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Chapter 2 Digital Image Fundamentals
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Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

Jan 03, 2016

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Page 1: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

Chapter 2

Digital Image Fundamentals

Page 2: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

2.1 Human Visual System

Purpose of study : Improvement of images for use by a human observer

(1)Physical Structure of the Eye

Cornea : convex lens, refracting the rays

Aqueous humor

Iris : a variable aperture to control the amount of light

Page 3: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

Lens : Controls the focal length to focus at retina

Vitreous humor

Retina : Composed of photoreceptors to convert the intensity and color of light to neural signal

s ( 108 elements)

Types of photo Receptors

Rods : to respond to broad-spectrum color light for low-light vision, and therefore cannot discriminate color.

Cones : for day-light vision. Three different types of cones for color vision (trichromacy)

Page 4: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.
Page 5: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

Distribution of rods and cones

- Color perception is best for the objects that we are viewing directly forward

-Relative insensitivity of cones also accounts for our inability to perceive color under low-light conditions

Page 6: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

Optic nerve and visual cortex

2.2 Image Processing in the Eye

Weber’s law

Rods/ConesVisual Cortex Processing

Optic Nervelights

decisionneuralimpulses

(brain)

Page 7: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

-The difference in perceived brightness of the steps does not Appear equal-The eye cannot see the same intensity increments in the bright

regions that it sees in the dark regions

Page 8: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

Note) In DIP, simple darkening of bright regions can make undetectably minute intensity changes perceptible

Lateral Inhibitions

Simultaneous ContrastThe square in the left side is brighter than that in the right side

Page 9: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

② Match band effectVisual system accentuates sharp intensity changes Human eye is sensitive to the changes of intensities (edges)

Note : Second–Order System

Frequency Response of HVS

Page 10: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

Size of image : M x M

fmax = M/2/ = M/2(Cycles / degree)

= 2tan-1(0.5x/6H) (degree)

Page 11: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

Sensitivity curve

Other Properties of HVS : Digital Picture Processing, volume 1, Chapter3, Azriel Rosenfeld and Avinash C. kak

Page 12: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

2.3 Sampling and Quantization

Uniform sampling and quantization

F(x,y) = f(0,0) f(0,1) …………… f(0,M-1) f(1,0) f(1,1) …………… f(1,M-1)

f(N-1,0) f(N-1,1) ….. f(N-1,M-1) N x M

Size of DIN = 2n , M = 2k

Gray levelG = 2m

# of bits = N x M x m

Page 13: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

Effect of Image Resolution

(a)1024 x 1024

(b) 512 x 512 (c) 256 x 256

(d) 128 x 128 (e) 64 x 64 (f) 32 x 32

Page 14: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

Effect of Quantization Levels

(a) 8 bit (b) 7 bit (c) 6 bit (d) 5 bit

(e) 4 bit (f) 3 bit (g) 2 bit (h) 1 bit

Page 15: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

Isopreference curves

Figure 2.12 Isopreference curves for (a) face (b) cameraman, and (c) crowd. (From Huang [1965]

-The quality of the images tends to increase as N and m are increased Note : Exceptional Case

For fixed N, the quality is improved by decreasing m.(contrast)

Page 16: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

-The curves tend to become more vertical Note : For images with a large amount of detail only a few

gray levels are needed

-The curves depart markedly from the curves of constant b = N2m

Non-uniform Sampling / Quantization

- Fine sampling is the neighborhood of sharp gray-level transitions whereas coarse sampling in relatively smooth regions-Quantization according to the sensitivity of HVS. (Subband Coding)

Page 17: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

2.4 Some Basic Relationships Between Pixel

Neighbor of a pixel

N8(p) = N4(p) ND(p)

xpx xx

N4(p)

ND(p) pxx

x x

N8(p)x

xx

xp xx

xx

Page 18: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

Connectivity

V = Set of gray- level values used to define connectivity

qpq qq

p and one of q V

- 4-connectivity

q

qq

qp qq

qqp and one of q V

- 8-connectivity

Page 19: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

- m-connectivity① q is in N4(p) or

② q is in ND(p) and the set N4(p) N4(q) is empty

- A pixel p is adjacent to a pixel q if they are connected- Path / length (x0, y0)(x1,y1)…(xn, yn)

Page 20: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

- ConnectedIf p and q pixels of an image subset S , then p is connected to q in S if there is a path from p to q consisting entire of pixels in S

- Connected component SFor any pixel p in S , the set of pixels in S that are connected to p

Page 21: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

Labeling of Connected Components

- With 4-Connected Components :

r p

t

If p = 0, move to next scanning position Otherwise (p=1),

if r = t = 0, then assign a new labelif , then assign the label that is equal to 1

if r = t = 1 , and they have the same label, then assign the label

if r = t= 1 , and they have the different labels, then assign one of the labels and make a notethey are equivalent

merge the equivalent labels

0

1or

0

1

r

t

t

r

Page 22: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

- With 8-connected components

r pts q

If p=0 then move to next positionIf p=1 then

If only one of neighbors is equal to 1 , thenassign the label.

If none of neighbors is equal to 1, thenassign a new label.

If two or more neighbor are equal to 1, andthey have different labels, then assign are of thenand make note that they are equivalent label.

Merge the equivalent labels

Page 23: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

Relations, Equivalence, and Transitive Closure

- Binary Relation R on set A

Ex.

R = relation of 4-connected

Definitions : Equivalence Relations (a) reflexive if for each a ∈ A , aRa (b) symmetric if for each a and b ∈ A, aRb → bRa (c) transitive if for a, b, and c ∈ A, aRb and bRc → aRc

Property : If R is an equivalence relation on a set A, then A can be divided into disjoint subsets, called equivalence classes.

4321 ,,, ppppA

4

3

21

p

p

pp

13311221 ,,,,,,, ppppppppR

AAaRb

Page 24: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

Ex.

00000

00010

10000

01000

00011

e

d

c

b

a

B

edcba

Note : reflexive relation every diagonal element = 1 symmetric relation symmetric matrix

ecbddbbaaaR ,,,,,,,,

Adjacent Matrix

Page 25: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

- Transitive Closure of R : R+

Ex.

00000

01010

10000

01010

01011

e

d

c

b

a

B

edcba

Note : 1) bRd and dRb bRb dRb and bRd dRd2) B+ = B + BB + BBB + + (B)n

multiplication ANDaddition OR

Page 26: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

Distance Measures

D is a distance function or metric if

2

212

21012

212

2

||||),(

distance)Block (city distance

4

4

2122

tysxqpD

D

s,t, qx,y p

tysxp,qD/

e

D(q,z)D(p,q)D(p,z)

D(p,q),D(p,q)

q) p (D(p,q)qpD

and

iff00),(

Ex) Euclidean Distance

Page 27: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

length of the shortest path = distance in D4 and D8

length of path in m-connectivity not unique

Ex)

p

pp

pp

21

43

)1(

)1()0(

)1()0(

21

43

p

pp

pp

m-distance from p to p4 = 2

)1(

)1()0(

)1()1(

21

43

p

pp

pp

)1(

)1()1(

)1()0(

21

43

p

pp

pp

or

m-distance from p to p4 = 3

22222

21112

21012

21112

22222

t||ys||x(p,q)D

D

, max

distance) board-(chess distance

8

8

Page 28: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

Relations, Equivalence, and Transitive Closure

- Binary Relation R on set A

AA b R a

)}p ,(p ),p,(p ),p ,(p ),p ,(p {R

p

p

pp

connected-4 ofrelation R

} p ,p ,p ,p { A

13311221

4

3

21

4321

Ex.

c R a a R b and b R a ,A c and b, a,for if ve transiti(c)

a R b b R a A, b and aeach for if symmetric (b)

a R a A, aeach for if reflexive (a)

Relations eEquivalenc : sDefinition

Page 29: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

Property : If R is an equivalence relation on a set A , then A can be divided into & disjoint subsets, called equivalence classes

00000

00010

10000

01000

00011

e

d

c

b

a

β

edcba

MatrixAdjacent

e)}(c, b),(d, d),(b, b),(a, a),(a, { R

Note : reflexive relation every diagonal element = 1

symmetric relation symmetric matrix

Ex.

Page 30: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

- Transitive Closure of R : R+

00000

01010

10000

01010

01011

e

d

c

b

a

β

edcba

Note : 1)

n(B) BB B B

d R d d R b and b R d

b R b b R d and d R b

2)

multiplication ANDaddition OR

Page 31: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

Arithmetic and Logic Operations

-pixel by pixel operation :p + q p AND qp – q p OR qp * qp / q

Multiplicationpixel

Binary image

Note : Quantization of Gray-level image <pixel wise>

3} 2, 1, 0, { 255} , 1, ,0{

Page 32: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

Ex. Some Examples of Logic Operations on Binary Images

Page 33: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

- neighborhood oriented operation : mask operation

a

iii zwzwzwzwzw

199332211 z

w1 w2 w3

w4 w5 w6

w7 w8 w9

Computationally expensive operation 512 × 512 3 × 3 maskMultiplication 9 × 512 × 512 operationAddition 8 × 512 × 512parallel operation is needed.

- object oriented operation

Note : The complexity and parallel architecture that depends onthe operation look-up Table / SIMD / MIMD

Page 34: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

Imaging Geometry

Some basic Transform

- Translation

0*

0*

0*

Z ZZ

Y YY

XXX

ZYX

000 ZYX *** ZYX

11000

100

010

001

1

1100

010

001

0

0

0

*

*

*

0

0

0

*

*

*

Z

Y

X

Z

Y

X

Z

Y

X

Z

Y

X

Z

Y

X

Z

Y

X

V* = T · V

X

000 ZYX

Z

Y

z

x

y

World coordinate system (X,Y,Z)

Page 35: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

Note : Movement of object point in the same coordinate systems

Ex. ),,( )0,0,0( 000 ZYX

Change of coordinate systems for on object point

1000

100

010

001

),,(),,()0,0,0(),,(

0

0

0

1

000***

Z

Y

X

T

ZYXZYXZYX

Ex.)0,0,0(),,( )0,0,0( 1000T

TZYX

Page 36: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

- Scaling By factors Sx, Sy, Sz along X, Y, Z axis

1000

000

000

000

z

y

x

S

S

S

S

- Rotation

Y

Z

X

rotation about z-axis

1000

0100

00cossin

00sincos

θα

θ

θ

Page 37: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

rotation about x-axis

1000

0cossin0

0sincos0

0001

R

rotation about y-axis

1000

0cos0sin

0010

0sin0cos

R

- Concatenation and inverse transform

AvTvSRv ))((* , where STRA

For m-points,

AVV *

V

m

Page 38: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

- Inverse Transform

1000

100

010

001

0

0

0

1

Z

Y

X

T

1000

0100

00cossin

00sincos

1

R

Perspective Transform

y,Y

Image plane

x,X

z,Z

(X,Y,Z)

(x,y)

Lens center

Z

X

Z

Xx

Z

Y

Z

Yy

Z

Yy

Z

Xx

Page 39: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

- Homogeneous coordinates

Z

Y

X

w h

Z

Y

X

w

11

00

0100

0010

0001

P

ZZ

Y

X

Z

Y

X

ch

11

00

0100

0010

0001

Pw h

Z

ZZ

YZ

X

Z

Y

X

c

Page 40: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

- Inverse perspective transform

hh cw -1P

11

00

0100

0010

0001

1

P

0

y

x

c

0

0

0

h0

0

y

x

c

0

0

y

x

0

00

0

y

x

wwh

ZX

0x ZY

0y

Note : It is a useless result. It should be as follows.

Page 41: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

z

y

x

c 0

0

0

0

0

h

z

y

x

c

Free variable

z

zz

yz

x

wz

z

y

x

cw hh

0

0

0

0

0

1-

Z

Y

X

P

z

zZ

z

yY

z

xX

0

0

0

zyY

zx

X

0

0

Note : Inverse does not uniquely exist. Therefore we introduce the free variable z

Page 42: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

Camera Model

W in world coordinates (X,Y,Z) w in camera coordinate (x,y,z) c is image coordinate (x,y,0)

The world coordinate should be aligned with the camera coordinates (X,Y,Z)

- displacement of gimbal center form the origin

1000

100

010

001

0

0

0

Z

Y

X

G

Fig 2.18 Imaging geometry with two coordinate systems

Page 43: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

- Pan the x-axis with respect to z-axis : θR

- Tilt the z-axis with respect to x-axis : αR

Note : and are the positive angle with respect to CCW direction α θ

- Displacement of the image plane with respect to the gimbal center

1000

100

010

001

3

2

1

r

r

r

Ch

hh

GwRPCR

PCRGwc

λrα)Z(Zθ)Y(Yαθ)X(X

rθ)Y(Yθ)X(Xλx

3000

100

cossincossinsin

sincos

3000

2000

cossincossinsin

sin)(coscoscossin

r)Z(Zθ)Y(Yαθ)X(X

rZZθ)Y(Yθ)X(Xλy

Page 44: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

Example :

m.y

m.x.λ

λ.

.λy

λ.

.λx

0090

00070 0350

531

420531

030

(1,1,0.2)Z)Y,(X,

0.035m35mmλ 0.02mrr 0.03mr

135θ 135α

1m Zm 0Y m 0X

321

000

Fig 2.19 Camera viewing a 3-D scene

Page 45: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

Camera Calibration

hh Awc

PCRGA

Lettering k=1 is the homogeneous representation yields

Eq.(2) 0aaaaaaaa

0aaaaaaaa

Eq.(1)

/

/

1

2444434241232221

1444434241131211

444342414

242322214

141312114

42

41

44434241

14131211

4

3

2

1

yyZxYyXZYX

xxZxYxXZYX

aZaYaXac

aZaYaXayc

aZaYaXaxc

ccy

ccx

Z

Y

X

aaaa

aaaa

c

c

c

c

h

h

h

hh

hh

h

h

h

h

Page 46: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

Note : There are 12 unknown parameters in Eq(1) and two equation as Eq(2).

That means we need more than 6 world points and 6 imagepoints to solve the 12-parameters.

Stereo Imaging

Fig 2.21 Model of the stereo imaging process.

Page 47: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

12

11

21

1221

22

2

11

1

x

x

XX and Z

:

:

xx

BZZXZBX

BZZ

Zx

X

Zx

X

When the first camera is coincide with the world coordinate system

When the second camera is coincide with the world coordinate system

Fig 2.22 Top view of Fig 2.21 with the first camera brought into coincidence with the world coordinate system.

Note : 1. Correspondence Problem to find Depth-Map. Area Based Matching Feature Based Matching 2. Constraints to find the Correspond- -ing points. Epipolar Constraints Ordering Constraints

Page 48: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

Photographic Film

- Film Structure and Exposure

(ⅰ) Supercoat for protection.(ⅱ) Emulsion layer of minute silver halide crystals.(ⅲ) Substrate layer to promote adhesion of the emulsion to the film base.(ⅳ) Film base made of cellulose triacetate.(ⅴ) Backing layer to prevent curling.

Light energy the grain containing tiny patches of metallic silver (development centers)Developing : The single development center in a silver halide

grain can participate the change of the entire grain to metallic silver.

Chemical removal of the remaining silver halide grains(opaque)Negative Film.

Light energy negative filmpaper coated silver halide(positive image)

Page 49: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

- Film Characteristics

Contrast

Exposal : E = IT ( Energy per unit area) I = Incident Intensity T = Duration of Exposal

Note : As the slope of linear region increases, the contrast of film is increased.

2.0

1.0

0.0

Toe

Linearregion

Shoulder

Densi

ty

Grossfog

tan α = γ

α

log EFig 2.24 A typical H & D curve.

Page 50: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

Speed : (감광도 )

To determine how much light is needed to produce a certain of silver on development.The lower the speed, the longer the film must be exposed to record a given image.

Note : ASA scale ASA 200 is twice as fast (and for a given subject requires

half as much exposure) as a film of ASA 100.

ASA PURPOSE

ASA 80~160 General purpose outdoor and some indoor photography

ASA 20~64 Fine grain film for maximum image definition

ASA 200~600

High speed films for poor light and indoor photography

ASA 650~ Ultra-speed films for very poor light

Page 51: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

Graininess

-Fast film (large ASA number) has the large graininess.-Slow film (small ASA number) is preferable where fine detail is desired or where enlargement of the negatives is necessary.

Resolving power

-Depends on the graininess, on the light scattering properties of the emulsion, and on the contrast with which the film reproduces fine details.

Note : Fine-grain films with thin emulsions yields the highest resolving power.

Page 52: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

Diaphragm ( 조리개 ) and Sutter Speed

Diaphragm : f-number or stop number

32} 22, 16, 11, 8, 5.6, 4, 2.8, 2, {1.4,

Note : ⅰ) f-number is inversely proportional to the amount of light admitted.

ⅱ) Each setting admits twice as much light as the next higher f-number (this giving twice as much exposure)

Speed : } sec 10001,500

1,1251 ,60

1 ,301 ,15

1 ,81 ,4

1 ,21 {1,

Note : ⅰ) The faster the shutter speed, the shorter the exposure time obtained.

ⅱ) For the same exposure,

601 with 5.6

f 1251 with 4

f 2501 with 2.8

f

Page 53: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

Field of View

cf d

w

d

wf c

d

w

f

c

Ex.

pixelCm

3

1 m

300

1

103

cellm 10

1001

1 w'

cells, 100100 hasarray CCD If

m 3

1

103

10 1

f

cd w

m 1 d

m10 3 3Cm f

m10 m10 cc

2

2

2-

2-

2-

-2-2

FOV

Page 54: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

Depth of Field

z′ -z

Optical Origin

DOFImage plane

Object

LensFocal length = f

z′: camera constant

Lens equation :

fzz

111

(distance from the optical origin to image plane)

Page 55: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

i)

ii)

fz z then ,

1

or )(

)(

111

zf

fz

fz

zfz

z)f(

fz)(

fz

fz

zfz

iii) If an object is focused at distance (-z), then the other lights from other distance of objects may not be focused at They will make several pixels to be sensitized. DOF is defined the margin of the distance in (-z) that limits the sensitized pixel within one CCD element.

Note :

z

Page 56: Chapter 2 Digital Image Fundamentals. 2.1 Human Visual System Purpose of study : Improvement of images for use by a human observer (1)Physical Structure.

View Volume

Homework : 2.4, 2.5, 2.10, 2.13, 2.16, 2.17

Due :

imageplane

lens

DOF

FOV

View volume = DOF FOVx