JP2009257823A - Ultrasonic three-dimensional distance measurement apparatus and ultrasonic three-dimensional distance measurement method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ultrasonic three-dimensional distance measurement apparatus and an ultrasonic three-dimensional distance measurement method for accurately measuring a three-dimensional position and a three-dimensional shape of an object without threshold determination. <P>SOLUTION: The ultrasonic three-dimensional distance measurement apparatus for measuring the three-dimensional position and the three-dimensional shape of the object comprises: an ultrasonic transmitting element for transmitting ultrasonic waves; a plurality of ultrasonic receiving elements 1; an amplification means 2; an A-D conversion means 3; a direct wave removing means 4; a signal strength changing means 5; a noise removing means 6; a delay means 7; a multiplication means 8; and a three-dimensional position calculating means 9 as main components. The signal strength changing means 5 performs half-wave rectification processing of a fourth received signal S4. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an ultrasonic three-dimensional distance measuring device and an ultrasonic three-dimensional distance measuring method.

  Conventionally, there has been a measurement technique in which a reflected wave generated by reflection of an ultrasonic wave transmitted from an ultrasonic transmission element on an object is received by the ultrasonic wave reception element, and a distance to the object is measured based on the obtained reception signal. Are known.

  Also, a technique for detecting an incident angle of a reflected wave by receiving a reflected wave from an object by a plurality of ultrasonic receiving elements and performing predetermined processing on a reception signal obtained by each ultrasonic receiving element. Is known (see Patent Documents 1 and 2). Here, the predetermined process is to change the delay time in the delay addition. The delay addition is to add after delaying a predetermined time to the signal obtained by each ultrasonic receiving element. This predetermined time to delay is called delay time. The delay time is calculated by the incident angle of the reflected wave to be detected (hereinafter referred to as a deflection angle) and the distance between the centers of the ultrasonic receiving elements, and the distance between the centers of the ultrasonic receiving elements is fixed. The delay time depends on the deflection angle. When the delay time is changed and a peak is obtained after delay addition, the deflection angle corresponding to the delay time is the incident angle of the reflected wave, that is, the direction of the object. In some cases, multiplication is performed instead of addition in delay addition (hereinafter, this processing is referred to as delay multiplication).

  Obtaining information of the incident angle of the reflected wave along the scanning direction by this predetermined processing is hereinafter referred to as “electronic scanning”. That is, “electronic scanning” means obtaining information on the incident angle of the reflected wave along the scanning direction by changing the delay time in delay multiplication or delay addition (hereinafter the same).

If electronic scanning is performed in one direction, information on the incident angle of a one-dimensional reflected wave can be obtained. Therefore, if electronic scanning is performed in different directions, for example, directions perpendicular to each other, information on the incident angle of the two-dimensional reflected wave can be obtained. By adding the distance information to the object to the incident angle information, the three-dimensional position and the three-dimensional shape of the object reflecting the ultrasonic wave can be measured. Such measurement is hereinafter referred to as ultrasonic three-dimensional distance measurement.
JP 2002-156451 A JP 2007-121045 A

  By the way, directivity is not good for electronic scanning using only delay addition or delay multiplication. For example, it is assumed that the ultrasonic receiving elements 1 are arranged in a 6 × 6 lattice pattern as shown in FIG. 13A with the center-to-center distance being half λ / 2 of the wavelength λ of the reflected wave of the ultrasonic wave. To do. In FIG. 13A, the left-right direction is X, the up-down direction is Y, the direction perpendicular to the paper surface is the Z direction, and the positive direction is the right, top, and back to front surface. It is assumed that the reflected wave is along the XZ plane, and the incident angle of the reflected wave (arrow in FIG. 5B) on the XZ plane is α as shown in FIG. Let θ be the incident angle (deflection angle) of the reflected wave to be detected that determines the delay time in electrical scanning in the XZ plane. Both the incident angle α and the deflection angle θ are positive when the reflected wave is incident from the positive side of the X axis, and negative when the reflected wave is incident from the negative side of the X axis.

  FIG. 14 shows a result of simulation when electronic scanning is performed in the X-axis direction (along the XZ plane) when the incident angle α of the reflected wave is 0 °. The case where delay addition is used for electronic scanning is shown in FIG. 5A, and the case where delay multiplication is used is shown in FIG. When either delay addition or delay multiplication is used, a peak appears in the range of the deflection angle θ other than 0 °. When a peak at a deflection angle θ other than 0 ° is detected, a reflected wave is actually incident from the deflection angle θ direction although no reflected wave is incident from the deflection angle θ direction. The wrong measurement result is obtained. In order to prevent such a situation, when delay addition is used, determination using a threshold value or the like is performed when a peak is detected. However, when threshold determination is performed, if the threshold value is set high, the peak from the actual object may not be detected. Conversely, if the threshold value is set low, the peak not derived from the actual object as described above is detected. There is a fear. On the other hand, when delay multiplication is used, directivity is not good, and as such, it cannot be applied to ultrasonic three-dimensional distance measurement.

  Therefore, in view of the above circumstances, the present invention provides an ultrasonic three-dimensional distance measuring device and an ultrasonic three-dimensional that can accurately measure a three-dimensional position and a three-dimensional shape of an object without performing threshold determination. It is an object to provide a distance measurement method.

  In order to solve the above-mentioned problem, the invention of claim 1 includes an ultrasonic transmission element that transmits ultrasonic waves, and a plurality of ultrasonic reception elements that receive reflected waves generated by reflecting the ultrasonic waves on an object. In the ultrasonic three-dimensional distance measuring device that measures the spatial shape of the object based on the received signal obtained by the ultrasonic receiving element, a delay unit that delays the received signal to generate a delayed signal; and Multiplying means for multiplying a delayed signal and signal strength changing means for setting the signal strength of the received signal or delayed signal to 0 in a portion less than a predetermined value.

  Here, the spatial shape means a three-dimensional position and a three-dimensional shape (hereinafter the same).

  In addition, “0” in “set the signal intensity to 0 at a portion less than a predetermined value” is not only a strict 0, but also a size that can be regarded as substantially 0 in consideration of a signal intensity derived from an object. Including.

  According to the first aspect of the invention, since the directivity of the ultrasonic three-dimensional distance measuring device is improved, the spatial shape of the object can be accurately measured without performing threshold determination (for details, see [Invention BEST MODES FOR IMPLEMENTING]).

  According to a second aspect of the present invention, in the first aspect of the invention, the predetermined value is zero.

  Here, “0” of “predetermined value is set to 0” includes not only exact 0 but also a size that can be regarded as substantially 0 in consideration of signal intensity and the like derived from an object.

  According to the second aspect of the present invention, since the information of the received signal or the delayed signal before the signal intensity is reduced to 0 in the portion less than the predetermined value remains more than when the predetermined value is positive, the measurement accuracy is improved. In addition, the directivity of the ultrasonic three-dimensional distance measuring device can be improved as compared with the case where the predetermined value is negative (for details, refer to [Best Mode for Carrying Out the Invention]).

  In order to solve the above-mentioned problems, the invention of claim 3 includes an ultrasonic transmission element that transmits ultrasonic waves, and a plurality of ultrasonic reception elements that receive reflected waves generated by reflecting the ultrasonic waves on an object. In the ultrasonic three-dimensional distance measuring method for measuring the spatial shape of the object based on the received signal obtained by the ultrasonic receiving element, the delay step of generating a delayed signal by delaying the received signal; A multiplication step of multiplying the delay signal and a signal strength changing step of setting the signal strength of the received signal or the delay signal to 0 in a portion less than a predetermined value are characterized.

  Here, “0” in “set the signal strength to 0 at a portion less than a predetermined value” is not only a strict 0 but also a size that can be regarded as substantially 0 in consideration of the signal strength derived from the object. Also including.

  According to the invention of claim 3, since directivity is improved in the ultrasonic three-dimensional distance measurement method, it is possible to accurately measure the spatial shape of the object without performing threshold determination (for details, see [Invention BEST MODES FOR IMPLEMENTING]).

  According to a fourth aspect of the invention, in the third aspect of the invention, the predetermined value is zero.

  Here, “0” of “predetermined value is set to 0” includes not only exact 0 but also a size that can be regarded as substantially 0 in consideration of signal intensity and the like derived from an object.

  According to the invention of claim 4, since the information of the received signal or the delayed signal before the signal intensity is reduced to 0 in the portion less than the predetermined value remains more than when the predetermined value is positive, the measurement accuracy is improved. In addition, the directivity of the ultrasonic three-dimensional distance measurement method can be improved as compared with the case where the predetermined value is negative (for details, refer to [Best Mode for Carrying Out the Invention]).

  According to the present invention, an ultrasonic three-dimensional distance measuring device and an ultrasonic three-dimensional distance measuring method capable of accurately measuring a three-dimensional position and a three-dimensional shape of an object without performing threshold determination are provided. can do.

  Hereinafter, the best mode for carrying out the present invention will be described.

  FIG. 1 schematically shows the main configuration and signal flow of an ultrasonic three-dimensional distance measuring apparatus according to an embodiment of the present invention.

  The ultrasonic three-dimensional distance measuring apparatus includes an ultrasonic transmitting element (not shown), an ultrasonic receiving element 1, an amplifying means 2, an AD converting means 3, a direct wave erasing means 4, a signal intensity changing means 5, a noise erasing means 6, The delay unit 7, the multiplication unit 8, and the three-dimensional position calculation unit 9 are the main components. The ultrasonic receiving element 1, the amplifying means 2, the AD converting means 3, the direct wave erasing means 4, the signal intensity changing means 5, the noise erasing means 6, and the delay means 7 are each in one set. The number of sets is the same as the number of ultrasonic receiving elements 1.

  In the present embodiment, the direct wave canceling unit 4, the signal strength changing unit 5, the noise canceling unit 6, the delay unit 7, the multiplying unit 8 and the three-dimensional position calculating unit 9 are configured by software, but the present invention is not limited thereto. For example, the direct wave canceling unit 4, the signal strength changing unit 5, the noise canceling unit 6, the delay unit 7 and the multiplying unit 8 may be constituted by circuits.

  The ultrasonic transmission element transmits an ultrasonic wave having a frequency of 40 kHz, for example. The ultrasonic receiving element 1 receives a reflected wave generated by reflecting the ultrasonic wave on an object, and generates a first reception signal S1 (electric signal) based on the reflected wave. The amplifying unit 2 amplifies the first reception signal S1 and generates a second reception signal S2. The AD conversion means 3 performs AD conversion on the second reception signal S2 to generate a third reception signal S3 that is a digital signal. The direct wave canceling unit 4 generates a fourth reception signal S4 in which the signal intensity of the third reception signal S3 before the predetermined time is zero.

  The direct wave is a wave in which the ultrasonic wave transmitted from the ultrasonic transmitting element reaches the ultrasonic receiving element 1 directly (without being reflected). Therefore, since it is irrelevant and unnecessary for the information on the spatial shape of the object, the corresponding signal portion is deleted (the signal intensity is 0). In the present embodiment, it is assumed that the ultrasonic transmission element is arranged near the ultrasonic reception element 1, and the direct wave is received by the ultrasonic reception element 1 earlier than the reflected wave. Thus, the signal strength of the third reception signal S3 before the predetermined time is set to zero. Note that the direct wave canceling means 4 is not necessarily required when direct waves are distinguished by other methods (for example, directions), and the ultrasonic transmission element is not necessarily disposed near the ultrasonic reception element 1. Absent.

  The signal strength changing unit 5 generates a fifth received signal S5 in which the signal strength of the fourth received signal S4 is less than a predetermined value, which is 0 in the present embodiment. This process changes the signal illustrated in FIG. 2A to the signal of FIG. 2B, and is a process called “half-wave rectification”.

  The noise elimination unit 6 generates a sixth reception signal S6 in which the signal intensity of the fifth reception signal S5 is 0 in a portion that is equal to or less than a predetermined positive value. This is so-called noise removal processing. Therefore, the predetermined positive value may be determined in consideration of the magnitude of noise. The delay means 7 generates a plurality of delay signals S7 obtained by delaying one sixth reception signal S6 by a predetermined different delay time. The multiplication means 8 multiplies the delay signal S7 corresponding to the same deflection angle from the plurality of delay means 7 to generate a multiplication signal S8. The three-dimensional position calculation means 9 calculates a three-dimensional position based on the peak appearing in the multiplication signal S8.

  The above is the main configuration of the ultrasonic three-dimensional distance measuring apparatus according to the embodiment of the present invention. In the present embodiment, the three-dimensional position calculated by the three-dimensional position calculation means 9 is added to this main configuration. Based on the above, an imaging means for displaying spatial shape information was added to an image display means such as a monitor. This imaging means displays an XYZ coordinate space on the image display means and displays a three-dimensional position corresponding to the peak appearing in the multiplication signal S8 as a point. Thereby, the spatial shape of the object is displayed on the image display means, and the measurement result by the ultrasonic three-dimensional distance measuring device according to the embodiment of the present invention is obtained.

  In the present embodiment, the XYZ coordinate space is displayed on the image display means, and the three-dimensional position corresponding to the peak that appears in the multiplication signal S8 is displayed as a point. However, the present invention is not limited to this. For example, the numerical value may be simply displayed on the image display means, or the direction of the object is made to correspond to the position on the image display means, and the distance to the object is indicated by shading on the image display means. (For example, the method of Unexamined-Japanese-Patent No. 2005-49303). In addition to image display means and imaging means, the presence of an object (for example, an intruder) is determined in a specific area based on spatial shape information, and a buzzer is notified when the presence determination result is “existence”. Determination means for activating the means can also be added.

  In this embodiment, the amplifier 2, the AD converter 3, the direct wave canceling unit 4, and the noise canceling unit 6 are provided, but these units are not necessarily required. Further, the signal strength changing means 5 processes the fourth received signal S4, but it is not the fourth received signal S4 but any one of the first to third and sixth received signals S1 to 3, 6 or the delay signal S7. One may be processed.

  In order to explain the operation of the present invention, a case where an ultrasonic three-dimensional distance measuring device is constituted by the ultrasonic receiving elements 1, the signal intensity changing means 5, the delay means 7, and the multiplying means 8 having the arrangement shown in FIG. The directivity simulation results are shown in FIG. FIG. 3A shows the result of electronic scanning when the incident angle α of the reflected wave is 0 °. A sharp peak appears only at the position where the deflection angle θ = 0 °, and the directivity is good. That is, when a reflected wave with an incident angle α = 0 ° is incident, a peak is detected only when the deflection angle θ = 0 °, and therefore a correct measurement result can be obtained. Further, FIG. 3B shows the result of electronic scanning when the incident angle α of the reflected wave is other than 0 °, and each of C1, C2, C3, and C4 has an incident angle α = 20 ° of the reflected wave. , 40 °, 60 °, and 80 °. A sharp peak appears only at the deflection angle θ = 20 ° when the incident angle α = 20 °, and only at the deflection angle θ = 40 ° when the incident angle α = 40 °. I can say that.

  Next, the operation of the signal strength changing means 5 will be described. First, for comparison, in order to perform the conventional delay addition process, four ultrasonic receiving elements 1 arranged in the X direction with a center-to-center distance λ / 2 in the coordinate system of FIG. FIG. 4 shows a simulation result of the signal when the ultrasonic three-dimensional distance measuring device is configured by the adding means. It is assumed that the reflected wave is incident along the XZ plane, and the definitions of the incident angle α and the deflection angle θ of the reflected wave are the same as those in FIG. FIG. 4A shows a delay signal obtained by delaying the reception signal by the delay means 7 when the incident angle α = 0 ° of the reflected wave and the deflection angle θ = 60 °, and a delay addition signal obtained by adding the delay signal by the addition means. Is shown in FIG. As shown in FIG. 4B, the delayed addition signal has an amplitude (peak) even when the deflection angle θ = 60 °, even though the incident angle α = 0 °. That is, directivity is not good.

  On the other hand, the ultrasonic three-dimensional distance measurement is performed by the four ultrasonic receiving elements 1, the signal intensity changing means 5, the delay means 7, and the multiplying means 8 that are arranged in the X direction in the coordinate system of FIG. FIG. 5 shows the simulation results of signals when the apparatus is configured. It is assumed that the reflected wave is incident along the XZ plane, and the definitions of the incident angle α and the deflection angle θ of the reflected wave are the same as those in FIG. When the incident angle α = 0 ° and the deflection angle θ = 60 °, a delayed signal obtained by delaying the signal obtained by half-wave rectifying the received signal by the signal strength changing means 5 by the delay means 7 is shown in FIG. FIG. 5B shows a delayed multiplication signal obtained by multiplying the signal by the multiplication means 8. As shown in FIG. 5B, when the incident angle α = 0 °, the delayed multiplication signal has no amplitude (peak) when the deflection angle θ = 60 °, that is, the intensity is 0. And directivity is good. This is because even if one of the delayed signals multiplied at a certain time has a strength of 0, the multiplication result becomes 0. That is, because the received signal is half-wave rectified by the signal strength changing means 5, the portion of the delayed signal having a strength of 0 has increased.

  Based on this principle, it is understood that the signal processing by the signal strength changing means 5 is not limited to the half-wave rectification described above, but may be anything that “makes the signal strength of the signal less than a predetermined value zero”. . For example, the signal shown in FIG. 6B may be generated by setting the signal intensity of the signal having the maximum amplitude a (> 0) illustrated in FIG. 6A to 0 in a portion less than the predetermined value b. In this case, for example, if the predetermined value b is set in consideration of the magnitude of noise, the noise can be removed. This signal processing corresponds to performing signal processing of the signal intensity changing unit 5 and the noise erasing unit 6 at a time in the above embodiment. The case where the predetermined value b = 0 is half-wave rectification of signal processing by the signal intensity changing means 5 of the above embodiment.

  In addition, the signal intensity of the signal illustrated in FIG. 6A is set to 0 at a portion less than the predetermined value b, and the both ends of the portion at the predetermined value b or more are set to 0 with the peak intensity being a. The signal shown in FIG. (C) may be generated. Further, the signal strength of the signal illustrated in FIG. 6A is set to 0 in a portion less than the predetermined value b, and the signal strength is subtracted by a predetermined value b in a portion greater than the predetermined value b and the signal shown in FIG. May be generated.

  FIG. 6 shows a case where the predetermined value b> 0. In this case, since the signal shown in FIGS. 7B to 7D has more signal intensity 0 than the half-wave rectified signal, the signal shown in FIG. The signal has less information than the signal (for example, a weak signal based on a weak reflected wave from the object may have a signal strength of 0 by the signal strength changing means). For this reason, when the predetermined value b> 0, compared to the case of half-wave rectification, the measurement accuracy is lowered. Conversely, in FIG. 6, the predetermined value b <0 may be satisfied. In this case, since the signal shown in FIGS. 5B to 5D has less signal intensity 0 than the half-wave rectified signal, the signal shown in FIG. The information contained in the signal is greater than the signal. However, since the portion of the signal intensity 0 is smaller than that of the half-wave rectified signal, the case where the signal intensity does not become 0 also increases at the deflection angle θ where the reflected wave is not incident when the delay multiplication is performed. That is, the directivity is worse than when delay-multiplying the half-wave rectified signal.

  FIG. 7 schematically shows a state of a measurement experiment using the ultrasonic three-dimensional distance measuring apparatus of the above embodiment. However, devices other than the arranged ultrasonic receiving elements 1 (10) are omitted. Thirty-two ultrasonic receiving elements 1 were used in a rectangular shape and arranged as shown in FIG. One ultrasonic transmitting element was used and arranged below the ultrasonic receiving element 1.

  Two balloons B1 and B2 having the same size are fixedly arranged in front of the ultrasonic receiving element 1. The coordinate system is an XYZ coordinate system, the direction is as shown in FIG. 7, and the origin is the center of the array 10 of the ultrasonic receiving elements 1. The position of the balloon is relative to the center of the balloon, the balloon B1 is in the direction of β = −20 ° and γ = −40 ° from the origin, 70 cm away, and the balloon B2 is β = 0 °, γ = 0 ° from the origin. Direction, 120 cm away. Here, β is an angle with the Z axis when a vector from the origin to the center of the balloon is projected onto the YZ plane, and its positive / negative is the same as the positive / negative of the Y coordinate value of the center of the balloon. γ is an angle formed with the Z axis when a vector from the origin to the center of the balloon is projected onto the XZ plane, and its positive / negative is the same as the positive / negative of the X coordinate value of the center of the balloon. Balloons B1 and B2 have a diameter of 30 cm.

  For comparison, FIG. 9 shows a signal obtained by performing a conventional delay addition process for this measurement experiment. In the above-described embodiment having the configuration shown in FIG. 1, the addition processing is performed by the addition means when the signal strength changing means 5 is not used and the addition means for performing addition processing is used instead of the multiplication means 8. It is a later signal. FIG. 6A shows the case where the balloon B1 exists (β = −20 °, γ = −40 °), and FIG. 5B shows the direction where the balloons B1 and B2 do not exist (β = 12 °, In this case, γ = −48 °. In the case of FIG. 5A, the peak P1 derived from the reflected wave of the balloon B1 appears greatly. On the other hand, in the case of FIG. 5B, a plurality of peaks appear despite the absence of balloons.

  FIG. 10 shows the three-dimensional position corresponding to the peak appearing in the signal subjected to the conventional delay addition process for this measurement experiment as a point on the XYZ coordinate space. FIG. 6A shows a case where the detection of a target peak when calculating a three-dimensional position is performed by determining the threshold value by lowering the threshold value (threshold value 500). FIG. This is a case where the detection of the target peak at the time of calculation is performed with a threshold value increased (threshold 1500). In FIG. 9A, a large number of images appear even though there are no objects other than the balloons B1 and B2. In FIG. 5B, only an image corresponding to the balloon B1 appears. As described above, in the conventional method of calculating the three-dimensional position based on the delayed addition processing signal, the result greatly differs depending on the threshold value in the threshold determination for detecting the target peak when calculating the three-dimensional position.

  On the other hand, FIG. 11 shows a multiplication signal S8 in the above-described embodiment (processing by the signal intensity changing means 5 is half-wave rectification) having the configuration shown in FIG. FIG. 6A shows the case where the balloon B1 exists (β = −20 °, γ = −40 °), and FIG. 5B shows the direction where the balloons B1 and B2 do not exist (β = 12 °, In this case, γ = −48 °. In the case of FIG. 9A, only the peak P2 derived from the reflected wave of the balloon B1 appears. On the other hand, no peak appears in the case of FIG. That is, the result corresponds to the presence or absence of an actual object.

  The three-dimensional position corresponding to the peak that appears in the multiplication signal S8 in the above-described embodiment (processing by the signal intensity changing means 5 is half-wave rectification) of the configuration shown in FIG. This is shown in FIG. Threshold determination is not performed for detection of a target peak when calculating a three-dimensional position. In the figure, the images other than the images corresponding to the balloons B1 and B2 hardly appear (the image on the upper right in the figure is derived from the wall). As described above, in the method of calculating the three-dimensional position based on the multiplication signal S8 of the present application, even when threshold determination is not performed for detection of a target peak when calculating the three-dimensional position, an accurate three-dimensional position is obtained. A position is obtained, and thus accurate spatial shape information of the object is obtained. That is, according to the ultrasonic three-dimensional distance measuring apparatus (method) of the present application, it is possible to accurately measure the spatial shape of an object without performing threshold determination.

  As mentioned above, although embodiment and Example of this invention were described, this invention is not limited to these, A various deformation | transformation is possible if it is in the range of the technical idea of this invention.

It is a figure which shows typically the main structure and signal flow of the ultrasonic three-dimensional distance measuring device which concerns on embodiment of this invention. It is a figure which shows typically the signal before and behind the half wave rectification process by the signal strength change means which concerns on embodiment of this invention, (A) is a signal before a process, (B) is a signal after a process. It is a figure which shows the directivity with respect to the reflected wave of the ultrasonic three-dimensional distance measuring device which concerns on embodiment of this invention, (A) is the reflected wave of incident angle (alpha) = 0 degree, (B) is incident angle (alpha) = 20,40. , 60, and 80 ° reflected waves. It is a figure which shows the signal at the time of performing the conventional delay addition process, (A) is a signal before an addition process after a delay process, (B) is a signal after a delay addition process. FIG. 6 is a diagram illustrating signals when half-wave rectification processing and delay multiplication processing are performed according to an embodiment of the present invention, where (A) is a signal after half-wave rectification and delay processing and before multiplication processing; The signal after wave rectification and delay multiplication processing. It is a figure which shows typically the signal before and behind the process by the signal strength change means which concerns on another embodiment of this invention, (A) is the signal before a process, (B), (C), (D) is after a process. It is about the signal. It is a figure which shows typically the mode of the measurement experiment using the ultrasonic three-dimensional distance measuring device which concerns on the Example of this invention. It is a figure which shows the arrangement | sequence of the ultrasonic receiving element which concerns on the Example of this invention. It is a figure which shows the signal after the conventional delay addition process, and (A) is a case where a target object exists, (B) is a case where a target object does not exist. It is a figure which shows the measurement result using the conventional delay addition process, and (A) is a case where a threshold value is low, (B) is a case where a threshold value is high. It is a figure which shows the signal after the delay multiplication process which concerns on the Example of this invention, (A) is a case where a target object exists, (B) is a case where a target object does not exist. It is a figure which shows the measurement result using the half wave rectification and the delay multiplication process which concern on the Example of this invention. It is an example of arrangement | positioning of an ultrasonic receiving element, (A) is a front view, (B) is a side view. It is a figure which shows the result at the time of performing electronic scanning in the X-axis direction (along the XZ plane) when the incident angle α of the reflected wave is 0 °, and when (A) uses delay addition, (B) shows a case where delay multiplication is used.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ultrasonic receiving element 5 Signal intensity | strength change means 7 Delay means 8 Multiplication means b Predetermined value S1-6 1st-6th received signal S7 Delay signal

Claims (4)

An ultrasonic transmission element that transmits ultrasonic waves and a plurality of ultrasonic reception elements that receive reflected waves generated by reflection of the ultrasonic waves on an object, and a reception signal obtained by the ultrasonic reception element In the ultrasonic three-dimensional distance measuring device that measures the spatial shape of the object based on
Delay means for delaying the received signal to generate a delayed signal; multiplying means for multiplying the delayed signal; signal strength changing means for setting the signal strength of the received signal or the delayed signal to 0 in a portion less than a predetermined value; An ultrasonic three-dimensional distance measuring device characterized by comprising:   The ultrasonic three-dimensional distance measuring apparatus according to claim 1, wherein the predetermined value is zero. An ultrasonic transmission element that transmits ultrasonic waves and a plurality of ultrasonic reception elements that receive reflected waves generated by reflection of the ultrasonic waves on an object, and a reception signal obtained by the ultrasonic reception element In the ultrasonic three-dimensional distance measurement method for measuring the spatial shape of the object based on
A delay step of delaying the received signal to generate a delayed signal; a multiplying step of multiplying the delayed signal; and a signal strength changing step of setting the signal strength of the received signal or the delayed signal to 0 in a portion less than a predetermined value; An ultrasonic three-dimensional distance measuring method characterized by comprising:   The ultrasonic three-dimensional distance measuring method according to claim 3, wherein the predetermined value is zero.

Images