Whole-process verification method for digital electrocardiograph

Abstract

The invention discloses a full-process verification method for a digital electrocardiograph, and relates to the technical field of metrological verification. The invention provides a full-process verification method for a digital electrocardiograph, which comprises the following steps: firstly, acquiring a pixel-millimeter scale through steel ruler image analysis, analyzing and correcting an inclination angle of an output signal image of the digital electrocardiograph through an RANSAC (Random Sample Consensus) algorithm, and acquiring a threshold binarization threshold by using a kmeans algorithm; according to the method, self-adaptive binaryzation of color scanning images is achieved, robustness is higher, automatic verification methods based on digital image processing are designed for all verification processes related to the digital electrocardiograph, full-process verification of the digital electrocardiograph can be achieved, and the full-process verification efficiency and verification accuracy of the digital electrocardiograph are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of metrological verification, in particular to a full-process verification method of a digital electrocardiograph. BACKGROUND

[0002] The digital electrocardiograph is an instrument used to record and display physiological electrical signals generated by heart activity. The output electrocardiogram of the digital electrocardiograph is one of the common diagnostic bases in clinical diagnosis. In order to ensure the quality of clinical application of the digital electrocardiograph and protect the safety of patients and the accuracy of diagnosis results, the digital electrocardiograph usually needs to be periodically verified before being put into use and during use, so as to avoid the situation that the digital electrocardiograph is abnormal or does not meet the requirements.

[0003] In order to improve the verification efficiency of the digital electrocardiograph, the related technologies propose a digital electrocardiograph verification method based on an electrical signal processing method and a digital electrocardiograph verification method based on image processing. For example, patent CN104840194B discloses the following technical solution: an access module is used to receive and record the electrocardiogram output by the digital electrocardiograph to be tested, and an identification module is used to verify various indexes of the electrocardiogram, thereby improving the verification efficiency and accuracy. Patent CN115512130A discloses a paper electrocardiogram waveform parameter automatic measurement method based on image processing, which includes electrocardiogram image acquisition, electrocardiogram image tilt correction, electrocardiogram background grid removal, electrocardiogram waveform extraction, and electrocardiogram data calculation. The detection and identification of the electrocardiogram waveform and the parameter calculation are realized through an industrial camera and an AI algorithm, and the detection efficiency is high and the measurement accuracy is high.

[0004] In the process of implementing the present application, it is found that the related technologies have the following technical problems: The digital electrocardiograph verification method provided by the related technologies can only realize the verification of the ECG signal parameters of the digital electrocardiograph, and needs to be combined with additional multiple verification methods to realize the full-process verification of the digital electrocardiograph, which leads to low full-process verification efficiency of the digital electrocardiograph and cannot guarantee the verification accuracy due to different verification methods. SUMMARY

[0005] In order to solve the above problems existing in the prior art, the present application provides a full-process verification method of a digital electrocardiograph, which is used to realize the full-process verification of the digital electrocardiograph and improve the full-process verification efficiency and accuracy of the digital electrocardiograph. The technical solution provided by the present application is as follows: According to an aspect of an embodiment of the present application, a full-process verification method of a digital electrocardiograph is provided, characterized in that the full-process verification method comprises: S10: acquiring a standard steel ruler image corresponding to the digital electrocardiograph, and determining a pixel-millimeter scale corresponding to the standard steel ruler image according to the standard steel ruler image. S20: For each calibration procedure corresponding to the digital electrocardiograph, an output signal image corresponding to the calibration procedure is obtained, and the output signal image is preprocessed; S30: According to the pixel-millimeter scale, image analysis is performed on each preprocessed output signal image, and signal parameters are calculated respectively, each calculated signal parameter is compared with the corresponding standard, and the digital electrocardiograph whose each signal parameter meets the corresponding standard is determined as qualified.

[0006] In a preferred embodiment, S10 comprises the following steps: The standard steel ruler corresponding to the digital electrocardiograph is scanned to obtain a standard steel ruler image corresponding to the standard steel ruler; The wide side of the standard steel ruler image is determined by Hough transform, the number of pixels p in the wide side of the standard steel ruler image is calculated, and the pixel-millimeter scale corresponding to the standard steel ruler image is calculated according to the following formula In the above formula, w is the actual length of the wide side of the standard steel ruler, and the unit is millimeter.

[0007] In a preferred embodiment, the step of preprocessing the output signal image in S20 comprises: The output signal image is grayed to obtain a gray image; N black pixel points randomly selected in the gray image are determined as sampling points, and the pixel points above each sampling point are white; The RANSAC algorithm is used to fit a straight line to each sampling point to obtain the inclination angle of the straight line ; The gray image is rotated counterclockwise by degrees; The kmeans algorithm is used to cluster the gray values of all points on the gray image, and the gray values are sorted from small to large, and the minimum, the maximum, and the binarization threshold is calculated according to the following formula : ; In the above formula, K is the number of cluster centers, is the gray value of the i-th cluster center; According to the binarization threshold , the gray image is binarized, the gray value of the pixel point whose gray value is less than is set to 0, and the gray value of other pixel points is set to 1.​​

[0008] In a preferred embodiment, the corresponding verification procedure of the digital electrocardiograph includes: internal calibration voltage verification procedure, input voltage range verification procedure, polarization voltage resistance verification procedure, weighted coefficient error verification procedure, internal noise level verification procedure, amplitude-time parameter measurement verification procedure, amplitude-frequency characteristic verification procedure, time constant verification procedure and common-mode rejection ratio verification procedure.

[0009] In a preferred embodiment, the internal calibration voltage verification procedure includes: S31a: Construct a square wave template image with a period of 10 pixels and an amplitude of 10 pixels and a duty cycle of 0.5; S31b: Template matching the pre-processed output signal image corresponding to the internal calibration voltage verification procedure with the square wave template image to determine all square wave regions; S31c: Extracting the square wave image corresponding to the square wave region, searching for the upper and lower edges of the square wave corresponding to the square wave image using line-by-line scanning method, obtaining the amplitude of the square wave, the left side from top to bottom is the internal calibration voltage signal amplitude of lead I, lead II and lead III , and the right side from top to bottom is the external square wave signal amplitude of lead I, lead II and lead III ; S31d: Calculating the internal calibration voltage error according to the amplitude of the square wave, and comparing it with the standard to determine whether the internal calibration voltage error of the digital electrocardiograph is qualified or not, the calculation method of the internal calibration voltage error is as follows: ; The input voltage range verification procedure includes: S32a: Constructing an ECG signal waveform template image with a period of 33.3 pixels and an amplitude of 25 pixels; S32b: Template matching the pre-processed output signal image corresponding to the input voltage range verification procedure with the ECG signal waveform template image to determine the ECG waveform region; S32c: Extracting the ECG waveform image corresponding to the ECG waveform region, determining the coordinates of the uppermost black pixel point and the lowermost black pixel point using line-by-line scanning method, and calculating the height difference between the two points to determine the ECG signal amplitude of the ECG waveform image; ​S32d: compare the ECG signal amplitude with the regulation standard to determine whether the input voltage range of the digital electrocardiograph is qualified; The polarization voltage test procedure comprises: S33a: search for horizontal straight lines on the preprocessed output signal image corresponding to the polarization voltage test procedure using the Hough transform algorithm, and determine whether the polarization voltage of the digital electrocardiograph is qualified by comparing the height difference between each two adjacent straight lines with the regulation standard, wherein the height difference between each two adjacent straight lines is less than 5 pixels; S33b: calculate the height difference between each two adjacent straight lines, and compare the height difference with the regulation standard to determine whether the polarization voltage of the digital electrocardiograph is qualified; The weighting coefficient error test procedure comprises: S34a: construct two kinds of sinusoidal wave template images with a period of 2.5 pixels, and amplitudes of 30 pixels, 15 pixels, respectively; S34b: perform template matching on the preprocessed output signal image corresponding to the weighting coefficient error test procedure with the two kinds of sinusoidal wave template images respectively to determine all sinusoidal wave regions corresponding to each amplitude; S34c: extract each sinusoidal wave region, search for the peak and trough of the sinusoidal wave in a row-by-row scanning manner to obtain the sinusoidal wave amplitude; S34d: calculate the weighting coefficient error according to the sinusoidal wave amplitude, and compare the weighting coefficient error with the regulation standard to determine whether the weighting coefficient error of the digital electrocardiograph is qualified; The calculation method of the weighting coefficient error is as follows: ; In the above formula, M is the number of leads, is the actual sinusoidal wave amplitude of lead i, is the sinusoidal wave standard amplitude of lead i corresponding to the regulation standard; The internal noise level test procedure comprises: S35a: search for all horizontal straight lines on the preprocessed output signal image corresponding to the internal noise level test procedure using the Hough transform algorithm; S35b: intercept a rectangular region with each straight line as the center and a height of 5 pixels, search for the coordinates of the black pixel points on the uppermost side and the lowermost side of the straight line in a row-by-row scanning manner, and determine the radial height difference ; S35c: calculate the internal noise level according to the maximum radial height difference among all straight lines; ​And compare with the standard, determine the internal noise level of the digital electrocardiograph Whether qualified, internal noise level The calculation method is as follows: ; The amplitude-time parameter measurement verification process comprises: S36a: Construct a periodic ECG signal waveform template image with 33.3 pixels, and the amplitudes are 10 pixels, 20 pixels, 40 pixels, respectively, and are decomposed into P wave part, QRS wave part and T wave part; S36b: Template matching is performed between the preprocessed output signal image corresponding to the amplitude-time parameter measurement verification process and each ECG signal waveform template image, respectively, to determine each ECG waveform region; S36c: Extract each ECG waveform region, and for each ECG waveform region, template matching is performed using the P wave part, QRS wave part and T wave part, respectively, to determine the P wave region, QRS wave region and T wave region; S36d: First derivative is calculated for the P wave region black pixel coordinate position, the left first derivative greater than 1 coordinate point is the P wave starting point, the first coordinate point with derivative 0 is the P wave first peak, the second coordinate point with derivative 0 is the P wave trough, the third coordinate point with derivative 0 is the P wave second peak, and the right last coordinate point with derivative less than -1 is the P wave end point; S36e: First derivative is calculated for the QRS wave region black pixel point coordinate, and the six non-differentiable coordinate points are in turn the Q wave starting point, Q wave trough, R wave first peak, R wave trough, R wave second peak and R wave end point; S36f: First derivative is calculated for the T wave region black pixel point coordinate, the left first non-differentiable coordinate point is the T wave starting point, the right last non-differentiable coordinate point is the T wave end point, and the coordinate point with the smallest radial coordinate is the T wave trough; S36g: Calculate the ECG signal amplitude parameter and time parameter according to the coordinates of P wave, Q wave, R wave and T wave, and compare with the standard to determine whether the amplitude-time parameter of the digital electrocardiograph is qualified; The amplitude-frequency characteristic verification process comprises: S37a: Construct an ECG signal waveform template image with amplitudes of 20 pixels and periods of 50 pixels, 5 pixels, 2.5 pixels, pixels, 1 pixels, pixel, pixel, pixel, pixel, 10 sinusoidal template images of the pixel; S37b: template matching is performed between the preprocessed output signal image corresponding to the amplitude-frequency characteristic calibration process and each of the sinusoidal template images to determine all candidate image regions of sinusoidal waves with 10 different periods; S37c: for each type of sinusoidal wave, the candidate image region with the highest matching degree is taken as a typical region of the sinusoidal wave, and the wave crest and trough of the typical region are searched in a line-by-line scanning manner to obtain the amplitude of each type of sinusoidal wave, which is denoted as ; S37d: the amplitude-frequency characteristic is calculated according to the amplitude of the sinusoidal wave, and is compared with the calibration standard to determine whether the amplitude-frequency characteristic of the digital electrocardiograph is qualified , the calculation method of the amplitude-frequency characteristic is as follows: ; In the above formula, is the maximum value in the amplitudes of all sinusoidal waves, that is, , is the amplitude value of the sinusoidal wave with a period of 2.5 pixels, that is, ; The time constant calibration process comprises: S38a: the Hough transform algorithm is used to search for all vertical straight lines in the preprocessed output signal image corresponding to the time constant calibration process, and straight lines with a length less than 10 pixels are filtered out; S38b: each straight line with a midpoint vertical coordinate difference less than 5 pixels is divided into a group, the horizontal distance value between adjacent two straight lines in the group is counted, and the horizontal distance value less than 10 pixels is filtered out; S38c: each horizontal distance value is sorted, the middle 3 horizontal distance values are retained, and the average horizontal distance d is obtained by averaging; S38d: the average horizontal distance d is converted into the time constant T, and is compared with the calibration standard to determine whether the time constant of the digital electrocardiograph is qualified, the conversion method is as follows: ; The common-mode rejection ratio calibration process comprises: S39a: a 10 pixel-long and 30 A rectangular window of the pixel, using the rectangular window to scan the output signal image of the digital electrocardiograph in 5 The step distance scanning common mode rejection ratio test procedure corresponds to the pretreated output signal image, the proportion of black pixels in the current window is counted, and if the proportion of black pixels is greater than 60%, the uppermost and lowermost black pixel coordinates in the window are searched by using the row-by-row scanning mode and the height difference is calculated to obtain a height difference set Wherein X is the number of scans; S39b: The maximum value in the height difference set is taken to calculate the common mode rejection ratio CMRR, and the common mode rejection ratio CMRR of the digital electrocardiograph is determined by comparing with the test standard, and the calculation method of the common mode rejection ratio CMRR is as follows: .

[0010] In a preferred embodiment, the output signal image is a scanning image obtained by scanning the printed paper tape output by the digital electrocardiograph in the current test procedure by using a high-definition scanner.

[0011] In a preferred embodiment, the determination step of the test procedure comprises: According to the preset test procedure sequence, the test procedure corresponding to the current digital electrocardiograph is determined, and the test procedure steps corresponding to each test procedure are sequentially executed; or, According to the test procedure type input by the user, each test procedure step corresponding to the test procedure type is executed.

[0012] Compared with the prior art, the full-process test method of the digital electrocardiograph provided by the application has the following advantages: The full-process test method of the digital electrocardiograph provided by the application first obtains a pixel-millimeter scale through steel ruler image analysis, analyzes the inclination angle of the output signal image of the digital electrocardiograph by using the RANSAC algorithm and corrects it, simultaneously obtains a threshold binarization threshold by using the kmeans algorithm, realizes adaptive binarization of the color scanning image, has higher robustness, and designs an automatic test method based on digital image processing for each test procedure related to the digital electrocardiograph, so that full-process test of the digital electrocardiograph can be realized, and the full-process test efficiency and test accuracy of the digital electrocardiograph are improved. BRIEF DESCRIPTION OF DRAWINGS

[0013] The drawings incorporated into the specification and forming a part thereof show embodiments consistent with the present application and, together with the specification, serve to explain the principles of the application.

[0014] Figure 1 is an implementation environment schematic diagram of a full-process test method of a digital electrocardiograph according to an exemplary embodiment.

[0015] Figure 2 The present invention is a flowchart of a method for full-process verification of a digital electrocardiograph according to an exemplary embodiment.

[0016] Figure 3 The figure is a schematic diagram of an output signal image corresponding to a printing paper tape according to an exemplary embodiment.

[0017] Figure 4 The figure is a schematic diagram of an output image obtained after preprocessing an output signal image according to an exemplary embodiment.

[0018] Figure 5 The figure is a schematic diagram of an image of an output signal after preprocessing input in an internal calibration voltage verification process according to an exemplary embodiment.

[0019] Figure 6 It is a schematic diagram of a calibration output image corresponding to an internal calibration voltage calibration process according to an exemplary embodiment.

[0020] Figure 7 The figure is a schematic diagram of an image of a pre-processed output signal input in an input voltage range verification process according to an exemplary embodiment.

[0021] Figure 8 The figure is a schematic diagram of a calibration output image corresponding to an input voltage range calibration process according to an exemplary embodiment.

[0022] Figure 9 It is a schematic diagram of an image of an output signal after preprocessing input in a polarization resistance voltage verification process according to an exemplary embodiment.

[0023] Figure 10 It is a schematic diagram of a test output image corresponding to a polarization resistance voltage test process according to an exemplary embodiment.

[0024] Figure 11 The figure is a schematic diagram of an image of a pre-processed output signal input into a weighted coefficient error detection process according to an exemplary embodiment.

[0025] Figure 12 It is a schematic diagram of a calibration output image corresponding to a weighted coefficient error calibration process according to an exemplary embodiment.

[0026] Figure 13 The figure is a schematic diagram of an image of a pre-processed output signal input into an internal noise level detection process according to an exemplary embodiment.

[0027] Figure 14 The figure is a schematic diagram of a calibration output image corresponding to an internal noise level calibration process according to an exemplary embodiment.

[0028] Figure 15 is a schematic diagram of a pre-processed output signal image input in a magnitude-time parameter measurement verification procedure according to an example embodiment.

[0029] Figure 16 is a schematic diagram of a verification output image corresponding to a magnitude-time parameter measurement verification procedure according to an example embodiment.

[0030] Figure 17 is a schematic diagram of a pre-processed output signal image input in a magnitude-frequency characteristic verification procedure according to an example embodiment.

[0031] Figure 18 is a schematic diagram of a verification output image corresponding to a magnitude-frequency characteristic verification procedure according to an example embodiment.

[0032] Figure 19 is a schematic diagram of a pre-processed output signal image input in a time constant verification procedure according to an example embodiment.

[0033] Figure 20 is a schematic diagram of a verification output image corresponding to a time constant verification procedure according to an example embodiment.

[0034] Figure 21 is a schematic diagram of a pre-processed output signal image input in a common-mode rejection ratio verification procedure according to an example embodiment.

[0035] Figure 22 is a schematic diagram of a verification output image corresponding to a common-mode rejection ratio verification procedure according to an example embodiment. DETAILED DESCRIPTION

[0036] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be described in detail below with reference to specific examples (but not limited to the examples). Obviously, the described examples are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0037] In order to facilitate understanding, the meanings of the English abbreviations involved in the embodiments of the present application are explained as follows: ECG: electrocardiogram, refers to an electrocardiogram.

[0038] RANSAC: Random Sample Consensus, a random sample consensus algorithm, which is used to estimate the fitting model of the sample by using an iterative method.

[0039] Figure 1 is a full-process verification method for a digital electrocardiograph according to an example embodiment of the present application, as shown in Figure 1 The implementation environment includes at least one digital electrocardiograph 3 to be verified, a high-definition scanner 2, and a server 1.

[0040] The server can be a tablet computer, a mobile phone, a desktop computer, or the like.

[0041] The digital electrocardiograph 3 inputs a standard signal corresponding to the current verification process according to the standard verification rule corresponding to the digital electrocardiograph, and outputs the output signal in the form of a printed paper tape 4. The high-definition scanner 2 scans the printed paper tape 4 to obtain the corresponding output signal image, and transmits the output signal image to the server 1 through wired or wireless signal transmission. The server 1 analyzes the output signal image to detect whether the functional parameters corresponding to each verification process of the digital electrocardiograph meet the corresponding verification rule standards. When the functional parameters corresponding to each verification process are detected to meet the corresponding verification rule standards, the comprehensive verification result of the digital electrocardiograph is determined to be qualified.

[0042] Figure 2 is a method flowchart of a full-process verification method for a digital electrocardiograph according to an example embodiment of the present application, as shown in Figure 2 The full-process verification method for the digital electrocardiograph includes: S10: obtaining a standard steel ruler image corresponding to the digital electrocardiograph, and determining a pixel-millimeter scale corresponding to the standard steel ruler image.

[0043] S20: for each verification process corresponding to the digital electrocardiograph, obtaining an output signal image corresponding to the verification process, and pre-processing the output signal image.

[0044] S30: performing image analysis on each pre-processed output signal image according to the pixel-millimeter scale, and calculating signal parameters, respectively. The digital electrocardiograph whose each signal parameter meets the corresponding verification rule standard is determined to be qualified.

[0045] In a preferred embodiment, S10 includes the following steps: image scanning of a standard steel ruler corresponding to the digital electrocardiograph to obtain a standard steel ruler image corresponding to the standard steel ruler; determining the wide side of the standard steel ruler image by Hough transform, calculating the number of pixels p in the wide side of the standard steel ruler image, and calculating the pixel-millimeter scale corresponding to the standard steel ruler image according to the following formula ​ ; In the formula, w is the actual length of the standard steel ruler wide side, in millimeters.

[0046] In a preferred embodiment, the step of preprocessing the output signal image in S20 comprises: graying the output signal image to obtain a gray image; randomly selecting N black pixel points in the gray image as sampling points, and the pixel points above each sampling point are white; using the RANSAC algorithm to fit a straight line to each sampling point to obtain the inclination angle of the straight line ; counterclockwise rotating the gray image by degrees; using the kmeans algorithm to cluster the gray values of all points on the gray image, sorting them from small to large, and recording the minimum value, the maximum value, and calculating the binary threshold value according to the following formula : ; In the formula, K is the number of cluster centers, is the gray value of the i-th cluster center; binary processing the gray image according to the binary threshold value , setting the gray value of the pixel points with a gray value less than to 0, and setting the gray value of the other pixel points to 1.

[0047] In a preferred embodiment, the output signal image is a scanning image obtained by scanning the printed paper tape output by the digital electrocardiograph in the current calibration process using a high-definition scanner.

[0048] For example, a schematic diagram of an output signal image corresponding to a printed paper tape according to an embodiment of the present application can be as shown in Figure 3 , and a schematic diagram of the output image obtained after the preprocessing step of the output signal image can be as shown in Figure 4 . Figure 3 , 4 As can be seen from the comparison, , the present embodiment can effectively remove the background grid and color of the scanning image corresponding to the printed paper tape output by the digital electrocardiograph in the current calibration process without damaging the signal waveform of the digital electrocardiograph. After correcting the inclination of the scanning image, the scanning image can be used as input image data for the subsequent calibration process, making the results of the subsequent calibration process more accurate.

[0049] In a preferred embodiment, the calibration process corresponding to the digital electrocardiograph includes: internal calibration voltage calibration process, input voltage range calibration process, polarization resistance voltage calibration process, weighting coefficient error calibration process, internal noise level calibration process, amplitude-time parameter measurement calibration process, amplitude-frequency characteristic calibration process, time constant calibration process and common mode rejection ratio calibration process.

[0050] In a preferred embodiment, the internal calibration voltage verification process includes: S31a: Construction period is 10 Pixels, steps of 10 Pixels, square wave template image with a duty cycle of 0.5.

[0051] S31b: performing template matching between the pre-processed output signal image corresponding to the internal calibration voltage verification process and the square wave template image to determine all square wave regions.

[0052] For example, the schematic diagram of the pre-processed output signal image input in the internal calibration voltage verification process shown in the embodiment of the present invention can be as follows: Figure 5 shown.

[0053] S31c: Extract the square wave image corresponding to the square wave area, use progressive scanning to search for the upper and lower edges of the square wave corresponding to the square wave image, and obtain the amplitude of the square wave. The left side, from top to bottom, is the internal calibration voltage signal amplitude of lead I, lead II, and lead III. , from top to bottom on the right are the external square wave signal amplitudes of Lead I, Lead II, and Lead III .

[0054] Figure 5 The corresponding test output image diagram is as follows: Figure 6 As shown, compared Figure 5 、 6 It can be seen that this embodiment can accurately search for the waveforms of leads I, II, and III from the output signal image and measure their signal amplitudes.

[0055] S31d: Calculate the internal calibration voltage error based on the amplitude of the square wave and compare it with the inspection standard to determine the internal calibration voltage error of the digital electrocardiograph Whether qualified.

[0056] Internal calibration voltage error The calculation method is as follows: ; The basis for determining whether the internal calibration voltage error δC of the digital electrocardiograph is qualified can be: the calculated internal calibration voltage error whether the input voltage range meets the preset internal standard voltage error range of the standard.

[0057] The input voltage range verification procedure includes: S32a: constructing a cycle of 33.3 pixels, and the amplitude is 25 The ECG signal waveform template image of the pixel.

[0058] S32b: performing template matching on the preprocessed output signal image corresponding to the input voltage range verification procedure and the ECG signal waveform template image to determine the ECG waveform region.

[0059] Exemplarily, a preprocessed output signal image input in an input voltage range verification procedure shown in an embodiment of the present application can be as shown in Figure 7 .

[0060] S32c: extracting the ECG waveform image corresponding to the ECG waveform region, determining the uppermost black pixel point coordinate and the lowermost black pixel point coordinate in a row-by-row scanning manner, and calculating the height difference between the two points to determine the ECG signal amplitude of the ECG waveform image.

[0061] Figure 7 The corresponding verification output image schematic diagram is as shown in Figure 8 , wherein Figure 8 Each number in Figure 7 , 8 It can be seen that the target ECG signal waveform can be accurately searched from the paper strip image, and the ECG signal amplitude can be determined.

[0062] S32d: comparing the ECG signal amplitude with the standard to determine whether the input voltage range of the digital electrocardiograph is qualified.

[0063] The basis for determining whether the input voltage range of the digital electrocardiograph is qualified can be whether the calculated input voltage range corresponding to the ECG signal amplitude meets the preset input voltage range of the standard. If it meets, it is qualified, and if it does not meet, it is unqualified.

[0064] The polarization voltage verification procedure includes: S33a: using the Hough transform algorithm to search for horizontal straight lines on the preprocessed output signal image corresponding to the polarization voltage verification procedure, and dividing the straight lines with a horizontal coordinate value difference less than 5 pixels into a group.

[0065] Exemplarily, a preprocessed output signal image input in a polarization voltage verification procedure shown in an embodiment of the present application can be as shown inFigure 9 as shown.

[0066] Figure 9 The corresponding test output image schematic diagram is shown in Figure 10 , and it can be known that the embodiment can accurately determine the output waveform of each lead and judge the waveform baseline change when the input signal electrode is reversed. Figure 9 , 10

[0067] S33b: Calculate the height difference between each group of adjacent two straight lines, and compare with the inspection standard to determine whether the polarization voltage of the digital electrocardiograph is qualified.

[0068] The determination of whether the polarization voltage of the digital electrocardiograph is qualified can be that whether the polarization voltage corresponding to the height difference between each group of adjacent two straight lines calculated is consistent with the preset polarization voltage of the inspection standard. If it is consistent, it is qualified, and if it is not consistent, it is not qualified.

[0069] The weighting coefficient error test process comprises: S34a: Construct two kinds of sinusoidal wave template images with a period of 2.5 pixels and amplitudes of 30 pixels and 15 pixels, respectively.

[0070] S34b: Template matching is performed between the preprocessed output signal image corresponding to the weighting coefficient error test process and the two kinds of sinusoidal wave template images, respectively, to determine all sinusoidal wave regions corresponding to each amplitude.

[0071] For example, the preprocessed output signal image schematic diagram input in a kind of weighting coefficient error test process shown in the embodiment of the application can be as shown in Figure 11 .

[0072] Figure 11 The corresponding test output image schematic diagram is shown in Figure 12 , and it can be known that the embodiment can accurately determine the output waveform of each lead and judge the waveform baseline change when the input signal electrode is reversed. Figure 11 , 12

[0073] S34c: Extract each sinusoidal wave region, search the peak and trough of the sinusoidal wave in a row-by-row scanning manner, and obtain the sinusoidal wave amplitude.

[0074] S34d: Calculate the weighting coefficient error according to the sinusoidal wave amplitude , and compare with the inspection standard to determine whether the weighting coefficient error of the digital electrocardiograph is qualified.

[0075] Weighting coefficient error​​ The calculation method is as follows: .

[0076] In the above formula, M is the number of leads, is the actual sine wave amplitude of lead i, It is the standard amplitude of the sine wave of lead i corresponding to the inspection standard.

[0077] The basis for determining whether the weighted coefficient error of the digital electrocardiograph is qualified can be: the calculated weighted coefficient error Whether it complies with the weighted coefficient error preset in the inspection regulations. If it does, it is qualified; if not, it is unqualified.

[0078] The internal noise level verification process includes: S35a: Using the Hough transform algorithm, search for all horizontal straight lines on the pre-processed output signal image corresponding to the internal noise level verification process.

[0079] For example, the schematic diagram of the pre-processed output signal image input in the internal noise level detection process shown in the embodiment of the present invention can be as follows: Figure 13 shown.

[0080] S35b: intercept the searched straight lines as the center, with a height of 5 The rectangular area of ​​pixels is scanned line by line to search for the coordinates of the black pixels at the top and bottom of the line to determine the radial height difference. .

[0081] For example, the schematic diagram of the pre-processed output signal image input in the internal noise level detection process shown in the embodiment of the present invention can be as follows: Figure 13 As shown, compared Figure 13 、 14 It can be seen that this embodiment can accurately find the lead with the largest internal noise.

[0082] S35c: Based on the maximum radial height difference among all straight lines Calculating the internal noise level and compare it with the inspection standards to determine the internal noise level of the digital electrocardiograph Whether qualified.

[0083] Internal noise level The calculation method is as follows: .

[0084] Wherein, the internal noise level of the digital electrocardiograph is determined The basis for qualification can be: the calculated internal noise level whether the internal noise level meets the preset internal noise level of the inspection regulation, if yes, the ECG signal is qualified, if not, the ECG signal is unqualified.

[0085] The amplitude-time parameter measurement inspection procedure comprises: S36a: constructing a cycle of 33.3 pixels, and the amplitudes are 10 pixels, 20 pixels, 40 pixels, respectively.

[0086] S36b: performing template matching between the preprocessed output signal image corresponding to the amplitude-time parameter measurement inspection procedure and each ECG signal waveform template image, respectively, to determine each ECG waveform region.

[0087] Exemplarily, a schematic diagram of the preprocessed output signal image input in the amplitude-time parameter measurement inspection procedure shown in the embodiment of the present application can be as shown in Figure 15 .

[0088] S36c: extracting each ECG waveform region, and for each ECG waveform region, performing template matching with the P wave part, the QRS wave part and the T wave part, respectively, to determine the P wave region, the QRS wave region and the T wave region.

[0089] Figure 15 A corresponding inspection output image schematic diagram is as shown in Figure 16 , Figure 16 The numbers in the diagram are the confidence degrees of the signal waveform template matching. It can be known by comparing Figure 15 , 16 that the embodiment can accurately locate the coordinates of each key point in the ECG signal.

[0090] S36d: calculating the first derivative of the black pixel coordinate position of the P wave region, and the leftmost coordinate point with a derivative greater than 1 is the P wave starting point, the first coordinate point with a derivative of 0 is the first P wave peak, the second coordinate point with a derivative of 0 is the P wave valley, the third coordinate point with a derivative of 0 is the second P wave peak, and the rightmost coordinate point with a derivative less than -1 is the P wave ending point.

[0091] S36e: calculating the first derivative of the black pixel coordinate of the QRS wave region, and the six non-differentiable coordinate points are the Q wave starting point, the Q wave valley, the first R wave peak, the R wave valley, the second R wave peak and the R wave ending point, in sequence.

[0092] S36f: first derivative of the black pixel point coordinates in the T wave region is calculated, the first non-derivable coordinate point on the left side is the T wave starting point, the last non-derivable coordinate point on the right side is the T wave ending point, and the coordinate point with the smallest radial coordinate is the T wave trough.

[0093] S36g: the ECG signal amplitude parameters and time parameters are calculated according to the coordinates of the P wave, Q wave, R wave and T wave, and compared with the inspection standard to determine whether the amplitude-time parameters of the digital electrocardiograph are qualified.

[0094] The determination of whether the amplitude-time parameters of the digital electrocardiograph are qualified can be based on whether the calculated ECG signal amplitude parameters and time parameters meet the ECG signal amplitude parameters and time parameters preset by the inspection standard. If they meet, the parameters are qualified, and if they do not meet, the parameters are unqualified.

[0095] The amplitude-frequency characteristic verification process includes: S37a: 10 sinusoidal wave template images with amplitudes of 20 pixels, periods of 50 pixels, 5 pixels, 2.5 pixels, pixels, 1 pixels, pixels, pixels, pixels, pixels, pixels are constructed.

[0096] S37b: the preprocessed output signal images corresponding to the amplitude-frequency characteristic verification process are respectively template matched with each of the sinusoidal wave template images to determine all candidate image regions of sinusoidal waves with 10 different periods.

[0097] Exemplarily, a schematic diagram of a preprocessed output signal image input in an amplitude-frequency characteristic verification process shown in an embodiment of the present application is shown in Figure 17 . Figure 17 A corresponding verification output image schematic diagram is shown in Figure 18 . By comparing Figure 17 , 18 , it can be known that the embodiment can accurately locate waveforms with different periods.

[0098] S37c: for each type of sinusoidal wave, the candidate image region with the highest matching degree is taken as a typical region of the sinusoidal wave, and the wave peak and wave trough of the typical region are searched in a line-by-line scanning manner to obtain the amplitude of each type of sinusoidal wave, which is respectively denoted as .

[0099] S37d: the amplitude-frequency characteristic is calculated according to the amplitudes of the sinusoidal waves and compare it with the inspection standards to determine the amplitude-frequency characteristics of the digital electrocardiograph Whether it is qualified, amplitude-frequency characteristics The calculation method is as follows: ; In the above formula, is the maximum value among all the sine wave amplitudes, that is , The period is 2.5 The amplitude value of the pixel's sine wave, that is .

[0100] Wherein, the amplitude-frequency characteristic of the digital electrocardiograph is determined The basis for qualification can be: the calculated amplitude-frequency characteristics Whether it meets the amplitude-frequency characteristics preset in the inspection standards, if it does, it is qualified, if not, it is unqualified.

[0101] The time constant verification process includes: S38a: Use the Hough transform algorithm to search for all vertical lines in the output signal image after preprocessing corresponding to the time constant verification process, and filter out those with a length less than 10 A straight line of pixels.

[0102] S38b: Set the vertical coordinate difference of the midpoint to be less than 5 Each straight line of the pixel is divided into a group, and the horizontal distance between two adjacent straight lines in the group is counted, and the distances less than 10 are filtered out. The horizontal distance value in pixels.

[0103] S38c: Sort the horizontal distance values, retain the middle three horizontal distance values ​​and take the average to obtain the average horizontal distance d.

[0104] S38d: Convert the horizontal average distance d into a time constant T, and compare it with the inspection standard to determine whether the time constant of the digital electrocardiograph is qualified.

[0105] The conversion method is as follows: .

[0106] For example, the schematic diagram of the pre-processed output signal image input in the time constant verification process shown in the embodiment of the present invention can be as follows: Figure 19 As shown, the corresponding verification output image is as follows Figure 20 As shown, compared Figure 19 、 20 It can be seen that this embodiment can accurately calculate the time constant of each lead.

[0107] The criterion for determining whether the time constant T of the digital electrocardiograph is qualified can be whether the calculated time constant T meets a preset time constant of a test regulation standard, and if yes, the digital electrocardiograph is qualified, and if not, the digital electrocardiograph is unqualified.

[0108] The common-mode rejection ratio test procedure comprises: S39a: a rectangular window with a length of 10 pixels and a height of 30 pixels is constructed, and the preprocessed output signal image corresponding to the common-mode rejection ratio test procedure is scanned by using the rectangular window with a step distance of 5 pixels, the proportion of black pixels in the current window is counted, and if the proportion of black pixels is greater than 60%, the uppermost and lowermost black pixel coordinates in the window are searched by using the line-by-line scanning method and the height difference is calculated to obtain a height difference set , wherein X is the number of scans.

[0109] S39b: the maximum value in the height difference set is taken to calculate the common-mode rejection ratio CMRR, and the common-mode rejection ratio CMRR is compared with a test regulation standard to determine whether the common-mode rejection ratio CMRR of the digital electrocardiograph is qualified.

[0110] The common-mode rejection ratio CMRR is calculated according to the following formula: .

[0111] For example, the preprocessed output signal image input in a common-mode rejection ratio test procedure shown in an embodiment of the present application is schematically shown in Figure 21 , and the corresponding test output image is schematically shown in Figure 22 , Figure 22 , wherein the numbers marked in the figure are the waveform heights detected in the window with a black pixel proportion greater than 60%. Figure 21 , 22 It can be seen that the embodiment can accurately measure the amplitudes of the output waveforms of each lead, so as to identify the maximum local amplitude and test the common-mode rejection ratio.

[0112] The criterion for determining whether the common-mode rejection ratio CMRR of the digital electrocardiograph is qualified can be whether the calculated common-mode rejection ratio CMRR meets a preset common-mode rejection ratio of a test regulation standard, and if yes, the digital electrocardiograph is qualified, and if not, the digital electrocardiograph is unqualified.

[0113] In a preferred embodiment, the determining step of the test procedure comprises: (A) determining the test procedure corresponding to the digital electrocardiograph according to a preset test procedure sequence, and sequentially executing the test procedure steps corresponding to each test procedure. Or, (B) executing the test procedure steps corresponding to each test procedure according to the test procedure type input by a user.

[0114] By performing the determining step (A), the embodiment of the present application can perform automatic and efficient full-process verification work on the digital electrocardiograph; by performing the determining step (B), the embodiment of the present application can realize automatic and efficient verification of multiple verification processes of specific types of the digital electrocardiograph.

[0115] In summary, the full-process verification method of the digital electrocardiograph provided by the present application firstly obtains a pixel-millimeter scale through steel ruler image analysis, analyzes the inclination angle of the digital electrocardiograph output signal image through the RANSAC algorithm and corrects it, and simultaneously obtains a threshold value for threshold binaryzation through the kmeans algorithm, realizes adaptive binaryzation of the color scanning image, has higher robustness, and designs an automatic verification method based on digital image processing for each verification process related to the digital electrocardiograph, so as to realize full-process verification of the digital electrocardiograph and improve the full-process verification efficiency and verification accuracy of the digital electrocardiograph.

[0116] Although the foregoing has been a detailed description of the present application, modifications and improvements can be made to it on the basis of what has been disclosed and described, which will be apparent to those skilled in the art. Therefore, these modifications or improvements made on the basis of not deviating from the spirit of the present application shall all fall within the scope of the present application.

[0117] Other embodiments of the present application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. It is intended that the present application cover any and all variations of the application that come within the scope of the present application, along with all equivalents thereof. It is intended that the present application not be limited to the specific structures disclosed and the operation thereof, but that claims be afforded the full scope consistent with the language of the claims.

Claims

1. A full-process calibration method for a digital electrocardiograph, characterized in that: The whole-process calibration method comprises: S10: obtaining a standard steel ruler image corresponding to a digital electrocardiograph, and determining a pixel-millimeter scale corresponding to the standard steel ruler image according to the standard steel ruler image; S20: for each calibration process corresponding to the digital electrocardiograph, obtaining an output signal image corresponding to the calibration process, and pre-processing the output signal image; S30: performing image analysis on each pre-processed output signal image according to the pixel-millimeter scale, and respectively calculating signal parameters, comparing each calculated signal parameter with a corresponding regulation standard, and determining the digital electrocardiograph as qualified if each signal parameter meets the corresponding regulation standard.

2. The method for full procedure verification of a digital electrocardiograph according to claim 1, wherein, S10 comprises the following steps: S11: performing image scanning on the standard steel ruler corresponding to the digital electrocardiograph to obtain a standard steel ruler image corresponding to the standard steel ruler; The width of the standard steel ruler image is determined by the Hough transform, the number of pixels p in the width of the standard steel ruler image is calculated, and the pixel-millimeter scale corresponding to the standard steel ruler image is calculated according to the following formula : ； In the formula, w is the actual length of the wide side of the standard steel ruler, and the unit is millimeter.

3. The method for full procedure verification of a digital electrocardiograph according to claim 1, wherein, The pre-processing step of the output signal image in S20 comprises: S21: performing gray-scale processing on the output signal image to obtain a gray-scale image; S22: randomly selecting N black pixel points in the gray-scale image as sampling points, and the pixel points above each sampling point are white; The RANSAC algorithm is used to fit a straight line to each sample point to obtain the straight line inclination angle ; rotating the grayscale image counterclockwise degrees; The gray scale values of all points on the gray scale image are clustered using a kmeans algorithm, sorted from small to large, and recorded as minimum, maximum, and the binary threshold value is calculated according to the following formula : ； In the above formula, K is the number of cluster centers, is the gray value of the i-th cluster center; According to the binarization threshold The gray image is binarized, and the pixel points with a gray value less than are set to 0, and other pixel points are set to 1.

4. The method for full procedure verification of a digital electrocardiograph according to claim 2, characterized in that, The calibration processes corresponding to the digital electrocardiograph comprise: an internal calibration voltage calibration process, an input voltage range calibration process, a polarization voltage resistance calibration process, a weighted coefficient error calibration process, an internal noise level calibration process, an amplitude-time parameter measurement calibration process, an amplitude-frequency characteristic calibration process, a time constant calibration process, and a common-mode rejection ratio calibration process.

5. The method for full procedure verification of a digital electrocardiograph according to claim 4, characterized in that, The internal calibration voltage calibration process comprises: S31a: Construct a period of 10 Pixels, amplitude of 10 Pixels, square wave template image with a duty cycle of 0.5; S31b: performing template matching on the pre-processed output signal image corresponding to the internal calibration voltage calibration process and the square wave template image to determine all square wave regions; S31c: extracting the square wave image corresponding to the square wave region, searching the upper edge and the lower edge of the square wave corresponding to the square wave image in a line-by-line scanning manner, obtaining the amplitude of the square wave, the left side being the internal reference voltage signal amplitude of lead I, lead II and lead III from top to bottom in turn , the right side being the external square wave signal amplitude of lead I, lead II and lead III from top to bottom in turn ; S31d: calculating the internal calibration voltage error according to the amplitude of the square wave and comparing with the inspection standard to determine whether the internal calibration voltage error of the digital electrocardiograph is qualified and comparing with the inspection standard to determine whether the internal calibration voltage error of the digital electrocardiograph is qualified The calculation method of the internal calibration voltage error is as follows: ； The input voltage range calibration process comprises: S32a: Constructed period is 33.3 Pixels, amplitude is 25 ECG signal waveform template image of pixels; S32b: performing template matching on the pre-processed output signal image corresponding to the input voltage range calibration process and the ECG signal waveform template image to determine an ECG waveform region; S32c: extracting an ECG waveform image corresponding to the ECG waveform region, determining the coordinates of the uppermost black pixel point and the lowermost black pixel point by using a line-by-line scanning method, and calculating the height difference between the two points to determine the ECG signal amplitude of the ECG waveform image; S32d: comparing the ECG signal amplitude with the regulation standard to determine whether the input voltage range of the digital electrocardiograph is qualified; The polarization voltage resistance calibration process comprises: S33a: search for horizontal straight lines on the preprocessed output signal image corresponding to the polarization withstand voltage test procedure using the Hough transform algorithm, and group the horizontal coordinate value difference less than 5 The straight lines of the pixels are grouped; S33b: calculating the height difference between each pair of adjacent straight lines, and comparing the height difference with the regulation standard to determine whether the polarization voltage resistance of the digital electrocardiograph is qualified; The weighted coefficient error calibration process comprises: S34a: Constructed period is 2.5 pixels, amplitude of 30 pixels, 15 two sinusoidal wave template images of 15 pixels S34b: performing template matching on the pre-processed output signal image corresponding to the weighted coefficient error calibration process and the two kinds of sine wave template images to determine all sine wave regions corresponding to each amplitude; S34c: extracting each sine wave region, searching for the peaks and troughs of the sine wave by using a line-by-line scanning method, and obtaining the sine wave amplitude; S34d: calculating a weighting coefficient error according to the sine wave amplitude and comparing with the inspection standard to determine whether the weighting coefficient error of the digital electrocardiograph is qualified and comparing with the inspection standard to determine whether the weighting coefficient error of the digital electrocardiograph is qualified The calculation method of the weighting coefficient error is as follows: ； In the above formula, M is the number of leads, is the actual sinusoidal amplitude of lead i, is the sinusoidal standard amplitude of lead i corresponding to the detection criterion. The internal noise level calibration process comprises: S35a: using the Hough transform algorithm to search all horizontal straight lines on the preprocessed output signal image corresponding to the internal noise level calibration process; S35b: intercept with the center of each straight line searched, height 5 The rectangular area of the pixel, using line-by-line scanning method to search the coordinates of the uppermost and lowermost black pixel points of the straight line, to determine the radial height difference ; S35c: the largest radial height difference among all straight lines calculating the internal noise level and comparing with the inspection standard to determine whether the internal noise level of the digital electrocardiograph is qualified whether the internal noise level is qualified The calculation method of the internal noise level is as follows: ； The amplitude-time parameter measurement calibration process comprises: S36a: Constructing a period of 33.3 pixels, amplitude of 10 pixels, 20 pixels, 40 ECG signal waveform template image of 40 pixels, and is respectively decomposed into P wave part, QRS wave part, T wave part; S36b: performing template matching on the preprocessed output signal image corresponding to the amplitude-time parameter measurement calibration process with each ECG signal waveform template image respectively to determine each ECG waveform region; S36c: extracting each ECG waveform region, and performing template matching on each ECG waveform region with a P-wave part, a QRS wave part and a T-wave part respectively to determine a P-wave region, a QRS wave region and a T-wave region; S36d: calculating a first derivative of the black pixel coordinate position of the P-wave region, and taking the leftmost first coordinate point with a derivative greater than 1 as a P-wave starting point, the first coordinate point with a derivative of 0 as a P-wave first wave peak, the second coordinate point with a derivative of 0 as a P-wave wave trough, the third coordinate point with a derivative of 0 as a P-wave second wave peak, and the rightmost last coordinate point with a derivative less than -1 as a P-wave ending point; S36e: calculating a first derivative of the black pixel coordinate of the QRS wave region, and taking the six non-derivable coordinate points in turn as a Q-wave starting point, a Q-wave wave trough, a R-wave first wave peak, a R-wave wave trough, a R-wave second wave peak and a R-wave ending point; S36f: calculating a first derivative of the black pixel coordinate of the T-wave region, and taking the leftmost first non-derivable coordinate point as a T-wave starting point, the rightmost last non-derivable coordinate point as a T-wave ending point, and the coordinate point with the smallest radial coordinate as a T-wave wave trough; S36g: calculating ECG signal amplitude parameters and time parameters according to the coordinates of the P-wave, the Q-wave, the R-wave and the T-wave, and comparing the parameters with the calibration standard to determine whether the amplitude-time parameters of the digital electrocardiograph are qualified; The amplitude-frequency characteristic calibration process comprises: S37a: Construct 20 pixels, period 50 pixels, 5 pixels, 2.5 pixels, pixels, 1 pixels, pixels, pixels, pixels, 10 sinusoidal wave template images of 10 pixels S37b: performing template matching on the preprocessed output signal image corresponding to the amplitude-frequency characteristic calibration process with each of the sine wave template images to determine all candidate image regions of the 10 kinds of sine waves with different periods; S37c: for each kind of sine wave, taking the candidate image region with the highest matching degree as a typical region of the kind of sine wave, and searching the wave peak and the wave trough of the typical region in a line-by-line scanning manner to obtain the amplitude of each kind of sine wave, and recording the amplitudes as ； S37d: Calculate the amplitude-frequency characteristic based on the amplitude of the sine wave and compare it with the inspection standards to determine the amplitude-frequency characteristics of the digital electrocardiograph Whether it is qualified, amplitude-frequency characteristics The calculation method is as follows: ； In the above formula, is the maximum value among the amplitudes of all sinusoidal waves, i.e. , is the period of 2.5 the amplitude value of the sinusoidal wave of the pixel, i.e. ; The time constant calibration process comprises: S38a: Using the Hough transform algorithm to search all vertical straight lines in the pre-processed output signal image corresponding to the time constant verification procedure, and filter out straight lines with a length less than 10 straight lines of pixels; S38b: the midpoint vertical coordinate difference value is less than 5 Each straight line of the pixel is divided into a group, the horizontal distance value between adjacent two straight lines in the group is counted, and the value less than 10 is filtered out Horizontal distance value of the pixel; S38c: sorting the horizontal distance values, retaining the middle three horizontal distance values and averaging to obtain an average horizontal distance d; S38d: converting the average horizontal distance d into a time constant T, and comparing the time constant T with the calibration standard to determine whether the time constant of the digital electrocardiograph is qualified, and the conversion method is as follows: ； The common mode rejection ratio calibration process comprises: S39a: Constructing a 10 pixels, 30 pixels, using the rectangular window to scan 5 pixels, the output signal image corresponding to the pre-processed output signal image of the step distance scanning common-mode rejection ratio test procedure, counting the proportion of black pixels in the current window, if the proportion of black pixels is greater than 60%, using the row-by-row scanning method to search for the uppermost and lowermost black pixel coordinates in the window and calculate the height difference, obtaining a height difference set where X is the number of scans; S39b: taking the maximum value in the height difference set to calculate the common mode rejection ratio CMRR, and comparing the common mode rejection ratio CMRR with the calibration standard to determine whether the common mode rejection ratio CMRR of the digital electrocardiograph is qualified, and the calculation method of the common mode rejection ratio CMRR is as follows: 。 6. The method for full procedure verification of a digital electrocardiograph according to claim 1, wherein, The output signal image is a scanning image obtained by scanning the printed paper tape output by the digital electrocardiograph in the current calibration process by a high-definition scanner.

7. The method for full procedure verification of a digital electrocardiograph according to claim 1, characterized in that, The determination step of the calibration process comprises: According to the preset calibration procedure sequence, determine the calibration procedure corresponding to the digital electrocardiograph, and sequentially execute the calibration procedure steps corresponding to each calibration procedure. According to the calibration procedure type input by the user, execute each calibration procedure step corresponding to the calibration procedure type.

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