Despite the high output characteristics of holographic optical elements (HOEs), there are still no affordable holographic AR glasses that combine qualities such as a wide field of view (FOV) and a large eyebox (EB). In this study, we propose an architecture for holographic augmented reality glasses that covers both needs. Our solution is based on the combination of an axial HOE with a directional holographic diffuser (DHD) illuminated by a projector. A transparent-type DHD redirects the light from the projector, increasing the angular aperture of the image beams and providing a large EB. A reflection-type axial HOE redirects the light, transforming the spherical beams into parallel ones and providing a wide FOV for the system. The main feature of our system is the coincidence of the DHD position with the planar intermediate image of the axial HOE. This unique condition makes the system free of off-axial aberrations and ensures high output characteristics. The proposed system has a horizontal FOV of 60 deg and an EB width of 10 mm. We used modeling and a prototype to prove our investigations.
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http://dx.doi.org/10.1364/AO.478529 | DOI Listing |
Children (Basel)
May 2023
Department of Human Biology, Wroclaw University of Health and Sport Sciences, 51-612 Wroclaw, Poland.
Unlabelled: Children with weakened axial muscle tone face various problems every day. One is maintaining a stable body posture, which limits their participation in activities and games with peers. The study aimed to assess balance parameters in children with weakened axial muscle tone who underwent sensory integration therapy (SI).
View Article and Find Full Text PDFDespite the high output characteristics of holographic optical elements (HOEs), there are still no affordable holographic AR glasses that combine qualities such as a wide field of view (FOV) and a large eyebox (EB). In this study, we propose an architecture for holographic augmented reality glasses that covers both needs. Our solution is based on the combination of an axial HOE with a directional holographic diffuser (DHD) illuminated by a projector.
View Article and Find Full Text PDFBrain Stimul
October 2021
School of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea; KAIST Institute for Health Science and Technology (KIHST), Daejeon, 34141, Republic of Korea; KAIST Institute for NanoCentury (KINC), Daejeon, 34141, Republic of Korea. Electronic address:
Background: Low-intensity transcranial focused ultrasound stimulation is a promising candidate for noninvasive brain stimulation and accurate targeting of brain circuits because of its focusing capability and long penetration depth. However, achieving a sufficiently high spatial resolution to target small animal sub-regions is still challenging, especially in the axial direction.
Objective: To achieve high axial resolution, we designed a dual-crossed transducer system that achieved high spatial resolution in the axial direction without complex microfabrication, beamforming circuitry, and signal processing.
Phys Med Biol
October 2017
Department of Electronics and Information Systems, MEDISIP, Ghent University-iMinds Medical IT-IBiTech, De Pintelaan 185 block B, B-9000 Ghent, Belgium. Department of Biomedical Engineering, University of California-Davis, One Shields Avenue, CA 95616, United States of America.
The goal of this simulation study is the performance evaluation and comparison of six potential designs for a time-of-flight PET scanner for pediatric patients of up to about 12 years of age. It is designed to have a high sensitivity and provide high-contrast and high-resolution images. The simulated pediatric PET is a full ring scanner, consisting of 32 × 32 mm monolithic LYSO:Ce crystals coupled to digital silicon photomultiplier arrays.
View Article and Find Full Text PDFNeurosurgery
January 2000
Biomedical Laboratory, Kent Ridge Digital Laboratories, Singapore.
Objective: To report our experience with preoperative neurosurgical planning in our stereoscopic virtual reality environment for 21 patients with intra- and extra-axial brain tumors and vascular malformations.
Methods: A neurosurgical planning system called VIVIAN (Virtual Intracranial Visualization and Navigation) was developed for the Dextroscope, a virtual reality environment in which the operator reaches with both hands behind a mirror into a computer-generated stereoscopic three-dimensional (3-D) object and moves and manipulates the object in real time with natural 3-D hand movements. Patient-specific data sets from multiple imaging techniques (magnetic resonance imaging, magnetic resonance angiography, magnetic resonance venography, and computed tomography) were coregistered, fused, and displayed as a stereoscopic 3-D object.
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