gazihan alankus gazihan@cse.wustl

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Vision-Realistic Rendering: Simulation of the Scanned Foveal Image from Wavefront Data of

Human Subjects, Brian A. Barsky, 2004

Gazihan Alankusgazihan@cse.wustl.edu

212/03/2004

Introduction

● A new concept: vision-realistic rendering– Rendering scenes as someone really sees them– Simulating the optical properties of the eye to get the

retinal image● Applications

– Creating more realistic renderings– Educating eye doctors and patients

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Ideal Way

● Trace rays from every photoreceptor in retina– Not feasible with current technology

● Approximation using wavefront aberromery– A technology used for laser surgeries such as LASIK– Measures only one point in retina with a laser beam

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Wavefront Aberrometry

● 1mm laser beam is sent to the fovea using the half-silvered mirror

● Fovea acts as a point light source and sends light out of the eye

● The light is focused on the sensor using a lenslet array

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Wavefront Aberrometry

Actual Image

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Algorithm

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Object Space Point Spread Function

● The vectors computed using the displacements of spots are converted to a surface using Zernkie polynomials

● A continuous blurring function in object space is necessary– A discrete approximated version is used for a number

of depth levels (Depth point spread functions)– Each surface normal is traced and counters in grids of

given depth levels are incremented, and normalized at the end

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Rendering

● In order to see the whole image, people scan the image by moving their eyes

● All the image is rendered using the simulation for the fovea– Looks realistic since people will move their eyes to

see the whole image

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Rendering

● For each chosen depth, an image is rendered● Each depth image is convolved with its

corresponding grid (DPSF)● A composite image is created using alpha

blending from far to near

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Results

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Results

Patient with keratoconus

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Results

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Results

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Results

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Conclusion

● The image on the fovea is simulated to have a much better perceptually realistic image

● How patients with certain eye conditions see is made available for education and better treatment

● Whole image is rendered using the same distortion– If we have the technology to get information about

more than one spot on retina, eye tracking can be used to show different renderings at different eye directions