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optical character recognition using artificial neural network - ijater

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International Journal of Advanced Technology & Engineering Research (IJATER)<br />

OPTICAL CHARACTER RECOGNITION USING<br />

ARTIFICIAL NEURAL NETWORK<br />

Sameeksha Barve, computer science department, Jawaharlal institute of technology borawan, khargone (m.p)<br />

Email- Sameekshabarve69@gmail.com, vinibarve1889@gmail.com<br />

Abstract<br />

Optical <strong>character</strong> <strong>recognition</strong> refers to the process of translat<br />

ing images of hand-written, typewritten, or printed text into a<br />

format understood by machines for the purpose of editing,<br />

indexing/searching, and a reduction in storage size. Optical<br />

<strong>character</strong> <strong>recognition</strong> is the mechanical or electronic translation<br />

of images of handwritten, typewritten or printed text<br />

into machine-editable text. Artificial <strong>neural</strong> <strong>network</strong>s are<br />

commonly used to perform <strong>character</strong> <strong>recognition</strong> due to their<br />

high noise tolerance. In this paper, an Optical <strong>character</strong> <strong>recognition</strong><br />

based on Artificial Neural Networks (ANNs). The<br />

ANN is trained <strong>using</strong> the Back Propagation algorithm.<br />

Introduction<br />

Optical Character Recognition, or OCR, is the process of<br />

translating images of handwritten, typewritten, or printed<br />

text into a format understood by machines for the purpose of<br />

editing, indexing/searching, and a reduction in storage size.<br />

Optical Character Recognition that would use an Artificial<br />

Neural Network as the backend to solve the classification<br />

problem. OCR is a field of research in pattern <strong>recognition</strong>,<br />

<strong>artificial</strong> intelligence and machine vision. Though academic<br />

research in the field continues, the focus on OCR has shifted<br />

to implementation of proven techniques. The input for the<br />

OCR problem is pages of scanned text. To perform the <strong>character</strong><br />

<strong>recognition</strong>, our application has to go through three<br />

important steps. The first is segmentation, i.e., given a binary<br />

input image, to identify the individual glyphs (basic<br />

units representing one or more <strong>character</strong>s, usually contiguous).<br />

The second step is feature extraction, i.e., to compute<br />

from each glyph a vector of numbers that will serve as<br />

input features for an ANN. This step is the most difficult in<br />

the sense that there is no obvious way to obtain these features.<br />

The final task is classification. In our approach, there<br />

are two parts to this. The first is the training phase, where we<br />

manually identify the correct class of several glyphs. One of<br />

the most classical applications of the Artificial Neural Network<br />

is the Character Recognition System. This system is<br />

the base for many different types of applications in various<br />

fields, many of which we use in our daily lives. Cost effective<br />

and less time consuming, businesses, post offices,<br />

banks, security systems, and even the field of robotics employ<br />

this system as the base of their operations.<br />

Steps of OCR<br />

Optical Character Recognition (OCR) Using Artificial Neural<br />

Network is basically in the field of research. To gain better<br />

knowledge, techniques and solutions regarding the procedures<br />

that we want to follow, we studied the various research<br />

papers on existing OCR systems. All these study<br />

helped us with clarifying our target goals. The basic steps<br />

involved in Optical Character Recognition are:-<br />

1. Image Acquisition<br />

2. Preprocessing<br />

3. Document Page Analysis<br />

4. Feature Extraction<br />

5. Training and Recognition<br />

6. Post Processing<br />

Figure 1. Steps of OCR<br />

Different Areas of Character Recognition<br />

Optical Character Recognition deals with the problem of<br />

recognizing <strong>optical</strong>ly processed <strong>character</strong>s. Optical <strong>recognition</strong><br />

is performed off-line after the writing or printing has<br />

been completed, as opposed to on-line <strong>recognition</strong> where the<br />

computer recognizes the <strong>character</strong>s as they are drawn. Both<br />

hand printed and printed <strong>character</strong>s may be recognized, but<br />

the performance is directly dependent upon the quality of the<br />

input documents.<br />

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International Journal of Advanced Technology & Engineering Research (IJATER)<br />

The second branch of reading machines is that of page<br />

readers for text entry, mainly used in office automation.<br />

Here the restrictions <strong>character</strong> set is exchanged for constraints<br />

concerning font and printing quality. The reading<br />

machines are used to enter large amounts of text, often<br />

in a word processing environment. These page readers<br />

are in strong competition with direct key-input and<br />

electronic exchange of data. This area of application is<br />

therefore of diminishing importance.<br />

3. Process Automation: -<br />

This is actually the technology of automatic address<br />

reading for mail sorting. Hence, the goal is to direct<br />

each letter into the appropriate bin regardless of whether<br />

each <strong>character</strong> was correctly recognized or not. The<br />

general approach is to read all the information available<br />

and use the postcode as a redundancy check.<br />

Figure 2. Areas of Character Recognition<br />

The more constrained the input is, the better will the performance<br />

of the OCR system be. However, when it comes to<br />

totally unconstrained handwriting, OCR machines are still a<br />

long way from reading as well as humans. However, the<br />

computer reads fast and technical advances are continually<br />

bringing the technology closer to its ideal.<br />

Applications of OCR<br />

Algorithm Used For Optical Character<br />

Recognition<br />

One of the most typical problems to which a <strong>neural</strong> <strong>network</strong><br />

is applied is that of <strong>optical</strong> <strong>character</strong> <strong>recognition</strong>. Recognizing<br />

<strong>character</strong>s is a problem that at first seems extremely<br />

simple- but it's extremely difficult in practice to program a<br />

computer to do it. And yet, automated <strong>character</strong> <strong>recognition</strong><br />

is of vital importance in many industries such as banking<br />

and shipping. The U.S. post office uses an automatic scanning<br />

system to recognize the digits in ZIP codes. We may<br />

have used scanning software that can take an image of a<br />

printed page and generate an ASCII document from it. These<br />

devices work by simulating a type of <strong>neural</strong> <strong>network</strong> known<br />

as a back propagation <strong>network</strong>.<br />

Three main application areas are commonly distinguished;<br />

data entry, text entry and process automation<br />

1. Data Entry:-<br />

This area covers technologies for entering large<br />

amounts of restricted data. Initially such document reading<br />

machines were used for banking applications. The<br />

systems are <strong>character</strong>ized by reading only an extremely<br />

limited set of printed <strong>character</strong>s, usually numerals and a<br />

few special symbols. They are designed to read data like<br />

account numbers, customer’s identification, article<br />

numbers, amounts of money etc.<br />

2. Text Entry:-<br />

Figure 3. Back propagation Network Architecture<br />

A Back Propagation <strong>network</strong> learns by example. We give<br />

the algorithm examples of what we want the <strong>network</strong> to do<br />

and it changes the <strong>network</strong>’s weights so that, when training<br />

is finished, it will give the required output for a particular<br />

input. Back Propagation <strong>network</strong>s are ideal for simple Pattern<br />

Recognition and Mapping Tasks As just mentioned, to<br />

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International Journal of Advanced Technology & Engineering Research (IJATER)<br />

train the <strong>network</strong> we need to give it examples of what we<br />

want the output (called the Target ) for a particular input as<br />

shown in Figure 3.<br />

.<br />

An Artificial Neural Network (ANN), usually called <strong>neural</strong><br />

<strong>network</strong> (NN), is a mathematical model or computational<br />

model that is inspired by the structure and/or functional aspects<br />

of biological <strong>neural</strong> <strong>network</strong>s. A <strong>neural</strong> <strong>network</strong> consists<br />

of an interconnected group of <strong>artificial</strong> neurons, and it<br />

processes information <strong>using</strong> a connectionist approach<br />

to computation. In most cases an ANN is an adaptive system<br />

that changes its structure based on external or internal<br />

information that flows through the <strong>network</strong> during the learning<br />

phase. Modern <strong>neural</strong> <strong>network</strong>s are nonlinear<br />

statistical data modeling tools. They are usually used<br />

to model complex relationships between inputs and outputs<br />

or to find patterns in data. An <strong>artificial</strong> <strong>neural</strong> <strong>network</strong><br />

(ANN), usually called “<strong>neural</strong> <strong>network</strong>” (NN), is a mathematical<br />

model or computational model that tries to simulate<br />

the structure and/or functional aspects of biological <strong>neural</strong><br />

<strong>network</strong>s. It consists of an interconnected group of <strong>artificial</strong><br />

neurons and processes information <strong>using</strong> a connectionist<br />

approach to computation. In most cases an ANN is an adaptive<br />

system that changes its structure based on external or<br />

internal information that flows through the <strong>network</strong> during<br />

the learning phase.<br />

Figure 4. Back propagation Training Set<br />

So, if we put in the first pattern to the <strong>network</strong>, we would<br />

like the output to be 0 1 as shown in figure 4 (a black pixel is<br />

represented by 1 and a white by 0 .The input and its corresponding<br />

target are called a Training Pair.<br />

Figure 6. Artificial <strong>neural</strong> <strong>network</strong><br />

Figure 5. Applying a training pair to a <strong>network</strong><br />

Many of today's document scanners for the PC come with<br />

software that performs a task known as <strong>optical</strong> <strong>character</strong><br />

<strong>recognition</strong> (OCR). OCR software allows we to scan in a<br />

printed document and then convert the scanned image into to<br />

an electronic text format such as a Word document, enabling<br />

you to manipulate the text. In order to perform this conversion<br />

the software must analyze each group of pixels (0's and<br />

1's) that form a letter and produce a value that corresponds to<br />

that letter. Some of the OCR software on the market use a<br />

<strong>neural</strong> <strong>network</strong> as the classification engine.<br />

Artificial Neural Network<br />

ISSN NO: 2250-3536 VOLUME 2, ISSUE 2, MAY 2012 141


International Journal of Advanced Technology & Engineering Research (IJATER)<br />

Figure 7 .Example of OCR<br />

Conclusion<br />

At the current stage of development, the software does perform<br />

well either in terms of speed or accuracy but not better.<br />

It is unlikely to replace existing OCR methods, especially<br />

for English text. Artificial <strong>neural</strong> <strong>network</strong>s are commonly<br />

used to perform <strong>character</strong> <strong>recognition</strong> due to their high noise<br />

tolerance. The systems have the ability to yield excellent<br />

results. The feature extraction step of <strong>optical</strong> <strong>character</strong> <strong>recognition</strong><br />

is the most important. A poorly chosen set of features<br />

will yield poor classification rates by any <strong>neural</strong> <strong>network</strong>.<br />

References<br />

[1] Optical Character Recognition <strong>using</strong> Artificial Neural<br />

Networks Rakesh Bhujade, BLB-International Journal of<br />

Science & Technology Vol.1, No. 2 (2010), 143-152 (ISSN<br />

0976-3074)<br />

[2] Character Recognition Using Neural Networks by Near<br />

East University, North Cyprus, Turkey via Mersin-10,<br />

KKTC<br />

[3] Some Considerations on the Limitations of Image<br />

Processing Computer Architectures by Michael J. B. Duff,<br />

Department of Physics and Astronomy University College<br />

London Gower Street, London WClE 6BT<br />

[4] Optical <strong>character</strong> <strong>recognition</strong> by The Association for<br />

Automatic Identification and Data Capture Technologies<br />

[5] Online Handwritten Character Recognition Using<br />

an Optical Back propagation Neural Network by Walid A.<br />

Salameh Princess Summaya University for Science and<br />

Technology, Amman, Jordan<br />

ISSN NO: 2250-3536 VOLUME 2, ISSUE 2, MAY 2012 142

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