Biochips – fundamentals and applications - Electrochemical Sensors, Biosensors and Their Biomedical Applications - page 325

FIGURE 11.19

Fixed circle segmentation (see Plate 9 for color version).

FIGURE 11.20

Spots with different sizes (see Plate 10 for color version).

obtained (Fig. 11.21). This method will be a little tricky if the shape of the spot is non-
circular as shown in Fig. 11.22. For an irregularly shaped spot, a circular spot mask
is impractical as it provides a poor fi t to the spot. In the adaptive shape segmentation
method, no assumption of the shape of the spot is made. A small number of pixels,
known as seeds, are selected from within the spot (Fig. 11.22). At each step of the
algorithm, the selected region is grown outward by adding a pixel to the existing seed
according to the difference between the seed pixel's value and the running mean of the
values in an adjoining region. In histogram segmentation, a target mask larger than any
spot is used. Within the target mask, the foreground and background intensities are deter-
mined. For pixel values greater than a predetermined threshold, the pixel is classifi ed