(a) Spatial filtering and colony counting. Raw plate image captured by the imaging camera. (b) Separation of colonies by subtracting the pre-saved background image and applying threshold. (c) Identification of colonies to be scanned by marking with blue color. (i) Colonies with too small or large diameters; (ii) colonies with low roundness values (indicating two or more intersecting colonies); (iii) colonies too close to the black hole in the raw plate image.