High frequency scanning response of an APD photocurrent for laser range finder

In this paper, the scanning response of the photocurrent emitted by a large area avalanche photodiode (APD) is studied for a 3D laser camera. This 3D camera is based on a phase-shift laser range-finder to measure distance from 1 to 20 m. To obtain a large field of view of the optical head, a large area APD working as an optoelectronic mixer is used. Photocurrent response versus light spot position above the APD active area is analysed for high frequency measurements. Optoelectronic mixing permits to measure the scanning response phase of the internal photoelectric current. Moreover, it is demonstrated that the signal phase depends on the photoelectric gain. Signal-to-noise ratio and distance measurement error for the 3D camera are then discussed.     

Landmark Matching via Large Deformation Diffeomorphisms on the Sphere

This paper presents a methodology and algorithm for generating diffeomorphisms of the sphere onto itself, given the displacements of a finite set of template landmarks. Deformation maps are constructed by integration of velocity fields that minimize a quadratic smoothness energy under the specified landmark constraints. We present additional formulations of this problem which incorporate a given error variance in the positions of the landmarks. Finally, some experimental results are presented. This work has application in brain mapping, where surface data is typically mapped to the sphere as a common coordinate system.     

Bayesian Robot Programming

We propose a new method to program robots based on Bayesian inference and learning. It is called BRP for Bayesian Robot Programming. The capacities of this programming method are demonstrated through a succession of increasingly complex experiments. Starting from the learning of simple reactive behaviors, we present instances of behavior combination, sensor fusion, hierarchical behavior composition, situation recognition and temporal sequencing. This series of experiments comprises the steps in the incremental development of a complex robot program. The advantages and drawbacks of BRP are discussed along with these different experiments and summed up as a conclusion. These different robotics programs may be seen as an illustration of probabilistic programming applicable whenever one must deal with problems based on uncertain or incomplete knowledge. The scope of possible applications is obviously much broader than robotics.     

Functional in-circuit characterisation of ΣΔ modulators

A method for the in-circuit functional testing of ΣΔ modulators is described which can be built in large integrated circuits or systems-on-chip. It allows for measuring gain and phase, as well as total harmonic distortion and signal to noise and harmonic distortion ratio parameters. This method can be built in-circuit using existing computational resources, such as digital signal processors or (re)configurable logic, which can therefore be used to implement both mission and test operations. Both simulation and experimental results were obtained which are in close agreement with those expected from the theory.