Publications

Submitted
Peli E, Jung J-H.; Submitted. Active confocal imaging systems and methods for visual prostheses. United States of America patent US US Provisional Patent Application 2014.
2016
Peli E, Bowers A, Keeney K, Jung J-H. High Power Prismatic Devices for Oblique Peripheral Prisms. Optometry and Vision Science. 2016;93 (5).
2015
Jung J-H, Peli E. Multiplexing prism prescription glasses for field expansion of monocular vision. American Academy of Optometry 2015. 2015.
Jung J-H, Aloni D, Yitzhaky Y, Peli E. Active Confocal Imaging for Visual Prostheses. Vision Research [Internet]. 2015;111 (June) :182-196. Publisher's VersionAbstract

There are encouraging advances in prosthetic vision for the blind, including retinal and cortical implants, and other “sensory substitution devices” that use tactile or electrical stimulation. However, they all have low resolution, limited visual field, and can display only few gray levels (limited dynamic range), severely restricting their utility. To overcome these limitations, image processing or the imaging system could emphasize objects of interest and suppress the background clutter. We propose an active confocal imaging system based on light-field technology that will enable a blind user of any visual prosthesis to efficiently scan, focus on, and “see” only an object of interest while suppressing interference from background clutter. The system captures three-dimensional scene information using a light-field sensor and displays only an in-focused plane with objects in it. After capturing a confocal image, a de-cluttering process removes the clutter based on blur difference. In preliminary experiments we verified the positive impact of confocal-based background clutter removal on recognition of objects in low resolution and limited dynamic range simulated phosphene images. Using a custom-made multiple-camera system, we confirmed that the concept of a confocal de-cluttered image can be realized effectively using light field imaging.

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2014
Kim J, Jung J-H, Jeong Y, Hong K, Lee B. Real-time integral imaging system for light field microscopy. Opt. Express [Internet]. 2014;22 :10210–10220. Publisher's VersionAbstract
We propose a real-time integral imaging system for light field microscopy systems. To implement a 3D live in-vivo experimental environment for multiple experimentalists, we generate elemental images for an integral imaging system from the captured light field with a light field microscope in real-time. We apply the f-number matching method to generate an elemental image to reconstruct an undistorted 3D image. Our implemented system produces real and orthoscopic 3D images of micro objects in 16 frames per second. We verify the proposed system via experiments using Caenorhabditis elegans.
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Jung J-H, Peli E. Confocal Imaging for Visual Prostheses, in US Army Medical Research and Materiel Command/“Art of the Possible” in Vision Restoration Workshop. Vol [Invited Talk]. Frederick, MD ; 2014.
Jung J-H, Peli E. Multiplexing prism glasses for field expansion in bitemporal hemianopia, in ARVO 2014. Orlando, FL ; 2014.
Jung J-H, Peli E. Configuring multiplexing prism for field expansion of acquired monocular vision and normally sighted, in Vision 2014 (11th International Conference on Low Vision). Melbourne, Australia ; 2014.PDF icon [PDF]
Jung J-H, Peli E. Impact of high power and high incidence angles on peripheral prisms for homonymous hemianopia, in Vision 2014 (11th International Conference on Low Vision). Melbourne, Australia ; 2014.PDF icon [PDF]
Jung J-H. Distortions to visual field expansion with high-power Fresnel prisms. SPIE Newsroom [Internet]. 2014 :DOI: 10.1117/2.1201402.005350. Publisher's VersionPDF icon [PDF]
Jung J-H, Peli E. Impact of high power and angle of incidence on prism corrections for visual field loss. Optical Engineering [Internet]. 2014;53 (6) :061707. Publisher's VersionAbstract
Abstract.  Prism distortions and spurious reflections are not usually considered when prescribing prisms to compensate for visual field loss due to homonymous hemianopia. Distortions and reflections in the high-power Fresnel prisms used in peripheral prism placement can be considerable, and the simplifying assumption that prism deflection power is independent of angle of incidence into the prisms results in substantial errors. We analyze the effects of high prism power and incidence angle on the field expansion, size of the apical scotomas, and image compression/expansion. We analyze and illustrate the effects of reflections within the Fresnel prisms, primarily due to reflections at the bases, and secondarily due to surface reflections. The strength and location of these effects differs materially depending on whether the serrated prismatic surface is placed toward or away from the eye, and this affects the contribution of the reflections to visual confusion, diplopia, false alarms, and loss of contrast. We conclude with suggestions for controlling and mitigating these effects in clinical practice.
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2013
Jung J-H, Kim J, Lee B. Solution of pseudoscopic problem in integral imaging for real-time processing. Opt. Lett. [Internet]. 2013;38 :76–78. Publisher's VersionAbstract
Proposed is a very effective conversion method from pseudoscopic (PS) to orthoscopic elemental image with adjustable depth position of a reconstructed three-dimensional (3D) object for integral imaging (InIm) in real-time. The proposed method is based on the interweaving process in multi-view display (MVD) with consideration of the difference between the ray sampling method of MVD and InIm. The simple transformation matrix formalism enables the real-time conversion from pickup image to display image based on InIm without a PS problem.
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Kim J, Jung J-H, Lee B. Real-time pickup and display integral imaging system without pseudoscopic problem, in Proc. SPIE. 8643, Advances in Display Technologies III. ; 2013 :864303-864303-7. Publisher's Version
Park S-gi, Jung J-H, Jeong Y, Lee B. Depth-fused display with improved viewing characteristics. Opt. Express [Internet]. 2013;21 (23) :28758–28770. Publisher's VersionAbstract
We propose a depth-fused display (DFD) with enhanced viewing characteristics by hybridizing the depth-fusing technology with another three-dimensional display method such as multi-view or integral imaging method. With hybridization, the viewing angle and expressible depth range can be extended without changing the size of the volume of the system compared to the conventional DFD method. The proposed method is demonstrated with experimental system.
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Kim J, Jung J-H, Jang C, Lee B. Real-time capturing and 3D visualization method based on integral imaging. Opt. Express [Internet]. 2013;21 :18742–18753. Publisher's VersionAbstract
We propose a real-time capturing and 3D visualization method based on integral imaging. We applied real-time conversion algorithm to conventional integral imaging pickup system. Gap control method with depth plane adjustment is also applied to improve image quality. Implemented system provides real-time 3D images with ultra high definition resolution in 20 frames per second, and the observer can change depth planes freely. Simulations and experimental results show the validity of proposed system.
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Dupuis M, Jung J-H, Peli E. Calculating Field Expansion and Apical Scotoma Size in Optical Correction for Homonymous Hemianopia, in BMES 2013 Annual meeting. ; 2013 :P-Sat-B-24.
Jung J-H, Peli E. Spurious reflection effects in Fresnel prisms used for visual field expansion , in American Academy of Optometry 2013. ; 2013.
Wooh S, Yoon H, Jung J-H, Lee Y-G, Koh JH, Lee B, Kang YS, Char K. Efficient Light Harvesting with Micropatterned 3D Pyramidal Photoanodes in Dye-Sensitized Solar Cells. Advanced Materials [Internet]. 2013;25 (22) :3111–3116. Publisher's VersionPDF icon [PDF]
2012
Kim J, Jung J-H, Hong J, Yeom J, Lee B. Elemental Image Generation Method with the Correction of Mismatch Error by Sub-pixel Sampling between Lens and Pixel in Integral Imaging. J. Opt. Soc. Korea [Internet]. 2012;16 :29–35. Publisher's VersionAbstract

We propose a subpixel scale elemental image generation method to correct the errors created by finite display pixel size in integral imaging. In this paper, two errors are mainly discussed: pickup-and-display mismatch error and mismatch error between pixel pitch and lens pitch. The proposed method considers the relative positions between lenses and pixels in subpixel scale. Our proposed pickup method calculates the position parameters, generates an elemental image with pixels completely inside the lens, and generates an elemental image with border pixels using a weighted sum method. Appropriate experiments are presented to verify the validity of the proposed method.

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Kim Y, Hong K, Yeom J, Hong J, Jung J-H, Lee YW, Park J-H, Lee B. A frontal projection-type three-dimensional display. Opt. Express [Internet]. 2012;20 :20130–20138. Publisher's VersionAbstract

In a typical auto-stereoscopic three-dimensional display, the parallax barrier or lenticular lens is located in front of the display device. However, in a projection-type auto-stereoscopic display, such optical components make it difficult to display elemental images on the screen or to reconstruct a three-dimensional image, even though a projection-type display has many advantages. Therefore, it is necessary to use a rear projection technique in a projection-type auto-stereoscopic display, despite the fact that this is an inefficient use of space. We propose here a frontal projection-type auto-stereoscopic display by using a polarizer and a quarter-wave retarding film. Since the proposed method uses a frontal projection scheme and passive polarizing components, it has the advantage of being both space saving and cost effective. This is the first report that describes a frontal projection-type auto-stereoscopic display based on a parallax barrier and integral imaging by using a projector. Experimental results that support the proposed method are provided.

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