Content deleted Content added
m correcting ref |
converted to math formula |
||
Line 1:
'''Local ternary patterns''' (LTP) is an extension of the [[Local binary patterns]] introduced by <ref>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</ref>. 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:<br />
<math>
\begin{cases}
0 if c>p-k and c<p+k▼
▲0, & \text{if } c>p-k \text{ and } c<p+k \\
-1 & \text{if } c<p-k \\
\end{cases}
</math>
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.
| |||