Artificial Intelligence and Soft Computing: Behavioral ... - Arteimi.info

1. Move the mask over the image, so that the central (x, y) pixel of the
mask is merged with a pixel of the image. The boundary pixels of
the image, however, cannot not be merged with the central pixel of
the mask.
2. Evaluate the changed gray level at pixel (x, y) by taking the sum of
the product of the mask weights and the gray level at the
corresponding pixels and save it.
3. If all feasible pixels on the image have been visited, replace the old
gray levels by the corresponding new (saved) values and stop, else
continue from step 1.
Among the other smoothing algorithms, most common are mean and
median filters. The mean filter takes the average of the gray levels of all 8neighboring
pixels to compute the changed gray level at pixel (x, y). The
median filter, on the other hand, replaces the current gray level of pixel (x, y)
by the median of its 8 neighborhood pixels. Experimental evidences show that
mean filter blurs the image, but the median filter enhances the sharpness of
the image.
17.2.2 Finding Edges in an Image
An edge is a contour of pixels that (artificially) separates two regions of
different intensities. It also can be defined as a contour along which the
brightness in the image changes abruptly. Fig. 17.3 describes the edges in a
synthetic image.
Fig. 17.3: Edges in a synthetic image.
edges