Compression of Vector Field Changing in Time

One of the problems connected with a real-time protein-ligand docking simulation is the need to store series of precomputed electrostatic force fields of a molecule changing in time. A single frame of the force field is a 3D array of floating point vectors and it constitutes approximately 180 MB of data. Therefore requirements on storage grow rapidly if several hundreds of such frames need to be stored. We propose a lossy compression method of such force field, based on audio and video coding, and we evaluate its properties and performance

Challenges and Opportunities for Designing Tactile Codecs from Audio Codecs

Haptic communications allows physical interaction over long distances and greatly complements conventional means of communications, such as audio and video. However, whilst standardized codecs for video and audio are well established, there is a lack of standardized codecs for haptics. This causes vendor lock-in and thereby greatly limits scalability, increases cost and prevents advanced usage scenarios with multi-sensors/actuators and multi-users. The aim of this paper is to introduce a new approach for understanding and encoding tactile signals, i.e. the sense of touch, among haptic interactions. Inspired by various audio codecs, we develop a similar methodology for tactile codecs. Notably, we demonstrate that tactile and audio signals are similar in both time and frequency domains, thereby allowing audio coding techniques to be adapted to tactile codecs with appropriate adjustments. We also present the differences between audio and tactile signals that should be considered in future designs. Moreover, in order to evaluate the performance of a tactile codec, we propose a potential direction of designing an objective quality metric which complements haptic mean opinion scores (h-MOS). This, we hope, will open the door for designing and assessing tactile codecs

Metamaterial bricks and quantization of meta-surfaces

Controlling acoustic fields is crucial in diverse applications such as loudspeaker design, ultrasound imaging and therapy or acoustic particle manipulation. The current approaches use fixed lenses or expensive phased arrays. Here, using a process of analogue-to-digital conversion and wavelet decomposition, we develop the notion of quantal meta-surfaces. The quanta here are small, pre-manufactured three-dimensional units—which we call metamaterial bricks—each encoding a specific phase delay. These bricks can be assembled into meta-surfaces to generate any diffraction-limited acoustic field. We apply this methodology to show experimental examples of acoustic focusing, steering and, after stacking single meta-surfaces into layers, the more complex field of an acoustic tractor beam. We demonstrate experimentally single-sided air-borne acoustic levitation using meta-layers at various bit-rates: from a 4-bit uniform to 3-bit non-uniform quantization in phase. This powerful methodology dramatically simplifies the design of acoustic devices and provides a key-step towards realizing spatial sound modulators

Far touch: integrating visual and haptic perceptual processing on wearables

The evolution of electronic computers seems to have now reached the ubiquitous realm of wearable computing. Although a vast gamut of systems has been proposed so far, we believe most systems lack proper feedback for the user. In this dissertation, we not only contribute to solving the feedback problem, but we also consider the design of a system to acquire and reproduce the sense of touch. In order for such a system to be feasible, a few important problems need to be considered. Here, we address two of them. First, we know that wireless streaming of high resolution video to a head-mounted display requires high compression ratio. Second, we know that the choice of a proper feedback for the user depends on his/her ability to perceive it confidently across different scenarios. In order to solve the first problem, we propose a new limit that promises theoretically achievable data reduction ratios up to approximately 9:1 with no perceptual loss in typical scenarios. Also, we introduce a novel Gaussian foveation scheme that provides experimentally achievable gains up to approximately 2 times the compression ratio of typical compression schemes with less perceptual loss than in typical transmissions. The background material of both the limit and the foveation scheme includes a proposed pointwise retina-based constraint called pixel efficiency, that can be globally processed to reveal the perceptual efficiency of a display, and can be used together with a lossy parameter to locally control the spatial resolution of a foveated image. In order to solve the second problem, we provide an estimation of difference threshold that suggests that typically humans are able to discriminate between at least 6 different frequencies of an electrotactile stimulation. Also, we propose a novel sequence of experiments that suggests that a change from active touch to passive touch, or from a visual-haptic environment to a haptic environment, typically yields a reduction of the sensitivity index d' and in an increase of the response bias c

Haptic data reduction through dynamic perceptual analysis and event-based communication

This research presents an adjustable and flexible framework for haptic data compression and communication that can be used in a robotic teleoperation session. The framework contains a customized event-driven transmission control protocol, several dynamically adaptive perceptual and prediction methods for haptic sample reduction, and last but not the least, an architecture for the data flow

Visual Content Characterization Based on Encoding Rate-Distortion Analysis

Visual content characterization is a fundamentally important but under exploited step in dataset construction, which is essential in solving many image processing and computer vision problems. In the era of machine learning, this has become ever more important, because with the explosion of image and video content nowadays, scrutinizing all potential content is impossible and source content selection has become increasingly difficult. In particular, in the area of image/video coding and quality assessment, it is highly desirable to characterize/select source content and subsequently construct image/video datasets that demonstrate strong representativeness and diversity of the visual world, such that the visual coding and quality assessment methods developed from and validated using such datasets exhibit strong generalizability. Encoding Rate-Distortion (RD) analysis is essential for many multimedia applications. Examples of applications that explicitly use RD analysis include image encoder RD optimization, video quality assessment (VQA), and Quality of Experience (QoE) optimization of streaming videos etc. However, encoding RD analysis has not been well investigated in the context of visual content characterization. This thesis focuses on applying encoding RD analysis as a visual source content characterization method with image/video coding and quality assessment applications in mind. We first conduct a video quality subjective evaluation experiment for state-of-the-art video encoder performance analysis and comparison, where our observations reveal severe problems that motivate the needs of better source content characterization and selection methods. Then the effectiveness of RD analysis in visual source content characterization is demonstrated through a proposed quality control mechanism for video coding by eigen analysis in the space of General Quality Parameter (GQP) functions. Finally, by combining encoding RD analysis with submodular set function optimization, we propose a novel method for automating the process of representative source content selection, which helps boost the RD performance of visual encoders trained with the selected visual contents

Técnicas de compresión de imágenes hiperespectrales sobre hardware reconfigurable

Tesis de la Universidad Complutense de Madrid, Facultad de Informática, leída el 18-12-2020Sensors are nowadays in all aspects of human life. When possible, sensors are used remotely. This is less intrusive, avoids interferces in the measuring process, and more convenient for the scientist. One of the most recurrent concerns in the last decades has been sustainability of the planet, and how the changes it is facing can be monitored. Remote sensing of the earth has seen an explosion in activity, with satellites now being launched on a weekly basis to perform remote analysis of the earth, and planes surveying vast areas for closer analysis...Los sensores aparecen hoy en día en todos los aspectos de nuestra vida. Cuando es posible, de manera remota. Esto es menos intrusivo, evita interferencias en el proceso de medida, y además facilita el trabajo científico. Una de las preocupaciones recurrentes en las últimas décadas ha sido la sotenibilidad del planeta, y cómo menitoirzar los cambios a los que se enfrenta. Los estudios remotos de la tierra han visto un gran crecimiento, con satélites lanzados semanalmente para analizar la superficie, y aviones sobrevolando grades áreas para análisis más precisos...Fac. de InformáticaTRUEunpu

The Reality of Virtual Environments: WPE II Paper

Recent advances in computer technology have made it now possible to create and display three-dimensional virtual environments for real-time exploration and interaction by a user. This paper surveys some of the research done in this field at such places as: NASA\u27s Ames Research Center, MIT\u27s Media Laboratory, The University of North Carolina at Chapel Hill, and the University of New Brunswick. Limitations to the reality of these simulations will be examined, focusing on input and output devices, computational complexity, as well as tactile and visual feedback