JP4991413B2 - Object detection device - Google Patents

Description

  The present invention relates to an object detection device that detects an object embedded in a structure or in the ground or an object existing on the back side of the structure by electromagnetic waves.

  Conventionally, as a technique for detecting an object embedded in a structure such as a reinforced concrete wall or in the ground (for example, an embedded pipe) by using electromagnetic waves, an antenna unit that transmits and receives pulsed electromagnetic waves from the structure surface or the ground surface. By moving the antenna to a plurality of antenna positions along the reference plane, receiving the electromagnetic wave transmitted from the antenna unit and reflected by the object at each antenna position, and converting the received electromagnetic signal into an electric signal. It is known to detect (see, for example, Patent Document 1).

  In this type of object detection, the received signal received by the antenna unit need not only the reflected wave component corresponding to the electromagnetic wave reflected by the object existing behind the reference plane, but also the electromagnetic wave reflected by the reference plane, etc. Wave component is included. The unnecessary wave component is normally common to each antenna position, and takes a steady value unless the measurement environment changes greatly.

  Here, the intensity of the received signal received at each antenna position is set as intensity data at each sampling interval of a predetermined interval, and a set of the intensity data for each antenna position is stored in the storage unit as a data string for each position, and a plurality of antennas are stored. It is considered that a set of a plurality of sampling timings of the average value is assumed as an unnecessary wave component by calculating an average value of intensity data at the same sampling timing at the position. In this case, the reflected wave component is calculated by subtracting the calculated unnecessary wave component from the position-specific data string at each antenna position.

In the invention described in Patent Document 1, the average value of the intensity data at all antenna positions is not set as an unnecessary wave component, but the intensity at the antenna position to be calculated of the reflected wave component and the plurality of antenna positions before and after the antenna position. The average value of the data is an unnecessary wave component.
JP-A-10-132950 (page 4-5)

  By the way, in a reinforced concrete wall, for example, a plurality of reinforcing bars are arranged at regular intervals along the reference plane in the concrete. For this reason, when a resin pipe or the like existing in a reinforced concrete wall is detected as an object, the electromagnetic wave transmitted from the antenna unit is also reflected by a non-object (here, a reinforcing bar) other than the object. In other words, the reflected wave component corresponds to the reflected wave at the non-target object and appears regularly at equally spaced antenna positions, and the reflected wave component at the antenna position corresponding to the target object corresponding to the reflected wave at the target object. Two components are included: an object reflection component that appears. Therefore, when a plurality of non-target objects and target objects are mixed, the target reflection component may be buried in the non-target reflection component, so that the target object may not be detected. In particular, the intensity of the target reflection component in the reflected wave component is higher than the intensity of the non-target reflection component, for example, when an object such as a resin pipe exists behind a non-target object having a relatively high reflectance such as a reinforcing bar. If it becomes smaller, it becomes very difficult to detect the object.

  The present invention has been made in view of the above reasons, and provides an object detection apparatus capable of detecting only an object from among the object and a non-object arranged at equal intervals along a reference plane. The purpose is to do.

  According to the first aspect of the present invention, an electromagnetic wave is intermittently transmitted from the antenna portion toward the reference plane at a plurality of antenna positions along the reference plane set in the detection area, and the detection target existing in the back of the reference plane Object detection for detecting an object by receiving an electromagnetic wave reflected by an object and a plurality of non-objects arranged at equal intervals along the reference plane by the antenna unit and converting the electromagnetic wave into a received signal that is an electric signal Sampling in which the intensity of the received signal received at each antenna position is set as intensity data for each sampling timing at a predetermined interval, and a set of the intensity data for each antenna position is stored in the storage unit as a data string for each position. And a plurality of antennas such that a set of antenna positions corresponding to each non-object based on the data string for each position is one section. An average received wave group obtained by taking an average value of the data string for each position at each antenna position having the same relative positional relationship with respect to the plurality of sections. And a pattern generation means for generating a pattern data string by fitting each to each section, and an object reflection corresponding to an electromagnetic wave reflected by the object by subtracting the pattern data string from the position-specific data string A corrected reflected wave calculating means for calculating a corrected reflected wave component in which the component is emphasized; and an analyzing means for detecting the state of the object based on the intensity of the corrected reflected wave component at a plurality of the antenna positions. It is characterized by that.

  According to this configuration, the pattern data sequence generated by the pattern generation unit is equivalent to the electromagnetic wave reflected by the reference plane, etc., and the unwanted wave components that constantly appear at all antenna positions are equally spaced along the reference plane. For example, a non-target reflection component corresponding to an electromagnetic wave reflected by a non-target object such as a reinforcing bar in reinforced concrete is added. Therefore, the corrected reflected wave component calculated by subtracting the pattern data string from the position-specific data string in the corrected reflected wave calculation means emphasizes the target reflected component corresponding to the electromagnetic wave reflected by the object. As a result, for example, when an object such as a resin pipe exists behind a non-object having a relatively high reflectivity such as a reinforcing bar, the intensity of the object reflection component in the reflected wave component is the intensity of the non-object reflection component. Even if it becomes smaller than this, the analysis means can detect the state of the object based on the intensity of the corrected reflected wave component. That is, there is an advantage that only the target object can be detected from the target object and the non-target objects arranged at equal intervals along the reference plane.

  According to a second aspect of the present invention, in the first aspect of the present invention, the pattern generating means corresponds to the non-target reflection corresponding to the electromagnetic wave reflected by the non-target object in the plurality of sections before obtaining the average received wave group. It has a correction means which correct | amends the said data string for every position in each division so that the said sampling timing of a component may align.

  According to this configuration, it is possible to obtain an average received wave group that accurately reproduces the shape of the waveform of the position-specific data string in each section, so that the target reflected component can be accurately reproduced in the corrected reflected wave component, and consequently There is an advantage that the detection accuracy is improved.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the pattern generation unit may include the data string for each position for the sections excluding the section in which the target reflection component is included in the data string for each position. The average received wave group is obtained by taking an average value.

  According to this configuration, it is possible to generate a pattern data string excluding the influence of the target reflection component, and as a result, it is possible to accurately reproduce the target reflection component in the corrected reflected wave component, leading to an improvement in detection accuracy. There is.

  Since the present invention detects the state of the object based on the intensity of the corrected reflected wave component in which the object reflection component corresponding to the electromagnetic wave reflected by the object is emphasized, the object is detected at regular intervals along the object and the reference plane. There is an effect that only the target object can be detected from the arranged non-target objects.

(Embodiment 1)
The object detection apparatus according to the present embodiment receives an electromagnetic wave by receiving a transmission signal that is an electric signal by an antenna, and also receives an electromagnetic wave by the antenna and converts it into a reception signal that is an electric signal (FIG. 1A 2), and as shown in FIG. 2, the antenna unit 1 is moved from the antenna unit 1 to the reference plane 20 at a plurality of (here, n) antenna positions X1 to Xn along the reference plane 20 composed of the structure surface or the ground surface. The target object 21 is detected by transmitting the electromagnetic wave intermittently toward and receiving the electromagnetic wave reflected by the target object 21 located behind the reference plane 20 by the antenna unit 1. In the present embodiment, the antenna unit 1 is moved along the reference plane 20 in order to transmit and receive electromagnetic waves by the antenna unit 1 at a plurality of antenna positions X1 to Xn. In FIG. The direction is indicated by an arrow a.

  As shown in FIG. 1A, the object detection device generates and outputs a timing signal that determines a reception period after transmission of the transmission signal and the electromagnetic wave, and is output from the signal generation unit 2. A first signal processing unit 3 that performs signal processing on the transmitted signal to transmit a pulsed electromagnetic wave from the antenna unit 1, and receives a reception signal from the antenna unit 1 during the reception period at each antenna position X1 to Xn. And a second signal processing unit 4 that processes each received signal and detects the object 21. Furthermore, the memory | storage part 5 which memorize | stores the various data used for the signal processing in the 2nd signal processing part 4, the output part 6 which outputs the detection result in the 2nd signal processing part 4, etc., the signal generation part 2, and Provided are a control unit 7 that controls the signal processing method (including the output contents of the output unit 6) of each signal processing unit 3 and 4, and an input unit 8 that is operated to give various instructions to the control unit 7. It has been.

  Here, the signal generation unit 2 generates a transmission signal and a timing signal based on the control signal from the control unit 7, gives the transmission signal to the first signal processing unit 3, and sends the timing signal to the second signal processing unit. Give to 4. The first signal processing unit 3 performs processing such as amplification on the input transmission signal and transmits electromagnetic waves from the antenna unit 1.

  As shown in FIG. 1B, the second signal processing unit 4 amplifies the received signal from the antenna unit 1 and converts the intensity of the amplified received signal into digital intensity data at every sampling interval of a predetermined interval. Sampling means 9 that converts and stores the data in the storage unit 5 and a calculation unit 10 that detects the object 21 using the intensity data stored in the storage unit 5 are provided. Each means of the second signal processing unit 4 is realized by appropriately applying a program to a microcomputer, for example. However, the means is not limited to the microcomputer, but includes an FPGA (Field Programmable Gate Array), an ASIC (Application Specific Integrated Circuit), and the like. It is also possible to use it. In the storage unit 5, each antenna position X1 to Xn and each sampling timing are paired and stored in association with each intensity data, and the intensity data substantially includes the antenna positions X1 to Xn and the sampling timing. Is formed in a two-dimensionally arranged data map. Here, a set of intensity data in the storage unit 5 for each antenna position X1 to Xn is defined as a data string for each position.

  Further, in the following description, each antenna is so arranged that a data string for each position corresponding to the received signal received at the antenna position X1 is A1, and a data string for each position corresponding to the received signal received at the antenna position X2 is A2. The data sequences for each position corresponding to the reception signals received at the positions X1 to Xn are respectively referred to as the data sequences for each position A1 to An. FIG. 3A shows a position-specific data string A3 when the antenna unit 1 is at the antenna position X3. In FIG. 3A, the horizontal axis is the propagation time which means the elapsed time from the time of electromagnetic wave transmission, and the vertical axis is the intensity.

  Each position-specific data string A1 to An is sampled by the sampling means 9 to be expressed as a set of a plurality of intensity data. Here, by setting the time interval of the sampling timing to Δt [s] as shown in FIG. 3B, each position data string A1 to An is represented by a total of m intensity data (elements). Shall. That is, the data string for each position A1 = [intensity data A1 (1), intensity data A1 (2),..., Intensity data A1 (m)], the data string for each position A2 = [intensity data A2 (1), intensity Data A2 (2),..., Intensity data A2 (m)],..., Position-specific data string An = [intensity data An (1), intensity data An (2),. (M)].

  Incidentally, the position-specific data strings A1 to An shown in FIG. 4C are obtained by combining the unnecessary wave component of FIG. 4A and the reflected wave component of FIG. 4B. In FIG. 4, waveforms corresponding to a plurality of antenna positions X1 to Xn are arranged in the vertical axis direction with the horizontal axis representing propagation time and the vertical axis representing intensity. The unnecessary wave component here means an electromagnetic wave that is not reflected by the object 21 but reflected by the reference surface 20 or the surface of the object detection device. When the antenna unit 1 having a transmission antenna that transmits electromagnetic waves and a reception antenna that receives electromagnetic waves is used, a direct wave that directly propagates from the transmission antenna to the reception antenna is also included in the unnecessary wave component. These unnecessary wave components appear uniformly at all antenna positions X1 to Xn, and take steady values as long as the measurement environment does not change greatly.

  The reflected wave component corresponds to an electromagnetic wave reflected by an object deeper than the reference surface 20. Here, what is included in the reflected wave component is not limited to that reflected by the object 21 to be detected. That is, for example, as shown in FIG. 2, when a resin pipe or the like embedded in a reinforced concrete wall is used as the object 21, a large number of non-object rebars are present along the reference plane 20 in the medium 22 made of concrete. Since the electromagnetic waves transmitted from the antenna unit 1 are regularly arranged at equal intervals, the electromagnetic waves transmitted from the antenna unit 1 are also reflected by a number of non-objects (here, reinforcing bars) 23 other than the object (here, resin pipes) 21. become. As a result, the reflected wave component corresponds to the reflected wave at the non-target object 23 and appears regularly at the equally spaced antenna positions X1 to Xn, and the reflected wave component corresponds to the reflected wave at the target object 21. Two components including the target reflection component appearing at the antenna positions X1 to Xn corresponding to the object 21 are included. In addition, although noise components such as randomly generated thermal noise may be included in the position-specific data strings A1 to An as unnecessary wave components, they are unnecessary if the noise components are ignorable compared to the reflected wave components. The noise component in the wave component is ignored. If the noise component cannot be ignored, an appropriate filter process may be performed to remove the noise component. As a filter, there are many options such as an IIR (Infinite Impulse Response) filter, an FIR (Finite Impulse Response) filter, or a window function such as a Hamming Window or a Chebyshev approximation applied thereto. Yes, these may be adopted as appropriate.

  The calculation unit 10 includes an unnecessary wave calculation unit 11 that calculates an unnecessary wave component common to the antenna positions X1 to Xn, and an unnecessary wave that calculates a reflected wave component by subtracting the unnecessary wave component from the position-specific data strings A1 to An. The removing means 12, the partitioning means 13 for partitioning the antenna positions X1 to Xn into a plurality of sections each including a position corresponding to the non-object 23 by using the reflected wave component, and the position-specific data for the plurality of sections Pattern generation means 14 for generating a pattern data string by fitting averages of columns A1 to An to the respective sections, and a target reflection component by subtracting the pattern data string from the position-specific data strings A1 to An Corrected reflected wave calculation means 15 for calculating the corrected reflected wave component with emphasis on the intensity of the corrected reflected wave component at a plurality of antenna positions X1 to Xn Based on and a analysis means 16 for detecting the state of the object 21.

  Hereinafter, the operation of the object detection device of the present embodiment will be described with reference to the flowchart of FIG. Here, a case will be described in which a resin pipe embedded in a reinforced concrete wall in which non-objects (rebars) 23 are arranged at equal intervals as shown in FIG.

  Step S1 in FIG. 5 is initialization, and various parameters set here (i = 0, setting of noise component calculation method, etc.) may be determined in advance, and values taken in by the input unit 8 It may be.

  Subsequently, in steps S <b> 2 and S <b> 3, the position-specific data strings A <b> 1 to An of the antenna positions X <b> 1 to Xn are individually taken into the storage unit 5. The data strings A1 to An for each position are fetched until the necessary number of data strings (that is, the number n of antenna positions X1 to Xn) is reached (S4, S5). Here, each time the new position-specific data strings A1 to An are captured, the already-acquired position-specific data strings A1 to An are shifted one by one (S2). As a result, after the position-specific data strings A1 to An are once fetched by the number n of data strings and the analysis result is obtained by the analysis means 16 described later, every time one new position-specific data string A1 to An is fetched, Analysis by the analysis means 16 can be newly performed in a state where only the data strings A1 to An for each position are updated. That is, the newest position-specific data strings A1 to An can be replaced with the oldest position-specific data strings A1 to An. Similarly, other signal processing methods that can replace the old and new position-specific data strings A1 to An may be used for capturing the position-specific data strings A1 to An.

  The intensity data is also stored at the same sampling timing (same propagation time) in the storage unit 5, and constitutes hourly data strings B1 to Bm, respectively. That is, a set of intensity data at the first sampling timing in the received data sequences A1 to An for each position [intensity data A1 (1), intensity data A2 (1),..., Intensity data An (1)] is obtained. The hourly data string B1, and thereafter the hourly data string B2 = [intensity data A1 (2), intensity data A2 (2),..., Intensity data An (2)],. Bm = [intensity data A1 (m), intensity data A2 (m),..., Intensity data An (m)].

  In step S <b> 6, in order to calculate the unnecessary wave component Y <b> 1 from the position-specific data strings A <b> 1 to An, the unnecessary wave calculation unit 11 first extracts intensity data from the storage unit 5 for each hourly data string B <b> 1 to Bm. Each of the hourly data strings B1 to Bm has sections 1, 2,..., N,... Obtained by cutting the position-specific data strings A1 to An in FIG.4 (c) at the same sampling timing (same propagation time). .. equivalent to m. Here, the average value Y1 (j) of the intensity data is obtained as a representative value for each hourly data string B1 to Bm. That is, for the hourly data string B1, an average value Y1 (1) represented by {A1 (1) + A2 (1) +... + An (1)} / n is obtained, and the same processing is performed for every hour. Repeat for data strings B2 to Bm. The unnecessary wave calculating means 11 uses the set [Y1 (1), Y1 (2),..., Y1 (m)] of the average value Y1 (j) calculated in this way for all sampling timings as unnecessary wave components. Output as Y1. At this time, the noise component can be removed by performing an appropriate filter process on the unnecessary wave component Y1. What was mentioned above should just be used as a filter. The representative values of the hourly data strings B1 to Bm obtained for calculating the unnecessary wave component Y1 are not limited to the average value of the intensity data, and the median value (median value) of the intensity data, the mode value, etc. However, since the method using the average value of intensity data as a representative value is the simplest, there is an advantage that the signal processing speed can be increased.

  In step S <b> 7, the unnecessary wave removing unit 12 subtracts the output (unwanted wave component Y <b> 1) of the unnecessary wave calculating unit 11 from the position-specific data strings A <b> 1 to An in the storage unit 5, thereby obtaining the antenna positions X <b> 1 to Xn. The reflected wave component C1 is obtained.

  However, the reflected wave component C1 obtained in step S7 includes the non-target reflection component that regularly appears at the equally spaced antenna positions X1 to Xn and the target that appears at the antenna positions X1 to Xn corresponding to the target object 21 as described above. Two components, the reflection component, are included, and it is difficult to detect only the object 21 from the reflected wave component C1 including these two components. Therefore, in the present embodiment, the corrected reflected wave component C2 in which the target reflected component is emphasized is calculated using the reflected wave component C1 by the processing described below.

  Here, first, since the partitioning means 13 partitions the data strings A1 to An for each position based on the reflected wave component C1, the maximum value of the reflected wave component C1 is obtained for each antenna position X1 to Xn in step S8. The intensity data (hereinafter referred to as “maximum data”) and the propagation time of each maximum data are detected. In FIG. 6A, the vertical axis represents antenna positions X1 to Xn, the horizontal axis represents propagation time, and the maximum data is represented by black dots. The maximum data here may be intensity data that becomes maximum when the intensity data is compared among the reflected wave components C1, but the correlation of each reflected wave component C1 with respect to the reference waveform is taken. At this time, the intensity data having the maximum correlation value may be the maximum data. Hereinafter, a set of antenna positions X1 to Xn arranged in the order in which the antenna unit 1 moves is represented by Q1 (= [X1, X2,..., Xn]), and a set of maximum data corresponding to the set Q1 is P1 ( = [P1 (1), p1 (2),..., P1 (n)]), and a set of propagation times corresponding to the set P1 is T1 (= [t1 (1), t1 (2),. , T1 (n)]).

  In the next step S9, the partitioning means 13 maximizes the intensity when the maximum data included in the set P1 is arranged in the same order as the antenna positions X1 to Xn as shown in FIG. b), the antenna positions X3,..., X (n−1), which are indicated by “p2”), are detected (eight positions are detected in the example of FIG. 6). In FIG. 6B, the horizontal axis represents antenna positions X1 to Xn, and the vertical axis represents intensity. The set of antenna positions X3,..., X (n-1) detected at this time is represented by Q2 (= [X3,..., X (n-1)]), and the maximum data corresponding to the set Q2 P2 (= [p2 (3),..., P2 (n-1)]), and a set of propagation times corresponding to the set P2 is T2 (= [t2 (3),..., T2 ( n-1)]).

  Further, as shown in FIG. 6 (b) in the set P2, it corresponds to the maximum data p2 (3),..., P2 (n−1) whose intensity is within the predetermined range W1, and the set T2 Among them, as shown in FIGS. 6A and 6C, the antenna positions X3 corresponding to the propagation times t2 (3),..., T2 (n−1) in which the time is within the predetermined range W2. , X (n−1) is detected as a reference position. In FIG. 6C, the horizontal axis represents the antenna positions X1 to Xn, and the vertical axis represents the propagation time, which represents the propagation time of the maximum data included in the set T1. Here, it is assumed that the ranges in which more than half of the elements are distributed for each of the sets P2 and T2 are the predetermined ranges W1 and W2, and k reference positions are detected (in the example of FIG. 6, k = 5). A set of reference positions detected at this time is represented by Q3 (= [X3,..., X (n-1)]), and a set of maximum data corresponding to the set Q3 is represented by P3 (= [p3 (3), .., P3 (n-1)]), and a set of propagation times corresponding to the set P3 is defined as T3 (= [t3 (3),..., T3 (n-1)]). Each reference position of the set Q3 thus obtained represents the position of the non-objects (rebars here) 23 arranged at equal intervals.

  Then, as shown in FIG. 7A, the partitioning unit 13 includes antenna positions X1 to X1 in a plurality of sections D (r) each including the respective reference positions and L antenna positions X1 to Xn before and after each reference position. Xn is divided (here, r = 1, 2,..., K). Here, L satisfies the condition of L ≧ {(maximum distance between adjacent reference positions in Q3) / 2} so that all the antenna positions X1 to Xn are included in any section D (r). Is set as follows. At this time, the data strings A1 to An for each position are also partitioned so as to create a set R3 (r) for each section D (r) of the antenna position, and each set R3 (r) is defined as a received wave group. That is, the received wave group R3 (r) corresponding to the section D (r) including a certain reference position Xu (here 1 ≦ u ≦ n) is R3 (r) = [A (u−L), A (u −L + 1),..., A (u−1), A (u), A (u + 1),..., A (u + L)]. . When k reference positions are detected, k such received wave groups R3 (r) exist. In FIG. 7A, the horizontal axis is the propagation time, the vertical axis is the intensity, and each waveform corresponding to the plurality of antenna positions X1 to Xn (the left side data strings A1 to An and the right side is the reflected wave component). ) In the vertical axis direction.

  In the next step S10, the pattern generation means 14 averages the plurality of received wave groups R3 (r) obtained in step S9 to obtain an average received wave group R4. That is, for the k received wave groups R3 (r) shown in FIG. 7B, the strengths of the data strings A1 to An for each position between the antenna positions X1 to Xn having the same relative positional relationship with respect to each reference position. The average received wave group R4 (= {R3 (1) + R3 (2) +... + R3 (k)} / k) shown in FIG. 7C is calculated. This average received wave group R4 corresponds to the electromagnetic wave reflected by the non-target object 23 among the reflected wave components to the unnecessary wave component Y1 that constantly appears at all the antenna positions X1 to Xn for one section D (r). To which a non-target reflection component is added. It should be noted that it is desirable to remove the noise component by applying an appropriate filter process to the average received wave group R4.

  In the subsequent step S11, the pattern generation means 14 applies the average received wave group R4 to each section D (r) of the antenna positions X1 to Xn described above, thereby performing the average reception as shown in FIG. A pattern data string Y2 having a plurality of wave groups R4 arranged in the direction in which the antenna positions X1 to Xn are arranged is generated. The average received wave group R4 is fitted so that the center antenna positions X1 to Xn are aligned with the reference position that is the center of each section D (r). Here, as described above, when L is set so that all the antenna positions X1 to Xn are included in any of the sections D (r), the pattern data string Y2 corresponds to all the antenna positions X1 to Xn. However, when the reference position is deviated from the regular interval, a part of the adjacent sections D (r) overlap. Therefore, with respect to the overlapping part between adjacent sections D (r), the process of setting the antenna positions X1 to Xn that are intermediate between the reference positions of both sections D (r) as a break when fitting the average received wave group R4, Then, a process of taking the average value of the overlapping average received wave group R4 is applied.

  As described above, the pattern data string Y2 obtained by the pattern generation unit 14 is, for all antenna positions X1 to Xn, an unnecessary wave component Y1 that constantly appears at all antenna positions X1 to Xn, and an equal interval among reflected wave components. The non-target reflection component that appears (corresponding to the electromagnetic wave reflected by the non-target 23) is added. Therefore, in the next step S12, the corrected reflected wave calculation means 15 subtracts the output (pattern data string Y2) of the pattern generation means 14 from the position-specific data strings A1 to An in the storage unit 5 to thereby determine the position of each antenna. It is possible to extract the corrected reflected wave component C2 that emphasizes the target reflected component included in the reflected wave component C1 with respect to X1 to Xn.

  For example, when the position-specific data strings A1 to An actually include reflected wave components (hereinafter referred to as “actual reflected wave components”) as shown in FIG. When the maximum data, which is the maximum value of the reflected wave component C1 with respect to Xn, is arranged such that the vertical axis indicates the intensity and the horizontal axis indicates the antenna positions X1 to Xn, as shown in FIG. Both the target reflection component and the target reflection component appear as peaks (the portion surrounded by a broken line in the figure is the target reflection component). Therefore, in the state of FIG. 8B, it is not possible to distinguish between the target reflection component and the non-target reflection component. 8A, 8 </ b> C, and 8 </ b> E, the waveforms corresponding to the plurality of antenna positions X <b> 1 to Xn are arranged in the vertical axis direction with the horizontal axis representing propagation time and the vertical axis representing intensity.

  Here, in the configuration in which the reflected wave component is obtained by subtracting the unnecessary wave component from the position-specific data strings A1 to An as in the conventional example described in the background art section, the reflected wave component is shown in FIG. As shown, it is similar to the actual reflected wave component of FIG. Therefore, even if the maximum data that is the maximum value of the reflected wave component for each antenna position X1 to Xn is arranged so that the vertical axis indicates the intensity and the horizontal axis indicates the antenna positions X1 to Xn, as shown in FIG. In FIG. 8B, both the target reflection component and the non-target reflection component appear as peaks (the portion surrounded by a broken line in the figure is the target reflection component), and the target reflection component and the non-target reflection component still remain. Can not be distinguished. Therefore, it is difficult to detect only the object 21 from the reflected wave component including these two components. The reflected wave component obtained in this conventional example corresponds to the reflected wave component C1 obtained by the processing up to step S7 of this embodiment (that is, the unnecessary wave component Y1 is subtracted from the position-specific data strings A1 to An). .

  In contrast, the corrected reflected wave component C2 obtained in step S12 (that is, the pattern data string Y2 subtracted from the position-specific data strings A1 to An) has the non-target reflected component as shown in FIG. When the maximum data that is the maximum value of the corrected reflected wave component C2 is arranged for each antenna position X1 to Xn so that the vertical axis represents intensity and the horizontal axis represents antenna positions X1 to Xn, As shown in FIG. 8F, the target reflection component is emphasized (the portion surrounded by the broken line in the figure is the target reflection component), and only the target 21 can be easily detected.

  The analyzing unit 16 of the present embodiment analyzes the corrected reflected wave component C2 for the plurality of antenna positions X1 to Xn obtained by the corrected reflected wave calculating unit 15 as described above in step S13, and the intensity of the corrected reflected wave component C2 The presence / absence of the object 21 is detected depending on whether or not exceeds a predetermined threshold. Here, the intensity of the corrected reflected wave component C2 varies depending on the reflectance of the electromagnetic wave at the object 21, and the reflectance varies depending on the material of the object 21, so that the threshold is set to the electromagnetic wave in the object 21 of a specific material. Therefore, only an object 21 made of a specific material can be detected by ignoring an object having an electromagnetic wave reflectance smaller than that of the object 21. The analysis means 16 may be configured to detect a state other than the presence or absence of the object 21 based on the corrected reflected wave component C2. For example, based on the elapsed time from when the electromagnetic wave is transmitted until it is received. The distance to the target object 21, the size, shape or material of the target object 21, and the characteristics (for example, dielectric constant) of the medium (wall material, etc.) 22 existing between the antenna unit 1 and the target object 21 Can be detected by the analysis means 16. Actually, since the attenuation amount of the electromagnetic wave varies depending on the propagation distance, the propagation distance is calculated from the time required for the electromagnetic wave to be received by the antenna unit 1 after being transmitted from the antenna unit 1 and the speed of the electromagnetic wave, By considering the attenuation effect, each characteristic can be detected with higher accuracy. In addition, since the propagation speed of the electromagnetic wave differs depending on the medium 22, when the material of the medium 22 is known, the propagation distance can be calculated with higher accuracy based on the characteristics (electrical characteristics) of the medium 22. In this case, the assumed characteristics of the medium 22 may be stored in the storage unit 5 in advance, but may be set freely from the input unit 8.

  Here, according to the configuration of the present embodiment, the corrected reflected wave component C2 in which the target reflected component is emphasized can be calculated as described above, and therefore, the analyzing unit 16 analyzes the corrected reflected wave component C2. Various analysis results obtained are less affected by the non-object 23.

  Various analysis results obtained by the analysis means 16 are output from the output unit 6 in step S14. The output unit 6 includes a display monitor (not shown) for displaying the analysis result in a visually recognizable form. In addition, the output unit 6 stores a device such as a speaker for outputting sound and the analysis result. And a storage device, an arithmetic unit for performing further detailed analysis, and the like may be added to support various output forms. In most applications, not only the process from the process (S2) of fetching the data strings A1 to An for each antenna position X1 to Xn into the storage unit 5 to the output of analysis results (S14) is performed once, Repeat. In this case, the process is repeated again from step S2 (S15).

  By the way, in order to detect the target 21 existing behind the reference surface 20 composed of the structure surface or the ground surface, generally, the electromagnetic wave is transmitted and received at the plurality of antenna positions X1 to Xn as described above. Collect signals. In the present embodiment, in order to transmit and receive electromagnetic waves at a plurality of antenna positions X1 to Xn, moving means for moving the object detection device itself so that the antenna unit 1 moves to each antenna position X1 to Xn (see FIG. 2). (Not shown). As the moving means, a configuration having wheels that roll on the reference plane 20 is adopted. However, the configuration is not limited to this configuration. For example, the object detection device is moved along a rail passing through a plurality of antenna positions X1 to Xn. The structure etc. to be made can be considered. Here, the antenna unit 1 is configured to transmit an electromagnetic wave from one antenna and receive the electromagnetic wave through the antenna, thereby reducing the size of the antenna unit 1.

  Further, the antenna unit 1 may have a configuration including one transmitting antenna that transmits electromagnetic waves and one receiving antenna that receives electromagnetic waves. In this case, the antenna unit 1 is moved to each antenna position X1 to Xn. A moving means is provided. Furthermore, the antenna unit 1 may include a plurality of antennas that transmit and receive electromagnetic waves, or may include a plurality of sets of transmission antennas and reception antennas. Moving means for moving to the antenna positions X1 to Xn is provided.

  Here, when a pair of a transmitting antenna and a receiving antenna is arranged at each antenna position X1 to Xn, or when an antenna for transmitting and receiving electromagnetic waves is arranged at each antenna position X1 to Xn, respectively. By using one set of transmission antennas and one reception antenna (or one antenna each), and sequentially switching the combination of transmission antennas and reception antennas used (or antennas used), Since the antenna positions X1 to Xn can be switched without moving the part 1, the moving means can be omitted.

  In this embodiment, an example in which resin piping in reinforced concrete is detected as the object 21 is shown. However, the present invention is not limited to this example, and various objects such as embedded boxes and concrete deterioration and cracks may be detected. Can be detected as.

(Embodiment 2)
In the object detection device of the present embodiment, before the pattern generation unit 14 obtains the average received wave group R4, the sampling timings of the non-target reflection components are aligned in the plurality of sections D (r). It differs from the object detection device of the first embodiment in that it has correction means (not shown) for correcting the position-specific data strings A1 to An.

  That is, when the non-objects 23 arranged at equal intervals along the reference surface 20 are reinforcing bars, the distance from the reference surface 20 to the non-object 23 may vary. In this case, the non-target reflection component corresponding to the reflected wave at each non-target object 23 in the reflected wave component varies in the propagation time direction, but the waveform shape itself can be regarded as substantially the same. Therefore, in the present embodiment, the correction means adjusts the components of the received wave group R3 (r) (position-specific data strings A1 to A1) based on the elements of the set T3 so that the propagation times of the maximum data at the respective reference positions are aligned. An) is corrected to shift in the propagation time direction (that is, the vertical direction in FIG. 6C). If the average received wave group R4 is calculated after correcting each component of the received wave group R3 (r) in this way, the average reception that accurately reproduces the shape of the waveform of each received wave group R3 (r). Since the wave group R4 can be obtained, there is an advantage that the target reflected component can be accurately reproduced in the corrected reflected wave component C2 and the detection accuracy is improved as a result.

  Note that when the pattern data string Y2 is generated in step S11, not only the variation in the distance to the non-object 23 but also the intensity variation and the propagation time shift that appear due to the size variation of the non-object 23 are affected. Therefore, the position-specific data strings A1 to An may be corrected so as to eliminate these influences.

  Other configurations and functions are the same as those of the first embodiment.

(Embodiment 3)
In the object detection device of this embodiment, in step S10 in which the pattern generation unit 14 obtains the average received wave group R4, all received wave groups R3 corresponding to the section D (r) including the component (reference position) of the set Q3. Instead of obtaining the average received wave group R4 from (r), the average received wave group R4 is obtained using the remaining received wave group R3 (r) excluding the received wave group R3 (r) including the target reflection component. This is different from the object detection device of the first embodiment.

  Specifically, the antenna positions X1 to Xn that are determined to correspond to the position of the object 21 among the antenna positions X1 to Xn included in the set Q2 and not corresponding to the reference position (that is, not included in the set Q3). , And the received wave group R3 (r) corresponding to the section D (r) including the antenna positions X1 to Xn at several places before and after the exclusion standard is excluded when calculating the average received wave group R4. Here, whether or not the antenna positions X1 to Xn included in the set Q2 correspond to the positions of the target object 21 is, for example, that the maximum data regarding the antenna positions X1 to Xn and the antenna positions X1 to Xn at several locations is a hyperbola. If they are arranged in a line, it is determined that they correspond.

  In short, since the received wave group R3 (r) is extracted at all the antenna positions X1 to Xn, a part of the received wave group R3 (r) includes the target reflected component among the reflected wave components. . Therefore, when all the received wave groups R3 (r) are averaged to obtain the average received wave group R4, the target reflection component affects the pattern data string Y2 generated using the average received wave group R4, and correction is performed. Although it becomes impossible to accurately emphasize only the target reflection component in the reflected wave component C2, according to the configuration of the present embodiment, the pattern data string Y2 excluding the influence of the target reflection component can be generated. In addition, there is an advantage that the target reflected component can be accurately reproduced in the corrected reflected wave component C2 and the detection accuracy is improved. Note that the configuration of the present embodiment can be combined with the configuration of the second embodiment.

  Other configurations and functions are the same as those of the first embodiment.

1 shows Embodiment 1 of the present invention, where (a) is a schematic block diagram, and (b) is a schematic block diagram of a main part. It is operation | movement explanatory drawing same as the above. (A) is explanatory drawing which shows the data string for every position same as the above, (b) is explanatory drawing to which a part Z of (a) was expanded. It is operation | movement explanatory drawing same as the above, (a) is explanatory drawing which shows an unnecessary wave component, (b) is explanatory drawing which shows a reflected wave component, (c) is explanatory drawing which shows the data string for every position. It is a flowchart which shows operation | movement same as the above. It is operation | movement explanatory drawing same as the above. It is operation | movement explanatory drawing same as the above. It is operation | movement explanatory drawing same as the above.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Antenna part 5 Memory | storage part 9 Sampling means 13 Partitioning means 14 Pattern production | generation means 15 Correction | amendment reflected wave calculation means 16 Analysis means 20 Reference surface 21 Target object 23 Non-object A1-An Data string for every position C2 Correction | amendment reflected wave component R4 Average Received wave group X1 to Xn Antenna position Y2 Pattern data string

Claims (3)

  An electromagnetic wave is intermittently transmitted from the antenna unit toward the reference plane at a plurality of antenna positions along the reference plane set in the detection area, and the detection target existing behind the reference plane and along the reference plane An object detection device for detecting an object by receiving electromagnetic waves reflected by a plurality of non-objects arranged at equal intervals by the antenna unit and converting the electromagnetic waves into a reception signal which is an electric signal, each antenna Sampling means for storing the intensity of the received signal received at the position at each sampling timing of a predetermined interval and storing the set of the intensity data for each antenna position in the storage unit as a data string for each position; and the data for each position A plurality of the antenna positions are divided into a plurality of sections so that a set of the antenna positions corresponding to each non-object based on the column is one section. An average received wave group obtained by taking an average value of the data string for each position at each antenna position having the same relative positional relationship with respect to a plurality of the sections, respectively, for each section, Pattern generation means for generating a pattern data string by fitting, and correction in which the object reflection component corresponding to the electromagnetic wave reflected by the object is emphasized by subtracting the pattern data string from the position-specific data string An object comprising: corrected reflected wave calculation means for calculating a reflected wave component; and analysis means for detecting the state of the object based on the intensity of the corrected reflected wave component at a plurality of the antenna positions. Detecting device.   The pattern generation means, before obtaining the average received wave group, the position in each section so that the sampling timing of the non-object reflection component corresponding to the electromagnetic wave reflected by the non-object in the plurality of sections is aligned. 2. The object detecting apparatus according to claim 1, further comprising a correcting unit that corrects each data string.   The pattern generation means obtains the average received wave group by taking an average value of the data string for each position for the sections excluding the section in which the target reflection component is included in the data string for each position. The object detection device according to claim 1 or 2.

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