Cell model. (a) The proposed cell model (8) assumes a uniform zero-mean background. A cell is modelled by the product of P
, the cell probability based on cell interior and P
, the penalizing probability based on outer cell ring. Not all pixels surrounding a cell are necessarily background, however we expect at least some fraction as background, and penalize (P
) the mean-square deviation from zero (P
) of this fraction. The fraction of background pixels which are located between two rings with radii r and 2 r are illustrated by solid lines for both phenotypes. (b) Cropped well interior: (i) Cropped well interior with no well boundaries. (ii) Applying the cell model to (i).