JP2009063544A - Information acquiring device, method and system and reflector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide information acquiring device, method and system and an reflector, extracting abundant information from reflected wave from an object, thereby surely discriminating the kind of the object. <P>SOLUTION: At least two or more absorbing materials having bandpass filter characteristic such that different transmission bands are provided in a use band are provided on a base board to form the reflector. The reflector has reflectance of three or more levels to the electric wave with a frequency in the use band. On the other hand, a pattern of reflectance distribution of three or more levels to the frequency in the use band is assigned to every kind of objects, and a reflector having the reflectance distribution of the assigned pattern is given to the object according to the kind. The information acquiring device transmits an electric wave with a frequency extending over the use band, receives an electric wave reflected by the object, extracts a pattern of intensity distribution to the frequency of the received electric wave, and compares the extracted pattern with the pattern assigned to every kind of objects to discriminate the kind of the object. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an information acquisition technique for acquiring information related to a target by a reflected wave received from the target. More specifically, the present invention relates not only to the presence / absence of a target but also to an information acquisition device that can identify its type, its method, its system and its reflector.

Conventionally, as in Patent Document 1, for example, in a moving body such as a vehicle, information acquisition for knowing the presence and distance of surrounding obstacles has been performed. In the technology of Patent Document 1, at least a part of a target is a radio wave reflector that totally reflects one or more specific frequency radio waves and a radio wave absorber that absorbs one or more specific frequency radio waves. It consists of and. Thereby, a selective radio wave reflection characteristic is given to the target. A target having such radio wave reflection characteristics is irradiated with radio waves, and the frequency components of the reflected waves are analyzed. Thereby, information such as the distance and relative speed of the target is extracted. It is also said that information on the type of target can be obtained by obtaining code information corresponding to the radio wave reflection characteristics of the target.
JP 2000-88951 A

  However, the above-described conventional technology still lacks the function of identifying the type of target. The cause is that only the presence or absence of various frequency components in the reflected wave is observed. For this reason, the amount of information was insufficient, and it was not sufficient for reliable identification of the type of target.

  The present invention has been made to solve the above-described problems of the prior art. In other words, the subject is to provide an information acquisition device, method, system, and reflector that can extract abundant information from the reflected wave from the target and thereby reliably identify the type of target. There is.

  In order to solve this problem, the information acquisition method of the present invention assigns a reflectance distribution pattern of three or more levels to the frequency within the use band for each type of target, and assigns the reflectance distribution of the assigned pattern. A reflecting plate is attached to the target according to the type, radio waves with a frequency over the use band are transmitted, radio waves reflected by the target are received, and the intensity distribution pattern for the frequency within the use band of the received radio waves is displayed. By extracting and comparing the extracted pattern with the pattern assigned to each type of target and identifying the type of target that reflected the received radio wave, information on the type of target is obtained. is there.

  The present invention extends to an information acquisition system and an information acquisition device for causing an in-vehicle information acquisition device to acquire information related to a target by the information acquisition method described above. In other words, the information acquisition device includes a transmission unit that transmits radio waves having a frequency over the use band, a reception unit that receives radio waves reflected by the target, and an intensity distribution with respect to frequencies within the use band of the radio waves received by the reception unit. A pattern that identifies the type of target that reflected the radio wave received by the receiver by comparing the pattern extracted by the signal processor with the pattern extracted by the signal processor and the pattern assigned to each target type And a comparison unit. Here, the pattern for each type of target used for the comparison in the pattern comparison may be output from the pattern output unit.

  The present invention also extends to a reflector used in the above information acquisition method. That is, the reflector has a substrate that reflects radio waves of all frequencies in the use band and at least two or more absorbers provided on the substrate, and each absorber has a transmission band in the use band. The bandpass filter characteristics of each absorber are such that at least one of the both end frequencies of the transmission band of each absorber is different from each other, and has a reflectivity of 3 levels or more with respect to radio waves of frequencies within the use band. It is desirable.

  Alternatively, the reflector has a substrate that reflects radio waves of all frequencies in the use band, and at least two or more absorbers provided on the substrate, and each absorber is different from each other in the use band. What has a resonance frequency is used, and it may be configured to have a reflectance of three levels or more with respect to a radio wave having a frequency within a use band.

  In the present invention, by using the above-described reflector, various reflectance patterns having a reflectance of three levels or more can be easily prepared by using a finite number of absorbers. For this reason, it can respond to various kinds of targets. The type of target can be reliably identified with high reliability by the intensity distribution pattern of the reflected wave. For this reason, it is an information acquisition apparatus etc. which can acquire the information about the kind of target object reliably.

  Here, the transmission unit of the information acquisition apparatus can also transmit radio waves with a non-uniform intensity distribution with respect to frequency. In this case, the signal processing unit performs correction based on the transmission intensity distribution in the transmission unit when extracting the intensity distribution pattern from the received radio wave. Thereby, the amount of information can be further increased.

  Further, the reflector can be provided with a switch group for individually switching the grounding state of the absorber. In this case, information can be transmitted from the reflector by operating the switch group according to a time pattern assigned in advance for each type of information. In this case, in the information acquisition device, the signal processing unit also extracts the time change pattern of the radio wave received by the receiving unit, and the pattern output unit also outputs the time pattern assigned in advance for each type of information. The comparison unit may compare the time change pattern extracted by the signal processing unit with the time pattern assigned to each type of information. Thereby, the type of information from the reflector can be identified.

  According to the present invention, there is provided an information acquisition device that can extract abundant information from a reflected wave from a target, thereby reliably identifying the type of the target, its method, its system, and its reflector. .

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the best mode for embodying the present invention will be described in detail with reference to the accompanying drawings. In this embodiment, the present invention is applied to a system that acquires information on surrounding objects for safety in a vehicle such as an automobile. More specifically, this is a system that obtains information about a target by giving a reflector having a specific radio wave reflection characteristic to the target in advance and receiving a reflected wave from the target. In this embodiment, a radio wave of 76 to 77 GHz (hereinafter referred to as “use band”) belonging to the millimeter wave band is used for information acquisition.

  First, the reflecting plate applied to the target will be described. As shown in FIG. 1, the reflector 1 used in this embodiment is obtained by attaching a plurality of absorbent materials 3, 4, and 5 to a substrate 2. The substrate 2 basically reflects radio waves in all the above bands. The absorbers 3 to 5 have band-pass filter characteristics that transmit only radio waves in a specific frequency band obtained by further subdividing the above-described use band and absorb radio waves of other frequencies.

  The example of the absorption characteristic of the absorbers 3-5 is shown in FIG. These transmission bands are different. In the example of FIG. 2, the transmission band of the absorbent 3 and the transmission band of the absorbent 4 have substantially the same width, but do not overlap at all. The transmission band of the absorbent 5 is wider than the former two, and extends from the lower end of the transmission band of the absorbent 3 to the upper end of the transmission band of the absorbent 4. Due to such absorption characteristics, the absorbers 3 to 5 have an effect of attenuating radio waves having a frequency corresponding to the absorption band when the reflector 1 reflects the radio waves. Thereby, the reflected wave having the frequency corresponding to the absorption band is weaker than the reflected wave having the frequency corresponding to the transmission band.

  The reflectance characteristics as a whole of the reflecting plate 1 having these three kinds of absorbing materials 3 to 5 are shown in FIG. From the graph of FIG. 3, it can be seen that the reflectance of the reflector 1 is one of three values depending on the frequency. That is, it is the lowest R1 within the range of 76.0-76.2 GHz and within the range of 76.8-77.0 GHz. Radio waves having a frequency within this range are absorbed by all of the absorbers 3-5. For this reason, the reflectance is the lowest R1.

  It is the highest R3 within the range of 76.2-76.4 GHz and within the range of 76.6-76.8 GHz. A radio wave having a frequency within this range is absorbed by one of the absorbing materials 3 to 5, but not by the remaining two. For this reason, the reflectance is the highest R3. Within the range of 76.4 to 76.6 GHz, R2 is intermediate between R1 and R3. Radio waves having a frequency within this range are absorbed by two of the absorbers 3 to 5 and are not absorbed by the remaining one. For this reason, the reflectance becomes an intermediate R2.

  Of course, those shown in FIGS. 2 and 3 are examples. Various absorption characteristics and combinations of absorbent materials are possible. The frequencies at both ends of the transmission band of the absorber are not limited to 0.2 GHz increments. The number of absorbent materials is not limited to three. In the absorbent material, there may be variations in the depth of the transmission band, that is, the degree of difference in the absorption rate between the transmission band and the absorption band. Therefore, various patterns are possible for the reflectance characteristics of the reflector 1. The number of reflectance levels is not limited to “3”. It may be more multi-level.

  Such an absorbing material can be prepared by using an insulating material such as resin or ceramic as a base material and blending it with an appropriate radio wave absorber. The absorption characteristics illustrated in FIG. 2 can be adjusted by selecting the radio wave absorber to be blended. An edge with a sharp absorption rate can be realized at the boundary between the absorption band and the transmission band.

  And the reflectance characteristic of FIG. 3 can be adjusted by the combination of these absorbers. For example, a reflectance characteristic as shown in FIG. 4 is also possible. The sharpness of the edge in these reflectance characteristics can also be made favorable. Hereinafter, the reflectance characteristic of FIG. 3 is referred to as “pattern A”, and the reflectance characteristic of FIG. 4 is referred to as “pattern B”. Then, the reflector 1 having the reflectance characteristic of the pattern A is assigned to the pedestrian, the reflector 1 having the reflectance characteristic of the pattern B is assigned to the vehicle, and so on.

  Next, an information acquisition apparatus in the system of this embodiment will be described. The information acquisition device 10 of this embodiment is mounted on a vehicle such as an automobile as part of a driver support device, and is configured as shown in the block diagram of FIG. 5 includes a transmission antenna 11, a reception antenna 12, a transmission unit 13, a reception / signal processing unit 14, a pattern output unit 15, a pattern comparison unit 16, and a command unit 17. Thereby, the information acquisition apparatus 10 functions as an FM-CW radar. Of course, the transmitting antenna 11 and the receiving antenna 12 can also be used as a single antenna.

  The transmission unit 13 is a block that outputs a radio wave toward the target 20 through the transmission antenna 11 while changing the frequency with time over the entire use band. The reception / signal processing unit 14 is a block that acquires a reception signal from the reception antenna 12, performs normal processing such as amplification and noise removal, and performs various arithmetic processing. The specific purpose is to extract a pattern as shown in FIGS. 2 and 3 from the reflected wave returned from the target 20. For this purpose, it is sufficient to have a fast Fourier transform (FFT) or other known arithmetic functions.

  The pattern output unit 15 is a block that outputs various patterns shown in FIGS. For this purpose, the pattern output unit 15 stores necessary patterns. Furthermore, the type of the assigned target is also stored as exemplified in Table 1. Hereinafter, the pattern stored in the pattern output unit 15 is referred to as a “registered pattern”. It should be noted that it is sufficient to store only the portion within the use band of the patterns shown in FIGS. 2 and 3 as the registered pattern.

  The pattern comparison unit 16 is a block that compares the pattern extracted by the reception / signal processing unit 14 with the registered pattern output from the pattern output unit 15. That is, this is a block for determining which of the registered patterns stored in the pattern output unit 15 matches the pattern extracted by the reception / signal processing unit 14. The command unit 17 is a block for issuing various command signals to the vehicle side in accordance with the determination result in the pattern comparison unit 16.

  The system of this embodiment operates as follows. Here, it is assumed that the target 20 in FIG. 5 includes the reflector 1 shown in FIG. First, the transmission unit 13 always transmits a radio wave subjected to frequency modulation as shown in the graph of FIG. That is, the frequency of the transmission wave periodically changes between 76 GHz, which is the lower limit of the use band, and 77 GHz, which is the upper limit. The waveform is a triangular wave, and the period is represented by T in FIG. One period T is about 3 msec. The waveform may be a sawtooth wave instead of a triangular wave. When this is integrated over time and the relationship between frequency and transmission intensity is shown, the graph in FIG. 7 is obtained.

  Then, if the target 20 is near, the information acquisition apparatus 10 receives the reflected wave from the reflecting plate 1 by the receiving antenna 12. The frequency of the reception signal basically changes in the same manner as the transmission wave shown in FIG. However, the received reflected wave should have some frequency components attenuated by the absorbers 3 to 5 of the reflector 1. Therefore, the relationship between frequency and reception strength should be different from that at the time of transmission shown in FIG.

  Therefore, the information acquisition apparatus 10 performs processing according to the procedure shown in FIG. That is, first, the reception / signal processing unit 14 performs arithmetic processing on the received signal. Thereby, the relationship between the frequency and the reception intensity in the received signal is extracted. Thereby, for example, a pattern of reception intensity as shown in FIG. 9 is obtained. Actually, only the portion of the used bandwidth should be considered.

  Then, in the information acquisition device 10, the pattern comparison unit 16 compares the received pattern (for example, FIG. 9) with the registered pattern (for example, FIG. 3 or FIG. 4) of the pattern output unit 15. Of course, it is only the portion of the bandwidth used that is actually compared. Thereby, it is determined which of the registered patterns the received pattern matches. At this time, the vertical axis of the reception pattern may be matched by expansion / contraction or vertical movement as appropriate. This is because the intensity of the reflected signal is influenced by factors such as the distance between the information acquisition device 10 and the target 20. As a result, when a registered pattern matching the received pattern is found, the type of the target 20 to which the pattern is assigned can be specified by referring to Table 1. If it is the reception pattern of FIG. 9, it matches with the pattern A of FIG. 3, and can identify that the type of the target 20 is a pedestrian.

  Thereby, the “special control” in FIG. 8 can be performed. The special control is control according to the type of the identified target 20. Specifically, it is a warning to a driver using an in-vehicle audio device or an image device, or a forced stop of the vehicle. This control is executed by a control device (navigation device, engine control unit, etc.) on the vehicle side. Therefore, a command signal based on the processing result in the pattern comparison unit 16 is transmitted from the command unit 17 to the control device on the vehicle side. Note that “normal control” in FIG. 8 is control according to the direction and distance of the target 20. Extraction of such information from the reflected wave has already been realized so far, so that normal control can be easily performed together with the special control described above.

  Thus, in the information acquisition system of this embodiment, the reflector 1 having a reflectance pattern corresponding to the type of the target 20 is provided in advance. Thereby, the driver | operator of the vehicle carrying the information acquisition apparatus 10 can receive the suitable driving assistance according to the kind, if the target 20 which approached is equipped with the reflecting plate 1. FIG.

  Here, in this embodiment, as described above, the reflector 1 having a reflectance of three levels or more according to the frequency is used. Furthermore, the number of sections where the reflectance is constant on the frequency axis can be made larger than the five sections shown in FIG. For example, a pattern as shown in FIG. 10 is also possible. FIG. 10 shows an example of a pattern of 4 levels and 10 sections. Moreover, even the reflector 1 having a complicated pattern as shown in FIG. 10 can be easily realized by combining a finite number of absorbers.

Therefore, it is possible to prepare as many as ²⁸ to ¹⁰ patterns in total. For this reason, it can cope with various types of targets. Although shown only briefly in Table 1 above, pedestrians can be further classified into infants, boys, middle-aged, elderly, etc., and a unique pattern can be assigned to each. For automobiles, a unique pattern can be assigned for each of the front, rear, and side parts of the vehicle, in addition to the types of ordinary cars and large cars. For vehicles other than automobiles, unique patterns can be assigned to bicycles, wheelchairs, strollers, and the like. For things fixed on the land, a unique pattern can be assigned to each type of building, utility pole, road sign, etc. And the edge of the reflectance in the reflecting plate 1 may be steep as described above, and the information acquisition device 10 can reliably determine the edge.

  While driving on the road, you may encounter a scene such as that shown in FIG. This scene is a situation where a child 31 is behind the power pole 30 and an elderly person 32 is in front of the mail post 33 at a place where the power pole 30 and the mail post 33 are on both sides of the road 40 ahead. FIG. 11 illustrates a situation in which a scene in front of the vehicle is displayed on the monitor screen of the navigation device. Even when such a scene is encountered, if each target object (electric pole 30, child 31, elderly person 32, post box 33) is provided with each reflector 1, the information acquisition device 10 can reliably select the type. Recognize existence while identifying. Thereby, appropriate driving support according to the type of the specified object is also possible.

  Further, the intensity distribution of the transmission wave shown in FIG. 7 can be modified. FIG. 12 shows an example of the modification. In FIG. 7, the transmission intensity is uniform over the entire use band, but in FIG. 12, the transmission intensity increases linearly to the right. That is, the higher the frequency, the stronger the transmission intensity.

  When transmission is performed with such a transmission intensity distribution, the reception pattern naturally has an effect. That is, instead of the reception pattern of FIG. 9, the reception pattern of FIG. 13 is obtained from the target 20 having the reflectance pattern of FIG. In this case, the reception pattern in FIG. 13 is corrected in consideration of the transmission intensity distribution in FIG. 12, and then used for comparison with the registered pattern. The transmission intensity distribution data for this purpose may be provided from the transmission unit 13 to the reception / signal processing unit 14. Thereby, the type of the target can be identified as in the case of using the transmission intensity distribution of FIG.

  As a result, the amount of information can be further enriched. For example, even when another vehicle equipped with the same information acquisition device 10 is nearby, it is possible to eliminate the influence of a transmission wave from the other vehicle. This is because, by using different transmission intensity distributions for the own vehicle and other vehicles, the reception pattern due to the transmission wave of the other vehicle does not match the registered pattern. As a result, even in an environment where traffic is congested, noise from other vehicles can be eliminated and more accurate discrimination can be performed. Of course, the transmission intensity distribution according to the modification is not limited to that shown in FIG.

  Further, the reflecting plate is not limited to that shown in FIG. One example is shown in FIG. The example shown in FIG. 14 is a modification that realizes the reflectance characteristics of the reflector by combining patch antennas. 14 has patch antennas 31-33. The patch antenna has a resonance frequency corresponding to the length of its side. Therefore, it has a high absorption rate for radio waves of the resonance frequency, but does not absorb much radio waves of other frequencies. The shorter the side, the higher the resonance frequency. Further, not only the resonance frequency but also the absorption capacity is different for each patch antenna 31 to 33. For this reason, the reflecting plate 30 has a reflectance of three levels or more according to the frequency.

  The patch antennas 31 to 33 of the reflecting plate 30 have different side lengths and have resonance frequencies f1, f2, and f3. The resonance frequencies f1, f2, and f3 are all frequencies within the use band. The patch antennas 31 to 33 are connected to the ground via the switches SW1 to SW3, respectively. The reflector 30 can have eight reflectance patterns by turning on and off the switches SW1 to SW3. Such a reflector 30 can be used in place of the reflector 1 shown in FIG. Of course, the number of patch antennas is not limited to “3”, but may be more or “2”.

  FIG. 15 shows another modified reflector. The reflector 40 in FIG. 15 uses linear antennas 41 to 43 instead of the patch antenna. A straight antenna has a resonance frequency corresponding to its length. The lengths of the linear antennas 41 to 43 are different from each other. Thereby, the function similar to what was shown in FIG. 14 can be show | played. FIG. 16 shows an example of a reflector 50 provided with slits 51 to 53 having different lengths. The slit also has a different resonance frequency depending on its length. For this reason, although operation with a switch is impossible, a different reflectance pattern is realizable by the combination of whether slits 51-53 are provided. An example in which the slits 52 and 53 are provided without the slit 51 is shown in FIG.

  In the case of the reflector having the switch shown in FIGS. 14 and 15, the amount of information can be further increased by using the time axis by operating the switch. FIG. 18 shows an application example thereof. FIG. 18 shows an example in which patch antennas 31 to 33 and switches SW1 to SW3 are provided on a roadside electronic sign 60. The entire electronic sign 60 has a function as the reflector 30 in FIG. 14 in addition to the original visual display function.

  The electronic sign 60 is further provided with a controller 61 for operating the switches SW1 to SW3. The controller 61 can operate the switches SW1 to SW3, for example, as shown in the timing chart of FIG. Thereby, the reflectance pattern of the electronic sign 60 can be modulated with time. Since the millimeter wave radar scan is performed at about 1.5 msec / scan, a sufficient number of bits can be obtained by modulating at a frequency of 10 MHz or higher. As a result, the amount of information can be further greatly increased. For example, information such as a temporary change in the regulated speed due to weather or the approach of the end of the traffic jam can be transmitted from the electronic sign 60 to the in-vehicle information acquisition device 10.

  For this purpose, an operation pattern according to time as shown in FIG. 19 may be determined in advance for each type of information as described above. Then, the controller 61 operates the switches SW1 to SW3 with the operation pattern assigned to the information to be transmitted at that time. On the other hand, on the vehicle side, the pattern output unit 15 in FIG. 5 needs to output a time pattern as shown in FIG. Further, the reception / signal processing unit 14 also extracts the time change pattern of the reception signal. The pattern comparison unit 16 also compares the time change pattern of the received signal with the time pattern output from the pattern output unit 15. Thereby, the type of information transmitted from the electronic sign 60 can be identified by the in-vehicle information acquisition device 10.

  Of course, such usage is not limited to that shown in FIG. Furthermore, in addition to the case where the target is a fixed object such as a road sign, even a movable object can be modulated by a switch if it is equipped with a power source such as an automobile.

  As described in detail above, in the information acquisition system of this embodiment, the reflector is configured by a combination of absorbers having bandpass filter characteristics. Alternatively, the reflector is configured by a combination of antennas having different resonance frequencies. For this reason, the reflectance pattern of a reflecting plate can be prepared very variously. Thereby, a unique reflectance can be assigned to each of various types of the target 20. Also, since the edge characteristic of the reflectance is good, the information acquisition apparatus can reliably identify the type of the target object based on the intensity distribution of the received reflected wave. In this way, a highly reliable information acquisition method and the like are realized.

  Note that this embodiment is merely an example, and does not limit the present invention. Therefore, the present invention can naturally be improved and modified in various ways without departing from the gist thereof. For example, the bandwidth to be used may be appropriately determined according to the legal system of the country or region where it is used. Further, the pattern output unit 15 is not limited to storing a necessary pattern by itself. A storage area may be provided outside the information acquisition apparatus 10 such as on the network, and the necessary pattern may be acquired by accessing the storage area when necessary.

It is a perspective view which shows the reflecting plate which concerns on embodiment. It is a graph which shows the example of the transmission characteristic of the absorber used for the reflecting plate of embodiment. It is a graph which shows the example (pattern A) of the reflectance characteristic of the reflecting plate of embodiment. It is a graph which shows another example (pattern B) of the reflectance characteristic of the reflecting plate of embodiment. It is a block diagram which shows the structure of the information acquisition apparatus of embodiment. It is a graph which shows the frequency of the transmission wave from the information acquisition apparatus of embodiment. It is a graph which shows intensity distribution with respect to the frequency of the transmission wave from the information acquisition apparatus of embodiment. It is a figure which shows the procedure of the process after the reflected wave reception in the information acquisition apparatus of embodiment. It is a graph which shows the example of the intensity distribution with respect to the frequency of the received wave in the information acquisition apparatus of embodiment. It is a graph which shows another example of the reflectance characteristic of the reflecting plate of embodiment. It is a schematic diagram of an example of the scene encountered while driving a vehicle. It is a graph which shows the modification of the intensity distribution of a transmission wave. It is a graph which shows the example of intensity distribution of the received wave concerning a modification. It is a block diagram of the reflecting plate (the 1) which concerns on a modification. It is a block diagram of the reflecting plate (the 2) which concerns on a modification. It is a block diagram of the reflecting plate (the 3) which concerns on a modification. It is a block diagram of the reflecting plate (the 3) which concerns on a modification. It is a figure which shows the application example of the reflecting plate of FIG. It is a timing chart which shows an example of switch operation.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reflector 2 Board | substrates 3-5 Absorber 10 Information acquisition apparatus 11 Transmitting antenna 12 Receiving antenna 13 Transmitting part 14 Reception / signal processing part 15 Pattern output part 16 Pattern comparison part 20 Target 30 Reflecting plates 31-33 Patch antenna (absorption) body)
40 Reflectors 41-43 Linear antenna (absorber)
50 reflector

Claims (14)

A transmitter that transmits radio waves of a frequency that covers the band used;
A receiver for receiving radio waves reflected by the target;
A signal processing unit for extracting a pattern of intensity distribution with respect to a frequency within a use band of radio waves received by the receiving unit;
A pattern output unit for outputting a pattern of a reflectance distribution of three levels or more with respect to a frequency within a use band allocated in advance for each type of target;
A pattern comparison for comparing the intensity distribution pattern extracted by the signal processing unit and the reflectance distribution pattern output from the pattern output unit to identify the type of target that reflected the radio wave received by the receiving unit And an information acquisition device. In the information acquisition device according to claim 1,
The transmission unit transmits radio waves with a non-uniform intensity distribution with respect to frequency, and the signal processing unit extracts the intensity of transmission in the transmission unit when extracting a pattern of intensity distribution from the received radio waves. An information acquisition apparatus characterized by performing correction based on distribution. In the information acquisition device according to claim 1 or 2,
The signal processing unit also extracts a time change pattern of the radio wave received by the receiving unit,
The pattern output unit also outputs a time pattern assigned in advance for each type of information,
The pattern comparison unit also identifies the type of information from the target by comparing the time variation pattern extracted by the signal processing unit with the time pattern assigned to each type of information. Information acquisition device. Assign a reflectance distribution pattern of three or more levels for each frequency of the target band for each target type,
A reflector with a reflectance distribution of the assigned pattern is given to the target according to the type,
Transmits radio waves with a frequency spanning the band used from the information acquisition device,
The information acquisition device receives the radio wave reflected by the target,
Extracting a pattern of intensity distribution with respect to a frequency within a use band of a radio wave received by the information acquisition device;
An information acquisition method comprising: comparing an extracted intensity distribution pattern with a reflectance distribution pattern assigned to each type of target, and identifying the type of target reflecting the received radio wave. In the information acquisition method according to claim 4, as the reflector,
A substrate that reflects radio waves of all frequencies within the operating band;
Having at least two or more absorbers provided on the substrate;
Each absorber has a band-pass filter characteristic with a transmission band within the use band,
A method for acquiring information, wherein at least one of both end frequencies of a transmission band of each absorbent material is different from each other. In the information acquisition method according to claim 4, as the reflector,
A substrate that reflects radio waves of all frequencies within the operating band;
Having at least two or more absorbers provided on the substrate;
An information acquisition method, wherein each absorber has a resonance frequency different from each other within a use band. The information acquisition method according to claim 6,
A switch group for individually switching the ground state of the two or more absorbers is provided on the reflector,
Operate the switch group according to the time pattern assigned in advance for each type of information,
Extract the time change pattern of the radio wave received by the information acquisition device,
An information acquisition method characterized in that the type of information from the reflector is also identified by comparing the extracted time variation pattern with a time pattern assigned to each type of information. In an information acquisition system that attaches a reflector according to the type of the target and causes the in-vehicle information acquisition device to acquire information about the target.
Assign a reflectance distribution pattern of three or more levels for each frequency of the target band for each target type,
The reflector attached to the target shall have the reflectance distribution of the pattern assigned to the type.
As the information acquisition device,
A transmitter that transmits radio waves of a frequency that covers the band used;
A receiver for receiving radio waves reflected by the target;
A signal processing unit for extracting a pattern of intensity distribution with respect to a frequency within a use band of radio waves received by the receiving unit;
A pattern for comparing the intensity distribution pattern extracted by the signal processing unit with the reflectance distribution pattern assigned to each type of target and identifying the type of target reflecting the radio wave received by the receiving unit An information acquisition system using a comparator. In the information acquisition system according to claim 8, as the reflector,
A substrate that reflects radio waves of all frequencies within the operating band;
Having at least two or more absorbers provided on the substrate;
Each absorber has a band-pass filter characteristic with a transmission band within the use band,
An information acquisition system characterized in that at least one of both end frequencies of the transmission band of each absorbent material is different from each other. In the information acquisition system according to claim 8, as the reflector,
A substrate that reflects radio waves of all frequencies within the operating band;
Having at least two or more absorbers provided on the substrate;
An information acquisition system, wherein each absorber has a resonance frequency different from each other in a use band. The information acquisition system according to claim 10,
In the reflector,
A group of switches for individually switching the ground state of the two or more absorbers;
A control unit for operating the switch group according to a time pattern assigned in advance for each type of information,
The signal processing unit also extracts a time change pattern of the radio wave received by the receiving unit,
The pattern comparison unit also identifies the type of information from the reflector by comparing the time variation pattern extracted by the signal processing unit with the time pattern assigned to each type of information. Information acquisition system. A substrate that reflects radio waves of all frequencies within the operating band;
Having at least two or more absorbers provided on the substrate;
Each absorber has a band-pass filter characteristic with a transmission band within the use band,
At least one of the two end frequencies of the transmission band of each absorber is different from each other,
A reflector for information acquisition, characterized in that it has a reflectivity of 3 levels or more with respect to radio waves having a frequency within a use band. A substrate that reflects radio waves of all frequencies within the operating band;
Having at least two or more absorbers provided on the substrate;
Each absorber has a different resonance frequency within the operating band.
A reflector for information acquisition, characterized in that it has a reflectivity of 3 levels or more with respect to radio waves having a frequency within a use band. The information acquisition reflector according to claim 13,
A group of switches for individually switching the ground state of the two or more absorbers;
And a control unit for operating the switch group in accordance with a time pattern previously assigned to each type of information.

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