JPS60135834A - Surface pressure measuring apparatus - Google Patents

Abstract

PURPOSE:To enable the detection of parts subject to pressure accurately by a method wherein a surface pressure to be measured is received with a pressure receiving matt made of an elastic material with conical projections distributed evenly to convert a load received on each projection into an electrical signal from a light pattern. CONSTITUTION:A pressure receiving matt 12 has conical projections 15 distributed evenly with tips thereof point contacts a transparent board 13 and a light source 16 is provided at one end face of the transparent board 13. When a surface pressure P to be measured is applied on the pressure receiving matt 12, the projection 15 squeezes significantly at the part receiving the surface pressure intensely to make the contact area form a large circle. Light propagating incident on the transparent board 13 from the light source 16 forms a circular light pattern in the size corresponding to a load and reflected with a reflector 19 entering a video camera 20, with which a circular image 22 of the light pattern is formed in a square region of a unit area. The quantity of light of the light pattern is converted into an electrical signal for each pixel with the area smaller than the area of each projection and then, into a load signal.

Description

[Detailed description of the invention] This invention is medical science...Bilichy/Yon 2 Physical Education.

The present invention relates to a device for measuring blood pressure, which is used in various fields such as mechanical vibration systems.

<Prior art> Conventionally, for example, the relationship between exercise and the human body has been analyzed by measuring the force exerted on the ground that the feet are in contact with during exercise, and this has led to various studies in the fields of medicine and physical education. Research has been conducted on its use. Conventionally, this has been measured by using a pressure receiving plate to receive the force exerted by the foot on the ground due to movement, and measuring the total force.

In such devices, it is not possible to measure what kind of pressure is applied to each part of the plantar area of the foot.

From this point of view, it has been proposed to wear special shoes in which pressure-sensitive elements are evenly distributed so as to detect the pressure received from each part of the foot, and to detect the pressure received from each pressure-sensitive element. In this case, it is difficult to uniformly distribute a large number of pressure sensitive elements, resulting in poor resolution.

Furthermore, in the past, a rubber pressure-receiving mat in which cylindrical protrusions of approximately the same size were closely spaced and evenly distributed was used, and this was placed on a glass plate with the protrusion side touching, and a human being was placed on the pressure-receiving mat. When the mat is stepped on, the protrusions on each part of the mat are crushed by the foot, and the light incident from the side of the glass plate is diffusely reflected on the crushed protrusion surface of the mat, which converts the crushed state of each protrusion into a circular light pattern. In other words, in the areas that receive strong pressure, the protrusions are crushed to a large extent and the circular contact area in contact with the glass plate becomes wider, creating a brighter light source, while in areas where the full heat is not applied, only the tips of the protrusions make contact with the glass plate. 9 In order to obtain a distribution of light patterns whose area corresponds to the pressure without substantially reflecting light from them, and from this, to display an isobaric region, that is, a region of almost uniform pressure. It has been proposed to defocus the distribution of a small circular pattern of light to make it indistinguishable from the continuous changing light intensity distribution, and to display the intensity distribution. In this case, small contact pressures cannot be distinguished due to out-of-focus photography, and only large pressure areas can be displayed.Moreover, the relationship between light intensity and pressure is sufficiently high for the large pressure areas. It is not possible to detect accurately, and furthermore, continuous light intensity slams cannot accurately determine the contact area or shape of the ground surface, since it is difficult to detect the outline of a small foot.

<Summary of the Invention> An object of the present invention is to provide a blood pressure measuring device that can accurately detect each part receiving pressure and also accurately know the outline of the pressure receiving surface.

According to this invention, the surface pressure to be measured is received by a pressure-receiving mat made of an elastic material in which conical projections are uniformly distributed, and the load received by each projection is converted into a light pattern having an area corresponding to the size of the projection. do. The converted light beam is converted into an electric signal for each pixel having an area smaller than the area of each protrusion, and the converted electric signal for each pixel is stored. The amount of light received by each protrusion is calculated from the stored electrical signal, and the load received by each protrusion is obtained from the calculated amount of light received. As a result, the load distribution of the load applied to each window riser by the unit area of the protrusion or light of the pressure receiving mat is obtained, and this load distribution is displayed on a cathode ray tube display, a printer, etc. In addition, if necessary, the load center of the surface pressure to be measured, for example, the center of gravity, is calculated from the load of each protrusion, or the ground contact area, that is, the area of the protrusion that has received a load of a predetermined value or more, is calculated. It is also possible to divide the pressure receiving surface into a plurality of regions and calculate the load center for each divided region.

<Example> Hereinafter, an example of the surface pressure measuring device according to the present invention will be described with reference to the surface □□□. In FIG. 1, a measuring table 11 is provided, and a pressure receiving mat 12 is arranged on the upper surface of the measuring table 11. As shown in FIG. As shown in FIG. 2, the pressure receiving mat 12 has, for example,
Conical protrusions 15 having a height of 3wn and a diameter of 5ml are uniformly distributed adjacent to each other for each unit area on four sides, and are made of elastic material, for example, rubber, and the protrusions 15 side are arranged as the measuring table 11 side. The part of the measuring table 11 where the pressure receiving mat 12 is arranged, that is, the upper surface, is made of a transparent plate 13 such as a glass plate. A human stands on 12 with feet 14
Surface pressure is applied to the pressure receiving mat 12 by the pressure receiving mat 12.

As shown in FIG. 2, the pressure-receiving mat 12 has conical protrusions 15 evenly distributed, and their tips are placed in point contact with the transparent plate 13. A light source 1 is provided on one end surface of this transparent plate 13.
6 is arranged, and the light from the light source 16 enters the transparent plate 13 and propagates within the transparent plate 13 while being totally reflected as shown by the dotted line.

A surface pressure P to be measured is applied to the pressure-receiving mat 12, and the projections 15 are greatly crushed in the portions that receive this surface pressure strongly.
is crushed, and the circular contact surface that contacts the transparent plate 13 is a circular contact surface N71+1 corresponding to each protrusion as shown in FIG.
72 + 17a + 174 + 17s, and the contact area of the protrusion 153 that received a strong load is a large circle 17
It is 3. Light that enters the interface at an angle within the critical angle determined by the ratio of refractive index between air and the transparent plate 13, such as a glass plate, is totally reflected in areas that are not in contact with the pressure-receiving mat 12 and the tab projections 15. However, in the portion where a certain area is in contact with the protrusion 15, the reflection is not restricted by the critical angle and is determined by the refractive index value of the rubber that is a component of the pressure receiving mat 12. At a certain rate, the light is diffusely reflected as shown by the solid arrow 18 in the figure. Therefore, when this is done as a light batt, the circular light batts distributed according to each load shown in FIG. 3 can be obtained.

Figure 4 shows an example of the distribution of the light bumps obtained by the foot.In this way, the surface pressure to be measured is a circular pattern distribution of the light bumps, which have an area corresponding to the pressure received by each protrusion. This light pattern is converted into an electric signal for each pixel having an area smaller than the unit area in which the protrusion is formed.

For example, as shown in FIG.
A reflecting mirror 19 is disposed diagonally opposite to the reflecting mirror 1.
9, the reflected light pattern is photographed with the video camera 2O installed on the side of the measurement table 11. As mentioned earlier, one protrusion 15 has a diameter of 511111 within a rectangular area of 5 x 5. It is formed as a conical projection with a bottom surface, and a contact area 17 corresponding to the load received per unit area of the projection formation is obtained, and the video camera 20 has a rectangular shape of the unit area as shown in FIG. A circular image 22 of a light pattern is formed in the area 21, and this rectangular area 21 of unit area is divided into, for example, 20 pixels 23 of 4×5, and the amount of light in each pixel is measured by the video camera 20.
Detect with. In other words, the scanning line spacing of the video camera 20 corresponds to the spacing of the pixels 23 in the vertical direction in FIG.
The resolution in each scanning line corresponds to the pixel interval in the horizontal direction of the pixels 23. If this one pixel 23 completely falls within the circular light pattern image 22, the strongest light amount is detected, and if the batten images 22 overlap completely, the light amount of the pixel 23 is zero, and the light amount within one pixel 23 is zero. Batan statue 2
A ratio of 2 gives the photoelectric charge at that pixel.

The amount of light for each pixel is converted into electrical signals of 16 levels.

In FIG. 1, the distribution of the light pattern is photographed using the video camera 20 according to the relationship described above, and the output is sent to the AD converter 2.
4 is input. In the AD converter 24, when a capture command is given from the computer 25, the output of the video camera 20 is converted at high speed from the vertical synchronization signal of the video camera 20 immediately after the capture command is given, and the output of the video camera 20 is sent to the digital camera at high speed.
This sampling in the AD converter 24 is performed at such a speed as to sample the electrical signal of each pixel 23 in FIG. 5. In this way, the operation of capturing one screen, that is, one screen of the light bombardment distribution generated on the entire effective surface of the pressure receiving mat 12, into the memory 26 is stopped.

The computer 25 then selects each protrusion 15 to
``I store electrical signals indicating the amount of light of each of the 20 pixels in the memory 26.
The light quantity signal is read out from the area, the sum of the light quantities per unit area is calculated, and the light quantity signal is converted into a load signal with reference to the symmetry table (FIG. 6) 27 showing the relationship between the light quantity and the load. That is, the relationship between the load applied to each protrusion 15, its contact area, and the amount of light determined by the Im angle of the Libertan image 22 is stored in advance in the symmetry table 27, and for example, if the signal indicating the amount of light is 0. When the load is 0.04, the load is 0.02 K9, when the light amount signal is 005, the load is 0.025, and so on, with an accuracy of 51. Corresponding to the maximum load, the received light amount signal is 200.
A symmetrical table 27 containing numbers from 250 to 250 is recorded in advance in the memory of the computer 25.

Calculate the sum of the light intensity signals of each pixel for each protrusion, refer to the symmetry table 27, calculate the load applied to one protrusion, and store this in the load 1 distribution memory 28 in FIG. . In this way, when the loads applied to all the protrusions of the pressure-receiving mat 12 are completely stored in the Shunto distribution memory 28,
The obtained load distribution is extracted from the memory 28 and displayed on the graphic display 29 (FIG. 1), which is a display device, or on the graph ink printer 31. An example of the print display is shown in FIG. Dark partial sums indicate large isocart areas. When displaying on the graphic display 29, different equal load areas can be displayed in different colors to make them easier to see.

Furthermore, if necessary, the center of the surface pressure to be measured, in the case of a human body, the center of gravity is calculated. For this calculation, for example, the reference coordinates are given to the pressure receiving mat, and the X-axis coordinates are set to
I l x2. x3, X4""" and y@[
If the coordinates are '11r 3'2 + y3+ y4..., and the load received by the protrusion 15 whose position is specified by the coordinates (XI, Yl) is f1+, and the load received by the protrusion is fe2... , the X value of the center coordinate of the surface pressure is obtained by calculating the y coordinate, respectively. To calculate the ground contact area of the foot when stepping on the pressure-receiving mat, it is sufficient to multiply the number of protrusions with a load greater than a certain value by their unit area, which in this example is 5 x 5 m. Furthermore, what is convenient about this device is that, for example, when you are standing on a pressure-receiving mat with both feet, from the data obtained, the center of gravity of each foot can be calculated from the load received by each protrusion of that one foot in the same way as before. Of course, the ground contact area can also be calculated.

In history, the partial load center such as the thumb area, or the area of the surface pressure to be measured is divided into six equal parts, and the partial load center and ground contact area of each divided part are calculated. can be similarly calculated. For example, Figure 7 shows a case where a person measures the pressure distribution while standing on a pressure-receiving mat and prints out the results on a printer.The center of gravity position is displayed as G, and the center of gravity position of each foot is U
and L, and the numerical value below the display shows that when the surface pressure of and is divided into six equal parts, the load of the upper three divided areas is 4.7 t<g, 5.1 Kg, 17. 7
Kg, the load on the upper leg is 27.5 Kf, and the result is displayed, and the ground contact area is 1.5 Kg. ．．
9.2, 20.0, 25.0.

642 is displayed. 6.5 Regarding the lower three areas
Ky, 5.7Kf, 18.3Kg, 30.6
Ky, 18.5, 20.7, 27.0.

66.2 is displayed. The ground contact area is expressed as, for example, a load received by one protrusion of 0.02 Ky or more.

Effect> As described above, in the surface pressure measuring device according to the present invention, the unit area portion of one protrusion is divided into a plurality of pixels, and the light intensity of the light pattern is calculated for each pixel of the pixel. detect,
Accurately know the load per unit area by calculating the sum for each unit area and converting it to a pre-calibrated load to obtain the load per unit area and use it as the load received by the protrusion. In this case, the relationship between the load and the circular bang was confirmed by experiment, for example, as shown in Figure 9, as the load increases, the diameter of the light bang becomes smaller. The relationship between the amount of light obtained in this way and the applied light sound obtained for one protrusion abutment is almost the same when the load is increased and when it is decreased, as shown in Figure 10. The black circle indicates the case where the increase in
The case where the load is reduced is shown by a white circle. In addition, rubber pressure mats have a very fast ability to follow changes in load, so for example, it is possible to measure the pressure distribution applied to a foot instantaneously while moving on the mat. It is possible. In this case, if the processing speed of the computer is increased appropriately, it is possible to process in real time without having to carry out arithmetic processing after continuously photographing the state of change in the light batten distribution due to movement with a video camera. In FIG. 1, the video signal taken by the video camera 20 may be recorded on the VTR 33, the VTR 33 may be played back, and the playback output may be taken into the video memory 26 through the AD converter 24.

In this way, the distributed load can be measured with high precision, and the contact area can also be determined, and processing can be performed at high speed. It is also possible to measure in units of load durams as in the previous example. In addition, this invention applies not only to foot pressure loads but also to blood pressure from other parts of the human body such as the back and buttocks, as well as changes in surface pressure due to vibrations, such as surface pressures received from general objects, especially surface pressures received from vibrating objects. It is also possible to measure the following.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an example of a blood pressure control device according to the present invention, and Fig. 2 shows its pressure receiving mat 12 and transparent plate 13.
FIG. 3 is a diagram showing changes in the contact area of the protrusion of the pressure-receiving mat with the cart, and FIG. 4 is a diagram showing an example of the light slam distribution due to surface pressure.
Figure 5 is a diagram showing the relationship between pixels and light baton images in each unit area, - Figure 6 is a diagram showing the symmetry table and load distribution memory in the memory used in the computer, and Figure 7 is the back side. Figure 8 shows an example of surface pressure measured values printed out using a printer, Figure 8 shows the relationship between load distribution and position coordinates, and Figure 9 shows the experimental results of the relationship between load and optical pattern diameter. , FIG. 10 is a diagram showing the experimental results of the relationship between the load and the calculated light amount of one protrusion. 11: Measuring table, 12: Pressure mat, 13: Transparent plate, 15
: Protrusion, 16: Light source, 19: Mirror, 20: Video camera, 22: Light slam image, 25: Computer, 24:
AD converter, 26: video memory, 29 Nigella quick display, 31 Nigella quick printer 0 Patent applicant Educational corporation Doyo Gakuen 71 O. o 00 ○ OOo o. 0 00 QOOOO. , 000000000 - oooooooOQ ''' OOOOOOOo a looO00○Q Q 6 ・ 000o○000 ・ , ooO○OOOO

Claims (1)

[Claims] (1) Pressure-receiving pine with almost uniformly distributed conical projections) [Means for applying surface pressure to be measured and converting the surface pressure to be measured into a distribution of an optical pattern having an area corresponding to the load received over a unit area and a means for converting the converted light pattern into an electrical signal for each pixel having an area smaller than each protrusion;
Means for storing the converted signal for each pixel, means for calculating the amount of light received for each protrusion from the stored electric signal, and means for converting the amount of light received for each protrusion into a load. and means for displaying the obtained load distribution.