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

Light emitting diodes reliability review

We present an algorithm of color image understanding which segments the image after analyzing sur-faces with color variations due to lighting condition and object colors. The work is based on dichromaticreflection model according to the strategy of hypothesis plus test, following the continuity of image and thefeature of color clusters, the algorithm completes the image segmentation and gives forth a physical des-cription of imaging process, including intrinsic images, segmented image, the color of light and objects. Re-flecting respectively the propertics of light condition and every objects, both matte image and highlight im-age compose the intrinsic images.

A physical approach to color image understanding

Short-term accelerated life test activity on high brightness light emitting diodes is reported. Two families of 1-W light-emitting diodes (LEDs) from different manufacturers were submitted to distinct stress conditions: high temperature storage without bias and high dc current test. During aging, degradation mechanisms like light output decay and electrical property worsening were detected. In particular, the degradation in light efficiency induced by thermal storage was found to follow an exponential law, and the activation energy of the process was extrapolated. Aged devices exhibited a modification of the package epoxy color from white to brown. The instability of the package contributes to the overall degradation in terms of optical and spectral properties. In addition, an increase in thermal resistance was detected on one family of LEDs. This increase induces higher junction temperature levels during operative conditions. In order to correlate the degradation mechanisms and kinetics found during thermal stress, a high dc current stress was performed. Results from this comparative analysis showed similar behavior, implying that the degradation process of dc current aged devices is thermal activated due to high temperatures reached by the junction during stress. Finally, the different effects of the stress on two families of LEDs were taken into account in order to identify the impact of aging on device structure.

Accelerated Life Test of High Brightness Light Emitting Diodes

Machine Learning for Cultural Heritage: A Survey

We present a review of recent techniques for performing geometric analysis in cultural heritage CH applications. The survey is aimed at researchers in the areas of computer graphics, computer vision and CH computing, as well as to scholars and practitioners in the CH field. The problems considered include shape perception enhancement, restoration and preservation support, monitoring over time, object interpretation and collection analysis. All of these problems typically rely on an understanding of the structure of the shapes in question at both a local and global level. In this survey, we discuss the different problem forms and review the main solution methods, aided by classification criteria based on the geometric scale at which the analysis is performed and the cardinality of the relationships among object parts exploited during the analysis. We finalize the report by discussing open problems and future perspectives.

/pdf/a-survey-of-geometric-analysis-in-cultural-heritage-30n5cg5e41.pdf

A Survey of Geometric Analysis in Cultural Heritage

We propose a simple yet efficient steganalytic algorithm for watermarks embedded by two state-of-the-art 3D watermarking algorithms by Cho et al. The main observation is that while in a clean model the means/variances of Cho et al.’s normalized histogram bins are expected to follow a Gaussian distribution, in a marked model their distribution will be bimodal. The proposed algorithm estimates the number of bins through an exhaustive search and then the presence of a watermark is decided by a tailor made normality test or a $t$ -test. We also propose a modification of Cho et al.’s watermarking algorithms with the watermark embedded by changing the histogram of the radial coordinates of the vertices. Rather than targeting a continuous statistics such as the mean or variance of the values in a bin, the proposed watermarking modifies a discrete statistic, which here is the height of the histogram bin, to achieve watermark embedding. Experimental results demonstrate that the modified algorithm offers not only better resistance against the steganalytic attack we developed, but also an improved robustness/capacity trade-off.

/pdf/a-3d-steganalytic-algorithm-and-steganalysis-resistant-336ri5q9oa.pdf

A 3D Steganalytic Algorithm and Steganalysis-Resistant Watermarking

High brightness GaN LEDs degradation during dc and pulsed stress

Nowadays, 3D acquisition devices allow us to capture the geometry of huge Cultural Heritage (CH) sites, historical buildings and urban environments We present a scalable real-time method to render this kind of models without requiring lengthy preprocessing The method does not make any assumptions about sampling density or availability of normal vectors for the points On a frame-by-frame basis, our GPU accelerated renderer computes point cloud visibility, fills and filters the sparse depth map to generate a continuous surface representation of the point cloud, and provides a screen-space shading term to effectively convey shape features The technique is applicable to all rendering pipelines capable of projecting points to the frame buffer To deal with extremely massive models, we integrate it within a multi-resolution out-of-core real-time rendering framework with small pre-computation times Its effectiveness is demonstrated on a series of massive unstructured real-world Cultural Heritage datasets The small precomputation times and the low memory requirements make the method suitable for quick onsite visualizations during scan campaigns

/pdf/real-time-rendering-of-massive-unstructured-raw-point-clouds-xchezsacdz.pdf

Real-time rendering of massive unstructured raw point clouds using screen-space operators

We propose to exploit the color capabilities of recent rapid prototyping hardware devices to enhance the visual appearance of reproduced objects. In particular, by carefully pre-computing surface shading, we are able to counterbalance the sub-surface scattering (SSS) effects that hinder the perception of fine surface details. As a practical result, we are able to reproduce small scale copies of cultural heritage artifacts with an increased readability of the tiniest features and particulars, without requiring manual post-reproduction interventions or hand painting.

/pdf/color-enhancement-for-rapid-prototyping-2pvmv59jxs.pdf

Ruggero Pintus

Papers

A Survey of Geometric Analysis in Cultural Heritage

A 3D Steganalytic Algorithm and Steganalysis-Resistant Watermarking

High brightness GaN LEDs degradation during dc and pulsed stress

Real-time rendering of massive unstructured raw point clouds using screen-space operators

Color enhancement for rapid prototyping