13-01-2012, 03:18 PM
Handwriting recognition
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Handwriting recognition is the ability of a computer to receive and interpret intelligible handwritten input from sources such as paper documents, photographs, touch-screens and other devices. The image of the written text may be sensed "off line" from a piece of paper by optical scanning (optical character recognition) or intelligent word recognition. Alternatively, the movements of the pen tip may be sensed "on line", for example by a pen-based computer screen surface.
Character recognition
After the extraction of individual characters occurs a recognition engine is used to identify the corresponding computer character. Several different recognition techniques are currently available.
Problem domain reduction techniques
Narrowing the problem domain often helps increase the accuracy of handwriting recognition systems. A form field for a ZIP code for example, would contain only the characters 0-9. This fact would reduce the number of possible identifications.
Primary techniques:
• Specifying specific character ranges
• Utilization of specialized forms
Neural networks
Neural network recognizers learn from an initial image training set. The trained network then makes the character identifications. Each neural network uniquely learns the properties that differentiate training images. It then looks for similar properties in the target image to be identified. Neural networks are quick to setup; however, they can be inaccurate if they learn properties that are not important in the target data.
Off-line recognition
Off-line handwriting recognition involves the automatic conversion of text in an image into letter codes which are usable within computer and text-processing applications. The data obtained by this form is regarded as a static representation of handwriting. Off-line handwriting recognition is comparatively difficult, as different people have different handwriting styles. And, as of today, OCR engines are primarily focused on machine printed text and ICR for hand "printed" text. There is no OCR/ICR engine that supports handwriting recognition as of today.