1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Image Foreground Example</title>
<link href="js_example_style.css" rel="stylesheet" type="text/css" />
</head>
<body>
<h2>Image Foreground Example</h2>
<p>
<canvas> elements named <b>canvasInput</b> and <b>canvasOutput</b> have been prepared.<br>
Click <b>Try it</b> button to see the result. You can choose another image.<br>
You can change the code in the <textarea> to investigate more.
</p>
<div>
<div class="control"><button id="tryIt" disabled>Try it</button></div>
<textarea class="code" rows="9" cols="100" id="codeEditor" spellcheck="false">
</textarea>
<p class="err" id="errorMessage"></p>
</div>
<div>
<table cellpadding="0" cellspacing="0" width="0" border="0">
<tr>
<td>
<canvas id="canvasInput"></canvas>
</td>
<td>
<canvas id="canvasOutput"></canvas>
</td>
</tr>
<tr>
<td>
<div class="caption">canvasInput <input type="file" id="fileInput" name="file" accept="image/*" /></div>
</td>
<td>
<div class="caption">canvasOutput</div>
</td>
</tr>
</table>
</div>
<script src="utils.js" type="text/javascript"></script>
<script id="codeSnippet" type="text/code-snippet">
let src = cv.imread('canvasInput');
let dst = new cv.Mat();
let gray = new cv.Mat();
let opening = new cv.Mat();
let coinsBg = new cv.Mat();
let coinsFg = new cv.Mat();
let distTrans = new cv.Mat();
cv.cvtColor(src, gray, cv.COLOR_RGBA2GRAY, 0);
cv.threshold(gray, gray, 0, 255, cv.THRESH_BINARY_INV + cv.THRESH_OTSU);
let M = cv.Mat.ones(3, 3, cv.CV_8U);
cv.erode(gray, gray, M);
cv.dilate(gray, opening, M);
cv.dilate(opening, coinsBg, M, new cv.Point(-1, -1), 3);
cv.distanceTransform(opening, distTrans, cv.DIST_L2, 5);
cv.normalize(distTrans, distTrans, 1, 0, cv.NORM_INF);
// get foreground
cv.threshold(distTrans, coinsFg, 0.7 * 1, 255, cv.THRESH_BINARY);
cv.imshow('canvasOutput', coinsFg);
src.delete(); dst.delete(); gray.delete(); opening.delete();
coinsBg.delete(); coinsFg.delete(); distTrans.delete(); M.delete();
</script>
<script type="text/javascript">
let utils = new Utils('errorMessage');
utils.loadCode('codeSnippet', 'codeEditor');
utils.loadImageToCanvas('coins.jpg', 'canvasInput');
utils.addFileInputHandler('fileInput', 'canvasInput');
let tryIt = document.getElementById('tryIt');
tryIt.addEventListener('click', () => {
utils.executeCode('codeEditor');
});
utils.loadOpenCv(() => {
tryIt.removeAttribute('disabled');
});
</script>
</body>
</html>