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From last time …. Rodrigues’ formula. Beautiful! Toss Euler angles, Y-P-R, quaternions etc. Check Matlab code in laboratory exercises. Homogeneous representation. Points Vectors Transformation representation. Exponential coordinates for rigid body motions.
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From last time … UCLA Vision Lab
Rodrigues’ formula • Beautiful! • Toss Euler angles, Y-P-R, quaternions etc. • Check Matlab code in laboratory exercises UCLA Vision Lab
Homogeneous representation • Points • Vectors • Transformation • representation UCLA Vision Lab
Exponential coordinates for rigid body motions UCLA Vision Lab
Rodrigues’ formula for rigid body motion UCLA Vision Lab
Summary UCLA Vision Lab
Lecture 4: Image formation UCLA Vision Lab
Image formation (Chapter 3) UCLA Vision Lab
Representation of images UCLA Vision Lab
Lenses UCLA Vision Lab
Pinhole model UCLA Vision Lab
Forward pinhole UCLA Vision Lab
Lambertian reflection • Radiance is independent of viewpoint UCLA Vision Lab
Preview of coming attractions • How to go from measurements of light to estimates of geometric primitives? UCLA Vision Lab
Geometric image formation • Coordinate transformations between camera frame and world frame • Perspective projection from 3D to 2D • Coordinate transformation in image coordinate frame UCLA Vision Lab
Ideal geometric camera UCLA Vision Lab
Ideal geometric camera (contd.) UCLA Vision Lab
Intrinsic parameters UCLA Vision Lab
Intrinsic parameters (contd.) • Skew pixels • Overall intrinsic parameter matrix UCLA Vision Lab
CAMERA PARAMETERS – Radial Distortion Nonlinear transformation along the radial direction Distortion correction: make lines straight UCLA Vision Lab
Radial distortion • Will assume compensated (Tsai ’86) see Intel OpenCV in lab assignment UCLA Vision Lab
Overall projection model UCLA Vision Lab
Overall projection model (contd.) UCLA Vision Lab
Calibrated vs. non-calibrated camera UCLA Vision Lab
IMAGE FORMATION – Image of a Point Homogeneous coordinates of a 3-D point Homogeneous coordinates of its 2-D image Projection of a 3-D point to an image plane UCLA Vision Lab
NOTATION – Image, Coimage, Preimage of a Point Image of a 3-D point Coimage of the point Preimage of the point UCLA Vision Lab
NOTATION – Image, Coimage, Preimage of a Line Coimage of a 3-D line Preimage of the line Image of the line UCLA Vision Lab
IMAGE FORMATION – Coimage of a Line Homogeneous representation of a 3-D line Homogeneous representation of its 2-D coimage Projection of a 3-D line to an image plane UCLA Vision Lab
IMAGE FORMATION – Multiple Images “Preimages” are all incident at the corresponding features. . . . UCLA Vision Lab
SUMMARY UCLA Vision Lab
3D EUCLIDEAN SPACE - Cartesian Coordinate Frame Coordinates of a point in space: Standard base vectors: UCLA Vision Lab
3D EUCLIDEAN SPACE - Vectors A “free” vector is defined by a pair of points : Coordinates of the vector : UCLA Vision Lab
3D EUCLIDEAN SPACE – Inner Product and Cross Product Inner product between two vectors: Cross product between two vectors: UCLA Vision Lab
RIGID-BODY MOTION – Rotation Rotation matrix: Coordinates are related by: UCLA Vision Lab
RIGID-BODY MOTION – Rotation and Translation Coordinates are related by: UCLA Vision Lab
RIGID-BODY MOTION – Homogeneous Coordinates 3D coordinates are related by: Homogeneous coordinates are related by: Homogeneous coordinates of a vector: UCLA Vision Lab
IMAGE FORMATION – Lens, Light, and Surfaces image irradiance surface radiance BRDF Lambertian thin lens small FOV UCLA Vision Lab
IMAGE FORMATION – Pinhole Camera Model Pinhole Frontal pinhole UCLA Vision Lab
IMAGE FORMATION – Pinhole Camera Model 2D coordinates Homogeneous coordinates UCLA Vision Lab
CAMERA PARAMETERS – Pixel Coordinates calibrated coordinates Linear transformation pixel coordinates UCLA Vision Lab
CAMERA PARAMETERS – Calibration Matrix and Camera Model Ideal pinhole Pixel coordinates Calibration matrix (intrinsic parameters) Projection matrix Camera model UCLA Vision Lab