Publicaties

A novel image approximation framework called steered mixture-of-experts (SMoE) was recently presented. SMoE has multiple applications in coding, scale-conversion, and general processing of image modalities. In particular, it has strong potential for coding and streaming higher dimensional image modalities that are necessary to leverage full translational and rotational freedom (6 degrees-of-freedom) in virtual reality for camera captured images. ...

The omnidirectional nature of Virtual Reality (VR) content provides an immersive experience for the viewer. At the same time, VR content relies heavily on the quality of the video to deliver an immersive experience. This study investigates the effect of video quality degradation on aspects of the viewer's quality of experience (QoE) via subjective (i.e., a questionnaire) and objective (i.e., electroencephalogram) methods. We measured the ...

Computational imaging and light field technology promise to deliver the required six-degrees-of-freedom for natural scenes in virtual reality. Already existing extensions of standardized video coding formats, such as multi-view coding and multi-view plus depth, are the most conventional light field video coding solutions at the moment. The latest multi-view coding format, which is a direct extension of the high efficiency video coding (HEVC) ...

Research in light field (LF) processing has heavily increased over the last decade. This is largely driven by the desire to achieve the same level of immersion and navigational freedom for camera-captured scenes as it is currently available for CGI content. Standardization organizations such as MPEG and JPEG continue to follow conventional coding paradigms in which viewpoints are discretely represented on 2-D regular grids. These grids are then ...

Watermarking enables the identification of digital pirates that illegally redistribute copyright-protected videos. One of the main challenges is for the watermark to be imperceptible, while not increasing the video bit rate. Additionally, the system should be robust to attacks that attempt to remove the watermark. Therefore, this paper proposes a robust watermarking technique that does not degrade the video quality nor negatively affect the ...

Subjective quality assessment is a necessary activity to validate objective measures or to assess the performance of innovative video processing technologies. However, designing and performing comprehensive tests requires expertise and a large effort especially for the execution part. In this work we propose a methodology that, given a set of processed video sequences prepared by video quality experts, attempts to reduce the number of subjective ...

Light field video is a promising technology for delivering the required six-degrees-of-freedom for natural content in virtual reality. Already existing multi-view coding (MVC) and multi-view plus depth (MVD) formats, such as MV-HEVC and 3D-HEVC, are the most conventional light field video coding solutions since they can compress video sequences captured simultaneously from multiple camera angles. 3D-HEVC treats a single view as a video sequence ...

Light field cameras (or plenoptic cameras) made it possible to not only capture information about the light intensity in a scene, but also the light direction traveling in space. The resulting light field images added two extra spatial dimensions to conventional 2D images by capturing a scene from different angles. Light field technology is expected to deliver the needed six-degrees-of-freedom in virtual reality, and it is a cornerstone ...

Video watermarking is a well-established technology to help identify digital pirates when they illegally re-distribute multimedia content. In order to provide every client with a unique, watermarked video, the traditional distribution architectures separately encode each watermarked video. However, since these encodings require a high amount of computational resources, such architectures do not scale well to a large number of users. Therefore, ...