Controversies and priorities in amyotrophic lateral sclerosis

Two decades after the discovery that 20% of familial amyotrophic lateral sclerosis (ALS) cases were linked to mutations in the superoxide dismutase-1 (SOD1) gene, a substantial proportion of the remainder of cases of familial ALS have now been traced to an expansion of the intronic hexanucleotide repeat sequence in C9orf72. This breakthrough provides an opportunity to re-evaluate longstanding concepts regarding the cause and natural history of ALS, coming soon after the pathological unification of ALS with frontotemporal dementia through a shared pathological signature of cytoplasmic inclusions of the ubiquitinated protein TDP-43. However, with profound clinical, prognostic, neuropathological, and now genetic heterogeneity, the concept of ALS as one disease appears increasingly untenable. This background calls for the development of a more sophisticated taxonomy, and an appreciation of ALS as the breakdown of a wider network rather than a discrete vulnerable population of specialised motor neurons. Identification of C9orf72 repeat expansions in patients without a family history of ALS challenges the traditional division between familial and sporadic disease. By contrast, the 90% of apparently sporadic cases and incomplete penetrance of several genes linked to familial cases suggest that at least some forms of ALS arise from the interplay of multiple genes, poorly understood developmental, environmental, and age-related factors, as well as stochastic events

Adaptive depth map estimation from 3D integral image

Integral Imaging (InIm) is one of the most promising technologies for producing full color 3-D images with full parallax. InIm requires only one recording in obtaining 3D information and therefore no calibration is necessary to acquire depth values. The compactness of using InIm in depth measurement has been attracting attention as a novel depth extraction technique. In this paper, an algorithm for depth extraction that builds on previous work by the authors is presented. Three main problems in depth map estimation from InIm have been solved; the uncertainty and region homogeneity at image location where errors commonly appear in disparity process, dissimilar displacements within the matching block around object borders, object segmentation. This method is based on the distribution of the sample variance in sub-dividing non-overlapping blocks. A descriptor which is unique and distinctive for each feature on InIm has been achieved. Comparing to state-of-the-art techniques, it is shown that the proposed algorithm has improvements on two aspects: depth map extraction level, computational complexity

Adaptive 3D-DCT based compression algorithms for integral images

This paper proposes a novel mean adaptive 3DDCT algorithm for 3D content to achieve the optimal result by trading of quality and compression of 3D image. The proposed method enables users to adjust the compression rate according to application areas by applying small blocks to the more detailing area (non -stationary regions) and larger blocks to the background or less details area (homogenous regions) [1]. This proposed method “Mean Adaptive 3D-DCT” is applied on Holoscopic 3D images also known as Integral Images. In addition, the experiment results prove the method is applicable to any 3D content

Reference based holoscopic 3D camera aperture stitching for widening the overall viewing angle

Holoscopic 3D imaging also known as Integral imaging is a promising technique for creating full color 3D optical models that exist in space independently of the viewer. The images exhibit continuous parallax throughout the viewing zone. In order to achieve depth control, robust and real-time, a single aperture holoscopic 3D imaging camera is used for recording holoscopic 3D image using a regularly spaced array of small lenslets, which view the scene at a slightly different angle to its neighbour. However, the main problem the holoscopic 3D camera aperture faces is that it is not big enough for recording larger scene with existing 2D camera sensors. This paper proposes a novel reference based holoscopic 3D camera aperture stitching method that enlarges overall viewing angle of the holoscopic 3D camera in post-production after the capture

Distributed pixel mapping for refining dark area in parallax barriers based holoscopic 3D Display

Autostereoscopic 3D Display is robustly developed and available in the market for both home and professional users. However 3D resolution with acceptable 3D image quality remains a great challenge. This paper proposes a novel pixel mapping method for refining dark areas between two pinholes by distributing it into 3 times smaller dark areas and creating micro-pinholes in parallax barriers based holoscopic 3D displays. The proposed method allows to project RED, GREEN, BLUE subpixels separately from 3 different pinholes and it distributes the dark spaces into 3 times smaller dark spaces, which become unnoticeable and improves quality of the constructed holoscopic 3D scene significantly. Parallax barrier technology refers to a pinhole sheet or device placed in front or back of a liquid crystal display, allowing to project viewpoint pixels into space that reconstructs a holoscopic 3D scene in space. The holoscopic technology mimics the imaging system of insects, such as the fly, utilizing a single camera, equipped with a large number of micro-lenses or pinholes, to capture a scene, offering rich parallax information and enhanced 3D feeling without the need of wearing specific eyewear

Scene depth extraction from Holoscopic Imaging technology

3D Holoscopic Imaging (3DHI) is a promising technique for viewing natural continuous parallax 3D objects within a wide viewing zone using the principle of “Fly's eye”. The 3D content is captured using a single aperture camera in real-time and represents a true volume spatial optical model of the object scene. The 3D content viewed by multiple viewers independently of their position, without 3D eyewear glasses. The 3DHI technique merely requires a single recording that the acquisition of the 3D information and the compactness of depth measurement that is used has been attracting attention as a novel depth extraction technique. This paper presents a new corresponding and matching technique based on a novel automatic Feature-Match Selection (FMS) algorithm. The aim of this algorithm is to estimate and extract an accurate full parallax 3D model form from a 3D Omni-directional Holoscopic Imaging (3DOHI) system. The basis for the novelty of the paper is on two contributions: feature blocks selection and corresponding automatic optimization process. There are solutions for three main problems related to the depth map estimation from 3DHI: uncertainty and region homogeneity at image location, dissimilar displacements within the matching block around object borders, and computational complexity

Omnidirectional Holoscopic 3D content generation using dual orthographic projection

In recent years there has been a considerable amount of development work been made in the area of Three-Dimensional (3D) imaging systems and displays. Such systems have attracted the attention and have been widely consumed by both home and professional users in sectors such as entertainment and medicine. However, computer generated 3D content remains a challenge as the 3D scene construction requires contributions from thousands of micro images “also known as elemental images”. Rendering microlens images is very time-consuming because each microlens image is rendered by a perspective or orthographic pinhole camera in a computer generated environment. In this paper we propose and present the development of a new method to simplify and speed-up the rendering process in computer graphics. We also describe omnidirectional 3D image recoding using a two-layer orthographic camera. Results show that it's rendering performance makes it an ideal candidate for real-time/interactive 3D content visualization application(s)

Pre-processing of holoscopic 3D image for autostereoscopic 3D displays

Holoscopic 3D imaging also known as Integral imaging is an attractive technique for creating full colour 3D optical models that exist in space independently of the viewer. The constructed 3D scene exhibits continuous parallax throughout the viewing zone. In order to achieve depth control, robust and real-time, a single aperture holoscopic 3D imaging camera is used for recording holoscopic 3D image using a regularly spaced array of microlens arrays, which view the scene at a slightly different angle to its neighbour. However, the main problem is that the microlens array introduces a dark borders in the recorded image and this causes errors at playback on the holoscopic 3D Display. This paper proposes a reference based pre-processing of holoscopic 3D image for autostereoscopic holoscopic 3D displays. The proposed method takes advantages of microlens as reference point to detect amount of introduced dark borders and reduce/remove them from the holoscopic 3D image

Generating stereoscopic 3D from holoscopic 3D

In this paper a single aperture motion picture camera based on holoscopic imaging used to generate high-resolution stereoscopic image. The idea of single aperture camera reduces the very cumbersome and expensive of dual cameras in stereoscopic production. The camera is known as light field camera, which was first proposed in 1908 by lippmann [1]. The rendering method relied on up-sampling, shift and integrating of different views to extract stereo images. This is the first experiment attempted to generate stereo form holoscopic content on motion capturing, where researchers so far have been experimenting on still images. In this paper presents motion picture image rendering on holoscopic content to generate content for stereoscopic systems. We have carried out experiments with focused plenoptic camera on a single stage omnidirectional integral camera arrangement with capturing both horizontal and vertical parallax, using a low cost lens array and relay lens. Our results show an improvement in the resolution of images with artefact free and also the rendered stereo content are played back on polarized stereoscopic system and anaglyph system to perceive the 3D depth using filter glasses in our experimental section