Local ternary patterns
Local ternary patterns (LTP) is an extension of the Local binary patterns introduced by [1]. Unlike LBP, it does not threshold the pixels into 0 and 1, rather it uses a threshold constant to threshold pixels into three values. Considering k as the threshold constant, c as the value of the center pixel, a neighboring pixel p, the result of threshold is: 1 if c>p+k 0 if c>p-k and c<p+k -1 if c<p-k.
In this way, each thresholded pixel has one of the three values. Neighboring pixels are combined after thresholding into a ternary pattern. Computing a histogram of these ternary values will result in a large range, so the ternary pattern is split into two binary patterns. Histograms are concatenated to generate a descriptor double the size of LBP.
Related
References
- ^ Xiaoyang Tan and Bill Triggs Enhanced Local Texture Feature Sets for Face Recognition Under Difficult Lighting Conditions, IEEE Transactions on Image Processing, 19(6), pp. 1635-1650, 2010