Image 2

Subject : T0934 / Multimedia Programming FoundationSession : 5Tahun : 2009Versi : 1/0

Bina Nusantara

Learning Outcomes

In the end of this session, students must be able to: – Understand the basic principal

of image transformation and enhancement

– Apply correct Java syntax to transform, enhance, and display an image

Course Outlines

• Digital Image Definition• Image Transformation• Image Enhancement• Java 2D API

Bina Nusantara

Digital Image Definition

• Image array of pixel Z(x,y)

Bina Nusantara

N

M

Z

X = width (0 – N)Y = height (0 – M) Z = pixel values

X = width (0 – N)Y = height (0 – M) Z = pixel values

X

Y

0

Digital Image Definition

• Image Z(x,y)• Z refers to RGB values or brightness

Bina Nusantara

Image Transform in Java

• drawImage– draw and scale an image

• ConvolveOp – blur or sharpen an image

• AffineTransformOp – transform an image

• Graphics2D.setClip – crop an image

Bina Nusantara

Image Enhancement in Java

•LookupOp– remap pixel colors (ex : a negative

image)

•RescaleOp – lighten/darken or reduce/increase

opacity of the image

Bina Nusantara

drawImage

Bina Nusantara

This is an example to draw image with Java2D

Image Transformation

newZ (x,y) = F(Z(x,y))= result of a Function

based on originalZ(x,y)

Horizontal Flipping x’ = N – xy’ = y

Bina Nusantara

Image Transformation

• Vertical Flippingx’ = xy’= M - y

Bina Nusantara

Image Transformation

• Rotation

Bina Nusantara

x' cos a -sin a 0 x y' = sin a cos a 0 y z' 0 0 1 Z

a

Matrix / KernelMatrix / Kernel

Image Rotation

• The basic algorithm is not used in practice– contains unwanted gaps or holes usually requires a greater

number of pixels than the source to properly display the rotation

• Therefore, interpolation is used to solve this problemBina Nusantara

Gaps/holesGaps/holes

Image Interpolation

Bina Nusantara

Interpolation

InterpolationInterpolation

using known data to estimate values at

unknown points.

using known data to estimate values at

unknown points.

Image Transformation

• Cropping

• Scale• Shear

Bina Nusantara

AffineTransformOp

Bina Nusantara

Rotate

Full codes are downloadable in Additional Material

AffineTransformOp

Bina Nusantara

Shear

Full codes are downloadable in Additional Material

AffineTransformOp

Bina Nusantara

Scale

Full codes are downloadable in Additional Material

AffineTransformOp

Bina Nusantara

Translate

Full codes are downloadable in Additional Material

Scale

Bina Nusantara

x’

y’

1

sx 0 0

0 sy 0

0 0 1

x

y

1

= *

RescaleOp

Bina Nusantara

Rescaling

Full codes are downloadable in Additional Material

Shear

Bina Nusantara

x’

y’

1

1 h 0

0 1 0

0 0 1

x

y

1

= *

Image Enhancement

Convolution • an operation in which the final pixel is the weighted sum of

the neighboring pixels• Use matrix/kernel as well convolution kernel / linear filter

Bina Nusantara

Convolution

• Blurring

Bina Nusantara

1 2 12 4 21 2 1

XYZ

Note : This is only an example of many blur kernel variations

Convolution

• Sharpening

Bina Nusantara

-1 -1 -1-1 9 -1-1 -1 -1

XYZ

Note : This is only an example of many sharpen kernel variations

Convolution

• Edge Detection

Bina Nusantara

-1 -1 -1-1 8 -1-1 -1 -1

XYZ

Note : This is only an example of many edge detection kernel variations

ConvolveOp

Bina Nusantara

Blur Full codes are downloadable in Additional Material

ConvolveOp

Bina Nusantara

Sharpen Full codes are downloadable in Additional Material

ConvolveOp

Bina Nusantara

Edge Full codes are downloadable in Additional Material

Image Enhancement

• Brighten/Darken

• Opacity

Bina Nusantara

Brighten Darken

Opacity 80% Opacity 50%

Graphics2D.setClip

Bina Nusantara

setClip is used to clip a portion of images to make a new image

LookupOp

Bina Nusantara

Invert Color

Full codes are downloadable in Additional Material

References

• Image Processing with Java 2D. 2008. http://www.javaworld.com/javaworld/jw-09-1998/jw-09-media.html?page=3

• Image Processing and Enhancement. 1999. http://java.sun.com/j2se/1.3/docs/guide/2d/spec/j2d-image.fm8.html

• Image Processing Fundamentals. 2009. http://www.ph.tn.tudelft.nl/Courses/FIP/noframes/fip.html

• Basic Concepts in Digital Image Processing. 2004. http://micro.magnet.fsu.edu/primer/digitalimaging/javaindex.html

• The Digital Darkroom. 2003. http://www.spinroot.com/pico/a3.pdf• Transforming Shapes, Text, and Images. 2008.

http://java.sun.com/docs/books/tutorial/2d/advanced/transforming.html• Digital Image Interpolation. 2009.

http://www.cambridgeincolour.com/tutorials/image-interpolation.htm• Image Convolution. 2009. http://www.eas.asu.edu/~karam/2dconvolution/• Image Filtering with GLSL - Convolution Kernels. 2009.

http://www.ozone3d.net/tutorials/image_filtering.php• Fundamentals of Image Processing. 2009.

http://www.cs.dartmouth.edu/~farid/tutorials/fip.pdf

Bina Nusantara