Worm Features

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Features

Worms are tracked according to their distance from the pheromone spots and intrinsic features are computed from the image data for each worm.

Name	Description	Formula
Width	Model of worm Width	$\overline{w}\times(1-e^{-0.1\times(m-\|2i-m\|)})$
Area	Number of pixels in the worm	$\| Ω \|$
Minor Length	Minor axis length of an ellipse with the same area as the worm which has been fit to our worm model	$4\sqrt{\lambda_0}$
Major Length	Major axis length of an ellipse with the same area as the worm which has been fit to our worm model	$4\sqrt{\lambda_1}$
Eccentricity	Ratio of maximum to minimum distance of the center of mass from the worm’s surface	$\cfrac{\max(\sqrt{\|\|p-\overline{p}\|\|})}{\min(\sqrt{\|\|p-\overline{p}\|\|})}$
Orientation	Angle between the first principal axis of a given worm and the ‘x’ axis	$\arctan[\cfrac{dy}{dx}]$
t_start	Frame number that worm was initially detected	$F t (0)$
t_end	Frame number that worm was last detected	$F_t(\infty)$
t_length	Total number of frames worm was tracked in a given image sequence	$\sum_t F_t, F = \# of frames$
Curvature	A metric to give an estimate of coiling as a worm behavior	$\kappa = (\cfrac{\theta_i}{L})$
Sum Squared Curvature	Average Curvature squared, gives an estimate of the worm’s bending energy	$\sum_{i,t} mean(\cfrac{\theta_i^t}{L})$
Intensity	The average intensity of the pixels in a worm	$m e a n ( \| Ω \| )$
Worm_Velocity	The average worm speed	$m e a n ([u i,..., u n])$ i=1,2,...,15
Peri_std	The standard deviation of the worm speed. Gives users insight into irregularities of worm peristaltic progression	$s t d ([u i,..., u n])$ i=1,2,...,15
D_head_std	Standard deviation of the displacement of the worm’s head	$std(\gamma_k^H= {\tilde{\gamma}}^H \times e^{-0.09 \times (m-k)})$
D_tail_std	Standard deviation of the displacement of the worm’s tail	$std(\gamma_k^T= {\tilde{\gamma}}^T \times e^{-0.72 \times (k)})$
Reversal Rate	The frequency of backward progression by the worm’s head	$\cfrac{\|\|\sum u_i\|\|}{\sum \|\|u_i\|\|}$
Class	Each Phenotype is given a separate class from 1-N	$N / A$
Bearing	The angle between the velocity vector and the spatial vector from the worm’s position to the center of the pheromone spot(chemical gradient)	$\theta = \arctan[\cfrac{dv}{ds}]$
Instantaneous Turning Rate	The change in orientation over time	$[\cfrac{d\phi}{dt}]$

Worm Features

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