|
|
@ -1,17 +1,17 @@ |
|
|
|
\section{Method name} |
|
|
|
\section{System Architecture} |
|
|
|
\label{sec:design} |
|
|
|
|
|
|
|
\subsection{System Architecture} |
|
|
|
We designed a thermal-box to collect the data. It has four Grideye sensors on the |
|
|
|
corners of a 10 cm square and a Lepton 3 at the central. Figure~\ref{fig:method} shows |
|
|
|
the system of our method. It consists four parts. The first part is to fuse multiple |
|
|
|
Grideye image, since the resolution of single Grideye sensor only has 64 pixels. The |
|
|
|
data from Grideye sensors into a low-resolution image, since the resolution of a |
|
|
|
single Grideye sensor too low to make a decision. The |
|
|
|
second part, we train the SRCNN model with fused Grideye image |
|
|
|
as low-resolution and downscaled Lepton 3 image as high-resolution image. |
|
|
|
The third part, we use the |
|
|
|
Super-resolution image to train a neural network model for recognizing current pose |
|
|
|
is lay on back or lay on side. The last part, because of noise and the residual |
|
|
|
heat on bed after turn over, it is difficult to figure out the current pose. We |
|
|
|
is lay on back or lay on side. The last part, to reduce the noise and effect cause by |
|
|
|
the residual heat on bed after turning over. We |
|
|
|
remove the noise by median filter, and determine the current pose according to |
|
|
|
the trend of the possibility from recognition network. |
|
|
|
|
|
|
@ -30,7 +30,8 @@ the thermal-box faces to an empty bed and records the background temperature. |
|
|
|
All the following frames will subtract this background temperature. After that, |
|
|
|
we resize four $8 \times 8$ Grideye images to $64 \times 64$ by bilinear |
|
|
|
interpolation and then merge them dependence on the distance between thermal-box and |
|
|
|
bed, width of sensor square and the FOV of Grideye sensor. |
|
|
|
bed, distance between sensors and the FOV of Grideye sensor. In our case, $D_B$ is |
|
|
|
150 cm, and $D_s$ is 10 cm. |
|
|
|
|
|
|
|
\begin{enumerate} |
|
|
|
\item $D_b$ is the distance between bed and thermal-box. |
|
|
@ -39,27 +40,28 @@ bed, width of sensor square and the FOV of Grideye sensor. |
|
|
|
\item $Overlap = 64 - 64 \times (\frac{D_s}{2 \times D_b \times tan(\frac{F}{2})})$ |
|
|
|
\end{enumerate} |
|
|
|
|
|
|
|
\subsection{Pose determination} |
|
|
|
\subsection{Turning Over Determination} |
|
|
|
|
|
|
|
We train a SRCNN model by the fused Grideye data and downscaled Lepton 3 image, |
|
|
|
and use it to upscale all following frames to SR frames. We labeled some SR frames |
|
|
|
to two categories. One is lay on back and the other is lay on side. Since the input |
|
|
|
We train a SRCNN model by the fused Grideye image and downscaled Lepton 3 image, |
|
|
|
and use it to enhance all following Grideye frames to SR frames. We labeled some SR frames |
|
|
|
into two categories, lay on back and lay on side. Since the input |
|
|
|
data is very small, we use a neural network consist one 2D convolution layer, one |
|
|
|
2D max pooling, one flatten and one densely-connected layer. The possibility of |
|
|
|
output has a very large various just after turning over because the model cannot |
|
|
|
output has a very large various just after turn over because the model cannot |
|
|
|
distinguish the residual heat on bed and the person as Figure~\ref{fig:residual_heat} shown. This |
|
|
|
situation will slowly disappear after one or two minutes. |
|
|
|
|
|
|
|
To determination the pose, first we use a median filter with a window size of five |
|
|
|
to filter out the noise. Then, find the curve hull line of the upper bound and |
|
|
|
lower bound of the data. Finally, calculate the middle line of upper bound and lower bound. |
|
|
|
Figure~\ref{fig:trend} shows the data and these lines. |
|
|
|
lower bound of the data. Finally, calculate the middle line of upper bound and |
|
|
|
lower bound, and regrad it as the trend of the pose changing. Figure~\ref{fig:trend} |
|
|
|
shows the filitered data and these lines. |
|
|
|
|
|
|
|
We divide every data into 10 second time windows. If the middle line of the time window |
|
|
|
is at the top one fifth, it is a lay on back. If it is at the bottom one fifth, |
|
|
|
it is a lay on side. If the trend of line is going up, it is lay on back. Otherwise, it |
|
|
|
is lay on side. To guarantee the confidence of result, we will only trust the pose if |
|
|
|
there are three continuously same output. |
|
|
|
is at the top one fifth, or the trend is going up, it is a lay on back. If it is at the |
|
|
|
bottom one fifth, or the trend is going down, it is a lay on side. If there are three |
|
|
|
continuously same poses, and different from the last turning over, it will be count as |
|
|
|
another turning over. |
|
|
|
|
|
|
|
\begin{figure}[ht] |
|
|
|
\centering |
|
|
|