Lecture 1 Introduction Objectives Digital image processing, Why? - - PowerPoint PPT Presentation

Lecture 1

Introduction

Objectives

• Digital image processing, Why?
• Scope of digital image processing
• Exploration of application areas
• Components in a typical general-purpose image

processing system

• Directions

Digital image processing application areas

• Improving of pictorial information for human

interpretation

• Processing of image data for

– Storage – Transmission – Representation for autonomous machine perception

Computer Vision: Input: Images Output: Knowledge of the scene (recognize objects, people, activity happening there, distance of the object from camera and each other, ...) Methods: Uses image processing, machine learning, ... Image Processing: Input: Images Output: Images (Might be in different formats, for example compressed images). No knowledge of the scene is given.

Why digital image processing?

Image=> f(x,y), where x and y are spatial coordinates, f is the intensity When x, y, and f ate all finite, discrete quantities => digital image Digital image processed by computer=> digital image processing

Each element is called: picture element, image element, pel, and pixel

Machines can see what human could not see!

Machines cover almost the entire EM spectrum Machine can associate ultra-sound to images Machine can generate images (not only see existing images)

Images based on radiation from the EM spectrum are the most familiar, especially the images in X-ray and visual bands of the spetrum. Electromagnetic waves are a stream of massless particles, each traveling in a wave like pattern and moving at the speed of light.Each massless particle contains a bundle (certain amount) of energy that is called a photon.

Image processing and other areas

Image processing Image analysis and Computer vision (recognition, learning, inferences, take decisions)

Low-level processing (image=>image) (reduce noise, contrast enhancement, …)

• Ex. acquiring and

preparing an image of a piece of text Mid-level processing (segmentation, description

• f isolated objects, …)
• Ex. Segmenting individual

letters, extracting attributes from letter image, recognizing letters Height-level processing (making sense, cognitive

• peration, …)
• Ex. Making sense about the

piece of text, making decision based on its contents, understanding the contents

Origin of digital image processing

1920: Bartlane cable transmission system reduced the time required to transport an image across the Atlantic from more than a week to less than three hours (digitizing, transmission, reproduction)

5 distinct levels of gray 15 distinct levels of gray

Transmission on submarine cables of images for newspaper industry between London and New York 5 distinct levels of gray with photographic reproduction for printing at the receiving end

Origin of digital image processing

Correcting various types of image distortion inherent in the on-board television camera on spacecraft are first digital image processing operations where digital computers were used in performing them

Early application of DIP

Computerized axial tomography(CAT or CT): early 1970s 1960-1970: using digital image processing in medicine and, remote earth resources

• bservations and astronomy

Computer procedures are used to enhance the contrast or code the intensity levels into color for easier interpretation of X-rays and

• ther images used in industry,

medicine, and the biological

• sciences. Examples are images for

Pollution patterns, earth layers and contents

Energy source (EM, ultrasonic, acoustics, electronic,…)

• bject

Sensing

Passing through or reflected from the object

Generated Synthetic, modeling, visualization

Image sources

Produced by energy source

Gamma-Ray imaging

Examples of gamma-ray imaging: (a) Bone scan (b) positron emission tomography (PET) image (c) Cygnus Loop (d) Gamma radiation (bright spot) from a reactor valve.

(a) Chest X-ray (b) Aortic angiogram (Image of blood vessels using catheter) (c) Head CAT(Computerized axial tomography). (d) Circuit boards (check missing/broken parts) (e) Cygnus Loop. Examples of X-ray imaging

Imagining in the Ultraviolet Band

Examples of ultraviolet imaging. (a) Normal corn. (b) Smut corn (sick). (c) CygnusLoop. The ultraviolet light itself is not visible, but when a photon

• f ultraviolet radiation collides with an electron in an

atom of a fluorescent material, it elevates the electron to a higher energy level. Subsequently, the excited electron relaxes to a lower level and emits light in the form of a lower-energy photon in the visible (red) light region.

Imaging in the visible/infrared band

Examples of light microscopy images: (a) Taxol (anticancer agent), magnified 250X. (b) Cholesterol 40X. (c) Microprocessor 60X. (d) Nickel oxide thin film 600 X. (e) Surface of audio CD 1750 X. (f) Organic superconductor 450 X.

Imaging in the visible/infrared band

Remote sensing bands

Imaging in the visible/infrared band

LANDSAT satellite images of the Washington, D.C. area. The numbers refer to the thematic bands in the preceding Table 1.1.

Weather observation and prediction are major applications of multispectral imaging from satellites For example, The shown figure is an image of a hurricane taken by a satellite using sensors in the visible and infrared bands. The eye of the hurricane is clearly visible.

Imaging in the visible/infrared band

ternado ternado

This image is a part of the Nighttime Lights of the World data set, which provides a global inventory of human settlements. The images were generated by the infrared imaging system mounted on a NOAA DMSP (Defense Meteorological Satellite Program) satellite. The infrared imaging system operates in the band 10.0 to 13.4 micro-meter, and has the unique capability to observe faint sources of visible near infrared emissions present on the Earth's surface, including cities, towns, villages, gas flares, and fires.

Imaging in the visible/infrared band

Imaging in the visible/infrared band

Imaging in the visible/infrared band

Automated visual inspection of manufactured goods. (a) Is a controller board for a CD-ROM drive. (the black square on the top, right quadrant of the image is a missing component). (b) Is an imaged pill container. The objective here is to have a machine look for missing pills. (c) An application in which image processing is used to look for bottles that are not filled up to an acceptable level. (d) Bubbles in clear-plastic product.

(a) Thumb print. (b) Paper currency (c) And (d). Automated license plate reading.

Additional examples of imaging in the visual spectrum.

Imaging in the Microwave Band

dominant application : radar. A radar emits it’s own microwave pulses and receive the returned microwave through antenna. Computer processing is used to make useful images Unique feature : Its ability to collect data

• ver virtually any region at any time,

regardless of weather or ambient lighting conditions.

Radar image of mountains in southeast Tibet.

Imaging in the Radio Band

In medicine radio waves are used in magnetic resonance imaging (MRI).

Report discussion

Last lecture report: None New report: : By searching the internet and other resources, give three application of digital image processing with sufficient explanation

Other imaging modalities

Imaging using "sound" finds application in geological exploration, industry, and medicine. Ex: Mineral and oil exploration. Over land, one

• f the main approaches is to use a large truck

and a large flat steel plate. The plate is pressed

• n the ground by the truck, and the truck is
• vibrated. The strength and speed of the

returning sound waves are determined by the composition of the earth below the surface. These are analyzed by computer, and images are generated from the resulting analysis. If the sound wave source move ,like a ship, A 3D model id constructed

The figure shows a cross-sectional image

• f a well-known 3-D model. The arrow

points to a hydrocarbon (oil and/or gas)

• trap. This target is brighter than the

surrounding layers because of the change in density in the target region is larger.

Ultrasound imaging

1. The ultrasound system (a computer, ultrasound probe consisting of a source and receiver, and a display) transmits high-frequency 2-5 MHz) sound pulses into the body. 2. The sound waves travel into the body and hit a boundary between tissues (e.g., between fluid and soft tissue, soft tissue and bone). Some of the sound waves are reflected back to the probe, while some travel on further until they reach another boundary and get reflected. 3. The reflected waves are picked up by the probe and relayed to the computer. 4. The machine calculates the distance from the probe to the tissue or

• rgan boundaries using the speed of sound in tissue A540 m/s) and

the time of the each echo's return. 5. The system displays the distances and intensities of the echoes on the screen, forming a two-dimensional image.

A stream of electrons is produced by an electron source and accelerated toward the specimen. This stream is confined and focused using metal apertures and magnetic lenses into a thin, focused, monochromatic beam. This beam is focused onto the sample using a magnetic lens. Interactions occur inside the irradiated sample, affecting the electron beam. These interactions and effects are detected and transformed into an image, much in the same way that light is reflected from, or absorbed by, objects in a scene.

Imaging using Electron microscopes

(a) 250X SEM image of a tungsten filament following thermal failure. (b) 2500X SEM image of damaged integrated circuit. (TEM) transmission electron microscope (slide projector) (SEM),A scanning electron microscope(TV raster scan)

Generated Images

(a) and (b) Fractal (pattern repetition) images (c) and (d) Images generated from 3-D computer models of the objects shown.

Fundamental steps in digital image processing.

Components of an Image processing System