Abstract-This paper describes a cooperative testbed implementation of a new algorithm (Jin and Bertozzi, CDC 2007) for environmental boundary tracking and estimation using only localized noisy sensors. The tracking algorithm is based on Page's cumulative sum algorithm (CUSUM) a method for change-point detection. A geometric, biologically inspired, motion control algorithm allows individual vehicles to track and follow the environmental boundary without external positioning information. Relative positioning between vehicles allows several to maintain a convoy while tracking the boundary. The algorithm performs well in the presence of moderate sensor noise.

We present a numerical method for the simultaneous localization and parameter estimation of a fluorescent particle undergoing a discrete-time continuous-state Markov process. In particular, implementation of the method proposed in this work yields an approximation to the posterior density of the particle positions over time in addition to maximum likelihood estimates of fixed, unknown parameters. The method employs sequential Monte Carlo methods and can take into account complex, potentially nonlinear noise models, including shot noise and camera-specific readout noise, as well as a wide variety of motion models and observation models, including those representing recent engineered point spread functions. We demonstrate the technique by applying it to four scenarios, including a particle undergoing free, confined, and tethered diffusions.

The ability to track single fluorescent particles in three-dimensions with subdiffraction limit precision as well as sub-millisecond temporal resolution has enabled the understanding of many biophysical phenomena at the nanometer scale. While there are several techniques for achieving this, most require complicated experimental setups that are expensive to implement. These methods can offer superb performance but their complexity may be overwhelming to the end-user whose aim is only to understand the feature being imaged. In this work, we describe a method for tracking a single fluorescent particle using a standard confocal or multi-photon microscope configuration. It relies only on the assumption that the relative position of the measurement point and the particle can be actuated and that the point spread function has a global maximum that coincides with the particle's position. The method uses intensity feedback to calculate real-time position commands that "seek" the extremum of the point spread function as the particle moves through its environment. We demonstrate the method by tracking a diffusing quantum dot in a hydrogel on a standard epifluorescent confocal microscope.

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