JP2009072407A - Pulse wave measuring apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To remove the complicated steps to determine an optimum position of a pulse wave sensor. <P>SOLUTION: A sensor unit 1 is installed on one's wrist. A biological image information including the wrist is obtained with a camera 1B within the sensor unit 1 and the characteristics of the wrist surface are recognized from the image information. The distance of movement of the sensor is calculated from a relationship between wrist characteristic points of the recognized and the optimum sensor position given in advance. A sensor part 1A within the unit is moved by a motor 1C or the like in accordance with the calculated movement distance information. The information of inner artery pressures is obtained by pressing the moved pressure sensor array 11 against his body surface using a pressure cuff 13. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a pulse wave measurement device, and more particularly to a pulse wave measurement device having an arterial position search function based on image recognition.

  When measuring the pulse wave of the measurement subject (patient, etc.) using the pulse wave measurement device, the measured pulse wave includes an extruding pressure wave (ejection wave) of blood flow from the heart and a reflected pressure from the end. A wave (reflected wave) is detected. By measuring the pulse wave including the ejection wave and the reflected wave, the degree of hardening (aging) of the blood vessel of the measurement subject can be known. Therefore, measuring the pulse wave is very important for knowing the health condition of the subject.

  A conventional pulse wave measuring device includes a sensor attached to a measurement site on the wrist radial artery. At the time of measurement, the measurement subject moves the sensor to the optimum measurement position, that is, the position of the artery. Rough alignment is performed by manual operation, but fine adjustment determines the artery position while actually measuring the pulse wave.

  In order to accurately measure the pulse waveform from the radial artery, it is necessary to position the sensor at an optimal position directly above the radial artery. Further, when the radial artery is viewed in the longitudinal direction, the intra-arterial pressure corresponding to the pulse wave can be measured with high accuracy at the portion that is most prominent on the surface of the living body.

In the conventional technique, as in Patent Document 1 and Patent Document 2, the position of the radial artery is searched by palpation with a human finger, and measurement is performed by positioning the sensor immediately above. Further, when the sensor is deviated from the optimum position, the position of the sensor is corrected by the manual power of Patent Document 1 or the external power of Patent Document 3, thereby positioning the sensor directly above the radial artery. In Patent Document 4, the position of the radial artery is searched by a technique using light, and the sensor is positioned immediately above the radial artery.
JP 2003-325463 A Japanese Patent Publication No. 6-510919 Japanese Utility Model Publication No. 01-126205 Japanese Patent Laid-Open No. 11-70087

  However, in Patent Document 1 and Patent Document 2, the optimal position is unclear because it depends on a human sense of palpation with a finger. In addition, there is an optimum position in the longitudinal direction of the radial artery, and in the search of palpation using this finger with the optimum position, the search results vary.

  Further, with the technique of Patent Document 4, it is until the search for an artery, and the optimum position in the longitudinal direction of the artery cannot be searched. In addition, a measuring element or a circuit for specifying the position of the artery using light is required. Also, light is easily disturbed and it is difficult to obtain a certain measurement accuracy.

  SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a pulse wave measuring device that eliminates the complexity of positioning for pulse wave measurement of a pulse wave sensor.

  According to an aspect of the present invention, a pulse wave measuring device includes: a sensor unit having a pressure sensor that is pressed against the surface of a living body; and a photographing unit that captures an image of the surface of the living body pressed by the pressure sensor and outputs image data. A sensor unit that can move on the surface of the living body, a feature detection unit that detects predetermined feature data indicating a predetermined feature of the living body surface corresponding to the artery, from image data, and detection of the predetermined feature data by the feature detection unit A movement amount detection unit that detects a movement amount by which the sensor unit should move based on the position and a position registered in advance corresponding to the predetermined feature data;

  Preferably, the sensor unit further includes a sensor moving unit for moving the sensor unit on the surface of the living body based on the given drive signal, and the pulse wave measuring device further includes a movement amount detected by the movement amount detecting unit. A drive signal generator for generating and outputting a drive signal based on the above.

  Preferably, the sensor moving unit includes a motor that rotates in accordance with the drive signal, and the sensor unit moves in conjunction with the rotating operation.

  Preferably, the sensor moving unit includes a telescopic tube that is airtightly attached around the sensor unit and expands and contracts according to the amount of gas inside the sensor unit, and an adjustment unit that adjusts the gas amount in the telescopic tube according to the drive signal, Moves in conjunction with expansion and contraction.

  Preferably, the sensor unit can be slid in the arrangement direction of the pressure sensor array, and the pulse wave measuring device starts from the pressure sensor at one end of the pressure sensor array pressed by the pressing unit, and the other end. The graph creation unit creates graph data that continuously plots the pressure data output by each pressure sensor according to the order of the arrangement of the pressure sensors in the array, and the graph created by the graph creation unit A display control unit configured to display a graph based on the data on a display unit prepared in advance.

  Preferably, the display control unit detects a position in the arrangement of the pressure sensors located on the artery according to the distribution of the pulse pressure indicated by the graph data created by the graph creating unit, and based on the detected position, the pressure sensor Direction indication data indicating the direction in which the array should slide is displayed on the display unit.

  Preferably, the pressure sensor includes a pressure sensor array in which a surface on which a plurality of pressure sensor elements are arranged is pressed on an artery so that the arrangement direction of the pressure sensor elements intersects the artery, and the pressure sensor array A pulse wave measuring device that presses the surface onto the artery, and the pulse wave measuring device is based on the pulse wave information detected by each of the pressure sensor elements of the pressure sensor array, and the position of the artery and the central pressure sensor in the array A position detection unit that detects a difference from the current position, and a sensor movement amount detection unit that detects a movement amount based on the detected difference.

Preferably, the movement amount indicates a two-dimensional movement amount.
Preferably, the movement amount indicates an amount of movement in a direction in which the first axis intersecting the artery extends.

  Preferably, the movement amount indicates an amount of movement in a direction in which a second axis that intersects the first axis extends.

  According to the present invention, after a user wears a sensor unit that can move on the surface of a living body, a feature of the surface of the living body on an artery that is a pulse wave measurement site is detected from a captured image of the worn site. Then, the sensor unit can be moved to the optimum position by detecting the movement amount to the artery position that is the optimum position for pulse wave measurement based on the detected feature.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same reference numerals indicate the same or corresponding parts, and description thereof will not be repeated.

  In this embodiment, based on the feature points of the living body detected by image recognition, the optimal position that is the measurement site of the living body for measuring the pulse wave of the radial artery is detected, and the measurement site of the detected optimal position is Press the sensor for pulse wave detection. Thereby, based on the output of the sensor, the pulse wave indicated by the internal pressure fluctuation information of the radial artery is measured.

  1 and 2 show a hardware configuration of the pulse wave measurement device according to the present embodiment. FIG. 3 shows the connection relationship between each part including the sensor unit and the fixed base. FIG. 4 shows a state where the sensor unit is mounted on a living body. In the present embodiment, the pulse wave measurement device is configured integrally with the blood pressure measurement device, but may be configured independently.

  Referring to FIGS. 3 and 4, the pulse wave measuring device detects the pulse wave in the radial artery of the wrist, the sensor unit 1 is mounted on the wrist surface of the pulse wave measurement site, and the wrist for pulse wave detection. And a display unit 3 for executing various processes including calculations for pulse wave detection and blood pressure measurement.

  The fixed base 2 contains a fixed base unit 7. The fixed base unit 7 and the sensor unit 1 are connected via a communication cable 5 and an air pipe 6. The cuff 52 attached to the blood pressure measurement site and the display unit 3 are connected via an air tube 53. Here, the fixed base unit 7 and the display unit 3 are connected via a USB (Universal Serial Bus) cable 4 for communication, but may be connected wirelessly.

  When the pulse wave is detected, as shown in FIG. 4, the user places the wrist unit at a predetermined position on the fixed base 2 and the sensor unit 1 is positioned at the radial artery of the wrist (specified by the broken line in FIG. 4). The sensor unit 1 and the fixing base 2 are tightened via the belt 8 in this state, and the sensor unit 1 on the wrist is stopped so as not to be displaced. As the measurement mode, only three types of measurement are assumed: only pulse wave measurement using the sensor unit 1, only blood pressure measurement using the cuff 52, or both measurements.

  The sensor unit 1 for detecting a pulse wave is attached to the wrist. A cuff 52 for blood pressure measurement is wound (mounted) on the upper arm. The manner of mounting is as follows. For example, the pulse wave and blood pressure may be detected simultaneously on the left and right arms, such as mounting the sensor unit 1 on the left arm and mounting the cuff 52 on the right arm. Alternatively, as shown in FIG. 4, the sensor unit 1 and the cuff 52 may be attached to the same arm, and blood pressure may be measured following the detection of the pulse wave.

  Referring to FIG. 1, sensor unit 1 includes a sensor unit 1A for detecting an intra-arterial pressure, and a motor unit 1C for moving sensor unit 1A. The sensor unit 1A includes a pressure sensor array 11 in which a plurality of pressure sensors are arranged, and a multiplexer 12 that selectively derives a voltage signal corresponding to the pulse pressure detected by each of the plurality of pressure sensors in the pressure sensor array 11. , A pressure cuff 13 including an air bag that is pressurized to adjust the pressure sensor array 11 onto the wrist, and a camera 1B.

  The camera 1B images the measurement site where the pressure sensor array 11 of the sensor unit 1A is pressed and the wrist surface around it, and outputs image data indicating an image of the wrist surface. The camera 1B is a CCD (Charged Coupled Device) camera, and shoots using external light that enters from the opening of the housing of the sensor unit 1 formed in advance to press the pressure sensor array 11 against the wrist surface. Assume that you can. An auxiliary light source such as an LED (Light Emitting Diode) may be provided in the sensor unit 1 or the sensor unit 1A for illumination light for photographing.

  The pressure sensor array 11 includes a plurality of diaphragms for detecting a pulse pressure and a pressure sensor including a resistance bridge circuit arranged in one direction on a pressing surface 40 described later of a semiconductor chip made of single crystal silicon or the like.

  The fixed base unit 7 includes a pressurizing pump 14 for pressurizing an internal pressure (hereinafter referred to as cuff pressure) of a pressing cuff (air bag) 13, a negative pressure pump 15 for depressurizing, a pressurizing pump 14 and a negative pressure pump 15. A switching valve 16 for selectively connecting one of the air pipe 6 to the air pipe 6, a control circuit 17 for controlling them, a communication circuit 18 to which the USB cable 4 is connected, and an output derived from the sensor unit 1 An A / D (Analog / Digital) converter 191 for converting a signal into digital data, and a D / A (Digital / Analog) for converting a digital drive signal to be applied to the motor unit 1C into an analog signal and outputting the analog signal A converter 192 is included.

  The display unit 3 includes a CPU (Central Processing Unit) 20 that executes various processes including calculations to centrally control the pulse wave measuring device, and a ROM (Read that stores data and programs for controlling the pulse wave measuring device. Only Memory (Random Access Memory) 21 and RAM (Random Access Memory) 22, an operation unit 23 which is provided to be operated from the outside and is operated to input various information, and various information such as pulse wave detection results and blood pressure measurement results are externally provided. A display 24 comprising an LCD (Liquid Crystal Display) for output, an external I / F (Interface) 41 to which a CD-ROM (Compact Disk Read Only Memory) 42 is detachably mounted, and measures the current time Communication circuit 7 for connecting the CPU 43 to the timer 43, the blood pressure measurement unit 50, and the blood pressure measurement unit 50, which are output as time data. Has a fixing base unit 7 and CPU20 and communication I / F for connecting the communication (Interface) 72 and the measurement result printing part 10 for information prints, such as. The blood pressure measurement unit 50 connects a cuff 52 attached to the upper arm via an air tube 53.

  Here, the fixed base unit 7 and the display unit 3 of the fixed base 2 are provided separately, but a configuration in which both functions are built in the fixed base 2 may be employed. In the case of being built in, the operation unit 23 and the display 24 are attached to the case of the fixed base 2 so that the operation unit 23 and the display 24 can be operated from the outside or the display content can be confirmed from the outside.

  Referring to FIG. 3, the operation unit 23 of the display unit 3 is a switch 231 that is pressed to instruct the start of measurement, a switch 232 that is operated to instruct the end (stop) of measurement, and an output changeover. Switch 233 operated to instruct, displayed on the screen of the display 24, or displayed on the screen of the display 24, the switch 234 operated to switch the range of the pulse wave waveform printed by the printing unit 10. A switch group 235 operated to scroll the waveform of the pulse wave to be operated, and a group of switches operated to instruct selection of information or determination of operation content by moving a cursor (not shown) on the screen of the display 24. 236 and the waveform of the pulse wave output together with the waveform of each pulse wave on the screen of the display 24 or on the paper surface of the printing unit 10. In order to indicate a value to be output, for example, an AI value, a TR (Traveling time to Reflected wave) value which is a known index indicating pulse wave velocity related information, and a SBP2 (second Systolic Blood Pressure) value indicating a central blood pressure estimated value Switches 237, 238, and 239, and a switch 240 that is operated to instruct the printing unit 10 to print information.

  In the present embodiment, the CPU 20 can calculate the AI value, the TR value, and the SBP2 value according to a program stored in advance in the ROM 21 based on the detected pulse wave.

  FIG. 2 shows the configuration of the blood pressure measurement unit 50 and its related parts. Referring to FIG. 2, blood pressure measurement unit 50 has a pressure sensor 54 whose capacity changes depending on the pressure in air bag 51 built in cuff 52 (hereinafter referred to as “cuff pressure”), and the capacitance value of pressure sensor 54. An oscillation circuit 55 that outputs a signal having a corresponding oscillation frequency to the communication circuit 71 via the I / F 60, a pump 56 and a valve 58 for adjusting the cuff pressure level, a pump drive circuit 57 that drives the pump 56, and a valve The valve drive circuit 59 for adjusting the opening / closing degree of 58 is provided. The air bladder 51, the pressure sensor 54, the pump 56 and the valve 58 are connected via an air pipe 53. The I / F 60 converts a signal obtained from the oscillation circuit 15 into a pressure signal (a pressure pulse wave signal indicating a change in arterial volume) and outputs the pressure signal to the communication circuit 71.

  5A to 5C show the configuration of the sensor unit 1A. FIG. 5C shows a schematic cross-sectional structure of the sensor unit 1A in the sensor unit 1 of FIG. 5A in the direction crossing the wrist when the wrist is worn. When the cuff pressure of the pressing cuff 13 of FIG. 5C is adjusted by the pressurizing pump 14 and the negative pressure pump 15, the pressure sensor array 11 attached via a block molded by ceramic or resin is shown in FIG. C) freely moves in the direction of the arrow 25 shown by the amount corresponding to the cuff pressure level. When the pressure sensor array 11 moves downward in the direction of the arrow 25, the pressure sensor array 11 protrudes from an opening provided in advance in the sensor unit 1 and is pressed against the wrist surface.

  As shown in FIGS. 5B and 5C, the arrangement direction of the pressure sensors 26 which are a plurality of sensor elements of the pressure sensor array 11 is substantially orthogonal to the radial artery when the sensor unit 1 is attached to the wrist. Corresponding to the (crossing) direction, the array length is at least longer than the radial artery diameter. When each of the pressure sensors 26 is pressed by the cuff pressure of the pressing cuff 13, pressure information that is a pressure vibration wave (pulse pressure) generated from the radial artery and transmitted to the surface of the living body is output as a voltage signal. For example, 40 pressure sensors 26 are arranged on the pressing surface 40 having a predetermined size (5.5 mm × 8.8 mm).

  The sensor unit 1A is freely movable in the sensor unit 1 by the sensor unit 1C, and one of the movement directions corresponds to the arrangement direction of the pressure sensors 26 of the pressure sensor array 11.

  FIG. 6 shows a cut surface along the line VI-VI in FIG. In FIG. 6, since the cuff pressure of the pressure cuff 13 is sufficiently reduced by the negative pressure pump 15 (because it has a pressure level sufficiently lower than the atmospheric pressure), the pressure sensor array 11 is accommodated in the housing of the sensor unit 1. It is in contact with the wrist surface.

  In FIG. 6, the camera unit 1 </ b> B in the sensor unit 1 </ b> A is fixedly attached at a position where the pressure sensor array 11 is pressed and its periphery is an imaging area. Details of the motor unit 1C including a drive mechanism including a motor for moving the sensor unit 1A in the sensor unit 1 will be described later.

  In the present embodiment, at the time of measuring the pulse wave, a tonogram indicating the distribution of the pulse pressure detected by the pressure sensor array 11 is displayed via the display 24 as described later. Accordingly, the direction in which the solid matter of the tendon 29 or the radial artery 27 is located can be notified to the user by the tonogram.

  FIG. 7 shows a functional configuration of the pulse wave measurement device according to the present embodiment. Referring to FIG. 7, the pulse wave measurement device includes a control unit 400 corresponding to the CPU 20, a storage unit 401 corresponding to the ROM 21 and the RAM 22 for storing various information, a communication control unit 402 corresponding to the communication I / F 72, And a storage control unit 403 for controlling access to the storage unit 401.

  Furthermore, the pulse wave measuring device includes an image processing unit 404 for processing image data captured by the camera 1B, a display processing unit 405 for controlling display of information on the display 24, and image data by the image processing unit 404. Based on the processing result, the position detection unit 406 for detecting the position of the sensor unit 1A, and the movement distance detection for detecting the distance and direction for moving the sensor unit 1A based on the detection result of the position detection unit 406 And a drive signal generation unit 408 that generates a signal for driving the motor unit 1B based on the detection results of the unit 407 and the movement distance detection unit 407.

  Furthermore, the pulse wave measurement device includes a blood pressure measurement unit 409 for controlling blood pressure measurement by the blood pressure measurement unit 50, a pulse wave processing unit 410 for processing a pulse wave signal detected by the sensor unit 1A, and pulse wave processing. A tonogram creation unit 411 that creates tonogram data based on the processing result of the unit 410 is provided.

  The image processing unit 404 includes a feature extraction unit 412 for detecting (extracting) feature data indicating a predetermined feature from input image data. The feature extraction unit 412 includes a pattern matching unit 413 that performs pattern matching between the input image data and image data registered in advance in the storage unit 401 and detects features based on the result of pattern matching.

  The blood pressure measurement unit 409 includes a blood pressure calculation unit 414 that calculates blood pressure based on the pressure signal input from the blood pressure measurement unit 50.

  FIG. 8 shows an example of information registered in the storage unit 401 shown in FIG. Referring to FIG. 8, storage unit 401 stores blood pressure data 500 indicating the calculation result by blood pressure calculation unit 414, tonogram data 501 created by tonogram creation unit 411, and pulse wave information detected by pulse wave processing unit 410. 502, feature image data 503, optimum position data 504, and a table 507 are stored. The contents of the table 507 will be described later.

  The feature image data 503 is image data stored in advance indicating a predetermined feature of the skin surface of the pulse wave measurement site. Details of the predetermined feature will be described later.

  The optimum position data 504 includes feature data 505 indicating a plurality of types of features on the skin surface of the pulse wave measurement site, and position data 506 corresponding to the various types of feature data 505. The position data 506 indicates the position information of the feature indicated by the corresponding feature data 505 in the image photographed by the motor unit 1C when the sensor unit 1A is located at the optimum position for pulse wave detection. . It is assumed that the optimum position data 504 is measured in advance through experiments or the like and stored in the storage unit 401.

  Here, in order to simplify the description, the image data output from the camera 1B indicates a rectangular image. The rectangular image corresponds to a two-dimensional coordinate plane defined by the orthogonal X axis and Y axis, and the position data 506 indicates the position on the coordinate plane by the value of coordinates (X, Y).

  9 and 10 show a mechanism for moving the sensor unit 1A using the motor unit 1C according to the present embodiment. The mechanism shown in FIG. 9 utilizes the driving force transmission mechanism disclosed in Japanese Utility Model Laid-Open No. 1-126205. The moving mechanism of the sensor unit 1A will be described with reference to FIG. 6, FIG. 9, and FIG.

  FIG. 10 is a schematic cross-sectional view of the sensor unit 1 as viewed from above. In the present embodiment, assuming that the direction in which the X axis substantially orthogonal to the radial artery 27 extends is the X direction, and the direction in which the Y axis orthogonal to the X axis extends is the Y direction, the sensor unit 1A It is movable. In FIG. 10, an X-axis direction drive unit 370 and a Y-axis direction drive unit 371 are provided in the sensor unit 1 so that the sensor unit 1A can move in the X and Y directions. The X-axis direction drive unit 370 and the Y-axis direction drive unit 371 include motors 350 and 360 constituting the motor unit 1C, respectively. FIG. 9 shows a drive mechanism of the X-axis direction drive unit 370. Since the mechanisms for driving the X-axis direction drive unit 370 and the Y-axis direction drive unit 371 are the same, here, the X-axis direction drive unit 370 will be described as a representative, and the Y-axis direction drive unit 371 will be described. The explanation is omitted. Each of the X and Y directions indicating the direction in which the sensor unit 1A moves corresponds to each of the extending directions of the X axis and the Y axis that define the above-described two-dimensional coordinate plane of the image.

  Motors 350 and 360 are stepping motors, for example, and are controlled by a rotation angle and a rotation direction instructed by a drive signal that is a pulsed current signal input via D / A converter 192. When the specified angle is rotated, the sensor unit 1A moves in a distance corresponding to the rotation angle in the X direction or the Y direction in conjunction with the rotation. In addition, the rotation direction instructed includes normal rotation and reverse rotation. When the rotation is normal, the sensor unit 1A moves in a predetermined direction in which the X axis or the Y axis extends. Move in the opposite direction.

  With reference to FIGS. 6 and 9, a pair of attachment portions 322 and 324 having a plate shape are predetermined between the side walls 318 and 320 facing each other in the width direction at the middle portion in the longitudinal direction in the sensor unit 1. They are integrally provided in a parallel state at a distance. A feed screw 330 is supported between the attachment portion 322 and the side wall 316 opposed thereto in a direction substantially orthogonal to the radial artery 27 so as to be rotatable about the axis at both ends thereof. 1A is attached.

  The sensor unit 1A includes a movable member 336 provided with a protruding portion 334 at the center of the surface opposite to the pressure sensor array 11 and screwed to the feed screw 330 at the protruding portion 334. Further, the press cuff 13 can project from the opening end of the movable member 336 toward the body surface so as to be relatively movable via the diaphragm 338. In the sensor unit 1A, spaces 342 and 338 are formed by a movable member 336 and a diaphragm 338. In these spaces 342 and 338, the camera 1B displays a measurement site where the pressure sensor array 11 is pressed and a region around it. It is fixed to the movable member 336 so that it can be photographed.

  The sensor unit 1A has a motor 350 corresponding to the motor unit 1C. A reduction gear device 354 formed by combining a plurality of gears is provided between the mounting portions 322 and 324, and the output shaft 352 of the motor 350 and the right end portion in the drawing of the feed screw 330 are provided by the reduction gear device 354. Are operatively connected. As a result, the rotational driving force of the motor 350 is transmitted to the feed screw 330 via the reduction gear device 354. By such a rotational driving force transmission mechanism, the movable member 336 screwed to the feed screw 330 moves freely in the X direction substantially orthogonal to the radial artery 27 in conjunction with the rotation of the motor 350.

  The same mechanism and operation as described above are applied to the Y-axis direction drive unit 371, and the sensor unit 1B freely moves in the Y direction in conjunction with the rotation of the motor 360 according to the drive signal.

  FIG. 11 and FIG. 12 show a processing procedure for arterial position search in image recognition in the pulse wave measurement device according to the present embodiment. This flowchart is stored in advance in the ROM 21 as a program, and the function is realized by the CPU 20 reading and executing each instruction of the program.

  As shown in FIG. 4, the user attaches the sensor unit 1 to the left wrist and fixes it with the belt 8 (step S3). At this time, it is assumed that the user fixes the sensor unit 1 so as to be positioned approximately on the radial artery 27 by palpation. When the mounting is completed, the user presses the switch 231 (YES in step S5), and the process proceeds to the next process (step S7). If switch 231 is not operated (NO in step S5), steps S3 and S5 are repeated until switch 231 is operated. Here, the operation of the switch 231 is used as an instruction to start processing. However, a sensor (not shown) that detects attachment of the belt 8 may be provided, and processing may be started based on the detection result of the sensor.

  In the process of step S7, the position of the radial artery 27 is searched. The specific contents of this process are shown in FIG.

  Referring to FIG. 12, when an operation signal for switch 231 is input, control unit 400 provides a shooting instruction signal to camera 1B via communication control unit 402. The camera 1B to which the instruction signal is given performs a photographing operation and outputs image data obtained by photographing. The output image data is given to the image processing unit 404 via the communication control unit 402 (step T3).

  The image processing unit 404 converts the input image data into a grayscale image, and provides the converted image data to the feature extraction unit 412. The feature extraction unit 412 divides the input image data into a plurality of regions, and the image data for each region and the data indicating each feature amount stored in the feature image data 503 of the storage unit 401 are obtained. Match. This collation is a process for extracting (detecting) the feature of the skin surface on the radial artery 27 from the input image data, and is performed using the pattern matching unit 413 (step T5).

  As a result of pattern matching, when it is detected that the image data of the region matches any one of the feature image data 503, the position detection unit 406 based on the feature image data 503 in which the match is detected, The position data 504 is searched, and the position data 506 corresponding to the feature data 505 that matches the feature image data 503 is read. The read position data 506 is given to the movement distance detection unit 407. The movement distance detection unit 407 detects the distance and direction to which the sensor unit 1A should move (step T7).

  The detected movement distance and direction are given to the drive signal generation unit 408 (step T9). The drive signal generation unit 408 generates a drive signal to be supplied to the motor unit 1C from the sensor unit 1A based on the given moving distance and direction, and outputs the drive signal to the motor unit 1C via the communication control unit 402. As a result, the motor unit 1C rotates in accordance with the input drive signal, so that the sensor unit 1A starts moving in conjunction with the rotation of the motor (step S9). When the sensor unit 1A is moved, the pressure cuff 13 is sufficiently depressurized by the negative pressure pump 15, so that the pressure sensor array 11 is sufficiently separated from the surface of the living body.

  When detecting that the rotation of the motor unit 1C has stopped and the movement has stopped, the control unit 400 controls the pressurization pump 14 to press the pressure sensor array 11 against the living body (step S11). When the pressure sensor array 11 is pressed against the living body, a pulse wave signal is detected by the pressure sensor array 11, and the detected pulse wave signal is given to the pulse wave processing unit 410. The pulse wave processing unit 410 provides the tonogram creation unit 411 with data extracted in time series for each pressure sensor 26 based on the pulse wave signal provided.

  The tonogram creation unit 411 creates tonogram data 501 indicating a tonogram based on the given pulse wave signal data (step S13). Here, as shown in the graph of FIG. 18 described later, the peak value of the pulse pressure signal indicated by the tonogram data 501 corresponds to the output from the pressure sensor array 26 located on the radial artery motion 27 in the pressure sensor array 11. . Therefore, in step S13, the position of the radial artery 27 can be detected by creating the tonogram data 501.

  Next, the tonogram creation unit 411 stores the created tonogram data 501 in the storage unit 401 and gives it to the display processing unit 405. The display processing unit 405 displays a tonogram based on the tonogram data 501 on the display 24 (step S15).

  Next, the pulse wave processing unit 410 detects whether or not there is a difference (deviation) between the radial artery position and the position of the pressure sensor 26 located at the center of the pressure sensor array 11 based on the generated tonogram data 501. If it is determined that the pressure sensor 26 located at the center of the pressure sensor array 11 is located on the radial artery based on the detection result (YES in S17), the control unit 400 ends the positioning, and the pulse wave processing unit A pulse wave measurement is instructed to 410 (step S25). Subsequently, a pulse wave measurement process is performed by the pulse wave processing unit 410 (step S27). In the pulse wave measurement process, of the pressure signals output from the pressure sensors 26 of the pressure sensor array 11 pressed against the measurement site, the pressure sensor 26 having the highest output level (that is, the pressure sensor positioned on the radial artery 27). The detection signals from 26) are input in time series and displayed on the display 24.

  On the other hand, if it is determined that the central sensor 26 of the pressure sensor array 11 is not located on the radial artery 27 (NO in step S17), the movement distance detection unit 407 reads the tonogram data read from the storage unit 401. Based on 501, the movement amount of the sensor unit 1 </ b> A is detected (step S <b> 19). Subsequently, the negative pressure pump 15 is driven to separate the pressure sensor array 11 from the living body (step S21). Subsequently, the sensor unit 1A is moved via the motor unit 1C based on the movement amount detected in step S19 (step S23). When the movement is completed, the processing after step S11 is repeated in the same manner.

  Thus, according to the processing of FIG. 11, in order to optimally position the sensor unit 1A for pulse wave measurement, the sensor unit 1A is manually positioned in step S3 (this is referred to as a first positioning step). Subsequently, positioning is performed by moving the sensor unit 1A based on the processing result of the captured image in step S9 (this is referred to as a second positioning step), and further by moving the sensor unit 1A based on the tonogram data 501 in step S19. Since the positioning (this is called the third positioning step) is performed, the sensor unit 1A can be placed at the optimum position for pulse wave measurement.

Next, the above-described second positioning step will be described in detail.
FIG. 13 shows an example of an optimal measurement point on the radial artery for pulse wave measurement from an anatomical viewpoint, taking the left wrist as an example. For example, it is known that the portion of the radial artery of the left wrist that appears on the body surface is the radial styloid projection as shown in the right side of the wrist in FIG. The radial artery runs between the tendon running in the center of the wrist and the side of the wrist.

  Therefore, the range occupied by the optimal measurement position of the quadrangle in the figure can be expressed on the basis of the features appearing on the wrist surface, that is, the features such as wrist neck, wrist side, wrist centerline, and sebaceous gland in FIG. . In the present embodiment, these features are to be recognized by image recognition, and are stored in advance in the storage unit 401 as feature image data 503 and in advance as feature data 505. When the sensor unit 1A is at the optimal position for pulse wave measurement, in the captured image of the camera 1B, the position data 506 indicating the coordinate position where the feature of the feature data 505 appears is obtained in advance through experiments and stored in the storage unit 401. To do.

  In the present embodiment, to simplify the explanation, it is assumed that the user of the pulse wave measurement device has an average wrist size, and the feature data 503 and the optimum position data 504 are also such users. It is assumed that the data is for.

  14 is unique to an individual, the feature data 503 and the optimum position data 504 should be detected in advance and registered in the storage unit 401 for each user who uses the pulse wave measurement device. Is desirable. At the time of pulse wave measurement, pattern matching is performed with the feature data 503 corresponding to each user, and the optimum position data 504 is searched to detect the movement distance and direction. Thereby, the accuracy of pulse wave detection can be improved in individual units.

  FIG. 15 schematically shows a procedure for detecting the distance and direction of movement in the second positioning step. When image data 300 indicating a rectangular two-dimensional coordinate plane is output from the camera 1B by photographing, the origin O of the coordinates of the image data 300 indicates the current position of the camera 1B, that is, the sensor unit 1A. Further, it is assumed that the area 200 in the image data 300 is an appearance area of a predetermined feature OP when the camera 1B, that is, the sensor unit 1A is at the optimum position.

  Here, if the feature P indicating the predetermined feature OP is detected at the position of the coordinates (X, Y) by the pattern matching unit 413 when the sensor unit 1A is located at the origin O, the sensor unit 1A It can be seen that the current position is not the optimum position but should be moved to the optimum position. The amount of movement is based on the difference between the coordinates (X1, Y1) of the predetermined feature OP and the coordinates (X, Y) of the detected feature P by the movement distance detector 407. X1-X = DX3 and the amount of movement in the Y direction are calculated as Y1-Y = DY3. At this time, since the calculated movement amount indicates a positive value, the movement distance detection unit 407 detects that the direction to be moved is the positive direction in both the X direction and the Y direction.

  Therefore, the drive signal generation unit 408, based on the movement amount in the X and Y directions on the two-dimensional plane detected by the movement distance detection unit 407 and the movement direction (positive direction), each motor 350 and 360 of the motor unit 1C. Generates and outputs a signal for driving. Accordingly, each motor of the motor unit 1C rotates based on the applied drive signal, so that the sensor unit 1A moves in conjunction with the rotation, and can reach the optimum position at the end of the movement.

Next, the above-described third positioning step will be described in detail.
The pulse wave processing unit 410 executes processing for selecting the pressure sensor 26 positioned on the radial artery 27 as an optimum channel from the candidates of the pressure sensor 26 positioned on the radial artery 27 based on the tonogram data 501. . Tonogram data 501 includes, for each pressure sensor 26, DC component data and AC component data indicated by the pulse pressure signal detected by the pressure sensor 26. The pulse wave processing unit 410 specifies that all the pressure sensors 26 whose DC component level is equal to or higher than a certain threshold value are not located on the radial artery 27. The pulse wave processing unit 410 regards the remaining pressure sensors 26 excluding the specified pressure sensor 26 as candidates for pressure sensors located on the radial artery 27. From these candidates, the pressure sensor 26 having a lower DC component level and a higher AC component level is selected as an optimum channel directly above the radial artery 27. In order to detect an accurate and stable pulse wave signal, the optimum channel is required to be the pressure sensor 26 located in the center of the pressure sensor array 11. In step S17, the pulse wave processing unit 410 compares the optimum channel and the channel number of the selected pressure sensor 26 with the channel number of the central pressure sensor stored in advance, and if they match, the optimum position is detected. If it does not match, it is detected that the position is not the optimum position (NO in step S17).

  Therefore, the movement distance detection unit 407 detects the distance between the pressure sensor 26 of the optimum channel selected by the pulse wave processing unit 410 and the pressure sensor 26 located in the center. Specifically, the movement distance detection unit 407 corresponds to the channel number data of each pressure sensor 26 in the pressure sensor array 11 and obtains distance data (distance and direction) between the pressure sensor 26 and the central pressure sensor 26. By searching the stored table 507 of the storage unit 401 and reading the corresponding distance data, the movement amount and direction can be detected.

  The movement amount and direction based on the detected distance are given to the drive signal generation unit 408. The drive signal generation unit 408 generates and outputs a signal for driving the motor 350 of the motor unit 1C based on the movement amount and the movement direction detected by the movement distance detection unit 407. Thereby, since the motor 350 rotates based on the given drive signal, the sensor unit 1A moves in conjunction with the rotation. As a result, at the end of the movement, the sensor unit 1A can reach an optimal position where the pressure sensor 26 located at the center of the pressure sensor array 11 is located almost directly above the radial artery 27.

  Since the pressure sensor array 11 is arranged in the X direction substantially perpendicular to the radial artery 27, in the third positioning step, the movement is only in the X direction, and only the motor 350 of the motor unit 1C operates.

  As described above, the third positioning step is not limited to an automatic one, and as shown in FIGS. 16 to 21, the user manually slides the sensor unit 1 </ b> A in the arrangement direction of the pressure sensor array 11. It may be realized.

  FIG. 16 shows another example of the sensor unit 1. In FIG. 16, at the time of measuring the pulse wave, as shown in the figure, the user places the sensor unit 1A on the surface of the wrist on the radial artery side by sliding movement while the wrist is placed at a predetermined position of the fixed base 2. The housing of the sensor unit 1 and the fixing base 2 are tightened through the belt 8 so that the sensor unit 1 on the wrist is not displaced. When not in the measurement state, the sensor unit 1A is accommodated in the housing, and is guided by the groove 9 and manually slid from the inside of the housing to the outside during measurement, and is positioned on the wrist.

  FIG. 17 shows marks 61 and 62 (arrows with letters “A” and “B”) printed on the casing of the sensor unit 1. The mark 61 in FIG. 17 slides on the side surface of the housing that accommodates the sensor unit 1A by guiding the sensor unit 1A to the groove 9 so that it can be confirmed from the user side with the sensor unit 1 mounted on the wrist. The direction in which the moving operation can be performed is printed with → and ←, and each arrow is printed with characters (“A” and “B”) that uniquely indicate the direction.

  In a state where the sensor unit 1 is mounted on the user's wrist, the characters ‘A’ of the marks 61 and 62 indicate the left side of the user, and the character ‘B’ indicates the right side of the user. Therefore, in a state where the sensor unit 1 is mounted, sliding the sensor unit 1A to the letter 'A' side means that the user slides to the left side, and sliding to the letter 'B' side means to the right side. Refers to slide operation.

  Here, the tonogram created (displayed) in step S15 will be described. FIG. 18 shows an example of display based on the generated tonogram data 501 in association with the arrangement direction of the sensors 26 of the pressure sensor array 11.

  Referring to FIG. 18, tonogram data 501 created by tonogram creating unit 411 associates each of pressure sensors 26 of pressure sensor array 11 with a level indicated by a pulse pressure signal output from the pressure sensor. It is data. The display processing unit 405 reads the tonogram data 501 from the storage unit 401 and displays a graph as shown in FIG. 18 based on the read data. In the graph, the pulse pressure level is represented by the vertical axis VJ, and the horizontal axis HJ is associated with the arrangement of the pressure sensors 26. Then, with the origin O as the starting point of the plot of the graph, the level indicated by the pulse pressure signal output from each pressure sensor 26 in the order according to the arrangement from the A-side pressure sensor 26 to the B-side pressure sensor 26 is continuously set. It is a graph that is plotted. Therefore, with respect to the horizontal axis HJ, the character CH of “A” is displayed in association with the origin O side, and the character CH of “B” is displayed in association with the opposite side of the origin O. The character CH matches the character of the mark 61 printed on the housing of the sensor unit. Therefore, the user can associate the start point or the end point of the plot with the output of the pressure sensor 26 at one end and the other end of the arrangement of the pressure sensor array 11.

  As shown in the figure, the pressure sensor 26 at the center of the pressure sensor array 11 is indicated by a symbol M. When the pressure sensor 26 indicated by the symbol M is located on the radial artery 27, that is, the sensor unit 1A is at the optimum position. The peak value appears on the central axis MJ of the tonogram.

  Therefore, in the third positioning step, the user refers to the displayed tonogram and displays the displayed characters 'A' and 'B' and the mark printed on the housing so that the peak value appears on the axis MJ. The character 61 is collated and the sensor unit 1A is manually slid.

The following functions for guiding the manual slide operation amount may be provided.
A mark 61 on the side surface of the casing of the sensor unit 1 is provided on the upper surface of the casing of the sensor unit 1 so that a user wearing the sensor unit 1 on the wrist can check the sensor unit 1A as shown in FIG. The direction to be slid by being guided by the groove 9 is printed as → and ←, and each arrow is printed with a mark 62 (“A” and “B”) uniquely indicating the direction. Yes.

  Further, as shown in FIG. 19, an opening (window) 67 is formed in a part of the upper surface of the housing. A mark 66 is printed on the upper surface of the sensor unit 1A. As the sensor unit 1A slides while being guided by the groove 9, the mark 66 also moves in the direction of sliding in the opening.

  Here, referring to FIG. 19, a plurality of bar-shaped marks 64 are printed on one side of opening 67 on the upper surface of the housing that houses sensor unit 1A, and these bar-shaped marks are also printed on the other side. A bar mark 64 is printed at a position corresponding to each of the above. Each of the bar-shaped marks is colored with a different color, and the bar-shaped marks positioned correspondingly across the opening 67 are colored with the same color.

  When the sensor unit 1A is slid by the guidance of the groove 9, the mark 66 of the sensor unit 1A is operated to be aligned with the position of the bar mark of any color of the mark 64.

(Dialog display)
In the present embodiment, the direction of sliding along the groove 9 by operating the sensor unit 1A may be guided to the user by displaying the dialogs of FIGS. In order to display the dialog, display data in the RAM 22 is used.

  Based on the tonogram data 501, the pulse wave processing unit 410 detects whether or not the pressure sensor 26 indicating the peak value matches the pressure sensor 26 located at the center of the pressure sensor array 11. If it is not detected that the pressure sensor 26 is located at the center, the display processing unit 405 displays a dialog. That is, guidance for moving the sensor unit 1A to a position where an optimum tonogram can be obtained is displayed.

  Specifically, the display processing unit 405 aligns the mark 66 and the mark 64 with a bar-like mark in the dialog based on the movement amount and direction detected by the movement distance detection unit 407 in step S19. Thus, how much the sensor unit 1A should be moved in which direction is notified. Since the displayed bar-shaped mark coincides with the bar-shaped mark colored in a different color on the upper surface of the housing 100 that accommodates the sensor unit 1A, the sliding direction and the amount of movement are represented by the color of the bar-shaped mark. You can give a guide.

(Examples of other drive units)
In the above-described embodiment, the sensor unit 1A is moved by the motor unit 1C. However, the mechanism for movement is not limited to this, and pressure air may be used. FIG. 22 shows an example of a moving mechanism using pressure air. Since this figure uses the mechanism disclosed in Japanese Patent Laid-Open No. 63-275320, the description will be simplified.

  22, the housing 410 of the hollow sensor unit 1 having an opening 412 at the lower end is detachably attached to the wrist 418 by a band 416 with the opening 412 facing the body surface 414 of the measurement site. A pressing member 432 is attached to the inside of the housing 410 via bellows 420, 422, 424, and 426, which are a kind of telescopic tube, so as to be relatively movable. The housing 410 is attached such that the pressing member 432 is positioned directly above the radial artery 434 (corresponding to the radial artery 27). The pressing member 432 includes a housing 438 having a container shape whose lower end surface 436 is brought into contact with the body surface 414, and a lid body 440 provided at the upper end opening of the housing 438. 1A is disposed. The inside of the pressing member 432 is open to the atmosphere through through holes 460 and 462 provided in the lid 440 and the housing 410.

  Both end portions of the bellows 420, 422, 424 and 426 are airtightly fixed to the inner wall surface of the housing 410 and the outer wall surface of the pressing member 432, and the pressure is regulated by an external pressure regulating valve (not shown) inside the bellows 420, 422, 424 and 426. Pressure air is supplied through a pipe. The bellows 420 and 422 are disposed between the upper inner wall surface of the housing 410 and the outer wall surface of the pressing member 432, and pressure air is supplied from the pressure regulating valve, so that the pressing member 432 is attached to the housing 410. On the other hand, the sensor unit 1A (the pressure sensor array 11) is pressed against the body surface 414 by moving in a downward direction, that is, in a direction toward the body surface 414. On the contrary, when the pressure air of the bellows 420 and 422 is exhausted through the pressure regulating valve, the sensor unit 1A can be separated from the body surface 414.

  Further, in a state where the housing 410 is attached to the wrist 418, the bellows 424 and 426 are disposed between two side portions separated in a direction perpendicular to the radial artery 434. Therefore, when pressure air having the same pressure value is supplied to the bellows 424 and 426 via the pressure regulating valve, the pressing member 432 is approximately in the casing 410 in the direction perpendicular to the radial artery 434, that is, in the left-right direction in FIG. Held in the middle. Further, when pressure air having different pressure values is supplied to the bellows 424 and 426 via the pressure regulating valve, the pressing member 432 has a housing in a direction perpendicular to the radial artery 434, that is, in the left-right direction (X direction) in FIG. Move within 410.

  By adding a driving mechanism using a similar bellows, the pressing member 432 can be moved in the housing 410 in the depth direction (Y direction) of FIG.

  As described above, the pressure air supplied to the bellows 420, 422, 424, and 426 is based on the movement amount detected by the movement amount detection unit 407 and based on the drive signal generated by the drive signal generation unit 408. By adjusting the amount, the sensor unit 1 </ b> A disposed in the housing 438 constituting the pressing member 432 can be moved with respect to the artery 434.

  Therefore, a mechanism for adjusting the pressure air supplied to the bellows shown in FIG. 22 based on the image processing result can be used instead of the drive mechanism by the motor unit 1C.

(Other examples of camera 1B)
In the present embodiment, the camera 1B is attached to one place. However, by attaching the camera 1B to two or more places, the features and position information of the living body can be acquired three-dimensionally and positioning can be performed with higher accuracy. It becomes. The camera 1B may be an infrared camera that does not require a photographing light source.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a hardware block diagram of the pulse wave measuring apparatus which concerns on this Embodiment. It is a hardware block diagram of the pulse wave measuring apparatus which concerns on this Embodiment. It is a figure which shows the connection relation of each part containing a sensor unit and a fixed base. It is a figure which shows the state which mounted | wore the biological body with the sensor unit. (A)-(C) are figures which show the structure of a sensor part. It is a figure which shows the cut surface of FIG. It is a functional lineblock diagram of a pulse wave measuring device concerning this embodiment. It is a figure which shows an example of the information registered into the memory | storage part shown in FIG. It is a figure which shows the moving mechanism using the motor part which concerns on this Embodiment. It is a figure which shows the moving mechanism using the motor part which concerns on this Embodiment. It is a figure explaining the process sequence for the artery position search in the image recognition which concerns on this Embodiment. It is a figure explaining the process sequence for the artery position search in the image recognition which concerns on this Embodiment. It is a figure which illustrates the optimal measurement point for the pulse wave measurement from an anatomical viewpoint. It is a figure explaining the image feature which concerns on this Embodiment. It is a figure which shows typically the procedure for detecting the distance and direction of a movement which concern on this Embodiment. It is a figure which shows the other example of the sensor unit which concerns on this Embodiment. It is a figure explaining the mark printed (printed) on the housing | casing of a sensor unit. It is a figure which shows the example of a display of the tonogram concerning this Embodiment. It is a figure explaining the mark of the side surface of the housing | casing of a sensor unit. It is a figure which shows the dialog display which concerns on this Embodiment. It is a figure which shows the dialog display which concerns on this Embodiment. It is a figure which shows an example of the moving mechanism using pressure air.

Explanation of symbols

  400 control unit 401 storage unit 404 image processing unit 405 display processing unit 406 position detection unit 407 moving distance detection unit 408 drive signal generation unit 410 pulse wave processing unit 411 tonogram creation unit 412 feature extraction unit 413 Pattern matching unit.

Claims (10)

A pressure sensor pressed against the surface of the living body;
A sensor unit having a photographing unit for photographing the biological surface of the pressed part by the pressure sensor and outputting image data; and a sensor unit capable of moving the biological surface;
A feature detection unit for detecting predetermined feature data indicating a predetermined feature of the living body surface corresponding to an artery from the image data;
A movement amount detection unit that detects a movement amount that the sensor unit should move based on a detection position of the predetermined feature data by the feature detection unit and a position registered in advance corresponding to the predetermined feature data; Pulse wave measuring device. The sensor unit further includes a sensor moving unit for moving the sensor unit on the surface of the living body based on a given drive signal,
The pulse wave measuring device further includes:
The pulse wave measurement device according to claim 1, further comprising a drive signal generation unit that generates and outputs the drive signal based on the movement amount detected by the movement amount detection unit. The sensor moving unit includes a motor that rotates according to the drive signal,
The pulse wave measurement device according to claim 2, wherein the sensor unit moves in conjunction with the rotation operation. The sensor moving unit is
An expansion tube that is airtightly attached around the sensor unit and expands and contracts according to the amount of gas inside,
An adjustment unit for adjusting the amount of gas in the telescopic tube according to the drive signal,
The pulse wave measuring device according to claim 2, wherein the sensor unit moves in conjunction with the expansion and contraction. The sensor unit can be slid in the arrangement direction of the pressure sensor array,
The pulse wave measuring device is
Each pressure sensor outputs from the pressure sensor at one end of the pressure sensor array pressed by the pressing portion to the pressure sensor arranged at the other end according to the order of arrangement of the pressure sensors in the array. A graph creation unit for creating graph data continuously plotting pressure data to be
The pulse wave measurement device according to claim 1, further comprising: a display control unit that displays a graph based on the graph data created by the graph creation unit on a display unit prepared in advance. The display control unit
According to the distribution of the pulse pressure indicated by the graph data created by the graph creation unit, the position of the pressure sensor located on the artery is detected in the array, and based on the detected position, the pressure sensor array 6. The pulse wave measuring device according to claim 5, wherein direction indication data for instructing a direction to slide is displayed on the display unit. The pressure sensor is
A pressure sensor array in which a surface on which a plurality of pressure sensor elements are arranged is pressed on the artery so that the arrangement direction of the pressure sensor elements intersects the artery;
A pressing portion that presses the surface of the pressure sensor array onto the artery,
The pulse wave measuring device is
A position detection unit that detects a difference between the position of the artery and the position of the central pressure sensor in the array based on pulse wave information detected by each of the pressure sensor elements of the pressure sensor array;
The pulse wave measurement device according to claim 1, further comprising: a sensor movement amount detection unit that detects the movement amount based on the detected difference.   The pulse wave measurement device according to claim 1, wherein the movement amount indicates a two-dimensional movement amount.   The pulse wave measurement device according to claim 8, wherein the movement amount indicates an amount of movement in a direction in which a first axis intersecting with the artery extends.   The pulse wave measurement device according to claim 9, wherein the movement amount indicates an amount of movement in a direction in which a second axis that intersects the first axis extends.

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