Dual-camera enabled real-time three-dimensional integral imaging pick-up and display.

A new real-time integral imaging pick-up and display method is demonstrated. This proposed method utilizes the dual-camera optical pick-up part to collect 3D information of real scene in real-time without pre-calibration. Elemental images are then provided by a computer-generated integral imaging part and displayed by a projection-type integral imaging display part. The theoretical analysis indicates the method is robust to the camera position deviation, which profits the real-time data processing. Experimental results show that the fully continuous, real 3D scene pick-up and display system is feasible with a throughput of 8 fps in real time. Further analysis predicts that the parallel optimization can be adopted by the proposed method for real-time 3D pick-up and display with a throughput of 25 fps.

Enhancement of depth-of-field in a direct projection-type integral imaging system by a negative lens array.

We propose a method for enhancing depth-of-field, in which the spot size on a marginal depth plane is reduced. This method is implemented in a projection-type integral imaging system using a negative lens array without a diffuser. Numerical simulation results show that the spot size is merely 5.7% of that in a conventional system. Thus, the depth-of-field in the proposed system is enhanced by 17.5 times over that in a conventional system. Optical experiments confirm good agreement between the results and numerical predictions.

Tunable viewing scope of three-dimensional integral imaging.

This article defines the tunable viewing scope (TVS) of three-dimensional integral imaging (3DII) considering the human eye's performance, which could provide a fine viewing effect without flipping or information missing. TVS required by different applications is achieved through an innovative method, attaching the reserved blank to the elemental images. The viewing comfort improvement resulting from TVS is verified by practical experiments, which indicates that it would be promising for future applications of 3DII.

Microaxicave: inverted microaxicon to generate a hollow beam.

We present an inverted structure of microaxicon, called a microaxicave, with periodic micro-conic-cave shapes, to generate circular hollow beams. A microaxicave is fabricated in a quartz substrate with the combination of direct laser writing and inductively coupled plasma etching. The hollow beam generated by the quartz microaxicave is directly recorded with a CCD camera, and the hollow beam is consistent with analysis by the diffraction theory.

Modified optical vortices for encoding topological charges with principal-sidelobe ring relationships.

We study modified optical vortices for encoding topological charges based on radius ratios between principal and the modified first sidelobe rings. The method is immune to harassments from alignment and phase matching between the beams and optical elements. Moreover, it is demonstrated that the radius ratios and their corresponding modulation parameters are independent to wavelength and size of the spiral phase mask.

Explicit relations and optimal parameters for sidelobe suppression in optical vortices with a modified Bessel function.

This paper establishes explicit relations between the radial modulation and the optimal sidelobe expression effect in the Bessel-like modulation technique. It verifies that both central and outer ring areas of the phase plate result in sidelobes in the diffraction pattern, and the corresponding structural dimensions can be determined quantitatively. This approach gives rise to complete sidelobe suppression by taking optimal modulation parameters.

Hexagonal microlens array fabricated by direct laser writing and inductively coupled plasma etching on organic light emitting devices to enhance the outcoupling efficiency.

A hexagonal microlens array directly fabricated on an indium tin oxide glass substrate by the combination of direct laser writing and inductively coupled plasma etching is demonstrated to enhance the outcoupling efficiency of the organic light emitting devices, which can avoid the loss of photons and the mechanical and thermal deformations at the glass/microlenses interface. An atomic force microscope measurement indicates the contour of the fabricated hexagonal microlens is nearly an ideal part of a hemisphere. From the comparison with the operating OLED without a microlens array, the outcoupling efficiency is enhanced more than 40% with the hexagonal microlens array on the glass substrate, and the enhanced emission from the active area of the device with the hexagonal microlens array at the viewing angles from 0 degrees to 40 degrees can clearly be seen.

[Clinical study for postoperative visual acuity in cataract patients with the potential acuity meter].

OBJECTIVE: To study a new domestic potential acuity meter (PAM) for predicting visual acuity (PVA) in patients with cataracts and to compare the results to that measured by PAM-1000 and Lotmar. METHODS: One hundred and fifty cataract eyes were enrolled in this study. PVA was evaluated with three different dioptometers before the surgery and compared to actual best corrected visual acuity (BCVA) obtained two months after the surgery. RESULTS: PVA obtained from domestic PAM correlated well with BCVA. In 56 eyes with non-identical results between PVA and BCVA, 52 eyes were false-negative and 3 eyes were false-positive, indicating that PAM tended to underestimate postoperative BCVA. In severe cataract patients, the correlation between PVA obtained from these three dioptometers and postoperative BCVA was decreased. The identical rates (as compared with postoperative BCVA) for the results obtained from PAM-1000 and Lotmar were 64. 0% and 62. 7%, respectively. CONCLUSIONS: Domestic PAM is relatively reliable for predicting postoperative visual acuity. It is a valuable method in the examination of PVA before the cataract surgery.

Diffraction analysis of blazed transmission gratings with a modified extended scalar theory.

An alternative interpretation of the diffraction of blazed transmission gratings with moderate structure period is proposed according to a modified extended scalar theory (MEST). The diffraction field on the bottom facet of the grating is considered to be the interference of four subfields investigated in the problem of diffraction of a plane wave by an infinite half-plane. It is observed that MEST gives the total field that agrees with rigorous coupled-wave analysis (RCWA), and the result is more reliable than that of extended scalar theory (EST). The MEST is still a ray-optical-based approximation approach, and the region of validity is compared with EST and RCWA.

Illumination system using LED sources for pocket-size projectors.

An illumination system using LED sources for pocket-size projectors is designed. Its color gamut is much larger than the sRGB standard. The maximum theoretical efficiency of this system is 29.98% by non-imaging theory-based calculations. To analyze the system model, 1.5 x 10(6) rays are traced by using the LightTools software. The total light flux that illuminates the digital micromirror device is 44 lm and the American National Standards Institute 13-point uniformity on the surface is 91.55%, -91.15% with a system efficiency of 28.3%. The calculations are in good agreement with the simulation results. The illumination system can be used for personal pocket-size projectors providing a 15-20 in. (38-51 cm) color display with the brightness comparable with a laptop.