GODAVARI INSTITUTE OF
ENGINNERING AND
         TECHNOLOGY
    DEPARTMENT OF COMPUTER SCIENCE AND
               ENGINEERING
                A PAPER PRESENTION ON
        IMAGE PROCESSING
                             BY
P.S.D ALEKHYA                          G.V.ALEKHYA
4/4CSE                                  4/4 CSE
                alekhya.pinninti@gmail.com
                                  techniques that can
                                  identify shades,
                                  colors and
                                  relationships that
                                  cannot be perceived
                                  by the human eye.
ABSTRACT
        Image processing is       2. Any image
a technique to enhance            improvement, such as
raw images received from          refining a picture in a
cameras/sensors placed            paint program that
on satellites, space probes       has been scanned or
and aircrafts or pictures         entered from a video
taken in normal day-to-           source.
day life in various               3. A set of
applications. The data        computational techniques
from an image is              for analyzing, enhancing,
digitized and various         compressing, and
mathematical operations       reconstructing images
are applied to the data,         4. Used to solve
generally with a digital      identification
computer, in order to         problems, such as in
create an enhanced image      forensic medicine or in
that is more useful or        creating weather maps
pleasing to a human           from satellite pictures. It
observer, or to perform       deals with images in
some of the interpretation    bitmapped graphics
recognition tasks usually     format that have been
performed by humans..         scanned in or captured
                              with digital camera.
It is
                                      Various
    1. The analysis of a
                              techniques have been
         picture using
developed in image                May remove
processing during the last          noise,
                                  Improve the
four to five decades.
                                    contrast of the
Most of the techniques              image,
are developed for                 Remove blurring
                                    caused by
enhancing images                    movement of the
obtained from unmanned              camera during
                                    image acquisition
aircrafts, space probes         It may correct for
and military                 geometric
reconnaissance flights.      A few decades ago,
Image processing systems     image processing was
are becoming popular due     done largely in the analog
to easy availability of      domain, chiefly by
powerful personal            optical devices. Analog
computers, large size        image processing refers
memory devices, graphic      to the alteration of image
software’s etc               through electrical means.
                             These optical methods
INTRODUCTION
Image processing is in       are still essential to
many cases concerned         applications such as
with taking one array of
pixels as input and          holography because they
producing another array      are inherently parallel;
of pixels as output, which
in some way represents       however, due to the
an improvement to the        significant increase in
original array. Most
image processing             computer speed, these
techniques involve           techniques are
treating the image as a
two-dimensional signal       increasingly being
and applying standard        replaced by digital image
signal processing
techniques to it.            processing methods.
For example, this
processing                   Digital image processing
                             techniques are generally
more versatile, reliable,        Resolution
and accurate; they have
                                 Dynamic range
the additional benefit of
being easier to implement        Bandwidth
than their analog                Filtering
counterparts. Digital            Differential
computers are used to             operators
process the image. The
                                 Edge detection
image will be converted
to digital form using a          Domain
digitizer and then process        modulation.
it. Today, hardware
solutions are commonly        Two-dimensional
used in video processing     techniques
systems. However,                  Image
commercial image                      representation
processing tasks are more          Image
commonly done by                      preprocessing
software running on
                                   Image
conventional personal
                                      enhancement
computers.
                                   Image restoration
Commonly used signal               Image analysis
processing techniques:             Image
Most of the signal                    reconstruction
processing concepts that           Image data
apply to one-dimensional
                                      compression
signals also extend to the
                             Image Reresentation :
two-dimensional image
                             image defined in the to
signal. Some of these
                             be a function of two real
one-dimensional signal
                             variables, for example, f
processing concepts
                             (x, y) with f as he
become significantly
                             amplitude (e.g.
more complicated in two-
                             brightness) of the image
dimensional processing.
                             at the real coordinate
Image
                             position (x, y).
processing brings some
new concepts, such as
connectivity and
rotational invariance that
are meaningful only for
two-dimensional signals.
One-dimensional
techniques
                                Image resolution can be
  The 2D continuous             measured in various
image f (x, y) is divided       ways. Basically,
into N rows and M               resolution quantifies how
columns. The intersection       close lines can be to each
of a row and a column is        other and still be visibly
called s pixel. The value       resolved. Resolution units
assigned to the integer         can be tied to physical
coordinates [m, n] with         sizes (e.g. lines per mm,
{m=0,1,2,.........M-1} and      lines per inch) or to the
{n=0,1,2,.............N-1} is   overall size of a picture
f {m, n}. In fact in most       (lines per picture height,
cases f (x, y) -- we might      also known simply as
consider to be the              lines, or TV lines).
physical signal that            Furthermore, line pairs
impinges on the face of         are often used instead of
the sensor. Typically an        lines. A line pair is a pair
image file such as BMP,         of adjacent dark and light
JPEG, TIFF etc., has            lines, while lines count
some picture and header         both dark lines and light
information. A header           lines. A resolution of 10
usually includes details        lines per mm means 5
like format identifier          dark lines alternating
(typically first                with 5 light lines, or 5
information), resolution,       line pairs per mm.
number of bits/pixel,           Photographic lens and
compression type etc.           film resolution are most
                                often quoted in line pairs
                                per mm.
Image resolution
Image resolution
describes the detail an         Scaling:
image holds. The term
applies equally to digital
images, film images, and
other types of images.
Higher resolution means
more image detail. It is
illustrated by following
image.
Scaling is defined as the    row, mth column of the
      increase or            original imagery is
      reduction of image     selected and displayed.
      size by a fixed        Another way of
      ratio. The theme of    accomplishing the same
      the technique of       is by taking the average
      magnification is to    in ‘m x m’ block and
      have a closer view     displaying this average
      by magnifying or       after proper rounding of
      zooming the            the resultant value.
      interested part in
      the imagery. By
      reduction, we can
      bring the
      unmanageable size
      of data to a
      manageable limit.
      Image
      Preprocessing
1. Magnification
   This is usually done to
improve the scale of
display for visual             2-dimensional image
interpretation or                    scaling
sometimes to match the
scale of one image to        In the above signal, the
other. To magnify an         image is magnified
image by a factor 2, each    vertically and reduced
pixel of the original        horizontally.
image is replaced by         Rotation
block of 2 x 2 pixels, all     Image rotation is
with the same brightness     performed by computing
value as the original        the inverse
pixel.                       transformation for every
                             destination pixel.
2. Reduction                 Rotation is used in image
Image reduction increases    mosaic, image
the incidence of high        registration etc. One of
frequencies and causes       the techniques of rotation
several pixels to collapse   is 3-pass shear rotation,
into one. To reduce a        where rotation matrix can
digital image of the         be decomposed into three
original data, every mth     separable matrices.
    Image rotation
                         Image mosaicking
                      Image enhancement:
Mosaic                 Image enhancement is
                     the improvement of
                     digital image quality,
                     without knowledge about
                     the source of degradation.
                     In Image enhancement,
                     the goal is to accentuate
                     certain image features for
                     subsequent analysis or for
image display. If the
source of degradation is
known, one calls the
process image
restoration. Both are
iconical processes, viz.
input and output are
images. It is quite
easy, for example, to
make an image lighter or
darker, or to increase or
decrease contrast, pseudo
colouring, noise filtering,
sharpening and
magnifying. Advanced               Image
image enhancement
software also supports
                                enhancement
many filters for altering
images in various ways.       An image is enhanced
Programs specialized for      when it is modified so
image enhancements are        that the information it
sometimes called image        contains is more clearly
editors.                      evident, but enhancement
                              can also include making
The aim of image              the image more visually
enhancement is to             appealing. An example is
improve the                   noise smoothing.
interpretability or           Another example of
perception of information     enhancement is contrast
in images for human           manipulation, where each
viewers or to provide         pixel's value in the new
`better' input for other      image depends solely on
automated image               that pixel's value in the
processing techniques. It     old image; in other
is illustrated as follows:    words, this is a point
                              operation. Contrast
                              manipulation is
                              commonly performed by
                              adjusting the brightness
                              and contrast
                              Image noise reduction:
                              Images taken with both
                              digital cameras and
                              conventional film
                              cameras will pick up
                              noise from a variety of
                              (partially) removed - for
aesthetic purposes as in       compensate for the
artistic work or               degradation it caused.
marketing, or for              The most common
practical purposes such as     degradations have their
computer vision                origin in imperfections of
                               the sensors, or in
Noise filtering is used to     transmission.
filter the unnecessary
information from an
image. It is also used to
remove various types of
noises from the images.
     Noise reduction
Image restoration:
Images typically suffer
from a range of
imperfections including
geometric distortion, non-
uniform contrast, and
noise. Image restoration           Image restoration
removes or minimizes
some known degradations        The aim of restoration is
in an image. It can be         also to improve the
seen as a special kind of      image, but unlike
image enhancement.             enhancement, knowledge
Image restoration is to        of how the image was
"compensate for" or            formed is used in an
"undo" defects, which          attempt to retrieve the
degrade an image.              ideal (uncorrupted)
Degradation comes in           image. Any image-
many forms such as             forming system is not
motion blur, noise, and        perfect, and will
camera misfocus. In cases      introduce artifacts (for
like motion blur, it is        example, blurring,
possible to come up with       aberrations) into the final
a very good estimate of        image that would not be
the actual blurring            present in an ideal image.
function and "undo" the        A point-spread function,
blur to restore the original   called a filter, can be
image. In cases where the      constructed that undoes
image is corrupted by          the blurring. By imaging
noise, the best we may         the blurred image with
hope to do is to               the filter point spread
                               function, the restored
                               image results. The filter
point spread function is     systems measure
spread out more than the     quantitative information
blurring point spread        and use it to make a
function, bringing more      sophisticated decision,
pixels into the averaging    such as controlling the
process. This is an          arm of a robot to move an
example of a global          object after identifying i
operation, since perhaps     or navigating an aircraft
all of the pixels of the     with he aid of images
blurred image can            acquired along its
contribute to the value of   trajectory.
a single pixel in the
restored image. This type    Image Reconstruction:
of deblurring is called       Image reconstruction is a
inverse filtering, and is    special class of image
sensitive to the presence    restoration, where a two-
of noise in the blurred      dimensional object is
image. By modifying the      reconstructed from
deblurring filter            several One-dimensional
according to the             projections. Each
properties of the noise,     projection is obtained by
performance can be           projecting a parallel X-
improved. An example of      ray (or other penetrating
the need to deblur images    radiation) beam through
from an optical system is    the object. Planar
the Hubble Space             projections are thus
Telescope before its         obtained by viewing the
spherical aberration was     object from many
corrected with new           different angles.
optics.                      Reconstruction
Image Analysis:              algorithms derive an
 Image analysis is           image of a thin axial slice
concerned with making        of the object, giving an
quantitative                 inside view otherwise
measurements from an         unobtainable without
image to produce a           performing extensive
description of it. In the    surgery. Such techniques
simplest form, this ask      are important in medical
could be reading a label     imaging (ct scanners)
on a grocery item, sorting   astronomy, radar
different pars on an         imaging, geological
assembly line, or            exploration, and non-
measuring he size ad         destructive testing of
orientation of blood cells   assemblies.
in medical image. More
advanced image analysis      Image Compression:
Image Compression              as three to four may be
(often known as Image          acceptable.
Coding) is the art /
science of representing
images with the least
information (no. of bits)
consistent with achieving
an acceptable image
quality / usefulness.
Compression is a way of
representing an image by
fewer numbers, at the
same time minimizing the
degradation of the
information contained in
the image. Compression
is important because of
the large quantities of
digital imagery that are
sent electronically and
stored. Digital high-
definition television relies
heavily on image
compression to enable             Image compression
transmission and display
of large-format color          Image compression can
images. Once the image         be lossy or lossless.
is compressed for storage      Lossless compression is
or transmission, it must       sometimes preferred for
be uncompressed for use,       artificial images such as
by the inverse of the          technical drawings, icons
compression operations.        or comics. This is
There is a trade-off           because lossy
between the amount of          compression methods,
compression and the            especially when used at
quality of the                 low bit rates, introduce
uncompressed image.            compression artifacts.
High compression rates         Lossless compression
are acceptable with            methods may also be
television images, for         preferred for high value
example. However,              content, such as medical
where high image quality       imagery or image scans
must be preserved (as in       made for archival
diagnostic medical             purposes. Lossy methods
images), only                  are especially suitable for
compression rates as low       natural images such as
photos in applications       term that covers the use
where minor (sometimes       of digital image
imperceptible) loss of       processing techniques to
fidelity is acceptable to    process, analyze and
achieve a substantial        present images obtained
reduction in bit rate.       from a microscope.
 The best image quality at
a given bit-rate (or         Medical imaging:
compression rate) is the     Medical imaging
main goal of image           designates the ensemble
compression.                 of techniques and
                             processes used to create
APPLICATIONS:                images of the human
   Photography and          body for clinical purposes
     printing                or medical science.
   Satellite image
                             Morphing:
     processing
                             Morphing is a special
   Medical image            affect in motion pictures
     processing              and animations that
   Face detection,          changes (or morphs) one
     feature detection,      image into another
     face identification     through a seamless
   Microscope image         transition. Most often it is
     processing              used to depict one person
                             turning into another
   Car barrier
                             through some magical or
     detection
                             technological means.
   Morphological
     image processing
Face detection:
Face detection is a
computer technology that
determines the locations
and sizes of human faces
in arbitrary (digital)               Morphing
images. It detects facial
features and ignores
anything else, such as
buildings, trees and
bodies.                      RESEARCH:
                             Image processing is an
Microscope image             active area of research in
processing:                  such diverse fields as
Microscope image             medicine, astronomy,
processing is a broad
microscopy, seismology,       turnaround, easing of
defense, industrial quality   growing workload, etc...
control, and the              By embracing the new
publication and               image processing
entertainment industries.     technologies and further
The concept of an image       refinements in image
has expanded to include       processing techniques,
three-dimensional data        users are likely to find it
sets (volume images), and     more beneficial, not less,
even four-dimensional         in future, while more
volume-time data sets.        refinements in image
An example of the latter      processing techniques
is a volume image of a        will be appreciated at a
beating heart, obtainable     reduced cost. Overall,
with x-ray computed           Image processing is a
tomography (CT),              good option that deserves
ultrasound, confocal          a careful look.
microscopy, scanning
tunneling microscopy,         RESULT:
atomic force microscopy,
and other modalities have     In recent years there were
been developed to             many improvements in
provide digitized images      the areas of image
directly. Digital images      processing, more
are widely available from     specifically, the areas of
the Internet, CD-ROMs,        block artifact and
and inexpensive charge-       mosquito noise
coupled-device (CCD)          reduction... Other typical
cameras, scanners, and        areas of image processing
frame grabbers. Software      improvements include
for manipulating images       adaptive contrast
is also widely available.     enhancement, sharpness
                              and texture enhancement,
CONCLUSION:                   and selective color
We all know that new          correction. The latest
technologies, at first        advancements also
perceived as unwelcome,       resulted in the
subjected to some             compression rate in
modifications, usually        recent years there were
lead to better, more          many improvements in
productive situations for     the areas of image
everyone. In the case of      processing, more
image processing, the         specifically, the areas of
potential benefits are        block artefact and
many: refined images can      mosquito noise
be obtained, faster report    reduction... Other typical
areas of image processing
improvements include
adaptive contrast
enhancement, sharpness
and texture enhancement,
and selective colour
correction. The latest
advancements also             References: -
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