Monocular-based 3-D seafloor reconstruction and ortho-mosaicing by piecewise planar representation

Photo-mosaicing techniques have become popular for seafloor mapping in various marine science applications. However, the common methods cannot accurately map regions with high relief and topographical variations. Ortho-mosaicing borrowed from photogrammetry is an alternative technique that enables taking into account the 3-D shape of the terrain. A serious bottleneck is the volume of elevation information that needs to be estimated from the video data, fused, and processed for the generation of a composite ortho-photo that covers a relatively large seafloor area. We present a framework that combines the advantages of dense depth-map and 3-D feature estimation techniques based on visual motion cues. The main goal is to identify and reconstruct certain key terrain feature points that adequately represent the surface with minimal complexity in the form of piecewise planar patches. The proposed implementation utilizes local depth maps for feature selection, while tracking over several views enables 3-D reconstruction by bundle adjustment. Experimental results with synthetic and real data validate the effectiveness of the proposed approach

Calibration of a Structured Light-Based Stereo Catadioptric Sensor

Catadioptric sensors are combinations of mirrors and lenses made in order to obtain a wide field of view. In this paper we propose a new sensor that has omnidirectional viewing ability and it also provides depth information about the nearby surrounding. The sensor is based on a conventional camera coupled with a laser emitter and two hyperbolic mirrors. Mathematical formulation and precise specifications of the intrinsic and extrinsic parameters of the sensor are discussed. Our approach overcomes limitations of the existing omni-directional sensors and eventually leads to reduced costs of production

An approach to visual servoing based on coded light

Positioning a robot with respect to objects by using data provided by a camera is a well known technique called visual servoing. In order to perform a task, the object must exhibit visual features which can be extracted from different points of view. Then, visual servoing is object-dependent as it depends on the object appearance. Therefore, performing the positioning task is not possible in presence of non-textured objects or objects for which extracting visual features is too complex or too costly. This paper proposes a solution to tackle this limitation inherent to the current visual servoing techniques. Our proposal is based on the coded structured light approach as a reliable and fast way to solve the correspondence problem. In this case, a coded light pattern is projected providing robust visual features independently of the object appearance

Plane-to-plane positioning from image-based visual servoing and structured light

In this paper we face the problem of positioning a camera attached to the end-effector of a robotic manipulator so that it gets parallel to a planar object. Such problem has been treated for a long time in visual servoing. Our approach is based on linking to the camera several laser pointers so that its configuration is aimed to produce a suitable set of visual features. The aim of using structured light is not only for easing the image processing and to allow low-textured objects to be treated, but also for producing a control scheme with nice properties like decoupling, stability, well conditioning and good camera trajectory

A Vision of Students Today (2007)

Video produced by Martin Wesch with his students in their Digital Ethnography Class at Kansas State University. Looks at way in which students experience Higher Education. Further information can be found at http://mediatedcultures.net/ksudigg/ You may particularly want to look at a response "A Vision of Professors Today (by Sandra)" http://mediatedcultures.net/ksudigg/?p=125

Compilation of documents for the development of a state of art of the investigation of perdurability

A través del estudio y la investigación basados en bibliografía de diversas nacionalidades que data desde la década de los setenta hasta la actualidad, ha sido posible analizar la tendencia académica de las investigaciones acerca la Perdurabilidad. Esta recolección de estudios es una fuente de información para todos aquellos que deseen tener un entendimiento más profundo acerca de la teoría que sostiene el concepto de Perdurabilidad. A lo largo de esta investigación, el lector encontrará un conjunto de varios autores de distintas nacionalidades que abordaron el tema de la Perdurabilidad bajo alguna de sus concepciones (longevidad, resistencia, supervivencia); lo que permite tener una visión más amplia acerca de la importancia de ciertos estudios de acuerdo a su origen y contexto cultural. Es importante resaltar que esta investigación es netamente teórica con el propósito de aclarar el concepto de Perdurabilidad y facilitar futuras investigaciones acerca de este tema