Title: An Automatic and Robust Visual SLAM Method for Intra-Abdominal Environment Reconstruction | Keywords: stereo laparoscope, 3D reconstruction, stereo matching, feature tracking, kernel correlation filter | Author: Guodong Wei, Weili Shi, Guanyuan Feng, Yu Ao, Yu Miao, Wei He, Tao Chen, Yao Wang, Bai Ji, and Zhengang Jiang

Color is an essential feature in histogram-based matching. This can be extracted as statistical data during the comparison process. Although the applicability of color features in histogram-based techniques has been proven, position information is lacking during the matching process. We present a conceptually simple and effective method called multiple-layered absent color indexing (ABC-ML) for template matching. Apparent and absent color histograms are obtained from the original color histogram, where the absent colors belong to low-frequency or vacant bins. To determine the color range of compared images, we propose a total color space (TCS) that can determine the operating range of the histogram bins. Furthermore, we invert the absent colors to obtain the properties of these colors using threshold $h_{\mathrm{T}}$. Then, we compute the similarity using the intersection. A multiple-layered structure is proposed against the shift issue in histogram-based approaches. Each layer is constructed using the isotonic principle. Thus, absent color indexing and multiple-layered structure are combined to solve the precision problem. Our experiments on real-world images and open data demonstrated that they have produced state-of-the-art results. Moreover, they retained the histogram merits of robustness in cases of deformation and scaling.