Preface ........................................................ xv
Acknowledgments .............................................. xvii
Acronyms and Abbreviations .................................... xix
Chapter 1 Introduction ......................................... 1
1.1 Acquisition ................................................ 1
1.2 Preprocessing .............................................. 3
1.3 Analysis and Measurement ................................... 5
1.4 Overview of Text ........................................... 8
References ................................................ 11
Chapter 2 Human Vision ........................................ 13
2.1 Sources of Light .......................................... 13
2.2 The Human Eye ............................................. 15
2.3 Stimulus Measurement ...................................... 18
2.4 Brightness Thresholds ..................................... 24
2.4.1 Absolute threshold ................................. 24
2.4.2 Differential threshold ............................. 25
2.4.3 Adaptation ......................................... 26
2.5 Contrast .................................................. 27
2.6 Visual Acuity ............................................. 30
2.7 Flicker ................................................... 31
2.8 Spatio-Temporal Effects ................................... 32
References ................................................ 35
Chapter 3 Image-Forming Optics ................................ 39
3.1 Optical Glass ............................................. 40
3.2 Geometrical Optics ........................................ 41
3.3 Lens Equations ............................................ 44
3.3.1 Simple thin lens ................................... 44
3.3.2 Compound thin lens ................................. 46
3.3.3 Thick lens ......................................... 48
3.3.3.1 Ball lens .................................. 48
3.3.3.2 Cylindrical lens .......................... 48
3.3.3.3 Condenser lens ............................ 49
3.3.3.4 Fresnel lens .............................. 50
3.3.3.5 Micro lenses .............................. 50
3.3.3.6 Extension tube ............................ 50
3.4 Aperture Stop, ƒ-Number, and Speed ........................ 52
3.5 Focusing and Depth of Field ............................... 59
3.6 Resolving Power ........................................... 60
3.7 Aberration ................................................ 65
3.7.1 Monochromatic aberrations .......................... 65
3.7.1.1 Spherical aberrations ..................... 65
3.7.1.2 Astigmatism ............................... 66
3.7.1.3 Coma ...................................... 66
3.7.1.4 Field curvature ........................... 66
3.7.1.5 Distortion ................................ 66
3.7.2 Chromatic aberrations .............................. 68
3.8 Optical Coatings .......................................... 69
3.9 Optical Filters ........................................... 70
3.9.1 Absorption filters ................................. 71
3.9.2 Interference (bandpass) filters .................... 71
3.10 Plastic lens .............................................. 72
References ................................................ 73
Chapter 4 Scene Illumination .................................. 75
4.1 Radiant Sources ........................................... 75
4.2 Types of Illuminators ..................................... 77
4.3 Optical Properties of Targets ............................. 78
4.3.1 Reflective materials ............................... 78
4.3.2 Transmissive materials ............................. 79
4.3.3 Absorptive materials ............................... 80
4.4 Lighting Methods .......................................... 80
4.4.1 Front lighting ..................................... 80
4.4.2 Backlighting ....................................... 81
4.4.3 Specular illumination .............................. 82
4.4.4 Beamsplitter and split mirror ...................... 83
4.4.5 Retroreflector ..................................... 83
4.4.6 Structured lighting ................................ 85
4.5 Polarization of Light ..................................... 85
4.6 Fiber Optic Lighting ...................................... 92
4.6.1 Light gathering .................................... 95
4.6.2 Transmission characteristics ....................... 97
References ............................................... 101
Chapter 5 Image Sensors ....................................... 103
5.1 Photogeneration .......................................... 104
5.1.1 Critical wavelength ............................... 104
5.1.2 Absorption coefficient ............................ 105
5.2 Photoconductor ........................................... 107
5.3 Photodiode ............................................... 109
5.4 CMOS Image Sensor ........................................ 115
5.5 Metal-Oxide Gate ......................................... 118
5.6 Charge-Coupled Devices ................................... 121
5.6.1 Charge-transfer efficiency ........................ 125
5.6.2 Blooming .......................................... 127
5.6.3 Illumination geometry ............................. 127
5.7 Line-Scan Imaging ........................................ 127
5.8 Area-Scan Imaging ........................................ 130
5.9 Related Topics ........................................... 136
5.9.1 Pixel size ........................................ 136
5.9.2 Color-filter array ................................ 137
5.9.3 Noise ............................................. 139
5.9.4 CMOS versus CCD ................................... 140
5.9.5 Scan pattern ...................................... 142
5.9.6 Pixel ordering .................................... 145
5.9.7 Incident photons .................................. 146
Appendix 5A: Semiconductor Properties ........................ 150
5A.1 Optical Materials ........................................ 151
5A.2 Doping of Semiconductors ................................. 151
5A.3 Carrier Generation ....................................... 152
5A.4 Optical Sensors .......................................... 154
5A.5 Semiconductor Terminology ................................ 154
References ............................................... 156
Chapter 6 Imaging Hardware ................................... 161
6.1 Image Display ............................................ 161
6.2 Liquid Crystal Display ................................... 169
6.3 Framegrabber ............................................. 173
6.3.1 Analog front end .................................. 179
6.3.2 Timing pulses ..................................... 179
6.3.3 Pixel clock ....................................... 179
6.3.4 Gray-level digitization ........................... 180
6.3.5 Look-up table ..................................... 180
6.3.6 Image store ....................................... 181
6.3.7 Dedicated processor ............................... 182
6.3.8 Video sampling frequency .......................... 182
6.4 Latency Parameters ....................................... 184
6.4.1 Capture latency ................................... 185
6.4.2 Transfer latency .................................. 190
6.4.3 Effects of latency ................................ 191
6.5 Resolution ............................................... 194
6.5.1 Gray-level resolution ............................. 194
6.5.2 Pixel resolution .................................. 194
6.5.3 Spatial resolution ................................ 194
6.5.4 Assessment of resolution .......................... 198
References ............................................... 201
Chapter 7 Image Formation .................................... 203
7.1 Field of View ............................................ 208
7.2 Depth of Field ........................................... 211
7.3 Image Intensity .......................................... 215
7.4 Image Functions .......................................... 221
7.4.1 Point-spread function ............................. 222
7.4.2 Line-spread function .............................. 227
7.4.3 Edge-spread function .............................. 227
7.4.4 Optical transfer function ......................... 228
7.4.5 MTF and contrast .................................. 230
7.5 Image Modeling ........................................... 234
7.5.1 Wavefront model ................................... 235
7.5.2 Diffraction ....................................... 237
7.6 Lens MTF ................................................. 241
7.6.1 Resolution ........................................ 251
7.6.2 Image quality ..................................... 255
7.7 Sensor MTF ............................................... 261
7.7.1 Spatial MTF ....................................... 261
7.7.2 Diffusion MTF ..................................... 266
7.7.3 Charge-transfer MTF ............................... 271
References ............................................... 279
Chapter 8 Camera Calibration ................................. 283
8.1 Projection ............................................... 284
8.2 Ideal Intrinsic Model .................................... 289
8.3 Extrinsic Model .......................................... 292
8.3.1 Translation ....................................... 294
8.3.2 Rotation .......................................... 294
8.4 General Camera Model ..................................... 295
8.5 Tsai Calibration ......................................... 298
8.5.1 Camera model ...................................... 298
8.5.2 Scaling and origin transfer ....................... 300
8.5.3 Stage 1 calibration: Parameters embedded in image
abscissa .......................................... 301
8.5.4 Stage 2 calibration: Parameters related to image
ordinate .......................................... 304
8.5.5 Resolution and distortion ......................... 305
8.6 Stereo Imaging ........................................... 311
8.6.1 Epipolar geometry ................................. 313
8.6.2 Matching with epipolar constraints ................ 321
8.7 Feature Matching ......................................... 323
8.7.1 Intensity matching ................................ 323
8.7.2 Cross-correlation ................................. 324
8.7.3 Edge feature ...................................... 326
8.8 Inclined Camera .......................................... 331
8.8.1 Viewing direction ................................. 333
8.8.2 Scaling factors ................................... 333
References ............................................... 336
Chapter 9 Gray-Level Transformation .......................... 341
9.1 Pixel-to-Pixel Mapping ................................... 342
9.2 Gamma Correction ......................................... 343
9.3 Image Histogram .......................................... 345
9.4 Histogram Equalization ................................... 348
9.5 Histogram Hyperbolization ................................ 350
9.6 Histogram Specification .................................. 354
9.7 Local Histogram .......................................... 357
9.8 Statistical Differencing ................................. 357
9.9 Thresholding ............................................. 361
9.9.1 Triangular minimum method ......................... 363
9.9.2 Iterative mean method ............................. 363
9.10 Co-occurrence Matrix ..................................... 365
Appendix 9A: Histogram Properties ............................. 371
9A.1 Definitions .............................................. 371
9A.2 Variate Transformation ................................... 372
References ............................................... 375
Chapter 10 Spatial Transformation ............................. 379
10.1 Interpolation ............................................ 380
10.2 Geometric Operations ..................................... 384
10.2.1 Forward transformation ............................ 387
10.2.2 Вackward transformation ........................... 387
10.2.3 Rescaling Cartesian coordinates ................... 390
10.3 Bilinear Interpolation ................................... 391
10.4 Cubic Interpolation ...................................... 394
10.5 Zero-Order Convolution ................................... 404
10.6 Affine Transformation .................................... 408
10.7 Perspective Transformation ............................... 411
Appendix 10A: Basis Functions and Splines ..................... 419
10A.1 Hermite Curves .......................................... 422
10A.2 Cardinal Splines ........................................ 425
10A.3 Bezier Curves ........................................... 427
10A.4 Cubic Splines ........................................... 435
References ............................................... 441
Chapter 11 Spatial Filtering .................................. 445
11.1 Noise Models ............................................. 447
11.2 Averaging Filters ........................................ 453
11.2.1 Gaussian filter ................................... 455
11.2.2 Rotating average .................................. 456
11.2.3 Sigma filter ...................................... 457
11.2.4 Outlier filter .................................... 458
11.2.5 Unsharp mask ...................................... 458
11.3 Rank-Order Filters ....................................... 459
11.4 Adaptive Filters ......................................... 461
11.4.1 Additive noise .................................... 462
11.4.2 Impulse noise ..................................... 463
11.4.3 Multiplicative noise .............................. 465
11.5 First-Order Gradients .................................... 467
11.5.1 Roberts operator .................................. 469
11.5.2 Prewitt operator .................................. 469
11.5.3 Sobel operator .................................... 471
11.6 Second-Order Gradients ................................... 471
11.7 Anisotropic Filters ...................................... 477
11.7.1 Bilateral filters ................................. 477
11.7.2 Diffusion filters ................................. 478
Appendix 11A: Convolution Kernels ............................. 482
11A.1 Discrete Convolution .................................... 483
11A.2 Two-Dimensional Convolution ............................. 486
References ............................................... 490
Chapter 12 Discrete Fourier Transform ......................... 495
12.1 Discrete Fourier Series .................................. 495
12.2 Discrete Fourier Transform ............................... 501
12.3 Decimation-in-Time FFT ................................... 506
12.4 Image Frequency Spectrum ................................. 515
12.5 Basis Function ........................................... 520
12.6 Matrix Form .............................................. 528
12.6.1 DIT in matrix form ................................ 530
12.6.2 DIF in matrix form ................................ 533
Appendix 12A: DFT Through Decomposition ....................... 535
12A.1 Eight-Point DFT with Radix 2 ............................ 535
12A.2 Decimation in Frequency ................................. 539
12A.3 Mixed Radix ............................................. 541
References ............................................... 544
Chapter 13 Spatial Frequency Filters .......................... 545
13.1 Fourier Series Finite Sum ................................ 547
13.2 DFT Computation .......................................... 551
13.3 Spectrum Display ......................................... 556
13.3.1 Origin shifting ................................... 557
13.3.2 Amplitude scaling ................................. 561
13.3.3 Frequency scaling ................................. 564
13.4 Ideal Filters ............................................ 571
13.5 Butterworth Filter ....................................... 578
13.5.1 Low-pass Butterworth filter ....................... 579
13.5.2 High-pass Butterworth filter ...................... 582
13.6 Gaussian Filter .......................................... 582
13.6.1 Low-pass Gaussian filter .......................... 588
13.6.2 High-pass Gaussian filter ......................... 588
13.7 Homomorphic Filter ....................................... 590
13.8 Image Restoration ........................................ 593
References ............................................... 597
Chapter 14 Review of Image Parameters ......................... 601
14.1 Image Contrast ........................................... 602
14.2 Lens Resolution .......................................... 602
14.3 Sensor Resolution ........................................ 608
14.4 Aliasing ................................................. 612
14.5 Image Display ............................................ 617
14.6 Image Printing ........................................... 624
14.7 File Format .............................................. 630
14.8 Bibliographical Notes .................................... 632
References ............................................... 635
Appendix A Fourier Transformation ............................ 639
A.l Fourier Series ........................................... 639
A.2 Extension to Nonperiodic Wavetrain ....................... 643
A.3 Commonly Used Functions .................................. 646
A.3.1 Rectangular and delta functions ................... 646
A.3.2 Sine function ..................................... 649
A.3.3 Comb function ..................................... 650
A.3.4 Fourier transforms ................................ 650
A.4 2D Fourier Transform ..................................... 657
A.5 Fourier Transform of Images .............................. 659
References ............................................... 664
Appendix В Sampling ........................................... 667
B.l Introduction ............................................. 667
B.2 Frequency Folding ........................................ 671
B.3 Spatial Foldover ......................................... 673
B.4 Reconstruction ........................................... 674
B.5 2D Sampling .............................................. 676
References ............................................... 681
Appendix С Discrete Fourier Transform ......................... 683
References ............................................... 692
Appendix D Time-Frequency Mapping ............................. 693
D.l Laplace Transform ......................................... 693
D.2  Transform ............................................... 695
D.3 Transfer Function ......................................... 698
D.4 Pulse Transfer Function ................................... 699
D.5 Digitization of Transfer Functions ........................ 701
D.6 Analog Filter ............................................. 703
D.7 Digital Filter ............................................ 707
D.8 Frequency Warping ......................................... 712
References ................................................ 715
Index ......................................................... 717
|
