Depth of field analysis for a three-dimensional light-field display based on a lens array and a holographic function screen

Abstract Multilayer light field three-dimensional displays are becoming popular due to their full resolution reconstruction and easy fabrication by utilizing existing display technologies such as liquid crystal display (LCD) panels. However, these displays still suffer from limited performance, achieving low angular resolution, narrow field of view, and small depth of field. One of the recent research ideas focusing on overcoming these limitations is perceptual quality improvement. But, currently introduced methods consider only specific issues/applications such as moiré fringe effect, and near-eye display technology. In this work, the authors propose a novel method of approximating light field data for dual-layered light field display considering the Human Visual and Perceptual System. The authors’ display configuration includes two liquid crystal panels with uniform backlight with no time multiplexing. It is not necessary for LCD panels to be parallel. For a wide field of view configuration, the authors introduce a quadratic penalization term to reduce ghost effects caused by neighboring views. This leads to an improved perceptual approximation of a given light field and increases the possibility of usage in design with a wider field of view configuration.

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Computer Assisted Image Reconstruction of Oligomer Structure

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100092323 ◽

1976 ◽

Vol 34 ◽

pp. 472-473

Author(s):

A.M. Jones ◽

A. Max Fiskin

Keyword(s):

Three Dimensional ◽

Depth Of Field ◽

Computer Assisted ◽

Projection Data ◽

Two Dimensional ◽

Single Particles ◽

Dimensional Reconstruction ◽

Computer Assisted Image ◽

The Fourier Transform ◽

Space Approach

If the tilt of a specimen can be varied either by the strategy of observing identical particles orientated randomly or by use of a eucentric goniometer stage, three dimensional reconstruction procedures are available (l). If the specimens, such as small protein aggregates, lack periodicity, direct space methods compete favorably in ease of implementation with reconstruction by the Fourier (transform) space approach (2). Regardless of method, reconstruction is possible because useful specimen thicknesses are always much less than the depth of field in an electron microscope. Thus electron images record the amount of stain in columns of the object normal to the recording plates. For single particles, practical considerations dictate that the specimen be tilted precisely about a single axis. In so doing a reconstructed image is achieved serially from two-dimensional sections which in turn are generated by a series of back-to-front lines of projection data.

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Cryomicroscopy of crotoxin complex crystals at 400 KV

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100156109 ◽

1989 ◽

Vol 47 ◽

pp. 826-827

Author(s):

Jaap Brink ◽

Wah Chiu

Keyword(s):

Signal To Noise Ratio ◽

3D Structure ◽

Three Dimensional ◽

Carbon Films ◽

Depth Of Field ◽

Basic Subunit ◽

Ewald Sphere ◽

Diffraction Patterns ◽

Complex Crystals ◽

Acidic Subunit

The crotoxin complex is a potent neurotoxin composed of a basic subunit (Mr = 12,000) and an acidic subunit (M = 10,000). The basic subunit possesses phospholipase activity whereas the acidic subunit shows no enzymatic activity at all. The complex's toxocity is expressed both pre- and post-synaptically. The crotoxin complex forms thin crystals suitable for electron crystallography. The crystals diffract up to 0.16 nm in the microscope, whereas images show reflections out to 0.39 nm2. Ultimate goal in this study is to obtain a three-dimensional (3D-) structure map of the protein around 0.3 nm resolution. Use of 100 keV electrons in this is limited; the unit cell's height c of 25.6 nm causes problems associated with multiple scattering, radiation damage, limited depth of field and a more pronounced Ewald sphere curvature. In general, they lead to projections of the unit cell, which at the desired resolution, cannot be interpreted following the weak-phase approximation. Circumventing this problem is possible through the use of 400 keV electrons. Although the overall contrast is lowered due to a smaller scattering cross-section, the signal-to-noise ratio of especially higher order reflections will improve due to a smaller contribution of inelastic scattering. We report here our preliminary results demonstrating the feasability of the data collection procedure at 400 kV.Crystals of crotoxin complex were prepared on carbon-covered holey-carbon films, quench frozen in liquid ethane, inserted into a Gatan 626 holder, transferred into a JEOL 4000EX electron microscope equipped with a pair of anticontaminators operating at −184°C and examined under low-dose conditions. Selected area electron diffraction patterns (EDP's) and images of the crystals were recorded at 400 kV and −167°C with dose levels of 5 and 9.5 electrons/Å, respectively.

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Going Beyond 3-D Imaging: Automated 3-D Montaged image Analysis of Cytological Specimens

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100163873 ◽

1996 ◽

Vol 54 ◽

pp. 282-283

Author(s):

Badrinath Roysam ◽

Hakan Ancin ◽

Douglas E. Becker ◽

Robert W. Mackin ◽

Matthew M. Chestnut ◽

...

Keyword(s):

Image Analysis ◽

Structural Changes ◽

Sampling Methods ◽

Spatial Clustering ◽

Three Dimensional ◽

Field Of View ◽

Cell Counting ◽

Depth Of Field ◽

Tissue Cell ◽

Tissue Organization

This paper summarizes recent advances made by this group in the automated three-dimensional (3-D) image analysis of cytological specimens that are much thicker than the depth of field, and much wider than the field of view of the microscope. The imaging of thick samples is motivated by the need to sample large volumes of tissue rapidly, make more accurate measurements than possible with 2-D sampling, and also to perform analysis in a manner that preserves the relative locations and 3-D structures of the cells. The motivation to study specimens much wider than the field of view arises when measurements and insights at the tissue, rather than the cell level are needed.The term “analysis” indicates a activities ranging from cell counting, neuron tracing, cell morphometry, measurement of tracers, through characterization of large populations of cells with regard to higher-level tissue organization by detecting patterns such as 3-D spatial clustering, the presence of subpopulations, and their relationships to each other. Of even more interest are changes in these parameters as a function of development, and as a reaction to external stimuli. There is a widespread need to measure structural changes in tissue caused by toxins, physiologic states, biochemicals, aging, development, and electrochemical or physical stimuli. These agents could affect the number of cells per unit volume of tissue, cell volume and shape, and cause structural changes in individual cells, inter-connections, or subtle changes in higher-level tissue architecture. It is important to process large intact volumes of tissue to achieve adequate sampling and sensitivity to subtle changes. It is desirable to perform such studies rapidly, with utmost automation, and at minimal cost. Automated 3-D image analysis methods offer unique advantages and opportunities, without making simplifying assumptions of tissue uniformity, unlike random sampling methods such as stereology.12 Although stereological methods are known to be statistically unbiased, they may not be statistically efficient. Another disadvantage of sampling methods is the lack of full visual confirmation - an attractive feature of image analysis based methods.

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