Lenticular Sheet Research Articles

Compensation of lens manufacturing errors and inhomogeneities by filtering view images in three-dimensional lenticular displays.

For a multiview autostereoscopic three-dimensional display based on the lenticular lens, the manufacturing errors and inhomogeneities of the lenticular sheet can deteriorate the view image quality. A calibration method is proposed by filtering the pixel mapping of all view images. Each view is first sequentially turned on to show a white test image, and the intensity distribution of every view will be analyzed. Then individual filter functions are derived and applied to the corresponding view images to correct the subpixel value. Experimental results show that the proposed method can solve view image loss and significantly improve the quality of stereoscopic images.

Large-screen multi-view 3D display

A multi-view 3D display system consisting of modules for capturing three-dimensional objects, image processing (creating 3D image files), and a display screen for displaying 3D images has been developed. Large screens using multiple projectors to improve performance, such as view resolution, have been created. A prototype of the device was built using four projectors equivalent to 4K resolution, and 34-inch 3D images with a viewing angle of 35 degrees and a large depth were demonstrated. The display screens are designed using a vertically aligned lenticular sheet and a scattering layer that evenly diffuses light in both vertical and horizontal directions. We have experimentally demonstrated the ability to “look around” an object on the screen.

Study on the Reduction Effect of Stereo Depth Caused by Lens Aberration in Lenticular-Based Autostereoscopic Displays

Autostereoscopic displays employing lenticular sheets have broad applications due to the high transmittance of lenticular sheet. However, due to the restriction of lens array design and processing, the imperfect image of lenses can reduce the quality experience of autostereoscopic displays. Stereo depth is one of the qualities of experience parameters, which relates to the three-dimensional effect. Therefore, to quantize the reduction effect of stereo depth caused by lens aberration is of great value. In this paper, we implement a binocular model of an autostereoscopic display system with lens array to analyze this effect, which is different from the previously used monocular model. Two receivers in the positions of viewer’s eyes are set on the viewing plane, and a similar factor is defined to evaluate the difference of light spots perceived by the two receivers. When the similar factor exceeds a certain value, the two spots cannot be fused in the brain, thus restricting the perceived stereo depth. Both in simulation and experiment, a sudden decrease of the similar factor is observed when the viewing angle exceeds 16°. In the subjective experiment, all the sixteen viewers feel a sudden decrease of stereo depth when the viewing angle exceeds 16°, which further verifies the validity of the model. The model and the method are significant for improving the viewing experience of autostereoscopic displays and providing a guidance on autostereoscopic display system designing.

Autostereoscopic three-dimensional display with high resolution and low cross talk using a time-multiplexed method

We propose an autostereoscopic three-dimensional (3-D) display using a time-multiplexed method. This display consists of a two-dimensional (2-D) display panel, a time-multiplexed liquid crystal parallax barrier (LCPB), and a lenticular sheet. The 2-D display provides four-view synthetic images. The time-multiplexed LCPB located in front of the 2-D display panel is used to project parallax images in different spatial directions. With the time-multiplexed method, 3-D pixels with different locations can be provided for a time sequence, allowing a high 3-D resolution to be achieved. The lenticular lens is located between the 2-D display panel and the LCPB. Because of congregating ray functions of the lenticular sheet, cross talk can be effectively reduced. We describe the principle and parameter calculations for the prototype of the proposed display. Compared with the conventional autostereoscopic 3-D display, the proposed display has a higher resolution and minimal cross talk.

Subpixel Multiplexing Method for 3D Lenticular Display

Three-dimensional display technologies based on lenticular sheet overlaid onto spatial light modulator screen have been studied for decades. However, the quality of these displays still suffers from insufficient number of views and zone-jumping between views. We present herein a subpixel multiplexing method in this paper. We propose to split mapping and alignment into two separate tasks, processed in parallel threads. Alignment thread deals with the task of computing the geometrical relationship between lenticular sheet and Liquid Crystal Display (LCD) panel for multiplexing. Afterwards, we conduct the multiplexing procedure through a box-constrained integer least squares algorithm. After multiplexing, each subpixel aggregated on the lenticular sheet is a multiplexing one that mixes up a number of subpixels in local region on the LCD plane. As a result, we multiplex subpixels on the synthetic image up to 27 views with a resolution of $1080 \times 1920$ and the rendering speed is 73.34 frames per second (fps).

P‐75: Autostereoscopic 3D Projection Display with Low Crosstalk

In order to achieve high quality and large screen autostereoscopic three‐dimensional (3D) display, We propose an autostereoscopic three‐dimensional display based on a parallax barrier and a lenticular sheet. It is an effective approach to realize large size 3D images and low crosstalk. A 50‐inch prototype which presents good stereoscopic images with low crosstalk is developed.

Aberration analyses for improving the frontal projection three-dimensional display.

The crosstalk severely affects the viewing experience for the auto-stereoscopic 3D displays based on frontal projection lenticular sheet. To suppress unclear stereo vision and ghosts are observed in marginal viewing zones(MVZs), aberration of the lenticular sheet combining with the frontal projector is analyzed and designed. Theoretical and experimental results show that increasing radius of curvature (ROC) or decreasing aperture of the lenticular sheet can suppress the aberration and reduce the crosstalk. A projector array with 20 micro-projectors is used to frontally project 20 parallax images one lenticular sheet with the ROC of 10 mm and the size of 1.9 m × 1.2 m. The 3D image with the high quality is experimentally demonstrated in both the mid-viewing zone and MVZs in the optimal viewing plane. The 3D clear depth of 1.2m can be perceived. To provide an excellent 3D image and enlarge the field of view at the same time, a novel structure of lenticular sheet is presented to reduce aberration, and the crosstalk is well suppressed.

An Autostereoscopic Device for Mobile Applications Based on a Liquid Crystal Microlens Array and an OLED Display

In recent years, many experimental and theoretical research groups worldwide have actively worked on demonstrating the use of liquid crystals (LCs) as adaptive lenses for image generation, waveform shaping, and non-mechanical focusing applications. In particular, important achievements have concerned the development of alternative solutions for 3D vision. This work focuses on the design and evaluation of the electro-optic response of a LC-based 2D/3D autostereoscopic display prototype. A strategy for achieving 2D/3D vision has been implemented with a cylindrical LC lens array placed in front of a display; this array acts as a lenticular sheet with a tunable focal length by electrically controlling the birefringence. The performance of the 2D/3D device was evaluated in terms of the angular luminance, image deflection, crosstalk, and 3D contrast within a simulated environment. These measurements were performed with characterization equipment for autostereoscopic 3D displays (angular resolution of 0.03 $^{\circ}$ ).

Auto-Stereoscopic 3D Video Conversation System Based on an Improved Eye Tracking Method

An auto-stereoscopic 3D video conversation system is demonstrated with an improved eye-tracking method based on a lenticular sheet and two cameras. The two cameras are used to get stereoscopic picture pairs and addressed the viewers position by an Improved Eye Tracking Method. The computer combines the stereoscopic picture pairs with different masks graphic processing unit. Low crosstalk correct stereoscopic video pairs for the end-to-end commutation are achieved.

Analysis of a color-matching backlight system using a blazed grating and a lenticular lens array

A high efficiency LCD employing a color-matching backlight system that consists of a collimation lenticular lens sheet, a blazed grating, and a focusing lenticular lens array is proposed and analyzed. The RGB lights that are collimated and dispersed from the collimation lenticular lens sheet and the blazed grating are incident on the RGB color filters by the focusing lenticular lens array. The color-matched transmittance was increased 183% and 121% for divergence angles of 2° and 11°, respectively, compared to a conventional backlight that does not use a blazed grating. The design, simulation, and experimental results for the prototype color-matching backlight system are presented.

An Autostereoscopic 3D Projection Display Based on a Lenticular Sheet and a Parallax Barrier

Three-dimensional (3D) projection display is an effective approach to realize large size 3D images with high resolution. An autostereoscopic 3D projection display is proposed. It consists of four projectors, a projection screen, a lenticular sheet and a parallax barrier. Operation principle and calculation equations are described in details and the parallax images are corrected by the means of homography. A 50-inch autostereoscopic 3D projection display prototype is developed and it presents good stereoscopic images. The normalized luminance distributions of the viewing zones are measured, and the results agree well with the designed values. Compared with the conventional autostereoscopic 3D projection display based on two parallax barriers, the proposed prototype has much higher brightness.

58.3: Pixel Design for Improved 3D TV with One‐Dimensional Integral‐Imaging Method

AbstractThe one‐dimensional (horizontal parallax only) integral imaging (1D‐II) method realizes a natural and easy‐to‐view 3D display. The 1D‐II method is a display system that has a lenticular sheet in front of a high‐resolution LCD. The use of vertical lenticular sheet is known to provide an excellent spatial frequency of 3D images. For the development of autostereoscopic 3D display with a vertical lenticular sheet, we designed new LCD pixels that can suppress moiré artifacts without reducing opening ratio of pixels. By virtue of this design, we successfully put an easy‐to‐view 3D TV into practical use.

17.1: Hardware and Software Technologies for Glasses‐Free 3D TVs and PCs

AbstractWe have developed several technologies for glasses‐free 3D displays to produce a clear 3D image and offer an attractive application. Hardware technologies such as one‐dimensional integral imaging method, a new moiré‐free pixel design using a vertical lenticular sheet, and 2D/3D switching with liquid‐crystal gradient index (LC GRIN) lens are useful for 3D panels. Software technologies such as 2D3D image conversion, face tracking for 3D viewing zone shift, and 3D super‐resolution image processing are for enjoying 3D movies. We continue to invent a 3D new technology especially for mobile devices and for business use.

Multiple-hologram recording with one-beam encoding

This research proposes a method that uses a single object beam to record multiple images in a photorefractive crystal medium without having to use any reference wave. The object beam in this study is modulated using a lenticular lens array sheet to produce a set of sub-object beams. These beams are then angularly separated on the recording plane and their scattered waves overlapped in an iron-doped photorefractive LiNbO₃ crystal. This single-exposure, multiple-holographic-recording method is simple and proven successful via the experiments that recorded four holograms in a 30 x 1 mm³ LiNbO₃:Fe crystal with single exposure.

Autostereoscopic 3D projection display based on two lenticular sheets

We propose an autostereoscopic three-dimensional (3D) projection display. The display consists of four projectors, a projection screen, and two lenticular sheets. The operation principle and calculation equations are described in detail and the parallax images are corrected by means of homography. A 50-inch autostereoscopic 3D projection display prototype is developed. The normalized luminance distributions of viewing zones from the simulation and the measurement are given. Results agree well with the designed values. The proposed prototype presents full-resolution 3D images similar to the conventional prototype based on two parallax barriers. Moreover, the proposed prototype shows considerably higher brightness and efficiency of light utilization.

Cross-lenticular lens array for full parallax 3-D display with crosstalk reduction

As a 3-D display technology, stereoscopic imaging with lenticular lens sheet can only offer viewers the horizontal parallax. To reconstruct the 3-D image with parallax in both horizontal and vertical directions, the full parallax technique with micro-lens array was proposed. But due to the fabrication constraints and cost concerns of the micro-lens array, application of the full parallax technique is restricted in practice. In this paper we revisited the lenticular sheet method and cross-lenticular lens array formed by two lenticular sheets overlapped orthogonally. By analyzing the optical properties of this cross-lenticular lens array, we found that it has reasonable imaging qualities as a conventional micro-lens array. Besides, due to the poor optical property of the outskirt area of the cross-lenticular lens, the cross-lenticular lens array has better crosstalk suppression capability than the conventional one. Based on the analysis, in this paper, we used the proposed lens array to reconstruct a 3-D image and verified its practicability. The cross-lenticular lens array was found feasible to take the full parallax technique into commercial applications, with comparable advantages in terms of low-cost and easy fabrication over a large area.

Image Processing to Eliminate Crosstalk Between Neighboring View Images in Three-Dimensional Lenticular Display

In the multiview autostereoscopic 3D lenticular displays, the crosstalk between the neighboring view images at each view image's optimal viewing position influences the image quality and lowers the visual comfort of observers. A method is proposed to eliminate the crosstalk by correcting the intensity values of subpixels on synthetic images. We analyze the causes of crosstalk based on a synthetic image and deduce the equations of crosstalk elimination according to the relationship between the crosstalk coefficients of each view image observed through the lenticular sheet, the intensity values of subpixels displayed on the synthetic images, and the intensity values of subpixels observed through the lenticular sheet at the optimal viewing position. The experiment results verify the effectiveness of the proposed method. The method for crosstalk elimination is by means of image processing, and it does not change the parameters of the lenticular lens and the structure of the display screen.

一种减少柱面光栅自由立体显示图像串扰的方法

A method to reduce crosstalk in multi-view autostereoscopic three-dimensional (3D) displays based on the lenticular sheet is proposed. Correcting the luminance values of each parallax image displayed on the display screen is employed. We analyze the causes of crosstalk. We deduce the formulas of crosstalk reduction according to the relationship between crosstalk coefficients of each parallax image observed through the lenticular sheet, luminance values of each parallax image displayed on the display screen, and luminance values of each parallax image observed through the lenticular sheet at each viewing position. Experimental results verify the effectiveness of the proposed method.

Crosstalk reduction in multi-view autostereoscopic three-dimensional display based on lenticular sheet

Crosstalk reduction in multi-view autostereoscopic three-dimensional display based on lenticular sheet

Full-parallax three-dimensional display using new directional diffuser

A full-parallax three-dimensional (3D) display using a new directional diffuser is demonstrated. The display could present 3D images with 45 views comprising 9 horizontal views by 5 vertical views. The resolution and size of the 3D images displayed are 226?226 pixels and 300?300 (mm). The new directional diffuser consisting of two perpendicular lenticular sheets can be widely used in the display domain owing to its low cost and simple process.