A Novel Technique for Prealignment in Multimodality Medical Image Registration
Figure 3
Local gradient calculated by the Gaussian derivative and gradient derivative, respectively. (a) Original image and its portion shown by the red rectangle. (b) Local gradient by Gaussian derivative. (c) Local gradient by gradient derivative. Note that the blue axis shows the local gradient orientation at each pixel, and the length of the axis denotes the value of local gradient magnitude.
