To detect the region of interest (ROI), after creating a magnitude image in K-space data, the task of separating the object from the background is processed.
This unwrapped phase image is used to create a phase mask that is used to multiply the original magnitude image to create novel contrasts in the magnitude image.
All the processing steps involved in the creation of susceptibility weighted magnitude images are schematically summarized in Fig.
Figure 1 shows an example of (a) original face image, (b) gradient
magnitude image, and (c) the histogram of gradient magnitude.
It has little influence on the magnitude image, but it may destroy the joint probability density function (PDF) of magnitude and phase in the interferometric image as explained in Section 2.
The magnitude distribution remains nearly the same, so under this interference the magnitude image still has good quality.
The strong interferences in the magnitude image in the time domain of Figure 2(a) has been suppressed by channel equalization during imaging processing by NCSA.
Then, a region presenting a marked pitch in the gradient
magnitude image will grow the same as another one with smaller or no pitch.
