In this paper, we propose a color moire pattern reduction method in integral three-dimensional imaging by slanting the lens array. The color moire patterns are examined as varying the slanted angles between the lens array and the display panel for choosing the angles for which the pattern is reduced. However, it is difficult to expect the tendency of the pattern. We simulate the color moire pattern on the assumption of ray optics and find out the angle where the moiré is reduced. With the proposed technique clear three dimensional images can be displayed. The explanation of the proposed method will be provided, and the simulation results will be shown. Finally, experimental results will verify the proposed method.
KEYWORDS: 3D image processing, Integral imaging, Image resolution, LCDs, 3D displays, Liquid crystals, 3D image reconstruction, Imaging arrays, 3D vision, Optical resolution
In this paper, we propose a resolution-enhanced integral imaging with pinhole arrays on liquid crystal (LC) panel. Since
light through a pinhole corresponds to a pixel in 3D image, we electrically move the pinhole arrays on LC panel fast
enough to make after-image effect and display corresponding elemental image synchronously without reducing the 3D
viewing aspect of the reconstructed image. The explanation of the proposed system will be provided and the
experimental results will also be presented.
The three-dimension (3D) to two-dimension (2D) convertibility of display hardware described in this paper is an
essential factor in the commercialization of a 3D display. The liquid crystal (LC), which is a suitable material with its
optical anisotropy and electric properties, is widely used for various 3D/2D convertible display techniques. There are
three kinds of autostreoscopic 3D/2D convertible techniques - the LC lenticular lens, the LC parallax barrier, and
integral imaging. The techniques are on their ways for continuing development and improvement. In this keynote paper
we summarize the principle and status of the techniques.
KEYWORDS: Integral imaging, Imaging systems, 3D image processing, 3D displays, Neodymium, Computing systems, Image enhancement, Information technology, Geometrical optics, LCDs
In this paper, we propose a curved integral imaging system using an additional large-aperture lens. The additional largeaperture
lens provides full-directional curvature effect and improves viewing angle compared with conventional system.
The proposed system has a simple structure due to the use of well-fabricated conventional flat devices without any
modification. A modified computer-generated pickup technique based on ABCD matrix is introduced to calculate
elemental images of the proposed system. To show the usefulness of the proposed system, optical experiments are
carried out and the results are presented. In addition, we analyze the enhanced viewing angle according to the object
location and the limited image size theoretically.
The 3D-2D convertibility is essential for the penetration of the 3D display into the current 2D display market and various methods were proposed to realize it. In this paper, a thin size 3D-2D convertible display using a pinhole array on a polarizer is proposed. The thickness of the proposed system can be below one centimeter. Additionally, the use of a pinhole array on a polarizer enhances the light efficiency of the proposed system in the 2D mode by more than ten times of the 3D mode. This is also essential since the 3D mode is an additional function for a 3D-2D convertible system. As a result, the 2D image quality of the proposed system can be compatible with the existing 2D displays for most aspects. The method is proven by experimental results.
In this paper, we propose an integral imaging with variable image planes using PDLC (polymer-dispersed liquid crystal) films. Parallel layered PDLC films and a projector are adopted as a display system and enable to vary the location of image plane. We can control the transparency of PDLC films electrically and make each film diffuse the projected light successively with different depth from lens array. The explanation of the proposed system is provided and the experimental results are also presented.
KEYWORDS: Image segmentation, Cameras, Motion estimation, Image processing, Data acquisition, Image processing algorithms and systems, Video, Detection and tracking algorithms, 3D displays, 3D image processing
We present an algorithm for stereoscopic conversion of two-dimensional movie encoded in MPEG-2. The stereoscopic
algorithm consists of segmentation process and depth determination process. In the segmentation process, we segment
the image based on the dc information and the motion vector information encoded by MPEG-2. After the segmentation,
depth of each segment is determined by examining the motion vector and the overlapped region of the segment.
KEYWORDS: 3D image processing, Integral imaging, 3D displays, Cameras, Reconstruction algorithms, 3D modeling, Imaging arrays, Image processing, LCDs, Imaging systems
Integral imaging (integral photography) is one of the promising three-dimensional display techniques, which is
composed of pick up and display steps in general. In pick up step, a two-dimensional image array, elemental images that
have three-dimensional information of the object, is obtained. In display step, the elemental images are displayed and
integrated through a lens array for observer to see 3D image. Thus making elemental images in the pick up step is an
important process since the 3D information of the objects is included in the elemental images through this step. In this
paper, we examine the problem of synthesizing elemental images of virtual views from an elemental image using the line
of sight (LOS) algorithm. LOS can handle any number of input images while simultaneously using the information from
all of them, and can be applied in integral imaging to generate elemental images. However, very few images are usually
enough to provide reasonable synthesis quality. The explanation of the proposed algorithm is provided and the results on
real images are presented also.
In spite of significant improvements in three-dimensional (3D) display fields, the commercialization of a 3D-only display system is not achieved yet. The mainstream of display market is a high performance two-dimensional (2D) flat panel display (FPD) and the beginning of the high-definition (HD) broadcasting accelerates the opening of the golden age of HD FPDs. Therefore, a 3D display system needs to be able to display a 2D image with high quality. In this paper, two different 3D-2D convertible methods based on integral imaging are compared and categorized for its applications. One method uses a point light source array and a polymer-dispersed liquid crystal and one display panel. The other system adopts two display panels and a lens array. The former system is suitable for mobile applications while the latter is for home applications such as monitors and TVs.
Recently, a floating display system based on integral imaging (InIm) was proposed. Though the floating display system based on InIm can provide moving picture with great feel of depth to the observer, it has limited expressible depth range because the expressible depth range of InIm is limited. In this paper, the expressible depth range of the floating display system based on InIm is analyzed based on the analysis on the expressible depth range of the InIm. Also, a depth-enhanced floating display system based on InIm is proposed. In the proposed depth-enhanced floating display system based on InIm, the lens array of the InIm is placed at the focal plane of the floating lens. Additionally, the seams on the lens array become less distinct since they are also placed at the focal plane of the floating lens. However, the size of the object changes when the object is out of the overall central depth plane. Thus, the size of objects in elemental image should be rescaled to display correct three-dimensional image.
KEYWORDS: LCDs, 3D displays, 3D image processing, Transmittance, 3D image enhancement, Integral imaging, Stereoscopy, Distortion, Imaging arrays, Imaging systems
In this paper, the authors propose a novel method to construct a wide viewing two-dimension/three-dimension convertible system with two parallel display devices. With changing the role of each display device, it is possible to convert the display mode between 2D and 3D electrically without any mechanical movement. In 2D display mode, the rear display is used as a white light source and the front display device displays the 2D images. In 3D display mode, the rear display device and the lens array construct 3D images, while the front display device displays electrical masks to enhance the viewing angle of the 3D images. Since the basic principle for 2D and 3D display modes are the same as that of LCD display and integral imaging respectively, other improved techniques for both display modes, which will be accomplished with the progress in researches, can be easily applied to the system. The proposed method is also demonstrated by some experimental results.
Integral imaging attracts much attention as an autostereoscopic
three-dimensional display technique for its many advantages. However, the disadvantage of integral imaging is that the expressible depth of three-dimensional image is limited and the image can be displayed only around the central depth plane. This paper proposes a depth- enhanced integral imaging with multiple central depth planes using multilayered display devices. Transparent display devices using liquid crystal are located in parallel to each other and incorporated into an integral imaging system in place of a conventional display device. As a result, the proposed method has multiple central depth planes and permits the limitation of expressible depth to be overcome. The principle of the proposed method is explained, and some experimental results are presented.
Integral imaging (integral photography) is a three-dimensional display technique, first proposed by Lippmann in 1908. Recently the integral imaging attracts much attention as an autostereoscopic three-dimensional display technique for its many advantages. However, the limitation of viewing angle is the primary disadvantage of integral imaging. To overcome the limitation some methods have been proposed. Among them the method that uses a curved lens array has been reported recently. This method widens the viewing angle considerably compared with the conventional method. Generally, in integral imaging each elemental lens has its corresponding area, elemental image region, on the display panel. To prevent the image flipping, the elemental image that exceeds the corresponding area is discarded. Therefore the number of the elemental images is limited. However, in the curved lens array system each elemental image does not exceed the corresponding area. It owes the curved structure and this characteristic widens the viewing angle.
In this paper, we will examine the proposed integral imaging system using a curved lens array and analyze of the representative viewing parameters; viewing angle, image depth, image size, etc. for the curved lens array system. The viewing region, in which the three-dimensional image can be displayed with wide-viewing angle, is closely related with image depth and the corresponding viewing angle of the curved lens array system.
In this paper, we propose a wide-viewing-angle three-dimensional integral imaging using a curved screen and a curved lens array. Elemental images are projected to the curved screen. Incorporation of the curved screen and the curved lens array instead of a conventional flat display panel and a flat lens array expands the viewing angle remarkably. In addition adopting barriers between a curved lens array and a curved screen eliminates the flipped images effectively without affecting the viewing angle. The principle of the proposed system is explained and the experimental results about the viewing angle of real and virtual images are also presented.
In three-dimensional display based on integral imaging, the resolution of the elemental images is a major factor that determines the resolution of the integrated three-dimensional image. Though the pixel pitch of the display panel imposes fundamental limit on the resolution of the elemental images, it is often not fully utilized due to low resolution of the pickup devices. In this paper, we propose a method to enhance the resolution of the elemental images. The proposed method estimates the sub-pixel disparity of the elemental images and generates high resolution elemental images using multiple low resolution elemental images. We explain the principle and verify it by simulation and experimental results.
Detecting depth information from a pickup image of integral imaging is of great importance since it is the first step for providing integral imaging systems with some flexibility against various system specifications and display environment. One problem of the depth extraction in the integral imaging is that the gap between the lens array and the elemental image plane cannot be determined exactly since the desired value depends on the object depth itself. Moreover, an object to be picked up is preferred to be located close to the lens array to ensure sufficient resolution in the elemental image and the detected depth profile, which makes the gap deviate too far from the focal length of the lens array, and thus disturbs exact depth extraction. In this paper, we propose a depth extraction method using a uniaxial crystal in addition to the lens array. The proposed system can detect the depth without prior knowledge of gap between the lens array and the elemental image plane. We explain the principle and verify it by simulation and experimental results.
Depth-enhanced integral three-dimensional (3D) imaging using different optical path lengths and polarization selective mirror pair is proposed. In this approach, the enhancement of image depth is achieved by repositioning two types of elemental image planes, thus effectively two central depth planes are obtained. The system makes use of two-arm-structure that has different optical path lengths and polarization selective mirrors. The primary advantage of our proposed method is that we can observe 3D images that maintain some level of viewing resolution with large depth difference without any mechanical moving part. We experimentally demonstrated our proposal by reconstructing real and virtual images with the depth difference of 140 mm successfully.
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