JP2969082B2 - Biological signal display - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a biological signal display device,
In particular, the present invention relates to a device for displaying a waveform of a biological signal such as an electrocardiographic signal.

[0002]

2. Description of the Related Art In a conventional apparatus for displaying a biological signal such as an electrocardiographic signal, a heart sound signal, and a pulse wave signal, a measured biological signal is stored in a video memory or the like as a two-dimensional bit image by A / D conversion. Was. That is, the biological signal is stored in the memory as a series of dots. Then, the biological signal of the bit image is read from the memory, and is displayed on the display device. In such a conventional apparatus, when a reduced display of a waveform is performed, control is performed to increase the read address in steps larger than 1, for example.

[0003]

However, if such read control is performed, if a bit constituting a waveform is present at the skipped address, the bit cannot be displayed, but is displayed. There were problems such as broken waveforms. Particularly in the observation of a biological signal, such a change in the waveform may affect the diagnosis. Here, the biological signal is relatively smooth in the time axis direction as compared with other general measurement signals, and therefore, the above-described problem has become remarkable particularly when the reading is skipped in the vertical direction.

FIG. 4A shows a display image of an original waveform which has not been reduced, and FIG. 4B shows a vertical axis (Y).
A display image of a waveform when the size is reduced by half in the (axis) direction is shown. As shown in (B), the skipped pixels are not reflected on the display image, and the entire waveform image is distorted.

Incidentally, in order to solve the above problem, it is conceivable to perform a process of connecting the waveforms by examining the presence or absence of skipped pixels on two-dimensional coordinates, but in that case, complicated data processing is required. Therefore, it was difficult to perform quick processing.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and has as its object to reduce the size of a sampled signal waveform (especially in the vertical direction) without performing complicated processing and performing data processing. An object of the present invention is to provide a waveform display device capable of reducing and expressing a waveform as faithfully as possible by eliminating skipping of a waveform.

It is another object of the present invention to store a sampled waveform as a one-dimensional waveform value along a time series instead of storing it as a two-dimensional bit image, and then reduce the waveform. It is to provide a waveform display device.

[0008]

In order to achieve the above object, the present invention provides a method for sampling a measured biological signal,
Converting means for converting the waveform values in chronological order; a one-dimensional data memory for storing the chronological waveform values; vertical thinning rate setting means for setting a vertical thinning rate in the vertical direction; Vertical address generating means for generating a vertical address corresponding to the waveform value in accordance with the following, and means for periodically generating a series of horizontal addresses for each of the vertical addresses, as a read address for the one-dimensional data memory. Horizontal address generating means for outputting the horizontal address, and when it can be considered that the m-th waveform value read from the one-dimensional data memory matches the n-th vertical address, or When the n-th vertical address is included between the first waveform value and the n-th vertical address, a match is determined, and specified by the m-th horizontal address and the n-th vertical address A judging means for emitting the pixel,
Display means for displaying a signal waveform composed of the light emitting pixels.

According to the above configuration, the biological signal converted into a digital waveform value (voltage value) is temporarily stored in a one-dimensional data memory. That is, in the data memory, the biological signal is not stored as a bit image but stored as a multi-bit digital value in chronological order.

On the other hand, a vertical address generated under an arbitrarily set vertical thinning rate is compared with a waveform value, and a waveform value that matches or is deemed to match the vertical address (a match determination is obtained) is specified. You. When the coincidence determination is obtained, a two-dimensional waveform can be reproduced from a one-dimensional waveform value by causing the pixel to emit light.

In the above match determination, the m-th waveform value and n
In addition to the case where the vertical address coincides with or can be regarded as the same, the coincidence determination is also performed when the n-th vertical address falls between the m-th waveform value and the (m-1) -th waveform value. Therefore, a problem such as skipping of waveform values does not occur, and a reduced waveform can be easily generated while always considering all waveform values.

In a preferred aspect of the present invention, when the m-th waveform value falls between the n-th vertical address and the (n-1) -th vertical address, the determination means determines that the m-th waveform value and the n-th vertical address are equal. It is assumed that the vertical address matches. That is, the interval between the nth vertical address and the (n-1) th vertical address is equivalent to the skip interval, and
If there is a waveform value in the meantime, it is taken into account.

According to the present invention, as described above, a waveform value can be searched for in a vertical direction of a certain horizontal address, and a waveform value on a horizontal address adjacent to the horizontal address can be considered. The reduced waveform can be reproduced. Further, according to the present invention, adjacent waveform values are considered even in a case where reduction is performed in the horizontal direction. That is, a waveform value that is normally skipped is used in the above-described coincidence determination.

In a preferred aspect of the present invention, the apparatus includes means for setting a horizontal thinning rate in the horizontal direction, and means for thinning the waveform values in the horizontal direction according to the horizontal thinning rate.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a preferred embodiment of a biological signal display device according to the present invention, and FIG. 1 is a block diagram showing the overall configuration.

In FIG. 1, an electrocardiogram signal detector 10 detects an electrocardiogram signal as a biological signal. Of course, the present invention can be applied to the case of displaying other biological signals, for example, a heart sound signal or a pulse wave signal. The electrocardiographic signal output from the electrocardiographic signal detector 10 is
After DC isolation is performed by the A / D converter 14
Are converted into digital waveform values. That is, the analog electrocardiographic signal is converted into a multi-bit waveform value as shown in FIG. Here, the waveform value corresponds to a voltage value. The resolution in the voltage axis direction of the A / D converter 14, that is, the number of bits is, for example, 8 bits. The resolution of the A / D converter 14 in the time axis direction is set to be equal to or more than the minimum resolution for display in the present embodiment.
The minimum resolution corresponds to the size of one pixel in the horizontal direction in the screen.

The electrocardiographic signal converted into a waveform value by the A / D converter 14 is stored in a data memory 16. This is shown in FIG. That is, the data memory 16 is a one-dimensional memory, and stores digital voltage values obtained by sampling for each X address as data. The data memory 16 is constituted by a memory such as a ring buffer.
By performing a predetermined freeze operation, the data stored therein can be fixed. That is, it is possible to reduce and display the biological signal at an arbitrary magnification using the data stored in the data memory 16. In addition,
In the apparatus according to the present embodiment, it is possible to perform enlarged display of a biological signal, but the configuration is not shown.

The sweep rate generator 18 generates a clock for A / D conversion. The clock is supplied to the A / D converter 14 and to the write address generator 20. . The write address generator 20 generates a write address to the data memory 16 based on a clock. For example, when an electrocardiogram signal for a plurality of heartbeats is stored in the data memory 16, the write address generator 20 periodically generates a write address with the plurality of heartbeats as one cycle.

The TV clock generator 22 is for generating horizontal and vertical synchronizing signals on the CRT 24 on which the biological signal is displayed, and based on the basic clock output from the TV clock generator 22. , A horizontal address generator 26 generates a horizontal address x _m as a read address of the data memory 16. Also, T
Based on the basic clock output from the V clock generator 22, a vertical address generator 28 is producing vertical address y _n. The TV clock generator 22 outputs a TV synchronization signal 100 to a video processing circuit 30 described later.

The vertical thinning rate setting unit 32 outputs the thinning rate to the vertical address generator 28 in order to set a vertical reduction rate. The vertical thinning rate can be arbitrarily set by a user, for example. Here, the generated vertical address corresponds to a sampling level in the A / D converter 14. On the other hand, the horizontal address corresponds to each sampling time. Each time one of the vertical address y _n are generated, M-number of the horizontal address x _m is generated.

The determiner 34 performs a match determination described in detail below in accordance with the determination conditions shown in FIG.
In order to determine the coincidence, the waveform value D _m specified by the horizontal address x _m on the data memory 16 is determined by the decision unit 3.
4, and the waveform value D _m−1 delayed by one data by the delay unit 36, that is, the waveform value D _m−1 immediately before the X address is input to the decision unit 34. Also, the vertical address y _n
Is input to the determiner 34, and the immediately preceding vertical address yn _-1 that has been delayed by the delay unit 38 for a time corresponding to one horizontal period is also input to the determiner 34.

The determination unit 34 is basically performs a matching determination when the vertical address y _n is equal to waveform value D _m, in consideration of the decimation in the vertical direction in the case of the following three A match is being determined. The first condition is as follows.

Y _n−1 <D _m ≦ y _n (1) The first condition is that, when the X address of interest is x _m , the waveform value D _m on that address is n-th. Is determined to be a match when it falls between the vertical address and the (n-1) th vertical address. Of course, also naturally match determining when the waveform value D _m and a vertical address y _n match takes place.

The second condition is as follows.

D _m-1 <y _n <D _m (2) The second condition is that the m-th waveform value is larger than the (m-1) -th waveform value, and the vertical Address y
_{When n} is entered, a coincidence determination is performed in order to provide continuity of the waveform.

The third condition is as follows.

D _m <y _n <D _{m -1} (3) The third condition is the m-1 th position immediately before in the horizontal direction, contrary to the condition (2). a case towards the m-th waveform value than the waveform value is small, when between them entering the vertical address y _n, and performs matching determination to achieve continuity of the waveform.

Note that under the above determination conditions, FIG.
As shown in (A), the sampling level is high along the vertical direction. Of course, a coordinate system in which the sampling axes are increased from bottom to top by inverting the coordinate axes may be adopted.

When the above-described determination conditions are satisfied,
Pixel value of the pixel or pixels to be identified to the x _m and y _n is 1, it is a 0 for the other pixels.

Therefore, according to such a determination condition, even if the vertical address generator 28 performs address thinning in the vertical direction, that is, even if the sampling level to be referred to is skipped, the thinning is performed. A waveform can be generated in consideration of the waveform value of the portion that has been changed, and according to the present embodiment, the pixel value can be determined in consideration of the waveform value adjacent in the horizontal direction. Therefore, the problem that data existing on the skipped address is not displayed, which has been regarded as a problem in the related art, can be solved, and a break in a waveform can be solved.

FIG. 4C shows a display image of the reduced waveform created by the present embodiment, and the original waveform image is left.

The horizontal thinning rate setting unit 40 in FIG.
A horizontal thinning circuit 42 for setting a horizontal reduction ratio
, And outputs a horizontal thinning rate. The horizontal thinning rate is set by, for example, a user. The horizontal thinning circuit 42 thins out the data of each pixel along the time axis output from the determiner 34 at a horizontal thinning rate, thereby reducing the horizontal waveform.
Although the thinning-out in the horizontal direction is performed on the output side of the determiner 34 in the present embodiment, the thinning-out in the horizontal direction can be performed on the input side of the determiner 34. However, in this case, the determination unit 34 in spite of thinning of such horizontal, it is necessary to waveform value D _m-1 before the one with the waveform value D _m is input.

The video processing circuit 30 receives the TV synchronization signal 10
An image to be output to the CRT 24 is generated based on 0, and the waveform size and the like on the screen are adjusted. Of course, necessary numerical data and the like are also displayed on the screen displayed on the CRT 24.

The above embodiment can be applied to a case where a so-called interlace scan is performed on the CRT 24. In this case, the vertical address generator 2
In 8, by generating a y _n-1 at the same time as y _n, it suffices them so as to input to the determiner 34.

[0036]

As described above, according to the present invention,
In particular, when the sampled signal waveform is reduced and displayed in the vertical direction, the waveform can be skipped and the waveform can be reduced as faithfully as possible without performing complicated processing. Further, according to the present invention, a sampled waveform can be stored as a one-dimensional waveform value along a time series without being stored as a two-dimensional bit image, and then the waveform can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an overall configuration of a biological signal display device according to the present invention.

FIG. 2 is a diagram illustrating sampled waveform values and data contents stored in a data memory.

FIG. 3 is an explanatory diagram showing determination conditions in a determiner.

FIG. 4 is an explanatory diagram showing a conventional problem and an effect of the present invention.

[Explanation of symbols]

14 A / D converter, 16 data memory, 18 sweep rate generator, 20 write address generator, 26
Horizontal address generator, 28 vertical address generator, 3
2 Vertical thinning rate setting device, 34 judgment device, 40 horizontal thinning rate setting device, 42 horizontal thinning circuit.

Claims (4)

(57) [Claims] 1. Sampling a measured biological signal,
Conversion means for converting to waveform values in chronological order; a one-dimensional data memory for storing the waveform values in chronological order; vertical thinning rate setting means for setting a vertical thinning rate in the vertical direction; Vertical address generating means for generating a vertical address corresponding to the waveform value according to the following: means for periodically generating a series of horizontal addresses for each of the vertical addresses, the read-out address for the one-dimensional data memory Horizontal address generating means for outputting the horizontal address, and when the m-th waveform value read from the one-dimensional data memory and the n-th vertical address can be regarded as coincident, or when the m-th waveform value and m- When the n-th vertical address falls between the first waveform value and the n-th vertical address, a match is determined, and A judging means for emitting the pixel to be constant, biosignal display apparatus characterized by comprising a display unit which is configured signal waveform is displayed in the pixel being light. 2. The apparatus according to claim 1, wherein the determining means determines that the m-th waveform value falls between the n-th vertical address and the (n-1) -th vertical address.
A biological signal display device, which regards that the n-th vertical address and the n-th vertical address match. 3. The biological signal display device according to claim 1, wherein the biological signal is any one of an electrocardiographic signal, a heart sound signal, and a pulse wave signal. 4. The apparatus according to claim 1, further comprising: means for setting a horizontal thinning rate in a horizontal direction; and means for thinning the waveform value in the horizontal direction according to the horizontal thinning rate. Biological signal display device.