Cheng-Gao Luo

Analysis of the depth of field of integral imaging displays based on wave optics

In this paper, we analyze the depth of field (DOF) of integral imaging displays based on wave optics. With considering the diffraction effect, we analyze the intensity distribution of light with multiple micro-lenses and derive a DOF calculation formula for integral imaging display system. We study the variations of DOF values with different system parameters. Experimental results are provided to verify the accuracy of the theoretical analysis. The analyses and experimental results presented in this paper could be beneficial for better understanding and designing of integral imaging displays.

Crosstalk-Free Integral Imaging Display With Wide Viewing Angle Using Periodic Black Mask

Two of the main limitations of integral imaging are the crosstalk and the narrow viewing angle. In this paper, a crosstalk free integral imaging display with wide viewing angle is proposed. A layer of transparent high refractive index packing medium is padded onto a display panel to enhance the viewing angle, and then a periodic black mask is coated on the top surface of the medium layer to avoid the crosstalk and image flipping. The proposed integral imaging display can provide us with crosstalk free 3D images within a wide viewing angle. Experiments are carried out and good results finally verify the feasibility of the proposed method.

Dual-view integral imaging three-dimensional display

In this paper, we propose a dual-view integral imaging (DVII) three-dimensional (3D) display that presents different 3D images in the left and right viewing directions simultaneously. The DVII 3D display consists of a display panel and a microlens array, and its elemental image array (EIA) is composed of two sub-EIAs. The sub-EIAs captured for two different 3D scenes are responsible for two different 3D images in the left-view and right-view integral imaging 3D displays, respectively. A prototype of the DVII 3D display using a pinhole array is developed, and good results are obtained.

Tilted elemental image array generation method for moiré-reduced computer generated integral imaging display.

In this paper, we propose a tilted elemental image array generation method for computer generated integral imaging display with reduced moiré patterns. The pixels of the tilted elemental image array are divided into border pixels and effective pixels. According to the optimal tilted angle, the effective pixels are arranged with uniform arrangement. Also, a pixel mapping method is proposed. Appropriate experiments are carried out and the experimental results show that not only the color moiré patterns are reduced remarkably, but also the resolution of the reconstructed 3D images are improved through the proposed method.

Depth Calculation Method of Integral Imaging Based on Gaussian Beam Distribution Model

In this paper, we propose a concept of the optimal viewing distance range and a depth calculation method of integral imaging. By considering the light emanating from a single elemental image point as a Gaussian beam, we analyze the integral imaging depth range and deduce the depth calculation formulas in different display modes. Experiments in focused mode were carried out, and good results finally confirmed the feasibility of the proposed method.

Dual-view integral imaging 3D display using polarizer parallax barriers

We propose a dual-view integral imaging (DVII) 3D display using polarizer parallax barriers (PPBs). The DVII 3D display consists of a display panel, a microlens array, and two PPBs. The elemental images (EIs) displayed on the left and right half of the display panel are captured from two different 3D scenes, respectively. The lights emitted from two kinds of EIs are modulated by the left and right half of the microlens array to present two different 3D images, respectively. A prototype of the DVII 3D display is developed, and the experimental results agree well with the theory.

Three-Dimensional Terahertz Coded-Aperture Imaging Based on Single Input Multiple Output Technology

As a promising radar imaging technique, terahertz coded-aperture imaging (TCAI) can achieve high-resolution, forward-looking, and staring imaging by producing spatiotemporal independent signals with coded apertures. In this paper, we propose a three-dimensional (3D) TCAI architecture based on single input multiple output (SIMO) technology, which can reduce the coding and sampling times sharply. The coded aperture applied in the proposed TCAI architecture loads either purposive or random phase modulation factor. In the transmitting process, the purposive phase modulation factor drives the terahertz beam to scan the divided 3D imaging cells. In the receiving process, the random phase modulation factor is adopted to modulate the terahertz wave to be spatiotemporally independent for high resolution. Considering human-scale targets, images of each 3D imaging cell are reconstructed one by one to decompose the global computational complexity, and then are synthesized together to obtain the complete high-resolution image. As for each imaging cell, the multi-resolution imaging method helps to reduce the computational burden on a large-scale reference-signal matrix. The experimental results demonstrate that the proposed architecture can achieve high-resolution imaging with much less time for 3D targets and has great potential in applications such as security screening, nondestructive detection, medical diagnosis, etc.

Extended depth-of-field in integral-imaging pickup process based on amplitude-modulated sensor arrays

Abstract. We implement a depth-of-field (DOF) extending pickup experiment of integral imaging based on amplitude-modulated sensor arrays (SAs). By implementing the amplitude-modulating technique on the SA in the optical pickup process, we can modulate the light intensity distribution in the imaging space. Therefore, the central maximum of the Airy pattern becomes narrower and the DOF is enlarged. The experimental results obtained from the optical pickup process and the computational reconstruction process demonstrate the effectiveness of the DOF extending method. We present that the DOF extending pickup method is more suitable for enhancing the DOF of three-dimensional scenes with small depth ranges.

Study on coding strategies for radar coded-aperture imaging in terahertz band

Abstract. Motivated by the principle of coded-aperture imaging and microwave radar coincidence imaging (RCI), terahertz radar coded-aperture imaging (RCAI) is proposed to obtain high-resolution, forward-looking, and staring imaging. The terahertz RCAI method resolves target scatterers using the correlation processing of the modulated echoes and the reference signal matrix. This process is similar to the basic principle of RCI. To investigate the coding strategies of terahertz RCAI, this study derives three signal models describing operation with the coded aperture placed separately in the transmitting terminal and the receiving terminal and in both of them simultaneously. Furthermore, coding strategies are categorized according to coded-aperture placement and encoded signal, including amplitude modulation and phase modulation. In addition, qualitative and quantitative analysis methods are introduced to describe the resolving ability of terahertz RCAI. Numerical simulations are performed to analyze and compare the performance on different coding strategies. These analyses can provide constructive guidelines for the design of terahertz RCAI systems.

Integral Imaging Pickup Method With Extended Depth-of-Field by Gradient-Amplitude Modulation

One of the major drawbacks of the three-dimensional (3D) integral imaging (II) is the limited depth-of-field (DOF). One approach to enhance the DOF is applying the amplitude-modulating method on the microlens arrays. However, the conventional amplitude-modulating methods usually suffer some collateral effects such as lateral resolution reductions or contrast reversals. In this paper, we propose a gradient-amplitude-modulating (GAM) method to enhance the DOF of the II pickup system when recording large-depth 3D scenes. This method is practical and not accompanied by any obvious lateral resolution deteriorations or contrast reversals. Experimental results obtained from the optical pickup process and computational reconstruction process finally demonstrate the feasibility of the proposed method.