Imitating micro-lens array for integral imaging

<正>Integral imaging is a true,three-dimensional(3D) display technology that captures and reconstructs 3D scenes using two-dimensional(2D) micro-lens arrays.The manufacturing technique of micro-lens arrays is complicated and expensive,thus limiting the application of the technology.An imitating micro-lens array for integral imaging is presented in this letter.Imitating micro-lens array is composed of a cheap lenticular lens and a parallax barrier.The relationship of the parameters of the imitating micro-lens array is analyzed and the parameter formulae are deduced.The arrangement of pixels under a cell of the imitating micro-lens array is presented.The imitating micro-lens array is simulated using ASAP software,and the results prove that the designed imitating micro-lens array is effective.A 3D scene is reconstructed on a 3D display that consists of the imitating micro-lens array and a 17-inch flat panel display.     

直接积分法研究电子光学成像系统的时间像差理论

提出了计算动态电子光学成像系统时间像差系数的新方法——直接积分法.以阴极面逸出的轴向电子初能为ε_z1（0≤ε_z1≤ε_0max）的近轴电子 轨迹为比较 基准,给出了时间像差的定义,详细叙述了直接积分法并给出求解动态电子光学成像系统时 间像差系数的积分表达式.τ变分法求得的二级几何时间像差系数必须求解微分方程, 而直接积分法求得的二级几何时间像差系数全部以积分形式表示,仅需进行积分运算,更适 用于成像系统的实际计算与设计. 关键词： 电子光学成像系统 阴极透镜 动态电子光学 时间像差理论     

Modified smart pixel mapping method for displaying orthoscopic 3D images in integral imaging

In this paper, we propose a modified smart pixel mapping (MSPM) method for displaying orthoscopic three-dimensional (3D) images with a function of depth control in integral imaging system. In the proposed MSPM, the depth-converted elemental image array (EIA) is obtained through the pixel mapping process and the image interpolation technique. The proposed method gives us the depth conversion at distances different from the position of 3D object and provides various types of EIAs using only an original EIA for orthoscopic images. To show the usefulness of the proposed method, we carry out the preliminary experiments and present the experimental results.     

An affinity theorem for integral imaging equations

It is shown that any integral imaging equation whose solutions are known can be used to generate a class of solvable integral equations via an affinity transformation.     

集成成像同名像点三维形貌获取方法

为了实现被动式三维形貌获取技术, 首先利用光线追迹方法从理论上对集成成像阵列式多角度图像获取技术进行了深入分析;对于元素图像阵列中同名像点的间距和三维物点位置之间的关联性进行了理论分析;在此基础上提出了集成成像同名像点三维形貌获取方法。实验结果显示, 本文提出的集成成像同名像点三维形貌获取技术能够获取三维物体的三维形貌和任意三维点的空间坐标。定量实验结果显示获取结果相对误差小于5%, 证实了本文提出的基于集成成像同名像点三维形貌获取技术能够实现三维信息的光学获取。     

Three-dimensional polarimetric integral imaging

A three-dimensional (3D) polarimetric image sensing and display technique based on integral imaging is proposed. Three-dimensional polarization distribution of reflected light from a 3D object can be measured as elemental image arrays by a rotating linear polarizer. After the measurement of the polarization of the 3D object, the 3D polarimetric object can be reconstructed optically by displaying the polarization-selected elemental images in spatial light modulators with two quarter-wave plates. Experimental demonstration of 3D polarimetric imaging of a 3D object attached to two orthogonal linear polarizers is presented. To the best of our knowledge, this is the first report on 3D polarimetric sensing imaging and 3D optical reconstruction by integral imaging.     

Continuous imaging space in three-dimensional integral imaging

We report an integral imaging method with continuous imaging space. This method simultaneously reconstructs real and virtual images in the virtual mode, with a minimum gap that separates the entire imaging space into real and virtual space. Experimental results show that the gap is reduced to 45% of that in a conventional integral imaging system with the same parameters.     

Reflection-type integral imaging scheme for displaying three-dimensional images

A reflection-type integral imaging scheme for displaying three-dimensional images is proposed. By use of a concave mirror array instead of a lens array, three-dimensional images are integrated in the form of a reflection type, and the experimental results are demonstrated. This scheme can readily be applied to a large integral imaging system by use of a beam projector that is located at a distance from the mirror-array plane.     

Three-dimensional synthetic aperture integral imaging

We propose synthetic aperture integral imaging, in which an effectively enlarged aperture (or field of view) is obtained by movement of small integral imaging system. This system substantially increases the field of view and the viewing resolution. The feasibility of our approach is experimentally demonstrated. To the best of our knowledge, this is the first time the synthetic aperture technique has been applied to three-dimensional integral imaging.     

Three-dimensional integral imaging of micro-objects

We propose a method for displaying micro-objects in space that is based on three-dimensional (3D) integral imaging, in which elemental images are calculated from a two-dimensional sampling of the optical field along different depths by use of confocal scanning microscopy. Experimental results are presented to demonstrate that a uniformly magnified 3D biological specimen can be displayed in space, and thus integral imaging can be used for 3D display of confocal microscopy. To the best of our knowledge, this is the first report of 3D integral imaging of (semitransparent) micro-objects.     

A path integral method for data assimilation

Described here is a path integral, sampling-based approach for data assimilation, of sequential data and evolutionary models. Since it makes no assumptions on linearity in the dynamics, or on Gaussianity in the statistics, it permits consideration of very general estimation problems. The method can be used for such tasks as computing a smoother solution, parameter estimation, and data/model initialization.Speedup in the Monte Carlo sampling process is essential if the path integral method has any chance of being a viable estimator on moderately large problems. Here a variety of strategies are proposed and compared for their relative ability to improve the sampling efficiency of the resulting estimator. Provided as well are details useful for its implementation and testing.The method is applied to a problem in which standard methods are known to fail, an idealized flow/drifter problem, which has been used as a testbed for assimilation strategies involving Lagrangian data. It is in this kind of context that the method may prove to be a useful assimilation tool in oceanic studies.     

Orthoscopic integral imaging display by use of the computational method based on lenslet model

In this paper, we propose a computational depth conversion method based on the lenslet model to display the orthoscopic 3D images in 3D integral imaging display. The proposed method permits the synthesis of elemental images for the orthoscopic 3D images at any arbitrary position without any restrictions and requires no additional procedure during the depth conversion process. Due to the lenslet model involved in the depth conversion procedure, the proposed method can broaden the flexibility of 3D image reconstruction in the integral imaging display system. We carry out the preliminary experiments to prove the feasibility of the proposed method. The experimental results reveal that the proposed method is an effective depth conversion method that allows the reconstruction of the orthoscopic 3D images at any arbitrary position.     

Three-dimensional image correlator using fast computational integral imaging reconstruction method based on pixel-to-pixel mapping

In this paper, a three-dimensional (3D) image correlator using a fast computational integral imaging reconstruction (CIIR) method based on a pixel-to-pixel mapping is proposed. In order to implement the fast CIIR method, we replace the magnification process in the conventional CIIR by a pixel-to-pixel mapping. The proposed fast CIIR method reconstructs two sorts of plane images; a plane image whose quality is sufficient, and a dot pattern plane image insufficient to view. This property is very useful to enhance the performance of a CIIR-based image correlator. Thus, we apply the fast CIIR method to a CIIR-based image correlator. To show the feasibility of the proposed method, some preliminary experiments on both pattern correlation and computational cost are carried out, and the results are presented. Our experimental results indicate that the proposed image correlator is superior to the previous method in terms of both correlation performance and complexity.     

Viewing-angle-enhanced integral imaging by lens switching

In spite of the many advantages of integral imaging, its narrow viewing angle has been a disadvantage. We propose a method to enhance the viewing angle of integral imaging by opening and shutting each lens in the array (i.e., the elemental lenses) sequentially. We prove our idea by using a mask that has a pattern of an on-off vertical array of apertures. Moving the mask prevents the aliasing of a neighboring lens. Thus image overlap or image flipping is reduced and the viewing angle of the system is increased.     

Computational integral imaging reconstruction method of 3D images using pixel-to-pixel mapping and image interpolation

In this paper, we propose a novel computational integral imaging reconstruction (CIIR) method to improve the visual quality of the reconstructed images using a pixel-to-pixel mapping and an interpolation technique. Since an elemental image is magnified inversely through the corresponding pinhole and mapped on the reconstruction output plane based on pinhole-array model in the conventional CIIR method, the visual quality of reconstructed output image (ROI) degrades due to the interference problem between adjacent pixels during the superposition of the magnified elemental images. To avoid this problem, the proposed CIIR method generates dot-pattern ROIs using a pixel-to-pixel mapping and substitutes interpolated values for the empty pixels within the dot-pattern ROIs using an interpolation technique. The interpolated ROIs provides a much improved visual quality compared with the conventional method because of the exact regeneration of pixel positions sampled in the pickup process without interference between pixels. Moreover, it can enable us to reduce a computational cost by eliminating the magnification process used in the conventional CIIR. To confirm the feasibility of the proposed system, some experiments are carried out and the results are presented.     

One-dimensional integral imaging based on parallax barrier

One-dimensional integral imaging (1DII) which only has horizontal disparity is a practical solution of high resolution in the vertical direction, low-cost, easy-viewable three-dimensional (3D) display. A 1DII based on a parallax barrier is proposed in this paper. The 1DII consists of a parallax barrier and a display panel. The operation principle and parameter calculation of the 1DII are described in detail. Two prototypes of the proposed 1DII and conventional 1DII based on a lenticular lens array are developed. The proposed 1DII improves the quality of the 3D image and provides larger viewing angle than that based on a lenticular lens array, and it is simpler and has lower cost than that based on a lenticular lens array.     

Optimization of the lens-array structure for performance improvement of integral imaging

The seemingly inherent deficiencies of integral imaging systems-in particular, the depth of field limitation-are, in this Letter, partly resolved by using an irregular lens array, where each lens is either rotated or displaced from its original position in the conventional flat lens array. It is shown that having an array of lenses in the integral imaging system has some sort of redundancy that could be exploited to improve the quality of the image formation. The needed rotation or displacement of constituent lenses in the array is found by using a meticulous optimization algorithm, which tries to evenly distribute the optical rays emanating from each of the lenses to form the final image.     

A spectral boundary integral method for flowing blood cells

A spectral boundary integral method for simulating large numbers of blood cells flowing in complex geometries is developed and demonstrated. The blood cells are modeled as finite-deformation elastic membranes containing a higher viscosity fluid than the surrounding plasma, but the solver itself is independent of the particular constitutive model employed for the cell membranes. The surface integrals developed for solving the viscous flow, and thereby the motion of the massless membrane, are evaluated using an O(NlogN)$O(N\log N)$ particle-mesh Ewald (PME) approach. The cell shapes, which can become highly distorted under physiologic conditions, are discretized with spherical harmonics. The resolution of these global basis functions is, of course, excellent, but more importantly they facilitate an approximate de-aliasing procedure that stabilizes the simulations without adding any numerical dissipation or further restricting the permissible numerical time step. Complex geometry no-slip boundaries are included using a constraint method that is coupled into an implicit system that is solved as part of the time advancement routine. The implementation is verified against solutions for axisymmetric flows reported in the literature, and its accuracy is demonstrated by comparison against exact solutions for relaxing surface deformations. It is also used to simulate flow of blood cells at 30% volume fraction in tubes between 4.9 and 16.9 μm in diameter. For these, it is shown to reproduce the well-known non-monotonic dependence of the effective viscosity on the tube diameter.     

Wavelet method for solving integral equations of simple liquids

A new algorithm is developed to solve integral equations for simple liquids. The algorithm is based on the discrete wavelet transform of radial distribution functions. The Coifman 2 basis set is employed for the wavelet treatment. Using the algorithm, we have calculated structural and thermodynamic properties of a Lennard–Jones fluid in a wide range of energy and size parameters of the fluid.