JP2014050589A - Measuring apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a measuring apparatus capable of widely measuring a sound velocity distribution of a bone surface with a simple configuration.SOLUTION: A probe 2 can move in a triaxial direction. A measurement information acquisition part acquires sound velocity at a measurement portion in a cortical bone on the basis of a reradiation signal from the cortical bone. A measurement position derivation part acquires a measurement position on the basis of a position of the probe 2. A measurement information output part outputs the measurement position and measurement information corresponding to the measurement position. The measurement position derivation part includes: a camera 4 for imaging the probe 2, and takes a reference image of the probe 2 at a reference position of the probe 2 and a transmission/reception-time image of the probe 2 at a transmission/reception position where the probe 2 transmits and receives the signal. The measurement position derivation part calculates moving distance of the probe 2 from the reference position to the transmission/reception position on the basis of the reference image and the transmission/reception-time image.

Description

  The present invention mainly relates to a technique for measuring a sound velocity distribution of an object to be measured.

  2. Description of the Related Art A sound speed measuring device that measures the sound speed of a cortical bone by transmitting an ultrasonic signal to the cortical bone and receiving the ultrasonic signal returned from the cortical bone is known. It is known that there is a correlation between the sound speed of the cortical bone and the soundness of the bone, and it can be used for bone diagnosis by measuring the sound speed of the cortical bone.

  Since the sound velocity of the cortical bone varies greatly depending on the measurement site, there may be a case where sufficient information cannot be obtained for bone diagnosis only by measuring the sound velocity at one location. Thus, if the sound velocity distribution can be obtained by measuring the sound velocity at a plurality of measurement sites of the cortical bone, it can be used as information useful for bone diagnosis.

  In this regard, Patent Document 1 discloses a configuration in which a velocity map indicating the distribution of sound velocity in bone is obtained by scanning an ultrasonic probe vertically and horizontally with appropriate intervals. Non-Patent Document 1 discloses an apparatus for measuring the speed of sound at each part of a bone by attaching an ultrasonic signal transmitter / receiver to a C-shaped arm and moving the C-arm by a motor. . However, Patent Document 1 and Non-Patent Document 1 are configurations in which a measurement object is arranged between an ultrasonic transmitter and a receiver and the sound velocity is measured based on the ultrasonic wave transmitted through the measurement object. Therefore, the sound speed on the surface of the measurement object cannot be measured. That is, the measuring devices described in Patent Document 1 and Non-Patent Document 1 cannot measure the sound velocity of cortical bone.

  In this regard, Non-Patent Document 2 discloses a measuring device that can determine the sound velocity distribution on the surface of the femur. A measuring apparatus described in Non-Patent Document 2 is schematically shown in FIG. As shown in FIG. 8, in the measurement apparatus described in Non-Patent Document 2, the transmission vibrator 81 and the reception vibrator 82 are arranged on the same side when viewed from the measured body (femur) 80. The ultrasonic signal transmitted from the transmitting vibrator 81 is configured to be received by the receiving vibrator 82 after propagating on the surface of the measurement object 80. Thereby, the speed of sound on the surface of the measurement object 80 can be obtained based on the ultrasonic signal received by the receiving transducer 82. Further, the measuring device of Non-Patent Document 2 is configured such that the receiving vibrator 82 can be moved by a stepping motor as shown in FIG. In Non-Patent Document 2, the two-dimensional sound velocity distribution (sound velocity map) on the surface of the measurement object (femur) 80 is obtained by moving the receiving transducer 82 at predetermined intervals and repeating the sound velocity measurement.

  Patent Document 2 discloses a measuring device that can measure the cortical bone of the tibia. As shown in FIG. 9, the measuring apparatus of Patent Document 2 includes a transducer array 83 in which a plurality of ultrasonic transducers 82 are arranged. With this configuration, the ultrasonic signal transmitted from the transmission transducer 81 propagates through the surface of the measurement target (tibial cortical bone) 80 and is then received by each transducer 82 of the transducer array 83. Patent Document 2 discloses that the sound speed derived for each transducer set may be mapped on the bone surface line. That is, as shown in FIG. 9, since each transducer set receives an ultrasonic signal through a different path, the transducer set that receives the ultrasonic signal is switched to obtain the sound speed by switching the transducer set. A sound speed distribution (sound speed map) indicating the sound speed of each part on the surface of the measuring body 80 can be obtained.

US Pat. No. 7,537,566 JP 2010-29240 A

'Femur ultrasound (FemUS)-R. Barkmann, S. Dencks, P. Laugier, F. Padilla, K. Brixen, J. Ryg, A. Seekamp, L. Mahlke, A. Bremer, M, Heller, CC Gluer first clinical results on hip fracture discrimination and estimation of femoral BMD '. Osteoporos Int (2010) 21. page 969-976. E. Camus, G. Berger, P. Laugier. 'Cortical Bone Velocity Mapping using Leaky Surface Acoustic Waves'. 1998 IEEE ULTRASONICS SYMPOSIUM. Page 1471-1474.

  The configuration of Non-Patent Document 2 in which the receiving vibrator is moved by a motor has a problem that the apparatus becomes large. In addition, since the actual bone surface is curved, it is considered that both the positions of the transmitting transducer 81 and the receiving transducer 82 need to be controlled three-dimensionally in order to appropriately measure the sound velocity on the bone surface. It is done. However, to realize this, the apparatus becomes complicated and control becomes difficult.

  In this respect, the configuration of Patent Document 2 does not mechanically move the vibrator, so that the measuring apparatus is not mechanically complicated. However, in order to obtain a sound velocity distribution in a wide range of cortical bone with the configuration of Patent Document 2, it is necessary to increase the number of transducers 82 arranged in the transducer array 83, and the transducer array 83 is enlarged. Further, since the actual bone surface is curved, the arrival angle φ of the ultrasonic signal received by the transducer 82 may become large as shown in FIG. Since the vibrator 82 has directivity, if the arrival angle φ is too large, the signal cannot be received properly. For this reason, in the configuration of Patent Document 2, even if the number of transducers 82 is increased, only a portion of the transducers 82 can actually receive signals properly, and the range in which the sound velocity distribution can be obtained is It will be limited.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a measuring apparatus capable of measuring a sound velocity distribution on a bone surface in a wide range with a simple configuration.

Means and effects for solving the problems

  The problems to be solved by the present invention are as described above. Next, means for solving the problems and the effects thereof will be described.

  According to the first aspect of the present invention, the following measuring apparatus is provided. That is, the measurement apparatus includes a probe, a measurement information acquisition unit, a measurement position deriving unit, a measurement information output unit, and an imaging unit. The probe includes a transmission unit that transmits a signal toward the measurement target, and a reception unit that receives a re-radiation signal of the signal from the measurement target, and is movable in at least one axial direction. The measurement information acquisition unit acquires measurement information of the measurement object at a measurement site in the measurement object based on the re-radiation signal. The measurement position deriving unit acquires a measurement position that is the position of the measurement site based on the position of the probe. The measurement information output unit outputs the measurement position and the measurement information corresponding to the measurement position. The imaging unit captures a first image obtained by imaging the probe at a reference position and a second image obtained by imaging the probe at a transmission / reception position where the signal is transmitted / received. Then, the measurement position deriving unit calculates the amount of movement of the probe from the reference position to the transmission / reception position based on the first image and the second image.

  As described above, by configuring the probe to be movable, for example, even when the measured object is curved, the probe can be arranged at an appropriate position to perform measurement. Then, by detecting the amount of movement of the probe based on the images before and after the movement of the probe, the measurement position can be specified without requiring a special sensor or a complicated mechanical configuration. And the distribution of the measurement result in a to-be-measured body can be obtained by outputting the measurement result according to a measurement position.

  The measurement apparatus is preferably configured as follows. That is, the probe includes a marker graphic including feature points. The measurement position deriving unit obtains a pair of feature points whose feature amounts match with the feature points of the first image and the second image. The measurement position deriving unit calculates the amount of movement based on the coordinates of the matched feature points.

  In this way, by capturing an image of the probe when transmission / reception is performed and performing matching with the image of the probe at the reference position, the amount of movement of the probe from the reference position can be accurately derived.

  The above measuring apparatus can also be configured as follows. That is, the probe includes an inertial measurement device. When the measurement position deriving unit cannot appropriately calculate the movement amount based on the image captured by the imaging unit, the measurement position deriving unit calculates the movement amount of the probe from when the movement amount was last calculated based on the image. Derived based on the output of the inertial measurement device.

  Thus, if the inertial measurement device (acceleration sensor, angular velocity sensor, etc.) is built in the probe, the movement amount and the rotation amount of the probe can be detected without providing a sensor or the like outside the probe. And, when the moving speed of the probe is fast, when the image captured by the camera is blurred and the feature points of the image cannot be matched, the output of the inertial measurement device is interpolated to make the moving speed of the probe fast. Even in this case, the movement and rotation of the probe can be detected with high accuracy.

  In the measurement apparatus, it is preferable that the probe is rotatable at least about one axis.

  In this way, if the probe can be rotated, the position of the probe can be set more freely when signals are transmitted and received. For example, even if the measured object is curved, Measurements can be made at various positions and angles. Thereby, the accuracy of measurement can be improved.

  The measurement apparatus is preferably configured as follows. That is, the measurement position deriving unit calculates the amount of rotation of the probe from the reference position to the transmission / reception position based on the first image and the second image in addition to the movement amount.

  Thus, the movement amount and rotation amount of the probe can be detected based on the images before and after the probe movement.

  According to the 2nd viewpoint of this invention, the measuring apparatus of the following structures is provided. That is, the measurement apparatus includes a probe, a measurement information acquisition unit, a measurement position derivation unit, and a measurement information output unit. The probe includes a transmission unit that transmits a signal toward the measurement target, and a reception unit that receives a re-radiation signal of the signal from the measurement target, and is movable in at least one axial direction. The measurement information acquisition unit acquires measurement information of the measurement object at a measurement site in the measurement object based on the re-radiation signal. The measurement position deriving unit acquires a measurement position that is the position of the measurement site based on the position of the probe. The measurement information output unit outputs the measurement position and the measurement information corresponding to the measurement position. The probe includes an inertial measurement device. The measurement position deriving unit calculates a movement amount from a reference position of the probe to a transmission / reception position where the signal is transmitted / received based on an output of the inertial measurement device.

  That is, in the case where the movement amount of the probe can be measured with sufficient accuracy by the inertial measurement device alone, the configuration for imaging the probe by the imaging unit as described above can be omitted.

  The measurement apparatus is preferably configured as follows. That is, the probe can rotate about at least one axis. The measurement position deriving unit calculates a rotation amount of the probe from the reference position to the transmission / reception position based on the output of the inertial measurement device in addition to the movement amount.

  In this way, the amount of movement and the amount of rotation of the probe can be calculated based on the output of the inertial measurement device.

  The measurement apparatus is preferably configured as follows. That is, the probe has an array in which a plurality of receiving units are arranged. The measurement apparatus acquires the measurement information based on a signal received by at least one of the plurality of reception units.

  In other words, depending on the angle of arrival of the signal from the measured object, the receiving unit may not be able to perform proper reception. For example, when there is only one receiving unit, the objects that can be measured are limited. Therefore, by arranging a plurality of receiving units side by side, the possibility that any one of the receiving units can appropriately receive a signal increases, so that the objects that can be measured by the measuring apparatus can be expanded.

  In the above measurement apparatus, the signal may be an ultrasonic signal. In this case, the measurement information acquisition unit acquires the speed of sound of the measurement object, for example. Further, the measurement information acquisition unit may acquire a broadband ultrasonic attenuation coefficient of the measurement object.

  According to this measuring apparatus, it is possible to obtain the distribution of the sound speed and the distribution of the broadband ultrasonic attenuation coefficient in the measurement object.

  In the measurement apparatus, the measurement object may be a cortical bone in a human body.

  According to this measuring apparatus, it is possible to obtain the distribution of the sound velocity and the distribution of the broadband ultrasonic attenuation coefficient in the cortical bone in the human body.

  According to a third aspect of the present invention, there is provided a measurement method for measuring a measured object by a measurement apparatus having a transmitter and a receiver and including a probe that is movable in at least one axial direction. That is, the measurement method includes a transmission step, a reception step, a measurement information acquisition step, a measurement position derivation step, and a measurement information output step. In the transmission step, a signal is transmitted from the transmission unit toward the measurement object. In the receiving step, a re-radiation signal of the signal from the measured object is received by the receiving unit. In the measurement information acquisition step, measurement information of the measurement object at a measurement site in the measurement object is acquired based on the re-radiation signal. In the measurement position deriving step, a measurement position that is the position of the measurement site is acquired based on the position of the probe. In the measurement information output step, the measurement position and the measurement information corresponding to the measurement position are output. The measurement position deriving step captures a first image capturing step of capturing a first image of the probe at a reference position of the probe, and capturing a second image of the probe at a transmission / reception position where the probe transmits / receives the signal. A second imaging step. In the measurement position deriving step, an amount of movement of the probe from the reference position to the transmission / reception position is calculated based on the first image and the second image.

  According to a fourth aspect of the present invention, there is provided a measurement method for measuring an object to be measured by a measurement device having a transmitter, a receiver, and an inertial measurement device, and having a probe movable at least in one axial direction. The That is, the measurement method includes a transmission step, a reception step, a measurement information acquisition step, a measurement position derivation step, and a measurement information output step. In the transmission step, a signal is transmitted from the transmission unit toward the measurement object. In the receiving step, a re-radiation signal of the signal from the measured object is received by the receiving unit. In the measurement information acquisition step, measurement information of the measurement object at a measurement site in the measurement object is acquired based on the re-radiation signal. In the measurement position deriving step, a measurement position that is the position of the measurement site is acquired based on the position of the probe. In the measurement information output step, the measurement position and the measurement information corresponding to the measurement position are output. In the measurement position deriving step, a movement amount from the reference position of the probe to the transmission / reception position where the signal is transmitted / received is calculated based on the output of the inertial measurement device.

1 is a block diagram of an ultrasonic diagnostic apparatus according to an embodiment of the present invention. The flowchart of the measuring method which concerns on this embodiment. The perspective view which shows a mode that ultrasonic wave transmission / reception is performed with a probe. The typical sectional view showing signs that ultrasonic waves are transmitted and received by a probe. The figure which shows the example of the sound speed distribution obtained with the measuring apparatus of this embodiment. The perspective view which shows the modification of this embodiment. The perspective view which shows another modification. The schematic diagram explaining the nonpatent literature 2. FIG. FIG. 9 is a schematic diagram illustrating Patent Document 2. The schematic diagram which points out the problem of directivity in patent document 2. FIG.

  Next, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of an ultrasonic diagnostic apparatus 1 as a measuring apparatus according to the first embodiment of the present invention.

  The ultrasonic diagnostic apparatus 1 according to the present embodiment uses a cortical bone 10 of the tibia in a human body as a measurement target. The ultrasonic diagnostic apparatus 1 of the present embodiment transmits an ultrasonic signal toward the cortical bone 10 of the tibia and measures the sound velocity of the cortical bone 10 based on the ultrasonic signal returned from the cortical bone 10. It is configured.

  As shown in FIG. 1, the ultrasonic diagnostic apparatus 1 includes a probe (ultrasonic transducer) 2, an apparatus main body 3, and a camera 4.

  The probe 2 transmits and receives ultrasonic waves. The probe 2 includes an abutment surface 2 a that abuts on the surface (skin) of the soft tissue 11 at the measurement site, and a transducer array 22. The transducer array 22 includes a plurality of transducers 24 arranged in a line at equal intervals along the contact surface 2a.

In the following description, the direction in which the transducers 24 are arranged in the transducer array 22 is referred to as the x _probe axis direction, and the direction orthogonal to the contact surface 2a is referred to as the y _probe axis direction. A coordinate system defined by the x _probe axis and the y _probe axis is called a probe coordinate system. The position of each transducer 24 in the probe coordinate system is known.

  When an electric signal is given, the vibrator 24 vibrates its surface to generate an ultrasonic wave, and generates and outputs an electric signal when receiving an ultrasonic wave on the surface. That is, each transducer 24 functions as a transmission unit that transmits an ultrasonic signal and a reception unit that receives an ultrasonic signal. The probe 2 is connected to the apparatus main body 3 by a cable, and is configured to be able to transmit and receive signals to and from the apparatus main body 3.

  The probe 2 included in the ultrasonic diagnostic apparatus 1 of the present embodiment is configured so that the measurer can freely move it by hand. That is, the probe 2 has a size and weight that can be moved by hand. The probe 2 is connected to the apparatus main body 3 by a cable, but is not subjected to any other mechanical restraint. As described above, the probe 2 can be moved with three degrees of freedom and can be rotated about the three axes. The measurer can transmit and receive ultrasonic waves by moving the probe 2 to a desired position freehand.

  The camera 4 is a digital camera such as a CCD camera, for example, and is configured to take an image and output data of the image to the apparatus body 3. As the camera 4, a commercially available web camera or the like can be used. The camera 4 is provided for imaging the probe 2 as shown in FIG. In addition, since the distance between the camera 4 and the probe 2 is relatively short in the arrangement of FIG. 3, the camera 4 of the present embodiment is equipped with a lens 17 for macro photography.

  The apparatus body 3 includes a transmission circuit 31, a reception circuit 33, a transmission / reception separation unit 34, and a calculation unit 35.

  The transmission circuit 31 is configured to generate an electrical pulse signal for generating an ultrasonic wave by vibrating the transducers 24 of the transducer array 22 and to apply the electrical pulse signal to the transducers 24. Yes. The center frequency of the electric pulse signal is, for example, about 1 to 10 MHz.

  The vibrator 24 to which the electric pulse is applied vibrates according to the electric pulse signal and generates an ultrasonic wave. The transmission circuit 31 is configured to apply an electrical pulse signal at an arbitrary timing to each of the plurality of transducers 24 of the transducer array 22. Thereby, it is possible to control to transmit ultrasonic waves from a plurality of transducers 24 all at once or at individual timing.

  The receiving circuit 33 receives an electrical signal output when each transducer 24 constituting the transducer array 22 receives an ultrasonic wave, and performs amplification processing, filtering processing, and digital conversion processing on the electrical signal. The digital reception signal which gave etc. is produced | generated, and it is comprised so that it may transmit to the calculating part 35. FIG.

  The transmission / reception separation unit 34 is connected between the transducer array 22 and the transmission circuit 31 and the reception circuit 33. The transmission / reception separating unit 34 prevents an electrical signal (electrical pulse signal) sent from the transmission circuit 31 to the transducer array 22 from flowing directly to the reception circuit 33, and also sends electricity sent from the transducer array 22 to the reception circuit 33. This is to prevent a signal from flowing to the transmission circuit 31 side.

  The calculation unit 35 includes hardware such as a CPU, RAM, and ROM, and a computer program executed by the hardware, and is based on a signal received by each vibrator 24 and an image captured by the camera 4. The sound velocity distribution of the cortical bone 10 is derived. Details of the processing performed by the calculation unit 35 will be described later.

  The sound speed distribution derived by the calculation unit 35 is graphically displayed on the display unit 32, for example. With the ultrasonic diagnostic apparatus 1 configured as described above, the sound velocity distribution of the cortical bone 10 of the tibia can be measured.

  Moreover, when measuring with the ultrasonic diagnostic apparatus 1 of this embodiment, the brace 5 shown in FIG. 3 is utilized. The appliance 5 is configured to be fixed to a patient's shin 15 to be diagnosed by a belt 16 or the like. The camera 4 is fixed to the brace 5. A frame portion 7 into which the probe 2 can be inserted is formed on the appliance 5. The frame portion 7 is formed so that the contact surface 2a of the probe 2 can be brought into contact with the surface (skin surface) of the soft tissue 11 in the vicinity of the tibia by inserting the probe 2 therein. .

  The frame portion 7 is formed slightly larger than the shape of the probe 2. Therefore, the measurer can freely move and rotate the probe 2 to some extent while the probe 2 is inserted into the frame portion 7. This frame portion 7 is for limiting the movement range of the probe 2 relative to the cortical bone 10 and the camera 4. That is, the probe 2 according to the present embodiment is configured so that the measurer can freely move it by hand, so that when the measurer moves the probe 2 greatly, the probe 2 becomes cortical bone. 10 may be inappropriate for the camera 10 or may be out of the shooting range of the camera 4. The measurer can appropriately maintain the position of the probe 2 with respect to the cortical bone 10 and the camera 4 by moving the probe 2 within the range of the frame portion 7.

  Subsequently, a characteristic configuration of the ultrasonic diagnostic apparatus 1 of the present embodiment will be described.

  As described above, the sound velocity of the cortical bone 10 varies greatly depending on the measurement site. Further, since the surface of the cortical bone 10 of the tibia is curved, there is a case where ultrasonic signals cannot be transmitted and received properly unless the position of the probe 2 is adjusted. Therefore, in order to appropriately measure the sound speed of each part of the cortical bone 10, it is preferable to appropriately change the position and angle of the probe 2 in accordance with the shape of the curved cortical bone 10, for example, as shown in FIG. . In the ultrasonic diagnostic apparatus 1 of the present embodiment, the measurer can freely move the probe 2 by hand, so that it is easy to move the probe according to the cortical bone 10 as shown in FIG. .

  However, the conventional ultrasonic diagnostic apparatus does not have means for detecting the position and angle of the probe 2 that can be moved by hand. For this reason, in the conventional ultrasonic diagnostic apparatus, the sound velocity is measured after the probe 2 is fixed at a predetermined position, and the advantage that the probe 2 can be freely moved cannot be utilized.

  Therefore, the ultrasonic diagnostic apparatus 1 of the present embodiment detects the position and angle of the probe 2 with respect to the brace 5 by image recognition by taking an image of the probe 2 with the camera 4 and detecting a feature point of the image. It is configured as follows. By using image recognition for detection of the position and angle of the probe 2, the position and angle of the probe 2 moved freehand can be detected without using a special sensor or the like. Thus, by making it possible to detect the position and angle of the probe 2, it is possible to measure each part of the cortical bone 10 by taking advantage of the fact that the probe 2 can be freely moved.

  Next, a measurement method using the ultrasonic diagnostic apparatus 1 of the present embodiment will be described with reference to the flowchart of FIG.

  First, the measurer fixes the brace 5 to the patient's shin 15 to be diagnosed prior to the sound velocity measurement by the ultrasonic diagnostic apparatus 1 (step S101, brace setting step). As a result, the brace 5 is fixed to the cortical bone 10 of the tibia that is the measurement object. In addition, since the camera 4 is fixed to the brace 5, the camera 4 is also fixed to the cortical bone 10. In addition, the fixing position of the brace 5 is determined in advance, and is fixed to a specific part of the shin 15 regardless of the sex or age of the patient. Thereby, the variation of the measurement site | part for every patient can be suppressed, and a reliable measurement result can be obtained.

  In the following description, the shooting direction of the camera 4 (the direction in which the camera 4 faces) is referred to as the z-axis direction, the direction parallel to the horizontal axis of the image captured by the camera is the x-axis direction, and the direction parallel to the vertical axis of the image Is called the y-axis direction. As described above, since the camera 4 is fixed to the appliance 5, the orthogonal coordinate system defined by the x axis, the y axis, and the z axis is referred to as an appliance coordinate system.

  Subsequently, the measurer inserts the probe 2 into the inside of the frame portion 7 of the appliance 5 and arranges the probe 2 so as to be at a predetermined position and a predetermined angle with respect to the appliance 5. The position and angle of the probe 2 at this time are set as the reference position of the probe 2. In this state, the measurer takes an image of the probe 2 with the camera 4 by performing a predetermined operation (step S102, first imaging step). The image of the probe 2 taken at this time is referred to as a reference image (first image). Since the probe 2 at the reference position is arranged at a predetermined position and a predetermined angle with respect to the appliance 5, the position and angle of the probe 2 at the reference position in the appliance coordinate system are known.

  Subsequently, the measurer holds the probe 2 by hand and moves it to an appropriate position (step S103, probe moving step), and makes the contact surface 2a of the probe 2 contact the surface of the soft tissue 11 (skin surface). The ultrasonic wave is transmitted / received (step S104).

  The transmission / reception of ultrasonic waves will be specifically described as follows. First, the transmitting circuit 31 applies a signal by giving a predetermined phase difference to the plurality of transducers 24, so that an ultrasonic beam obliquely directed from the transducer array 22 toward the cortical bone 10 as shown in FIG. 4. Is transmitted (transmission step). As shown in FIG. 4, when the ultrasonic beam is incident on the surface of the cortical bone 10 at an angle close to the critical angle, the ultrasonic signal propagates near the surface of the cortical bone 10 and is directed again toward the transducer array 22 side. And radiated into the soft tissue 11. As described above, an ultrasonic signal that has been propagated through the cortical bone 10 and then is radiated again into the soft tissue 11 is referred to as a re-radiation signal.

  A re-radiation signal from the cortical bone 10 is received by at least one of the transducers 24 provided in a line (reception step). Depending on the shape of the cortical bone 10 and the posture of the probe 2 with respect to the cortical bone 10, the re-radiation signal may not be properly received by the transducer 24. However, since the ultrasonic diagnostic apparatus 1 of the present embodiment has a large number of transducers 24 arranged side by side, it is highly possible that any of the transducers 24 can appropriately receive the re-radiation signal in the reception process. Therefore, no matter how the probe 2 is moved in the probe moving step (step S103), it is possible to transmit and receive ultrasonic waves almost certainly. However, even if the re-radiation signal cannot be properly received, in this case, the probe 2 may be moved to another location and the transmission process and the reception process may be performed again. The received ultrasonic signal (re-radiation signal) is sent to the calculation unit 35 via the reception circuit 33.

  Further, when the ultrasonic signal is transmitted and received in step S104, the calculation unit 35 captures an image of the probe 2 with the camera 4 (second imaging step). The image taken at this time is referred to as a transmission / reception image (second image). In addition, the position and angle of the probe 2 at this time are referred to as a transmission / reception position.

  Subsequently, the calculation unit 35 acquires measurement information related to the cortical bone 10 based on the re-radiation signal received by the transducer 24 in step S104 (step S106, measurement information acquisition step). Thus, the calculation unit 35 has a function as the measurement information acquisition unit 36. The measurement information acquisition unit 36 of the present embodiment is configured to acquire the sound speed of the cortical bone 10 as the measurement information. In addition, since the method of calculating the sound speed of the cortical bone 10 based on the re-radiation signal from the cortical bone 10 is described in Patent Document 2, for example, detailed description thereof is omitted.

  As described above, the sound speed of the cortical bone 10 varies greatly depending on the site to be measured. However, only by transmitting and receiving an ultrasonic signal once, it is possible to obtain only the sound speed of a part of the cortical bone 10. That is, it can be said that the sound speed acquired in step S106 is the sound speed measured for a part of the cortical bone 10. The part of the cortical bone 10 for which the speed of sound has been acquired in step S106 is referred to as “measurement part”, and the position of the measurement part is referred to as “measurement position”.

  As shown in FIG. 4, the ultrasonic signal incident on the cortical bone 10 is re-radiated toward the probe 2 after propagating through a part of the cortical bone 10. When the sound velocity of the cortical bone 10 is acquired based on the re-radiation signal, a site where the ultrasonic signal propagates through the cortical bone 10 becomes a “measurement site”. The computing unit 35 derives the position (measurement position) of the measurement site based on the ultrasonic signal transmitted and received by the probe 2 (step S105). As described above, the calculation unit 35 has a function as the measurement position deriving unit 30. The measurement position is derived by calculating the propagation route of the ultrasonic signal transmitted and received by the probe 2 using the technique described in Patent Document 2, for example, and the part where the ultrasonic signal propagates in the cortical bone 10 This can be done by obtaining the position (measurement position) of (measurement site).

In step S105, since the measurement position is derived based on the ultrasonic signal transmitted and received by the probe 2, the measurement position expressed in the coordinate system (probe coordinate system (x _probe , y _probe )) based on the probe 2 is acquired. Is done.

  By the way, the probe 2 of this embodiment is comprised so that it can move or rotate freely. As shown in FIG. 4, when the probe 2 is moved or rotated, the probe coordinate system is also moved or rotated. Therefore, when the measurement positions are expressed in the probe coordinate system, it is difficult to compare the plurality of measurement positions in the same coordinate system when the sound speeds of the plurality of measurement sites are measured while moving the probe 2. . For this reason, it is preferable that the sound velocity measurement position can be expressed by a coordinate system independent of the movement or rotation of the probe 2.

  Therefore, the measurement position deriving unit 30 of the present embodiment is configured to coordinate-convert the measurement position expressed in the probe coordinate system into the appliance coordinate system (steps S107 to S111, measurement position deriving step). For this purpose, the measurement position deriving unit 30 is configured to detect the position of the probe 2 with respect to the brace 5 by image recognition based on the image captured by the camera 4.

  Specifically, it is as follows. The measurement position deriving unit 30 detects the feature point of the reference image captured in step S102 and the feature point of the transmission / reception image captured in step S104, and obtains the feature amount of each feature point (step S107, Feature point detection step). As described above, the measurement position deriving unit 30 has a function as the feature point detecting unit 37. As a method of detecting feature points and feature amounts, the SURF method well known in the field of image recognition can be used.

  In the present embodiment, as shown in FIG. 3, a marker graphic 18 with clear contrast and shape is attached to the surface of the probe 2 facing the camera 4. Therefore, the image captured by the camera 4 includes at least a part of the marker graphic 18. Since the marker graphic 18 has clear contrast and shape, the feature point detection unit 37 can easily detect the feature points of the marker graphic 18 included in the reference image and the transmission / reception image captured by the camera 4. Thereby, the detection precision of a feature point and a feature-value can be improved.

  In addition, since the camera 4 of this embodiment is equipped with the lens 17 for macro photography, the captured image has a relatively large distortion (radial distortion). It is preferable to calibrate this distortion in order to accurately perform the feature point matching process described later. Therefore, the measurement position deriving unit 30 corrects the position of the feature point detected in step S106 and removes the influence of radial distortion (step S108, camera correction process).

  Subsequently, the measurement position deriving unit 30 obtains a combination (feature point pair) of feature points having the same feature amount between the reference image and the transmission / reception image based on the feature amount of each feature point obtained in step S107 (step step). S109, matching processing step). As described above, the measurement position deriving unit 30 has a function as the matching processing unit 38.

  Note that the feature point pair obtained as described above may include an incorrect combination. Therefore, the matching processing unit 38 performs processing for removing an incorrect feature point pair. As a method for detecting an incorrect feature point pair, for example, an algorithm such as the RANSAC method or the M-estimator method may be used. However, these algorithms may not converge. Therefore, in this embodiment, an incorrect feature point pair is deleted using a simple threshold without using these algorithms.

  Specifically, it is as follows. Since the present embodiment aims to detect the position and angle of the probe 2 by image recognition, a feature point pair that is not possible as a combination of feature points for the probe 2 may be deleted. In this regard, in the present embodiment, the probe 2 is moved inside the frame portion 7 of the appliance 5, so the range in which the probe 2 moves is limited, and the amount of movement of the feature points on the image is also limited. Therefore, the matching processing unit 38 determines that there is no possible combination of feature points for the probe 2 when the distance between the feature points is greater than a predetermined threshold in a certain feature point pair. Delete feature point pairs.

Next, the measurement position deriving unit 30 derives the geometrical transformation (movement amount and rotation amount) of the probe from the reference position to the transmission / reception position based on the feature point pair obtained as described above (step S110, geometry). Academic transformation derivation process). As described above, the measurement position deriving unit 30 has a function as the geometric transformation deriving unit 39. The geometric transformation parameters to be obtained are the movement amount Δx in the x-axis direction, the movement amount Δy in the y-axis direction, the movement amount Δz in the z-axis direction, the rotation amount θ _x around the x-axis in the orthotic coordinate system, and the y-axis. Six parameters are conceivable: a rotation amount θ _y around the axis and a rotation amount θ _z around the z axis.

By the way, since the ultrasonic diagnostic apparatus 1 according to the present embodiment is configured to detect the movement amount and the rotation amount of the probe 2 based on the image captured by the camera 4, the movement and rotation in the xy plane are compared. Although it can be detected with high accuracy, movement and rotation in a direction orthogonal to the xy plane is considered to have poor detection accuracy. Therefore, the geometric transformation deriving unit 39 of the present embodiment assumes that the probe 2 moves only in the xy plane, and among the geometric transformation parameters, the movement amount Δx, y axis in the x axis direction. Only the three parameters of the direction movement amount Δy and the rotation amount θ _z around the z axis are obtained. In a certain feature point pair, if the coordinate of the feature point on the reference image is (x, y) and the coordinate of the feature point on the transmission / reception image is (x ′, y ′), the geometric transformation of the probe 2 Can be expressed as:

Above parameters [Delta] x, [Delta] y, and theta _z can be determined for each feature point pair. Geometric transformation deriving unit 39 uses the fitting method such as Levenberg-Marquardt method, obtaining a combination of parameter [Delta] x, [Delta] y, and theta _z optimizing the equation (1).

Note that, when parameters are obtained using the fitting method as described above, if an incorrect feature point pair remains, the parameters cannot be accurately derived. Therefore, the geometric transformation derivation unit 39 uses the three parameters Δx, Δy, and θ _z obtained by fitting as described above and the coordinates (x, y) of each feature point on the reference image as mathematical formulas. By substituting into 1, the coordinates (x ′, y ′) of the feature points on the transmission / reception image are calculated. Then, an error between the coordinates calculated as described above and the actual coordinates (x ′, y ′) of the corresponding feature point on the transmission / reception image is obtained. The arithmetic unit 35, the error is large characteristic point pairs by removing and re determined parameters [Delta] x, [Delta] y, and theta _z. By repeating this, geometric transformation deriving unit 39 can be obtained with high [Delta] x, [Delta] y, and theta _z accuracy.

As described above, it is possible to determine the movement amount [Delta] x, [Delta] y, and the rotation amount theta _z from the reference position of the probe 2 to the transmission and reception position. By the way, as described above, the position and angle of the probe 2 in the appliance coordinate system at the reference position are known. Therefore, the measurement position deriving section 30, to the position and angle at the appliance coordinate system of the probe 2 at the reference position, the movement amount [Delta] x, by applying [Delta] y, and the amount of rotation theta _z, of the probe 2 in the receiving position Find the position and angle in the orthotic coordinate system. As described above, the position and angle of the probe 2 (the position and angle of the probe 2 at the transmission / reception position) when the ultrasonic signal is transmitted and received in step S104 can be obtained in the appliance coordinate system.

Now, if the position and angle of the probe 2 when the ultrasonic signal is transmitted and received in step S104 are known in the appliance coordinate system, the coordinate of the probe coordinate system when the ultrasonic signal is transmitted and received can be transformed into the appliance coordinate system. . The measurement position deriving unit 30 converts the measurement position (x _probe , y _probe ) in the probe coordinate system acquired in step S105 into the appliance coordinate system (x, y, z) (step S111). As described above, the measurement position of the sound velocity of the cortical bone 10 can be obtained by the orthosis coordinate system (x, y, z).

  Since the brace 5 is fixed with respect to the cortical bone 10, the brace coordinate system is fixed with respect to the cortical bone 10. From this, it can be said that the orthotic coordinate system is a coordinate system based on the cortical bone 10. Therefore, it can be said that the measurement position can be obtained based on the cortical bone 10 by the measurement position deriving step.

  And the calculating part 35 matches and memorize | stores the value of the sound speed acquired by step S106, and the measurement position in the appliance coordinate system calculated | required by step S111 (step S112).

  The measurer moves the probe 2 as necessary (step S103), transmits and receives ultrasonic waves, and captures an image of the probe 2 (step S104), thereby measuring the speed of sound (step S106). Since the position and angle of the probe 2 can be freely changed, the speed of sound for each part of the cortical bone 10 can be appropriately measured by adjusting the position of the probe 2. And the measurement position in an orthosis coordinate system is calculated | required by the process of step S107 to step S111.

  By repeating the processing from step S103 to step S112, the relationship between the measurement position in the appliance coordinate system and the measured value of the sound velocity at the measurement position can be obtained. The computing unit 35 outputs the relationship between the measurement value of the sound speed and the measurement position of the sound speed in the equipment coordinate system to the display unit 32 as necessary (step S113, measurement information output step). Thus, the calculation unit 35 has a function as the measurement information output unit 41.

  The display unit 32 is configured to appropriately plot and display the relationship between the sound velocity input from the measurement information output unit 41 and the measurement position on a graph. An example of the graph displayed on the display unit 32 is shown in FIG. Since the orthosis coordinate system is a three-dimensional orthogonal coordinate system, the sound speed measured by the measuring apparatus of the present embodiment can be plotted in a three-dimensional space (x, y, z). However, for convenience of illustration, FIG. 5 shows a graph in which the sound velocity is plotted only in the x-axis direction.

  Since the equipment coordinate system is independent of the movement and rotation of the probe 2, the sound speed is measured by appropriately moving and rotating the probe 2, and the relationship between the measurement result of the sound speed and the measurement position in the equipment coordinate system is determined. Plotting can be performed as shown in FIG. Thus, by measuring the sound speed for each part of the cortical bone 10 while appropriately moving the probe 2, the distribution of the sound speed in the cortical bone 10 can be obtained.

  Further, as described above, the brace 5 is fixed at a predetermined position regardless of the age and sex of the patient. Therefore, as shown in FIG. 5, the sound speed measured for the cortical bones of patients with different ages and genders can be plotted and compared in the same orthosis coordinate system. For example, FIG. 5 shows an example in which the results of measuring the speed of sound for cortical bones of three patients with different ages and genders are plotted in one graph. Thereby, the bone diagnosis of a patient can be performed more accurately in consideration of the difference depending on age and sex.

  As described above, the ultrasonic diagnostic apparatus 1 of this embodiment includes the probe 2, the measurement information acquisition unit 36, the measurement position deriving unit 30, the measurement information output unit 41, and the camera 4. Yes. The probe 2 includes a transducer 24 that transmits a signal toward the cortical bone 10 and receives a re-radiation signal of the signal from the cortical bone 10. Further, the probe 2 can be freely moved in the three axis directions. The measurement information acquisition unit 36 acquires the speed of sound at the measurement site in the cortical bone 10 based on the re-radiation signal. The measurement position deriving unit 30 acquires the measurement position based on the position of the probe 2. The measurement information output unit 41 outputs a measurement position and measurement information corresponding to the measurement position. The camera 4 captures a reference image obtained by imaging the probe 2 at the reference position, and a transmission / reception image obtained by imaging the probe 2 at the transmission / reception position where signal transmission / reception is performed. Then, the measurement position deriving unit 30 calculates the amount of movement of the probe 2 from the reference position to the transmission / reception position based on the reference image and the transmission / reception image.

  Thus, by configuring the probe 2 to be movable, for example, even when the cortical bone 10 is curved, the probe 2 can be placed at an appropriate position for measurement. Then, by detecting the movement amount of the probe 2 based on the images before and after the movement of the probe 2, the measurement position can be specified without requiring a special sensor or a complicated mechanical configuration. Then, by outputting the sound speed according to the measurement position, the sound speed distribution in the cortical bone 10 can be obtained.

  Next, a second embodiment of the present invention will be described with reference to FIG. In the description of the present embodiment, the same or similar members as those of the above-described embodiment are denoted by the same reference numerals in the drawings, and the description thereof is omitted.

  In the above-described embodiment, since the feature point is detected by taking an image of the probe 2 with the camera 4, the feature point cannot be matched when the camera 4 cannot properly photograph the probe 2. For example, when the probe 2 moves quickly, the image captured by the camera 4 is blurred, making it difficult to detect feature points.

  Therefore, in the second embodiment, the probe 2 is configured to incorporate an inertial measurement unit (IMU: Internal Measurement Unit) 42. Specifically, the inertial measurement device 42 is an acceleration sensor that can detect acceleration in at least the x-axis direction and the y-axis direction, and an angular velocity sensor that can detect at least an angular velocity around the z-axis. The measurement position deriving unit 30 is configured to detect the amount of movement and the amount of rotation of the probe 2 by integrating the output of the inertial measurement device 42. Thereby, even if it is a case where the probe 2 cannot be image | photographed appropriately with the camera 4, the movement amount and rotation amount of the said probe 2 are detectable.

  However, due to the nature of detecting the amount of movement and the amount of rotation of the probe 2 by integrating the output of the inertial measurement device 42, there is a problem that errors accumulate when the measurement time is long. Therefore, the measurement position deriving unit 30 of the second embodiment is configured to detect the amount of movement and the amount of rotation of the probe 2 by combining the inertial measurement device 42 and the camera 4.

  That is, if the feature point matching can be appropriately performed in step S109, the measurement position deriving unit 30 of the second embodiment performs the probe 2 based on the feature point pair as in the first embodiment. Find the geometric transformation of. In this case, since the output of the inertial measurement device 42 is not used, the error of the inertial measurement device 42 does not become a problem.

  On the other hand, when the matching of the feature points cannot be performed appropriately in step S109 (for example, when the image captured by the camera 4 is blurred), the measurement position deriving unit 30 finally performs the geometric transformation based on the feature point pair. The amount of movement and the amount of rotation of the probe 2 from when it can be derived is obtained based on the output of the inertial measurement device 42. In this case, it is only necessary to integrate the output of the inertial measurement device 42 since the last time the geometric transformation was derived. As a result, the integration period is shortened, resulting in less error accumulation and accurate measurement. It is.

  As described above, when image matching can be appropriately performed (when the movement of the probe 2 is slow), geometric conversion is obtained using an image captured by the camera 4 and image matching is appropriately performed. If this is not possible (for example, when the probe 2 moves fast and the image is blurred), the geometric transformation is obtained using the output of the inertial measurement device 42. As described above, the movement amount and the rotation amount of the probe 2 from the reference position can be derived more appropriately by using the camera 4 and the inertial measurement device in a complementary manner.

  Next, a third embodiment of the present invention will be described with reference to FIG. In the description of the present embodiment, the same or similar members as those of the above-described embodiment are denoted by the same reference numerals in the drawings, and the description thereof is omitted.

  As described above, in the above embodiment, it is assumed that the probe 2 moves and rotates in the xy plane. For this reason, in the said embodiment, distribution of the sound speed in a z-axis direction cannot be calculated | required. However, since the sound speed of the tibia that is the measurement target of the ultrasonic diagnostic apparatus 1 changes in the length direction (z-axis direction in FIG. 3), it is more preferable if the sound speed distribution can be obtained in the z-axis direction. . However, as described above, in image recognition based on video captured by one camera 4, the detection accuracy of movement in the z-axis direction is low.

Therefore, in the third embodiment, in order to accurately derive the amount of movement and the amount of rotation of the probe 2 in the direction orthogonal to the xy plane, two or more cameras 4 for photographing the probe 2 are provided. . The measurement position deriving unit 30 detects the position of the feature point in the z-axis direction based on the triangulation principle based on the images of the probe 2 taken by two or more cameras 4. Thereby, the measurement position deriving unit 30 can accurately derive the movement amount (Δz) of the probe in the z-axis direction, the rotation amount θ _x about the x axis, and the rotation amount θ _y about the y axis. Therefore, according to the configuration of the third embodiment, the sound velocity distribution of the cortical bone 10 can be accurately obtained in three dimensions.

  The preferred embodiment of the present invention has been described above, but the above configuration can be modified as follows, for example.

  In the above-described embodiment, the probe can be freely moved (freehand) by the measurer by hand, but is not necessarily limited thereto. For example, the movement direction or rotation direction of the probe may be limited to a specific direction by providing some kind of movement restriction member. The configuration of the present invention can be applied to any measuring device configured to be able to move the probe in at least one axial direction.

  In the above embodiment, the ultrasonic beam for the cortical bone 10 is transmitted from the transducer array 22, but a dedicated transducer (transmission) for transmitting the beam as in the sound velocity measuring device described in Patent Document 2, for example. Part) may be provided.

  In the above embodiment, the speed of sound is acquired as information on the cortical bone 10, but the information measured by the measuring apparatus of the present invention is not limited to the speed of sound. For example, BUA (Broadband Ultrasonic Attenuation) in the measurement object may be acquired as information about the measurement object. In addition, since the method of measuring BUA is well-known, description is abbreviate | omitted.

  In the above embodiment, the inertial measurement device 42 is used in combination with the camera 4. This is because when the output of the inertial measurement device 42 is integrated, an error is accumulated, so that it is difficult to use it alone. However, if the measurement accuracy of the inertial measurement device 42 is sufficient, the inertial measurement device 42 alone may be used to detect the movement amount and the rotation amount of the probe 2 from the reference position. In this case, the camera 4, the feature point detection unit 37, and the matching processing unit 38 can be omitted.

  The brace 5 is not essential and can be omitted. When the appliance 5 is omitted, the camera 4 may be directly fixed to the patient's shin with a belt or the like.

  It is sufficient that the camera 4 is guaranteed not to move relative to the measurement object (cortical bone 10) during the measurement, and is not necessarily fixed directly to the shin as shown in FIG. There is no need to be.

  In addition, the measuring device of the present invention is not limited to use as a diagnostic device for diagnosing a human body. For example, the measuring device of the present invention can be used in the field of nondestructive inspection. For example, the presence or absence of cracks in the concrete can be determined by obtaining the sound velocity distribution of the concrete with the measuring device of the present invention.

1 Ultrasonic diagnostic equipment (measuring equipment)
2 Probe 4 Camera (imaging part)
10 Cortical bone (object to be measured)
24 vibrator (transmitter, receiver)
30 Measurement position deriving unit 36 Measurement information acquiring unit

Claims (14)

A probe that has a transmitter that transmits a signal toward the device under test, and a receiver that receives a re-radiated signal of the signal from the device under test, and that is movable in at least one axial direction;
Based on the re-radiation signal, a measurement information acquisition unit that acquires measurement information of the measurement object at a measurement site in the measurement object;
A measurement position deriving unit that acquires a measurement position that is the position of the measurement site based on the position of the probe;
A measurement information output unit for outputting the measurement position and the measurement information corresponding to the measurement position;
An imaging unit for imaging the probe;
With
The imaging unit
A first image obtained by imaging the probe at a reference position;
A second image obtained by imaging a probe at a transmission / reception position where the signal is transmitted / received;
Image
The measurement position deriving unit calculates a movement amount of the probe from the reference position to the transmission / reception position based on the first image and the second image. The measuring device according to claim 1,
The probe includes a marker graphic including feature points,
The measurement position deriving unit obtains a pair of feature points whose feature amounts match in the feature points of the first image and the second image, and calculates the movement amount based on the coordinates of the matched feature points. A measuring apparatus characterized by: The measuring apparatus according to claim 1 or 2,
The probe includes an inertial measurement device,
When the measurement position deriving unit cannot appropriately calculate the movement amount based on the image captured by the imaging unit, the movement amount of the probe from when the movement amount was last calculated based on the image, Deriving based on the output of the inertial measurement device. A measuring device according to any one of claims 1 to 3,
The measurement apparatus according to claim 1, wherein the probe is rotatable about at least one axis. The measuring device according to claim 4,
The measurement position deriving unit calculates a rotation amount of the probe from the reference position to the transmission / reception position based on the first image and the second image in addition to the movement amount. . A probe that has a transmitter that transmits a signal toward the device under test, and a receiver that receives a re-radiated signal of the signal from the device under test, and that is movable in at least one axial direction;
Based on the re-radiation signal, a measurement information acquisition unit that acquires measurement information of the measurement object at a measurement site in the measurement object;
A measurement position deriving unit that acquires a measurement position that is the position of the measurement site based on the position of the probe;
A measurement information output unit for outputting the measurement position and the measurement information corresponding to the measurement position;
With
The probe includes an inertial measurement device,
The measurement position deriving unit calculates a movement amount from a reference position of the probe to a transmission / reception position where the signal is transmitted / received based on an output of the inertial measurement apparatus. The measuring device according to claim 6,
The measurement apparatus according to claim 1, wherein the probe is rotatable about at least one axis. The measuring device according to claim 7,
The measurement position deriving unit calculates a rotation amount of the probe from the reference position to the transmission / reception position based on an output of the inertial measurement apparatus in addition to the movement amount. A measuring device according to any one of claims 1 to 8,
The probe has an array in which a plurality of receiving units are arranged side by side,
The measurement apparatus acquires the measurement information based on a signal received by at least one of the plurality of reception units. A measuring device according to any one of claims 1 to 9,
The signal is an ultrasonic signal;
The measurement apparatus is characterized in that the measurement information is a sound velocity of the object to be measured. A measuring device according to any one of claims 1 to 9,
The signal is an ultrasonic signal;
The measurement information is broadband ultrasonic attenuation of the object to be measured. The measurement apparatus according to claim 10 or 11,
The measuring device is a cortical bone in a human body. A measuring method for measuring an object to be measured by a measuring device having a transmitter and a receiver and including a probe movable in at least one axial direction,
A transmission step of transmitting a signal from the transmission unit toward the measurement object;
A receiving step of receiving a re-radiated signal of the signal from the measured object at the receiving unit;
Based on the re-radiation signal, a measurement information acquisition step for acquiring measurement information of the measurement object at a measurement site in the measurement object;
A measurement position deriving step of obtaining a measurement position which is the position of the measurement site based on the position of the probe;
A measurement information output step for outputting the measurement position and the measurement information corresponding to the measurement position;
Including
The measurement position deriving step includes
A first imaging step of imaging a first image of the probe at a reference position of the probe;
A second imaging step of capturing a second image of the probe at a transmission / reception position where the probe transmits / receives the signal;
Including
A measurement method characterized by calculating an amount of movement of the probe from the reference position to the transmission / reception position based on the first image and the second image. A measuring method for measuring an object to be measured by a measuring device having a transmitter, a receiver, and an inertial measuring device, and having a probe movable in at least one axial direction,
A transmission step of transmitting a signal from the transmission unit toward the measurement object;
A receiving step of receiving a re-radiated signal of the signal from the measured object at the receiving unit;
Based on the re-radiation signal, a measurement information acquisition step for acquiring measurement information of the measurement object at a measurement site in the measurement object;
A measurement position deriving step of obtaining a measurement position which is the position of the measurement site based on the position of the probe;
A measurement information output step for outputting the measurement position and the measurement information corresponding to the measurement position;
Including
In the measurement position deriving step,
A measurement method, comprising: calculating a movement amount from a reference position of the probe to a transmission / reception position where the signal is transmitted / received based on an output of the inertial measurement device.

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