Presentation on theme: "Upcoming Classes Tuesday, Nov. 13 th Lenses and the Eye Assignment due: Homework #6 (Grid Drawing) Thursday, Nov. 15 th Optics and Photography Special."— Presentation transcript:
Upcoming Classes Tuesday, Nov. 13 th Lenses and the Eye Assignment due: Homework #6 (Grid Drawing) Thursday, Nov. 15 th Optics and Photography Special Guest: Prof. Brian Taylor, Photography, SJSU Assignment due: * Read “The Camera and Photograph, Seeing the Light : Optics in Nature, Photography, Color, Vision, and Holography, D. Falk, D. Brill, & D. Stork, Pages 107-117
Upcoming Deadlines Tuesday, November 15 th Outline of third oral presentation or written paper Tuesday, December 4 th Third Set of Oral Presentations Third term paper (if not presenting)
Oral Presentations (III) The following persons will give oral presentations on Tuesday, December 4 th : Remmel, Katherine Sugiura, Ayuka Yamaguchi, Asuka Zeber, Emily, Dinh, Phiphi For everyone else, term paper is due on that date.
Homework 5: Exploratorium Due Thursday, November 29 th
Extra Credit: Beethoven Center Visit the Beethoven Center on the Fifth floor of MLK library. Take a photo of yourself with one of the pianos or harpsichords. Turn in photo by Thurs., Nov. 15 th for one quiz worth of extra credit.
Extra Credit: San Jose Ballet See a performance of San Jose Ballet in San Jose Center for Performing Arts (Nov. 15 th – 18 th ). Turn in your ticket receipt. Worth one homework assignment or three quiz/participation credits. Ramon Moreno in CARMINA BURANA
Quiz Today’s reading was on a controversial theory proposed by the painter David Hockney regarding this painting by Van Eyck. Briefly, what is Hockney’s claim?
Ray Tracing Geometric optics is the tracing the path taken by light rays. Tracing light rays through lenses St Joseph the Carpenter, Georges de La Tour, (1654) Analysis of cast shadows using ray tracing
Computer Ray Tracing Ray tracing requires geometric calculations, which are easily done by computer. Image created by POV-Ray, a public-domain ray tracing program Tracing light rays from light source to object to eye Light source Object Computer Monitor
Shadows Size and sharpness of a shadow depends on size and distance of light source and of object casting the shadow.
Ray Tracing for Shadows Trace rays from light source to wall to map out location of deep shadow (umbra) and fuzzy shadow (penumbra). UMBRA Penumbra Light source Object Wall
Inconsistent Shadows The perspective in this painting is pretty good but what’s wrong with the shadows? The Birth of the Virgin Fra Carnevale, 1467
Inconsistent Shadows The Birth of the Virgin Fra Carnevale, 1467 Long shadows from left to right No shadows? Rising shadows? Downward shadow?
Specular and Diffuse Reflection Reflection from most surfaces is diffuse, with incoming light scattered in all directions. Reflection from mirror surfaces is specular, with light reflecting in one direction. Mirror Diffuse reflection Specular reflection
Check Yourself What objects in this room radiate light? Every object with a temperature radiates so every object in this room radiates, mostly infrared light, outside the visible range. Is the projector screen radiating visible light? No, it is reflecting light from projector lamp. Is the screen diffuse or specular reflector? Diffuse, so that everyone in the room can see what is projected onto the screen.
Diffuse Surface is Not a Mirror Light rays diffusely scatter in every direction from every spot on the surface. See a light ray from the top of your head reflected from this spot. Also see light ray from the tip of your nose reflected from this spot. Look at this spot on a diffuse surface
Transparent, Reflecting Surfaces Water and glass are transparent but reflect some of the light striking their surface. Can see inside the cab through the right window. Strong reflection of the sun on the left window. Can see some of the riverbed through the water surface.
One Way Mirror One way mirror is just clear glass window. Bright Room Dark Room Discussion Room (Bright) Observation Room (Dark) GLASS Reflected light from bright room masks transmitted light from the darkened observation room
Law of Reflection Angle of incidence equals angle of reflection SPECULAR REFLECTION
Ray Tracing Light ray from point A is reflected at point B and arrives at point B. Notice the relationship between point B (where the ray is reflected to) and point B’ (where the ray would go if the mirror wasn’t there).
Demo: Who Do You See? Which person in the front row sees the guy with the hat (person F) in the mirror? Person B sees person F (with hat). F Diffuse light ABC DEG MIRROR
Mirror Image Reflection To observer at point B, the light from point A seems to come from point A’, within mirror.
Plane (Flat) Mirror Tracing light rays from original, to mirror, to eye allows us to construct image. Original Image Mirror HAIR NOSE CHIN
Demo: Pocket Mirror See full image of your head in a plane mirror that’s half the size of your head. Original Image Mirror
Image in the Mirror Utamaro, Woman Powdering Her Neck Velazquez, Venus at her Mirror Helmut Newton, Bergstrom over Paris Image is seen an equal distance from original within a plane mirror. Incorrect Correct
Non-Flat Mirrors Image in a curved mirror is distorted from original. Determine image location and size by ray tracing
Demo: Convex Mirrors Mirrored surface on a sphere or similar rounded shape. Image is smaller & closer. MC Escher Hand with Reflecting Sphere
Ray Tracing for Convex Mirror Image in convex mirror is smaller & closer. Original Image Mirror
Image in the Mirror #2 Portrait of Giovanni Arnolfini and his Wife (1434) by Hubert and Jan van EYCK
Demo: Concave Mirrors Mirror is on the inner curved surface of sphere or similar rounded shape. Image size and location depends on object’s distance from the mirror. Telescope
Ray Tracing for Concave Mirror Image in concave mirror is larger when original is close to the mirror. Original Image Mirror The original is closer to the mirror than the focal point. Focal Point
Image Ray Tracing for Concave Mirror Image in a concave mirror is inverted if the original is far away from the mirror. Image is formed in front of the mirror, not within it. Original Mirror Focal Point
Demo: Forming a Real Image Locate the image formed in front of a concave mirror using a strong light source and a screen. Candle Image Screen
Arnolfini Portrait Could van Eyck have used a concave mirror to help him create his masterpiece? Theoretically yes, but detailed analysis indicates he probably did not.
Next Lecture Lenses and the Eye Remember: Assignment due: Homework 6 (Grid drawing)