Algorithm 1 Skip Frame for Fire-Tube Generation

$F\text{-}Tube$: A set of fire-tubes

Initialize $F\text{-}Tube=\varnothing$, N: size of F-Tube

$Ho{F}_{mag}$: Magnitude of HoF

th: a threshold for skip frame selection

k: index of fire-tube, i: index of current candidate frame (i > N (50))

K = 0, $F\text{-}Tube\left[\mathrm{k}\right]=\mathrm{frame}\left(\mathrm{i}\right)$

i--

Do

$\mathrm{If}\mathrm{frame}\left(\mathrm{i}\right)==fire \& \left|\mathbf{F}\text{-}\mathbf{T}\mathbf{u}\mathbf{b}\mathbf{e}\left[\mathrm{k}\right].{\mathrm{HoF}}_{\mathrm{mag}}-\mathrm{HoF}{\left(\mathrm{i}\right)}_{\mathrm{mag}}\right|\ge th$

Then

F-Tube [k] = frame (i)

k++, i--

Else

i--//skip frame

While (No. of frames of F-Tube is full)