(PPT)光场相机

Pixel P1
Pixel P2
X
Sensor plane: (X,Y) Pixel P1 Pixel P2
Kayvon Fatahalian, Graphics and Imaging Architectures (CMU 15-869, Fall 2011)
Decrease aperture size
Captured light eld
16 MP sensor 296 x 296 micolens array 12 x 12 pixels per microlens
Image: Ng et al. 2006
Kayvon Fatahalian, Graphics and Imaging Architectures (CMU 15-869, Fall 2011)
World plane of focus
Ray space plot
U
Pixel 1
Lens aperture: (U,V)
X
Microlens array Sensor plane: (X,Y)
Pixel 1 Kayvon Fatahalian, Graphics and Imaging Architectures (CMU 15-869, Fall 2011)
Wilburn et al. 2005
Host PC with disk array
Kayvon Fatahalian, Graphics and Imaging Architectures (CMU 15-869, Fall 2011)
Captured light eld
Kayvon Fatahalian, Graphics and Imaging Architectures (CMU 15-869, Fall 2011)
Refocused synthetic aperture image
Kayvon Fatahalian, Graphics and Imaging Architectures (CMU 15-869, Fall 2011)
Plenoptic camera
Adelson and Wang, 1992 Measure plenoptic function for single lens stereo application
De ne LF(u,v) to be sub-aperture image from lens region (u,v)
(Virtual )
Sum of shifted, scaled sub-aperture images Scale image by (can ignore, invariant of lens position) Shift image by ( u(1-1/ ), v(1-1/ ) )
Kayvon Fatahalian, Graphics and Imaging Architectures (CMU 15-869, Fall 2011)
Recall: light- eld
Light eld is a 4D function (represents light in free space: no occlusion)
Potential advantages of light- eld cameras
(For traditional photography)
▪ Remove (or signi cantly simplify) auto-focus
-
Diminished shutter lag Shoot with aperture wide open (traditional camera has shallow depth of eld = high possibility of misfocus) - Can digitally refocus after the shot - Can digitally extend depth of eld Correct for aberrations digitally
Kayvon Fatahalian, Graphics and Imaging Architectures (CMU 15-869, Fall 2011)
Light eld inside a camera
Ray space plot
Scene focal plane
U
Lens aperture: (U,V)
Lecture 18: Light-Field Cameras
(Plenoptic Cameras)
Kayvon Fatahalian CMU 15-869: Graphics and Imaging Architectures (Fall 2011)
Continuing theme: computational photography
Digital refocusing
Lens aperture: (U,V)
Virtual sensor plane: (X’,Y’)
Microlens array Sensor plane: (X,Y)
Kayvon Fatahalian, Graphics and Imaging Architectures (CMU 15-869, Fall 2011)
Synthetic aperture
Simulate image formation by virtual camera with large aperture Shift and add images
Wilburn et al. 2005
Kayvon Fatahalian, Graphics and Imaging Architectures (CMU 15-869, Fall 2011)
Microlens array Sensor plane: (X,Y)
Pixel 1 Pixel 2 Kayvon Fatahalian, Graphics and Imaging Architectures (CMU 15-869, Fall 2011)
Each sensor pixel records a beam of light
Ray space plot
Scene focal plane
U
Lens aperture: (U,V)
Pixel P1
Pixel P2
X
Sensor plane: (X,Y) Pixel P1 Pixel P2
Kayvon Fatahalian, Graphics and Imaging Architectures (CMU 15-869, Fall 2011)
Stanford Camera Array
640 x 480 tightly synchronized, repositionable cameras Custom processing board per camera Tethered to PCs for additional processing/storage
Sub-aperture image
World plane of focus
Lens aperture: (U,V)
Microlens array Sensor plane: (X,Y)
Kayvon Fatahalian, Graphics and Imaging Architectures (CMU 15-869, Fall 2011)
Kayvon Fatahalian, Graphics and Imaging Architectures (CMU 15-869, Fall 2011)
Handheld light eld camera
World plane of focus
Lens aperture: (U,Vdit: Levoy and Hanrahan 96]
Two-plane parameterization: Light ray described by connecting point on (u,v) plane with point on (s,t) plane More general: plenoptic function (Adelson and Bergen 1991)
De ne LF’ using LF
(Virtual )
Image: Ng et al. 2006
Kayvon Fatahalian, Graphics and Imaging Architectures (CMU 15-869, Fall 2011)
Refocused photograph
Integrate all light arriving at point (x’,y’) on F’ plane
Image: Ng et al. 2006
Kayvon Fatahalian, Graphics and Imaging Architectures (CMU 15-869, Fall 2011)
Video
Kayvon Fatahalian, Graphics and Imaging Architectures (CMU 15-869, Fall 2011)
Computing a photograph
World plane of focus
Ray space plot
U
Pixel 1
Lens aperture: (U,V)
Pixel 6
X
Microlens array Sensor plane: (X,Y)
Pixel 1 Pixel 6 Kayvon Fatahalian, Graphics and Imaging Architectures (CMU 15-869, Fall 2011)