Algorithm 1.

Spatiotemporal mixed particle filter.

procedure $({\{{\{x_{k,l}^j,w_{k,l}^j\}}_{j=1}^{N_s}\}}_{l=1}^4)=$SMPF (${\{{\{x_{k-1,l}^j,w_{k,l}^j\}}_{j=1}^{N_s}\}}_{l=1}^4$, {ΔTr,k})

Calculate ${\left\{E{T}_{k.l}\right\}}_{l=1}^4$ based on {ΔTr,k}

for l ← 1:4 do

for i ← (0, 0):(239, 179) do

if number of events in the i-th pixel < 3 then

ETi,k,l ← 0

end if

end for

end for

for l ← 1:4 do

for j ← 1:Ns do

Draw $x_{k,l}^j~p(x_{k,l}|x_{k-1,l}^j)=N(x_{k-1,l}^j,I{\sigma }^2)$

Get the particle's temporal evidence ETi,k,l according to $x_{k,l}^j$

end for

end for

for l ← 1:4 do

Nreselect ← Equation (5)

if Nreselect < Thl then

Run reselection (replacement)

Get the new particle set ${\{x_{k,l}^j\}}_{j=1}^{N_s}$ and the new temporal evidence set ${\left\{E{T}_{i,k,l}\right\}}_{i=1}^{N_s}$

for j ← 1:Ns do

$w_{k-1,l}^j\leftarrow 1/N_s$

end for

end if

Normalize ${\left\{E{T}_{i,k,l}\right\}}_{i=1}^{N_s}$

Calculate μTk,l and ΣTk,l of the temporal evidence matrix ETk,l

for j ← 1:Ns do

Get spatial evidence ESi,k,l according to $x_{k,l}^j$, $E{S}_{i,k,l}=N(x_{k,l}^j|\mu T_{k,l},\Sigma T_{k,l})$

end for

Normalize ${\{E{S}_{i,k,l}\}}_{i=1}^{N_s}$

for j ← 1:Ns do

Update the particle's weight $w_{k,l}^j=w_{k-1,l}^j\times (E{T}_{i,k,l}+\alpha \times E{S}_{i,k,l})$

end for

Normalize ${\{w_{k,l}^j\}}_{j=1}^{N_s}$

Neff ← Equation (7)

if Neff < Theff × Ns then

Run resampling

Get the new particle set ${\{x_{k,l}^j\}}_{j=1}^{N_s}$

for j ← 1:Ns do

$w_{k,l}^j\leftarrow 1/N_s$

end for

end if

Update the tracked position of the l-th LED marker, $x_{LED,k,l}=\sum _{j=1}^{N_s}{w}_{k,l}^j\times x_{k,l}^j$

for j ← 1:Ns do

$w_{k-1,l}^j\leftarrow w_{k,l}^j$

end for

end for

end procedure