Optical Character Recognition in JS for Browser is based on ocrad.js. OCR for Browser is a free extension and You can use this application to extract text from any image you supply. Just upload your image files. OCR for Browser takes either a JPG, GIF, TIFF, BMP, PNG.
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Get OCR for Android (Beta release) - https://play.google.com/store/apps/details?id=com.ulm.ocr
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Add-on for Opera: http://bit.ly/1F0E0wP
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Release 1.0.1
For safety reasons, I disabled the possibility to import an image from url. Finally, I wish to inform you that you can write or draw directly on the canvas to get the subsequent character recognition and text extraction