A pixel mask-based three-dimensional (3-D) display with uniform resolution is proposed. This 3-D display consists of a reflected light source, a pixel mask, a liquid crystal display (LCD) panel, and a lenticular lens. The reflected light source is located on the bottom layer of the proposed 3-D display. It has a reflective structure to improve optical efficiency, so it can make up the brightness loss, which is caused by the pixel mask. The pixel mask is located between the reflected light source and the LCD panel, and is attached on the back surface of the LCD panel. This pixel mask is made of a reflective material, and some transparent areas are etched on it. The pixel mask redefines the pixels of the two-dimensional display panel located in front of it, so the size and location of redefined pixels depend on the transparent area of the pixel mask. The arrangement of the redefined pixels can increase the column numbers of synthetic images. Therefore, the synthetic images can make 3-D images have uniform resolution. A 4-view prototype of this display is developed and the experimental result shows the proposed method can improve resolution uniformity successfully.
In this paper, we propose an optical method based on integral imaging(II) and ptychography to encrypt threedimensional( 3D) information with simple architecture. The 3D scene plaintext is encrypted by a camera array and double-random phase masks via ptychography to generate a series of diffraction intensity patterns as ciphertexts. Then, the decrypting process with ptychographic iteration and II reconstruction is employed to retrieve high-quality 3D images. Since scanning light probes and parameters of II can serve as secret keys that enlarge the key space, and elemental image array generated by the II pickup has redundancy property, the security of encryption scheme can be improved significantly. Also, the decrypted 3D images in our proposed method have high-quality. Preliminary experiments are carried out, and the results demonstrate the feasibility and robustness of our proposed method. Especially, this research is suitable for real large-size 3D scene.
Integral imaging (II) is a good candidate for augmented reality (AR) display, since it provides various physiological depth cues so that viewers can freely change the accommodation and convergence between the virtual three-dimensional (3D) images and the real-world scene without feeling any visual discomfort. We propose two AR 3D display systems based on the theory of II. In the first AR system, a micro II display unit reconstructs a micro 3D image, and the mciro-3D image is magnified by a convex lens. The lateral and depth distortions of the magnified 3D image are analyzed and resolved by the pitch scaling and depth scaling. The magnified 3D image and real 3D scene are overlapped by using a half-mirror to realize AR 3D display. The second AR system uses a micro-lens array holographic optical element (HOE) as an image combiner. The HOE is a volume holographic grating which functions as a micro-lens array for the Bragg-matched light, and as a transparent glass for Bragg mismatched light. A reference beam can reproduce a virtual 3D image from one side and a reference beam with conjugated phase can reproduce the second 3D image from other side of the micro-lens array HOE, which presents double-sided 3D display feature.
An adaptive Cylindrical Lens Array (ACLA) for a 2D/3D switchable display is demonstrated. The ACLA is based on two transparent liquids of different refractive indexes and an elastic membrane. Driving these two liquids to flow can change the shape of the elastic membrane as well as the focal length. In this design, the gravity effect of liquid can be overcome. An ACLA demo for the 2D/3D switchable display is developed. The experimental result shows that the ACLA demo works as a light splitting and 2D/3D switching component of the 2D/3D switchable display effectively and the 2D/3D switchable display is realized.
We propose three dual-view integral imaging (DVII) three-dimensional (3D) displays. In the spatial-multiplexed DVII
3D display, each elemental image (EI) is cut into a left and right sub-EIs, and they are refracted to the left and right
viewing zones by the corresponding micro-lens array (MLA). Different 3D images are reconstructed in the left and right
viewing zones, and the viewing angle is decreased. In the DVII 3D display using polarizer parallax barriers, a polarizer
parallax barrier is used in front of both the display panel and the MLA. The polarizer parallax barrier consists of two
parts with perpendicular polarization directions. The elemental image array (EIA) is cut to left and right parts. The lights
emitted from the left part are modulated by the left MLA and reconstruct a 3D image in the right viewing zone, whereas
the lights emitted from the right part reconstruct another 3D image in the left viewing zone. The 3D resolution is
decreased. In the time-multiplexed DVII 3D display, an orthogonal polarizer array is attached onto both the display
panel and the MLA. The orthogonal polarizer array consists of horizontal and vertical polarizer units and the polarization
directions of the adjacent units are orthogonal. In State 1, each EI is reconstructed by its corresponding micro-lens,
whereas in State 2, each EI is reconstructed by its adjacent micro-lens. 3D images 1 and 2 are reconstructed alternately
with a refresh rate up to 120HZ. The viewing angle and 3D resolution are the same as the conventional II 3D display.
An encrypting three-dimensional (3-D) information system based on integral imaging (II) and multiple chaotic maps is proposed. In the encrypting process, the elemental image array (EIA) which represents spatial and angular information of the real 3-D scene is picked up by a microlens array. Subsequently, R, G, and B color components decomposed by the EIA are encrypted using multiple chaotic maps. Finally, these three encrypted components are interwoven to obtain the cipher information. The decryption process implements the reverse operation of the encryption process for retrieving the high-quality 3-D images. Since the encrypted EIA has the data redundancy property due to II, and all parameters of the pickup part are the secret keys of the encrypting system, the system sensitivity on the changes of the plaintext and secret keys can be significantly improved. Moreover, the algorithm based on multiple chaotic maps can effectively enhance the security. A preliminary experiment is carried out, and the experimental results verify the effectiveness, robustness, and security of the proposed system.
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.
We propose an integral imaging in which the micro-lens array in the pickup process called MLA 1 and the micro-lens array in the display process called MLA 2 have different specifications. The elemental image array called EIA 1 is captured through MLA 1 in the pickup process. We deduce a pixel mapping algorithm including virtual display and virtual pickup processes to generate the elemental image array called EIA 2 which is picked up by MLA 2. The 3D images reconstructed by EIA 2 and MLA 2 don’t suffer any image scaling and distortions. The experimental results demonstrate the correctness of our theoretical analysis.
We propose an integral imaging in which the micro-lens array (MLA) in the pickup process called MLA 1 and the micro-lens array in the display process called MLA 2 have different specifications. The elemental image array called EIA 1 is captured through MLA 1 in the pickup process. We deduce a pixel mapping algorithm including virtual display and virtual pickup processes to generate the elemental image array called EIA 2 which is picked up by MLA 2. The three-dimensional images reconstructed by EIA 2 and MLA 2 do not suffer any image scaling and distortions. The experimental results demonstrate the correctness of our theoretical analysis.
We analyze the effect of aperture width of the parallax barrier on the viewing angle of one-dimensional integral imaging (1-DII) display and propose a 1-DII display that consists of a display panel and a variable parallax barrier. When the variable parallax barrier changes its aperture width, the viewing angle and the optical efficiency of the proposed 1-DII display are compared. The viewing angle is increased by decreasing the aperture width of the variable parallax barrier, while the optical efficiency is increased by increasing the aperture width of the variable parallax barrier.
An integral imaging (II) display is proposed which consists of a display panel and a gradient-aperture pinhole array. The gradient-aperture pinhole array is symmetrical in both horizontal and vertical directions. The leftmost and rightmost pinholes are used to fix the horizontal viewing angle, and the uppermost and nethermost pinholes are used to fix the vertical viewing angle. To increase the optical efficiency, the aperture widths of other pinholes are gradually increased from both sides to the middle in the horizontal and vertical directions, respectively. A prototype of the proposed II display is developed. Its horizontal viewing angle is equal to that of the conventional one, while its optical efficiency is higher than that of the conventional one.