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Preparation

All files referenced and other helpful information is posted on this site at the GitHub link. The GitHub link also has 3 Python files, which is our completed OCR software. This tutorial serves as a walkthrough of the code under recognitionScript.py, where more in-depth explanations are discussed in the provided .py files.

This tutorial uses Python 2.7, Numpy, and OpenCV for the software development portions. The instructions for downloading OpenCV for Linux can be found at this link. For windows, go to to opencv.org For Numpy, visit numpy.org For Python, visit python.org

We assume the reader will have been exposed to Python before. If not, a general understanding of Python IO and the ability to look up Python documentation is preferable.

Preprocessing

For our tutorial, we will make a few assumptions for our input images. First off, the image will only have printed text. We also assume the image will be a png. For example, we will have pictures similar to the figure below. Sample image Because this is an introduction, there will not be information on transforming and translating, as this involves verbose algorithms beyond the scope of our knowledge.

Second, images may contain the full range of colors.

The first step is to read in the image we will be performing OCR on. OpenCV has the ability to do this with imread() function. We have made a wrapper function that does this and returns a copy, which will be necessary for some OpenCV functions

Reading in image

Right now, im is an image, which can be represented as a matrix with pixels. Each pixel is some object with 3 values, red, blue, green(rgb). In order to make this compatible with future functions, we will convert the image to grayscale. This involves a function provided by OpenCV, which process the rgb values and replace the pixel with some intensity value. The next step is to convert the image into grayscale. Open Cv has a color converting function called Cv2.cvtColor(image, code ) which can map one type of color to another based on the input code. For the purposes of converting our image into grayscale we use the parameter Cv2.COLOR_BGR2GRAY and call our the helper function color2gray, which returns the grayscaled image.

Convering color to gray

Greyscale Above is our grayscaled image.

Filtering

Next, we will need to apply a filter onto the image. Depending on the task, we could use many different filters to achieve a certain goal. We want to filter our image to increase our ability to detect edges; this allows us to identify characters in the image. Therefore, we will be covering the Gaussian, Laplacian, and Sobel filters.

Gaussian filter

Using the following formula, we will create some n by n matrix to build the Gaussian filter.

gaussss

The Gaussian filter is effective towards noisy signals, because of its characteristic as also being a low pass filter. By blurring the image to a small degree, we allow any sensitive edge detection algorithms to not mistake noise to be something of significance.

Laplace

In cases where we know that noise is not an issue, we can use the Laplacian filer. Rather than worry about reducing noise, the Laplace filter's purpose is to enhance edges by sharpening the image. The formula to describe the filter is

Questions & Answers

where we get a research paper on Nano chemistry....?
Maira Reply
nanopartical of organic/inorganic / physical chemistry , pdf / thesis / review
Ali
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
Google
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
hey
Giriraj
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
revolt
da
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
ya I also want to know the raman spectra
Bhagvanji
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
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Source:  OpenStax, Introduction to optical character recognition. OpenStax CNX. Dec 17, 2014 Download for free at http://legacy.cnx.org/content/col11728/1.1
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