Exact order based feature descriptor for illumination robust image matching

•To resolve ordering ambiguity for pixels, an exact order image created.•Exact order based features are generated globally and locally.•Descriptor is constructed by combining the global and local exact order features.

We present a novel method for a feature descriptor called an exact order based descriptor (EOD). The proposed method consists of three steps. First, to resolve ordering ambiguity for pixels of the same intensity, an exact order image is created by changing the discrete intensity into a k-dimensional continuous value. Second, exact order based features are generated globally and locally. Finally, the EOD is constructed by combining the global and local exact order features using the discrete cosine transform. Experimental results show that the proposed method outperforms other state-of-the-art descriptors over a number of images.