Digital Image Processing Introduction
-
Upload
ashish-kumar -
Category
Documents
-
view
54 -
download
5
description
Transcript of Digital Image Processing Introduction
DIGITAL IMAGE PROCESSING
Introduction
What is DIP and DI It is use of the computer algorithms to perform image
processing on digital images. An image is a 2-D light intensity function f(x,y). A digital image is a numeric representation of 2-D image also called bitmap image. Digital image is composed of a finite number of elements each of which has a particular location and value these elements are called pixels. Digital image contains a fixed number of rows and columns of pixels. Pixels are smallest indivisual element in an image holding quantized values that represent the brightness of a given color at any specific point.
Image Representation
Image Representation
Image Representation
In 8-bit representation pixel intensity values change
between 0(black) and 255(white). An image may also be defined as a two-dimensonal function,f(x,y),where x and y spatial(plane ) coordinates,and the amplitude of f at any pair of coordinates(x,y) is called the intensity of the image at that point. The term gray level is used often to refer to the intensity of monochronous images. In image processing we use the entire EM spectrum ,ranging from gamma to radio waves. So it has wide range of variety. Two things are important image processing and image analysis.
Why do we need image processing? One of the first application of digital image was in
the newspaper industry ,when pictures were first sent by submarine cable between london and new york. This techniques reduced the time from 6 days to 3 hour. So basically image processing reduces the time in many areas. There are three major category 1) For improvement of pictorial information for human perception. 2)Image processing for autonomous machine
Human Perception We employ methods capable of enhancing
pictorial information for human interpretation and analysis. Applications : Noise filtering, content enhancement ( contrast enhancement,deblurring ) ,remote sensing Through remote sensing we can plan the city,finding the path of the river. E.g. borneo fire (fire in forest ),atmospheric study,astronomy. Other fields are medical imging (brain tumor),cancer detection,ultra sonogram. In weather forecasting we can use the image
Blurred image
Low contrast image
Medical Imaging (Brain Tumor)
Remote Sensing
Noisy image
Machine vision Applications Extracting the features of image not enhancing
like in human perception. Industrial machine vision for product assembly and inspection. E.g bottling process Inspection of process of IC manufacturing. Automated target detection and tracking Finger print recognition,iris recognition Machine processing of aerial and satellite imagery for weather prediction and crop assessment etc.
Borneo fire
Aerial image of path of river
Automated Inspection
Bottling Production
Automated Inspection
Medical Imaging
Weather Forecasting
Astronomy
Finger Pattern
Examples of fields Gamma ray imaging. It includes nuclear medicine
and astronomical observations. In nuclear medicine the approach is to inject a patient with a radioactive isotope that exists gamma rays as it decays.images are produced from the emissions collected by gamma ray detectors.
Image Compression An image usually contains lot of redundancy that
can be exploited to achieve compression. Reduction in bandwidth and storage.
Steps in digital image processing Problem domain
Image aquisition Preprocessing segmentation
Knowledge Representation and description Base Recognition and interpretation Result
Relationship between pixels Connection between pixels is important for finding
the components. We know that digital image is represented as matrix format. A pixel p at location (x,y) has two horizontal and two vertical neighbors. This set of four pixels is called 4-neighbors . Each of these neighbors is at a unit distance from p. If p is a boundary pixel then it will have less number of neighbors. E.g. for finding the circle.
Gray Iris image
Skeleton of iris image
A pixel p has four diagonal neighbors.
4-neighbors and diagonal neighbors are called 8-
neighbors of p. Connectivity between pixels is a very important concept. It is useful for establishing object boundaries and defining image components and regions. E.g. segmentation of image from background
Two pixels are said to be connected if they are
adjacent in some sense. They are neighbors and their intensity values are similar. Distance between pixels. Logical and mathematical operation on image.
Matlab (Image processing toolbox) Imread
Size Whos Figure Imfinfo Rgb2gray Edge