JP4747974B2 - Object detection apparatus and object detection method - Google Patents

Description

  The present invention relates to an object detection apparatus and an object detection method that include an excitation coil and a detection coil to detect an object provided with a magnetic wire, and in particular, store and detect a noise waveform of a metal object that becomes a noise source in advance. The present invention relates to an object detection apparatus and an object detection method that can detect a signal from a magnetic wire with high accuracy by calculating a signal waveform and a stored noise waveform.

  In recent years, various methods and apparatuses for enhancing security, such as prevention of leakage of confidential information and personal information, prevention of counterfeiting of securities and the like, prevention of theft of goods and the like, have been provided.

  For example, when a magnetic wire is applied to recording paper or the like that is prohibited from passing through the gate and the recording paper enters the gate, an alternating magnetic field generated by an excitation coil provided on the gate is applied to the recording paper. A technique is known in which magnetization reversal is caused in a magnetic wire and a steep magnetic pulse accompanying the magnetization reversal is detected by a detection coil of a gate to detect a recording paper that has entered the gate.

  Patent Document 1 also includes a magnetic marker embedded in an article, including a magnetic wire that causes a sharp magnetization reversal when an alternating magnetic field is applied, and an on / off control element that generates a bias magnetic field that can prevent the magnetization reversal. When the article is received, the magnetic marker is turned on, the magnetic marker is switched off for the paid article, and if the magnetization reversal of the magnetic marker is detected when the article passes through the exit gate, the article There is provided an article management system for judging that the item is an unsettled article.

Also in the technique of Patent Document 1, an object to which a magnetic wire is applied is detected by detecting a steep magnetic pulse generated by an alternating magnetic field from the magnetic wire applied to the object.
JP 2003-182847 A

  However, in such a technique for detecting a steep magnetic pulse emitted from a magnetic wire by an alternating magnetic field, a notebook PC or steel can whose metal passes through a gate in addition to an object to which a magnetic wire is attached. If a notebook PC or steel can enters the gate while holding the same, the signal from the notebook PC or steel can is detected and the signal from the magnetic wire attached to the object is accurately detected. The problem of not being able to detect well occurs.

  Therefore, the present invention makes it possible to detect a signal from a magnetic wire with high accuracy by storing a noise waveform of a metal object or the like that is a noise source in advance and calculating the detected signal waveform and the stored noise waveform. An object is to provide an object detection device and an object detection method.

To achieve the above object, the object detecting means of the invention of claim 1, an excitation means for generating an alternating magnetic field, detection means for detecting a signal other than the alternating magnetic field in the alternating magnetic field generated by the excitation means If, applying the to the detected signal by detecting means, a confirmation means for confirming whether a pulse signal according to the magnetization reversal of the applied magnetic substance to be detected object is passing through the said alternating magnetic field, the detection object body A storage means for storing in advance a signal detected by the detection means when a known object different from the magnetic body passed through the alternating magnetic field, and when the pulse signal is not confirmed by the confirmation means, arithmetic means for performing an operation for subtracting the signal stored in the storage means from the detected by the detecting means signal, the field in which the pulse signal is confirmed by the calculation by check or said calculation means by said check means To be configured to include a object detecting means for detecting the detection target object passing through the said alternating magnetic field.

Further, the invention of claim 2, in the invention of claim 1, wherein the storage means previously stores a plurality of signals generated in a plurality of known objects, the Starring Sante stage, detected by said detecting means constructed and stored from the signal in the memory means one or more signals to perform an operation of subtracting, respectively.

According to a third aspect of the present invention, in the first or second aspect of the present invention, the storage means outputs, to the known object, a plurality of signals detected by the detecting means corresponding to the passing direction of the known object. corresponding plurality of storage, the Starring Sante stage is configured to perform an operation of subtracting 1 or more signals stored in the storage means from the detected signal by said detecting means, respectively.

According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the storage means outputs the plurality of signals detected by the detection means corresponding to the passing position of the known object. a plurality of stored corresponding to the object of the Starring Sante stage is configured to perform an operation of subtracting 1 or more signals stored in the storage means from the detected signal by said detecting means, respectively.

According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the detected object is provided with a predetermined magnetic body that generates a predetermined signal by an alternating magnetic field generated by the exciting means. It is configured to be a recording paper.

In the object detection method of the invention of claim 6, an alternating magnetic field is generated by the exciting means, a signal other than the alternating magnetic field in the alternating magnetic field generated by the exciting means is detected by the detecting means, and the detecting means In the detected signal, it is confirmed by the confirmation means whether there is a pulse signal due to the magnetization reversal of the magnetic material applied to the detected object passing through the alternating magnetic field, and when the pulse signal is not confirmed by the confirmation means, From the signal detected by the detection means, a signal that is detected by the detection means when a known object different from the magnetic material applied to the detected object passes through the alternating magnetic field and that is stored in advance a calculation for subtracting performed by Starring Sante stage, when the pulse signal by calculation by check or said calculation means by said confirmation means is confirmed, the test passing through the said alternating magnetic field The object to test knowledge.

According to the present invention, an effect that in not high precision can allow detection signals from the magnetic wire.

  Embodiments of an object detection apparatus and an object detection method according to the present invention will be described below in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic diagram showing a detection gate 101 to which an object detection apparatus and an object detection method according to the present invention are applied.

  The detection gate 101 detects the recording paper 103 provided with the magnetic wire 102 between the gates, and prohibits the recording paper 103 from being taken out.

  The magnetic wire 102 is a ferromagnetic material having a large Barkhausen effect of an Fe—Co amorphous material, and is provided in a form to be inserted into the recording paper 103.

  The detection gate 101 generates an alternating magnetic field between the left and right gates by exciting coils provided on the left and right gates, and is generated between the gates when the recording paper 103 provided with the magnetic wire 102 is passed between the gates. Magnetization reversal occurs in the magnetic wire 102 in the recording paper 103 to which an alternating magnetic field is applied, and a steep magnetic pulse is generated.

  This magnetic pulse is a magnetic pulse accompanying the large Barkhausen effect of the magnetic wire 102.

  The detection gate 101 can detect the steep magnetic pulse and detect the recording paper 103 provided with the magnetic wire 102 that attempts to pass through the gate.

  However, if a metal object such as a notebook PC or a steel can is carried through the detection gate 101 together with the recording paper 103 provided with the magnetic wire 102, the metal object such as the notebook PC or the steel can becomes a noise source, and the magnetic wire It becomes difficult to detect the steep magnetic pulse emitted by 102.

  The object detection apparatus and the object detection method according to the present invention provide a notebook PC that is a noise source in advance so that a steep magnetic pulse emitted from the magnetic wire 102 can be detected even if a noise source such as a notebook PC or a steel can is brought together. The signal waveform of the steel wire can be stored, and the calculation process of subtracting the signal waveform of the noise source from the detection signal is performed to detect a steep magnetic pulse emitted from the magnetic wire 102.

  Next, the configuration of the detection gate 101 according to the present invention will be described with reference to FIG.

  FIG. 2 is a block diagram showing the configuration of the detection gate 101 according to the present invention.

  The detection gate 101 includes an excitation coil 201, a detection coil 202, an excitation circuit 203, a detection circuit 204, a waveform storage device 205, a signal processing circuit 206, a calculation circuit 207, and an average waveform calculation circuit 208.

  The detection gate 101 detects a recording sheet 103 provided with a magnetic wire 102 passing between the one side components of the gate constituted by the excitation coil 201 and the detection coil 202 facing each other.

  The exciting coil 201 is connected to the exciting circuit 203, and an alternating current is conducted by the exciting circuit 203 to generate an alternating magnetic field.

  The detection coil 202 is connected to the detection circuit 204, and an induced current due to a change in the generated magnetic field is detected by the detection circuit 204.

  The excitation circuit 203 conducts an alternating current through the excitation coil 201 and generates an alternating magnetic field from the excitation coil 201.

  The detection circuit 204 detects an induced current flowing in the detection coil 202 due to a change in the magnetic field between the gates, and removes an alternating magnetic field component from the induced current.

  The waveform storage device 205 is configured by a memory and removes an alternating magnetic field component detected by a noise source detection circuit 204 that becomes a noise source when the detection gate 101 detects the magnetic wire 102 such as a notebook PC or a steel can. The signal waveform thus recorded is stored.

  The signal processing circuit 206 determines whether or not the signal processed by the detection circuit 204 or the signal waveform calculated by the arithmetic circuit 207 includes a pulse signal corresponding to a steep magnetic pulse emitted from the magnetic wire 102.

  The arithmetic circuit 207 performs arithmetic processing on the signal waveform processed by the detection circuit 204 and the signal waveform of the noise source stored in advance by the waveform storage device 205 to calculate a signal waveform that is free from the influence of the noise source.

  The average waveform calculation circuit 208 performs processing for calculating an average waveform signal of waveform signals measured at a plurality of measurement positions when the waveform signal of the noise source is measured.

  When the recording paper 103 provided with the magnetic wire 102 and the notebook PC 209 are both passed between the detection gates 101 configured as described above, the signal detected by the detection circuit 204 is converted into the magnetic wire 102. If there is no pulse signal corresponding to, the noise signal waveform of the notebook PC 209 stored in the waveform storage device 205 is subtracted from the signal processed by the detection circuit 204 by the arithmetic circuit 207 and processed by the arithmetic circuit 207. The pulse signal corresponding to the magnetic wire 102 is detected by the signal processing circuit 206 in the received signal, and the presence of the magnetic wire 102 between the detection gates 101 can be detected with high accuracy.

  Next, the signal waveform until the signal waveform processed by the detection circuit 204 is arithmetically processed by the arithmetic circuit 207 to obtain the pulse signal of the magnetic wire 102 will be described with reference to FIG.

  FIG. 3 is a diagram showing various signal waveforms. FIG. 3A is obtained from the detection circuit 204 when there is only a recording paper 103 to which the magnetic wire 102 is applied without a noise source between the detection gates 101. FIG. 3B is a diagram illustrating a signal waveform, and FIG. 3B is a diagram illustrating a signal waveform obtained from the detection circuit 204 when only the notebook PC 209 that is a noise source exists between the detection gates 101. FIG. 3D is a diagram showing a signal waveform obtained from the detection circuit 204 when the recording paper 103 and the notebook PC 209 exist between the detection gates 101, and FIG. 3D shows the recording paper 103 and the notebook shown in FIG. This is a signal waveform obtained after the processing for subtracting the signal waveform of the notebook PC 209 shown in FIG. 3B from the signal waveform detected by the PC 209 is performed by the arithmetic circuit 207.

  As shown in FIG. 3A, when only the recording paper 103 provided with the magnetic wire 102 exists between the detection gates 101, a magnetic pulse corresponding to the magnetic wire 102 is obtained from the detection circuit 204.

  As shown in FIG. 3B, when only the notebook PC 209 exists between the detection gates 101, a noise waveform by the notebook PC 209 is obtained from the detection circuit 204, and this noise waveform is stored as a noise waveform by the notebook PC 209. Stored in the unit 205.

  When the recording paper 103 and the notebook PC 209 are brought together between the detection gates 101, the signal waveform obtained from the detection circuit 204 is the signal waveform of the magnetic wire 102 and the notebook PC 209 as shown in FIG. A signal waveform that overlaps with the noise waveform is obtained.

  In the detection gate 101, a signal waveform that cannot be detected by the magnetic wire 102, as shown in FIG. 3C, is detected in a detection circuit 204 in a usage situation for the purpose of detecting the normal recording paper 103 instead of processing for storing the waveform of the noise source. If obtained, the arithmetic circuit 207 performs processing for subtracting the signal waveform of the object (here, the notebook PC 209) stored in the waveform storage unit 205 from the signal waveform obtained from the detection circuit.

  As shown in FIG. 3D, a pulse signal corresponding to the magnetic wire 102 is detected from the signal waveform subtracted by the arithmetic circuit 207 as described above, and the recording paper 103 and the notebook PC 209 are connected to the detection gate 101 together. The recording paper 103 is detected even if it is brought in.

  Next, how signal waveforms of a notebook PC 209, a steel can, and the like that are noise sources are measured in advance and stored in the waveform storage device 205 will be described with reference to FIG.

  FIG. 4 is a diagram illustrating a state in which a signal waveform of a noise source such as a notebook PC 209 or a steel can is measured and stored in advance, and FIG. 4A is a note in the detection gate 101 when the signal waveform is stored. FIG. 4B is a schematic diagram showing a position where the PC 209 is measured, and FIG. 4B is a schematic diagram showing an arrow 401 attached to the notebook PC 209 indicating a reference direction of the notebook PC 209 when the signal waveform of the notebook PC 209 is measured. FIG. 4C shows the magnitude of the magnetic field strength of the noise component of the signal waveform measured at each measured position when the direction of the notebook PC 209 is in the X-axis direction (the arrow 401 is in the X-axis direction). FIG. 4D is a graph of signal waveforms measured at each measurement position in a state where the orientation of the notebook PC 209 is in the Y-axis direction (the arrow 401 is in the Y-axis direction). 4E is a graph showing the magnitude of the magnetic field strength of the component, and FIG. 4E is measured at each measurement position in a state where the direction of the notebook PC 209 is directed in the Z-axis direction (the arrow 401 is the Z-axis direction). 6 is a graph showing the magnitude of the magnetic field strength of the noise component of the signal waveform.

  In order to store the signal waveform of the notebook PC 209 that is a noise source in the waveform storage device 205, the detection gate 101 has a plurality of measured objects on the XZ plane on the center point between the gates as shown in FIG. A position is provided, and the signal waveform of the notebook PC 209 is measured at the position to be measured.

  By providing multiple positions to be measured, the value near the gate where the magnitude of the magnetic field strength of the noise component is expected to be maximum, or at the center of the gate where the magnitude of the magnetic field strength of the noise component is expected to be minimum Can be measured.

  Further, since the noise signal waveform of the notebook PC 209 is different depending on the direction in which the notebook PC 209 faces when the noise signal waveform of the notebook PC 209 is measured at each position to be measured, the notebook PC 209 is measured with being directed in the respective XYZ axis directions. The arrow 401 shown in FIG. 4B is for clarifying the orientation of the notebook PC 209 at that time.

  Graphs showing the magnitude of the magnetic field strength of the noise component of the signal waveform of the notebook PC 209 measured by changing the direction of the notebook PC 209 are shown in FIGS. 4C, 4D, and 4E.

  From the graph shown in FIG. 4C, the maximum value and the minimum value of the magnetic field strength of the noise component when the notebook PC 209 is measured in the X-axis direction are determined, and the maximum value is measured. The signal waveform measured from the measurement position and obtained from the detection circuit 204 is the maximum signal waveform directed in the X-axis direction, and the signal waveform obtained from the detection circuit 204 is measured at the measurement position where the minimum value is measured. Is stored in the waveform storage device 205 as a minimum signal waveform directed in the X-axis direction.

  Similarly, the maximum value and the minimum value of the magnetic field strength of the noise component when the notebook PC 209 is measured in the Y-axis direction are determined from the graph shown in FIG. The signal waveform obtained from the detection circuit 204 measured at the measurement position where the value is measured is measured as the maximum signal waveform directed in the Y-axis direction, and is measured at the measurement position where the minimum value is measured. The obtained signal waveform is stored in the waveform storage device 205 as a minimum signal waveform directed in the Y-axis direction.

  Similarly, the maximum value and the minimum value of the magnetic field strength of the noise component when the notebook PC 209 is measured in the Z-axis direction are determined from the graph shown in FIG. The signal waveform obtained from the detection circuit 204 measured at the measurement position where the value is measured is measured as the maximum signal waveform directed in the Z-axis direction, and is measured at the measurement position where the minimum value is measured. The obtained signal waveform is stored in the waveform storage device 205 as a minimum signal waveform directed in the Z-axis direction.

  Similarly, from the graphs shown in FIGS. 4C, 4D, and 4E, the maximum value and the minimum value of the magnitude of the magnetic field strength of the noise component when the notebook PC 209 does not depend on the direction are found. The signal waveform obtained from the detection circuit 204 measured at the measurement position where the maximum value is measured is obtained as the maximum signal waveform independent of the direction, or obtained from the detection circuit 204 as measured at the measurement position where the minimum value is measured. The stored signal waveform is stored in the waveform storage device 205 as a minimum signal waveform independent of the direction.

  Further, the average waveform calculation circuit 208 performs processing for obtaining an average signal waveform from the signal waveform obtained from the detection circuit 204 when the notebook PC 209 is directed in the X-axis direction and measured at each measurement position. The average signal waveform calculated by the waveform calculation circuit 208 is stored in the waveform storage device 205 as an average signal waveform when the notebook PC 209 faces in the X-axis direction.

  Further, the average waveform calculation circuit 208 performs processing for obtaining an average signal waveform from the signal waveform obtained from the detection circuit 204 when the notebook PC 209 is oriented in the Y-axis direction and measured at each measurement position. The average signal waveform calculated by the waveform calculation circuit 208 is stored in the waveform storage device 205 as an average signal waveform when the notebook PC 209 faces in the Y-axis direction.

  Further, the average waveform calculation circuit 208 performs processing for obtaining an average signal waveform from the signal waveform obtained from the detection circuit 204 when the notebook PC 209 is oriented in the Z-axis direction and measured at each measurement position. The average signal waveform calculated by the waveform calculation circuit 208 is stored in the waveform storage device 205 as an average signal waveform when the notebook PC 209 is peeled in the Z-axis direction.

  Further, the average waveform calculation circuit 208 is a process for obtaining an average signal waveform from the signal waveform obtained by the detection circuit 204 by measuring the notebook PC 209 in the X-axis, Y-axis, and Z-axis directions and measuring at each measurement position. The average signal waveform calculated by the average waveform calculation circuit 208 is stored in the waveform storage device 205 as an average signal waveform independent of the direction of the notebook PC 209.

  In this way, the minimum signal waveform, maximum signal waveform, and average signal waveform that do not depend on the direction of the notebook PC 209, and the minimum signal waveform, maximum signal waveform, and average signal waveform in each of the XYZ directions of the notebook PC 209 are stored in the waveform storage device 205. Is remembered.

  Next, FIG. 5 shows a process for detecting a pulse signal corresponding to a magnetic pulse emitted from the magnetic wire 102 when the signal waveform is detected by the detection circuit 204 of the detection gate 101 and is calculated by the calculation circuit 207. The description will be given with reference to FIG.

  FIG. 5 is a flowchart showing a processing flow of processing in which a signal waveform detected by the detection circuit 204 is subjected to arithmetic processing by the arithmetic circuit 207 and a pulse signal corresponding to a magnetic pulse emitted from the magnetic wire 102 is detected.

  When an object enters the detection gate 101 and a signal waveform other than the alternating magnetic field component is detected by the detection circuit 204 (step 501), the detected signal waveform is recorded on the recording paper 103 that is prohibited from passing through the detection gate 101. The signal processing circuit 206 checks whether or not there is a pulse signal corresponding to the magnetic pulse emitted by the magnetic wire 102 to be applied (step 502). If the pulse signal of the magnetic wire 102 is not detected (NO in step 502). The signal detected by the detection circuit 204 is arithmetically processed with the signal waveform of the noise source (notebook PC 209) stored in the waveform storage device 205 (step 503).

  Then, the signal processing circuit 206 checks whether or not the signal waveform calculated in step 503 includes the pulse signal of the magnetic wire 102 (step 504), and if the pulse signal of the magnetic wire 102 is not detected (step 504). The signal detected by the detection circuit 204 is arithmetically processed with the signal waveform of a noise source (steel can) different from the notebook PC 209 stored in the waveform storage device 205 (step 505).

  Then, in step 505, the signal processing circuit 206 checks whether or not the signal waveform of the steel can and the signal waveform obtained by the calculation processing include the pulse signal of the magnetic wire 102 (step 506). If it is not detected (NO in step 506), the signal detected by the detection circuit 204 is now processed into a signal waveform synthesized by adding the signal waveform of the notebook PC 209 and the signal waveform of the steel can. (Step 507).

  This is a calculation process assuming that a person who intends to pass through the detection gate 101 has both the notebook PC 209 and the steel can and enters the detection gate 101.

  If the pulse signal of the magnetic wire 102 is not detected as a result of the arithmetic processing in step 507 (NO in step 508), it is determined that the recording paper 103 prohibited from passing does not enter between the detection gates 101. It will never be done.

  Further, when the signal waveform obtained by the detection circuit 204 includes a pulse signal of the magnetic wire 102 (YES in step 502), the signal waveform obtained by the detection circuit 204 is processed with the signal waveform of the notebook PC 209. When there is a pulse signal of the magnetic wire 102 in the signal waveform (YES in step 504), or the signal waveform obtained by the detection circuit 204 is a signal waveform obtained by calculating the signal waveform of the steel can and the pulse signal of the magnetic wire 102. (YES in step 506), the signal waveform obtained by the detection circuit 204 is a signal waveform obtained by adding the signal waveform of the notebook PC 209 and the signal waveform of the steel can and the signal waveform obtained by the arithmetic processing. If the pulse signal of the magnetic wire 102 is detected (YES in step 508), the detection gate 101 is not shown. Knowledge buzzer is actuated, the passage of the recording paper 103 that is prohibited is detected is notified (step 509).

  Next, calculation processing of the signal waveform detected by the detection circuit 204 and the signal waveform of the noise source stored in the waveform storage device 205 performed by the arithmetic circuit 207 will be described with reference to FIG.

  FIG. 6 is a flowchart showing arithmetic processing performed by the arithmetic circuit 207, and FIG. 6A is a flowchart showing arithmetic processing with an average signal waveform of the noise source independent of the direction of the noise source itself. FIG. 6B is a flowchart showing a calculation process of the maximum signal waveform, the minimum signal waveform, and the average signal waveform of the noise source that does not depend on the direction of the noise source itself, and FIG. It is a flowchart which shows the calculation process of the maximum signal waveform, minimum signal waveform, and average signal waveform about each direction of XYZ direction in consideration of direction of itself.

  In the flowchart shown in FIG. 5, the arithmetic processing performed in steps 502, 505, 507, and 509 has three methods as shown in FIGS. 6 (a), (b), and (c).

  As shown in FIG. 6A, in the calculation process with the average signal waveform of the noise source that does not depend on the direction of the noise source itself, the signal waveform detected by the detection circuit 204 is stored in the waveform storage device 205. A calculation process is performed to subtract the average signal waveform of the noise source independent of the direction of the noise source itself (step 601).

  Further, as shown in FIG. 6B, in the arithmetic processing of the maximum signal waveform, the minimum signal waveform, and the average signal waveform of the noise source that does not depend on the direction of the noise source itself, first, the signal detected by the detection circuit 204 is detected. The waveform is calculated by the calculation circuit 207 and the minimum signal waveform of the noise source independent of the direction of the noise source stored in the waveform storage device 205 (step 611), and the pulse signal of the magnetic wire 102 is still processed by the signal processing circuit 206. If not detected, the signal waveform detected by the detection circuit 204 is then processed with the average signal waveform of the noise source independent of the direction of the noise source stored in the waveform storage device 205 (step 612). If the pulse signal 102 is not detected, then the signal waveform detected by the detection circuit 204 is a noise source stored in the waveform storage device 206. It is processing the maximum signal waveform of a noise source that is independent of the direction (Step 613).

  When the pulse signal of the magnetic wire 102 is detected by the signal processing circuit 206 in any one of the steps 611, 612, and 613, the detection of the recording paper 103 is notified by a notification buzzer (not shown) provided in the detection gate 101 ( Step 509 in FIG.

  In addition, as shown in FIG. 6C, in the method in which the calculation processing of the minimum signal waveform, the maximum signal waveform, and the average signal waveform is performed in each of the XYZ directions in consideration of the direction of the noise source itself, detection is performed. The signal waveform detected by the circuit 204 is first processed by the calculation circuit 207 with the minimum signal waveform when the noise source is directed in the X direction (step 621), and the pulse signal of the magnetic wire 102 is still processed by the signal processing circuit 206. If the noise source is not detected in step 622, the average signal waveform when the noise source is directed in the X direction and the arithmetic circuit 207 are processed (step 622), and the pulse signal of the magnetic wire 102 is still not detected by the signal processing circuit 206. Next, the maximum signal waveform when the noise source is directed in the X direction and the arithmetic circuit 207 perform arithmetic processing (step 623).

  Even in step 623, if the pulse signal of the magnetic wire 102 is not detected by the signal processing circuit 206, then the signal waveform detected by the detection circuit 204 is calculated with the minimum signal waveform when the noise source is directed in the Y direction. If the pulse signal of the magnetic wire 102 is still not detected (step 624), the average signal waveform when the noise source is directed in the Y direction is processed next (step 625). If the noise source is not detected, the maximum signal waveform when the noise source is directed in the Y direction is processed (step 626).

  If the pulse signal of the magnetic wire 102 is not detected in step 626, the signal waveform detected by the detection circuit 204 is then processed with the minimum signal waveform when the noise source is directed in the Z direction (step 627). If the pulse signal of the magnetic wire 102 is still not detected, the average signal waveform when the noise source is directed in the Z direction is processed (step 628). If the pulse signal of the magnetic wire 102 is still not detected, Next, the maximum signal waveform when the noise source is directed in the Z direction is processed (step 629).

  In any of the processes from step 621 to 629, when the pulse signal of the magnetic wire 102 is detected, the detection buzzer provided in the detection gate 101 notifies the detection of the recording paper 103 (step 509 in FIG. 5). ).

  As described above, the calculation processing with the noise source signal waveform is performed with the noise source average signal waveform, or the noise source minimum signal waveform, maximum signal waveform, average signal waveform calculation processing, or noise There are three ways of calculation processing with the minimum signal waveform, maximum signal waveform, and average signal waveform of the noise source in each direction when the source faces each direction of the XYZ axes, and any method may be performed.

  As described above, when the recording paper 103 provided with the magnetic wire 102 enters the detection gate 101, the recording paper 103 cannot be detected by a metal object (notebook PC, steel can) or the like that simultaneously enters noise. In order to prevent this, a magnetic waveform such as a metal object serving as a noise source is stored in advance, and the magnetic wire 102 is provided with high accuracy by performing arithmetic processing on the detected signal waveform and the stored signal waveform of the noise source. The recording sheet 103 can be detected.

  In the measurement of the signal waveform of the noise source, the signal waveform of the notebook PC 209 is measured at a plurality of measurement positions on the X-Z plane as shown in FIG. The X-Z plane to be translated is translated in the Y-axis direction so that the signal waveform is measured from various positions in the Y-axis direction, and the signal waveform is measured in the entire space between the detection gates 101. Good.

  The calculation processing of the signal waveform detected by the detection circuit 204 and the signal waveform of the noise source stored in the waveform storage device 205 described with reference to FIG. 6 is performed from the signal waveform detected by the detection circuit 204. Although the signal waveform of the noise source has been described as being subtracted, the signal waveform detected by the detection circuit 204 is not simply subtracted, but a process of multiplying the signal waveform of the noise source by a specific coefficient. You may make it subtract.

  In this embodiment, the detection gate 101 has been described as detecting the recording paper 103 to which the magnetic wire 102 has been applied. However, if the object that detects that the magnetic wire 102 has entered between the gates has been provided with the magnetic wire 102, In particular, the present invention is not limited to a recording paper medium.

  The magnetic wire 102 applied to the recording paper 103 may be a ferromagnetic material having a large Barkhausen effect, and is not particularly limited to a medium called a wire.

  The present invention can be used in a detection gate that detects a recording sheet or the like provided with a magnetic wire.

  According to the present invention, the signal waveform of the assumed noise source is stored in advance, and the processing is performed by subtracting the stored signal waveform of the noise source from the signal waveform obtained from the detection circuit, thereby recording the signal waveform on the detection gate. Even when the paper and the noise source are brought in at the same time, the recording paper provided with the magnetic wire can be detected with high accuracy.

The schematic diagram which shows the detection gate 101. FIG. FIG. 2 is a block diagram showing a configuration of a detection gate 101. The figure which showed the signal waveform processed. The figure which shows a mode that the signal waveform of a noise source is measured and memorize | stored. The flowchart which shows the process to the detected signal waveform performed in the detection gate 101. FIG. The flowchart which shows the flow by which the detected signal is arithmetically processed with the signal waveform memorize | stored in the waveform memory | storage device 205. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Detection gate 102 Magnetic wire 103 Recording paper 201 Excitation coil 202 Detection coil 203 Excitation circuit 204 Detection circuit 205 Waveform memory device 206 Signal processing circuit 207 Arithmetic circuit 208 Average waveform calculation circuit 209 Notebook PC

Claims (6)

Excitation means for generating an alternating magnetic field;
Detecting means for detecting a signal other than the alternating magnetic field in the alternating magnetic field generated by the exciting means ;
Confirmation means for confirming whether the signal detected by the detection means has a pulse signal due to magnetization reversal of the magnetic material applied to the detected object passing through the alternating magnetic field;
A storage means for said known object different from the magnetic material has been applied to the detection object body stores in advance the signal sensed by the sensing means when passing through the said alternating magnetic field,
An arithmetic means for performing an operation of subtracting the signal stored in the storage means from the signal detected by the detection means when the pulse signal is not confirmed by the confirmation means;
An object detection apparatus comprising: an object detection unit configured to detect the detected object passing through the alternating magnetic field when the pulse signal is confirmed by confirmation by the confirmation unit or calculation by the calculation unit. The storage means
Pre-store multiple signals generated on multiple known objects,
It said Starring Sante stage,
The object detection apparatus according to claim 1, wherein an operation of subtracting one or a plurality of signals stored in the storage unit from a signal detected by the detection unit is performed. The storage means
Storing a plurality of signals detected by the detecting means corresponding to the passing direction of the known object, corresponding to the known object;
It said Starring Sante stage,
The object detection apparatus according to claim 1, wherein a calculation is performed to subtract one or more signals stored in the storage unit from signals detected by the detection unit. The storage means
Storing a plurality of signals detected by the detecting means corresponding to the passing positions of the known objects, corresponding to the known objects;
The computing means is
The object detection apparatus according to any one of claims 1 to 3, wherein a calculation for subtracting one or a plurality of signals stored in the storage unit from a signal detected by the detection unit is performed. The detected object is
The object detection apparatus according to claim 1, wherein the object detection apparatus is a recording sheet provided with a predetermined magnetic body that generates a predetermined signal by an alternating magnetic field generated by the excitation unit. An alternating magnetic field is generated by the excitation means,
A signal other than the alternating magnetic field in the alternating magnetic field generated by the excitation means is detected by the detection means,
Confirming by the confirmation means whether the signal detected by the detection means has a pulse signal due to the magnetization reversal of the magnetic material applied to the detected object passing through the alternating magnetic field ,
When the pulse signal is not confirmed by the confirmation means, the detection means when a known object different from the magnetic material applied to the detected object passes through the alternating magnetic field from the signal detected by the detection means. a calculation for subtracting the in signal for storing in advance a signal detected conducted by Starring Sante stage,
When said pulse signal is confirmed, the object detection method of detection known the detection target object passing through the said alternating magnetic field by calculation by check or said calculation means by said confirmation means. "

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