Figure 4.

(a) The participation weight for each gradient direction is determined based on its angular distance from the current direction; (b) Same‐location spatial group patches from 3 gradient directions as well as the current direction. Two of the gradient directions (blue and green) are within the angular distance threshold based on figure (a) and are included in patch reconstruction. On the other hand, the red direction is excluded. [Color figure can be viewed at http://wileyonlinelibrary.com]