Optical character recognition - Wikipedia, the free encyclopedia. Optical character recognition (optical character reader, OCR) is the mechanical or electronic conversion of images of typed, handwritten or printed text into machine- encoded text, whether from a scanned document, a photo of a document, a scene- photo (for example the text on signs and billboards in a landscape photo) or from subtitle text superimposed on an image (for example from a television broadcast). It is a common method of digitising printed texts so that they can be electronically edited, searched, stored more compactly, displayed on- line, and used in machine processes such as cognitive computing, machine translation, (extracted) text- to- speech, key data and text mining.
OCR is a field of research in pattern recognition, artificial intelligence and computer vision. Early versions needed to be trained with images of each character, and worked on one font at a time. Advanced systems capable of producing a high degree of recognition accuracy for most fonts are now common, and with support for a variety of digital image file format inputs. In 1. 93. 1 he was granted USA Patent number 1,8.
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The patent was acquired by IBM. With the advent of smart- phones and smartglasses, OCR can be used in internet connected mobile device applications that extract text captured using the device's camera. These devices that do not have OCR functionality built- in to the operating system will typically use an OCR API to extract the text from the image file captured and provided by the device. Kurzweil decided that the best application of this technology would be to create a reading machine for the blind, which would allow blind people to have a computer read text to them out loud. This device required the invention of two enabling technologies . On January 1. 3, 1.
Kurzweil and the leaders of the National Federation of the Blind. Lexis. Nexis was one of the first customers, and bought the program to upload legal paper and news documents onto its nascent online databases. Two years later, Kurzweil sold his company to Xerox, which had an interest in further commercialising paper- to- computer text conversion. Xerox eventually spun it off as Scansoft, which merged with Nuance Communications. Ramakrishnan at the Medical intelligence and language engineering lab, Indian Institute of Science, has developed Print.
To. Braille tool, an open source GUI frontend. Google Books. Converting handwriting in real time to control a computer (pen computing)Defeating CAPTCHA anti- bot systems, though these are specifically designed to prevent OCR. Handwriting movement analysis can be used as input to handwriting recognition. This additional information can make the end- to- end process more accurate. This technology is also known as . The task of binarisation is performed as a simple way of separating the text (or any other desired image component) from the background. Especially important in multi- column layouts and tables.
Line and word detection . For proportional fonts, more sophisticated techniques are needed because whitespace between letters can sometimes be greater than that between words, and vertical lines can intersect more than one character. This relies on the input glyph being correctly isolated from the rest of the image, and on the stored glyph being in a similar font and at the same scale. This technique works best with typewritten text and does not work well when new fonts are encountered. This is the technique the early physical photocell- based OCR implemented, rather directly. Feature extraction decomposes glyphs into . These are compared with an abstract vector- like representation of a character, which might reduce to one or more glyph prototypes.
General techniques of feature detection in computer vision are applicable to this type of OCR, which is commonly seen in . The second pass is known as .
This is advantageous for unusual fonts or low- quality scans where the font is distorted (e. This technique can be problematic if the document contains words not in the lexicon, like proper nouns. Tesseract uses its dictionary to influence the character segmentation step, for improved accuracy. Beyond an application- specific lexicon, better performance can be had by taking into account business rules, standard expression. This strategy is called . These software can scan an image and extract words from the document. For any project related to paperless offices, the use of OCR tools will be required to achieve the objectives of paperless offices and homes.
These were often used in early matrix- matching systems. Users would need to learn how to write these special glyphs. Zone- based OCR restricts the image to a specific part of a document. This is often referred to as . Practical systems include the Amazon Mechanical Turk and re.
CAPTCHA. The National Library of Finland has developed an online interface for users correct OCRed texts in the standardised ALTO format. Department of Energy (DOE), the Information Science Research Institute (ISRI) had the mission to foster the improvement of automated technologies for understanding machine printed documents, and it conducted the most authoritative of the Annual Test of OCR Accuracy from 1. One study based on recognition of 1.
OCR accuracy for commercial OCR software varied from 8. The MNIST database is commonly used for testing systems' ability to recognise handwritten digits. Accuracy rates can be measured in several ways, and how they are measured can greatly affect the reported accuracy rate.
For example, if word context (basically a lexicon of words) is not used to correct software finding non- existent words, a character error rate of 1% (9. Accuracy rates of 8. Higher rates of recognition of general cursive script will likely not be possible without the use of contextual or grammatical information. For example, recognising entire words from a dictionary is easier than trying to parse individual characters from script. Reading the Amount line of a cheque (which is always a written- out number) is an example where using a smaller dictionary can increase recognition rates greatly.
The shapes of individual cursive characters themselves simply do not contain enough information to accurately (greater than 9. The history of OCR, optical character recognition.
Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences. Data processing magazine. MILE Lab, Dept of EE, IISc. Archived from the original on December 2.
Retrieved 7 December 2. IEEE Transactions on Pattern Analysis and Machine Intelligence. Journal of Electronic imaging.
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Document Analysis and Recognition (ICDAR) 2. International Conference on. Word Level Multi- script Identification. Pattern Recognition Letters, Vol.
Retrieved April 1. A., Zhu, S., Menietti, M., Crusan, J., Metelsky, I., Lakhani, K. International Journal on Document Analysis and Recognition. Analysing and Improving OCR Accuracy in Large Scale Historic Newspaper Digitisation Programs.
Retrieved 5 January 2. Future Challenges in Handwriting and Computer Applications. International Symposium on Handwriting and Computer Applications, Montreal, May 2.
OCR Software - Convert scanned images to Word, Excel, searchable PDF, HTML or other text formats without retyping. Show All Software in This Category. There are several OCR applications available to convert scanned images to. Word, HTML or searchable PDF. The differences between them can often. The main features that differentiate OCR applications are: We have tested the latest versions of.
Simple. OCR and have. ABBYY. Fine. Reader is the best overall value for business users, while.
Read. IRIS is the best. The key deciding factors were: User interface design. Page layout reconstruction capabilities.
Extensive language support. Stability of the engine when processing large documents. Quality and availability of technical support. Though other testing labs have ranked Omni. Page's overall accuracy slightly. All modern OCR. applications have very good accuracy, so we recommend going with the one that has.
ABBYY Fine. Reader's screenshot reader or Read. IRIS's Card. IRIS included in the Corporate version. For this reason. Scan. Store provides demo downloads for. OCR Software. with your Scan. Store User. Account.
Because of this variability and the subjectivity of user.