hullFeatures             package:EBImage             R Documentation

_E_x_t_r_a_c_t_i_o_n _o_f _h_u_l_l _f_e_a_t_u_r_e_s _f_r_o_m _i_m_a_g_e_s _o_f _i_n_d_e_x_e_d _o_b_j_e_c_t_s

_D_e_s_c_r_i_p_t_i_o_n:

     Hull features are a set of numeric descriptors of the hull of an
     object. These include coordinates, perimeter, size, acircularity
     etc.

_U_s_a_g_e:

       ## S4 method for signature 'IndexedImage':
       hullFeatures(x, ...)
       

_A_r_g_u_m_e_n_t_s:

       x: An object of 'IndexedImage'.

     ...: Reserved. 

_D_e_t_a_i_l_s:

     The extracted features are (names carry an 'h.' prefix to indicate
     hull features): 'x,y' - coordinates of the geometric center, 's' -
     size (area), 'p' - perimeter, 'pdm' - mean distance to perimeter
     (from the center), 'pdsd' - standard deviation of the distance to
     perimeter, 'effr' -  effective radius (is the radius of a circle
     with the same area), 'acirc' - acircularity (fraction of pixels
     outside of the circle with 'r=reff'),  'sf' - shape factor ('per /
     ( 2 * sqrt(Pi * s))'), 'edge' -  number of pixels at the edge of
     the image, 'theta' - hull's rotation angle (calculated without
     taking intensity values into account), 's2maj' - 2 times semi
     major (square root of the larger eigenvalue of the  'moments'
     covariance matrix) - correlates with the distance from the center
     to the edge along the major axis, 's2min' - same but for the 
     smaller eigenvalue (minor axis), 'ecc' - eccentricity 
     ('sqrt(eig1-eig2)/smaj'), 'I1, I2' - first and second rotation
     invariant moments of the hull (as in 'moments').

_V_a_l_u_e:

     For a single frame, a matrix of descriptors with objects in rows
     and features in columns. For image stacks, a list of such
     matrices.

_A_u_t_h_o_r(_s):

     Oleg Sklyar, osklyar@ebi.ac.uk, 2007

_S_e_e _A_l_s_o:

     ' IndexedImage, watershed, getFeatures,  edgeFeatures, moments '

_E_x_a_m_p_l_e_s:

       ## see example(getFeatures)

