<!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>Image Bitwise Example</title> <link href="js_example_style.css" rel="stylesheet" type="text/css" /> </head> <body> <h2>Image Bitwise Example</h2> <p> <canvas> elements named <b>imageCanvasInput</b>, <b>logoCanvasInput</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="imageCanvasInput"></canvas> </td> <td> <canvas id="canvasOutput"></canvas> </td> </tr> <tr> <td> <div class="caption">imageCanvasInput <input type="file" id="imageFileInput" name="file" accept="image/*" /></div> </td> <td> <div class="caption">canvasOutput</div> </td> </tr> <tr> <td> <canvas id="logoCanvasInput"></canvas> </td> <td> </td> </tr> <tr> <td> <div class="caption">logoCanvasInput <input type="file" id="logoFileInput" name="file" accept="image/*" /></div> </td> <td> </td> </tr> </table> </div> <script src="utils.js" type="text/javascript"></script> <script id="codeSnippet" type="text/code-snippet"> let src = cv.imread('imageCanvasInput'); let logo = cv.imread('logoCanvasInput'); let dst = new cv.Mat(); let roi = new cv.Mat(); let mask = new cv.Mat(); let maskInv = new cv.Mat(); let imgBg = new cv.Mat(); let imgFg = new cv.Mat(); let sum = new cv.Mat(); let rect = new cv.Rect(0, 0, logo.cols, logo.rows); // I want to put logo on top-left corner, So I create a ROI roi = src.roi(rect); // Create a mask of logo and create its inverse mask also cv.cvtColor(logo, mask, cv.COLOR_RGBA2GRAY, 0); cv.threshold(mask, mask, 100, 255, cv.THRESH_BINARY); cv.bitwise_not(mask, maskInv); // Black-out the area of logo in ROI cv.bitwise_and(roi, roi, imgBg, maskInv); // Take only region of logo from logo image cv.bitwise_and(logo, logo, imgFg, mask); // Put logo in ROI and modify the main image cv.add(imgBg, imgFg, sum); dst = src.clone(); for (let i = 0; i < logo.rows; i++) { for (let j = 0; j < logo.cols; j++) { dst.ucharPtr(i, j)[0] = sum.ucharPtr(i, j)[0]; } } cv.imshow('canvasOutput', dst); src.delete(); dst.delete(); logo.delete(); roi.delete(); mask.delete(); maskInv.delete(); imgBg.delete(); imgFg.delete(); sum.delete(); </script> <script type="text/javascript"> let utils = new Utils('errorMessage'); utils.loadCode('codeSnippet', 'codeEditor'); utils.loadImageToCanvas('lena.jpg', 'imageCanvasInput'); utils.loadImageToCanvas('lenaFace.png', 'logoCanvasInput'); utils.addFileInputHandler('imageFileInput', 'imageCanvasInput'); utils.addFileInputHandler('logoFileInput', 'logoCanvasInput'); let tryIt = document.getElementById('tryIt'); tryIt.addEventListener('click', () => { utils.executeCode('codeEditor'); }); utils.loadOpenCv(() => { tryIt.removeAttribute('disabled'); }); </script> </body> </html>