3D Photometrycvlab.khu.ac.kr/DHLecture4.pdf · 2019. 3. 19. · Image Photometry Slide source: Bob...
Transcript of 3D Photometrycvlab.khu.ac.kr/DHLecture4.pdf · 2019. 3. 19. · Image Photometry Slide source: Bob...
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3D Photometry
2019 Spring
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Image Photometry
Slide source: Bob Collins
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Image Photometry
Slide source: Bob Collins
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Image Photometry
Slide source: Bob Collins
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Image Photometry
Slide source: Bob Collins
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Image Photometry
Slide source: Bob Collins
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Image Photometry
Slide source: Bob Collins
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Image Photometry
Slide source: Bob Collins
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Image Photometry
Slide source: Bob Collins
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Image Photometry
Slide source: Bob Collins
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Reflection Model
f f
Perfect
Diffuse
Perfect
Mirror
irradiance
radiancef
Bidirectional Reflectance Distribution Function
: is the ratio of the radiance in the outgoing direction to the incident irradiance.
: defines how light is reflected at an opaque surface.
albedo
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Simple BRDF Acquisition using Single Camera and Single Separate Light Source
Camera
Light
Move Camera? or Object?
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Phong reflection model
n
soiphong crrf )(cos),(
),( or rrangle
Diffuse
(Lambertian)
Specularity ≒ roughness
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Torrance-Sparrow BRDF
A type of microfacets BRDF
ri
FGDf
coscos
Gaussian distribution of a microfacet
Self-occlusion
Fresnel
1. Complex and not practical
2. For graphics rendering, not for detection
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Ward BRDF Measured Data based BRDF
)exp(
Af
Single Gaussian distribution
(including occlusion, Fresnel)
Lafortune BRDF
Combines multiple lobs
Image-based BRDF - Marschner BRDF : HDR image - Data-Driven reflectance model : set of physically meaningful BRDF basis : interpolate them