Lights, Surfaces, and Cameras. Light sources emit photons Surfaces reflect & absorb photons Cameras measure photons
|
|
- Gillian Briggs
- 5 years ago
- Views:
Transcription
1 Reflectance 1
2 Lights, Surfaces, and Cameras Light sources emit photons Surfaces reflect & absorb photons Cameras measure photons 2
3 Light at Surfaces Many effects when light strikes a surface -- could be: Absorbed, reflected, scattered, and travel along the surface and leave at some other points 3
4 Reflectance Reflectance is all about the way light interacts with surfaces It is an entire field of study on its own The most important quantity is the BRDF 4
5 The BRDF Assumption: No fluoresce, light emission All the light leaving a point depends ONLY on the light arriving at that point ω o n ω i ρ ( ω ) o, ω i Bi-directional Reflectance Distribution Function (BRDF) 5
6 6 Fluorescence
7 The BRDF Given the incoming ray, it describes how reflected lights are distributed This distribution changes when the incoming ray changes 7 plot a BRDF as a function of ω o for a fixed ω i ; the radius along each direction is set to the radiance of the reflected light at that direction.
8 Questions? 8
9 Rendering Equation ω i θ ω r ω o 9 L Reflected Radiance (Pixel Intensity) o ( ωo) = ρbd ( ωo, ωi, ) Li ( ωi) cosθi BRDF Incident Cosine of radiance Incident angle (from light source)
10 Rendering Equation θ ω r 10 L Reflected Radiance (Pixel Intensity) o Sum over all light sources ( ω ) ρ ( ω, ω,) L ( ω ) o = i bd BRDF o i i i cosθ Incident Cosine of radiance Incident angle (from light source) i
11 Rendering Equation dω i θ ω r 11 L Reflected Radiance (Pixel Intensity) o Replace sum with integral ( ω ) o ρbd ( ωo, ωi, ) Li ( ωi) = cosθidωi Ω BRDF Incident radiance (from light source) Cosine of Incident angle
12 Radiometric Image Analysis illumination reflectance shape the rendering equation: determine pixel values from shape, lighting, or reflectance the radiometric image analysis: recover shape, lighting, or reflectance from intensity values 12
13 Radiometric Image Analysis Typical simplification assumptions: Single point light source No inter-reflection Simplified BRDF models (more details later) ω i θ ω r ω o L o ( ωo) = ρbd ( ωo, ωi, ) Li ( ωi) cosθi 13
14 Questions? 14
15 Diffuse & Specular Reflection Diffuse reflection: The surface look the same from all directions (many vision algorithms depend on this!) Matte surfaces Specular reflection: The surface look different from different directions (causes troubles to many vision algorithms) Shiny surfaces ideal diffuse reflection (e.g. walls) 15 ideal specular reflection (e.g. mirror) specular reflection (e.g. plastic, metal, porcelain)
16 Diffuse & Specular Reflection Diffuse reflection: has the same color as the object surface is unpolarized Specular reflection: has the same color as the light source has the same polarization as the light source 16 the original image diffuse reflection specular reflection
17 Questions? 17
18 Common BRDF Models Torrance-Sparrow Lambert s Model 18
19 Lambert s Model Empirical mathematic model for diffuse reflection Assume the BRDF is a constant ρ ( ω, o ωi) = ρ Observed Pixel intensity should be L o = L ρ cosθ = L ρν L i Features of this model: Named after Johann H. Lambert A pixel s brightness does not depend on viewing direction Brightness does depend on direction of illumination This is the model most commonly used in computer vision i i 19 Ν, L, V are unit vectors L, i L o are intensity of incoming and outgoing light
20 Lambert s Model plot a BRDF as a function of ω o for a fixed ω i 20
21 Questions? 21
22 Phong Model Mathematic model for specular reflection Assume light is concentrated on the mirrored direction Intensity of light falls off by cosine law Observed Pixel intensity should be Features of this model: Named after Bui Tuong Phong A pixel s brightness depends on viewing direction This is an empirical model, not physically correct! (e.g. violate energy conservation) 22 L = ( V R) R r L i = 2 n ( N L) N L
23 Phong Model Shininess n controls the size of the highlight spot n cos σ n=1 n=2 n=3 n=
24 Phong Model Linear combination of Lambert s model and Phong Model L = k Ν L + k V R k s 0.1 o d s ( ) n n = 3.0 n = 5. 0 n =10. 0 n = n =
25 Phong Model plot a BRDF as a function of ω o for a fixed ω i 25
26 Phong Model plot a BRDF as a function of ω o for a fixed ω i 26
27 Cook-Torrance Model Mathematic model for specular reflection Assume the surface consists of small facets Derive the reflectance as the overall behavior of facets Features of this model: Named after Robert Cook and Kenneth Torrance Also known as Torrance-Sparrow model Assume surface consists of microfacets Assume each facet is a perfect mirror 27
28 Cook-Torrance Model 28
29 Questions? 29
30 Measuring the BRDF traditional Capture the BRDF by moving a camera + light source Need careful control of illumination, environment 30
31 Acquisition A spherically homogeneous sample of the material can make the acquisition simpler A sphere contains all kinds of normals So a single image contains many BRDF samples lamp controlled turntable sample Digital camera 31
32 Represent Measured Data Measure-then-fit analytic models Fitting can reduce noise but also is limited by the model Non-obvious error metric for fitting often biased to specular which has large values Difficult optimization nonlinear; depends on initial guess Tabulated BRDF 4D table Not editable 32
33 Acquisition 130 materials were scanned; 100 of them shown here MERL BRDF database, freely available online 33
34 Tabulated BRDF nickel hematite gold paint pink fabric 34
35 Questions? 35
36 PAMI 2005 Example-based Photometric Stereo 36 Aaron Hertzmann University of Toronto Steven M. Seitz University of Washington
37 Shiny things 37 Orientation consistency : points of similar orientation have similar intensity
38 38 One to many mapping. Normal at this pixel cannot be determined by referring to the sphere
39 Let s get multiple images. 39
40 40
41 41
42 42
43 43
44 Virtual views 44
45 Velvet 45
46 Virtual Views 46
47 Brushed Fur 47
48 48
49 49
50 Questions? 50
51 51 ( ) ( ) i o i o i i o o ϕ ϕ θ θ ρ ϕ θ ϕ θ ρ =,,,,, ( ) ( ) ( ),,,,,, o i i o o i i o i o i o ϕ ϕ θ θ ρ ϕ ϕ θ θ ρ ϕ ϕ θ θ ρ = = BRDF Symmetries Most of real materials are isotropic
52 Examples ISOTROPIC ANISOTROPIC [Westin et al. 92] 52
CS 5625 Lec 2: Shading Models
CS 5625 Lec 2: Shading Models Kavita Bala Spring 2013 Shading Models Chapter 7 Next few weeks Textures Graphics Pipeline Light Emission To compute images What are the light sources? Light Propagation Fog/Clear?
More informationRadiance. Radiance properties. Radiance properties. Computer Graphics (Fall 2008)
Computer Graphics (Fall 2008) COMS 4160, Lecture 19: Illumination and Shading 2 http://www.cs.columbia.edu/~cs4160 Radiance Power per unit projected area perpendicular to the ray per unit solid angle in
More informationIntroduction. Lighting model Light reflection model Local illumination model Reflectance model BRDF
Shading Introduction Affine transformations help us to place objects into a scene. Before creating images of these objects, we ll look at models for how light interacts with their surfaces. Such a model
More informationw Foley, Section16.1 Reading
Shading w Foley, Section16.1 Reading Introduction So far, we ve talked exclusively about geometry. w What is the shape of an object? w How do I place it in a virtual 3D space? w How do I know which pixels
More informationAnd if that 120MP Camera was cool
Reflectance, Lights and on to photometric stereo CSE 252A Lecture 7 And if that 120MP Camera was cool Large Synoptic Survey Telescope 3.2Gigapixel camera 189 CCD s, each with 16 megapixels Pixels are 10µm
More informationOverview. Radiometry and Photometry. Foundations of Computer Graphics (Spring 2012)
Foundations of Computer Graphics (Spring 2012) CS 184, Lecture 21: Radiometry http://inst.eecs.berkeley.edu/~cs184 Overview Lighting and shading key in computer graphics HW 2 etc. ad-hoc shading models,
More informationBRDF Computer Graphics (Spring 2008)
BRDF Computer Graphics (Spring 2008) COMS 4160, Lecture 20: Illumination and Shading 2 http://www.cs.columbia.edu/~cs4160 Reflected Radiance proportional to Irradiance Constant proportionality: BRDF [CW
More informationReflection models and radiometry Advanced Graphics
Reflection models and radiometry Advanced Graphics Rafał Mantiuk Computer Laboratory, University of Cambridge Applications To render realistic looking materials Applications also in computer vision, optical
More informationLighting affects appearance
Lighting affects appearance 1 Source emits photons Light And then some reach the eye/camera. Photons travel in a straight line When they hit an object they: bounce off in a new direction or are absorbed
More informationShading. Brian Curless CSE 557 Autumn 2017
Shading Brian Curless CSE 557 Autumn 2017 1 Reading Optional: Angel and Shreiner: chapter 5. Marschner and Shirley: chapter 10, chapter 17. Further reading: OpenGL red book, chapter 5. 2 Basic 3D graphics
More informationCMSC427 Shading Intro. Credit: slides from Dr. Zwicker
CMSC427 Shading Intro Credit: slides from Dr. Zwicker 2 Today Shading Introduction Radiometry & BRDFs Local shading models Light sources Shading strategies Shading Compute interaction of light with surfaces
More informationLighting affects appearance
Lighting affects appearance 1 Source emits photons Light And then some reach the eye/camera. Photons travel in a straight line When they hit an object they: bounce off in a new direction or are absorbed
More informationLocal Reflection Models
Local Reflection Models Illumination Thus Far Simple Illumination Models Ambient + Diffuse + Attenuation + Specular Additions Texture, Shadows, Used in global algs! (Ray tracing) Problem: Different materials
More informationShading & Material Appearance
Shading & Material Appearance ACM. All rights reserved. This content is excluded from our Creative Commons license. For more information, see http://ocw.mit.edu/help/faq-fair-use/. MIT EECS 6.837 Matusik
More informationShading I Computer Graphics I, Fall 2008
Shading I 1 Objectives Learn to shade objects ==> images appear threedimensional Introduce types of light-material interactions Build simple reflection model Phong model Can be used with real time graphics
More informationCapturing light. Source: A. Efros
Capturing light Source: A. Efros Review Pinhole projection models What are vanishing points and vanishing lines? What is orthographic projection? How can we approximate orthographic projection? Lenses
More informationCS6670: Computer Vision
CS6670: Computer Vision Noah Snavely Lecture 20: Light, reflectance and photometric stereo Light by Ted Adelson Readings Szeliski, 2.2, 2.3.2 Light by Ted Adelson Readings Szeliski, 2.2, 2.3.2 Properties
More informationAssignment #2. (Due date: 11/6/2012)
Computer Vision I CSE 252a, Fall 2012 David Kriegman Assignment #2 (Due date: 11/6/2012) Name: Student ID: Email: Problem 1 [1 pts] Calculate the number of steradians contained in a spherical wedge with
More informationPhotometric Stereo.
Photometric Stereo Photometric Stereo v.s.. Structure from Shading [1] Photometric stereo is a technique in computer vision for estimating the surface normals of objects by observing that object under
More informationComputer Graphics (CS 4731) Lecture 16: Lighting, Shading and Materials (Part 1)
Computer Graphics (CS 4731) Lecture 16: Lighting, Shading and Materials (Part 1) Prof Emmanuel Agu Computer Science Dept. Worcester Polytechnic Institute (WPI) Why do we need Lighting & shading? Sphere
More informationLecture 4: Reflection Models
Lecture 4: Reflection Models CS 660, Spring 009 Kavita Bala Computer Science Cornell University Outline Light sources Light source characteristics Types of sources Light reflection Physics-based models
More informationShading. Reading. Pinhole camera. Basic 3D graphics. Brian Curless CSE 557 Fall Required: Shirley, Chapter 10
Reading Required: Shirley, Chapter 10 Shading Brian Curless CSE 557 Fall 2014 1 2 Basic 3D graphics With affine matrices, we can now transform virtual 3D objects in their local coordinate systems into
More informationCS6670: Computer Vision
CS6670: Computer Vision Noah Snavely Lecture 21: Light, reflectance and photometric stereo Announcements Final projects Midterm reports due November 24 (next Tuesday) by 11:59pm (upload to CMS) State the
More informationIllumination in Computer Graphics
Illumination in Computer Graphics Ann McNamara Illumination in Computer Graphics Definition of light sources. Analysis of interaction between light and objects in a scene. Rendering images that are faithful
More informationComputer Graphics. Illumination and Shading
Rendering Pipeline modelling of geometry transformation into world coordinates placement of cameras and light sources transformation into camera coordinates backface culling projection clipping w.r.t.
More informationThe Rendering Equation. Computer Graphics CMU /15-662
The Rendering Equation Computer Graphics CMU 15-462/15-662 Review: What is radiance? Radiance at point p in direction N is radiant energy ( #hits ) per unit time, per solid angle, per unit area perpendicular
More informationRadiometry and reflectance
Radiometry and reflectance http://graphics.cs.cmu.edu/courses/15-463 15-463, 15-663, 15-862 Computational Photography Fall 2018, Lecture 16 Course announcements Homework 4 is still ongoing - Any questions?
More informationFundamentals of Rendering - Reflectance Functions
Fundamentals of Rendering - Reflectance Functions Image Synthesis Torsten Möller Mike Phillips Reading Chapter 8 of Physically Based Rendering by Pharr&Humphreys Chapter 16 in Foley, van Dam et al. Chapter
More informationComputer Graphics (CS 543) Lecture 7b: Intro to lighting, Shading and Materials + Phong Lighting Model
Computer Graphics (CS 543) Lecture 7b: Intro to lighting, Shading and Materials + Phong Lighting Model Prof Emmanuel Agu Computer Science Dept. Worcester Polytechnic Institute (WPI) Why do we need Lighting
More informationSimple Lighting/Illumination Models
Simple Lighting/Illumination Models Scene rendered using direct lighting only Photograph Scene rendered using a physically-based global illumination model with manual tuning of colors (Frederic Drago and
More informationLecture 22: Basic Image Formation CAP 5415
Lecture 22: Basic Image Formation CAP 5415 Today We've talked about the geometry of scenes and how that affects the image We haven't talked about light yet Today, we will talk about image formation and
More informationIllumination & Shading
Illumination & Shading Goals Introduce the types of light-material interactions Build a simple reflection model---the Phong model--- that can be used with real time graphics hardware Why we need Illumination
More informationIllumination and Shading - II
Illumination and Shading - II Computer Graphics COMP 770 (236) Spring 2007 Instructor: Brandon Lloyd 2/19/07 1 From last time Light Sources Empirical Illumination Shading Local vs Global Illumination 2/19/07
More informationCSE 167: Introduction to Computer Graphics Lecture #6: Lights. Jürgen P. Schulze, Ph.D. University of California, San Diego Fall Quarter 2016
CSE 167: Introduction to Computer Graphics Lecture #6: Lights Jürgen P. Schulze, Ph.D. University of California, San Diego Fall Quarter 2016 Announcements Thursday in class: midterm #1 Closed book Material
More informationAnnouncement. Lighting and Photometric Stereo. Computer Vision I. Surface Reflectance Models. Lambertian (Diffuse) Surface.
Lighting and Photometric Stereo CSE252A Lecture 7 Announcement Read Chapter 2 of Forsyth & Ponce Might find section 12.1.3 of Forsyth & Ponce useful. HW Problem Emitted radiance in direction f r for incident
More informationTimothy Walsh. Reflection Models
Timothy Walsh Reflection Models Outline Reflection Models Geometric Setting Fresnel Reflectance Specular Refletance & Transmission Microfacet Models Lafortune Model Fresnel Incidence Effects Diffuse Scatter
More informationReading. Shading. An abundance of photons. Introduction. Required: Angel , 6.5, Optional: Angel 6.4 OpenGL red book, chapter 5.
Reading Required: Angel 6.1-6.3, 6.5, 6.7-6.8 Optional: Shading Angel 6.4 OpenGL red book, chapter 5. 1 2 Introduction An abundance of photons So far, we ve talked exclusively about geometry. Properly
More informationTopic 9: Lighting & Reflection models 9/10/2016. Spot the differences. Terminology. Two Components of Illumination. Ambient Light Source
Topic 9: Lighting & Reflection models Lighting & reflection The Phong reflection model diffuse component ambient component specular component Spot the differences Terminology Illumination The transport
More informationCENG 477 Introduction to Computer Graphics. Ray Tracing: Shading
CENG 477 Introduction to Computer Graphics Ray Tracing: Shading Last Week Until now we learned: How to create the primary rays from the given camera and image plane parameters How to intersect these rays
More informationCSE 681 Illumination and Phong Shading
CSE 681 Illumination and Phong Shading Physics tells us What is Light? We don t see objects, we see light reflected off of objects Light is a particle and a wave The frequency of light What is Color? Our
More informationTopic 9: Lighting & Reflection models. Lighting & reflection The Phong reflection model diffuse component ambient component specular component
Topic 9: Lighting & Reflection models Lighting & reflection The Phong reflection model diffuse component ambient component specular component Spot the differences Terminology Illumination The transport
More informationImage Formation: Light and Shading. Introduction to Computer Vision CSE 152 Lecture 3
Image Formation: Light and Shading CSE 152 Lecture 3 Announcements Homework 1 is due Apr 11, 11:59 PM Homework 2 will be assigned on Apr 11 Reading: Chapter 2: Light and Shading Geometric image formation
More informationIllumination. Michael Kazhdan ( /657) HB Ch. 14.1, 14.2 FvDFH 16.1, 16.2
Illumination Michael Kazhdan (601.457/657) HB Ch. 14.1, 14.2 FvDFH 16.1, 16.2 Ray Casting Image RayCast(Camera camera, Scene scene, int width, int height) { Image image = new Image(width, height); for
More informationLecture 15: Shading-I. CITS3003 Graphics & Animation
Lecture 15: Shading-I CITS3003 Graphics & Animation E. Angel and D. Shreiner: Interactive Computer Graphics 6E Addison-Wesley 2012 Objectives Learn that with appropriate shading so objects appear as threedimensional
More informationLigh%ng and Reflectance
Ligh%ng and Reflectance 2 3 4 Ligh%ng Ligh%ng can have a big effect on how an object looks. Modeling the effect of ligh%ng can be used for: Recogni%on par%cularly face recogni%on Shape reconstruc%on Mo%on
More informationIllumination. Illumination CMSC 435/634
Illumination CMSC 435/634 Illumination Interpolation Illumination Illumination Interpolation Illumination Illumination Effect of light on objects Mostly look just at intensity Apply to each color channel
More informationFundamentals of Rendering - Reflectance Functions
Fundamentals of Rendering - Reflectance Functions CMPT 461/761 Image Synthesis Torsten Möller Reading Chapter 8 of Physically Based Rendering by Pharr&Humphreys Chapter 16 in Foley, van Dam et al. Chapter
More informationToday. Global illumination. Shading. Interactive applications. Rendering pipeline. Computergrafik. Shading Introduction Local shading models
Computergrafik Matthias Zwicker Universität Bern Herbst 2009 Today Introduction Local shading models Light sources strategies Compute interaction of light with surfaces Requires simulation of physics Global
More informationCSE 167: Lecture #7: Color and Shading. Jürgen P. Schulze, Ph.D. University of California, San Diego Fall Quarter 2011
CSE 167: Introduction to Computer Graphics Lecture #7: Color and Shading Jürgen P. Schulze, Ph.D. University of California, San Diego Fall Quarter 2011 Announcements Homework project #3 due this Friday,
More informationAnnouncements. Image Formation: Light and Shading. Photometric image formation. Geometric image formation
Announcements Image Formation: Light and Shading Homework 0 is due Oct 5, 11:59 PM Homework 1 will be assigned on Oct 5 Reading: Chapters 2: Light and Shading CSE 252A Lecture 3 Geometric image formation
More informationRadiometry. Reflectance & Lighting. Solid Angle. Radiance. Radiance Power is energy per unit time
Radiometry Reflectance & Lighting Computer Vision I CSE5A Lecture 6 Read Chapter 4 of Ponce & Forsyth Homework 1 Assigned Outline Solid Angle Irradiance Radiance BRDF Lambertian/Phong BRDF By analogy with
More informationCPSC / Illumination and Shading
CPSC 599.64 / 601.64 Rendering Pipeline usually in one step modelling of geometry transformation into world coordinate system placement of cameras and light sources transformation into camera coordinate
More informationExperimental Validation of Analytical BRDF Models
Experimental Validation of Analytical BRDF Models Addy Ngan, Frédo Durand, Wojciech Matusik Massachusetts Institute of Technology Goal Evaluate and analyze the performance of analytical reflectance models
More informationComp 410/510 Computer Graphics. Spring Shading
Comp 410/510 Computer Graphics Spring 2017 Shading Why we need shading Suppose we build a model of a sphere using many polygons and then color it using a fixed color. We get something like But we rather
More informationLighting Models. CS116B Chris Pollett Mar 21, 2004.
Lighting Models CS116B Chris Pollett Mar 21, 2004. Outline Overview Light Sources Surface Lighting Effect Basic Illumination Models Overview An illumination model (lighting model) is used to calculate
More informationOther approaches to obtaining 3D structure
Other approaches to obtaining 3D structure Active stereo with structured light Project structured light patterns onto the object simplifies the correspondence problem Allows us to use only one camera camera
More informationRendering Light Reflection Models
Rendering Light Reflection Models Visual Imaging in the Electronic Age Donald P. Greenberg October 3, 2017 Lecture #13 Program of Computer Graphics, Cornell University General Electric - 167 Cornell in
More informationSung-Eui Yoon ( 윤성의 )
CS380: Computer Graphics Illumination and Shading Sung-Eui Yoon ( 윤성의 ) Course URL: http://sglab.kaist.ac.kr/~sungeui/cg/ Course Objectives (Ch. 10) Know how to consider lights during rendering models
More informationPath Tracing part 2. Steve Rotenberg CSE168: Rendering Algorithms UCSD, Spring 2017
Path Tracing part 2 Steve Rotenberg CSE168: Rendering Algorithms UCSD, Spring 2017 Monte Carlo Integration Monte Carlo Integration The rendering (& radiance) equation is an infinitely recursive integral
More informationInteractive Real-Time Raycasting
Interactive Real-Time Raycasting CS184 AS4 Due 2009-02-26 11:00pm We start our exploration of Rendering - the process of converting a high-level object-based description into a graphical image for display.
More informationBRDFs. Steve Rotenberg CSE168: Rendering Algorithms UCSD, Spring 2017
BRDFs Steve Rotenberg CSE168: Rendering Algorithms UCSD, Spring 2017 The Rendering Equation Radiance Radiance is a measure of the quantity of light radiation reflected (and/or emitted) from a surface within
More informationEpipolar geometry contd.
Epipolar geometry contd. Estimating F 8-point algorithm The fundamental matrix F is defined by x' T Fx = 0 for any pair of matches x and x in two images. Let x=(u,v,1) T and x =(u,v,1) T, each match gives
More informationGlobal Illumination The Game of Light Transport. Jian Huang
Global Illumination The Game of Light Transport Jian Huang Looking Back Ray-tracing and radiosity both computes global illumination Is there a more general methodology? It s a game of light transport.
More informationA question from Piazza
Radiometry, Reflectance, Lights CSE 252A Lecture 6 A question from Piazza 1 Announcements HW1 posted HWO graded, will be returned today If anyone has any registration issues, talk to me. Appearance: lighting,
More informationSurface Reflection Models
Surface Reflection Models Frank Losasso (flosasso@nvidia.com) Introduction One of the fundamental topics in lighting is how the light interacts with the environment. The academic community has researched
More informationLighting. Figure 10.1
We have learned to build three-dimensional graphical models and to display them. However, if you render one of our models, you might be disappointed to see images that look flat and thus fail to show the
More informationComputer Graphics. Illumination and Shading
() Illumination and Shading Dr. Ayman Eldeib Lighting So given a 3-D triangle and a 3-D viewpoint, we can set the right pixels But what color should those pixels be? If we re attempting to create a realistic
More informationdq dt I = Irradiance or Light Intensity is Flux Φ per area A (W/m 2 ) Φ =
Radiometry (From Intro to Optics, Pedrotti -4) Radiometry is measurement of Emag radiation (light) Consider a small spherical source Total energy radiating from the body over some time is Q total Radiant
More informationdq dt I = Irradiance or Light Intensity is Flux Φ per area A (W/m 2 ) Φ =
Radiometry (From Intro to Optics, Pedrotti -4) Radiometry is measurement of Emag radiation (light) Consider a small spherical source Total energy radiating from the body over some time is Q total Radiant
More informationShading. Brian Curless CSE 457 Spring 2017
Shading Brian Curless CSE 457 Spring 2017 1 Reading Optional: Angel and Shreiner: chapter 5. Marschner and Shirley: chapter 10, chapter 17. Further reading: OpenGL red book, chapter 5. 2 Basic 3D graphics
More informationRadiometry. Radiometry. Measuring Angle. Solid Angle. Radiance
Radiometry Radiometry Computer Vision I CSE5A ecture 5-Part II Read Chapter 4 of Ponce & Forsyth Solid Angle Irradiance Radiance BRDF ambertian/phong BRDF Measuring Angle Solid Angle By analogy with angle
More informationUnderstanding Variability
Understanding Variability Why so different? Light and Optics Pinhole camera model Perspective projection Thin lens model Fundamental equation Distortion: spherical & chromatic aberration, radial distortion
More informationToday. Global illumination. Shading. Interactive applications. Rendering pipeline. Computergrafik. Shading Introduction Local shading models
Computergrafik Thomas Buchberger, Matthias Zwicker Universität Bern Herbst 2008 Today Introduction Local shading models Light sources strategies Compute interaction of light with surfaces Requires simulation
More informationLighting and Shading. Slides: Tamar Shinar, Victor Zordon
Lighting and Shading Slides: Tamar Shinar, Victor Zordon Why we need shading Suppose we build a model of a sphere using many polygons and color each the same color. We get something like But we want 2
More informationShading / Light. Thanks to Srinivas Narasimhan, Langer-Zucker, Henrik Wann Jensen, Ravi Ramamoorthi, Hanrahan, Preetham
Shading / Light Thanks to Srinivas Narasimhan, Langer-Zucker, Henrik Wann Jensen, Ravi Ramamoorthi, Hanrahan, Preetham Phong Illumination Model See Shirley, Ch 10 and http://en.wikipedia.org/wiki/phong_shading
More informationAnnouncements. Light. Properties of light. Light. Project status reports on Wednesday. Readings. Today. Readings Szeliski, 2.2, 2.3.
Announcements Project status reports on Wednesday prepare 5 minute ppt presentation should contain: problem statement (1 slide) description of approach (1 slide) some images (1 slide) current status +
More informationIllumination Models and Shading
1 Illumination Models and Shading Motivation: In order to produce realistic images, we must simulate the appearance of surfaces under various lighting conditions. Illumination Models: Given the illumination
More information2/1/10. Outline. The Radiance Equation. Light: Flux Equilibrium. Light: Radiant Power. Light: Equation. Radiance. Jan Kautz
Outline Jan Kautz Basic terms in radiometry Radiance Reflectance The operator form of the radiance equation Meaning of the operator form Approximations to the radiance equation 2005 Mel Slater, 2006 Céline
More informationIllumination & Shading I
CS 543: Computer Graphics Illumination & Shading I Robert W. Lindeman Associate Professor Interactive Media & Game Development Department of Computer Science Worcester Polytechnic Institute gogo@wpi.edu
More informationAnnouncements. Radiometry and Sources, Shadows, and Shading
Announcements Radiometry and Sources, Shadows, and Shading CSE 252A Lecture 6 Instructor office hours This week only: Thursday, 3:45 PM-4:45 PM Tuesdays 6:30 PM-7:30 PM Library (for now) Homework 1 is
More informationIllumination and Shading
Illumination and Shading Computer Graphics COMP 770 (236) Spring 2007 Instructor: Brandon Lloyd 2/14/07 1 From last time Texture mapping overview notation wrapping Perspective-correct interpolation Texture
More informationReading. Shading. Introduction. An abundance of photons. Required: Angel , Optional: OpenGL red book, chapter 5.
Reading Required: Angel 6.1-6.5, 6.7-6.8 Optional: Shading OpenGL red book, chapter 5. 1 2 Introduction So far, we ve talked exclusively about geometry. What is the shape of an obect? How do I place it
More informationComplex Shading Algorithms
Complex Shading Algorithms CPSC 414 Overview So far Rendering Pipeline including recent developments Today Shading algorithms based on the Rendering Pipeline Arbitrary reflection models (BRDFs) Bump mapping
More informationINFOGR Computer Graphics. J. Bikker - April-July Lecture 10: Shading Models. Welcome!
INFOGR Computer Graphics J. Bikker - April-July 2016 - Lecture 10: Shading Models Welcome! Today s Agenda: Introduction Light Transport Materials Sensors Shading INFOGR Lecture 10 Shading Models 3 Introduction
More informationLighting and Reflectance COS 426
ighting and Reflectance COS 426 Ray Casting R2mage *RayCast(R3Scene *scene, int width, int height) { R2mage *image = new R2mage(width, height); for (int i = 0; i < width; i++) { for (int j = 0; j < height;
More informationPaths, diffuse interreflections, caching and radiometry. D.A. Forsyth
Paths, diffuse interreflections, caching and radiometry D.A. Forsyth How we got here We want to render diffuse interreflections strategy: compute approximation B-hat, then gather B = E +(ρk)e +(ρk)( ˆB
More informationGlobal Illumination. CSCI 420 Computer Graphics Lecture 18. BRDFs Raytracing and Radiosity Subsurface Scattering Photon Mapping [Ch
CSCI 420 Computer Graphics Lecture 18 Global Illumination Jernej Barbic University of Southern California BRDFs Raytracing and Radiosity Subsurface Scattering Photon Mapping [Ch. 13.4-13.5] 1 Global Illumination
More informationCPSC 314 LIGHTING AND SHADING
CPSC 314 LIGHTING AND SHADING UGRAD.CS.UBC.CA/~CS314 slide credits: Mikhail Bessmeltsev et al 1 THE RENDERING PIPELINE Vertices and attributes Vertex Shader Modelview transform Per-vertex attributes Vertex
More informationIllumination & Shading: Part 1
Illumination & Shading: Part 1 Light Sources Empirical Illumination Shading Local vs Global Illumination Lecture 10 Comp 236 Spring 2005 Computer Graphics Jargon: Illumination Models Illumination - the
More informationShading. Why we need shading. Scattering. Shading. Objectives
Shading Why we need shading Objectives Learn to shade objects so their images appear three-dimensional Suppose we build a model of a sphere using many polygons and color it with glcolor. We get something
More informationGlobal Illumination. CMPT 361 Introduction to Computer Graphics Torsten Möller. Machiraju/Zhang/Möller
Global Illumination CMPT 361 Introduction to Computer Graphics Torsten Möller Reading Foley, van Dam (better): Chapter 16.7-13 Angel: Chapter 5.11, 11.1-11.5 2 Limitation of local illumination A concrete
More informationGlobal Illumination. Global Illumination. Direct Illumination vs. Global Illumination. Indirect Illumination. Soft Shadows.
CSCI 420 Computer Graphics Lecture 18 Global Illumination Jernej Barbic University of Southern California BRDFs Raytracing and Radiosity Subsurface Scattering Photon Mapping [Angel Ch. 11] 1 Global Illumination
More informationLecture 7 - Path Tracing
INFOMAGR Advanced Graphics Jacco Bikker - November 2016 - February 2017 Lecture 7 - I x, x = g(x, x ) ε x, x + S ρ x, x, x I x, x dx Welcome! Today s Agenda: Introduction Advanced Graphics 3 Introduction
More informationCS130 : Computer Graphics Lecture 8: Lighting and Shading. Tamar Shinar Computer Science & Engineering UC Riverside
CS130 : Computer Graphics Lecture 8: Lighting and Shading Tamar Shinar Computer Science & Engineering UC Riverside Why we need shading Suppose we build a model of a sphere using many polygons and color
More informationIllumination and Shading
Illumination and Shading Illumination (Lighting)! Model the interaction of light with surface points to determine their final color and brightness! The illumination can be computed either at vertices or
More informationShading and Illumination
Shading and Illumination OpenGL Shading Without Shading With Shading Physics Bidirectional Reflectance Distribution Function (BRDF) f r (ω i,ω ) = dl(ω ) L(ω i )cosθ i dω i = dl(ω ) L(ω i )( ω i n)dω
More informationRay Tracing: shading
Ray Tracing: shading CS 4620 Lecture 6 2018 Steve Marschner 1 Image so far With eye ray generation and scene intersection for 0
More informationRadiance. Pixels measure radiance. This pixel Measures radiance along this ray
Photometric stereo Radiance Pixels measure radiance This pixel Measures radiance along this ray Where do the rays come from? Rays from the light source reflect off a surface and reach camera Reflection:
More informationRaytracing CS148 AS3. Due :59pm PDT
Raytracing CS148 AS3 Due 2010-07-25 11:59pm PDT We start our exploration of Rendering - the process of converting a high-level object-based description of scene into an image. We will do this by building
More informationRadiometry Measuring Light
1 Radiometry Measuring Light CS 554 Computer Vision Pinar Duygulu Bilkent University 2 How do we see? [Plato] from our eyes flows a light similar to the light of the sun [Chalcidius, middle ages] Therefore,
More information