Natural 3D Images Research Articles

Three hundred sixty‐degree viewable linear grooves 3D display

AbstractWe proposed a linear grooves 3D display that can display 360° viewable 3D images by creating linear grooves that correspond to the viewpoint positions. In the conventional method, arc‐shaped grooves are drawn on a flat substrate of transparent film. However, depending on the viewing position, the image may be distorted. In addition, when a flat substrate is bent into a curved shape, the image is more affected than one observed in a flat shape. Furthermore, the conventional method of arc 3D display method cannot display a 3D image that corresponds to the viewpoint position. In this paper, we propose design and fabrication methods that reduce the image distortion for both flat and curved shapes. A 3D image displayed by the proposed method can change depending on the viewpoint position, and a natural 3D image with motion parallax can be observed. In the experiment, our proposed method fabricated a 360° 3D display by calculating the linear grooves and presented natural 3D images with smooth motion parallax.

3D light-field display with an increased viewing angle and optimized viewpoint distribution based on a ladder compound lenticular lens unit.

Three-dimensional (3D) light-field displays (LFDs) suffer from a narrow viewing angle, limited depth range, and low spatial information capacity, which limit their diversified application. Because the number of pixels used to construct 3D spatial information is limited, increasing the viewing angle reduces the viewpoint density, which degrades the 3D performance. A solution based on a holographic functional screen (HFS) and a ladder-compound lenticular lens unit (LC-LLU) is proposed to increase the viewing angle while optimizing the viewpoint utilization. The LC-LLU and HFS are used to create 160 non-uniformly distributed viewpoints with low crosstalk, which increases the viewpoint density in the middle viewing zone and provides clear monocular depth cues. The corresponding coding method is presented as well. The optimized compound lenticular lens array can balance between suppressing aberration and improving displayed quality. The simulations and experiments show that the proposed 3D LFD can present natural 3D images with the right perception and occlusion relationship within a 65° viewing angle.

360°tabletop floating integral imaging based on spatiotemporal perspective-oriented projecting

Traditional integral imaging (InIm) display fails to effectively support practical 360°tabletop three-dimensional (3D) display, although this method is commonly used as the ideal wall 3D display to exhibit realistic 3D image with correct geometric occlusion. The reason is that the distribution of the viewing zone is omnidirectional, and finite recovered 3D spatial information distributed in the viewing area right above the screen is fully wasted when the traditional InIm display is used as the tabletop display. To address this issue, a 360°tabletop floating InIm display with cylinder-typed viewing zone, instead of the omnidirectional viewing zone, is demonstrated with high utilization rate of the recovered 3D spatial information. A point light source array (PLSA) based integral imaging using the aberration-suppressed biconvex aspheric lens array (BALA) and the directional collimated backlight (DC-BL) is presented and configured to realize the perspective-oriented projecting with a large viewing angle. Meanwhile, the cylinder-typed viewing zone is formed by implementing perspective-oriented projecting with spatiotemporal multiplexing by the use of FGPA and rotating mechanism. Additionally, a novel spatial coding method for 3D light field reconstruction is proposed to guarantee the right spatial perception and occlusion effect with full smooth parallax property within the whole viewing zone. In the experiment, the proposed tabletop display prototype using a 12.5-inch high frame-rate LCD panel with the resolution of 1920 × 1080 presents natural tabletop 3D images with 79 × 79 viewpoints and clear floating focus depth of 18 cm in 360°cylinder-typed viewing zone.

Full-color computational holographic near-eye display

ABSTRACTNear-eye displays (NEDs) are an excellent candidate for the future of augmented reality. Conventional micro-display based NED designs mostly provide stereoscopic 3D experience, which leads to visual discomfort due to vergence-accommodation conflict. Computational holographic near-eye displays (HNEDs) can simultaneously provide wide FOV, retinal resolution, attractive form-factor, and natural depth cues including accommodation. In HNEDs, computer-generated holograms (CGHs) are displayed on a spatial light modulators (SLMs). We propose a CGH computation algorithm that applies to arbitrary paraxial optical architectures; where the SLM illumination beam can be collimated, converging or diverging, and the SLM image as seen by the eye box plane may form at an arbitrary location, and can be virtual or real. Our CGH computation procedure eliminates speckle noise, which is observed in all other laser-based displays, and chromatic aberrations resulting from the light sources and the optics. Our proof-of-concept experiments demonstrate that HNEDs with simple optical architectures can deliver natural 3D images within a wide FOV (70 degrees) at retinal resolution (30 cycles-per-degree), exceeding 4000 resolvable pixels on a line using a printed binary mask. With the advances in SLM technology, HNEDs can realize the ultimate personalized display, meeting the demand of emerging augmented and virtual reality applications.

Experimental verification of accommodation-convergence conflict in viewing integral photography

We experimentally verified the depth perception and accommodation-convergence conflict in viewing integral photography. For comparison, the same measurements were performed with binocular stereoscopic images and real objects. First, the depth perception in viewing an integral three-dimensional (3D) target was measured at three display resolutions: 153, 229, and 458 ppi. The results showed that the depth perception was dependent on the display resolution. The results were also evaluated in a statistical test at a significance level of 5%. The results showed that the recognized depth perception ranges were 180, 240, and 330 mm when the display resolutions were 153, 229, and 458 ppi, respectively. The results were also analyzed in terms of image resolution. This suggested that depth perception occurred at over 1.0 cpd. The accommodation and convergence responses in viewing an integral 3D target displayed on a 3D display with 458 ppi were measured using PowerRef 3. The experimental results were evaluated with a multiple comparison test. It was found that 6 of the 10 observers did not have an accommodation-convergence conflict when viewing the integral 3D target inside and outside the depth of field. In conclusion, integral photography can provide a natural 3D image that looks like a real object.

360-degree screen-free floating 3D image in a crystal ball using a spatially imaged iris and rotational multiview DFD technologies.

A rotational multiview depth-fused 3D (DFD) display and 360-deg displaying optics using a spatially imaged iris method are proposed to realize a 360-deg 3D image. This method enables displaying clear floating images in a crystal ball. Its symmetric optics provide clear and natural 360-deg images with smooth motion parallax in horizontal and vertical directions using the directional selectivity of a spatially imaged iris method and natural 3D images of a rotational multiview DFD display.

Measurement of static convergence and accommodation responses to images of integral photography and binocular stereoscopy.

Static convergence and accommodation responses were measured by comparing integral photography images, binocular stereoscopic images, and real objects in a measurement range from 450 to 900 mm. The experimental results were evaluated with a multiple comparison test. It was found that six of the ten observers did not have an accommodation-convergence conflict in viewing integral photography in the range. Moreover, the required resolution was found to be 0.7 or more and less than 1.4 cycles per degree for inducing accommodation. In conclusion, integral photography can provide a natural 3D image that looks like a real object.

Utilizing binocular vision to facilitate completely blind 3D image quality measurement

In the field of practical three-dimensional (3D) applications, blind measurement of the perceptual quality of distorted 3D images remains a challenging research topic. In this paper, we propose a completely blind 3D image quality measurement (IQM) metric that utilizes a binocular vision mechanism to better align with human perception. As its primary focus, this study is inspired by the visual processing in the primary visual cortex (V1) and the higher visual areas (V2) of binocular vision to facilitate blind 3D-IQM. Furthermore, the proposed metric does not require distorted samples or human subjective opinion scores for training. More specifically, the binocular quality-predictive features of areas V1 and V2 are first extracted from a corpus of pristine natural 3D images. Subsequently, a pristine multivariate Gaussian (MVG) model is trained from the extracted features. Finally, with the trained MVG model, the quality of distorted 3D images is measured using a Mahalanobis distance. Experimental results using two public benchmark 3D databases show that in comparison with current state-of-the-art IQM metrics, the proposed metric achieves excellent prediction performance.

Multi-Region Active Contours with a Single Level Set Function.

Segmenting an image into an arbitrary number of coherent regions is at the core of image understanding. Many formulations of the segmentation problem have been suggested over the past years. These formulations include, among others, axiomatic functionals, which are hard to implement and analyze, and graph-based alternatives, which impose a non-geometric metric on the problem. We propose a novel method for segmenting an image into an arbitrary number of regions using an axiomatic variational approach. The proposed method allows to incorporate various generic region appearance models, while avoiding metrication errors. In the suggested framework, the segmentation is performed by level set evolution. Yet, contrarily to most existing methods, here, multiple regions are represented by a single non-negative level set function. The level set function evolution is efficiently executed through the Voronoi Implicit Interface Method for multi-phase interface evolution. The proposed approach is shown to obtain accurate segmentation results for various natural 2D and 3D images, comparable to state-of-the-art image segmentation algorithms.

Rigorous analysis of an electric-field-driven liquid crystal lens for 3D displays

We numerically analyzed the optical performance of an electric field driven liquid crystal (ELC) lens adopted for 3-dimensional liquid crystal displays (3D-LCDs) through rigorous ray tracing. For the calculation, we first obtain the director distribution profile of the liquid crystals by using the Erickson-Leslie motional equation; then, we calculate the transmission of light through the ELC lens by using the extended Jones matrix method. The simulation was carried out for a 9view 3D-LCD with a diagonal of 17.1 inches, where the ELC lens was slanted to achieve natural stereoscopic images. The results show that each view exists separately according to the viewing position at an optimum viewing distance of 80 cm. In addition, our simulation results provide a quantitative explanation for the ghost or blurred images between views observed from a 3D-LCD with an ELC lens. The numerical simulations are also shown to be in good agreement with the experimental results. The present simulation method is expected to provide optimum design conditions for obtaining natural 3D images by rigorously analyzing the optical functionalities of an ELC lens.

Optimal projector configuration design for 300-Mpixel multi-projection 3D display

To achieve an immersive natural 3D experience on a large screen, a 300-Mpixel multi-projection 3D display that has a 100-inch screen and a 40° viewing angle has been developed. To increase the number of rays emanating from each pixel to 300 in the horizontal direction, three hundred projectors were used. The projector configuration is an important issue in generating a high-quality 3D image, the luminance characteristics were analyzed and the design was optimized to minimize the variation in the brightness of projected images. The rows of the projector arrays were repeatedly changed according to a predetermined row interval and the projectors were arranged in an equi-angular pitch toward the constant central point. As a result, we acquired very smooth motion parallax images without discontinuity. There is no limit of viewing distance, so natural 3D images can be viewed from 2 m to over 20 m.

P‐25: Viewing Zone Connection of Depth Fused 3D (DFD) Display

AbstractA DFD display consists of a stack of two transparent emitting screens. Though it can produce natural 3D images, its viewing zone has not been particularly wide to date. We expanded it by connecting viewing zones of DFD images.

Auto‐stereoscopic 60 view 3D using slanted lenticular lens arrays

A natural 3D image is considered by many people to be next‐step in evolution of displays. This paper introduces autostereoscopic 3D of 60‐view number, which is made using slanted lenticular lens array and LCD of 15.1 inch diagonal size and 3200 by 2400 pixel numbers and presents the results of our prototype. Due to its large view number, smooth motion parallax is observed and the visual fatigue is reduced.

20.1: Locally Switchable 3D Displays

3D displays will drastically enhance the viewing experience of future displays for many applications. Unfortunately, 3D displays generally have a lower resolution since the pixels are divided over more views. Therefore, some 3D displays have the opportunity to switch between 2D and 3D mode such that either natural 3D images or high-resolution 2D images can be displayed. However, especially for mobile applications it is advantageous to be able to display 3D and 2D at the same time. In this paper we will discuss the design and driving of locally switchable lenticulars, which combines perfect high-resolution 2D with natural 3D areas.

レリーフ調奥行きマップ生成方式

We propose a new 3D-input method using a relief-like depth map generation algorithm (REAL). REAL is based on the concept of reproducing a depth map, like the relief of a coin, from 3D input. Using REAL, a portable 3D-input system can be achieved using only a monocular camera and a photoflash. REAL is very simple and convenient compared with conventional technology that requires triangulation. In this paper, we describe an overview of the concept and the calculations of the depth map. We also report a subjective test of 3D images generated by REAL. The subjective test results indicated that observers perceive REAL images as natural 3D images.

Development of a Compact 3-D HDTV Camera with Zoom Lens

Research on shooting conditions of 3D program production for natural 3D images has been continued. In the study, it has been shown that orthostereoscopic conditions bring about no inconsistency between depth information from perspective of the lenses and that from binocular parallax. A newly developed 3D camera is based on orthostereoscopic conditions, which result in compactness of the camera (weight 8). At the same time, the new camera has a zooming function and is valuable in many ways, especially sport broadcasting. In this paper, we give an outline of the newly developed 3D HDTV camera and the results of subjective evaluation tests on psychological effects of the images shot by the camera. These tests show that the images shot by this camera are more powerful and comfortable to view than those shot by existing 3D cameras.

54.2: Natural Stereo Depth Creation Methodology for a Real‐time 2D‐to‐3D Image Conversion

AbstractWe propose a “Depth Creation by stereo Perception (DCP)” method that creates more natural and impressive 3D images than ever from input 2D images by their stereo perceptual information, which includes horizontal motion, color, contrast, sharpness, and composition. We also propose a “Linear Depth Control (LDC)” method that controls the binocular parallax of the created 3D images by their image depth position in order to improve the 3D effect of the converted images. And the real‐time 2D‐to‐3D image conversion unit implemented these new methods realizes more natural 3D images corresponding to various 3D displays from 2D images of any types and scenes.

無ひずみ条件に基づいた小形・軽量な立体ハイビジョンカメラの開発とその画面効果

Research on shooting conditions of 3D program production for natural 3D images has been continued. In the study, it has been shown that orthostereoscopic conditions bring about no inconsistency between depth information from perspective of the lenses and that from binocular parallax. A newly developed 3D camera is based on orthostereoscopic conditions which results in compactness of the camera (weight 8 kg). At the same time, the new camera has a zooming function and is valuable in many ways, especially sport broadcasting. In this paper, we give an outline of the newly developed 3D HDTV camera and the results of subjective evaluation tests on psychological effects of the images shot by the camera. These tests show that the images shot by this camera are more powerful and comfortable to view than those shot by existing 3D cameras.