JPS63212327A - Acceleration pulse wave detector - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an acceleroplethysmometer used for health checks in health care rooms, training centers, and the like.

2. Description of the Related Art Conventionally, this type of accelerometer has been designed to obtain the maximum acceleration pulse wave by further differentiating the acceleration pulse wave obtained by second-order differentiation of the pulse wave to obtain a third-order differentiation.

There is a known device that calculates the minimum value, digitizes the characteristics of the waveform based on this value, and displays and records it (Japanese Unexamined Patent Application Publication No. 1987-
93036).

Problems to be Solved by the Invention In such a conventional configuration, it is necessary to perform the differential operation repeatedly, and if this was attempted to be done on an electronic circuit, the circuit configuration would be extremely complicated, and the digital Even if one were to try to do this by applying a microcomputer, etc., the problem was that the program software would have to be cumbersome.

The present invention solves these problems, and it is possible to calculate the positional relationship between each peak of an accelerated pulse wave without performing differential operations that may cause troublesome circuit or program problems in order to find the extreme values. It attempts to find the extreme values of waveforms using the characteristics possessed by simple comparison operations.

Means for Solving the Problem In order to solve this problem, the present invention uses an acceleroplethysmometer with a blood flow pickup that detects the flow of blood in the fingertip or earlobe, and a pulse waveform that is the output waveform of this blood flow pickup. An acceleration pulse wave conversion device that second-order differentiates the wave, converts it into an acceleration pulse wave, and outputs it as digital data; and a memory that stores the digital data obtained from this acceleration pulse wave conversion device and calculates an index representing the characteristics of the waveform. and a data storage unit that stores the digital output as temporally continuous data, and a maximum value that selects the maximum value and its position from among the digital data stored in the data storage unit. A detection unit, a minimum value detection unit that also selects the minimum value and its position, and a comparison unit that compares the data in the data storage unit with a predetermined value in order from the oldest in time and selects a plurality of pieces of data that match this. a position calculation unit that similarly calculates the temporal position of the data in the data storage unit and calculates the temporal position based on the temporal distance between a plurality of data; It also consists of an index calculation unit that calculates an index representing the characteristics of the accelerated pulse wave.

Function: With this configuration, the extreme value of the accelerated pulse wave, which was conventionally determined by advanced mathematical methods such as cubic differentiation, can now be determined by simple calculations that utilize the waveform characteristics of the accelerated pulse wave. be.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 4. In Figure 1, 1 is a blood flow pickup;
The blood flow in the fingertip or earlobe is detected by photoelectric conversion or impedance conversion. Reference numeral 2 denotes an accelerated pulse wave converting device that secondarily differentiates the pulse wave detected by the blood flow pickup 1, converts it into an accelerated pulse wave, and outputs the converted pulse wave as digital data. Reference numeral 3 denotes a storage/arithmetic unit that stores the digital data obtained from the acceleration pulse wave converter 2 and calculates an index representing the characteristics of the waveform. A data storage unit 4 (RAM etc.) that stores temporally continuous data, a maximum value detection unit 6 that selects the maximum value and its position from the stored digital data, and a minimum value detection unit that also selects the minimum value and its position. A comparing section 6 compares the data in the data storage section 4 with a predetermined value in order from the oldest in terms of time, and selects a plurality of pieces of data that match the predetermined value. a position calculation unit 8 that calculates the temporal position by calculating the temporal position by calculating the temporal position by calculating the temporal position based on a predetermined simple calculation formula based on the temporal distance between a plurality of data; It incorporates an index calculation section 9 that calculates an index representing the characteristics of the accelerated pulse wave. Reference numeral 10 denotes a display device that displays the accelerated pulse waveform, index, etc. obtained by the storage/arithmetic device 3.

To explain the operation in the above configuration, the pulse wave detected by the blood flow pickup 1 is transferred to the acceleration pulse wave converter 2.
In order to calculate the index representing the characteristics of the accelerated pulse wave waveform, it is converted into an accelerated pulse wave waveform and stored in the data storage unit 4 as digital data.

The peak values of b, c, d and their temporal positions ta.

tb, to, and td are required.

First, as shown in FIG. 2, the maximum value detection section 6 determines the maximum value a within a range of a predetermined threshold h or more and its temporal position 1a.

Next, in a similar manner, the minimum value below h' is determined by the minimum value detection section 6. However, here, the waveform of the accelerated pulse wave is not only the case where the valley of d is shallower than the valley of b as shown in Fig. 2, but also the case where the valley of d is shallower than the valley of b as shown in Fig. 3.
It has been experimentally confirmed that the trough can be deeper than the trough in some cases. In this case, in the above-described method, d instead of b is determined as the minimum value. Furthermore, as shown in FIG. 4, cases where the peak C exceeds the base line X have also been confirmed.

Therefore, in order to determine whether the minimum value obtained by this method is b or d, the following means is used.

In other words, the maximum value a' of the next waveform is determined using the same method used to determine the maximum value a, and the distance L between a and a' (the fourth
(see figure) is determined by the position calculation unit 8. At this time a, b,
It has been confirmed by many experimental data that the peaks of a and d are within L/3 from a, so the intersection of the baseline X and the waveform is within Li2 from a! 1~
I4 is detected using the comparison section 7. Here, in the case of a waveform like that shown in Figure 2 or Figure 3, the intersection with the base line X is xl
, x2. Therefore, if there are three or more intersections, it can be considered that the waveform is of the type shown in Figure 4, and the minimum value determined by the minimum value detection section 6 is b, and the same x2 means! 3 questions and I3~x4
It is possible to obtain the peaks c and d between them by applying the peaks c and d between them.

Next, in the case of the waveforms in Figures 2 and 3, the minimum value is b
It is necessary to determine whether it is d or d.

Regarding this point, which is also confirmed by experimental data, if there is a minimum value within 1/2 of the midpoint of the distance l between x1 and x2, that is, 11, then this point It has been confirmed that b. Therefore, if this is calculated using the position calculation section 8, it can be seen that the minimum value obtained by the minimum value detection section 6 is b in the case of FIG. 2, and d in the case of FIG. c, d(
Alternatively, to determine b), change the predetermined value to be compared in the comparing section 7 between b (or d) and the base line It is clear that the rest can be found using the same means used to find c and d in Figure 4.

By using a, b, c, and d obtained in the above manner, an index representing the characteristics of the accelerated pulse wave waveform can be calculated by the index calculating section 9, and this calculation result and the waveform can be displayed on the display device 1.
o can be displayed.

Effects of the Invention As described above, according to the present invention, the characteristics of the positional relationship of each peak of an accelerated pulse wave, that is, a
a within % between xa'.

There are peaks b, c, and d, and x1~! Utilizing the characteristics such as the fact that the minimum value within % of 2 is b, it is possible to find the peak of the acceleration pulse waveform by simple calculations. It is an extremely useful tool that allows you to easily and easily understand and accurately calculate indices that are said to have great significance.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention, and FIGS. 2 to 4 are explanatory diagrams for facilitating understanding of the present invention. 1... Blood flow pickup, 2... Accelerated pulse wave conversion device, 3... Memory calculation device, 4...
...Data storage unit, 6...Maximum value detection unit,
6... Minimum value detection section, 7... Comparison section,
8...Position calculation unit, 9...Mountain index calculation unit. Name of agent: Patent attorney Toshio Nakao and 1 other person1-
- frnlL reference fig. 1 2-Kien leak disaster selection temporary I3---Published by myself! ; Extravagant ■ (Blank L J 2nd
Figure 3 Figure 4

Claims (1)

[Claims] A blood flow pickup that detects the flow of blood in a fingertip or earlobe, and an acceleration pulse wave conversion device that takes second derivatives of the pulse wave that is the output waveform of this blood flow pickup, converts it into an accelerated pulse wave, and outputs it as digital data. , and a storage/arithmetic device that stores digital data obtained from this acceleration pulse wave conversion device and calculates an index representing characteristics of the waveform, and the storage/arithmetic device stores the digital output as temporally continuous data. A data storage section for storing, a maximum value detection section that selects the maximum value and its position from the digital data stored therein, a minimum value detection section that also selects the minimum value and its position, and further the data storage section. A comparison unit that compares data with a predetermined value in order from the oldest in time and selects a plurality of pieces of data that match the predetermined value, and also calculates the temporal position of the data in the data storage unit, and An acceleroplethysmometer consisting of a position calculation unit that calculates the temporal position based on the temporal distance, and an index calculation unit that calculates an index representing the characteristics of the accelerated pulse wave based on the results obtained. .