53 research outputs found
Arabic Font Recognition Using Decision Trees Built From Common Words
We present an algorithm for a priori Arabic optical Font Recognition (AFR). The basic idea is to recognize fonts of some common Arabic words. Once these fonts are known, they can be generalized to lines, paragraphs, or neighbor non-common words since these components of a textual material almost have the same font. A decision tree is our approach to recognize Arabic fonts. A set of 48 features is used to learn the tree. These features include horizontal projections, Walsh coefficients, invariant moments, and geometrical attributes. A set of 36 fonts is investigated. The overall success rate is 90.8%. Some fonts show 100% success rate. The average time required to recognize the word font is approximately 0.30 seconds
Recognition of off-line handwritten cursive text
The author presents novel algorithms to design unconstrained handwriting
recognition systems organized in three parts:
In Part One, novel algorithms are presented for processing of Arabic text prior to
recognition. Algorithms are described to convert a thinned image of a stroke to a straight
line approximation. Novel heuristic algorithms and novel theorems are presented to
determine start and end vertices of an off-line image of a stroke. A straight line
approximation of an off-line stroke is converted to a one-dimensional representation by
a novel algorithm which aims to recover the original sequence of writing. The resulting
ordering of the stroke segments is a suitable preprocessed representation for subsequent
handwriting recognition algorithms as it helps to segment the stroke. The algorithm was
tested against one data set of isolated handwritten characters and another data set of
cursive handwriting, each provided by 20 subjects, and has been 91.9% and 91.8%
successful for these two data sets, respectively.
In Part Two, an entirely novel fuzzy set-sequential machine character recognition
system is presented. Fuzzy sequential machines are defined to work as recognizers of
handwritten strokes. An algorithm to obtain a deterministic fuzzy sequential machine from
a stroke representation, that is capable of recognizing that stroke and its variants, is
presented. An algorithm is developed to merge two fuzzy machines into one machine. The
learning algorithm is a combination of many described algorithms. The system was tested
against isolated handwritten characters provided by 20 subjects resulting in 95.8%
recognition rate which is encouraging and shows that the system is highly flexible in
dealing with shape and size variations.
In Part Three, also an entirely novel text recognition system, capable of recognizing
off-line handwritten Arabic cursive text having a high variability is presented. This system
is an extension of the above recognition system. Tokens are extracted from a onedimensional
representation of a stroke. Fuzzy sequential machines are defined to work as
recognizers of tokens. It is shown how to obtain a deterministic fuzzy sequential machine
from a token representation that is capable'of recognizing that token and its variants. An
algorithm for token learning is presented. The tokens of a stroke are re-combined to
meaningful strings of tokens. Algorithms to recognize and learn token strings are
described. The. recognition stage uses algorithms of the learning stage. The process of
extracting the best set of basic shapes which represent the best set of token strings that
constitute an unknown stroke is described. A method is developed to extract lines from
pages of handwritten text, arrange main strokes of extracted lines in the same order as
they were written, and present secondary strokes to main strokes. Presented secondary
strokes are combined with basic shapes to obtain the final characters by formulating and
solving assignment problems for this purpose. Some secondary strokes which remain
unassigned are individually manipulated. The system was tested against the handwritings
of 20 subjects yielding overall subword and character recognition rates of 55.4% and
51.1%, respectively
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