Upcoming Deadlines Homework #13 – Creating Stereoscopic 3D Images Due Thursday, December 8 th (Next week) 20 points (10 points if late) Final Exam - Thursday, December 15 th 9:45AM-12:00 Noon in this room. For full schedule, visit course website: ArtPhysics123.pbworks.com Please take a clicker and a spectroscope

Final Exam Final Exam will have 10 short essay questions on material covered in lecture. Final exam counts for 50 points. See course website for copy of last semester’s final exam. You may bring one page of notes double- sided (or two pages single-sided) to the exam.

Final Exam Sample Questions: * What is “drag” in animation? Give an example to illustrate your definition. What physics principle causes “drag” to occur? * Explain the difference between reflection and refraction. Also give two examples of each. Final Exam is on: Thursday, December 15 th 9:45-Noon in this room

Homework #13 Creating stereoscopic 3D images. For this assignment you will create at least three different stereoscopic images from photographs. At least one of the images should have you appearing in the photo and at least one of the images should be of a recognizable location on campus. You will be graded on the composition so plan your scenes to make them interesting (especially for 3D).

Stereo 3D Photos with PhotoShop Steps for creating stereo 3D photos in PhotoShop: 1)Snap a photo, move 3 inches to the right, take a second photo. Avoid having objects closer than a yard away from the camera and no moving objects! 2)Open both images in PhotoShop. Hold the shift key and drag the right eye image on to left eye image. 3)Rename the layers “Right Eye” and “Left Eye”; make sure the Right Eye layer is on top. 4)Double click the Right Eye thumbnail to open the Blending Window. In Advanced Blending uncheck the Red Channel for Red/Cyan glasses (or Green Channel for Green/Magenta glasses).

Stereo 3D Photos with PhotoShop Uncheck the Red Channel Select Right Eye Layer

Homework #13 Upload your photos to your blog in an entry entitled “Creating Stereoscopic 3D Images” Optional: You can also create a pair of stereo-ready images in Autodesk Maya by rendering a scene for one image, then shifting the camera position and rendering the second image. Bonus Points: Create a 3D animated short, either by stop motion or in Maya. Ten bonus points for a good animation; twenty bonus points for a great one. Due Thur., December 8 th points (10 points if late)

Survey Question From which of these assignments did you learn the most: A)Term paper B)Homeworks using Tracker C)Stop-motion animation homeworks D)Homeworks using Maya E)Other (reverse reference, etc.)

Review Question Which path does light ray take after entering the water? A) Path A B) Path B C) Path C D) Path D D C B A

Law of Refraction C) Path C Angle is smaller in the denser material. The light ray bends but does not cross the normal (line perpendicular to the surface)

Review Question Natural lighting underwater is primarily from overhead because sunlight cannot enter the water at more than about a 45 degree angle. True or False?

Total Internal Reflection True. For the same reason you can only see the sky from underwater when looking up at more than about a 45 degree angle. See sky Mirror

Seeing Color

Spectrum of Visible Light

Wavelengths & Photons Red Photon Blue Photon Green Photon Yellow Photon Particles of light, called photons, each have a wavelength that determines the color we see for that photon. Visible light is roughly from 400 nanometers (blue) to 700 nanometers (red).

Demo: Spectrometer Spectrometer separates the wavelengths of light, creating a rainbow that shows you the intensity in each hue (color). Light bulb Spectrum  Long Wavelength Short 

Use Spectrometer

Newton’s Color Wheel Prism spectrum is a straight line, so why did Isaac Newton describe color using a circular wheel? This segment is added to join the two ends of the spectrum

Additive Color Wheel Spectral Colors There are No Photons of These Colors R Y B G M C Red Yellow Green Cyan Blue Magenta

Adding Color Lights Stream of red & green photons looks same as yellow photons (metamerism) Theatrical lighting or YELLOW Eye to Brain white Notice overlap of red, green, & blue is seen as white light

Simple Trichromatic Theory Yellow & Red photons excite me Yellow, Green & Cyan photons excite me Cyan & Blue photons excite me Imagine that inside your eye are these three guys, who send messages to your brain. BIFF GREG RON GREG BIFF

Yellow Trichromatic: Seeing Yellow Yellow & Red photons excite me. I’M EXCITED Yellow, Green & Cyan photons excite me. I’M EXCITED Cyan & Blue photons excite me. Yawn. Yellow seen when Ron and Greg are excited, either by yellow photons or red & green photons. OR RON GREG BIFF

Seeing Yellow Sodium lamps emit near pure yellow photons Color monitor can only emit red, green, and blue (RGB); creates other colors by selectively turning RGB pixels on or off. “Electric pickle” is also a sodium light

Use Spectrometer

The Ear vs. The Eye A E D How the ear senses sound waves is distinct from how the eye senses light waves. Hearing an E and a D together does not sound like an A. Seeing green and red together does look like yellow light.

Trichromatic: Seeing Magenta Yellow & Red photons excite me. I’M EXCITED Yellow, Green & Cyan photons excite me. Yawn. Cyan & Blue photons excite me. I’M EXCITED Magenta is seen by eye when Ron and Biff are excited, which no single type of photon can achieve. RON GREG BIFF

Maxwell Color Disk Disk painted half red, half blue looks magenta when rapidly spinning.

Use Spectrometer

Trichromatic: Two is Not Enough Blue & Green photons excite me. I’M EXCITED Green & Red photons excite me. I’M EXCITED OR With only two receptors Green and Magenta look the same.

Mixing Blue & Red Paint Mixing paint or ink is different from adding colors together by light. Mix of blue and red paint produces a blackish brown

White Trichromatic: Seeing White Yellow & Red photons excite me. I’M EXCITED Yellow, Green & Cyan photons excite me. I’M EXCITED Cyan & Blue photons excite me. I’M EXCITED White seen when all three are very excited; Gray seen when all three less excited

Maxwell Color Disk Disk with blue, green, and red filters looks grayish white when rapidly spinning.

Use Spectrometer

Value (Brightness) I’m a little excited Yawn. The level of excitement indicates the value of a color, which is sometimes called the brightness. Yawn. I’M VERY EXCITED! Dim Red Light Bright Red Light

Saturation I’m a little excited Yawn. When white light is mixed in with a pure color the eye sees the sum as being less saturated. Saturation also called chroma. I’M VERY EXCITED! Pure Red Light Pink Light I’m a little excited I’M VERY EXCITED! Saturated Color Unsaturated Color

Hue, Saturation, Value Color wheel is not a single wheel but stack of wheels that range in value. Hue Value Saturation

Photoshop Color Picker Saturation Value Hue

Saturation & Value High Value and Low Saturation Low Value and High Saturation As lighting conditions change, value and saturation usually vary together. Value Saturation Value Saturation

Trichromatic: Color Blindness Red, Yellow, Green & Cyan photons excite me. I’M EXCITED Cyan & Blue photons excite me. Yawn. Color blindness occurs if the eye is missing one of the three receptors. The other receptors try to compensate but cannot distinguish some colors. Do I see red or green? OR

Color Blindness Classification Incidence (%) MalesFemales Anomalous Trichromacy Protanomaly (Red-cone weak) Deuteranomaly (Green-cone weak) Tritanomaly (Blue-cone weak) Dichromacy Protanopia (Red-cone absent) Deuteranopia (Green-cone absent) Tritanopia (Blue-cone absent) Rod Monochromacy (no cones) or 70? 21 or 74? Weakness or absence of one of the three types of cones is the cause of color blindness, leading to a reduced ability to distinguish colors.

Color and Value Henri Matisse, Woman With Hat,

Color and Value Which of these two versions looks better to you? (SQUINT)

Color and Value

Trichromatic: After-Image First stare at RED I’M EXCITED! Yawn. Would be excited, but tired. Then stare at WHITE Only Greg and Biff are excited; what color is seen? A)Yellow B)Magenta C) Cyan D) Orange I’M EXCITED! Trichromatic theory also explains seeing after-images.

Trichromatic: After-Image First stare at RED I’M EXCITED! Yawn. Then stare at WHITE Only Greg and Biff are excited; what color is seen? A)Yellow B)Magenta C) Cyan D) Orange I’M EXCITED! Trichromatic theory also explains seeing after-images. Would be excited, but tired.

Negative After-image Stare, unfocused, at the red cross for 10 seconds then look at white wall

Negative After-image Cyan

Negative After-image Stare, unfocused, at the flag for 10 seconds then look at white wall

Negative After-image Cyan Magenta Yellow

Negative After-image From Practical Light and Color X

Negative After-image

Trichromatic: Opponency Yellow & Red photons excite me. I’M EXCITED Yellow, Green & Cyan photons excite me. I’M EXCITED Oh, Shut The Up! Yellow seen when Greg and Roy are excited, which can annoy Biff, who then opposes them. Shine Red & Green photons (or Yellow photons)

Simultaneous Contrast The bright yellow background makes the green circle look slightly darker and bluer. The green circles are identical in hue, saturation, and value. That is, they’re exactly the same color. The dark cyan background makes the green circle look slightly lighter and yellower.

Simultaneous Contrast The bright yellow background makes the green circle look slightly darker and bluer. The green circles are identical in hue, saturation, and value. That is, they’re exactly the same color. The dark cyan background makes the green circle look slightly lighter and yellower.

Color Vision in the Eye Three types of cones (color) One type of rod (B/W only)

Human Color Vision The human eye is not a perfect optical instrument so attempts to create color systems with geometrically perfect wheels or triangles are misguided.

Maxwell’s Color Triangle J.C. Maxwell formulated the trichromatic theory for colors in terms of a color triangle. But this construction is not accurate.

CIE Hue-Saturation Diagram Eye is not a perfect optical instrument. Color “wheel” is actually distorted cone shape. Rim is full saturation, center is white Ron % Greg % 50% Ron 50% Greg 0% Biff 33% Ron 33% Greg 33% Biff

Gamut of Color Outer “horseshoe” shape is the gamut of colors which the human eye can distinguish. Inner triangle is the gamut of colors that may be created using just three spectral wavelengths.

Why is Orange Special? Peak sensitivities of green and red cone are close together, so we easily separate colors in this range. The human eye evolved this way to spot ripe fruit and … La Victoria Hot Sauce

Next Lecture 3D stereoscopic imaging Please return the spectrometers & clickers!