<html><head><meta name="color-scheme" content="light dark"></head><body><pre style="word-wrap: break-word; white-space: pre-wrap;">%========================================================================
\section{Hazard Resemblance Factors}
\label{sec_hazard_resemble}
%========================================================================

Benign objects may contain an additional {\em resemblance factor} in
the range of $[0,1]$, where zero indicates the object shares very
little resemblance to a hazard, and vice versa for values of one.
Each benign object $i$ in the hazard file has an associated
resemblance factor $R_i$. When the \var{uFldHazardSensor} application
publishes visual markers for benign objects, it reflects the hazard
resemblance factor in the marker transparancy. A benign object with
hazard resemblance of $0.64$ might be posted as:

\prevgreen
\begin{verbatim}
  VIEW_MARKER = x=7,y=89,width=8,primary_color=light_blue,type=triangle,label=991,
                fill_transparency=0.64 
\end{verbatim}
\postverb

\noindent
The overall rendering of the hazard field in \app{pMarineViewer} may
look something similar to that in Figure \ref{fig_resemble}.

\vspace{0.1in}
\begin{figure}[H]
  \centering 
  \includegraphics[width=0.8\textwidth]{figures/resemble.png}
  \caption{{\bf A simulated hazard field with resemblance factors:}
    Green markers represent hazards. Light blue markers represent benign
    objects. The more transparent the markers, the lower the resemblance
    factor. The resemblance factor ranges from $[0,1]$.}
  \label{fig_resemble}
\end{figure}

%---------------------------------------------------------------------
\subsection*{Influence of Resemblance Factor on $\pfa$}

The probability of a detection declared on a benign object (a false
alarm), is normally given by $\pfa$. The hazard resemblance factor
is further applied to provide a unique probability of false alarm for
a given object $i$.

$$P_{FA}(i) = (P_{FA} + R_i) / 2$$

\vspace{0.1in}
\noindent
The exception is when $P_{FA}1$. In this case $P_{FA}(i)$ is also 1.


%---------------------------------------------------------------------
\subsection*{Influence of Resemblance Factor on $\pc$}

The probability of a correct classification on a given object is
normally given by $\pc$, in the range of $[0.5,1]$. The hazard
resemblance factor is further applied to provide a unique probability
of correct classification for a given object $i$.  

$$P_{C}(i) = P_{C} + (1-P_C)(1-R_i)$$

\vspace{0.1in}
\noindent
In short, $P_C(i)$, at worst, is given by $\pc$ for objects closely
resembling a hazard ($R_i=1$), and $\pc$ approaches 1, i.e.,
perfection, for objects that look nothing like a hazard ($R_i=0$).



</pre></body></html>