JP2007328133A - Delay time detection apparatus, method and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a delay time detection apparatus capable of suppressing the erroneous detection of delay time is suppressed and also enhancing fast-responsiveness compatibly, and to provide a method and a program therefor. <P>SOLUTION: A change determination means 86 determines that the delay time is changed, when a correlation value R of a setup value Rt or more, which is preset in a correlation means 83, is detected at a plurality of times for the same delay time Td, after the delay time Td is calculated at first in a calculation means 85. Preferably, when the correlation value R of the setting value Rt or more is detected at the plurality of times (for example, two times) for the same delay time Td or within a predetermined allowable error range Td±α, within predetermined measurement cycles, it is determined that the delay time is changed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to suppression of erroneous detection in delay time detection.

  When relaying satellites, the broadcast radio signal delayed from the actual sound is removed from the announcer's monitor earphone to make it easier to talk, etc., and the other delay time is detected based on one audio signal. A delay time detecting device is used. As an operation of the delay time detection device, after the delay time is first detected, a change in the delay time is detected as needed.

  In the delay time detection apparatus by the present applicant, as shown in FIG. 1 of Patent Document 1, a certain length is sampled and extracted from the reference first audio signal, and from the delayed second audio signal, A long range is sampled and extracted, and the correlation value is detected by the correlation means 83 while shifting the two samples.

Then, when this correlation value exceeds a predetermined set value for the first time, as the first detection of the delay time, the delay time according to the deviation at that time is calculated, and the change in the delay time thereafter As is the case up to the first time, assuming that the correlation value calculated from time to time exceeds the correlation value obtained the first time, the delay time has changed, and a new delay time is recalculated from the new deviation at that time. It was.
JP 2000-307486 A

  However, the conventional technology as described above has a problem that erroneous detection is likely to occur because the correlation value is treated as a change in delay time when the correlation value exceeds the initial correlation value even once. That is, when the correlation value obtained first is not less than the set value but is a relatively low value, such as when a music signal such as BGM is mixed with the second audio signal, the correlation value is thereafter set. By simply detecting that the delay time has changed each time a correlation value exceeding the value is detected, erroneous detection is likely to occur, and the determined delay time and device operation based on it are unstable. There are problems such as a factor, and an operator is forced to perform re-detection setting of the apparatus when erroneous detection occurs, causing a load to monitor the device.

  The present invention solves the problems of the prior art as described above, and its object is to suppress erroneous detection of delay time. Another object of the present invention is to achieve both responsiveness in addition to suppression of false detection.

  Based on the above object, one aspect of the delay time detecting apparatus according to the present invention includes a first holding unit that holds a first audio signal having a first number of samples, and a second that delays the first audio signal. Second holding means for holding a second audio signal having a second sample number larger than the first sample number, and the first and second audio signals having the first sample number. Correlation means for sequentially calculating a correlation value of a signal by shifting one sample at a time for the second audio signal held in the second holding means; and a correlation value equal to or greater than a preset set value by the correlation means When calculated, a calculation unit that calculates a delay time of the second audio signal based on the number of samples shifted until the correlation value is calculated, and the delay time is first calculated by the calculation unit Later, preset by the correlation means More than the set value of the correlation value a predetermined plurality of times, when it is detected for the same delay time, characterized by having a a change determining means for determining that the delay time is changed.

  In this way, it is determined that a correlation value equal to or greater than the set value has been detected a predetermined number of times for the same delay time, and by treating that the correlation value has changed to that delay time, erroneous detection due to a low initial correlation value is effective. Can be suppressed.

  According to another aspect of the present invention, the change determination unit further includes the delay determination unit when the correlation unit detects a correlation value greater than or equal to the set value for a plurality of times within a predetermined number of measurements for the same delay time. It is judged that time has changed.

  In this way, the detection of the change in the delay time is recognized if the same delay time is detected within a predetermined number of measurements, not limited to the continuous measurement, so that the change can be detected quickly, and both the quick response can be achieved.

  In another aspect of the present invention, the change determination unit further records the correlation value and the delay time in the ring buffer for the latest predetermined number of measurements, and performs the plurality of times for the same delay time by collating with the contents. It is characterized by making a judgment.

  As described above, by the collation process using the ring buffer, it is possible to reliably execute an appropriate delay time change determination using a finite memory resource and a simple algorithm.

  According to another aspect of the present invention, the change determination means sets the previous delay time for the correlation value detected by the correlation means only before the determination that the change is detected a plurality of times is first made. Alternatively, when the correlation value is higher than that when it is determined to be a change, it is determined that the delay time has changed.

  In this way, by combining with the determination that the delay time has changed even once, if a higher correlation value is detected than when it was determined that the change in the delay time was detected before multiple detections, the first time By avoiding the negative effects of the prior art based on the correlation value, it is possible to implement a quick response and a reliable process.

  As described above, according to the present invention, it is determined that a correlation value equal to or greater than a set value has been detected for the same delay time a predetermined number of times, and by treating that the correlation value has changed to that delay time, False detection due to lowness can be effectively suppressed.

  Next, the best mode for carrying out the present invention will be described with reference to the drawings. Note that assumptions common to the explanation in the background art and problems are omitted as appropriate. First, the delay time detection apparatus (hereinafter referred to as “the present apparatus”) of the present embodiment has each means 71, 72, 81 to 86 shown in the configuration diagram of FIG. 1 and operates as follows.

  That is, the first holding means 81 holds the first audio signal S71 of the first sample number N1 that is converted from the reference audio signal by the A / D conversion means 71 and cut out therefrom. The audio signal to be subjected to delay detection is digitally converted by the A / D conversion means 72, and the second holding means 82 holds the second audio signal S72 (audio delay signal) cut out therefrom. The second audio signal S72 is a delayed version of the first audio signal S71 and has a second sample number N2 that is larger than the first sample number N1 of the first audio signal S71. These digital conversion and cut-out control are performed by an appropriate electronic circuit or an arithmetic control unit of a computer such as a CPU.

  Further, the correlation means 83 holds the correlation value R of the first and second audio signals S71 and S72 of the first sample number N1 held as described above in the second holding means 82. The second audio signal S72 is sequentially calculated by shifting by one sample. Then, when the correlation value R equal to or greater than the preset set value Rt is calculated by the correlation unit 83, the calculation unit 85 calculates the second value based on the sample number A shifted until the correlation value R is calculated. The delay time Td of the audio signal S72 is calculated.

  Further, the change determining means 86 calculates the delay time Td for the first time by the calculating means 85, and then sets the correlation value R equal to or greater than the preset value Rt preset by the correlation means 83 a predetermined number of times and the same delay time Td. Is detected, the delay time is determined to have changed. Note that the comparison means 84 compares whether the correlation value R is greater than or equal to the set value Rt.

  Thus, in this embodiment, it is determined that the correlation value R equal to or greater than the set value Rt has been detected for the same delay time Td a plurality of times, and the first correlation is handled by treating that the correlation value R has changed to the delay time Td. False detection due to low value can be effectively suppressed.

  In addition, the change determination unit 86 is not limited to the correlation value R that is equal to or greater than the set value Rt by the correlation unit 83, and is not limited to a plurality of times (for example, twice) within a predetermined number of times, for the same delay time Td or for a predetermined time It is desirable to configure so that the delay time is determined to be changed when detection is made for the allowable error range Td ± α.

  Here, FIGS. 2 and 3 are flowcharts for determining a change in delay time after the first detection. FIG. 4 shows a state in which the detected (calculated) delay time and correlation value are retained in the ring buffer from the top to the bottom, and the hatched portion retains the portion before the latest five times. Indicates unnecessary.

  Each unit record in the ring buffer is shown in a column such as the number of detections “1”, “2”... In FIG. 4, and in addition to the detected delay time (detection time) and the correlation value, It has a holding number indicating whether or not the detection is the first time, and a set delay time which is a delay time currently recognized by the present apparatus.

  Further, the maximum number of times “1” or “2” appearing in the record in the ring buffer is recorded in a predetermined counter and called “counter value”. FIG. 2 shows that any counter value in the ring buffer is still “1”. ”Shows a processing procedure while the counter value is“ 1 ”, and FIG. 3 shows a processing procedure after the counter value becomes“ 2 ”. As the counter value, the maximum value of the number of holding times in the ring buffer is written, but once it becomes “2”, it remains “2” until it is reset.

  In the example of FIG. 4, the latest five records are stored in the ring buffer, and it is determined whether the same detection time has been detected multiple times by collating the contents with the latest detection result. The number of records held above is free.

  While the counter value is “1”, as shown in FIG. 2, when the calculated correlation value R is equal to or higher than the set value Rt (step S01), which is the lower limit threshold (step S02), it is detected in the ring buffer. It is determined whether or not there are records having the same time (step S03), the counter value is set to “2” (step S04), and the set delay time is changed according to the detection time detected this time (step S05). The current detection result (detection time, correlation value) is recorded as a record in the ring buffer as the holding count “2” (step S06), and the process proceeds to the flowchart of FIG.

  On the other hand, if there is no record with the same detection time in the ring buffer for a correlation value greater than or equal to the set value (step S03), if the current correlation value is higher than when the detection time was changed last time (step S07), the current detection time To change the delay time (step S08). Thereafter, the number of times of holding is set to 1 (step S09). If the number of times of detection is 6th or more (step S10), the latest 5 records including the current value are held in the ring buffer (step S11), and the number of times of detection is 5th. Up to (step S10), the current value is added as a record to the ring buffer and held (step S12).

  When the counter value is “2” (FIG. 3), when the detected correlation value is (step S21) equal to or greater than the set value (step S22) and there is no record with the same detection time (step S23), the current number of holdings is set. Once (step S24). On the other hand, if there are records with the same detection time (step S23) and the number of holding times is one (step S25), the delay time is changed with the current detection time (step S26). Thereafter, including the case where the record having the same detection time (step S23) has already been held twice (step S25), the current hold count is set to 2 (step S27). In either case, up to five records are held in the ring buffer according to the number of detections including this time (step S28) (steps S29 and S30).

  With the above processing, in the example of FIG. 4, the detection time 1.22 seconds for the second detection count is reflected in the set delay time because the correlation value is 0.7 and higher than 0.65 for the first time. . In addition, from the seventh detection count when the counter value is 2, if the same delay time is detected twice or more with a correlation value greater than or equal to the set value, it is recognized that the delay time has changed. The time 1.33 seconds is reflected in the set delay time as the second holding count, while the detection time 1.89 seconds at the ninth detection count is not reflected in the set delay time because it is the first holding count.

  As described above, it is determined that a correlation value equal to or greater than the set value has been detected for the same delay time a predetermined number of times, and it is treated as having changed to that delay time. It can be effectively suppressed. More specifically, in the present embodiment, it is determined that the delay time has not been changed until the same time is detected twice from a certain number of measurements, and the delay value provided to the outside, that is, the set delay time is left as it is. If the state is held and the same time is detected twice from a certain number of measurements, it is recognized that the delay time has changed, and the actual delay value is changed.

  In particular, with respect to a correlation value that is equal to or greater than a predetermined value with the same delay time, there is a demerit that it takes a long time to recognize the change and the quick response is impaired in a plurality of detections. Therefore, if the detection is performed multiple times with the same delay time even if it is not continuous, the detection accuracy of the delay time is improved by treating it as a change in the delay time, and the change in the delay time can be detected without requiring a long time. As a result, the operator is less likely to perform re-detection setting when an error is detected, and the load for monitoring the device is reduced.

  Furthermore, in the present embodiment, it is possible to reliably execute an appropriate change in delay time by using a finite memory resource and a simple algorithm by performing a matching process using a ring buffer.

  In addition, in this embodiment, before a plurality of times of detection, if a higher correlation value is detected than when it was determined that the previous delay time has changed, it may be determined that the delay time has changed even once. By combining them, it is possible to avoid the adverse effects of the prior art based on the first correlation value, and to realize a quick response and a reliable process.

  The present invention is not limited to the above-described embodiment. For example, the number of times for repeatedly detecting the same detection time and allowing the delay time change is not limited to two, and may be three or more. When the counter value is once, the process of recognizing the change in the delay time is not essential when the correlation value is higher than when the previous delay time was set or changed. Further, in the above example, the correlation value is not retained when it is equal to or lower than the lower limit threshold, but may be retained.

The figure which shows the structure of embodiment of this invention. The flowchart (counter value 1) which shows the process sequence in embodiment of this invention. The flowchart (counter value 2) which shows the process sequence in embodiment of this invention. The figure which shows the content of the ring buffer in embodiment of this invention.

Explanation of symbols

71, 72 ... A / D conversion circuits 81, 82 ... holding means 83 ... correlation means 84 ... comparison means 85 ... calculation means 86 ... change judgment means

Claims (12)

First holding means for holding a first audio signal of a first number of samples;
Second holding means for holding a second audio signal having a second number of samples larger than the first number of samples, the second audio signal being delayed by the first audio signal;
Correlation means for sequentially calculating the correlation value of the first and second audio signals of the first number of samples by shifting one sample at a time for the second audio signal held in the second holding means;
Calculation that calculates the delay time of the second audio signal based on the number of samples shifted until the correlation value is calculated when a correlation value that is equal to or greater than a preset setting value is calculated by the correlation means Means,
After the delay time is first calculated by the calculating means, the delay time changes when a correlation value equal to or higher than a preset value preset by the correlation means is detected for the same delay time a plurality of times. Change judging means for judging,
A delay time detection apparatus comprising:   The change determining means determines that the delay time has changed when a correlation value equal to or greater than the set value is detected for the same delay time a plurality of times within a predetermined number of measurements. The delay time detecting apparatus according to claim 1, wherein:   The change determining means records the correlation value and delay time for the latest predetermined number of measurements in a ring buffer, and makes the determination for the same delay time a plurality of times by collating with the contents. Item 3. The delay time detecting device according to Item 2.   The change determination means is based on the correlation value when the correlation value detected by the correlation means is set to the previous delay time or is determined to be changed only before the determination that the detection is made a plurality of times is first performed. The delay time detection apparatus according to claim 1, wherein when it is high, it is determined that the delay time has changed. In a delay time detecting method for detecting a delay time of an audio signal, an electronic control circuit or an arithmetic control unit of a computer uses a first holding unit, a second holding unit, a correlating unit, a calculating unit, and a change determining unit. And realizing
Holding a first audio signal of a first number of samples with the first holding means;
Holding the second audio signal, which is a delayed second audio signal, the second sample number being larger than the first sample number, by the second holding means;
The correlation means sequentially calculates the correlation values of the first and second audio signals of the first number of samples by shifting one sample at a time for the second audio signal held in the second holding means. Steps,
When a correlation value equal to or greater than a preset set value is calculated by the correlation unit, the delay of the second audio signal based on the number of samples shifted by the calculation unit until the correlation value is calculated Calculating a time;
After the delay time is first calculated by the calculation means by the change determination means, and when a correlation value equal to or higher than a preset value set in advance by the correlation means is detected for the same delay time a plurality of times, Determining that the delay time has changed;
A delay time detection method comprising:   The change determining means determines that the delay time has changed when a correlation value equal to or greater than the set value is detected by the correlation means a plurality of times within a predetermined number of measurements for the same delay time. The delay time detecting method according to claim 5. By the change judging means,
Recording the correlation value and delay time in a ring buffer for the latest predetermined number of measurements;
Performing the plurality of determinations for the same delay time by collating with the contents of the ring buffer;
The delay time detecting method according to claim 6, wherein:   The correlation value detected by the correlation unit is set to the previous delay time or from the correlation value when it is determined to be changed only before the change determination unit first determines that the detection is made a plurality of times. 8. The delay time detection method according to claim 5, further comprising a step of determining that the delay time has changed when the delay time is high. In a delay time detection program for detecting a delay time of an audio signal, a first holding means, a second holding means, a correlating means, a calculating means, and a change judging means are controlled by controlling an arithmetic control unit of a computer. And realizing
Holding the first audio signal of the first number of samples by the first holding means;
A second audio signal in which the first audio signal is delayed, and a second audio signal having a second sample number larger than the first sample number is held by the second holding unit;
The correlation means sequentially calculates the correlation values of the first and second audio signals of the first number of samples by shifting one sample at a time for the second audio signal held in the second holding means. ,
When a correlation value equal to or greater than a preset set value is calculated by the correlation unit, the delay of the second audio signal based on the number of samples shifted by the calculation unit until the correlation value is calculated Let the time be calculated,
After the delay time is first calculated by the calculation means by the change determination means, and when a correlation value equal to or higher than a preset value set in advance by the correlation means is detected for the same delay time a plurality of times, A delay time detection program for determining that the delay time has changed.   The change determining means causes the correlation means to determine that the delay time has changed when a correlation value equal to or greater than the set value is detected for the same delay time a plurality of times within a predetermined number of measurements. The delay time detection program according to claim 9.   The change determination means causes the correlation value and delay time to be recorded in a ring buffer for the latest predetermined number of measurements, and to make a plurality of determinations for the same delay time by collating with the contents of the ring buffer. 11. The delay time detection program according to claim 10, wherein   The correlation value detected by the correlation unit is set to the previous delay time or from the correlation value when it is determined to be changed only before the change determination unit first determines that the detection is made a plurality of times. The delay time detection program according to any one of claims 9 to 11, wherein when it is high, the delay time is determined to have changed.

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