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Features Calculated Using the Convex Hull of the Protein Fluorescence

The convex hull of the protein localization image was calculated using the convhull function in Matlab and converted to a binary image.

The fraction of the convex hull area occupied by protein fluorescence

The roundness of the convex hull

\begin{displaymath}\frac{(Perimeter)^2}{4\pi Area}
\end{displaymath} (3.6)

The eccentricity of the convex hull
The eccentricity of the ellipse equivalent, based on second order moments, to the protein image convex hull was calculated using [49]

 \begin{displaymath}\frac{\sqrt{(Semimajor Axis)^2 - (Semiminor Axis)^2}}{(Semimajor
Axis)}
\end{displaymath} (3.7)

where

\begin{displaymath}Semimajor Axis = \sqrt\frac{2[\mu_{20}+\mu_{02}+
\sqrt{(\mu_{20}-\mu_{02})^2 + 4\mu_{11}^2}]}{\mu_{00}}
\end{displaymath} (3.8)

and

\begin{displaymath}Semiminor Axis = \sqrt\frac{2[\mu_{20}+\mu_{02}-
\sqrt{(\mu_{20}-\mu_{02})^2 + 4\mu_{11}^2}]}{\mu_{00}}
\end{displaymath} (3.9)

(The $\mu_{xy}$ above are the central moments of the image intensity function).


next up previous contents
Next: Feature Selection Up: ad hoc features Previous: Features Calculated Using Both
Copyright ©1999 Michael V. Boland
1999-09-18