Figure 4.19(a) shows a chest X-ray image, f. X-ray imagers cannot be focused in the same manner as optical lenses, so the resulting images generally tend to be slightly blurred. The objective of this example is to sharpen
Fig. 4.19(a). Because the gray levels in this particular image are biased toward the dark end of the gray scale, we also take this opportunity to give an example of how spatial domain processing can be used to complement frequency domain filtering. G