Librería Portfolio

Appropriate for upper-division undergraduate- and graduate-level courses in computer vision found in departments of Computer Science, Computer Engineering and Electrical Engineering.

This textbook provides the most complete treatment of modern computer vision methods by two of the leading authorities in the field. This accessible presentation gives both a general view of the entire computer vision enterprise and also offers sufficient detail for students to be able to build useful applications. Students will learn techniques that have proven to be useful by first-hand experience and a wide range of mathematical methods.



I IMAGE FORMATION 1
1 Geometric Camera Models 3
1.1 Image Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1.1 Pinhole Perspective . . . . . . . . . . . . . . . . . . . . . . . 4
1.1.2 Weak Perspective . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.1.3 Cameras with Lenses . . . . . . . . . . . . . . . . . . . . . . . 8
1.1.4 The Human Eye . . . . . . . . . . . . . . . . . . . . . . . . . 12
1.2 Intrinsic and Extrinsic Parameters . . . . . . . . . . . . . . . . . . . 14
1.2.1 Rigid Transformations and Homogeneous Coordinates . . . . 14
1.2.2 Intrinsic Parameters . . . . . . . . . . . . . . . . . . . . . . . 16
1.2.3 Extrinsic Parameters . . . . . . . . . . . . . . . . . . . . . . . 18
1.2.4 Perspective Projection Matrices . . . . . . . . . . . . . . . . . 19
1.2.5 Weak-Perspective Projection Matrices . . . . . . . . . . . . . 20
1.3 Geometric Camera Calibration . . . . . . . . . . . . . . . . . . . . . 22
1.3.1 ALinear Approach to Camera Calibration . . . . . . . . . . . 23
1.3.2 ANonlinear Approach to Camera Calibration . . . . . . . . . 27
1.4 Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
2 Light and Shading 32
2.1 Modelling Pixel Brightness . . . . . . . . . . . . . . . . . . . . . . . 32
2.1.1 Reflection at Surfaces . . . . . . . . . . . . . . . . . . . . . . 33
2.1.2 Sources and Their Effects . . . . . . . . . . . . . . . . . . . . 34
2.1.3 The Lambertian+Specular Model . . . . . . . . . . . . . . . . 36
2.1.4 Area Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
2.2 Inference from Shading . . . . . . . . . . . . . . . . . . . . . . . . . . 37
2.2.1 Radiometric Calibration and High Dynamic Range Images . . 38
2.2.2 The Shape of Specularities . . . . . . . . . . . . . . . . . . . 40
2.2.3 Inferring Lightness and Illumination . . . . . . . . . . . . . . 43
2.2.4 Photometric Stereo: Shape from Multiple Shaded Images . . 46
2.3 Modelling Interreflection . . . . . . . . . . . . . . . . . . . . . . . . . 52
2.3.1 The Illumination at a Patch Due to an Area Source . . . . . 52
2.3.2 Radiosity and Exitance . . . . . . . . . . . . . . . . . . . . . 54
2.3.3 An Interreflection Model . . . . . . . . . . . . . . . . . . . . . 55
2.3.4 Qualitative Properties of Interreflections . . . . . . . . . . . . 56
2.4 Shape from One Shaded Image . . . . . . . . . . . . . . . . . . . . . 59
2.5 Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
3 Color 68
3.1 Human Color Perception . . . . . . . . . . . . . . . . . . . . . . . . . 68
3.1.1 Color Matching . . . . . . . . . . . . . . . . . . . . . . . . . . 68
3.1.2 Color Receptors . . . . . . . . . . . . . . . . . . . . . . . . . 71
3.2 The Physics of Color . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
3.2.1 The Color of Light Sources . . . . . . . . . . . . . . . . . . . 73
3.2.2 The Color of Surfaces . . . . . . . . . . . . . . . . . . . . . . 76
3.3 Representing Color . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
3.3.1 Linear Color Spaces . . . . . . . . . . . . . . . . . . . . . . . 77
3.3.2 Non-linear Color Spaces . . . . . . . . . . . . . . . . . . . . . 83
3.4 AModel of Image Color . . . . . . . . . . . . . . . . . . . . . . . . . 86
3.4.1 The Diffuse Term . . . . . . . . . . . . . . . . . . . . . . . . . 88
3.4.2 The Specular Term . . . . . . . . . . . . . . . . . . . . . . . . 90
3.5 Inference from Color . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
3.5.1 Finding Specularities Using Color . . . . . . . . . . . . . . . 90
3.5.2 Shadow Removal Using Color . . . . . . . . . . . . . . . . . . 92
3.5.3 Color Constancy: Surface Color from Image Color . . . . . . 95
3.6 Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
II EARLY VISION: JUST ONE IMAGE 105
4 Linear Filters 107
4.1 Linear Filters and Convolution . . . . . . . . . . . . . . . . . . . . . 107
4.1.1 Convolution . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
4.2 Shift Invariant Linear Systems . . . . . . . . . . . . . . . . . . . . . 112
4.2.1 Discrete Convolution . . . . . . . . . . . . . . . . . . . . . . . 113
4.2.2 Continuous Convolution . . . . . . . . . . . . . . . . . . . . . 115
4.2.3 Edge Effects in Discrete Convolutions . . . . . . . . . . . . . 118
4.3 Spatial Frequency and Fourier Transforms . . . . . . . . . . . . . . . 118
4.3.1 Fourier Transforms . . . . . . . . . . . . . . . . . . . . . . . . 119
4.4 Sampling and Aliasing . . . . . . . . . . . . . . . . . . . . . . . . . . 121
4.4.1 Sampling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
4.4.2 Aliasing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
4.4.3 Smoothing and Resampling . . . . . . . . . . . . . . . . . . . 126
4.5 Filters as Templates . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
4.5.1 Convolution as a Dot Product . . . . . . . . . . . . . . . . . 131
4.5.2 Changing Basis . . . . . . . . . . . . . . . . . . . . . . . . . . 132
4.6 Technique: Normalized Correlation and Finding Patterns . . . . . . 132
4.6.1 Controlling the Television by Finding Hands by Normalized
Correlation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
4.7 Technique: Scale and Image Pyramids . . . . . . . . . . . . . . . . . 134
4.7.1 The Gaussian Pyramid . . . . . . . . . . . . . . . . . . . . . 135
4.7.2 Applications of Scaled Representations . . . . . . . . . . . . . 136
4.8 Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137
5 Local Image Features 141
5.1 Computing the Image Gradient . . . . . . . . . . . . . . . . . . . . . 141
5.1.1 Derivative of Gaussian Filters . . . . . . . . . . . . . . . . . . 142
5.2 Representing the Image Gradient . . . . . . . . . . . . . . . . . . . . 144
5.2.1 Gradient-Based Edge Detectors . . . . . . . . . . . . . . . . . 145
5.2.2 Orientations . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147
5.3 Finding Corners and Building Neighborhoods . . . . . . . . . . . . . 148
5.3.1 Finding Corners . . . . . . . . . . . . . . . . . . . . . . . . . 149
5.3.2 Using Scale and Orientation to Build a Neighborhood . . . . 151
5.4 Describing Neighborhoods with SIFT and HOG Features . . . . . . 155
5.4.1 SIFT Features . . . . . .