal. For example, FIG. 3A is a waveform diagram of a preset sound signal output by a speaker according to an embodiment of the invention. In FIG. 3A, the packet vibration of the preset sound signal s(t) The amplitude peak corresponds to the time t_Tx, and the amplitude peak of the first low-pass filtered signal Tx_IIR (shown by the dotted line) obtained by the low-pass filtering of the preset sound signal s(t) corresponds to the time t_Tx_IIR, and the first low-pass filtered signal The time difference t1 between Tx_IIR and the preset sound signal s(t) is equal to t_Tx_IIR-t_Tx.

The processor 106 can low-pass filter the sound signal received by the sound receiver 104 (for example, performing the same low-pass filtering process as the low-pass filtering performed by the preset sound signal) to generate a second low-pass filtered signal, and process The controller 106 predicts the second time corresponding to the peak of the packet amplitude of the preset sound signal received by the sound receiver 104 according to the time difference value and the second low-pass filtered signal. For example, FIG. 3B is a waveform diagram of a sound signal received by a sound receiver in accordance with an embodiment of the present invention. In FIG. 3B, the amplitude peak of the second low-pass filtered signal Rx_IIR (shown by a broken line) obtained by the low-pass filtering of the sound signal y(t) received by the sound receiver 104 corresponds to the time t_Rx_IIR, and the processor 106 The time difference t1 can be subtracted from the time t_Rx_IIR to estimate the time t_Max corresponding to when the sound receiver 104 receives the peak of the packet amplitude of the preset sound signal.

The processor 106 can determine whether the difference between the frequency value of the sound signal y(t) received by the sound receiver 104 corresponding to the time t_Max and the frequency value of the preset sound signal s(t) output by the speaker 102 corresponding to the time t_Tx is Exceeding the preset range. In detail, the processor 106 may perform the sound signal y(t) received by the sound receiver 104 within the time length T_C within a time length T_C based on the time t_Max (eg, centered on time t_Max, but not limited thereto). Fourier transform operation, and judge the time length T_C within the time base T_Tx (for example, centered on time t_Tx, but not limited to this) The sound signal y(t) received by the tone receiver 104 has a frequency value of a frequency domain signal having a maximum amplitude in the frequency domain and a frequency value of a preset sound signal s(t) output by the speaker 102 corresponding to the time t_Tx. Whether the difference is outside the preset range. The difference between the frequency value of the sound signal y(t) received by the sound receiver 104 corresponding to the time t_Max and the frequency value of the preset sound signal s(t) output by the speaker 102 corresponding to the time t_Tx does not exceed the preset range. At this time, the representative sound receiver 104 has received the preset sound signal s(t). The time length T_C can be set, for example, to a time length corresponding to the packet amplitude of the preset sound signal s(t) being less than the preset value, that is, only the portion with a larger amplitude of the packet in the preset sound signal s(t) is used. The comparison of the frequency values is to improve the accuracy of the comparison result, and also to reduce the amount of computation of the processor 106.

The difference between the frequency value of the sound signal y(t) received by the sound receiver 104 corresponding to the time t_Max and the frequency value of the preset sound signal s(t) output by the speaker 102 corresponding to the time t_Tx is not When the preset range is exceeded, the preset sound signal s(t) outputted by the speaker 102 in the time length T_C based on the time t_Tx and the sound receiver 104 received in the time length T_N based on the time t_Max are received. The sound signal is subjected to a cross-correlation operation to generate a cross-correlation signal, wherein the cross-correlation operation can be, for example, a fast cross-correlation operation, but not limited thereto. Further, the time length T_N is greater than the time length T_C, and the time length T_N can be set to, for example, greater than or equal to The time length TA of the sound signal s(t) is preset, but must be less than the time required for the predetermined sound signal s(t) to convey the farthest relative distance that the speaker 102 and the sound receiver 104 can be configured in the use space. The processor 106 can according to the time t_Rx corresponding to the amplitude peak of the cross-correlation signal (that is, the sound receiver 104 receives the preset sound). The exact time of the peak amplitude of the envelope of the tone signal s(t) can be calculated as the distance R1 between the speaker 102 and the sound receiver 104 as time tA) and time t_Tx of the embodiment of Fig. 1. For example, the distance R1 between the speaker 102 and the sound receiver 104 may be equal to (t_Rx - t_Tx) x c, where c is the speed of sound.

It should be noted that, in some embodiments, the time length T_N may also be set to be less than the time length TA. For example, the time length T_N is set to be smaller than another preset value corresponding to the preset sound signal s(t). length of time. Thus, by setting the time length T_N to be less than the time required for the predetermined sound signal s(t) to deliver the farthest relative distance that the speaker 102 and the sound receiver 104 can be configured in the usage space, the processor 106 does not need to be as conventional. The preset sound signal s(t) and the sound receiver 104 are configured to be configurable in the use space for a long time (at least the length of time TA plus the preset sound signal s(t) is transmitted in the space of use of the speaker 102 and the sound receiver 104. The received sound signal y(t) is subjected to a cross-correlation operation within the time required for the farthest relative distance, and the processor 106 can greatly reduce the preset sound signal s(t) and the sound signal y(t). The time to perform the cross-correlation operation. Moreover, since the processor 106 has first determined the frequency value and corresponding value of the frequency domain signal having the maximum amplitude in the frequency domain of the sound signal y(t) received by the sound receiver 104 within the time length T_C based on the time t_Tx The difference between the frequency values of the preset sound signals s(t) outputted by the speaker 102 of the time t_Tx does not exceed the preset range, so that it is also ensured that the sound receiver 104 has received the preset sound signal s(t), and thus The time t_Rx at which the sound receiver 104 receives the peak amplitude of the packet of the preset sound signal s(t) is accurately obtained, thereby calculating the distance R1 between the speaker 102 and the sound receiver 104.

By analogy, the distance between the virtual speaker 102' and the distance R2 between the sound receivers 104 can also be obtained in a similar manner. Those skilled in the art should be able to understand the embodiments thereof by the above embodiments, and therefore Let me repeat.

In some embodiments, the relative speed between the speaker 102 and the sound receiver 104 is not zero. The processor 106 can also use the Doppler effect to correct the calculated distance between the speaker 102 and the sound receiver 104. For example, the speaker 102 can output a preset sound signal, for example, every other time period. In this embodiment, the preset sound signal s(t) can be expressed by the following equation: s ( t )= A ( t ). Cos[2 π . f ( t ). t ] (5)

Where t is time, A(t) is the amplitude of the preset sound signal s(t), and f(t) is the frequency of the preset sound signal s(t). The length of time of each time period can be set, for example, to the length of time of the preset sound signal s(t) plus the preset sound signal s(t) to convey the farthest relative position that the speaker 102 and the sound receiver 104 can configure in the use space. The required time from the distance ensures that the sound receptor 104 can receive the preset sound signal s(t) emitted by the speaker 102 in each time period.

It is assumed that the speaker 102 outputs the preset sound signal s(t) in the mth period, where m is an integer greater than 1, and the preset sound signal s(t) corresponds to the peak of the packet amplitude of the preset sound signal s(t). t_Tx and frequency f_TMax, in addition, the preset sound signal y(t) received by the sound receiver 104 corresponds to the frequency f_TMax at time t_Max. The frequency f_RMax may be, for example, by the processor 106 for the sound signal y(t) received by the sound receiver 104 within a time length T_C based on the time t_Max (eg, centered on time t_Max, but not limited thereto). Fourier transform operation And ask for it. The frequency f_RMax can be, for example, the frequency value of the frequency domain signal having the maximum amplitude of the sound signal y(t) in the frequency domain, but is not limited thereto. In some embodiments, the processor 106 may further perform an interpolation operation (for example, a polynomial internal difference operation, but not limited thereto) according to the multiple frequency domain signals obtained after performing the Fourier transform operation, to obtain a more accurate method. Frequency f_RMax. The time length T_C can be set, for example, to a time length corresponding to the packet amplitude of the preset sound signal s(t) being less than the preset value, by using only the portion of the preset sound signal s(t) that has a larger amplitude. The comparison of values can increase the accuracy of the calculation frequency while reducing the amount of computation of the processor 106.

The processor 106 can correct the frequency value of the preset sound signal s(t) by using the Doppler effect according to the relative speed between the speaker 102 and the sound receiver 104 calculated last time. For example, the processor 106 is, for example, Sub-correction of the frequency f(t) of the preset sound signal s(t):

Where f'(t) is the corrected frequency, The initial relative velocity between the speaker 102 and the sound receiver 104 of the kthth step of the mth time period, c is the speed of sound, and k is a positive integer. The corrected preset sound signal x(t) can be as shown in the following equation:

The initial relative speed between the speaker 102 and the sound receiver 104 (relative speed when k is equal to 1) may be based on the frequency f_RMax and the frequency f_TMax by the processor 106. Calculated, for example, can be calculated according to the following formula.

among them The initial relative speed between the speaker 102 and the sound receiver 104 for the mth time period. The processor 106 may cross-correlate the corrected preset sound signal x(t) with the sound signal y(t) received by the sound receiver 104 to generate a cross-correlation signal, wherein the cross-correlation operation may be, for example, fast Cross-correlation operations are not limited to this. The processor 106 calculates the distance R1 between the speaker 102 and the sound receiver 104 according to the time t_Tx corresponding to the peak of the packet amplitude of the preset sound signal s(t) according to the time corresponding to the peak amplitude of the packet of the cross-correlation signal.

For example, the corrected relative distance of the kth order of the mth time period Can be as shown in the following formula:

The processor 106 may calculate the corresponding mth time period according to the corrected relative distance between the speaker 102 and the sound receiver 104 corresponding to the mth time period and the corrected relative distance between the speaker 102 and the sound receiver 104 corresponding to the m-1th time period. The relative speed between the speaker 102 and the sound receiver 104. For example, the relative speed of the kth order of the mth time period Can be as shown in the following formula:

Where Td is the length of time of each time period, and R _m-1 is the relative distance calculated by the m-1th time period. The processor 106 can get the initial relative speed Thereafter, the relative speed between the speaker 102 and the sound receiver 104 is calculated recursively according to the above equations (6), (7), (9), and (10) until the relative speed converges to a specific value. For example, the processor 106 may determine the corresponding mth according to the relative speed between the speaker 102 and the sound receiver 104 corresponding to the mth time period and the relative speed between the speaker 102 and the sound receiver 104 corresponding to the m-1th time period. Whether the relative speed between the speaker 102 and the sound receiver 104 has converge to a preset range. For example, the processor 106 can determine whether the relative speed has converged according to the following formula:

Where THV is the preset threshold, when The corrected relative distance of the kth order representing the mth period calculated by the processor 106 when the absolute value converges to a preset range of -THV and THV The accuracy has been met, and it can be used as the mth time period to determine the relative distance. Similarly, the relative speed of the kth order of the mth time period It can also be used as the final determination of the relative speed of the mth time period. Further, the final determined relative acceleration a _m between the speaker 102 and the sound receiver 104 of the mth time period can be expressed as follows: a _m = ( v _m - v _{m -1} ) / Td (12)

By analogy, the final determined relative distance between the virtual speaker 102' and the sound receiver 104 of the mth time period, the final determination of the relative speed, and the final determination of the relative acceleration may also be obtained in a similar manner, and those skilled in the art should be able to borrow The embodiments are known from the above embodiments, and therefore will not be described again.

4 is a flow chart of a method for detecting a distance of a distance detecting device according to an embodiment of the present invention. Please refer to FIG. 3. In this embodiment, the speaker is disposed on the reflector On one side, and the speaker and the virtual speaker are symmetric with respect to the reflector, the speaker can output a preset sound signal, and the reflector can reflect the preset sound signal to generate a reflected sound signal. The preset sound signal output by the speaker has a time-varying amplitude and frequency, and correspondingly, the reflected sound signal also has a time-varying amplitude and frequency. It can be seen from the above embodiments that the distance detecting method of the distance detecting device can include at least the following steps. First, the sound signal received by the sound receiver is cross-correlated with the preset sound signal to generate a cross-correlation signal, wherein the cross-correlation signal includes a first peak corresponding to the preset sound signal and a second corresponding to the reflected sound signal. The peak correlation (step S402), the cross-correlation operation may be, for example, a fast cross-correlation operation, but not limited thereto. Then, calculating a first distance and a second distance according to a time point at which the speaker outputs the preset sound signal, a first sound receiving time corresponding to the first peak, and a second sound receiving time corresponding to the second peak (step S404), wherein the first The distance is the distance between the sound receiver and the speaker, and the second distance is the distance between the sound receiver and the virtual speaker, and the speaker and the virtual speaker are separated by a third distance. Then, calculating the distance between the sound receiver and the reflector according to the first distance and the second distance (step S406), for example, calculating the normal of the sound receiver on the reflector according to the first distance, the second distance, and the third distance The distance between the direction and the reflector.

The time difference value between the first low-pass filtered signal obtained by the low-pass filtering of the preset sound signal and the preset sound signal may be, for example, the peak amplitude of the packet amplitude of the preset sound signal output by the speaker. The time difference between the time and the peak amplitude of the packet of the first low pass filtered signal. In some embodiments, the sound signal received by the sound receiver can be low pass filtered to generate a second low pass. Filtering the signal, and estimating the time when the sound receiver receives the preset sound signal and the reflected sound signal according to the time difference value and the second low-pass filter signal, to output the time and sound of the peak amplitude of the preset sound signal according to the speaker The time when the receiver receives the preset sound signal and the reflected sound signal calculates the distance between the sound receiver and the reflector.

In summary, the embodiment of the present invention cross-correlates the sound signal received by the sound receiver with the preset sound signal to generate a cross-correlation signal, and outputs a time point and a cross-correlation signal of the preset sound signal according to the speaker. Calculating a first distance and a second distance according to a first sound receiving time corresponding to the first peak and a second sound receiving time corresponding to the second peak, and calculating a distance between the sound receiver and the reflector according to the first distance and the second distance This reduces the number of sound receivers required for distance measurement.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and any one of ordinary skill in the art can make some changes and refinements without departing from the spirit and scope of the present invention. The scope of the invention is defined by the scope of the appended claims.

Claims (10)

A distance detecting device includes: a speaker disposed on one side of a reflector, and outputting a preset sound signal, the reflector reflecting the preset sound signal to generate a reflected sound signal; a sound receiver; and a The processor performs a cross-correlation operation on the sound signal received by the sound receiver with the preset sound signal to generate a cross-correlation signal, wherein the cross-correlation signal includes a first peak corresponding to the preset sound signal and Corresponding to a second peak of the reflected sound signal, the processor according to the time point of the speaker outputting the preset sound signal, a first sound receiving time corresponding to the first peak, and a second sound corresponding to the second peak The receiving time calculates a first distance and a second distance, wherein the first distance is a distance between the sound receiver and the speaker, and the second distance is a distance between the sound receiver and a virtual speaker, the speaker and the speaker The virtual speaker is symmetrical with respect to the reflector, and the speaker is separated from the virtual speaker by a third distance, the processor Calculating a distance between the sound receiver and the reflector in a normal direction of the reflector according to the first distance, the second distance, and the third distance, wherein the sound receiver and the speaker and the virtual speaker The distance between the midpoints and the distance between the sound receiver and the reflector are obtained by the following equations: ;as well as Where R1 is the first distance, R2 is the second distance, 2d is the third distance, R is the distance between the sound receiver and the midpoint of the speaker and the virtual speaker, and H is the sound receiver and The distance between the reflectors. The distance detecting device of claim 1, wherein the preset sound signal has a time-varying amplitude and frequency, and the first low-pass filtered signal obtained by the low-pass filtering of the preset sound signal Having a time difference with the preset sound signal, the processor performs the low pass filtering on the sound signal received by the sound receiver to generate a second low pass filtered signal, and the processor will correspond to The first time of the amplitude peak of the second low pass filtered signal is subtracted from the time difference to estimate the time when the sound receiver receives the preset sound signal and the reflected sound signal. The distance detecting device of claim 2, wherein the time difference is a time when the speaker outputs a peak amplitude of the packet amplitude of the preset sound signal and a peak of a packet amplitude of the first low-pass filtered signal. Time difference. The distance detecting device of claim 2, wherein the low pass filtering is an infinite impulse response filtering. The distance detecting device of claim 1, wherein the cross-correlation operation is a fast cross-correlation operation. A method for detecting a distance of a distance detecting device, the distance detecting device comprising a speaker and a sound receiver, the speaker being disposed on one side of a reflector for outputting a predetermined sound signal, the reflector reflecting the Predetermining the sound signal to generate a reflected sound signal, the distance detecting method of the distance detecting device comprises: cross-correlating the sound signal received by the sound receiver with the preset sound signal to generate a cross correlation a signal, wherein the cross-correlation signal includes a first peak corresponding to the preset sound signal and a second peak corresponding to the reflected sound signal; and a time point corresponding to the preset sound signal output by the speaker, corresponding to the first peak Calculating a first distance and a second distance corresponding to a first sound receiving time and a second sound receiving time corresponding to the second peak, wherein the first distance is a distance between the sound receiver and the speaker, the first The second distance is the distance between the sound receiver and a virtual speaker, and the speaker and the virtual speaker are opposite to the reflector Symmetrically, the speaker and the virtual speaker are separated by a third distance, and the distance detecting method of the distance detecting device comprises: calculating the sound receiver according to the first distance, the second distance, and the third distance a distance between the sound receiver and a midpoint of the sound speaker and a distance between the sound receiver and the reflector, respectively, obtained by the following equation : ;as well as Where R1 is the first distance, R2 is the second distance, 2d is the third distance, R is the distance between the sound receiver and the midpoint of the speaker and the virtual speaker, and H is the sound receiver and The distance between the reflectors. The distance detecting method of the distance detecting device according to claim 6, wherein the preset sound signal has a time-varying amplitude and frequency, and the preset sound signal is obtained by a low-pass filtering. A low-pass filtered signal and the preset sound signal have a time difference, and the distance detecting method of the distance detecting device comprises: performing low-pass filtering on the sound signal received by the sound receiver to generate a a second low pass filtered signal; and subtracting the time difference from a first time corresponding to an amplitude peak of the second low pass filtered signal to estimate that the sound receiver receives the preset sound signal and the reflected sound The time when the signal is. The distance detecting method of the distance detecting device according to claim 7, wherein the time difference is a time when the speaker outputs a peak amplitude of the packet of the preset sound signal and a packet of the first low-pass filtered signal. The time difference corresponding to the amplitude peak. The distance detecting method of the distance detecting device according to claim 7, wherein the low pass filtering is an infinite impulse response filtering. The distance detecting method of the distance detecting device according to claim 6, wherein the cross-correlation operation is a fast cross-correlation operation.