Figure 7
Time-lapse processing. (a) A polar transformation is applied to grayscale sub-images of each colony and intensity values are averaged over the radius for each frame in the time-lapse. These radial average intensity vectors are combined into a kymograph representing colony radius growth. (b) Overlapping colonies result in blurry regions in the top part of the kymograph. The angle range corresponding to overlapping colonies is excluded to reduce this effect. Kymographs can be processed either by (c) Global thresholding or (d) Edge detection method. (c) In the Global thresholding method, a threshold is applied to a filtered version of the kymograph to derive a binary image. (d) The Edge detection method uses a series of filtering steps, edge detection algorithms and morphological operations to optimize the binary image.
