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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 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 15th 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 8th -- 20 points (10 points if late)
Survey Question
From 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 Question
Which 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 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 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: 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
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
YELL
OW
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 Disk
Disk 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 Paint
Mixing 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 Disk
Disk 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 excited
Yawn. 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, Value
Color wheel is nota single wheel butstack of wheels that range invalue.
HueValue
Saturation
Photoshop Color Picker
Saturation
Valu
e
Hue
Saturation & Value
High Value andLow Saturation
Low Value andHigh Saturation
As lighting conditions change, value and saturation usually vary together.
Valu
e
Saturation
Valu
e
Saturation
Trichromatic: Color Blindness
Red , 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 Blindness
Classification
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 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 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 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 Lecture3D stereoscopic
imaging
Please return the spectrometers & clickers!