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问尝试在opencv.js中使用goodFeaturesToTrack
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Stack Overflow用户

提问于 2021-01-24 23:53:36

回答 1查看 93关注 0票数 0

我正在阅读Tutorial，并试图将示例重新编码为javascript，以尝试goodFeaturesToTrack()，但收效甚微，我就是找不到任何有文档记录的javascript示例进行比较。

我正在尝试找出最终需要什么来检测一张纸上的照片上的4个角，甚至不知道goodFeaturesToTrack是否是正确的方向，但是我无法在javascript中使用这个基本的样本。

python示例如下所示：

    import numpy as np
    import cv2 as cv
    from matplotlib import pyplot as plt
    img = cv.imread('blox.jpg')
    gray = cv.cvtColor(img,cv.COLOR_BGR2GRAY)
    corners = cv.goodFeaturesToTrack(gray,25,0.01,10)
    corners = np.int0(corners)
    for i in corners:
       x,y = i.ravel()
       cv.circle(img,(x,y),3,255,-1)
    plt.imshow(img),plt.show()

要将此代码转换为javascript运行示例，我有以下代码：

    <html>
    <head>
    <script src='https://docs.opencv.org/3.4.0/opencv.js'></script>
    </head>
    <body>
       <canvas id="canvas" style='border:solid 1px red'></canvas>

       <script>
       const canvas = document.querySelector('#canvas');
       var context = canvas.getContext('2d');
       var img = new Image();
       img.src = 'images/shitomasi_block1.jpg'; // taken from https://docs.opencv.org/4.0.0- 
       beta/shitomasi_block1.jpg

       img.onload = function() {
          canvas.width = 200;
          canvas.height = 200;
          var hRatio = canvas.width / img.width;
          var vRatio = canvas.height / img.height;
          var ratio = Math.min(hRatio, vRatio);
          context.drawImage(img, 0, 0, img.width, img.height,
            0, 0, img.width * ratio, img.height * ratio);

          console.log('grayscaling the image...');
          var src = cv.imread(canvas.id);
          let dst = new cv.Mat();
          var grayscale = cv.cvtColor(src, dst, cv.COLOR_RGB2GRAY, );
          cv.imshow(canvas.id, dst);

          console.log('doing good features....');
          var green = new cv.Scalar(0, 255, 0);
          console.log('24');
          // xx the code then fails on the next line....
          var corners = cv.goodFeaturesToTrack(grayscale, 25, 0.01, 10)

          // the following lines are not tested and are likely to need some work...
          console.log('28');
          console.log(corners);
          ?? for (var i = 0; i < corners.length; i++) {
             ?? var x, y = i.ravel();
             ?? cv.circle(img, (x, y), 3, green, -1);
          ??}
          ??plt.imshow(img), plt.show();
    }

    </script>
    </body>
    </html>

我得到的错误是：

    Uncaught BindingError {name: "BindingError", message: "Function 'goodFeaturesToTrack' called with an inva… arg5Wired, arg6Wired, arg7Wired, arg8Wired);↵})!", stack: "BindingError: Function 'goodFeaturesToTrack' calle…p://localhost/test/public_html/test2.html:37:22)"} 
    message: "Function 'goodFeaturesToTrack' called with an invalid number of arguments (4) - expects one of (,,,,,function goodFeaturesToTrack(arg0, arg1, arg2, arg3, arg4) {↵if (arguments.length !== 5) {↵throwBindingError('function goodFeaturesToTrack called with ' + arguments.length + ' arguments, expected 5 args!');↵}↵var arg0Wired = argType0.toWireType(null, arg0); // Mat↵var arg1Wired = argType1.toWireType(null, arg1); // Mat↵var arg2Wired = argType2.toWireType(null, arg2); // int↵var arg3Wired = argType3.toWireType(null, arg3); // double↵var arg4Wired = argType4.toWireType(null, arg4); // double↵invoker(fn, arg0Wired, arg1Wired, arg2Wired, arg3Wired, arg4Wired);↵},function goodFeaturesToTrack(arg0, arg1, arg2, arg3, arg4, arg5) {↵if (arguments.length !== 6) {↵throwBindingError('function goodFeaturesToTrack called with ' + arguments.length + ' arguments, expected 6 args!');↵}↵var arg0Wired = argType0.toWireType(null, arg0); // Mat↵var arg1Wired = argType1.toWireType(null, arg1); // Mat↵var arg2Wired = argType2.toWireType(null, arg2); // int↵var arg3Wired = argType3.toWireType(null, arg3); // double↵var arg4Wired = argType4.toWireType(null, arg4); // double↵var arg5Wired = argType5.toWireType(null, arg5); // Mat↵invoker(fn, arg0Wired, arg1Wired, arg2Wired, arg3Wired, arg4Wired, arg5Wired);↵},function goodFeaturesToTrack(arg0, arg1, arg2, arg3, arg4, arg5, arg6) {↵if (arguments.length !== 7) {↵throwBindingError('function goodFeaturesToTrack called with ' + arguments.length + ' arguments, expected 7 args!');↵}↵var arg0Wired = argType0.toWireType(null, arg0); // Mat↵var arg1Wired = argType1.toWireType(null, arg1); // Mat↵var arg2Wired = argType2.toWireType(null, arg2); // int↵var arg3Wired = argType3.toWireType(null, arg3); // double↵var arg4Wired = argType4.toWireType(null, arg4); // double↵var arg5Wired = argType5.toWireType(null, arg5); // Mat↵var arg6Wired = argType6.toWireType(null, arg6); // int↵invoker(fn, arg0Wired, arg1Wired, arg2Wired, arg3Wired, arg4Wired, arg5Wired, arg6Wired);↵},function goodFeaturesToTrack(arg0, arg1, arg2, arg3, arg4, arg5, arg6, arg7) {↵if (arguments.length !== 8) {↵throwBindingError('function goodFeaturesToTrack called with ' + arguments.length + ' arguments, expected 8 args!');↵}↵var arg0Wired = argType0.toWireType(null, arg0); // Mat↵var arg1Wired = argType1.toWireType(null, arg1); // Mat↵var arg2Wired = argType2.toWireType(null, arg2); // int↵var arg3Wired = argType3.toWireType(null, arg3); // double↵var arg4Wired = argType4.toWireType(null, arg4); // double↵var arg5Wired = argType5.toWireType(null, arg5); // Mat↵var arg6Wired = argType6.toWireType(null, arg6); // int↵var arg7Wired = argType7.toWireType(null, arg7); // bool↵invoker(fn, arg0Wired, arg1Wired, arg2Wired, arg3Wired, arg4Wired, arg5Wired, arg6Wired, arg7Wired);↵},function goodFeaturesToTrack(arg0, arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8) {↵if (arguments.length !== 9) {↵throwBindingError('function goodFeaturesToTrack called with ' + arguments.length + ' arguments, expected 9 args!');↵}↵var arg0Wired = argType0.toWireType(null, arg0); // Mat↵var arg1Wired = argType1.toWireType(null, arg1); // Mat↵var arg2Wired = argType2.toWireType(null, arg2); // int↵var arg3Wired = argType3.toWireType(null, arg3); // double↵var arg4Wired = argType4.toWireType(null, arg4); // double↵var arg5Wired = argType5.toWireType(null, arg5); // Mat↵var arg6Wired = argType6.toWireType(null, arg6); // int↵var arg7Wired = argType7.toWireType(null, arg7); // bool↵var arg8Wired = argType8.toWireType(null, arg8); // double↵invoker(fn, arg0Wired, arg1Wired, arg2Wired, arg3Wired, arg4Wired, arg5Wired, arg6Wired, arg7Wired, arg8Wired);↵})!"
    name: "BindingError" 
/*
* 提示：该行代码过长，系统自动注释不进行高亮。一键复制会移除系统注释 
* stack: "BindingError: Function 'goodFeaturesToTrack' called with an invalid number of arguments (4) - expects one of (,,,,,function goodFeaturesToTrack(arg0, arg1, arg2, arg3, arg4) {↵if (arguments.length !== 5) {↵throwBindingError('function goodFeaturesToTrack called with ' + arguments.length + ' arguments, expected 5 args!');↵}↵var arg0Wired = argType0.toWireType(null, arg0); // Mat↵var arg1Wired = argType1.toWireType(null, arg1); // Mat↵var arg2Wired = argType2.toWireType(null, arg2); // int↵var arg3Wired = argType3.toWireType(null, arg3); // double↵var arg4Wired = argType4.toWireType(null, arg4); // double↵invoker(fn, arg0Wired, arg1Wired, arg2Wired, arg3Wired, arg4Wired);↵},function goodFeaturesToTrack(arg0, arg1, arg2, arg3, arg4, arg5) {↵if (arguments.length !== 6) {↵throwBindingError('function goodFeaturesToTrack called with ' + arguments.length + ' arguments, expected 6 args!');↵}↵var arg0Wired = argType0.toWireType(null, arg0); // Mat↵var arg1Wired = argType1.toWireType(null, arg1); // Mat↵var arg2Wired = argType2.toWireType(null, arg2); // int↵var arg3Wired = argType3.toWireType(null, arg3); // double↵var arg4Wired = argType4.toWireType(null, arg4); // double↵var arg5Wired = argType5.toWireType(null, arg5); // Mat↵invoker(fn, arg0Wired, arg1Wired, arg2Wired, arg3Wired, arg4Wired, arg5Wired);↵},function goodFeaturesToTrack(arg0, arg1, arg2, arg3, arg4, arg5, arg6) {↵if (arguments.length !== 7) {↵throwBindingError('function goodFeaturesToTrack called with ' + arguments.length + ' arguments, expected 7 args!');↵}↵var arg0Wired = argType0.toWireType(null, arg0); // Mat↵var arg1Wired = argType1.toWireType(null, arg1); // Mat↵var arg2Wired = argType2.toWireType(null, arg2); // int↵var arg3Wired = argType3.toWireType(null, arg3); // double↵var arg4Wired = argType4.toWireType(null, arg4); // double↵var arg5Wired = argType5.toWireType(null, arg5); // Mat↵var arg6Wired = argType6.toWireType(null, arg6); // int↵invoker(fn, arg0Wired, arg1Wired, arg2Wired, arg3Wired, arg4Wired, arg5Wired, arg6Wired);↵},function goodFeaturesToTrack(arg0, arg1, arg2, arg3, arg4, arg5, arg6, arg7) {↵if (arguments.length !== 8) {↵throwBindingError('function goodFeaturesToTrack called with ' + arguments.length + ' arguments, expected 8 args!');↵}↵var arg0Wired = argType0.toWireType(null, arg0); // Mat↵var arg1Wired = argType1.toWireType(null, arg1); // Mat↵var arg2Wired = argType2.toWireType(null, arg2); // int↵var arg3Wired = argType3.toWireType(null, arg3); // double↵var arg4Wired = argType4.toWireType(null, arg4); // double↵var arg5Wired = argType5.toWireType(null, arg5); // Mat↵var arg6Wired = argType6.toWireType(null, arg6); // int↵var arg7Wired = argType7.toWireType(null, arg7); // bool↵invoker(fn, arg0Wired, arg1Wired, arg2Wired, arg3Wired, arg4Wired, arg5Wired, arg6Wired, arg7Wired);↵},function goodFeaturesToTrack(arg0, arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8) {↵if (arguments.length !== 9) {↵throwBindingError('function goodFeaturesToTrack called with ' + arguments.length + ' arguments, expected 9 args!');↵}↵var arg0Wired = argType0.toWireType(null, arg0); // Mat↵var arg1Wired = argType1.toWireType(null, arg1); // Mat↵var arg2Wired = argType2.toWireType(null, arg2); // int↵var arg3Wired = argType3.toWireType(null, arg3); // double↵var arg4Wired = argType4.toWireType(null, arg4); // double↵var arg5Wired = argType5.toWireType(null, arg5); // Mat↵var arg6Wired = argType6.toWireType(null, arg6); // int↵var arg7Wired = argType7.toWireType(null, arg7); // bool↵var arg8Wired = argType8.toWireType(null, arg8); // double↵invoker(fn, arg0Wired, arg1Wired, arg2Wired, arg3Wired, arg4Wired, arg5Wired, arg6Wired, arg7Wired, arg8Wired);↵})!↵if (arguments.length !== 5) {↵throwBindingError('function goodFeaturesToTrack called with ' + arguments.length + ' arguments, expected 5 args!');↵}↵var arg0Wired = argType0.toWireType(null, arg0); // Mat↵var arg1Wired = argType1.toWireType(null, arg1); // Mat↵var arg2Wired = argType2.toWireType(null, arg2); // int↵var arg3Wired = argType3.toWireType(null, arg3); // double↵var arg4Wired = argType4.toWireType(null, arg4); // double↵invoker(fn, arg0Wired, arg1Wired, arg2Wired, arg3Wired, arg4Wired);↵},function goodFeaturesToTrack(arg0, arg1, arg2, arg3, arg4, arg5) {↵if (arguments.length !== 6) {↵throwBindingError('function goodFeaturesToTrack called with ' + arguments.length + ' arguments, expected 6 args!');↵}↵var arg0Wired = argType0.toWireType(null, arg0); // Mat↵var arg1Wired = argType1.toWireType(null, arg1); // Mat↵var arg2Wired = argType2.toWireType(null, arg2); // int↵var arg3Wired = argType3.toWireType(null, arg3); // double↵var arg4Wired = argType4.toWireType(null, arg4); // double↵var arg5Wired = argType5.toWireType(null, arg5); // Mat↵invoker(fn, arg0Wired, arg1Wired, arg2Wired, arg3Wired, arg4Wired, arg5Wired);↵},function goodFeaturesToTrack(arg0, arg1, arg2, arg3, arg4, arg5, arg6) {↵if (arguments.length !== 7) {↵throwBindingError('function goodFeaturesToTrack called with ' + arguments.length + ' arguments, expected 7 args!');↵}↵var arg0Wired = argType0.toWireType(null, arg0); // Mat↵var arg1Wired = argType1.toWireType(null, arg1); // Mat↵var arg2Wired = argType2.toWireType(null, arg2); // int↵var arg3Wired = argType3.toWireType(null, arg3); // double↵var arg4Wired = argType4.toWireType(null, arg4); // double↵var arg5Wired = argType5.toWireType(null, arg5); // Mat↵var arg6Wired = argType6.toWireType(null, arg6); // int↵invoker(fn, arg0Wired, arg1Wired, arg2Wired, arg3Wired, arg4Wired, arg5Wired, arg6Wired);↵},function goodFeaturesToTrack(arg0, arg1, arg2, arg3, arg4, arg5, arg6, arg7) {↵if (arguments.length !== 8) {↵throwBindingError('function goodFeaturesToTrack called with ' + arguments.length + ' arguments, expected 8 args!');↵}↵var arg0Wired = argType0.toWireType(null, arg0); // Mat↵var arg1Wired = argType1.toWireType(null, arg1); // Mat↵var arg2Wired = argType2.toWireType(null, arg2); // int↵var arg3Wired = argType3.toWireType(null, arg3); // double↵var arg4Wired = argType4.toWireType(null, arg4); // double↵var arg5Wired = argType5.toWireType(null, arg5); // Mat↵var arg6Wired = argType6.toWireType(null, arg6); // int↵var arg7Wired = argType7.toWireType(null, arg7); // bool↵invoker(fn, arg0Wired, arg1Wired, arg2Wired, arg3Wired, arg4Wired, arg5Wired, arg6Wired, arg7Wired);↵},function goodFeaturesToTrack(arg0, arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8) {↵if (arguments.length !== 9) {↵throwBindingError('function goodFeaturesToTrack called with ' + arguments.length + ' arguments, expected 9 args!');↵}↵var arg0Wired = argType0.toWireType(null, arg0); // Mat↵var arg1Wired = argType1.toWireType(null, arg1); // Mat↵var arg2Wired = argType2.toWireType(null, arg2); // int↵var arg3Wired = argType3.toWireType(null, arg3); // double↵var arg4Wired = argType4.toWireType(null, arg4); // double↵var arg5Wired = argType5.toWireType(null, arg5); // Mat↵var arg6Wired = argType6.toWireType(null, arg6); // int↵var arg7Wired = argType7.toWireType(null, arg7); // bool↵var arg8Wired = argType8.toWireType(null, arg8); // double↵invoker(fn, arg0Wired, arg1Wired, arg2Wired, arg3Wired, arg4Wired, arg5Wired, arg6Wired, arg7Wired, arg8Wired);↵})!↵    at BindingError.<anonymous> (http://localhost/test/public_html/javascript/opencv.3.4.js:30:6819009)↵    at new BindingError (eval at createNamedFunction (http://localhost/test/public_html/javascript/opencv.3.4.js:30:6818718), <anonymous>:4:34)↵    at throwBindingError (http://localhost/test/public_html/javascript/opencv.3.4.js:30:6824136)↵    at Object.proto.<computed> [as goodFeaturesToTrack] (http://localhost/test/public_html/javascript/opencv.3.4.js:30:6829116)↵    at Image.img.onload (http://localhost/test/public_html/test2.html:37:22)"
*/
    __proto__: Error

我想要问的第一个问题是，这是否是正确的方向，然后如果有人看到goodFeaturesToTrack在javascript中实际工作-使用示例代码片段来显示我的错误所在。

有人能帮上忙吗？

javascript

opencv

computer-vision

回答 1

Stack Overflow用户

发布于 2021-07-09 17:20:52

正确的方法是

let corners = new cv.Mat();
cv.goodFeaturesToTrack(grayscale, corners, 4, 0.5, 50);

它给了你一堆“角”，但我不知道如何利用它^^

票数 0

页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持

原文链接：

https://stackoverflow.com/questions/65872699

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