dream
DESCRIPTION
DREAM. IDEA. PLAN. IMPLEMENTATION. Introduction to Image Processing. Present to: Amirkabir University of Technology (Tehran Polytechnic) & Semnan University. Dr. Kourosh Kiani Email: [email protected] Email: [email protected] Email : [email protected] - PowerPoint PPT PresentationTRANSCRIPT
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DREAMDREAM
PLANPLANIDEAIDEA
IMPLEMENTATIONIMPLEMENTATION
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Introduction to Image ProcessingIntroduction to Image Processing
Dr. Kourosh KianiEmail: [email protected]: [email protected]: [email protected]: www.kouroshkiani.com
Present to:Amirkabir University of Technology (Tehran
Polytechnic) & Semnan University
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Lecture 04
Arithmetic Operations
Algebraic operations used for images are commonly viewed in two groups; mathematical and logical operations. Image adding, subtracting, dividing and multiplying operations constitute mathematical processing and “AND, OR, NOT” etc. operations forms logical operations.
SIMPLE ALGEBRAIC OPERATIONS in IMAGES
………
…a4a3
…a2a1
………
…b4b3
…b2b1a4
+b4a3
+b3
a2 +b2
a1 +b1
+ =
………
…a4a3
…a2a1a4
+10a3
+10
a2 +10
a1 +10
+ =10
IMAGE ADDITION
IMAGE ADDITION
C[x, y] A[x, y] B[x, y]
Reduce noise (increase SNR) averaging, smoothing ...
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+
=
IMAGE ADDITION
C[x, y] A[x, y] B[x, y]
I = imread(‘rice.tif’);J = imread(‘cameraman.tif’);K = imadd(I, J);imshow(K)
Ori=imread('rice.png');j=imread('cameraman.tif');k=i+j;imshow(k);
I = imread('kourosh.jpg');figure(1);imshow(I);I2 = imadd(I, 70);figure(2);imshow(I2);
+ 70 =
Image Averaging
Consider a noisy image g(x,y) formed by the addition of noise (x,y) to an original image f(x,y)
g(x,y) = f(x,y) + (x,y)
Image Averaging
If noise has zero mean and is uncorrelated then it can be shown that
),( yxg = image formed by averaging K different noisy images
K
ii yxg
Kyxg
1
),(1
),(
Image Averaging
Then
),(2
),(2 1
yxyxgK
= variances of g and ),(2
),(2 , yxyxg
Then if K increase, it indicates that the variability (noise) of the pixel at each location (x,y) decreases.
IMAGE AVERAGING
Average multiple images (frames) of the same scene together
Useful for removing noise
+ + . . . =
X = 255 10 75 44 225 100
Y = 50 50 50 50 50 50
Z = 205 0 25 0 175 50
X = uint8([ 255 10 75; 44 225 100]);Y = uint8([ 50 50 50; 50 50 50 ]);Z = imsubtract(X,Y)
Image Subtracting],[],[],[ yxByxAyxC
Image Subtractingrice = imread('rice.png');figure (1)imshow(rice);background = imopen(rice, strel('disk', 15));figure (2)imshow(background);rice2 = imsubtract(rice, background);figure (3)imshow(rice2);
- =
- 70 =
I = imread('kourosh.jpg');J = imsubtract(I,70);Figure(1), imshow(I), Figure(2), imshow(J)
Image Subtracting
_ =
Digital subtraction angiography (DSA)
Image Subtracting
Digital subtraction angiography (DSA)
Image Subtracting
X = 2 10 7 4 25 10
Y = 5 5 5 3 5 6
Z = 10 50 35 12 125 60
X = uint8([ 2 10 7; 4 25 10]);Y = uint8([ 5 5 5; 3 5 6 ]);Z = immultiply(X,Y)
Image Multiplying],[],[],[ yxByxAyxC
Image MultiplyingI = imread('moon.tif');figure(1)imshow(I)J = immultiply(I,0.5);figure(2)imshow(J)
* 0.5 =
X = 100 20 75 30 25 36
Y = 5 5 5 3 5 6
Z = 20 4 15 10 5 6
X = uint8([ 100 20 75; 30 25 36])Y = uint8([ 5 5 5; 3 5 6 ])Z = imdivide(X,Y)
Image Dividing],[],[],[ yxYyxXyxZ
Image DividingI = imread('rice.png');figure(1), imshow(I);background = imopen(I,strel('disk',15));figure(2), imshow(background);Ip = imdivide(I,background);figure(3), imshow(Ip, []);
÷ =
Image Dividing
÷ 2 =
I = imread('rice.png'); J = imdivide(I,2);figure(1), imshow(I)figure(2), imshow(J)
Questions? Discussion? Suggestions?
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