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The article concerns the automatic calibration of a camera with radial distortion from a single image. It is known that, under the mild assumption of square pixels and zero skew, lines in the scene project into circles in the image, and three lines suffice to calibrate the camera up to an ambiguity between focal length and radial distortion. The calibration results highly depend on accurate circle...
In this paper, we present a novel approach to estimate the relative depth of regions in monocular images. There are several contributions. First, the task of monocular depth estimation is considered as a learning-to-rank problem which offers several advantages compared to regression approaches. Second, monocular depth clues of human perception are modeled in a systematic manner. Third, we show that...
Media playout buffer is widely employed by today's streaming media player to cope with short-term network variation and achieve continuous playout. However, the playout buffer inevitably introduces additional latency, affecting mobile live streaming experience. In this paper, we propose a novel adaptive playout buffer management approach to dynamically optimize the buffer latency while to a great...
This paper presents a computational framework for accurately estimating the disparity map of plenoptic images. The proposed framework is based on the variational principle and provides intrinsic sub-pixel precision. The light-field motion tensor introduced in the framework allows us to combine advanced robust data terms as well as provides explicit treatments for different color channels. A warping...
Eye gaze is an important non-verbal cue for human affect analysis. Recent gaze estimation work indicated that information from the full face region can benefit performance. Pushing this idea further, we propose an appearance-based method that, in contrast to a long-standing line of work in computer vision, only takes the full face image as input. Our method encodes the face image using a convolutional...
Crowd behaviour analysis is a challenging task in computer vision, mainly due to the high complexity of the interactions between groups and individuals. This task is particularly crucial given the magnitude of manual monitoring required for effective crowd management. Within this context, a key challenge is to conceive a highly generic, fine and context-independent characterisation of crowd behaviours...
We generalize Richardson-Lucy (RL) deblurring to 4-D light fields by replacing the convolution steps with light field rendering of motion blur. The method deals correctly with blur caused by 6-degree-of-freedom camera motion in complex 3-D scenes, without performing depth estimation. We introduce a novel regularization term that maintains parallax information in the light field while reducing noise...
The quantity and diversity of data in Light-Field videos makes this content valuable for many applications such as mixed and augmented reality or post-production in the movie industry. Some of such applications require a large parallax between the different views of the Light-Field, making the multi-view capture a better option than plenoptic cameras. In this paper we propose a dataset and a complete...
The last years have seen a quick rise of digital photography. Plenoptic cameras provide extended capabilities with respect to previous models. Multi-focus cameras enlarge the depth-of-field of the pictures using different focal lengths in the lens composing the array, but questions still arise on how to select and use these lenses. In this work a further insight on the lens selection was made, and...
Estimation of human energy expenditure in sports and exercise contributes to performance analyses and tracking of physical activity levels. The focus of this work is to develop a video-based method for estimation of energy expenditure in athletes. We propose a method using thermal video analysis to automatically extract the cyclic motion pattern, in walking and running represented as steps, and analyse...
Reproducible, robust robot control is particularly challenging at the microscale, where lesser understood surface forces, such as friction, dominate volumetric forces, such as magnetic attraction. In such an environment, an adaptive (or “uncalibrated”) controller which can dynamically adjust to changes in the operation environment is essential. This paper describes an uncalibrated controller utilizing...
We present a method for estimating the body orientation of seated people in a smart room by fusing low-resolution range information collected from downward pointed time-of-flight (ToF) sensors with synchronized speaker identification information from microphone recordings. The ToF sensors preserve the privacy of the occupants in that they only return the range to a small set of hit points. We propose...
A method of improving the location accuracy of a target when imaged from an unmanned aerial vehicle (UAV) is described. This method focuses on improving estimation of heading angle bias to then improve geolocation performance. A Particle Swarm Optimization (PSO) algorithm is employed to derive an expression of optimal flight path, which can be a guide for trajectory planning. The aircraft is commanded...
This paper presents a new depth estimation method for multiview systems with arbitrary camera locations. The method exploits the graph cuts method, where vertices of the graph represent segments used for controlling the trade-off between the quality of depth maps and the time of estimation, while preserving the original resolution of a depth map. Moreover, the inter-view consistency of the depth maps,...
The acquisition of partial BRDF measurements using light field cameras and several illumination directions raises critical questions regarding the accuracy of inferences based on that data. Therefore, we attempt to verify the quality of the reconstruction of a full BRDF using partial input data. A dataset that provides a densely sampled BRDF was used, both in viewing and illumination directions. We...
This paper points out a new telltale trace – the characteristic of perspective distortion (CPD), for the image forensics of faces. The perspective distortion is determined by the position of image shooting, and it is often overlooked when creating a forgery, which results in the inconsistency between the claimed camera parameters and the CPD in the face image. To investigate this consistency problem,...
In this paper, we introduce a new sensor system to measure the vehicle body velocity using a CMOS camera and it's motion blur. When the camera faced on the ground and mounted on the vehicle body is shaken by a specific path to artificially form a motion blur, a Modulated Motion Blur is recorded on the image sensor. This Modulated Motion Blur implies the relative motion between the camera and the ground...
This paper proposes a novel velocity estimation approach for single image points, while both the camera and the observed object may be in motion. In order to obtain absolute velocities, a flow-stereo setup is utilized, but no explicit depth reconstruction is carried out. Omitting the calculation in the Cartesian space increases the robustness of the estimation, which is shown in a comparison between...
This paper proposes a method for estimating the surface of transparent objects based on light field convergency. The light field convergency represents the degree of convergence of the light field at each point. The proposed method utilizes local photo consistency, which is one of characteristics of the light field convergency. Around a boundary contour, a point that is visible from viewpoints with...
Global motion estimation (GME) algorithms are typically employed on aerial videos captured by on-board UAV cameras to compensate for the artificial motion induced in these video frames due to camera motion. However, existing methods for GME have high computational complexity and are therefore not suitable for on-board processing in UAVs with limited computing capabilities. In this paper, we propose...
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