3D Motion recovery via affine Epipolar geometry

Algorithms to perform point-based motion estimation under orthographic and scaled orthographic projection abound in the literature. A key limitation of many existing algorithms is that they operate on the minimum amount of data required, often requiring the selection of a suitable minimal set from the available data to serve as a local coordinate frame. Such approaches are extremely sensitive to errors and noise in the minimal set, and forfeit the advantages of using the full data set. Furthermore, attention is seldom paid to the statistical performance of the algorithms.We present a new framework that allowsall available features to be used in the motion computations, without the need to select a frame explicitly. This theory is derived in the context of theaffine camera, which preserves parallelism and generalises the orthographic, scaled orthographic and para-perspective models. We define the affine epipolar geometry for two such cameras, giving the fundamental matrix in this case. The noise resistant computation of the epipolar geometry is discussed, and a statistical noise model constructed so that confidence in the results can be assessed.The rigid motion parameters are then determineddirectly from the epipolar geometry, using the novel rotation representation of Koenderink and van Doorn (1991). The two-view partial motion solution comprises the scale factor between views, the projection of the 3D axis of rotation and the cyclotorsion angle, while the addition of a third view allows the true 3D rotation axis to be computed (up to a Necker reversal). The computed uncertainties in these parameters permit optimal estimates to be obtained over time by means of a linear Kalman filter. Our theory extends work by Huang and Lee (1989), Harris (1990), and Koenderink and van Doorn (1991), and results are given on both simulated and real data.     

Honey bees find the shortest path: a collective flow-mediated approach

Artificial Life and Robotics - Honey bees (Apis mellifera L.) are social insects that makes frequent use of volatile pheromone signals to collectively navigate unpredictable and unknown...     

Herding stochastic autonomous agents via local control rules and online target selection strategies

Autonomous Robots - We propose a simple yet effective set of local control rules to make a small group of “herder agents” collect and contain in a desired region a large ensemble of...     

Summarizing consumer reviews

Journal of Intelligent Information Systems - E-commerce giants like Amazon rely on consumer reviews to allow buyers to inform other potential buyers about a product’s pros and cons. While...     

Mid-IR real-time monitoring of the carbocationic polymerization of isobutylene and styrene

The in-situ monitoring of the living carbocationic polymerization of isobutylene (IB) and styrene (St) with a fiber optic Attenuated Total Reflection (ATR) probe in the mid-IR "fingerprint" range is reported here for the first time. Monomer consumption was followed by the disappearance of the C=C stretching for both IB and St, and the C−H bending of the CH₃-group in IB. The formation of polyisobutylene (PIB) was also monitored by tracing the asymmetrical doublet characteristic of C−H bending of the t-butyl groups of the PIB. Conversion measurements by conventional off-line gravimetry correlated well with the new technique. Received: 27 August 1997/Revised version: 2 November 1997/Accepted: 20 November 1997     

A disposable,integrated loop-mediated isothermal amplification cassette with thermally actuated valves

An inexpensive, disposable, integrated, polymer-based cassette for loop-mediated isothermal amplification (LAMP) of target nucleic acids was designed, fabricated, and tested. The LAMP chamber was equipped with single-use, thermally actuated valves made with a composite consisting of a mixture of PDMS and expandable microspheres. The effect of the composite composition on its expansion was investigated, and the valve’s performance was evaluated. In its closed state, the valve can hold pressures as high as 200 kPa without any significant leakage. Both the LAMP chamber and the valves were actuated with thin film heaters. The utility of the cassette was demonstrated by carrying out LAMP of Escherichia coli DNA target and reverse transcribed loop meditated isothermal amplification (RT-LAMP) of RNA targets. The amplicons were detected in real time with a portable, compact detector. The system was capable of detecting as few as 10 target molecules per sample in well under 1 h. The portable, integrated cassette system described here is particularly suited for applications at the point of care and in resource-poor countries, where funds and trained personnel are in short supply.     

Antimagic labeling and canonical decomposition of graphs

An antimagic labeling of a connected graph with m edges is an injective assignment of labels from {1,…,m} to the edges such that the sums of incident labels are distinct at distinct vertices. Hartsfield and Ringel conjectured that every connected graph other than K₂ has an antimagic labeling. We prove this for the classes of split graphs and graphs decomposable under the canonical decomposition introduced by Tyshkevich. As a consequence, we provide a sufficient condition on graph degree sequences to guarantee an antimagic labeling.