At the time of writing this paper, light field visualization has entered the professional environments in the industry and has also become commercially available. It is not yet present on the consu...

https://tandfonline.com/doi/pdf/10.1080/15980316.2019.1606120

The key performance indicators of projection-based light field visualization

At the time of this paper, research on the quality of light-field visualization is continuously gaining momentum, as the excellence in visual performance shall be one of the key enablers of the emergence and long-term presence of this technology on the consumer market. Experiments on perceived quality began in parallel with the appearance of commercially available light-field displays. As the techniques of subjective quality assessment on these displays are not standardized yet, certain parameters may greatly vary, such as viewing conditions. Although most of the current research efforts in this area address forms of static visualization, light-field video is also an essential target of quality evaluation. In this paper, we introduce the results of an experiment investigating the viewing conditions of light-field video quality assessment. The tests directly compare the perceived horizontal motion parallax of static viewing positions with motion patterns. The visual quality of the test conditions was degraded by the reduction of content spatial and angular resolution, as they both affect the smoothness of the horizontal motion parallax.

/pdf/the-viewing-conditions-of-light-field-video-for-subjective-c81p4trkya.pdf

The Viewing Conditions of Light-Field Video for Subjective Quality Assessment

The increasing availability of digital whole slide images opens new perspectives for computer-assisted image analysis complementing modern histopathology, assuming we can implement reliable and efficient image analysis algorithms to extract the biologically relevant information. Both validation and supervised learning techniques typically rely on ground truths manually made by human experts. However, this task is difficult, subjective and usually not exhaustive. This is a well-known issue in the field of biomedical imaging, and a common solution is the use of artificial “phantoms”. Following this trend, we study the feasibility of synthesizing artificial histological images to create perfect ground truths. In this paper, we show that it is possible to generate a synthetic whole slide image with reasonable computing resources, and we propose a way to evaluate its quality.

/pdf/synthesizing-whole-slide-images-2da095rhpr.pdf

Synthesizing whole slide images

Requirements are the basis upon which software architecture lies. As a consequence they should be expressed as precisely as possible in order to propose the best compromise between stakeholder needs and engineering constraints.While some measurements such as frame rate or latency are a widely known mean of expressing requirements in the 3D community, they often are loosely defined. This leads to software engineering decisions which exclude some of the most promising options.This paper proposes to adapt a non-functional requirements expression template used in general software architecture to the specific case of 3D based systems engineering. It shows that in the process some interesting proposals appear as a straightforward consequence of the better definition of the system to be built.

Requirement templates for distributed 3D graphics

There are several benefits of using a light field display over a traditional HMD; in particular the light field can avoid the vergence-accommodation conflict and can also correct for near- and farsightedness. By rendering only four corner cameras of a subimage array, then these four views can be interpolated in order to create all subimages of the light field. We implement the interpolation of the subimages in the light field with the use of pixel reprojection, while maintaining correct perspective and shading. We give an comprehensive explanation of the construction and calibration of a head mounted light field display, and finally we evaluate the image quality through image difference and conduct a user evaluation of the light field images in order to evaluate if users are able to perceive a difference in the light field images created with the full array of virtual cameras and our method using four cameras and pixel reprojection. In most cases the users were unable to distinguish the images, and we conclude that pixel reprojection is a feasible method for rendering light fields as far as quality is concerned.

Calibrating, rendering and evaluating the head mounted light field display

Light field displays have advantages over traditional stereoscopic head mounted displays, for example, because they can overcome the vergence-accommodation conflict. However, rendering light fields can be a heavy task for computers due to the number of images that have to be rendered. Since much of the information of the different images is redundant, we use pixel reprojection from the corner cameras to compute the remaining images in the light field. We compare the reprojected images with directly rendered images in a user test. In most cases, the users were unable to distinguish the images. In extreme cases, the reprojection approach is not capable of creating the light field. We conclude that pixel reprojection is a feasible method for rendering light fields as far as quality of perspective and diffuse shading is concerned, but render time needs to be reduced to make the method practical.

Light Field Rendering for Head Mounted Displays using Pixel Reprojection

While the concept of photorealism has important applications in computer graphics, the research community has not agreed on a definition of photorealism that specifies how to measure it. We employed two different test procedures, which correspond to different use scenarios, in order to determine the photorealism of a virtual reconstruction of a historic Viking building using two different lighting techniques. Even in this limited case, the measured degree of photorealism appears to depend on both the test procedure as well as the tested imagery; therefore, we conclude that there is no single measure of photorealism that is appropriate in all situations. Instead, photorealism appears to be a multifaceted phenomenon that requires different measurement procedures for different use scenarios. CR Categories: I.3.7 [Computer Graphics]: Three-Dimensional Graphics and Realism—Color, shading, shadowing, and texture; H.1.2 [Models and Principles]: User/Machine Systems—Human factors

/pdf/why-a-single-measure-of-photorealism-is-unrealistic-9scci4lhx1.pdf

Jákup Klein

Papers

Light Field Rendering for Head Mounted Displays using Pixel Reprojection

Why a Single Measure of Photorealism Is Unrealistic

Calibrating, rendering and evaluating the head mounted light field display