https://www.win.tue.nl/~atijssel/pdf_files/Bergant-Simpson-Tijsseling_2006.pdf

Water hammer with column separation: A historical review

We investigate the feasibility of reconstructing an arbitrarily-shaped specular scene (refractive or mirror-like) from one or more viewpoints. By reducing shape recovery to the problem of reconstructing individual 3D light paths that cross the image plane, we obtain three key results. First, we show how to compute the depth map of a specular scene from a single viewpoint, when the scene redirects incoming light just once. Second, for scenes where incoming light undergoes two refractions or reflections, we show that three viewpoints are sufficient to enable reconstruction in the general case. Third, we show that it is impossible to reconstruct individual light paths when light is redirected more than twice. Our analysis assumes that, for every point on the image plane, we know at least one 3D point on its light path. This leads to reconstruction algorithms that rely on an "environment matting" procedure to establish pixel-to-point correspondences along a light path. Preliminary results for a variety of scenes (mirror, glass, etc.) are also presented.

/pdf/a-theory-of-refractive-and-specular-3d-shape-by-light-path-30yvkxm9c5.pdf

A Theory of Refractive and Specular 3D Shape by Light-Path Triangulation

High dynamic range fringe acquisition: A novel 3-D scanning technique for high-reflective surfaces

Objects with mirroring optical characteristics are left out of the scope of most 3D scanning methods. We present here a new automatic acquisition approach, shape-from-distortion, that focuses on that category of objects, requires only a still camera and a color monitor, and produces range scans (plus a normal and a reflectance map) of the target. Our technique consists of two steps: first, an improved environment matte is captured for the mirroring object, using the interference of patterns with different frequencies to obtain sub-pixel accuracy. Then, the matte is converted into a normal and a depth map by exploiting the self-coherence of a surface when integrating the normal map along different paths. The results show very high accuracy, capturing even smallest surface details. The acquired depth maps can be further processed using standard techniques to produce a complete 3D mesh of the object.

/pdf/3d-acquisition-of-mirroring-objects-using-striped-patterns-2r5u1vwqya.pdf

3D Acquisition of mirroring objects using striped patterns

This paper presents a hierarchical classification of linear, distributed parameter models which have been used in the study of rigid, uniform fluid transmission lines. The development of the models from the fundamental equations of fluid dynamics is discussed, and the assumptions necessary in obtaining each model are shown. The solutions to the models are presented in general Laplace forms, and the terms that appear in the solutions are discussed with reference to the initial and subsequent assumptions. The existence of seven distinct forms of models was identified and verified by comparison with a vast number of apparently different models quoted in over three hundred research papers covering various engineering, medical, and biological applications. Significant contributions by various researchers over the last eighty years to the development of distributed parameter models of fluid transmission lines are reviewed. The application of the various models based upon comparisons made in the literature is de...

Fluid Transmission Lines—Distributed Parameter Models Part 1: A Review of the State of the Art:

We describe a new laser rangefinder for measurement of the shapes of specular objects. In many industrial contexts, objects with both Lambertian surfaces and specular surfaces are often manipulated. However, ordinary laser rangefinders usually cannot be used to measure specular objects. We propose a laser rangefinder for the measurement of specular objects based on a new idea in which the incident angle of a light-stripe upon the image sensor is limited through the use of a special light device. The concept of this rangefinder involves the application of triangulation to specular objects, which enables measurement of the shape of specular objects as well as Lambertian objects. We designed and built a prototype light-stripe projection rangefinder based on these principles. Experiments using the rangefinder successfully demonstrate the rangefinder's accuracy. The proposed rangefinder is a promising tool for the performance of many common industrial tasks including measurement of the shapes of polished metal and the inspection of soldered joint surfaces.

New laser rangefinder for three-dimensional shape measurement of specular objects

Knowledge acquisition method for conceptual design based on value engineering and axiomatic design theory

This paper applies our state construction method by ART neural network to robot navigation problems. Agents in this paper consist of ART neural network and contradiction resolution mechanism. The ART neural network serves as a mean of state recognition which maps stimulus inputs to a certain state and state construction which creates a new state when a current stimulus input cannot be categorized into any known states. On the other hand, the contradiction resolution mechanism (CRM) uses agents' state transition table to detect inconsistency among constructed states. In the proposed method, two kinds of inconsistency for the CRM are introduced: "Different results caused by the same states and the same actions" and "Contradiction due to ambiguous states." The simulation results on the robot navigation problems confirm the effectiveness of the proposed method.

/pdf/adaptive-state-construction-for-reinforcement-learning-and-5fw0zeqe4s.pdf

Adaptive state construction for reinforcement learning and its application to robot navigation problems

An Incremental State-Space Construction Based on the Notion of Contradiction for Reinforcement Learning

We discuss a coevolutionary genetic algorithm for constraint satisfaction. Our basic idea is to explore effective genetic information in the population, i.e., schemata, and to exploit the genetic information in order to guide the population to better solutions. Our coevolutionary genetic algorithm (CGA) consists of two GA populations; the first GA, called "H-GA", searches for the solutions in a given environment (problem), and the second GA, called "P-GA", searches for effective genetic information involved in the H-GA, namely, good schemata. Thus, each individual in P-GA consists of alleles in H-GA or "don't care" symbol representing a schema in the H-GA. These GA populations separately evolve in each genetic space at different abstraction levels and affect with each other by two genetic operators: "superposition" and "transcription". We then applied our CGA to constraint satisfaction problems (CSPs) incorporating a new stochastic "repair" operator for P-GA to raise the consistency of schemata with the (local) constraint conditions in CSPs. We carried out two experiments: First, we examined the performance of CGA on various "general" CSPs that are generated randomly for a wide variety of "density" and "tightness" of constraint conditions in the CSPs that are the basic measures of characterizing CSPs. Next, we examined "structured" CSPs involving latent "cluster" structures among the variables in the CSPs. For these experiments, computer simulations confirmed us the effectiveness of our CGA.

/pdf/coevolutionary-genetic-algorithm-for-constraint-satisfaction-35xmfctnjp.pdf

Tadataka Konishi

Papers

New laser rangefinder for three-dimensional shape measurement of specular objects

Knowledge acquisition method for conceptual design based on value engineering and axiomatic design theory

Adaptive state construction for reinforcement learning and its application to robot navigation problems

An Incremental State-Space Construction Based on the Notion of Contradiction for Reinforcement Learning

Coevolutionary genetic algorithm for constraint satisfaction with a genetic repair operator for effective schemata formation