[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

A scheme is developed for classifying the types of motion perceived by a humanlike robot. It is assumed that the robot receives visual images of the scene using a perspective system model. Equations, theorems, concepts, clues, etc., relating the objects, their positions, and their motion to their images on the focal plane are presented. >

http://ieeexplore.ieee.org/iel2/815/3148/00100651.pdf

Robot vision

/pdf/remote-sensing-of-the-environment-4yfxjaaswe.pdf

Remote sensing of the environment

This paper provides a comprehensive review of the domain of physical layer security in multiuser wireless networks. The essential premise of physical layer security is to enable the exchange of confidential messages over a wireless medium in the presence of unauthorized eavesdroppers, without relying on higher-layer encryption. This can be achieved primarily in two ways: without the need for a secret key by intelligently designing transmit coding strategies, or by exploiting the wireless communication medium to develop secret keys over public channels. The survey begins with an overview of the foundations dating back to the pioneering work of Shannon and Wyner on information-theoretic security. We then describe the evolution of secure transmission strategies from point-to-point channels to multiple-antenna systems, followed by generalizations to multiuser broadcast, multiple-access, interference, and relay networks. Secret-key generation and establishment protocols based on physical layer mechanisms are subsequently covered. Approaches for secrecy based on channel coding design are then examined, along with a description of inter-disciplinary approaches based on game theory and stochastic geometry. The associated problem of physical layer message authentication is also briefly introduced. The survey concludes with observations on potential research directions in this area.

/pdf/principles-of-physical-layer-security-in-multiuser-wireless-3w4jvwpgy4.pdf

Principles of Physical Layer Security in Multiuser Wireless Networks: A Survey

In this paper, we propose a unified framework to generate a pleasant and high-quality street-view panorama by stitching multiple panoramic images captured from the cameras mounted on the mobile platform. Our proposed framework is comprised of four major steps: image warping, color correction, optimal seam line detection and image blending. Since the input images are captured without a precisely common projection center from the scenes with the depth differences with respect to the cameras to different extents, such images cannot be precisely aligned in geometry. Therefore, an efficient image warping method based on the dense optical flow field is proposed to greatly suppress the influence of large geometric misalignment at first. Then, to lessen the influence of photometric inconsistencies caused by the illumination variations and different exposure settings, we propose an efficient color correction algorithm via matching extreme points of histograms to greatly decrease color differences between warped images. After that, the optimal seam lines between adjacent input images are detected via the graph cut energy minimization framework. At last, the Laplacian pyramid blending algorithm is applied to further eliminate the stitching artifacts along the optimal seam lines. Experimental results on a large set of challenging street-view panoramic images captured form the real world illustrate that the proposed system is capable of creating high-quality panoramas.

A Unified Framework for Street-View Panorama Stitching.

Because the colours in an image convey a lot of information, almost all image database systems support colour content queries. Unfortunately colour based queries do not always return the images that were sought even although there is a good colour match. Such failures are easily explained. We as human observers do not see raw image colours but rather make an interpretation of the colours in an image. Our interpretation allows us to decouple the intrinsic colour of the objects and surfaces, captured in an image, from the colour of the illumination. An indoor picture with a yellowish colour cast is interpreted as just that, we do not think that all the objects in the scene are more yellow than they usually are. In contrast, image database systems generally make no such comparable interpretation.

In this paper we set forth an experimental study that attempts to quantify the nature and magnitude of the illumination colour problem. We are interested in measuring how image colours depend on illumination and how this dependency might be removed. Our work based on a small, but accurately calibrated, image database comprising 11 colourful objects imaged under 4 typical household lights. Because illumination colour impacts so dramatically on image colours, querying this dataset by colour-content delivers very poor indexing. To improve indexing performance, the illumination bias in images needs to be removed. This is done by applying an appropriate mapping to the image colours (e.g. a reddish cast can be removed by reducing the redness at each pixel). We found that mapping image colours based on a measure of the illuminant results in good indexing. However, when the mapping depends on both scene content and illumination together, the indexing performance is even better still. This is a surprising result since it is accepted doctrine that a change in illuminants should result in a systematic change in image colours and this change should effect all images equally (scene content should not add any useful information). Of course if illumination colour depends on scene content then it will be difficult to measure since the spectral statistics of the scene are also unknown. If measurement is difficult, estimation (using a colour constancy algorithm) must be more difficult still.

/pdf/colour-indexing-across-illumination-1iymj2qoqb.pdf

Colour indexing across illumination

Railway Tunnel SubSurface Inspection (RTSSI) is essential for targeted structural maintenance. ‘Effective’ detection, localisation and characterisation of fully concealed features (i.e., assets, defects) is the primary challenge faced by RTSSI engineers, particularly in historic masonry tunnels. Clear conveyance and communication of gathered information to end-users poses the less frequently considered secondary challenge. The purpose of this review is to establish the current state of the art in RTSSI data acquisition and information conveyance schemes, in turn formalising exactly what constitutes an ‘effective’ RTSSI visualisation framework. From this knowledge gaps, trends in leading RTSSI research and opportunities for future development are explored. Literary analysis of over 300 resources (identified using the 360-degree search method) informs data acquisition system operation principles, common strengths and limitations, alongside leading studies and commercial tools. Similar rigor is adopted to appraise leading information conveyance schemes. This provides a comprehensive whilst critical review of present research and future development opportunities within the field. This review highlights common shortcomings shared by multiple methods for RTSSI, which are used to formulate robust criteria for a contextually ‘effective’ visualisation framework. Although no current process is deemed fully effective; a feasible hybridised framework capable of meeting all stipulated criteria is proposed based on identified future research avenues. Scope for novel analysis of helical point cloud subsurface datasets obtained by a new rotating ground penetrating radar antenna is of notable interest.

/pdf/developments-in-3d-visualisation-of-the-rail-tunnel-1kujeh3m.pdf

Developments in 3D Visualisation of the Rail Tunnel Subsurface for Inspection and Monitoring

Defect edge reconstruction based on region growing using the Hausdorff distance

RFID sensor system for detecting corrosion progression using transient responses

The use of a multi-layer structure is widely recognized in aerospace engineering due to the fact that structural and functional properties can be implemented by designing geometric structure. Eddy current pulsed thermography (ECPT) is one of the crucial NDT techniques to inspect and evaluate the defects in composite multi-layer structure due to the volumetric heating nature. Thus, it is important to investigate the scattering electromagnetic wave into the interface of multi-layer structure to improve the detectability and evaluation capbility of an ECPT system. In this work, the conductivity tensor form is used to describe the scattering EM wave in the 3D FEM model to investigate the fiber orientation influence on each layer interface. The semi-analytical model is used to prove the concept and both results are validated by experimental studies with dedicated samples. The findings can be applied for simulating the scattering electromagnetic behavior in the interface of the multi-layer structure.

Gui Yun Tian

Papers

Colour indexing across illumination

Developments in 3D Visualisation of the Rail Tunnel Subsurface for Inspection and Monitoring

Defect edge reconstruction based on region growing using the Hausdorff distance

RFID sensor system for detecting corrosion progression using transient responses

Investigation of layer interface model of multi-layer structure using semi-analytical and FEM analysis for eddy current pulsed thermography