Concluding Remarks

This chapter has focused on fundamental enhancement techniques used on medical and dental images. These techniques have been effective in many applications and are commonly used in practice. Typically, the techniques presented in this chapter form a first line of algorithms in attempts to

FIGURE 9 Filtering with the Butterworth filter. (a) Fourier transform of MRI image in (e); the five circles correspond to the 3 values 75, 90, 95, 99, and 99.5%. (b) Fourier transform of low-pass filter with 3 = 90% which provides the output image in (f). (c) Band-pass filter with band 3 = 75% to 3 = 90% whose output is in (g). (d) High-pass filter with 3 = 95%, which yields the image in (h). (Courtesy of Dr. Patricia Murphy, Johns Hopkins University Applied Physics Laboratory.)

FIGURE 9 Filtering with the Butterworth filter. (a) Fourier transform of MRI image in (e); the five circles correspond to the 3 values 75, 90, 95, 99, and 99.5%. (b) Fourier transform of low-pass filter with 3 = 90% which provides the output image in (f). (c) Band-pass filter with band 3 = 75% to 3 = 90% whose output is in (g). (d) High-pass filter with 3 = 95%, which yields the image in (h). (Courtesy of Dr. Patricia Murphy, Johns Hopkins University Applied Physics Laboratory.)

enhance image information. After these algorithms have been applied and adjusted for best outcome, additional image enhancement may be required to improve image quality further. Computationally more intensive algorithms may then be considered to take advantage of context-based and object-based information in the image. Examples and discussions of such techniques are presented in subsequent chapters.

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