Rendering Synthetic Objects into Legacy Photographs
Kevin Karsch
Varsha Hedau
David Forsyth
Derek Hoiem
University of Illinois at Urbana-Champaign
cfw_karsch1,vhedau2,daf,dhoiem@uiuc.edu
Figure 1: With only a small amount of user interaction, our system a
CGR Recap
2015
Qualities of Light
Color temperature determines the color of the light.
Brightness is based on the exposure settings of the
camera.
Softness is a function of several settings on a light:
Penumbra: softness of the edge of a spotlights con
Claus B. Madsen, AD:MT/AAU
CGR
INTRODUCTION TO
AUGMENTATION
Alternative
augmentation
Overview
The three problems of augmentation
1. Tracking (camera calibration)
2. Occlusion (scene geometry)
3. Illumination (consistency)
An augmentation example
1. Matc
CGR Lesson: 5-6
Mathematics behind
Raytracing
1
2
3
But first things,
first.
4
Content
Lines, incl. rays and segments
Planes, incl. polygons and triangles
Their distances and intersections
In chapters: 5.1, 5.2, 6.2 from Lengyels book
5
Needed from pre
CGR Lesson: 10
Rendering in Layers
3D graphics usually not rendered all as
a single image
Visual effects: composite 3D elements lit and
rendered into scenes in order to seamlessly
integrate them into real environments
Productions entirely animated also
CGR Lesson: 7
Mathematics behind
Raytracing Shortest
distances
1
Distance between point and line
Q
Given:
Line L(t ) P tv
0
Point Q not belonging
to line p
L
v
Q1 = P0 +tv
P0
Find: dist(Q, L)
2
In how many dimensions is this
problem stated?
Q
v and P0
CGR Lesson 09:
Lighting
Math Models
Interaction between light and surface
To model it using todays physics would be too
computationally time-consuming
Models that approximate the expected
appearance of a surface
simple models widely used because are
co
CGR Lesson 8:
Reflection and
Refraction Vector
Calculation
Calculation of the
reflection vector
Projection of L on N
Component of L perpendicular to the
normal
R at twice the distance from L as its
projection onto the normal vector N
R = L 2[L-(NL)N] = 2(
1
Shaders
Definitions of how 3D objects respond to light
that describe their surface appearance or how
they will be rendered
2
Diffuse, Glossy, Specular Reflection
3
Diffuse, Glossy, and Specular Reflection in
Shaders
Most surfaces exhibit a combination
CGR Lesson 02:
Shadows
1
The visual functions of shadows
Defining spatial relationship
2
The visual functions of shadows
Revealing alternate angles
3
The visual functions of shadows
Enhancing composition adding contrast
4
The visual functions of shadows
I
CGR Lesson 01:
Lighting Basics
1
The Lighting Problem
Given a point P on a surface S, and a light source L,
what is the intensity seen by viewer V?
2
Observation of nature gives some suggestions
What are possible factors?
3
4
5
Caravaggio
Still Life with
CGR Lesson 03:
Cameras
1
Motivation
Understand how real photography works in order to match
or simulate the effects of a real camera in computer graphics
Shoot bracketed sets of shots for creating High Dynamic
Range Images (HDRIs) to capture the lighting