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javascript - cv.Mat 不是构造函数 opencv

问题描述

我收到这个错误 TypeError: cv.Mat is not a constructor

我尝试做几乎所有事情都无法在互联网上找到任何解决方案

索引.html

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Hello OpenCV.js</title>
</head>
<body>
<h2>Hello OpenCV.js</h2>
<p id="status">OpenCV.js is loading...</p>
<div>
<img src="dd.jpg" style="display:none;" id ="img">
<canvas id = "videoInput" height="500" width="500"></canvas>
<canvas id = "canvasOutput" height="500" width="500"></canvas>

<script async type="text/javascript" src="index.js"></script>
<script async src="opencv.js" onload="onOpenCvReady();" type="text/javascript"></script>
</body>
</html>

index.js

  document.getElementById('status').innerHTML = 'OpenCV.js is ready.';
  let video = document.getElementById('videoInput');
  let src = new cv.Mat(video.height, video.width, cv.CV_8UC4);
  let dst = new cv.Mat(video.height, video.width, cv.CV_8UC4);
  let gray = new cv.Mat();
  let cap = new cv.VideoCapture(video);
  let faces = new cv.RectVector();
  let classifier = new cv.CascadeClassifier();

  // load pre-trained classifiers
  classifier.load('haarcascade_frontalface_default.xml');

  const FPS = 30;
  function processVideo() {
      try {
          if (!streaming) {
              // clean and stop.
              src.delete();
              dst.delete();
              gray.delete();
              faces.delete();
              classifier.delete();
              return;
          }
          let begin = Date.now();
          // start processing.
          cap.read(src);
          src.copyTo(dst);
          cv.cvtColor(dst, gray, cv.COLOR_RGBA2GRAY, 0);
          // detect faces.
          classifier.detectMultiScale(gray, faces, 1.1, 3, 0);
          // draw faces.
          for (let i = 0; i < faces.size(); ++i) {
              let face = faces.get(i);
              let point1 = new cv.Point(face.x, face.y);
              let point2 = new cv.Point(face.x + face.width, face.y + face.height);
              cv.rectangle(dst, point1, point2, [255, 0, 0, 255]);
          }
          cv.imshow('canvasOutput', dst);
          // schedule the next one.
          let delay = 1000/FPS - (Date.now() - begin);
          setTimeout(processVideo, delay);
      } catch (err) {
          utils.printError(err);
      }
  };

  // schedule the first one.
  setTimeout(processVideo, 0);
}

我还导入了 opencv.js，因为我有它的下载版本。猜猜有一些初始化问题，请帮我解决它...

标签： javascriptopencv

解决方案

opencv.js 在真正初始化之前加载并触发 onload 事件。为了等到 opencv.js 真正准备好，opencv.js 提供了一个挂钩“onRuntimeInitialized”。像这样使用它：

function openCvReady() {
  cv['onRuntimeInitialized']=()=>{
    // do all your work here
  };
}

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