JP4900329B2 - Signal detection apparatus and signal detection program - Google Patents

Description

  The present invention relates to a signal detection device and a signal detection program.

  With the development of technologies such as printers and copiers, it has become possible to easily create and duplicate documents, and documents have been used in various situations.

  On the other hand, since the document can be easily copied, new problems such as maintaining the confidentiality of the document and guaranteeing the originality have arisen.

  In order to deal with such problems, a magnetic material is attached to the paper, and the magnetic material is detected by a detection device arranged in a printer, copier, gate, etc., and the result is used for various managements. Yes.

As a technique for processing the output of the sensor using a CPU, for example, there is one described in Patent Document 1.
Japanese Patent Laid-Open No. 61-181988

  An object of the present invention is to provide a signal detection device and a signal detection program for accurately detecting a signal generated by the large Barkhausen effect by positioning a magnetic body in an alternating magnetic field.

In order to achieve the above-mentioned object, the invention of claim 1 is characterized in that a detection signal at a specific time among detection signals output from a detection means including a signal reception means and an amplification means for amplifying the signal received by the signal reception means. obtaining means for obtaining, calculates the average value of the detection signal obtained by the obtaining unit, comparing means averages the calculated is compared to or greater than the reference value, before Symbol detection signal is equal to or greater than the reference value A determination means for determining that the detection signal includes a signal generated by a large Barkhausen effect when it is confirmed that the comparison result by the comparison means is a predetermined number of times, and the amplification of the amplification means An adjusting means for adjusting the degree of adjustment, and the adjusting means fixes the amplification degree by the adjusting means in the absence of a signal caused by a large Barkhausen effect, and the reference value and the comparing means obtain the average value. Each value when the determination means includes the signal generated by the large Barkhausen effect is predetermined, and the average number of times of output and the number of times the determination means confirms continuity are varied. And a setting means for setting a new reference value, an average number of times, and a number of times of confirming continuity, respectively .

  According to a second aspect of the present invention, in the first aspect of the invention, the determination means determines that the detection signal acquired by the acquisition means includes a signal generated by the large Barkhausen effect, and then the detection signal is a reference. When it is confirmed that comparison results less than the value continue for a predetermined number of times, it is determined that the signal generated by the large Barkhausen effect has disappeared from the detection signal.

According to a third aspect of the present invention, in the first or second aspect of the invention, the setting means calculates the reference value and the comparison means calculate the average value in the absence of a signal caused by a large Barkhausen effect. The average number of times and the number of times the determination means confirms continuity are fixed, the amplification means is varied by the adjustment means, and the determination means generates a signal generated by the large Barkhausen effect in the detection signal. A value obtained by subtracting a predetermined value from the degree of amplification when it is determined that the signal contains is set as a new degree of amplification .

Further, the invention of claim 4 is an acquisition process for acquiring a detection signal at a specific time among detection signals output by a detection means including a signal reception means and an amplification means for amplifying the signal received by the signal reception means; By the comparison process of calculating an average value of the detection signals acquired in the acquisition process and comparing whether or not the calculated average value is a reference value or more, and the comparison process that the detection signal is a reference value or more A determination process for determining that the detection signal includes a signal generated by a large Barkhausen effect when it is confirmed that the comparison result continues for a predetermined number of times, and an adjustment process for adjusting the amplification degree of the amplification means; , The amplification degree of the amplification means is fixed by the adjustment process in the absence of a signal caused by the large Barkhausen effect, the reference value, the average number of times when the average value is calculated by the comparison process, Each value of the number of times of confirming continuity in the determination process is variable, and a value obtained by adding a predetermined value to each value when the determination process determines that the detection signal includes a signal generated by a large Barkhausen effect. The computer is caused to execute a new reference value, an average number of times, and a setting process for setting the number of times to confirm continuity .

According to a fifth aspect of the present invention, in the fourth aspect of the present invention, after the determination process determines that the detection signal acquired in the acquisition process includes a signal generated by a large Barkhausen effect, the detection signal is a reference. When it is confirmed that comparison results less than the value continue for a predetermined number of times, it is determined that the signal generated by the large Barkhausen effect has disappeared from the detection signal .

According to a sixth aspect of the present invention, in the fourth or fifth aspect of the present invention, the setting process is performed when the reference value and the comparison means calculate the average value in the absence of a signal generated by a large Barkhausen effect. Each of the average number of times and the number of times the continuity is confirmed in the determination process are fixed, the amplification degree of the amplification means is varied by the adjustment process, and the determination process is a signal generated by the large Barkhausen effect in the detection signal. A value obtained by subtracting a predetermined value from the degree of amplification when it is determined that the signal contains is set as a new degree of amplification .

  According to the present invention, it is possible to accurately detect a signal generated by the large Barkhausen effect even in a state where noise or the like is mixed.

  Hereinafter, an embodiment of a signal detection device and a signal detection program according to the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a block diagram illustrating a configuration example of a signal detection device. As shown in the figure, the signal detection apparatus includes a signal source 1, an excitation coil 2, a detection coil 3, a filter 4, an amplifier 5, a filter 6, an ADC 7, and a signal determination unit 8.

  The signal source 1 is a power source for causing an alternating current to flow through the exciting coil 2. For example, an alternating voltage of 1 kHz is applied to the exciting coil 2 to generate an alternating magnetic field in the exciting coil 2.

  The exciting coil 2 is one in which an alternating current flows according to the alternating voltage applied from the signal source 1, and thereby generates an alternating magnetic field.

  In the detection coil 3, an alternating current flows due to an electromotive force induced by an alternating magnetic field generated by the exciting coil 2. At this time, a magnetic material that generates a large Barkhausen effect in the alternating magnetic field generated by the exciting coil 2 is provided. If there is, the pulse current due to the large Barkhausen effect is generated in a form superimposed on the alternating current. The detection coil 3 outputs this current as a detection current.

  The filter 4 removes the current induced by the alternating magnetic field generated by the excitation coil 2 from the detection current output by the detection coil 3.

  The amplifier 5 amplifies the detection current output from the filter 4.

  The filter 6 removes noise and the like from the detection current amplified by the amplifier 5.

  The ADC 7 is an AD converter, which converts a detection current into a digital signal and outputs it as a detection signal. To do.

  Based on the detection signal output from the ADC 7, the signal determination unit 8 determines whether the large Barkhausen effect has occurred, that is, whether there is a magnetic substance in the vicinity of the detection coil 3. The signal determination unit 8 also performs processing such as adjustment of the amplification degree (gain) of the amplifier 5.

  Next, details of the signal determination unit 8 will be described. FIG. 2 is a diagram illustrating a configuration example of the signal determination unit 8, and FIG. 3 is a block diagram illustrating a functional configuration example of the signal determination unit 8.

  As illustrated in FIG. 2, the signal determination unit 8 includes a calculation unit 101, a storage unit 102, a temporary storage unit 103, and an information input / output unit 104.

  The arithmetic unit 101 performs arithmetic processing, and is realized by a processor such as a CPU (Central Processing Unit), for example.

  The storage unit 102 stores information and the like, and is realized by a memory such as a ROM (Read Only Memory) and a nonvolatile memory (Nonvolatile Memory), for example.

  The temporary storage unit 103 temporarily stores information and the like, and is realized by a memory such as a RAM (Random Access Memory), for example.

  The information input / output unit 104 is an interface that inputs a detection signal from the ADC 7 and a reference signal from the signal source 1 and outputs a determination result and the like.

  The signal determination unit 8 operates the calculation unit 101 based on the program stored in the storage unit 102, and the other units operate according to instructions from the calculation unit 101, thereby realizing the functional units illustrated in FIG. .

  As shown in FIG. 3, the signal determination unit 8 includes a reference signal acquisition unit 81, a detection signal acquisition unit 82, an averaging unit 83, a comparison unit 84, a continuity determination unit 85, and an adjustment unit 86. is doing.

  The reference signal acquisition unit 81 acquires a signal synchronized with the AC voltage applied from the signal source 1 to the excitation coil 1 as a reference signal.

  The detection signal acquisition unit 82 acquires the detection signal output by the ADC based on the reference signal acquired by the reference signal acquisition unit 81. The large Barkhausen effect has a BH characteristic as shown in FIG. 4A, that is, a material having a relatively small hysteresis loop and a relatively small holding force (Hc), for example, Co—Fe—Ni—B—. This is a phenomenon in which sharp magnetization reversal occurs when an amorphous magnetic material made of Si is placed in an alternating magnetic field. For this reason, when an alternating current is caused to flow through an exciting coil to generate an alternating magnetic field, and a magnetic material is placed in the alternating magnetic field, a pulsed current flows through a detection coil disposed in the vicinity of the magnetic material during magnetization reversal. Become. For example, when an alternating magnetic field as shown in the upper part of FIG. 4B is generated by the excitation coil, a pulse current as shown in the lower part of FIG. 4B flows through the detection coil. However, an alternating current induced by an alternating magnetic field also flows in the current flowing through the detection coil, and the pulse current is detected by being superimposed on this alternating current. That is, the current generated by the large Barkhausen effect is generated at regular intervals in synchronization with the alternating magnetic field. For this reason, the detection signal acquisition unit 82 acquires only the detection signal for each predetermined period among the detection signals output from the ADC 7, and the reference signal acquired by the reference signal acquisition unit 81 for the determination of this period. Is used. The detection signal acquisition unit 82 acquires the detection signal at a timing that takes into account a delay or the like with respect to the reference signal acquired by the reference signal acquisition unit 81.

  The averaging unit 83 averages the detection signals acquired by the detection signal acquisition unit 82. For example, as illustrated in FIG. 5, if the detection signal acquisition unit 82 acquires detection signals from the ADC 7 at regular intervals, the averaging unit 83 may acquire the acquired detection signals several times (eight times in the figure). Average and output the average value. In FIG. 5, the detection signal is shown as a sine wave, but this is for explanation, and the actual detection signal has AC components removed as described above.

  The comparison unit 84 compares the average value output from the averaging unit 83 with the reference value to determine whether or not there is a possibility that the detection signal may include a signal component generated by the large Barkhausen effect. To do.

  The continuity determination unit 85 confirms the continuity when the comparison unit 84 determines that there is a possibility that the detection signal includes a signal component generated by the large Barkhausen effect. When it is recognized, it is determined that the detection signal includes a signal component generated by the large Barkhausen effect. Further, after determining that the detection signal includes a signal component generated by the large Barkhausen effect, the comparison unit 84 determines that there is no possibility that the detection signal includes a signal component generated by the large Barkhausen effect. In this case, the continuity is confirmed, and when a certain number of continuations are recognized, it is determined that the signal component generated by the large Barkhausen effect has disappeared from the detection signal.

  The adjustment unit 86 uses the determination result by the continuity determination unit 85, the amplification degree of the amplifier 5, the number of detection signals when the average unit 83 calculates the average value, and the reference that the comparison unit 84 uses for comparison. The number of times when the value and continuity determination unit 85 confirms continuity is adjusted.

  Next, the operation flow of the signal determination unit 8 will be described. FIG. 6 is a flowchart showing the flow of signal determination processing by the signal determination unit 8, and FIG. 7 is a flowchart showing the flow of adjustment processing by the signal determination unit 8.

  In the signal determination process, first, the detection signal acquisition unit 82 acquires a detection signal based on the reference signal acquired by the reference signal 81 (step 201), and the averaging unit 83 adds the value of the detection signal (step 201). 202). Then, when the detection signal is acquired and added A times (A is a predetermined natural number) (NO in step 203) and the same process is executed A times (YES in step 203), the averaging unit 83 is added. The average value of the detection signals is calculated by dividing the signal by A (step 204).

  Next, the comparison unit 84 compares the calculated average value with a predetermined reference value (step 205), and if the average value is equal to or greater than the reference value (YES in step 206), the continuity determination unit 85. Performs continuity determination.

  In the continuity determination by the continuity determination unit 85, first, when the previous average value is equal to or greater than the reference value (YES in step 207), the number of consecutive times is counted (step 208), and the counted number of consecutive times When B reaches B times (B is a predetermined natural number) (YES in step 209), it is determined that a signal generated by the large Barkhausen effect has been detected (step 210). That is, the continuity determination unit 85 determines that a signal generated by the large Barkhausen effect is detected when the average value is equal to or more than the reference value B times continuously, and the previous average value is the reference value. If it is less than (NO in step 207) or if the number of consecutive times has not reached B times (NO in step 209), the determination is postponed until the next average value is calculated. .

  On the other hand, as a result of the comparison by the comparison unit 84, if the average value is less than the reference value (NO in step 206), the determination result by the continuity determination unit 85 is “detection” (in step 211). YES), the continuity determination unit 85 determines continuity.

  In the continuity determination by the continuity determination unit 85, first, when the previous average value is less than the reference value (YES in step 212), the number of continuations is counted (step 213), and the counted number of continuations. Has reached C times (C is a predetermined natural number) (YES in step 214), it is determined that the signal generated by the large Barkhausen effect has disappeared, that is, is not detected (step 215). The continuity determination unit 85 determines that the signal generated by the large Barkhausen effect has disappeared when the average value is less than the reference value for C consecutive times, and the previous average value is greater than or equal to the reference value. If there is (NO in step 212), or if the number of consecutive times has not reached C (NO in step 214), the determination is postponed until the next average value is calculated.

  If the average value is less than the reference value as a result of comparison by the comparison unit 84 (NO in step 206), the determination result by the continuity determination unit 85 is “not detected” (step 211). NO), no determination is made, and the state of “non-detection” is continued.

  Next, adjustment processing by the signal determination unit 8 will be described. The adjustment process is performed in a state where a signal due to the large Barkhausen effect is not detected, for example, when a power-on person confirms that a signal due to the large Barkhausen effect is not detected. Done.

  In the adjustment process, first, the adjustment unit 86 fixes the amplification degree of the amplifier 5 (step 301), decreases the values A and B used in the determination process (step 302), and uses these values as the continuity determination unit. The process is repeated until it is determined that 85 detects a signal generated by the large Barkhausen effect (NO in step 303). If the continuity determination unit 85 determines that a signal generated by the large Barkhausen effect has been detected (YES in step 303), a value obtained by adding a predetermined value of a to the value of A at that time is a new value of A. A value obtained by adding a predetermined b value to the B value at that time is set as a new B value (step 304). The values of a and b are added because the continuity determination unit 85 determines that the signal is detected in a state where the signal due to the large Barkhausen effect is not detected in the values of A and B at that time. This is because false detection is caused by noise or the like, and by adding the values a and b to this, it is possible to obtain a value that is not affected by noise or the like.

  Subsequently, the adjustment unit 86 increases the amplification degree of the amplifier 5 (step 305), and repeats this until the continuity determination unit 85 determines that a signal generated by the large Barkhausen effect is detected (NO in step 306). ). If the continuity determination unit 85 determines that a signal generated by the large Barkhausen effect has been detected (YES in step 306), a value obtained by subtracting a predetermined value of d from the amplification degree at that time is a new value of the amplifier 5. The amplification degree is set (step 307). This process is also for removing the influence of noise and the like as described above.

  Note that the adjustment by the adjustment unit 85 can be performed only for one of the values, and the C value used in the determination process can be similarly adjusted.

It is a block diagram which shows the structural example of a signal detection apparatus. 3 is a diagram illustrating a configuration example of a signal determination unit 8. FIG. 3 is a block diagram illustrating a functional configuration example of a signal determination unit 8. FIG. It is a figure for demonstrating the generation principle of the signal by the large Barkhausen effect. It is a figure for demonstrating the acquisition timing of a detection signal, and an averaging process. 5 is a flowchart showing a flow of signal determination processing by a signal determination unit 8. It is a flowchart which shows the flow of the adjustment process by the signal determination part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Signal source 2 Excitation coil 3 Detection coil 4 Filter 5 Amplifier 6 Filter 7 ADC
8 signal determination unit 81 reference signal acquisition unit 82 detection signal acquisition unit 83 averaging unit 84 comparison unit 85 continuity determination unit 86 adjustment unit 101 calculation unit 102 storage unit 103 temporary storage unit 104 information input / output unit

Claims (6)

An acquisition means for acquiring a detection signal at a specific time among detection signals output by a detection means including a signal reception means and an amplification means for amplifying the signal received by the signal reception means;
A comparison means for calculating an average value of the detection signals acquired by the acquisition means and comparing whether or not the calculated average value is equal to or greater than a reference value;
If the can before Symbol comparison by the comparison means that the detection signal is above the reference value results were number of consecutive times a predetermined confirmed, determination is judged to contain a signal caused by large Barkhausen effect on the detection signal Means ,
Adjusting means for adjusting the amplification degree of the amplifying means;
The amplification means of the amplifying means is fixed by the adjusting means in the absence of a signal caused by the large Barkhausen effect, the reference value, the average number of times when the comparing means calculates the average value, and the determining means is continuous. Each value of the number of times of confirmation is varied, and a value obtained by adding a predetermined value to each value when the determination unit determines that the detection signal includes a signal generated by a large Barkhausen effect is a new reference value. And a setting means for setting the average number of times and the number of times of confirming continuity .   After the determination means determines that the detection signal acquired by the acquisition means includes a signal generated by a large Barkhausen effect, it is confirmed that the comparison results in which the detection signal is less than a reference value have continued for a predetermined number of times. 2. The signal detection device according to claim 1, wherein the signal detection unit determines that the signal generated by the large Barkhausen effect has disappeared from the detection signal. The setting means fixes each value of the reference value, the average number of times when the comparison means calculates the average value, and the number of times the determination means confirms continuity in the absence of a signal caused by a large Barkhausen effect. The adjustment means varies the amplification degree of the amplification means, and a value obtained by subtracting a predetermined value from the amplification degree when the determination means determines that the detection signal includes a signal generated by a large Barkhausen effect. The signal detection device according to claim 1 , wherein the signal detection device is set as a new amplification degree. An acquisition process of acquiring a detection signal at a specific time among detection signals output by a detection unit including a signal reception unit and an amplification unit that amplifies the signal received by the signal reception unit;
A comparison process for calculating an average value of the detection signals acquired in the acquisition process and comparing whether the calculated average value is a reference value or more;
If the the comparison result by the comparison process of pre-Symbol detection signal is equal to or greater than the reference value is the number of consecutive predetermined confirmed, determination is judged to contain a signal caused by large Barkhausen effect on the detection signal Processing ,
An adjustment process for adjusting the amplification degree of the amplification means;
The amplification degree of the amplifying unit is fixed by the adjustment process in the absence of a signal caused by the large Barkhausen effect, and the average number of times when the average value is calculated by the reference value and the comparison process, and continuously by the determination process. Each value of the number of times of checking is changed, and a value obtained by adding a predetermined value to each value when the determination process determines that the detection signal includes a signal generated by a large Barkhausen effect is a new reference value. And a signal detection program for causing a computer to execute a setting process for setting the average number of times and the number of times of confirming continuity . After the determination process determines that the detection signal acquired in the acquisition process includes a signal generated by the large Barkhausen effect, it is confirmed that the comparison result that the detection signal is less than a reference value continues for a predetermined number of times. 5. The signal detection program according to claim 4 , wherein when the signal is detected, it is determined that the signal generated by the large Barkhausen effect disappears from the detection signal. In the setting process, each value of the reference value, the average number of times when the comparison unit calculates the average value, and the number of times of confirmation of the continuity in the determination process are fixed in the absence of a signal generated by the large Barkhausen effect. Then, the amplification degree of the amplification means is varied by the adjustment process, and a value obtained by subtracting a predetermined value from the amplification degree when the determination process determines that the detection signal includes a signal generated by the large Barkhausen effect. 6. The signal detection program according to claim 4 , wherein the signal detection program is set as a new amplification degree.

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