Image analysis using wavelets part.1

IMAGE IMAGE ANALYSIS USING ANALYSIS USING

WAVELETSWAVELETS

PARTPART--1 : Fundamentals of Image 1 : Fundamentals of Image ProcessingProcessing

PARTPART--2 2 : Wavelets: Wavelets

Presentation on……..Presentation on……..

PARTPART--2 2 : Wavelets: Wavelets

By

Prof.B.B.S.KUMARProf.B.B.S.KUMARResearch Scholar, Assistant Professor,Research Scholar, Assistant Professor,

RajarajeswariRajarajeswari College of Engineering,College of Engineering,

Bangalore, IndiaBangalore, India

1FDP Lecture-1, Dept. of ECE, RRCE,

Bangalore, India

PARTPART--1 1 : Fundamentals of Image : Fundamentals of Image

ProcessingProcessingProcessingProcessing

FDP Lecture-1, Dept. of ECE, RRCE,

Bangalore, India2

PRESENTATION OUTLINEPRESENTATION OUTLINE

•• What is Image?What is Image?

•• What What is Digital Image Processing?is Digital Image Processing?

•• Sampling and ReconstructionSampling and Reconstruction

•• Color Image ProcessingColor Image Processing

•• The Origins of Digital Image ProcessingThe Origins of Digital Image Processing

•• Fundamental Steps in Digital Image Fundamental Steps in Digital Image

ProcessingProcessing

•• Components of an Image Processing SystemComponents of an Image Processing System


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One picture is worth more than ten thousand words


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WHAT IS IMAGEWHAT IS IMAGE??

• Image is physical quantity

• Converted into electrical signal by transducers

• Consist of an Data and mathematical function

and represented in 1-D signal

• Using 1-D signal processing is called signal • Using 1-D signal processing is called signal

processing


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What is Digital Image Processing?What is Digital Image Processing?

• Electrical Signal is Sampled, Quantized and Encoded –

DSP

• Image Signal is Sampled, Quantized and Encoded – DIP

Digital Image Processing

• f(x,y): A 2-dimensional function, where x and y are

spatial(plane) coordinates, and the amplitude of f at any

pair of coordinates (x,y) is called the intensity or gray

level of the image at that point called a digital image.


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• x size: 512, y size : 512, gray levels: 256

Gray scale image : 262KB, Color image : 786KB

• Digital image: x, y, and the amplitude values of f are

all finite, discrete quantities

• Image Mathematical representation in Matrix form m

x n, m as rows and n as columns x n, m as rows and n as columns

• Digital image is composed of a finite number of

elements, these elements are called picture elements,

image elements, pels and pixels

• A pixel is a sample of a continuous function8


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Image Formats

• TIFF -Tagged Image File Format (.tiff., tif)

• JPEG -Joint Photographic Experts Group

(.jpg., jpeg)

• GIF -Graphics Interchange Format (.gif)

• BMP -Windows Bitmap (.bmp)• BMP -Windows Bitmap (.bmp)

• PNG -Portable Network Graphics (.png)

• XWD -X Window Dump (.xwd)


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Properties of Images

• Spatial resolution

Width pixels/width cm and height pixels/ height cm

• Intensity resolution

Intensity bits/intensity range (per channel)Intensity bits/intensity range (per channel)

• Number of channels

RGB is 3 channels, grayscale is one channel


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Electromagnetic Spectrum


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Image Errors• Spatial Aliasing

Not enough spatial resolution

• Intensity Quantization

Not enough intensity resolution

Two Issues• Sampling and Reconstruction• Sampling and Reconstruction

Creating and displaying images while reducing spatial aliasing

errors

• Halftoning Techniques

Dealing with intensity quantization


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Aliasing• Artifacts caused by too low sampling frequency

(undersampling) or improper reconstruction

• Undersampling rate determined by Nyquist limit (Shannon’s sampling theorem)

Aliasing in computer graphicsIn graphics, two major typesIn graphics, two major types

• Spatial aliasing

Problems in individual images

• Temporal aliasing

Problems in image sequences (motion)


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SAMPLING AND RECONSTRUCTIONSAMPLING AND RECONSTRUCTION


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Color Image ProcessingColor Image Processing

Color Image Processing divided into two major

areas:

– Full color(Sensor, color TV camera and color scanner)

– Pseudocolor(color to particular monochrome intensity

or range of intensities)or range of intensities)

Quality of a chromatic light source:

– Radiance(energy(Watts) flows from the light source),

– Luminance(measure of energy(lumens) source)

– Brightness(impossible to measure)


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• Human eye absorption

– Primary colors-Red, Green and Blue(RGB)

– Wavelength:R-700nm, G-346.1nm, B-435.8nm

• Primary colors can be produce the secondary colors of light

– Magenta(R+B), Cyan(G+B) and Yellow(R+G)

Contd……

– Magenta(R+B), Cyan(G+B) and Yellow(R+G)

• Digital technologies

– CRT(Cathode Ray Tube),

– LCD(Liquid Crystal Displays) ,

– TFTs(Thin Film transistors)

– Plasma Devices


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Color Models(color space or color system)Color Models(color space or color system)

– RGB(Red, Green and Blue)

– CMY(Cyan, Magenta and Yellow)

– CMYK(Cyan, Magenta, Yellow and Black)

– HIS(Hue, Saturation and Intensity)

– Red, Green and Blue- each 8-bit image– Red, Green and Blue- each 8-bit image

– RGB color pixel-24 bits

– The total number of colors in a 24-RGB image is (28)3=16,777,216

– 24-bit RGB image are limited to 256 colors

– 216 common colors are used.

– 40 colors unknown.17


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The Origins of Digital Image The Origins of Digital Image


• One of the first applications of digital images

was in the newspaper industry, when pictures

were first sent by submarine cable between

London and New York.London and New York.


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Better

Quality


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1515--Tone Tone

EquipmentEquipment


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From computers, meaningful image processing From computers, meaningful image processing

tasks appearedtasks appeared


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Electromagnetic Energy Spectrum


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Gamma-

Ray

Imaging


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X-ray

Imaging


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Imaging in Imaging in

the

Ultraviolet

Band


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Imaging Imaging

in the

Visible

and

Infrared

Bands


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Remote sensing


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Weather Weather Observation, visible and infraredbands


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Infrared Infrared

Imaging


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Automated

Visual

Inspection


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Imaging in Imaging in

the

Microwave

Band


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Imaging

in the

Radio

Band

MRI


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SoundSound

Examples in which Other Imaging Modalities Are Used

SoundSound


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UltrasoundUltrasound


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Electron

MicroscopeMicroscope


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Images Images

generated generated generated generated

by by

computerscomputers


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Fundamental Steps in Digital Image Fundamental Steps in Digital Image



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Computerized Processes– Low level Processes

– Mid Level Processes

– Higher level Processes

• Low Level Processes– Image preprocessing-reduce noise, contrast enhancement and image

sharpening- inputs and outputs are images

• Mid Level Processes• Mid Level Processes– Segmentation(partitioning an image into regions or objects)

– Inputs are images

– Outputs are attritubes extracted from those images(edges, contours, and the identity of individual objects)

• Higher level Processes– Making sense of recognozied objects with human vision– Human vision perception is very important


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Components of an Image Processing

System


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To be continued…………Next

PARTPART--2:Wavelets2:Wavelets


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THANK YOU!THANK YOU!


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