Docsity
Docsity

Prepare for your exams
Prepare for your exams

Study with the several resources on Docsity


Earn points to download
Earn points to download

Earn points by helping other students or get them with a premium plan


Guidelines and tips
Guidelines and tips

DIGITAL IMAGE REPRESENTATION AND TRANSFORMS, Essays (university) of Digital Image Processing

2.1 Elements of visual perception 2.2 Light and the electromagnetic spectrum 2.3 Image sensing and acquisition 2.4 Image sampling and quantization 2.5 Some basic relationships between pixels 2.6 Linear and Nonlinear Operations

Typology: Essays (university)

2017/2018

Uploaded on 01/03/2018

ramesh-smartcatty
ramesh-smartcatty 🇮🇳

1 document

1 / 29

Toggle sidebar

This page cannot be seen from the preview

Don't miss anything!

bg1
1
Digital Image Processing, 2nd ed.
Digital Image Processing, 2nd ed. www.imageprocessingbook.com
© 2002 R. C. Gonzalez & R. E. Woods
Chapter 2 Digital Image fundamentals
Chapter 2 Digital Image fundamentals
2.1 Elements of visual perception
2.2 Light and the electromagnetic spectrum
2.3 Image sensing and acquisition
2.4 Image sampling and quantization
2.5 Some basic relationships between pixels
2.6 Linear and Nonlinear Operations
Digital Image Processing, 2nd ed.
Digital Image Processing, 2nd ed. www.imageprocessingbook.com
© 2002 R. C. Gonzalez & R. E. Woods
2.1 Elements of visual perception
2.1 Elements of visual perception
2.1.1 Structure of the Human Eye
2.1.1 Structure of the Human Eye
(角膜)
(虹膜,光圈)
(睫狀肌)
(睫狀纖維)
(視軸)
(玻璃狀液體)
(視網膜中央窩)
(盲點)
(視網膜,底片)
(脈絡膜)
(鞏膜)
(水晶體)
(前室)
(睫狀體
,變焦)
20mm
(視神經及護套)
Conjunctiva(節膜)Pupil(瞳孔)
曲率不同
pf3
pf4
pf5
pf8
pf9
pfa
pfd
pfe
pff
pf12
pf13
pf14
pf15
pf16
pf17
pf18
pf19
pf1a
pf1b
pf1c
pf1d

Partial preview of the text

Download DIGITAL IMAGE REPRESENTATION AND TRANSFORMS and more Essays (university) Digital Image Processing in PDF only on Docsity!

© 2002 R. C. Gonzalez & R. E. Woods

Chapter 2 Digital Image fundamentalsChapter 2 Digital Image fundamentals

2.1 Elements of visual perception

2.2 Light and the electromagnetic spectrum

2.3 Image sensing and acquisition

2.4 Image sampling and quantization

2.5 Some basic relationships between pixels

2.6 Linear and Nonlinear Operations

Digital Image Processing, 2nd ed. Digital Image Processing, 2nd ed. (^) www.imageprocessingbook.com

2.1 Elements of visual perception 2.1 Elements of visual perception

2.1.1 Structure of the Human Eye 2.1.1 Structure of the Human Eye

,

( )

≈20mm

Conjunctiva Pupil

© 2002 R. C. Gonzalez & R. E. Woods

„ „ Light ReceptionLight Reception

ƒ Cones

ƒ 6-7millions ƒ sensitive to Color ƒ Photopic or Bright-light vision

ƒ Rods

ƒ 75-150millions ƒ Scotopic or Dim-light vision

2.1 Elements of visual perception 2.1 Elements of visual perception

2.1.1 Structure of the Human Eye 2.1.1 Structure of the Human Eye

Digital Image Processing, 2nd ed. Digital Image Processing, 2nd ed. (^) www.imageprocessingbook.com

2.1 Elements of visual perception 2.1 Elements of visual perception

2.1.1 Structure of the Human Eye 2.1.1 Structure of the Human Eye

© 2002 R. C. Gonzalez & R. E. Woods

2.1 Elements of visual perception 2.1 Elements of visual perception

„ „ 2.1.2 Image formation in the Eye2.1.2Image formation in the Eye

– Len

– Fovea

14mm ~ 17mm

2.55mm

Digital Image Processing, 2nd ed. Digital Image Processing, 2nd ed. (^) www.imageprocessingbook.com

„„^ 2.1.32.1.3 Brightness adaptation and discriminationBrightness adaptation and discrimination

– Subjective Brightness is a logarithm function

  • on the order of 10 10

– The total range of distinct intensity levels it can

discriminate simultaneously is rather small

milliLambert:

2.1 Elements of visual perception 2.1 Elements of visual perception

© 2002 R. C. Gonzalez & R. E. Woods

2.1 Elements of visual perception 2.1 Elements of visual perception

„„ A classic experiment for brightness discriminationA classic experiment for brightness discrimination

– Weber Ratio : ∆ Ic / I

  • a small value means Good brightness discrimination
  • a large value means Poor brightness discrimination

– the typical observer can discern 1~2 dozen different

intensity changes

Scotopic Photopic

Digital Image Processing, 2nd ed. Digital Image Processing, 2nd ed. (^) www.imageprocessingbook.com

2.1 Elements of visual perception 2.1 Elements of visual perception

„„^ Two examplesTwo examples

ƒ to demonstrate the perceived brightness is not a simple

function of intensity

ƒ Mach Bands - 1865, Ernst Mach

© 2002 R. C. Gonzalez & R. E. Woods

2.1 Elements of visual perception 2.1 Elements of visual perception

Digital Image Processing, 2nd ed. Digital Image Processing, 2nd ed. (^) www.imageprocessingbook.com

2.1 Elements of visual perception 2.1 Elements of visual perception

© 2002 R. C. Gonzalez & R. E. Woods

2.1 Elements of visual perception 2.1 Elements of visual perception

Digital Image Processing, 2nd ed. Digital Image Processing, 2nd ed. (^) www.imageprocessingbook.com

2.1 Elements of visual perception 2.1 Elements of visual perception

© 2002 R. C. Gonzalez & R. E. Woods

2.1 Elements of visual perception 2.1 Elements of visual perception

Digital Image Processing, 2nd ed. Digital Image Processing, 2nd ed. (^) www.imageprocessingbook.com

2.2 Light and the Electromagnetic Spectrum 2.2 Light and the Electromagnetic Spectrum

„„^ Electromagnetic Spectrum(Electromagnetic Spectrum(^ ))

© 2002 R. C. Gonzalez & R. E. Woods

„ Wavelength λ

h = 6. 626068 × 10 −^34 Js 1 eV = 1. 6 × 10 −^19 J

2.2 Light and the Electromagnetic Spectrum 2.2 Light and the Electromagnetic Spectrum

Digital Image Processing, 2nd ed. Digital Image Processing, 2nd ed. (^) www.imageprocessingbook.com

2.2 Light and the Electromagnetic Spectrum 2.2 Light and the Electromagnetic Spectrum

„ Visible Band

„430um~790nm „Illuminant ( ) „reflected light from objects ( ) „Achromatic or Monochromatic (Gray Level) „Chromatic - Color „Light Source „ Radiance ( ) - measured in Watts „ Luminance ( ) - measured in lumens „ Brightness ( ) - subjective descriptor

© 2002 R. C. Gonzalez & R. E. Woods

2.3 Image Sensing and Acquisition 2.3 Image Sensing and Acquisition

„„ 2.3.12.3.1 Image acquisition using a single sensorImage acquisition using a single sensor

ƒ Photodiode( )

Digital Image Processing, 2nd ed. Digital Image Processing, 2nd ed. (^) www.imageprocessingbook.com

2.3 Image Sensing and Acquisition 2.3 Image Sensing and Acquisition

„„^ 2.3.22.3.2 Image acquisition using sensor stripsImage acquisition using sensor strips

Scanning Direction

CAT MRI PET

Flatbed Scanner

© 2002 R. C. Gonzalez & R. E. Woods

2.3 Image Sensing and Acquisition 2.3 Image Sensing and Acquisition

„„ 2.3.32.3.3 Image acquisition using sensor arraysImage acquisition using sensor arrays

ƒ Charged Couple Diode (CCD)

IrisLens Digital Camera

SunLamp Flash

CCDCMOS

Digital Image Processing, 2nd ed. Digital Image Processing, 2nd ed. (^) www.imageprocessingbook.com

2.3 Image Sensing and Acquisition 2.3 Image Sensing and Acquisition

© 2002 R. C. Gonzalez & R. E. Woods

„ Typical values of i(x,y)

„ i = 90000 lm/m^2 „ i = 10000 lm/m^2 „ i = 0.1 lm/m^2 „ i = 1000 lm/m^2

„ Typical values of r(x,y)

„ r = 0. „ r = 0. „ r = 0. „ r = 0. „ r = 0.

2.3 Image Sensing and Acquisition 2.3 Image Sensing and Acquisition

Digital Image Processing, 2nd ed. Digital Image Processing, 2nd ed. (^) www.imageprocessingbook.com

„ Intensity at (x 0 , y0 )

„ [ Lmin , L max ] is called gray scale

„ Shift this interval to [0, L - 1]

„ l = 0 is black „ l = L - 1 is white „All intermediate values are shades of gray

l = f ( x 0 , y 0 ) (2.3-5)

L min ≤ l ≤ L max (2.3- 6)

L min = i min r min

L max = i max r max

2.3 Image Sensing and Acquisition 2.3 Image Sensing and Acquisition

© 2002 R. C. Gonzalez & R. E. Woods

2.4 Image sampling and quantization 2.4 Image sampling and quantization

„„ 2.4.1 Basic concepts in sampling and quantization2.4.1 Basic concepts in sampling and quantization

Digital Image Processing, 2nd ed. Digital Image Processing, 2nd ed. (^) www.imageprocessingbook.com

2.4 Image sampling and quantization 2.4 Image sampling and quantization

Sampling ( Sampling ( )) Quantization (Quantization( ))

© 2002 R. C. Gonzalez & R. E. Woods

2.4 Image sampling and quantization 2.4 Image sampling and quantization

„„ 2.4.3 Spatial and Gray-Level Resolution2.4.3 Spatial and Gray-Level Resolution

„ Spatial Resolution

Digital Image Processing, 2nd ed. Digital Image Processing, 2nd ed. (^) www.imageprocessingbook.com

2.4 Image sampling and quantization 2.4 Image sampling and quantization

© 2002 R. C. Gonzalez & R. E. Woods

2.4 Image sampling and quantization 2.4 Image sampling and quantization

Gray-Level Resolution

Digital Image Processing, 2nd ed. Digital Image Processing, 2nd ed. (^) www.imageprocessingbook.com 2.4 Image sampling and quantization 2.4 Image sampling and quantization

Gray-Level Resolution