code-boxx/0-JS-OCR.MD

## 0-JS-OCR.MD

      
    Raw
  

              0-JS-OCR.MD
            
          
    JAVASCRIPT IMAGE TO TEXT WITH OCR


https://code-boxx.com/javascript-ocr-image-to-text/
https://youtu.be/znsqLxIp3Gk
https://github.com/naptha/tesseract.js

TEST IMAGE


LICENSE

Copyright by Code Boxx
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

  
## 1-select.html
<!DOCTYPE html>
<html>
  <head>
    <title>Image To Text - Select From File</title>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no">
    <link rel="stylesheet" href="x-dummy.css">

    <!-- (A) LOAD TESSERACT & JS -->
    <!-- https://cdnjs.com/libraries/tesseract.js -->
    <script defer src="https://cdnjs.cloudflare.com/ajax/libs/tesseract.js/4.1.1/tesseract.min.js"></script>
    <script defer src="1-select.js"></script>
  </head>
  <body>
    <!-- (B) FILE SELECTOR & RESULT -->
    <input type="file" id="select" accept="image/png, image/gif, image/webp, image/jpeg">
    <textarea id="result"></textarea>
  </body>
</html>

## 1-select.js
window.addEventListener("load", async () => {
  // (A) GET HTML ELEMENTS
  const hSel = document.getElementById("select"),
        hRes = document.getElementById("result");

  // (B) CREATE ENGLISH TESSERACT WORKER
  const worker = await Tesseract.createWorker();
  await worker.loadLanguage("eng");
  await worker.initialize("eng");

  // (C) ON FILE SELECT - IMAGE TO TEXT
  hSel.onchange = async () => {
    const res = await worker.recognize(hSel.files[0]);
    hRes.value = res.data.text;
  };
});

## 2-fetch.html
<!DOCTYPE html>
<html>
  <head>
    <title>Image To Text - Fetch</title>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no">
    <link rel="stylesheet" href="x-dummy.css">

    <!-- (A) LOAD TESSERACT & JS -->
    <!-- https://cdnjs.com/libraries/tesseract.js -->
    <script defer src="https://cdnjs.cloudflare.com/ajax/libs/tesseract.js/4.1.1/tesseract.min.js"></script>
    <script defer src="2-fetch.js"></script>
  </head>
  <body>
    <!-- (B) RESULT -->
    <textarea id="result"></textarea>
  </body>
</html>

## 2-fetch.js
window.addEventListener("load", () => {
  // (A) FETCH IMAGE
  fetch("text.png")
  .then(res => res.blob())
  .then(async (blob) => {
    // (B) CREATE ENGLISH TESSERACT WORKER
    const worker = await Tesseract.createWorker();
    await worker.loadLanguage("eng");
    await worker.initialize("eng");

    // (C) RESULT
    const res = await worker.recognize(blob);
    document.getElementById("result").value = res.data.text;
  })
  .catch(err => console.error(err));
});

## 3-cam.html
<!DOCTYPE html>
<html>
  <head>
    <title>Image To Text - Webcam</title>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no">
    <link rel="stylesheet" href="x-dummy.css">

    <!-- (A) LOAD TESSERACT & JS -->
    <!-- https://cdnjs.com/libraries/tesseract.js -->
    <script defer src="https://cdnjs.cloudflare.com/ajax/libs/tesseract.js/4.1.1/tesseract.min.js"></script>
    <script defer src="3-cam.js"></script>
  </head>
  <body>
    <!-- (B) WEBCAM & RESULT -->
    <video id="vid" autoplay></video>
    <button id="go">Go!</button>
    <textarea id="result"></textarea>
  </body>
</html>

## 3-cam.js
var webkam = {
  // (A) INITIALIZE
  worker : null, // tesseract worker
  hVid : null, hGo :null, hRes : null, // html elements
  init : () => {
    // (A1) GET HTML ELEMENTS
    webkam.hVid = document.getElementById("vid"),
    webkam.hGo = document.getElementById("go"),
    webkam.hRes = document.getElementById("result");

    // (A2) GET USER PERMISSION TO ACCESS CAMERA
    navigator.mediaDevices.getUserMedia({ video: true })
    .then(async (stream) => {
      // (A2-1) CREATE ENGLISH TESSERACT WORKER
      webkam.worker = await Tesseract.createWorker();
      await webkam.worker.loadLanguage("eng");
      await webkam.worker.initialize("eng");

      // (A2-2) WEBCAM LIVE STREAM
      webkam.hVid.srcObject = stream;
      webkam.hGo.onclick = webkam.snap;
    })
    .catch(err => console.error(err));
  },

  // (B) SNAP VIDEO FRAME TO TEXT
  snap : async () => {
    // (B1) CREATE NEW CANVAS
    let canvas = document.createElement("canvas"),
        ctx = canvas.getContext("2d"),
        vWidth = webkam.hVid.videoWidth,
        vHeight = webkam.hVid.videoHeight;

    // (B2) CAPTURE VIDEO FRAME TO CANVAS
    canvas.width = vWidth;
    canvas.height = vHeight;
    ctx.drawImage(webkam.hVid, 0, 0, vWidth, vHeight);

    // (B3) CANVAS TO IMAGE, IMAGE TO TEXT
    const res = await webkam.worker.recognize(canvas.toDataURL("image/png"));
    webkam.hRes.value = res.data.text;
  },
};
window.addEventListener("load", webkam.init);

## x-dummy.css
/* NOT IMPORTANT - COSMETICS */
* { font-family: Arial, Helvetica, sans-serif; box-sizing: border-box; }
body { max-width: 600px; margin: 0 auto; padding: 10px; }
#select, #result, #vid, #go { width: 100%; padding: 10px; margin: 5px 0; }
#select { border: 1px solid #ffb6b6; background: #ffe7e7; }
#result { resize: none; height: 100px; border: 1px solid #c0bfff; background: #dceaff; }
#vid { height: 400px; }
#go { color: #fff; background: #5145b5; border: 0; cursor: pointer; }
	<!DOCTYPE html>
	<html>
	<head>
	<title>Image To Text - Select From File</title>
	<meta charset="utf-8">
	<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no">
	<link rel="stylesheet" href="x-dummy.css">

	<!-- (A) LOAD TESSERACT & JS -->
	<!-- https://cdnjs.com/libraries/tesseract.js -->
	<script defer src="https://cdnjs.cloudflare.com/ajax/libs/tesseract.js/4.1.1/tesseract.min.js"></script>
	<script defer src="1-select.js"></script>
	</head>
	<body>
	<!-- (B) FILE SELECTOR & RESULT -->
	<input type="file" id="select" accept="image/png, image/gif, image/webp, image/jpeg">
	<textarea id="result"></textarea>
	</body>
	</html>
	window.addEventListener("load", async () => {
	// (A) GET HTML ELEMENTS
	const hSel = document.getElementById("select"),
	hRes = document.getElementById("result");

	// (B) CREATE ENGLISH TESSERACT WORKER
	const worker = await Tesseract.createWorker();
	await worker.loadLanguage("eng");
	await worker.initialize("eng");

	// (C) ON FILE SELECT - IMAGE TO TEXT
	hSel.onchange = async () => {
	const res = await worker.recognize(hSel.files[0]);
	hRes.value = res.data.text;
	};
	});
	window.addEventListener("load", () => {
	// (A) FETCH IMAGE
	fetch("text.png")
	.then(res => res.blob())
	.then(async (blob) => {
	// (B) CREATE ENGLISH TESSERACT WORKER
	const worker = await Tesseract.createWorker();
	await worker.loadLanguage("eng");
	await worker.initialize("eng");

	// (C) RESULT
	const res = await worker.recognize(blob);
	document.getElementById("result").value = res.data.text;
	})
	.catch(err => console.error(err));
	});
	var webkam = {
	// (A) INITIALIZE
	worker : null, // tesseract worker
	hVid : null, hGo :null, hRes : null, // html elements
	init : () => {
	// (A1) GET HTML ELEMENTS
	webkam.hVid = document.getElementById("vid"),
	webkam.hGo = document.getElementById("go"),
	webkam.hRes = document.getElementById("result");

	// (A2) GET USER PERMISSION TO ACCESS CAMERA
	navigator.mediaDevices.getUserMedia({ video: true })
	.then(async (stream) => {
	// (A2-1) CREATE ENGLISH TESSERACT WORKER
	webkam.worker = await Tesseract.createWorker();
	await webkam.worker.loadLanguage("eng");
	await webkam.worker.initialize("eng");

	// (A2-2) WEBCAM LIVE STREAM
	webkam.hVid.srcObject = stream;
	webkam.hGo.onclick = webkam.snap;
	})
	.catch(err => console.error(err));
	},

	// (B) SNAP VIDEO FRAME TO TEXT
	snap : async () => {
	// (B1) CREATE NEW CANVAS
	let canvas = document.createElement("canvas"),
	ctx = canvas.getContext("2d"),
	vWidth = webkam.hVid.videoWidth,
	vHeight = webkam.hVid.videoHeight;

	// (B2) CAPTURE VIDEO FRAME TO CANVAS
	canvas.width = vWidth;
	canvas.height = vHeight;
	ctx.drawImage(webkam.hVid, 0, 0, vWidth, vHeight);

	// (B3) CANVAS TO IMAGE, IMAGE TO TEXT
	const res = await webkam.worker.recognize(canvas.toDataURL("image/png"));
	webkam.hRes.value = res.data.text;
	},
	};
	window.addEventListener("load", webkam.init);
	/* NOT IMPORTANT - COSMETICS */
	* { font-family: Arial, Helvetica, sans-serif; box-sizing: border-box; }
	body { max-width: 600px; margin: 0 auto; padding: 10px; }
	#select, #result, #vid, #go { width: 100%; padding: 10px; margin: 5px 0; }
	#select { border: 1px solid #ffb6b6; background: #ffe7e7; }
	#result { resize: none; height: 100px; border: 1px solid #c0bfff; background: #dceaff; }
	#vid { height: 400px; }
	#go { color: #fff; background: #5145b5; border: 0; cursor: pointer; }