118 research outputs found
Recognition of Cursive Arabic Handwritten Text using Embedded Training based on HMMs
In this paper we present a system for offline recognition cursive Arabic handwritten text based on Hidden Markov Models HMMs The system is analytical without explicit segmentation used embedded training to perform and enhance the character models Extraction features preceded by baseline estimation are statistical and geometric to integrate both the peculiarities of the text and the pixel distribution characteristics in the word image These features are modelled using hidden Markov models and trained by embedded training The experiments on images of the benchmark IFN ENIT database show that the proposed system improves recognitio
Recognition of Cursive Arabic Handwritten Text using Embedded Training based on HMMs
In this paper we present a system for offline recognition cursive Arabic handwritten text based on Hidden Markov Models (HMMs). The system is analytical without explicit segmentation used embedded training to perform and enhance the character models. Extraction features preceded by baseline estimation are statistical and geometric to integrate both the peculiarities of the text and the pixel distribution characteristics in the word image. These features are modelled using hidden Markov models and trained by embedded training. The experiments on images of the benchmark IFN/ENIT database show that the proposed system improves recognition
Unconstrained Scene Text and Video Text Recognition for Arabic Script
Building robust recognizers for Arabic has always been challenging. We
demonstrate the effectiveness of an end-to-end trainable CNN-RNN hybrid
architecture in recognizing Arabic text in videos and natural scenes. We
outperform previous state-of-the-art on two publicly available video text
datasets - ALIF and ACTIV. For the scene text recognition task, we introduce a
new Arabic scene text dataset and establish baseline results. For scripts like
Arabic, a major challenge in developing robust recognizers is the lack of large
quantity of annotated data. We overcome this by synthesising millions of Arabic
text images from a large vocabulary of Arabic words and phrases. Our
implementation is built on top of the model introduced here [37] which is
proven quite effective for English scene text recognition. The model follows a
segmentation-free, sequence to sequence transcription approach. The network
transcribes a sequence of convolutional features from the input image to a
sequence of target labels. This does away with the need for segmenting input
image into constituent characters/glyphs, which is often difficult for Arabic
script. Further, the ability of RNNs to model contextual dependencies yields
superior recognition results.Comment: 5 page
Does color modalities affect handwriting recognition? An empirical study on Persian handwritings using convolutional neural networks
Most of the methods on handwritten recognition in the literature are focused
and evaluated on Black and White (BW) image databases. In this paper we try to
answer a fundamental question in document recognition. Using Convolutional
Neural Networks (CNNs), as eye simulator, we investigate to see whether color
modalities of handwritten digits and words affect their recognition accuracy or
speed? To the best of our knowledge, so far this question has not been answered
due to the lack of handwritten databases that have all three color modalities
of handwritings. To answer this question, we selected 13,330 isolated digits
and 62,500 words from a novel Persian handwritten database, which have three
different color modalities and are unique in term of size and variety. Our
selected datasets are divided into training, validation, and testing sets.
Afterwards, similar conventional CNN models are trained with the training
samples. While the experimental results on the testing set show that CNN on the
BW digit and word images has a higher performance compared to the other two
color modalities, in general there are no significant differences for network
accuracy in different color modalities. Also, comparisons of training times in
three color modalities show that recognition of handwritten digits and words in
BW images using CNN is much more efficient
Ensemble learning using multi-objective optimisation for arabic handwritten words
Arabic handwriting recognition is a dynamic and stimulating field of study within
pattern recognition. This system plays quite a significant part in today's global
environment. It is a widespread and computationally costly function due to cursive
writing, a massive number of words, and writing style. Based on the literature, the
existing features lack data supportive techniques and building geometric features.
Most ensemble learning approaches are based on the assumption of linear
combination, which is not valid due to differences in data types. Also, the existing
approaches of classifier generation do not support decision-making for selecting the
most suitable classifier, and it requires enabling multi-objective optimisation to handle
these differences in data types. In this thesis, new type of feature for handwriting using
Segments Interpolation (SI) to find the best fitting line in each of the windows with a
model for finding the best operating point window size for SI features. Multi-Objective
Ensemble Oriented (MOEO) formulated to control the classifier topology and provide
feedback support for changing the classifiers' topology and weights based on the
extension of Non-dominated Sorting Genetic Algorithm (NSGA-II). It is designated
as the Random Subset based Parents Selection (RSPS-NSGA-II) to handle neurons
and accuracy. Evaluation metrics from two perspectives classification and Multiobjective
optimization. The experimental design based on two subsets of the
IFN/ENIT database. The first one consists of 10 classes (C10) and 22 classes (C22).
The features were tested with Support Vector Machine (SVM) and Extreme Learning
Machine (ELM). This work improved due to the SI feature. SI shows a significant
result with SVM with 88.53% for C22. RSPS for C10 at k=2 achieved 91% accuracy
with fewer neurons than NSGA-II, and for C22 at k=10, accuracy has been increased
81% compared to NSGA-II 78%. Future work may consider introducing more features
to the system, applying them to other languages, and integrating it with sequence
learning for more accuracy
Arabic Handwritten Word Recognition based on Bernoulli Mixture HMMs
This thesis presents new approaches in off-line Arabic Handwriting Recognition based on
conventional Bernoulli Hidden Markov models. Until now, the off-line handwriting
recognition, in particular, the Arabic handwriting recognition is still far away form being
perfect. Hidden Markov Models (HMMs) are now widely used for off-line handwriting
recognition in many languages and, in particular, in Arabic. As in speech recognition, they
are usually built from shared, embedded HMMs at symbol level, in which state-conditional
probability density functions are modeled with Gaussian mixtures. In contrast to speech
recognition, however, it is unclear which kind of features should be used and, indeed, very
different features sets are in use today. Among them, we have recently proposed to simply
use columns of raw, binary image pixels, which are directly fed into embedded Bernoulli
(mixture) HMMs, that is, embedded HMMs in which the emission probabilities are modeled
with Bernoulli mixtures. The idea is to by-pass feature extraction and ensure that no
discriminative information is filtered out during feature extraction, which in some sense is
integrated into the recognition model. In this thesis, we review this idea along with some
extensions that are currently providing state-of-the-art results on Arabic handwritten word
recognition.Alkhoury, I. (2010). Arabic Handwritten Word Recognition based on Bernoulli Mixture HMMs. http://hdl.handle.net/10251/11478Archivo delegad
A discrete hidden Markov model for the recognition of handwritten Farsi words
Handwriting recognition systems (HRS) have been researched for more than 50 years. Designing a system to recognize specific words in a handwritten clean document is still a difficult task and the challenge is to achieve a high recognition rate. Previously, most of the research in the handwriting recognition domain was conducted on Chinese and Latin languages, while recently more people have shown an interest in the Indo-Iranian script recognition systems. In this thesis, we present an automatic handwriting recognition system for Farsi words. The system was trained, validated and tested on the CENPARMI Farsi Dataset, which was gathered during this research. CENPARMI's Farsi Dataset is unique in terms of its huge number of images (432,357 combined grayscale and binary), inclusion of all possible handwriting types (Dates, Words, Isolated Characters, Isolated Digits, Numeral Strings, Special Symbols, Documents), the variety of cursive styles, the number of writers (400) and the exclusive participation of Native Farsi speakers in the gathering of data. The words were first preprocessed. Concavity and Distribution features were extracted and the codebook was calculated by the vector quantization method. A Discrete Hidden Markov Model was chosen as the classifier because of the cursive nature of the Farsi script. Finally, encouraging recognition rates of98.76% and 96.02% have been obtained for the Training and Testing sets, respectivel
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