Upcoming Deadlines

Homework #13 – Creating Stereoscopic 3D ImagesDue Thursday, December 8th (Next week)20 points (10 points if late)

Final Exam - Thursday, December 15th 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 ExamFinal 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 ExamSample 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 15th 9:45-Noon in this room

Homework #13Creating 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 #13Upload 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 8th -- 20 points (10 points if late)

Survey QuestionFrom which of these assignments did

you learn the most:A) Term paperB) Homeworks using TrackerC) Stop-motion animation homeworksD) Homeworks using MayaE) Other (reverse reference, etc.)

Review QuestionWhich path does

light ray take after entering the water?

A) Path AB) Path BC) Path CD) Path D

D

CBA

Law of Refraction

C) Path CAngle is smaller in the denser material.

The light ray bends but does not cross the normal (line perpendicular to the surface)

Review QuestionNatural 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 ReflectionTrue. For the same reason you can only see the sky from underwater when looking up at more than about a 45 degree angle.

See skyMirror

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 from400 nanometers (blue) to 700 nanometers (red).

Demo: SpectrometerSpectrometer 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 WheelPrism 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

SpectralColors

There are No

Photons of These Colors

R

Y

B G

M

C

RedYellowGreenCyanBlueMagenta

Adding Color LightsStream of red & green photons looks same as yellow photons(metamerism)

Theatrical lighting

or

YELLO

W

Eye toBrain

Notice overlap of red, green, & blue is seen as white light

Simple Trichromatic TheoryYellow &

Redphotons

excite me

Yellow, Green &

Cyanphotons

excite me

Cyan &Blue

photons excite me

Imagine that inside your eye are these three guys, who send messages to your brain.

BIFFGREGRONRON

GREG

BIFF

Trichromatic: Seeing Yellow

Yellow &Red

photons excite me.

I’M EXCITED

Yellow, Green &Cyan photons

excite me.I’M EXCITED

Cyan & Bluephotons

excite me.Yawn.

Yellow seen when Ron and Greg are excited, either by yellow photons or red & green photons.

OR

RON

GREG

BIFF

Seeing YellowSodium 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

Use Spectrometer

Use Spectrometer

The Ear vs. The Eye

AE 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 & Bluephotons

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 DiskDisk painted half red, half blue looks

magenta when rapidly spinning.

Use Spectrometer

Use Spectrometer

Use Spectrometer

Trichromatic: Two is Not Enough

Blue & Greenphotons excite

me.I’M EXCITED

Green & Redphotons excite

me.I’M EXCITED

OR

With only two receptors Green and Magenta look the same.

Mixing Blue & Red PaintMixing paint or ink is different from

adding colors together by light.

Mix of blue and red paint produces a blackish brown

Trichromatic: Seeing White

Yellow &Red

photons excite me.

I’M EXCITED

Yellow, Green &Cyan photons

excite me.I’M EXCITED

Cyan & Bluephotons

excite me.I’M EXCITED

White seen when all three are very excited;Gray seen when all three less excited

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

Use Spectrometer

Use Spectrometer

Use Spectrometer

Use Spectrometer

Value (Brightness)I’m a little

excitedYawn. Yawn.The level of

excitement indicates the value of a color, which is sometimes called the brightness.

Yawn.Yawn.I’M VERY EXCITED!

Dim Red Light

Bright Red Light

Saturation

I’m a little excited

Yawn. 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!

SaturatedColor

UnsaturatedColor

Hue, Saturation, ValueColor wheel is nota single wheel butstack of wheels that range invalue.

Hue Value

Saturation

Photoshop Color Picker

Saturation

ValueHue

Saturation & Value

High Value andLow Saturation

Low Value andHigh Saturation

As lighting conditions change, value and saturation usually vary together.

Value Saturation

Value

Saturation

Trichromatic: Color BlindnessRed , Yellow,

Green &Cyan photons

excite me.I’M EXCITED

Cyan & Bluephotons

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 BlindnessClassification

Incidence (%)Males Females

AnomalousTrichromacy 6.3 0.37

Protanomaly(Red-cone weak) 1.3 0.02

Deuteranomaly(Green-cone weak) 5.0 0.35

Tritanomaly(Blue-cone weak) 0.0001 0.0001

Dichromacy 2.4 0.03 Protanopia

(Red-cone absent) 1.3 0.02

Deuteranopia(Green-cone absent) 1.2 0.01

Tritanopia(Blue-cone absent) 0.001 0.03

Rod Monochromacy(no cones) 0.00001 0.00001

29 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, 1904-5

Color and Value

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

Color and Value

Color and Value

Trichromatic: After-Image

First stare at RED

I’M EXCITED!

Yawn. Yawn.

Would be excited,

but tired.Then stare at WHITE

Only Greg and Biff are excited; what color is seen?A) YellowB) Magenta C) CyanD) Orange

I’M EXCITED!

I’M EXCITED!

Trichromatic theory also explains seeing after-images.

Trichromatic: After-Image

First stare at RED

I’M EXCITED!

Yawn. Yawn.

Then stare at WHITE

Only Greg and Biff are excited; what color is seen?

A) YellowB) Magenta C) CyanD) Orange

I’M EXCITED!

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: OpponencyYellow &

Redphotons

excite me. I’M EXCITED

Yellow, Green &Cyan photons

excite me.I’M EXCITED

Oh, Shut The F*@%

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 EyeThree types of cones (color)One type of rod (B/W only)

Human Color VisionThe 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 TriangleJ.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 perfectoptical instrument.

Color “wheel” isactually distortedcone shape.

Rim is full saturation,center is white

Ron %

Gre

g %

50% Ron50% Greg0% Biff

33% Ron33% Greg33% Biff

Gamut of ColorOuter “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 Lecture3D stereoscopic

imaging

Please return the spectrometers & clickers!