changed colors of boxkde and weighted average
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@@ -1,7 +1,7 @@
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\section{Particle Filtering}
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As described earlier, we use a CONDENSATION particle filter to implement the recursive state estimator described in section \ref{sec:rse}.
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A set of particles is defined by $\{\vec{X}^i_{t}, w^i_{t} \}_{i=1}^N$, where $\mParticleVec^{i}_{t}$ is sampled based on the state transition $p(\mStateVec_{t} \mid \mStateVec_{t-1}, \mObsVec_{t-1})$.
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A set of $N$ particles is defined by $\{\vec{X}^i_{t}, w^i_{t} \}_{i=1}^N$, where $\mParticleVec^{i}_{t}$ is sampled based on the state transition $p(\mStateVec_{t} \mid \mStateVec_{t-1}, \mObsVec_{t-1})$.
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The weight $w_t^i$ is obtained by the probability density of the state evaluation $p(\mObsVec_{t} \mid \mStateVec_{t})$.
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A particle set approximates the posterior as follows:
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@@ -103,10 +103,11 @@ Finally, we have all necessary tools to implement the second method to prevent i
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For this, the state transition model is extended.
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Compared to the resampling step, as used by the first method, the transition $p(\mStateVec_{t} \mid \mStateVec_{t-1}, \mObsVec_{t-1})$ enables us to use prior measurements, which is obviously necessary for all \docWIFI{} related calculations.
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As described in chapter \ref{sec:transition}, our transition method only allows to sample particles at positions, that are actual feasible for a humans within a building e.g. no walking trough walls.
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If a particle targets a position which is not walk-able e.g. behind a wall, we draw a new position within a very small, but reachable area around its current position.
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If a particle targets a position which is not walk-able e.g. behind a wall, we deploy a strategy how to handle this.
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For example, drawing a new position within a very small, but reachable area around the particle's current position.
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%
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%Instead of such a small area or even the complete building, as suggested in method one, we now define a sphere.
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To prevent sample impoverishment we extend this transition method by making the reachable area depended upon $D_\text{KL}$ and the \docWIFI{} quality factor.
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To prevent sample impoverishment we extend this transition strategy by making the reachable area depended upon $D_\text{KL}$ and the \docWIFI{} quality factor.
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Particles are thus drawn uniformly on a sub-region of the mesh, given by a radius $ r_\text{sub} = D_\text{KL} \cdot q(\mObsVec_t^{\mRssiVec_\text{wifi}})$.
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The sub-region consists of all walk-able and connected triangles within $r_\text{sub}$, including stairs and elevators.
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%\todo{radius ist falsch! all connected triangles... warte aber noch aufs franks transition teil.}
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