S. Mandayam/ DIP/ECE Dept./Rowan University

Digital Image ProcessingDigital Image Processing

0909.452.01/0909.552.010909.452.01/0909.552.01 Fall 2001Fall 2001

Shreekanth MandayamECE Department

Rowan University

http://engineering.rowan.edu/~shreek/fall01/dip/

Lecture 13Lecture 13December 10, 2001December 10, 2001

S. Mandayam/ DIP/ECE Dept./Rowan University

PlanPlan• Course Review

• Final Project Presentations

• Lab

S. Mandayam/ DIP/ECE Dept./Rowan University

DIP: DetailsDIP: Details

G ray-level Histogram

Spatial

DF T DC T

Spectral

Digital Image Characteristics

Point Processing M asking Filtering

Enhancem ent

Degradation M odels Inverse Filtering W iener Filtering

Restoration

Pre-Processing

Inform ation Theory

LZW (gif)

Lossless

Transform -based (jpeg)

Lossy

Com pression

Edge Detection

Segm entation

Shape Descriptors Texture M orphology

Description

Digital Im age Processing

S. Mandayam/ DIP/ECE Dept./Rowan University

Recall: DCT FeaturesRecall: DCT Features

Fringe Pattern

DCT

DCT Coefficients

Zonal Mask

1 2

3

4

5

1 2 3 4 5

(1,1)(1,2)(2,1)(2,2)

.

.

.

FeatureVector

ArtificialNeuralNetwork

S. Mandayam/ DIP/ECE Dept./Rowan University

Image Segmentation Recall: Image Segmentation Recall: Edge DetectionEdge Detection

f(x,y) Gradient Mask

fe(x,y)

-1 -2 -10 0 01 2 1

-1 0 1-2 0 2-1 0 1

S. Mandayam/ DIP/ECE Dept./Rowan University

Recall: 1-D DFTRecall: 1-D DFT• Discrete Domains

• Discrete Time: k = 0, 1, 2, 3, …………, N-1• Discrete Frequency: n = 0, 1, 2, 3, …………, N-1

• Discrete Fourier Transform

• Inverse DFT

Equal time intervals

Equal frequency intervals

1N

0k

nkN2

j;e ]k[x]n[X

1N

0n

nkN2

j;e ]n[X

N1

]k[x

n = 0, 1, 2,….., N-1

k = 0, 1, 2,….., N-1

S. Mandayam/ DIP/ECE Dept./Rowan University

Description: Description: Fourier DescriptorsFourier Descriptors

demos/demo8fd/

S. Mandayam/ DIP/ECE Dept./Rowan University

Image MomentsImage Moments2-D continuous function f(x,y), the moment of order (p+q) is:

....2 ,1 ,0,

),(

qp

dydxyxfyxm qppq

Central moment of order (p+q) is:

00

01

00

10 ;

where

),()()(

m

my

m

mx

dydxyxfyyxx qppq

S. Mandayam/ DIP/ECE Dept./Rowan University

Image Moments (contd.)Image Moments (contd.)

Normalized central moment of order (p+q) is:

,.....3 ,2,for

;12

where

;00

qp

qp

pqpq

A set of seven invariant moments can be derived from pq

S. Mandayam/ DIP/ECE Dept./Rowan University

Image TexturesImage Textures

The USC-SIPI Image Databasehttp://sipi.usc.edu/

Grass Sand Brick wall

S. Mandayam/ DIP/ECE Dept./Rowan University

originX B

Erosion X} B :{x = B X x

X B

Dilation } X B̂ :{x = B X x

origin BXX B

Morphological OperationsMorphological Operations

S. Mandayam/ DIP/ECE Dept./Rowan University

origin

X

X B = (X B) B Opening

B X B

origin

X B = (X B) B Closing

X B X

B

Morphological OperationsMorphological Operations

S. Mandayam/ DIP/ECE Dept./Rowan University

Morphological Operations: Morphological Operations: MatlabMatlab

BWMORPH Perform morphological operations on binary image.

BW2 = BWMORPH(BW1,OPERATION) applies a specific morphological operation to the binary image BW1.

BW2 = BWMORPH(BW1,OPERATION,N) applies the operation N times. N can be Inf, in which case the operation is repeated until the image no longer changes.

OPERATION is a string that can have one of these values:

'close' Perform binary closure (dilation followed by erosion)

'dilate' Perform dilation using the structuring elementones(3)

'erode' Perform erosion using the structuring elementones(3)

'fill' Fill isolated interior pixels (0's surrounded by1's)

'open' Perform binary opening (erosion followed bydilation)

'skel' With N = Inf, remove pixels on the boundariesof objects without allowing objects to break apart

demos/demo9morph/

S. Mandayam/ DIP/ECE Dept./Rowan University

Lab 4: Digital Image Lab 4: Digital Image CompressionCompression

http://engineering.rowan.edu/~shreek/fall01/dip/lab4.html

S. Mandayam/ DIP/ECE Dept./Rowan University

SummarySummary