Precise Prediction of COVID-19 in Chest X-Ray
Images Using KE Sieve Algorithm
S Sai Thejeshwar 1
Chaitanya Chokkareddy 1
Dr. K Eswaran 1, 2
—The novel coronavirus (COVID-19)
pandemic is pressurizing the healthcare systems across
the globe and few of them are on the verge of failing. The
detection of this virus as early as possible will help in
contaminating the spread of it as the virus is mutating
itself as fast as possible and currently there are about
4,300 strains of the virus according to the reports.
Clinical studies have shown that most of the COVID-19
patients suffer from a lung infection similar to influenza.
So, it is possible to diagnose lung infection using imaging
techniques. Although a chest computed tomography
(CT) scan has been shown to be an effective imaging
technique for lung-related disease diagnosis, chest X-ray
is more widely available across the hospitals due to its
considerably lower cost and faster imaging time than CT
scan. The advancements in the area of machine learning
and pattern recognition has resulted in intelligent
systems that analyze CT Scans or X-ray images and
classify between pneumonia and normal patients. This
paper proposes KE Sieve Neural Network architecture,
which helps in the rapid diagnosis of COVID-19 using
chest X-ray images. This architecture is achieving an
accuracy of 98.07%. This noninvasive prediction method
can assist the doctors in this pandemic and reduce the
stress on health care systems.
Keywords— KE Sieve, Non-iterative Training, Image
Processing, Computer Vision, Pattern Recognition,
Machine Learning, COVID-19, X-ray Images.
The novel coronavirus (COVID-19), first appeared in
Wuhan, China in December 2019 and has been rapidly
spreading across the countries worldwide   and
subsequently threatening the health of billions of humans
and forcing millions of people to stay at home with the
majority of countries declaring lockdowns. It has been
declared as a pandemic by WHO . The rapid escalation
of COVID-19 virus with 2,397,216 confirmed cases and
162,956 confirmed deaths covering 213 countries, areas or
territories, (As on 21 April 2020, 2:00 AM CEST)  is
presenting a huge challenge to the governments across the
world, as new cases are being emerged and many new
hotspots are evolving on daily basis.
1 - ALPES.ai
2 - Department of Computer Science and Engineering, Sreenidhi Institute
Of Science and Technology
According to the World Health Organisation (WHO),
“COVID-19 is the infectious disease caused by the most
recently discovered coronavirus. This new virus and disease
were unknown before the outbreak began in Wuhan, China,
in December 2019.” . This COVID-19 is also called the
Severe Acute Respiratory Syndrome CoronaVirus 2
(SARS-CoV-2)  . Coronaviruses (CoV) belongs to a
family of viruses that cause colds such as the Severe Acute
Respiratory Syndrome (SARS-CoV) and the Middle East
Respiratory Syndrome (MERS-CoV). This COVID-19 virus
is new to human beings and has not been previously
identified in humankind. It is said that this virus outbreak is
due to the contamination of the virus from animals to
humans . According to studies,   the SARS-CoV
virus is contaminated from musk cats to humans, and the
MERS-CoV virus is contaminated from camels to
humans. But, the COVID-19 virus is presumed to be
contaminated from bats to humans . The COVID-19 virus
spreads primarily through droplets of saliva or through
cough and sneezing . This led to the transmission of the
virus from person to person and caused the rapid spread of
the epidemic and had become a pandemic. In this war
against COVID-19, all the countries have united together
and are fighting against the pandemic. But, this is never
about winning at this war, it is about survival. Survival of
mankind on earth.
The common symptoms of the disease include fever,
tiredness, dry cough. Other symptoms include, shortness of
breath, aches and pains, sore throat and very few people had
reported diarrhea, nausea, or a runny nose. 
The current diagnostic method for COVID-19 is
Real-Time Polymerase Chain Reaction (RT-PCR) which
uses viral nucleic acid detection in the blood sample.
However, there are a limited number of RT-PCR test kits
available in most of the countries. Therefore, it is necessary
to implement an automatic detection system as a quick
alternative diagnosis option to prevent COVID-19 spreading
among people.   
India, the second-most populous country in the world
with 1.2 billion people as of March 2011  and currently
has 18,601 confirmed cases and 590 deaths (As on 21 April
2020, 2:00 AM CEST).  Given the size of the
population these numbers may look small. But, it is a big
challenge to the government for the containment of the
spread of the disease. According to the Indian Council of
Medical Research (ICMR)  “A total of 4,01,586
samples from 3,83,985 individuals have been tested as on 19
April 2020, 9 PM IST. 17,615 individuals have been
confirmed positive among suspected cases and contacts of
known positive cases in India.” Are the number of positive
cases actually low or they are low because of low testing
rate still remains a question. There are many more such
countries with low testing rates . But it is essential to
increase the testing rate to curb the spread of COVID-19.
. Also, some of the eye-opening statistics of India are
that 67 percent of the Indian population resides in rural
areas and 90 percent of medical imaging facilities are in
cities, That makes only 10 percent of imaging facilities
spread across small towns in the country .
According to the World Health Organization, COVID-19
also opens holes in the lungs like SARS, giving them a
"honeycomb-like appearance"  . So, in this study,
we propose an AI-based pattern recognition system using
the KE Sieve Neural Network model   for the
detection of coronavirus infected patients, pneumonia and
healthy patients using chest X-ray radiographs. Also, there
are only 3 radiologists per 1,000,000 people in India .
So, an automatic screening system would not only help
India but also countries across the globe to do a rapid
screening and further prevent the spread of the virus. The
novelty of this paper is summarized as follows:
1. The proposed model has an end-to-end system
without manual human intervention .
2. Chest X-ray images are the best tool for the
detection of COVID-19.
3. The proposed model classifies between
COVID-19, Healthy, and Pneumonia patients.
4. With an increase in the number of training data in
the future on a day to day basis, the model can
learn as you go.
II. RELATED WORK
There are few studies on the emergence of COVID-19
virus disease. Fang et al.  analyzed computed
tomography (CT) scan images using deep neural networks
and reported a sensitivity of 98% using 51 COVID-19
patients. Also, Shi et al.  collected a large scale
COVID-19 CT dataset and developed a machine learning
model for COVID-19 screening. Ophir et al.  employed
deep learning models to detect COVID-19 on CT images.
Also, Prabira et al.  proposed the detection of
COVID-19 using X-ray images based on deep features and
SVM. They have extracted the deep features of CNN
models and fed them to the SVM classifier. They have
obtained 95.38% of accuracy for ResNet50 and Support
Vector Machine (SVM). Fei et al. , tried to predict
COVID-19 patients using “VB-Net” neural network to
segment COVID-19 infection regions in CT scans. They
obtained dice similarity coefficients of 91.6%±10.0%. Xu
et al. , proposed a classification model that classifies
COVID-19 from viral pneumonia and healthy cases using
pulmonary CT images using deep learning techniques.
Their CNN model has yielded the then highest overall
accuracy of 86.7 % on CT images. Shuai et al. , used
CT images to predict COVID-19 cases. They used the
inception transfer-learning model to establish the algorithm.
They obtained an accuracy of 89.5% with a specificity of
88.0% and a sensitivity of 87.0%.
In some analysis, the normal and pneumonia images have
been combined and a binary classification model between
COVID-19 and combined classes has been proposed, which
is not appropriate as the model will then try to ignore the
between-group variance amongst those two classes and the
accuracy thus obtained will not be a true measure. It is a
better approach to have a tri-class classification model.
The drawback of CT imaging is that typically it takes
considerably more time than X-ray imaging. Besides CT
scanners may not be available in many regions, making
timely COVID-19 screening impossible. In contrast,
X-rays are the most common and widely available
diagnostic imaging technique  and portable in nature.
Which makes it a better choice than CT imaging-based
detection of COVID-19.
III. PROPOSED MODEL
The KE Sieve Neural Network  [1b]  is applied to
the Datasets   while using features extracted from the
transfer learning of pre-trained model weights on the
VGG-19  CNN model.
The KE Sieve Algorithm  is a non-iterative and
adopts a new approach, which separates N data points of
n-dimension by at least one hyperplane. The number of
hyperplanes, qneeded approximately to separate N data
points is the order of q = log
(N)  provided N < 2nand
the computational complexity of this algorithm in Big - O
asymptotic notation is approximately,
(N) )+ ( n
where N is the data points and n is the dimension of space.
1. Consider a set of N train points in an n-dimensional
space. Assume this as 'G' space. Consider another
n-dimensional space as 'S', with no points in it. Draw some
initial planes in 'S' space, where the plane equation is
1 + 1 X 1 + 2 X 2 + 3 X 3 + ... + n X n = 0 (1)α α α α
2. To draw the initial planes, collect the random data
point pairs of size dimension (n) and substitute them in the
above equation (1).
3. Now, calculate the orientation vector (OV) for each point
with respect to all the planes in 'S' space and then transfer
one point at a time from 'G' space to 'S' space. This
Orientation vector gives information about whether the
point lies on the positive or negative side of the plane.
Figure 1: Process Flow Diagram
4. While transferring from 'G' space, OV is calculated and
placed in 'S' space for the first point. Then from the second
point onwards, OV is compared with OV of existing points
in 'S' space and if OV of the two points differs then the point
is placed. Which means the point is separated by plane. If
OV of two points matches then point is said to be in
the same ‘quadrant’  and the point is not placed. These
pairs of points are called neighbors and are collected
separately. This pair collection is repeated until it reaches
the size of dimension (n). Please refer to Figure 2 below for
a 2D representation of ‘S’ space.
5. Now, a new plane is drawn in 'S' space by passing
through the midpoints of each and every neighbor pair that
was collected above. This new single plane is sufficient to
separate all the neighbors in 'S' space.
6. Also, whenever a new plane is added, orientation vectors
(OV) of all the existing points in 'S' space are also updated
with respect to new hyperplane generated and this process is
continued until each and every training point is covered.
This ends the process of training the classifier.
7. Now, during predicting the label of a new test point, we
compute the dot product of the test point orientation vector
with all the train points orientation vectors. Take x% of the
maximum value of the dot product results and calculate the
Euclidean distance for those train points with the given test
point and assign the label of the training point with
minimum distance to the test point.
Figure 2: Representation of ‘S’ space point separation in 2D
This is the only algorithm  which has the advantage
of incremental learning. That is, if the new points are given
for training, the algorithm starts separating these points from
where it has previously stopped and OV gets updated
accordingly. There is no need to retrain the whole model.
The model uses two datasets  , which has been
combined to classify 3 classes as a whole. A total of 108
chest X-ray images of COVID-19 have been taken from this
dataset . The other two types of chest X-ray images
pneumonia and normal are taken from the Kaggle dataset
. Table I shows the distribution of the dataset across the
classes. Though the number of COVID-19 images available
is too small, it had no effect on the model as a whole as
transfer learning-based feature extraction is implemented
and SNN  mathematically could separate each data point.
Figure 3 shows the sample image of the dataset.
A B C
Figure 3: Sample chest X-ray images from the datasets. A - COVID-19; B -
Normal; C - Pneumonia
Table 1: Distribution of Dataset
We have used the 4,771 train images to train the KE
Sieve algorithm (as explained in the III-A Architecture
tested on the 1,193 test images. But, as the classifier expects
the inputs to be a real-valued vector, we have done few
pre-processing techniques like converting the image into the
standard size of 224 X 224 and have been fed into the
feature extractor of pre-trained VGG-19  based CNN
model. This represents the feature vector that the KE Sieve
algorithm can consume and separate the train points
distinctly. Principal Component Analysis is applied to the
feature vector and is plotted in 2 dimensions. Figure 4 below
showcases the 2D plot of the feature vector. When this
model is tested on the test points it resulted in a new state of
the art accuracy of 98.07%. Fig 1 explains the methodology
In this paper, the input is the image, and the output is the
predicted class label. The classification algorithm   is
implemented in the Python 3 programming language. The
environment is the local system with a processor of Intel®
Core™ i5-8250U CPU @ 1.60GHz × 8 and a RAM of 8 GB
running on Ubuntu OS with no use of GPU.
A. Evaluation Metrics
In this paper, the primary metric is accuracy for model
evaluation. Other metrics like the sensitivity and specificity
are also evaluated for the model. The metrics are measured
using the confusion matrix (Fig 2). Metrics are defined as,
Accuracy = (TP + TN)
(TP + FP + FN + TN)
Sensitivity = TP / (TP+FN)
Specificity = TN / (TN+FP)
- Score = (2 * TP) / ((2 *TP) + FP + FN)
Where, T - True, F - False, P - Positive, N - Negative.
The whole model was rebuilt 10 times, as this helps to
keep a check on random initializations.
Fig 3: Confusion Matrix
With the KE Sieve classification approach  we just
need 18 planes to separate all the train data points in just ~2
seconds. This resulted in an accuracy of 98.07% and
sensitivity of 100% and specificity of 100% which is greater
than other current models. The other metrics of the model
are shown in Table II. From the confusion matrix it is
observed that there has been misclassification between
Normal and Pneumonia classes. We hope the balanced
dataset may overcome this scenario.
F1 - Score
Table -II: Metrics Report
The model is built on limited data of COVID-19 is
because the disease is new and datasets are not yet available.
But we are convinced that with more data also, these results
will hold and surely a large number of images would
contribute to improving the model, because of the nature of
the SNN algorithm . From our experience with KE SNN
, the more the data points the better the model is as more
planes are drawn to separate the data points.
Figure 4: 2D Representation of Feature Vectors
C. Comparative Study
Our proposed model shows that the classification
performance on the dataset   is improved and this
resulted in higher accuracy when compared with the results
of others mentioned in Section II - Related Work.
The contribution of this paper is showcasing the
effectiveness of this end to end classification model and
chest X-ray images are the best tool for the detection of
COVID-19 and the proposed model classifies between
COVID-19, Healthy, and Pneumonia patients. This model
has been deployed as an application  and anyone can
test it by uploading the X-ray image of the chest.
In our future work, we will explore better ways in
feature extraction and classification and also try for the
balanced dataset, to ensure the model is not over-fitted or
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