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Millions of people worldwide need glasses or contact lenses to see or read properly. We introduce a computational display technology that predistorts the presented content for an observer, so that the target image is perceived without the need for eyewear. We demonstrate a low-cost prototype that can correct myopia, hyperopia, astigmatism, and even higher-order aberrations that are difficult to correct with glasses.
Citation preview
Eyeglasses-free Display:
Towards Correcting Visual Aberrations with
Computational Light Field Displays
Fu-Chung Huang1,+ Gordon Wetzstein2,# Brian A. Barsky1 Ramesh Raskar2
University of California, Berkeley
MIT Media Lab
now at Microsoft
now at Stanford University
1
2
+
#
shown at 350mm
normal display
distance to display
focal
range
perceived image
normal display
distance to display
focal
range
pinhole array mask parallax barrier based light field display
25%
U.S. population of hyperopia (far-sightedness)
[Krachmer et al. 2005]
43%
age 40
U.S. population of presbyopia (need reading eyeglasses)
[Katz et al. 1997]
68%
age 80+
[Katz et al. 1997]
U.S. population of presbyopia (need reading eyeglasses)
43%
age 40
U.S. population of myopia (near-sightedness)
41.6%
[Vitale et al. 2009]
Myopia in some Asian countries
60% ~ 90%
[Rajan et al. 1995] [Wong et al. 2000]
[Takashima et al. 2001] [Lin et al. 2004]
Irregular Blurring in VisionPSF PSF PSF
caused by higher-order aberrations
Nirmud lens (?)
9th century
reading stone
1284
Salvino D’Armato
1508
concept
1760
Benjamin Franklin
1880
August Mueller
1983
PRK and LASIK
now
934 B.C.
Computational light field display
(eye-tracking)
(input data)
Prior Work
Projector Precompensation- Brown et al. [2006]
- Zhang and Nayer [2006]
- Oyamada et al. [2007]
- Grosse et al. [2010]
Computational Displays
- Lanman et al. [2010]
- Wetzstein et al. [2012]
- Maimone et al. [2013]
- Hirsch et al. [2014]
- Akeley et al. [2004]
Computational Vision Correction- Alonso and Barreto [2003]
- Yellot and Yellot [2007]
- Huang et al. [2012]
- Pamplona et al. [2012]
- Ji et al. [2014]
- Huang and Barsky [2011]
How to Build a Vision Correcting Display
Spatial domain Frequency domain
=
⊗ ∗
=
𝑖𝑚𝑔 ∗ 𝑝𝑠𝑓 = 𝑏𝑙𝑢𝑟𝑖𝑚𝑔 ⊗ 𝑝𝑠𝑓 = 𝑏𝑙𝑢𝑟
Spatial domain Frequency domain
∗
=
−1 𝑖𝑚𝑔 ∗ 𝑝𝑠𝑓 = 𝑝𝑟𝑒
=
𝑖𝑚𝑔 ⊗ 𝑝𝑠𝑓 = 𝑝𝑟𝑒
⊗
−1
Spatial domain Frequency domain
prefiltered
perceived
=
𝑖𝑚𝑔 ⊗ 𝑝𝑠𝑓 = 𝑝𝑟𝑒
⊗
−1
Spatial domain
plane of focus time-multiplexed
PSFPSF
[Huang et al. 2012]
without correction multilayer displayconventional display
(simple inversion)
7x7 views into the eye
[Pamplona et al. 2012]
without correction
corrected vision
pupil aperture
Inversely Prefilter the Light Field
target image prefiltered light field
Flatland Light Field Projection
retina
𝐼(𝑥) = −∞
+∞
𝑙 𝑥, 𝑢 𝐴 𝑢 𝑑𝑢Retinal image:
𝒙𝒖
𝒙
𝒖
display
focus plane
(1D image + 1D direction)
Light Field Projection
𝐼(𝑥) = −∞
+∞
𝑙 𝑥, 𝑢 𝐴 𝑢 𝑑𝑢Retinal image:
𝒙
𝒖
retinadisplay
focus plane
𝒙𝒖
“Defocus” Light Field Projection
focus plane
𝒙
𝒖
retinadisplay
𝒙𝒖
“Defocus” Light Field Projection
focus plane
𝒙
𝒖
retinadisplay
𝒙𝒖
convolution
“Defocus” Light Field Projection
focus plane
𝒙
𝒖
retinadisplay
𝒙𝒖
convolution
𝝎𝒙
𝝎𝒖
frequency domain
analysis (in the paper)
Using a Light Field Display
𝒙
𝒖
𝒍𝒅
= −𝑟/2
𝑟/2
𝑙𝑑 Ψ𝑥𝑢
𝑑𝑢
𝐼(𝑥) = −∞
+∞
𝑙 𝑥, 𝑢 𝐴 𝑢 𝑑𝑢Retinal image:
more degreesof freedom
focus plane
retina
𝒙𝒖
Using a Light Field Display𝒍𝒅
= −𝑟/2
𝑟/2
𝑙𝑑 Ψ𝑥𝑢
𝑑𝑢
𝐼(𝑥) = −∞
+∞
𝑙 𝑥, 𝑢 𝐴 𝑢 𝑑𝑢Retinal image:
focus plane
retina
𝒙𝒖
?
Using a Light Field Display𝒍𝒅 𝒙𝒖
?𝐏 ∙ 𝐋𝒅 𝐈=
Using a Light Field Display𝒍𝒅 𝒙𝒖
?𝐋𝒅 𝐈= 𝐏−𝟏𝐏 ∙
Using a Light Field Display
𝒙
𝒖
𝒍𝒅
more degreesof freedom
focus plane
retina
𝒙𝒖
𝐋𝒅 𝐈= 𝐏−𝟏
Using a Light Field Display
𝒙
𝒖
𝒍𝒅
more degreesof freedom
focus plane
retina
𝒙𝒖
𝐋𝒅 𝐈= 𝐏−𝟏
become well-posed?
Using a Light Field Display
𝒙
𝒖
𝒍𝒅
more degreesof freedom
focus plane
retina
𝒙𝒖
𝐋𝒅 𝐈= 𝐏−𝟏
become well-posed?
Using a Light Field Display
𝒙
𝒖
𝒍𝒅
more degreesof freedom
focus plane
retina
𝒙𝒖
𝐋𝒅 𝐈= 𝐏−𝟏
become well-posed?
Experiments and Results
250 m
m
focus 3
80 m
m
f = 50 mma = 6 mm
without correction Pamplona et al. 2012multilayer prefilteringtarget image light field prefiltering
HDR-VDP2
Low error detection
Higher Order Aberrations
wit
ho
ut
co
rre
cti
on
co
nve
nti
on
al
dis
pla
y
lig
ht
fie
ld
dis
pla
y
* =
:
::
:
Display light fieldProjection matrices
Axial or lateralmovement
conventionaldisplay
multilayerdisplay
[Pamplona et al.2012][Huang et al.2012] Proposed method
Method Inverse prefiltering Direct ray tracing Prefiltered light field
Spatial Resolution Very High Very Low High
Image Contrast Very Low Full (100%) High
Building Cost High Very High Very Low
light fielddisplay
light fielddisplay
Shortcomings
• Contrast and brightness loss – Content-dependent
• Resolution loss– 3-to-1(DroidDNA), 5-to-1(iPhone)
– about 150 PPI
• Computation– GPU, Mobile
• Calibration– Eye-tracking
– Off-Axis Opt.
Future Work
• Higher Resolution & Large Display– e.g. tensor displays
• Multi-way correction
• Other applications– AR/VR, 3D, Cryptography
• Theoretical analysis– Higher order aberrations
Eyeglasses-free Display
http://web.media.mit.edu/~gordonw/VisionCorrectingDisplay/
http://graphics.berkeley.edu/papers/Huang-EFD-2014-08/
Fu-Chung Huang Gordon Wetzstein
Brian A. Barsky Ramesh Raskar
http://displayblocks.org/
Frequency Domain Analysis
𝝎𝒙
𝝎𝒖
(a) conventional display
(in-focus)
sp
atia
l d
om
ain
fre
qu
en
cy d
om
ain
no angular variations
only spatial energy
𝒙
𝒖
𝝎𝒙
𝝎𝒖
𝒙
𝒖
(a) conventional display
(in-focus)
sp
atia
l d
om
ain
fre
qu
en
cy d
om
ain
pupil function
is a rect(), in umultiplication
( just spreading )pupil response
is a sinc(), in 𝜔𝑢convolution
𝝎𝒙
𝝎𝒖
𝒙
𝒖
(a) conventional display
(in-focus)
sp
atia
l d
om
ain
fre
qu
en
cy d
om
ain
retinal projection
integration in u
slicing at 𝜔𝑢 = 0
𝐼 𝑥
𝐼 𝜔𝑥
Fourier Slice Theorem
𝝎𝒙
𝝎𝒖
𝝎𝒙
𝝎𝒖
𝒙
𝒖
𝒙
𝒖
(a) conventional display
(in-focus)
(b) conventional display
(out-of-focus)
sp
atia
l d
om
ain
fre
qu
en
cy d
om
ain
retinal projection
𝝎𝒙
𝝎𝒖
𝝎𝒙
𝝎𝒖
𝝎𝒙
𝝎𝒖
𝒙
𝒖
𝒙
𝒖
𝒙
𝒖
(a) conventional display
(in-focus)
(b) conventional display
(out-of-focus)
(c) multilayer display
(out-of-focus)
sp
atia
l d
om
ain
fre
qu
en
cy d
om
ain
retinal projection
𝝎𝒙
𝝎𝒖
𝝎𝒙
𝝎𝒖
𝝎𝒙
𝝎𝒖
𝒙
𝒖
𝒙
𝒖
𝒙
𝒖
(a) conventional display
(in-focus)
(b) conventional display
(out-of-focus)
(c) multilayer display
(out-of-focus)
sp
atia
l d
om
ain
fre
qu
en
cy d
om
ain
retinal projection
𝝎𝒖
(d) light field display
(out-of-focus)
𝒙
𝒖
𝝎𝒙
(d) light field display
(out-of-focus)
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