java后端生成心电图-jfreechart

用jfreechart生成心电图

先上成功的图片

上代码

1.导入包

  implementation 'org.jfree:jfreechart:1.5.4'implementation 'org.jfree:jcommon:1.0.24'

2.实现代码

对数据进行滤波

转换单位

package com.shinrun.infrastructure.util;import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;public class ECGDataConverter {/*** 将原始数据转换为mV单位的数据* @param rawData 原始数据数组* @param scaleFactor 比例因子(20000对应1mV)* @return 转换后的数据数组(单位mV)*/public static double[] convertToMillivolts(double[] rawData, double scaleFactor) {double[] convertedData = new double[rawData.length];for (int i = 0; i < rawData.length; i++) {convertedData[i] = rawData[i] / scaleFactor;}return convertedData;}/*** 将原始数据转换为微伏(uV)单位的数据* @param rawData 原始数据数组* @param scaleFactor 比例因子(20000对应1mV)* @return 转换后的数据数组(单位uV)*/public static double[] convertToMicrovolts(double[] rawData, double scaleFactor) {double[] convertedData = new double[rawData.length];for (int i = 0; i < rawData.length; i++) {convertedData[i] = (rawData[i] / scaleFactor) * 1000; // 转换为uV}return convertedData;}/*** 移动平均滤波器 - 平滑高频噪声* @param data 原始ECG数据(uV)* @param windowSize 窗口大小(建议3-7)* @return 滤波后的数据*/public static double[] movingAverageFilter(double[] data, int windowSize) {if (windowSize < 1 || windowSize > data.length) {throw new IllegalArgumentException("Invalid window size");}double[] filtered = new double[data.length];int halfWindow = windowSize / 2;for (int i = 0; i < data.length; i++) {int start = Math.max(0, i - halfWindow);int end = Math.min(data.length - 1, i + halfWindow);double sum = 0;int count = 0;for (int j = start; j <= end; j++) {sum += data[j];count++;}filtered[i] = sum / count;}return filtered;}/*** 中值滤波器 - 有效去除脉冲噪声* @param data 原始ECG数据(uV)* @param windowSize 窗口大小(建议3-5)* @return 滤波后的数据*/public static double[] medianFilter(double[] data, int windowSize) {if (windowSize < 1 || windowSize > data.length || windowSize % 2 == 0) {throw new IllegalArgumentException("Window size must be odd and positive");}double[] filtered = new double[data.length];int halfWindow = windowSize / 2;double[] window = new double[windowSize];for (int i = 0; i < data.length; i++) {int start = Math.max(0, i - halfWindow);int end = Math.min(data.length - 1, i + halfWindow);// 填充窗口int index = 0;for (int j = start; j <= end; j++) {window[index++] = data[j];}// 对窗口数据进行排序Arrays.sort(window, 0, index);// 取中值filtered[i] = window[index / 2];}return filtered;}/*** 基于阈值的异常值过滤* @param data 原始ECG数据(uV)* @param thresholdMultiplier 阈值乘数(建议2.5-3.5)* @return 过滤后的数据*/public static double[] thresholdFilter(double[] data, double thresholdMultiplier) {// 计算数据的均值和标准差double mean = 0;for (double v : data) {mean += v;}mean /= data.length;double stdDev = 0;for (double v : data) {stdDev += Math.pow(v - mean, 2);}stdDev = Math.sqrt(stdDev / data.length);double threshold = thresholdMultiplier * stdDev;double[] filtered = new double[data.length];for (int i = 0; i < data.length; i++) {if (Math.abs(data[i] - mean) > threshold) {// 如果是异常值，用前后值的平均值替代double prev = i > 0 ? filtered[i-1] : mean;double next = i < data.length-1 ? data[i+1] : mean;filtered[i] = (prev + next) / 2;} else {filtered[i] = data[i];}}return filtered;}/*** 组合滤波器 - 先中值滤波再移动平均* @param data 原始ECG数据(uV)* @param medianWindow 中值滤波窗口大小(建议3)* @param averageWindow 移动平均窗口大小(建议5)* @return 滤波后的数据*/public static double[] combinedFilter(double[] data, int medianWindow, int averageWindow) {double[] medianFiltered = medianFilter(data, medianWindow);return movingAverageFilter(medianFiltered, averageWindow);}/*** 原始数据强过滤（处理ADC值）* @param rawData 原始ADC数据* @param maxAllowed 允许的最大ADC绝对值* @return 过滤后的原始ADC数据*/public static double[] filterRawData(double[] rawData, double maxAllowed) {if (rawData == null) {return new double[0];}double[] filtered = Arrays.copyOf(rawData, rawData.length);int windowSize = 7; // 使用前后各3个点（共7点窗口）for (int i = 0; i < filtered.length; i++) {if (Math.abs(filtered[i]) > maxAllowed) {// 获取周围正常值的滑动窗口中值filtered[i] = getSlidingWindowReplacement(filtered, i, windowSize, maxAllowed);}}return filtered;}private static double getSlidingWindowReplacement(double[] data, int centerIdx,int windowSize, double maxAllowed) {int halfWindow = windowSize / 2;List<Double> validValues = new ArrayList<>();// 收集窗口内有效值for (int i = -halfWindow; i <= halfWindow; i++) {int actualIdx = centerIdx + i;if (actualIdx >= 0 && actualIdx < data.length &&Math.abs(data[actualIdx]) <= maxAllowed) {validValues.add(data[actualIdx]);}}// 处理策略（按优先级）：if (!validValues.isEmpty()) {// 1. 有有效值则取中位数Collections.sort(validValues);return validValues.get(validValues.size() / 2);} else {// 2. 无有效值则取前一个正常值（向前搜索）for (int i = centerIdx - 1; i >= 0; i--) {if (Math.abs(data[i]) <= maxAllowed) {return data[i];}}// 3. 极端情况返回0return 0.0;}}}

图片生成 方法

package com.shinrun.infrastructure.util;import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartUtils;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.axis.NumberAxis;
import org.jfree.chart.plot.XYPlot;
import org.jfree.chart.renderer.xy.XYLineAndShapeRenderer;
import org.jfree.chart.ui.RectangleInsets;
import org.jfree.data.xy.XYSeries;
import org.jfree.data.xy.XYSeriesCollection;import java.awt.*;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.Base64;/*** 医疗级心电图生成工具类（10段垂直排列）* 实现了标准心电图纸网格和比例尺*/
public class ECGChartGenerator {// ============= 默认参数配置 =============private static final int DEFAULT_SAMPLE_RATE = 500; // 默认采样率500Hzprivate static final int SEGMENT_COUNT = 10; // 固定10段心电图private static final int DEFAULT_WIDTH = 800; // 图片默认宽度private static final int SEGMENT_HEIGHT = 150; // 每段心电图高度private static final int TOTAL_HEIGHT = SEGMENT_COUNT * SEGMENT_HEIGHT; // 总高度// 心电图纸网格参数（医疗标准）private static final int SMALL_GRID_MM = 1; // 小方格1mmprivate static final int LARGE_GRID_MM = 5; // 大方格5mm(5个小方格)private static final int GRID_SIZE_PX = 12; // 1mm对应的像素数(方法二)// 心电图显示参数private static final double DEFAULT_MM_PER_MV = 10.0; // 标准灵敏度:10mm/mVprivate static final double DEFAULT_PAPER_SPEED_MM_PER_SEC = 25.0; // 标准走纸速度:25mm/sprivate static final int DEFAULT_HEIGHT = 600; // 图片默认高度/*** 生成无标签的心电图纸网格*/public static String generateECGGrid() throws IOException {// 创建空数据集（不需要实际数据）XYSeriesCollection dataset = new XYSeriesCollection();// 创建图表JFreeChart chart = ChartFactory.createXYLineChart(null, "", "", dataset);// 自定义网格样式customizeGridChart(chart);return convertChartToBase64(chart, DEFAULT_WIDTH, DEFAULT_HEIGHT);}/*** 自定义网格图表样式*/private static void customizeGridChart(JFreeChart chart) {XYPlot plot = chart.getXYPlot();// 1. 背景设置plot.setBackgroundPaint(Color.WHITE);chart.setBackgroundPaint(Color.WHITE);// 2. 网格线设置(医疗标准)plot.setDomainGridlinePaint(new Color(255, 200, 200)); // 小网格线颜色plot.setRangeGridlinePaint(new Color(255, 200, 200));plot.setDomainGridlineStroke(new BasicStroke(0.5f));   // 小网格线宽度plot.setRangeGridlineStroke(new BasicStroke(0.5f));// 计算网格大小(像素)double smallGridPx = SMALL_GRID_MM * GRID_SIZE_PX;double largeGridPx = LARGE_GRID_MM * GRID_SIZE_PX;// 3. X轴(时间轴)设置 - 隐藏所有标签和刻度NumberAxis xAxis = (NumberAxis) plot.getDomainAxis();xAxis.setAxisLineVisible(false);xAxis.setTickMarksVisible(false);xAxis.setTickLabelsVisible(false);xAxis.setStandardTickUnits(NumberAxis.createIntegerTickUnits());xAxis.setTickUnit(new org.jfree.chart.axis.NumberTickUnit(largeGridPx));// 4. Y轴(幅度轴)设置 - 隐藏所有标签和刻度NumberAxis yAxis = (NumberAxis) plot.getRangeAxis();yAxis.setAxisLineVisible(false);yAxis.setTickMarksVisible(false);yAxis.setTickLabelsVisible(false);yAxis.setTickUnit(new org.jfree.chart.axis.NumberTickUnit(largeGridPx));// 5. 移除所有渲染器（因为我们只需要网格）plot.setRenderer(null);// 6. 调整图表边距plot.setAxisOffset(new RectangleInsets(5, 5, 5, 5));// 7. 确保没有图例chart.removeLegend();// 8. 设置合适的范围以显示网格xAxis.setRange(0, DEFAULT_WIDTH / GRID_SIZE_PX);yAxis.setRange(0, DEFAULT_HEIGHT / GRID_SIZE_PX);}/*** 使用默认参数生成10段ECG Base64图片*/public static String generateSegmentedECGImage(double[] ecgData) throws IOException {return generateSegmentedECGImage(ecgData, DEFAULT_SAMPLE_RATE, DEFAULT_MM_PER_MV, DEFAULT_PAPER_SPEED_MM_PER_SEC);}/*** 自定义参数生成10段ECG Base64图片*/public static String generateSegmentedECGImage(double[] ecgData, int sampleRate, double mmPerMv, double paperSpeedMmPerSec) throws IOException {// 计算每段数据点数int pointsPerSegment = ecgData.length / SEGMENT_COUNT;XYSeriesCollection dataset = new XYSeriesCollection();// 创建10个数据段for (int seg = 0; seg < SEGMENT_COUNT; seg++) {int start = seg * pointsPerSegment;int end = (seg == SEGMENT_COUNT - 1) ? ecgData.length : start + pointsPerSegment;XYSeries series = new XYSeries("ECG Segment " + (seg + 1));// 垂直偏移量(使各段分开显示)double yOffset = -seg * 2.0; // 每段下移2mVfor (int i = start; i < end; i++) {// 计算时间并转换为毫米(基于走纸速度)double timeSec = (i - start) / (double) sampleRate;double xPosMm = timeSec * paperSpeedMmPerSec;// 转换为像素double xPixel = xPosMm * GRID_SIZE_PX;// 转换ECG值到mV(输入是uV)double valueMv = ecgData[i] / 1000.0;// 应用垂直比例尺(mm/mV)double yPosMm = valueMv * mmPerMv;// 转换为像素并加上偏移量double yPixel = yPosMm * GRID_SIZE_PX + (yOffset * mmPerMv * GRID_SIZE_PX);series.add(xPixel, yPixel);}dataset.addSeries(series);}// 创建图表JFreeChart chart = ChartFactory.createXYLineChart(null, "时间 (mm)", "幅度 (mm)", dataset);// 自定义心电图样式customizeMedicalECGChart(chart, mmPerMv, paperSpeedMmPerSec);return convertChartToBase64(chart, DEFAULT_WIDTH, TOTAL_HEIGHT);}/*** 自定义心电图图表样式(医疗标准)*/private static void customizeMedicalECGChart(JFreeChart chart, double mmPerMv, double paperSpeedMmPerSec) {XYPlot plot = chart.getXYPlot();// 1. 背景设置plot.setBackgroundPaint(Color.WHITE);chart.setBackgroundPaint(Color.WHITE);// 2. 网格线设置(医疗标准)plot.setDomainGridlinePaint(new Color(255, 200, 200)); // 小网格线颜色plot.setRangeGridlinePaint(new Color(255, 200, 200));plot.setDomainGridlineStroke(new BasicStroke(0.5f));   // 小网格线宽度plot.setRangeGridlineStroke(new BasicStroke(0.5f));// 计算网格大小(像素)double smallGridPx = SMALL_GRID_MM * GRID_SIZE_PX;double largeGridPx = LARGE_GRID_MM * GRID_SIZE_PX;// 3. X轴(时间轴)设置NumberAxis xAxis = (NumberAxis) plot.getDomainAxis();xAxis.setAxisLinePaint(Color.BLACK);xAxis.setTickMarkPaint(Color.BLACK);xAxis.setStandardTickUnits(NumberAxis.createIntegerTickUnits());xAxis.setTickUnit(new org.jfree.chart.axis.NumberTickUnit(largeGridPx));// 新版JFreeChart不再支持setMinorTickMarkPaint，改用以下方式设置次刻度xAxis.setMinorTickCount(4);xAxis.setMinorTickMarksVisible(true);// 4. Y轴(幅度轴)设置NumberAxis yAxis = (NumberAxis) plot.getRangeAxis();yAxis.setAxisLinePaint(Color.BLACK);yAxis.setTickMarkPaint(Color.BLACK);yAxis.setTickUnit(new org.jfree.chart.axis.NumberTickUnit(largeGridPx));yAxis.setMinorTickCount(4);yAxis.setMinorTickMarksVisible(true);// 5. 心电图曲线渲染设置XYLineAndShapeRenderer renderer = new XYLineAndShapeRenderer();renderer.setSeriesPaint(0, Color.BLACK);renderer.setSeriesStroke(0, new BasicStroke(1.5f));// 为所有段应用相同的渲染器for (int i = 0; i < SEGMENT_COUNT; i++) {plot.setRenderer(i, renderer);renderer.setSeriesPaint(i, Color.BLACK);renderer.setSeriesStroke(i, new BasicStroke(1.5f));renderer.setSeriesShapesVisible(i, false);}// 6. 调整图表边距plot.setAxisOffset(new RectangleInsets(5, 5, 5, 5));// 7. 移除图例chart.removeLegend();// 8. 添加标题显示参数chart.setTitle("心电图 - " + mmPerMv + "mm/mV, 走纸速度 " + paperSpeedMmPerSec + "mm/s");}/*** 使用默认参数生成10段ECG Base64图片（无刻度值）*/public static String generateSegmentedECGImageNoLabels(double[] ecgData) throws IOException {return generateSegmentedECGImageNoLabels(ecgData, DEFAULT_SAMPLE_RATE,DEFAULT_MM_PER_MV, DEFAULT_PAPER_SPEED_MM_PER_SEC);}/*** 自定义参数生成10段ECG Base64图片（无刻度值）*/public static String generateSegmentedECGImageNoLabels(double[] ecgData, int sampleRate,double mmPerMv, double paperSpeedMmPerSec) throws IOException {// 计算每段数据点数int pointsPerSegment = ecgData.length / SEGMENT_COUNT;XYSeriesCollection dataset = new XYSeriesCollection();// 创建10个数据段for (int seg = 0; seg < SEGMENT_COUNT; seg++) {int start = seg * pointsPerSegment;int end = (seg == SEGMENT_COUNT - 1) ? ecgData.length : start + pointsPerSegment;XYSeries series = new XYSeries("ECG Segment " + (seg + 1));// 垂直偏移量(使各段分开显示)double yOffset = -seg * 2.0; // 每段下移2mVfor (int i = start; i < end; i++) {// 计算时间并转换为毫米(基于走纸速度)double timeSec = (i - start) / (double) sampleRate;double xPosMm = timeSec * paperSpeedMmPerSec;// 转换为像素double xPixel = xPosMm * GRID_SIZE_PX;// 转换ECG值到mV(输入是uV)double valueMv = ecgData[i] / 1000.0;// 应用垂直比例尺(mm/mV)double yPosMm = valueMv * mmPerMv;// 转换为像素并加上偏移量double yPixel = yPosMm * GRID_SIZE_PX + (yOffset * mmPerMv * GRID_SIZE_PX);series.add(xPixel, yPixel);}dataset.addSeries(series);}// 创建图表JFreeChart chart = ChartFactory.createXYLineChart(null, "", "", dataset); // 空标题和空轴标签// 自定义心电图样式（无刻度值）customizeMedicalECGChartNoLabels(chart, mmPerMv, paperSpeedMmPerSec);return convertChartToBase64(chart, DEFAULT_WIDTH, TOTAL_HEIGHT);}/*** 自定义心电图图表样式(医疗标准，无刻度值)*/private static void customizeMedicalECGChartNoLabels(JFreeChart chart, double mmPerMv, double paperSpeedMmPerSec) {XYPlot plot = chart.getXYPlot();// 1. 背景设置plot.setBackgroundPaint(Color.WHITE);chart.setBackgroundPaint(Color.WHITE);// 2. 网格线设置(医疗标准)plot.setDomainGridlinePaint(new Color(255, 200, 200)); // 小网格线颜色plot.setRangeGridlinePaint(new Color(255, 200, 200));plot.setDomainGridlineStroke(new BasicStroke(0.5f));   // 小网格线宽度plot.setRangeGridlineStroke(new BasicStroke(0.5f));// 计算网格大小(像素)double smallGridPx = SMALL_GRID_MM * GRID_SIZE_PX;double largeGridPx = LARGE_GRID_MM * GRID_SIZE_PX;// 3. X轴(时间轴)设置 - 隐藏刻度值NumberAxis xAxis = (NumberAxis) plot.getDomainAxis();xAxis.setAxisLineVisible(false);          // 隐藏轴线xAxis.setTickMarksVisible(false);         // 隐藏刻度线xAxis.setTickLabelsVisible(false);        // 隐藏刻度标签xAxis.setStandardTickUnits(NumberAxis.createIntegerTickUnits());xAxis.setTickUnit(new org.jfree.chart.axis.NumberTickUnit(largeGridPx));// 4. Y轴(幅度轴)设置 - 隐藏刻度值NumberAxis yAxis = (NumberAxis) plot.getRangeAxis();yAxis.setAxisLineVisible(false);          // 隐藏轴线yAxis.setTickMarksVisible(false);         // 隐藏刻度线yAxis.setTickLabelsVisible(false);        // 隐藏刻度标签yAxis.setTickUnit(new org.jfree.chart.axis.NumberTickUnit(largeGridPx));// 5. 心电图曲线渲染设置XYLineAndShapeRenderer renderer = new XYLineAndShapeRenderer();renderer.setSeriesPaint(0, Color.BLACK);renderer.setSeriesStroke(0, new BasicStroke(0.8f));// 为所有段应用相同的渲染器for (int i = 0; i < SEGMENT_COUNT; i++) {plot.setRenderer(i, renderer);renderer.setSeriesPaint(i, Color.BLACK);renderer.setSeriesStroke(i, new BasicStroke(0.8f));renderer.setSeriesShapesVisible(i, false);}// 6. 调整图表边距plot.setAxisOffset(new RectangleInsets(5, 5, 5, 5));// 7. 移除图例chart.removeLegend();// 8. 移除标题chart.setTitle("心电图 - " + mmPerMv + "mm/mV, 走纸速度 " + paperSpeedMmPerSec + "mm/s");}/*** 将图表转换为Base64编码的PNG图片*/private static String convertChartToBase64(JFreeChart chart, int width, int height) throws IOException {try (ByteArrayOutputStream outputStream = new ByteArrayOutputStream()) {ChartUtils.writeChartAsPNG(outputStream, chart, width, height);return "data:image/png;base64," + Base64.getEncoder().encodeToString(outputStream.toByteArray());}}
}

讲解使用

我的心电图数据是来着于第三方平台的（是由机器将心电数据文件上传到第三方系统，第三方系统给我返回的double数组）

首先是进行 滤波，数据会有很大的外界因素影响，波动会很大，
再将数据转换成mv
再画图，进行调试

  public String generateEcg(double[] rawData ) {// 转换参数double scaleFactor = 20.0;String oss="";// 方法1: 使用默认参数处理double[] processedECG = ECGDataConverter.filterRawData(rawData,4000);//转换成mvdouble[] doubles = ECGDataConverter.convertToMillivolts(processedECG, scaleFactor);// 生成时间轴try {String string = ECGChartGenerator.generateSegmentedECGImageNoLabels(doubles);oss= uploadFile(string, "image/ecg");} catch (IOException e) {throw new RuntimeException(e);}return oss;}

关键点

double[] processedECG = ECGDataConverter.filterRawData(rawData,4000);

这里 滤波参数我给的4000 其实就是 将超过4000的值给过滤掉，第三方给的数据 人的平均心跳峰值不超过4000，超过4000的那就不对需要过滤掉，这个根据你实际的数据进行修改

    double scaleFactor = 20.0;//转换成mvdouble[] doubles = ECGDataConverter.convertToMillivolts(processedECG, scaleFactor);

这里传个参数scaleFactor ，其实就是对数据进行除一下，这里由于第三方给的数据不太规范，不除以一下的话画出来不太好看
一般数据除到是百位数就行了

如果上面两点没有做好的话效果可能如下