  In this paper, an adaptive pixel ternary coding mechanism is proposed and a
contrast invariant and noise resistant interest point detector is developed on
the basis of this mechanism. Every pixel in a local region is adaptively
encoded into one of the three statuses: bright, uncertain and dark. The blob
significance of the local region is measured by the spatial distribution of the
bright and dark pixels. Interest points are extracted from this blob
significance measurement. By labeling the statuses of ternary bright,
uncertain, and dark, the proposed detector shows more robustness to image noise
and quantization errors. Moreover, the adaptive strategy for the ternary
cording, which relies on two thresholds that automatically converge to the
median of the local region in measurement, enables this coding to be
insensitive to the image local contrast. As a result, the proposed detector is
invariant to illumination changes. The state-of-the-art results are achieved on
the standard datasets, and also in the face recognition application.
