this is for holding javascript data
Martin Coath edited section_Methods_subsection_Algorithm_For__.tex
about 8 years ago
Commit id: f642e2f38d7b4323d55171597d7fd887afab18fd
deletions | additions
diff --git a/section_Methods_subsection_Algorithm_For__.tex b/section_Methods_subsection_Algorithm_For__.tex
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\begin{enumerate}
\item the number of pixels $m$ corresponding to half the required window size $w$ is calculated: $m = \mathrm{floor}(\frac{w}{2})$
\item hence the working window size is $n = 2 \cdot m+1$ even when this differs from $w$ by one
\item assemble the
horizontal vector
$\vec{k}_{j}$ $\vec{k}_{h}$ of values for a
horizontal window of $n$
contiguous pixels $k_{[i,j-m \: : \: i,j+m]}$
\item repeat with
$\vec{k}_{i}$, $\vec{k}_{v}$, a vector of values for a vertical window of $n$ pixels $k_{[i-m,j \: : \: i+m,j]}$
\item both vectors are normalized, so they can be treated as distributions, and the Skewness $\gamma$ of each distribution (\textit{i.e.} a measure of the asymmetry in the gray-scale values in both direction) is calculated,
$\gamma_j$ $\gamma_h$ and
$\gamma_i$ $\gamma_v$
\item the \textsc{skv} value of the pixel
$\gamma_{i,j}$ is the
larger mean of the two values $\frac{\gamma_j + \gamma_i}{2}$
\end{enumerate}
In order to compare results from a range of pictures the window size will not be reported in pixels, but as the number of windows along the longest side of the image. For example, if a picture is 640 $\times$ 480 pixels and the \textsc{skv} is calculated with a window size of 64 pixels then this will be written as \textsc{skv}$_{10}$ as there are 10 windows along the longest side.