scholarly journals Augmented reality using holographic display

2017 ◽  
Vol 3 (1) ◽  
Author(s):  
Hung-Chun Lin ◽  
Yung-Hsun Wu

AbstractAugmented reality (AR) provided extra information to the user by applying virtual image onto the real environment. There are many methods achieving AR. Holographic display is one of the potential ways due to its perfect 3D demonstration. Holographic display can provide the virtual 3D object with depth information. It can be realized an AR device with real 3D scene by combing holographic display. However, it is difficult to realize a compact holographic display with wide viewing angle and enough resolution. It limits holographic display to apply to AR. In this paper, we will discuss the requirements of holographic display based on the development of LCD, including resolution (ppi), viewing angle, image quality and backlight. We wish this article can provide preliminary direction for the LCD industry to develop AR technology using holographic display.

2021 ◽  
Vol 9 ◽  
Author(s):  
Yunpeng Liu ◽  
Xingpeng Yan ◽  
Xinlei Liu ◽  
Xi Wang ◽  
Tao Jing ◽  
...  

In this paper, an optical field coding method for the fusion of real and virtual scenes is proposed to implement an augmented reality (AR)-based holographic stereogram. The occlusion relationship between the real and virtual scenes is analyzed, and a fusion strategy based on instance segmentation and depth determination is proposed. A real three-dimensional (3D) scene sampling system is built, and the foreground contour of the sampled perspective image is extracted by the Mask R-CNN instance segmentation algorithm. The virtual 3D scene is rendered by a computer to obtain the virtual sampled images as well as their depth maps. According to the occlusion relation of the fusion scenes, the pseudo-depth map of the real scene is derived, and the fusion coding of 3D real and virtual scenes information is implemented by the depth information comparison. The optical experiment indicates that AR-based holographic stereogram fabricated by our coding method can reconstruct real and virtual fused 3D scenes with correct occlusion and depth cues on full parallax.


2020 ◽  
Vol 3 (1) ◽  
pp. 9-10
Author(s):  
Rehan Ahmed Khan

In the field of surgery, major changes that have occurred include the advent of minimally invasive surgery and the realization of the importance of the ‘systems’ in the surgical care of the patient (Pierorazio & Allaf, 2009). Challenges in surgical training are two-fold: (i) to train the surgical residents to manage a patient clinically (ii) to train them in operative skills (Singh & Darzi,2013). In Pakistan, another issue with surgical training is that we have the shortest duration of surgical training in general surgery of four years only, compared to six to eight years in Europe and America (Zafar & Rana, 2013). Along with it, the smaller number of patients to surgical residents’ ratio is also an issue in surgical training. This warrants formal training outside the operation room. It has been reported by many authors that changes are required in the current surgical training system due to the significant deficiencies in the graduating surgeon (Carlsen et al., 2014; Jarman et al., 2009; Parsons, Blencowe, Hollowood, & Grant, 2011). Considering surgical training, it is imperative that a surgeon is competent in clinical management and operative skills at the end of the surgical training. To achieve this outcome in this challenging scenario, a resident surgeon should be provided with the opportunities of training outside the operation theatre, before s/he can perform procedures on a real patient. The need for this training was felt more when the Institute of Medicine in the USA published a report, ‘To Err is Human’ (Stelfox, Palmisani, Scurlock, Orav, & Bates, 2006), with an aim to reduce medical errors. This is required for better training and objective assessment of the surgical residents. The options for this training include but are not limited to the use of mannequins, virtual patients, virtual simulators, virtual reality, augmented reality, and mixed reality. Simulation is a technique to substitute or add to real experiences with guided ones, often immersive in nature, that reproduce substantial aspects of the real world in a fully interactive way. Mannequins, virtual simulators are in use for a long time now. They are available in low fidelity to high fidelity mannequins and virtual simulators and help residents understand the surgical anatomy, operative site and practice their skills. Virtual patients can be discussed with students in a simple format of the text, pictures, and videos as case files available online, or in the form of customized software applications based on algorithms. In a study done by Courtielle et al, they reported that knowledge retention is increased in residents when it is delivered through virtual patients as compared to lecturing (Courteille et al., 2018).But learning the skills component requires hands-on practice. This gap can be bridged with virtual, augmented, or mixed reality. There are three types of virtual reality (VR) technologies: (i) non-immersive, (ii) semi-immersive, and (iii) fully immersive. Non-immersive (VR) involves the use of software and computers. In semi-immersive and immersive VR, the virtual image is presented through the head-mounted display(HMD), the difference being that in the fully immersive type, the virtual image is completely obscured from the actual world. Using handheld devices with haptic feedback the trainee can perform a procedure in the virtual environment (Douglas, Wilke, Gibson, Petricoin, & Liotta, 2017). Augmented reality (AR) can be divided into complete AR or mixed reality (MR). Through AR and MR, a trainee can see a virtual and a real-world image at the same time, making it easy for the supervisor to explain the steps of the surgery. Similar to VR, in AR and MR the user wears an HMD that shows both images. In AR, the virtual image is transparent whereas, in MR, it appears solid (Douglas et al., 2017). Virtual augmented and mixed reality has more potential to train surgeons as they provide fidelity very close to the real situation and require fewer physical resources and space compared to the simulators. But they are costlier, and affordability is an issue. To overcome this, low-cost solutions to virtual reality have been developed. It is high time that we also start thinking on the same lines and develop this means of training our surgeons at an affordable cost.


2015 ◽  
Vol 52 (6) ◽  
pp. 060901
Author(s):  
王迪 Wang Di ◽  
唐文华 Tang Wenhua ◽  
王君 Wang Jun ◽  
王琼华 Wang Qionghua

2019 ◽  
Vol 9 (10) ◽  
pp. 2118 ◽  
Author(s):  
Hao Zhang ◽  
Liangcai Cao ◽  
Guofan Jin

Holographic three-dimensional (3D) displays can reconstruct a whole wavefront of a 3D scene and provide rich depth information for the human eyes. Computer-generated holographic techniques offer an efficient way for reconstructing holograms without complicated interference recording systems. In this work, we present a technique for generating 3D computer-generated holograms (CGHs) with scalable samplings, by using layer-based diffraction calculations. The 3D scene is partitioned into multiple layers according to its depth image. Shifted Fresnel diffraction is used for calculating the wave diffractions from the partitioned layers to the CGH plane with adjustable sampling rates, while maintaining the depth information. The algorithm provides an effective method for scaling 3D CGHs without an optical zoom module in the holographic display system. Experiments have been performed, demonstrating that the proposed method can reconstruct quality 3D images at different scale factors.


Photonics ◽  
2021 ◽  
Vol 8 (8) ◽  
pp. 337
Author(s):  
Jiacheng Shi ◽  
Jianyu Hua ◽  
Fengbin Zhou ◽  
Min Yang ◽  
Wen Qiao

Glasses-free augmented reality (AR) 3D display has attracted great interest in its ability to merge virtual 3D objects with real scenes naturally, without the aid of any wearable devices. Here we propose an AR vector light field display based on a view combiner and an off-the-shelf purchased projector. The view combiner is sparsely covered with pixelated multilevel blazed gratings (MBG) for the projection of perspective virtual images. Multi-order diffraction of the MBG is designed to increase the viewing distance and vertical viewing angle. In a 20-inch prototype, multiple sets of 16 horizontal views form a smooth parallax. The viewing distance of the 3D scene is larger than 5 m. The vertical viewing angle is 15.6°. The light efficiencies of all views are larger than 53%. We demonstrate that the displayed virtual 3D scene retains natural motion parallax and high brightness while having a consistent occlusion effect with natural objects. This research can be extended to applications in areas such as human–computer interaction, entertainment, education, and medical care.


2019 ◽  
Vol 2019 (1) ◽  
pp. 237-242
Author(s):  
Siyuan Chen ◽  
Minchen Wei

Color appearance models have been extensively studied for characterizing and predicting the perceived color appearance of physical color stimuli under different viewing conditions. These stimuli are either surface colors reflecting illumination or self-luminous emitting radiations. With the rapid development of augmented reality (AR) and mixed reality (MR), it is critically important to understand how the color appearance of the objects that are produced by AR and MR are perceived, especially when these objects are overlaid on the real world. In this study, nine lighting conditions, with different correlated color temperature (CCT) levels and light levels, were created in a real-world environment. Under each lighting condition, human observers adjusted the color appearance of a virtual stimulus, which was overlaid on a real-world luminous environment, until it appeared the whitest. It was found that the CCT and light level of the real-world environment significantly affected the color appearance of the white stimulus, especially when the light level was high. Moreover, a lower degree of chromatic adaptation was found for viewing the virtual stimulus that was overlaid on the real world.


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