**4. Implementation of LBP-based IDW method**

We consider a resolution of 128 � 128 pixels for face images of the selected databases and face preprocessing is performed on all the face images. Thus each one of the IDW sub-bands LL, HL, LH f g is of size 32 � 32 pixels and each sub-band is divided into m ¼ 16 regions with the size of each region as x � y ¼ 8 � 8 pixels [18]. We applied LBP to each of the regions from each of the sub-bands f g LL, HL, LH . We used the uniform pattern LBPu2 8,1 [7] and NN classifier with Chisquare distance measure. This form an enhanced feature vector or descriptor *EFV* with a combined dimension as 59 � m � 3 ¼ 2832 [18]. The algorithm representing the proposed method is presented in Algorithm 1.
