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Visual simultaneous localization and mapping (V-SLAM) based tracking method for moving cameras has drawn increasing attention. The unpredictability of road conditions and noise from the camera calibration, however, make conventional ground plane estimation unreliable and adversely affecting the tracking result. In this paper, we propose an adaptive ground plane estimation algorithm in a moving monocular...
This paper presents an extension of block-based motion estimation for omnidirectional videos, based on a translational object motion model that accounts for the spherical geometry of the imaging system. We use this model to design a new algorithm to perform block matching in sequences of panoramic frames that are the result of the equirectangular projection. Experimental results demonstrate that significant...
Encoding spatio-temporally varying textures is challenging for standardised video encoders, with significantly more bits required for textured blocks compared to non-textured blocks. It is therefore beneficial to understand video textures in terms of both their spatio-temporal characteristics and their encoding statistics in order to optimize coding modes and performance. To this end, we examine the...
To obtain depth information from a stereo camera setup, a common way is to conduct disparity estimation between the two views; the disparity map thus generated may then also be used to synthesize arbitrary intermediate views. A straightforward approach to disparity estimation is block matching, which performs well with perspective data. When dealing with non-perspective imagery such as obtained from...
Recently, there has been an increased interest in capture, processing and rendering of visual content in form of point clouds. Among other challenges, subjective and objective quality assessments of point clouds are still open problems. Most proposed subjective quality evaluation methodologies are variants or extensions of counter parts from conventional approaches such as those proposed in various...
Omnidirectional images describe the color information at a given position from all directions. Affordable 360° cameras have recently been developed leading to an explosion of the 360° data shared on social networks. However, an omnidirectional image does not contain interesting content everywhere. Some part of the images are indeed more likely to be looked at by some users than others. Knowing these...
We propose a method of improving the quality of decoded HEVC motion fields attached to B-frames, in order to make them more suitable for video analysis and enhancement tasks. We use decoded HEVC motion vectors as a sparse set of motion "seeds", which guide an edge-preserving affine interpolation of coded motion (HEVC-EPIC) in order to obtain a much more physical representation of the scene...
Virtual reality (VR) applications target high-quality and zero-latency scene navigation to provide users with a full-immersion sensation within a scene. From a network perspective, this requires transmission of the omnidirectional content in its entirety, at a high resolution, which is not always feasible in bandwidth-limited networks. In this work, we propose an optimal transmission strategy for...
Omnidirectional imaging, also known as 360° and spherical imaging, records all 360° of a scene from a specific spatial position, thus offering the user the capability to enjoy three rotational degrees of freedom (3-DoF). To offer a good quality of experience, omnidirectional imaging requires very high bitrates as high spatial resolution are a must and, ideally, also high frame rates. Due to the lack...
A key factor to determine the quality of experience (QoE) of a video is its capability to convey the large spectrum of perceptual phenomena that our eyes can sense in real life. In order to meet this demand, the recent DVB UHD-1 Phase 2 specification employs new video features, such as higher spatial resolutions (4K/8K) and High Frame Rate (HFR). The first enables larger field of view and level of...
When displaying Standard Dynamic Range (SDR) video on High Dynamic Range (HDR) displays a reverse tone mapping operation can be employed to expand the dynamic range of the SDR video to that offered by the display. This paper presents a subjective performance evaluation of existing reverse Tone Mapping Operators (rTMOs). The presented study evaluates the performance of rTMOs acting on both well exposed...
In this paper we evaluate the effects of various data augmentation techniques on the automated classification of celiac disease using endoscopic imagery in the circumstances of limited training data. The used data augmentation techniques range from standard augmentation techniques like cropping patches and flipping to augmentation techniques using the full spectrum of affine or even projective transformations...
A novel sensory substitution algorithm based on the sonification of depth maps into physically based fluid flow sounds is described. Spatial properties are extracted from depth maps and mapped into parameters of an empirical phenomenological model of bubble statistics, which manages the generation of the corresponding synthetic fluid flow sound. Following minimal training, the proposed approach was...
Negative symptoms of schizophrenia significantly affect the daily functioning of patients, especially movement and expressive gestures. The diagnosis of such symptoms is often difficult and require the expertise of a trained clinician. Apart from these subjective methods, there is little research on developing objective methods to quantify the symptoms. Therefore, we explore body movement signals...
Characterized by geometry and photometry attributes, point cloud has become widely applied in the real-time presentation of various 3D objects and scenes. The development of even more precise capture devices and the increasing requirements for vivid rendering inevitably induce huge point capacity, thus making the point cloud compression a demanding issue. Considering the non-uniform sampling and time-variant...
First-person videos (FPVs) captured by wearable cameras have undesired shakiness because of fast changing views. When existing video stabilization techniques are applied, FPVs are transformed into cinematographic videos, losing the First-person motion information (FPMI) such as the recorder's interests and actions. We propose a system that can enhance viewability of FPVs by stabilizing them while...
Motion analysis and tracking often relies on multimodal signals, e.g., video, depth map, motion capture (MoCap), due to the completeness of information they jointly provide. The joint analysis of multimodal signals requires to know the correct timing, i.e., the signals to be aligned. In this paper we propose an approach to automatically estimate the correct matching and alignment between a video and...
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