RAYS (Render As You See) Vision-Realistic Rendering Using Hartmann-Shack Wavefront Aberrations Brian A. Barsky Daniel D. Garcia Stanley A. Klein Woojin M. Yu Billy P. Chen Sarang S. Dalal 11/28/2018
Motivation CWhatUC ray tracing approach similar to Kolb, but with corneal topography 3 Major Limitations computation time small light sources artifacts from the model 11/28/2018
The Algorithm (our goal) color image with depth values fixation point and wavefront data generate an image with depth of field and visual artifacts consistent with the wavefront 11/28/2018
Hartmann-Shack Device 11/28/2018
Hartmann-Shack Device 11/28/2018
Hartmann-Shack Device 11/28/2018
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Resampling Hartmann-Shack wavefront data encodes gradient/slope of wavefront however, sampling is very sparse! Solution: fit a Zernike polynomial to these samples resample at higher rate 11/28/2018
Point Spread Function 2D Retinal energy histogram PSF as a blur filter and subsequent convolution with image 11/28/2018
Object-Space Point Spread Function (OSPSF) analog to the traditional PSF used for wavefronts image-space PSF vs. object-space OSPSF array of OSPSF’s at each depth plane OSPSF as a generalization of PSF lens to pick fixation point at each depth plane, a tuned diverging lens converts a wavefront converging at that depth to a plane wave 11/28/2018
Depth Planes A person with 20/20 vision can perceive a subtended angle of one minute = pD Assuming a typical pupil diameter of 2.4mm D = 0.12 diopters We use D = 0.25 diopters, but the maximum error is half the chosen precision Consider a point 1.6 meters away from the lens optometrists typically use 0.25 diopter increments for corrective lenses 11/28/2018
Depth Planes The range of sharp human vision is 10cm to infinity At 0.25 diopter increments, we use 41 depth planes spaced from 0D (infinitely far) to 40D (10 cm) Depth planes are placed densely closer to the observer, and more sparsely as it approaches infinity 11/28/2018
Rendering Image PRMan RGBZ values 11/28/2018
Stratification image pixels are separated according to depth values into “depth strata” continuous depth values are quantized into discrete values 11/28/2018
Convolution and Accumulation OSPSF’s are convolved with each appropriate depth strata Blurred images corresponding depth planes are accumulated together 11/28/2018
Example Images Cubes Road to Pt. RAYS 11/28/2018
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Conclusion Vision-realistic Rendering Render As You See (RAYS) Example images 11/28/2018