Image Formation Lens Optics Photometry Geometric Optics Prof
- Slides: 10
Image Formation Lens Optics, Photometry, Geometric Optics Prof. Dr. Elli Angelopoulou Chair of Pattern Recognition (Computer Science 5) Friedrich-Alexander-University Erlangen-Nuremberg
Page 2 Thin Lens Center of projection (COP): center of lens Optic axis: axis perpendicular to the lens that passes through the COP Focus of the lens, Fr: point on the optic axis where all the parallel rays incident on the lens converge. Focal length, f: the perpendicular distance between the lens and the focus point of the lens Fr Elli Angelopoulou Image Formation
Page 3 Imaging with Thin Lens From the similar triangles P Fl S and R Fl O => and the similar triangles p Fr s and Q Fl O => But and => Let and . Then Elli Angelopoulou Thin Lens Law Image Formation
Page 4 Lens-related definitions n More definitions: n Effective diameter of a lens, d: diameter of the lens reachable by light rays (an adjustable iris changes the effective diameter of a lens. n Field of view w: the half-angle subtended by the effective lens diameter, d, on the focus, F: n Depth of field: range of depth values that appear in- focus in an image. n F-stop number: the ratio of the focal length over the effective diameter, Elli Angelopoulou Image Formation
Page 5 Light-surface-camera Elli Angelopoulou Image Formation
Page 6 Radiometry n Questions: § how “bright” will surfaces be? § what is “brightness”? § measuring light § interactions between light and surfaces n Core idea - think about light arriving at a surface n Around any point is a hemisphere of directions n Simplest problems can be dealt with by reasoning about this hemisphere Elli Angelopoulou Image Formation
Page 7 Solid Angle Elli Angelopoulou Image Formation
Page 8 Lens and Solid Angles Elli Angelopoulou Image Formation
Page 9 Camera Coords Elli Angelopoulou Image Formation
Page 10 Radial Distortion n A pin-hole image of a square grid. n A lens-system image of the same square grid Image courtesy of VIPBase Elli Angelopoulou Image Formation