You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
50 lines
2.3 KiB
50 lines
2.3 KiB
\section{Performance Evaluation}
|
|
\label{sec:eval}
|
|
|
|
To evaluate the effectiveness of the proposed method, we did the different ratios of compressing on a thermal data by our method compared to JPEG image using different quality and png image, a lossless bit map image. We set the camera at the ceiling and view direction is perpendicular to the ground, and the thermal data size is $480 \times 640$ pixels. The JPEG image is generated by OpenCV $3.3.0$ which is using libjpeg version 9 13-Jan-2013, and image quality from $1$ to $99$.
|
|
|
|
Figure~\ref{fig:4KMy} and Figure~\ref{fig:4KJpeg} show the different of JPEG and our method. JPEG image id generated by image quality level $3$, and thermal data of our method does $1390$ rounds of separate and compressed by Huffman Coding. In this case, Huffman Coding can reduce $39\%$ of compressed data size.
|
|
|
|
\begin{figure}[ht]
|
|
\begin{minipage}[b]{0.45\linewidth}
|
|
\centering
|
|
\includegraphics[width=\linewidth]{figures/my4000.png}
|
|
\caption{Data compressed by Proposed Method (4KB)}
|
|
\label{fig:4KMy}
|
|
\end{minipage}
|
|
\hspace{0.05\linewidth}
|
|
\begin{minipage}[b]{0.45\linewidth}
|
|
\centering
|
|
\includegraphics[width=\linewidth]{figures/quality3.jpg}
|
|
\caption{Data compressed by JPEG (4KB)}
|
|
\label{fig:4KJpeg}
|
|
\end{minipage}
|
|
\end{figure}
|
|
|
|
Figure~\ref{fig:compareToJpeg} shows that the size of file can reduce more than $50\%$ compared to JPEG image when both have $0.5\% (0.18^\circ C)$ of root-mean-square error. Our method has $82\%$ less error rate when the compressed data size is $4KB$. The percentage of file size is compared to PNG image.
|
|
|
|
\begin{figure}[ht]
|
|
\centering
|
|
\includegraphics[width=\columnwidth]{figures/compareToJpeg.pdf}
|
|
\caption{Proposed method and JPEG comparing}
|
|
\label{fig:compareToJpeg}
|
|
\end{figure}
|
|
|
|
The computing time of a $480 \times 640$ thermal data on Raspberry Pi 3 is:
|
|
\subsubsection{Date Structure Initialize}
|
|
0.233997 second.
|
|
\subsubsection{Thermal Data Loading}
|
|
1.268126 second.
|
|
\subsubsection{Regions dividing}
|
|
About 4.6 microsecond per separation. Figure~\ref{fig:computeTime} shows the computation time of Region dividing.
|
|
|
|
Total time is about 1.5 second.
|
|
|
|
\begin{figure}[ht]
|
|
\centering
|
|
\includegraphics[width=\columnwidth]{figures/computeTime.pdf}
|
|
\caption{Computation Time of Regions Dividing}
|
|
\label{fig:computeTime}
|
|
\end{figure}
|
|
|
|
|