Figure 1.

(a) How the s × s pixels image patch is divided into blocks. (b) The plot of p_EHPG (u_r, u_θ, b) for each block. x-axis represents u_r and y-axis represents u_θ. Dark areas represent areas of high probabilities. Notice that windows around u_r ≈ 0 and u_θ ≈0 at block b = 5 are sampled at high frequency. (c) That F-score for classification increases with the use of p_EHPG for sampling windows w_i. The right table shows the ranges of u_r, u_θ and b values in which histogram counts are accumulated for HPG features