Object Tracking in SWIR Imaging Based on Both Correlation and Robust Kalman Filters

Short-wave infrared (SWIR) imaging has significant advantages in challenging propagation conditions where the effectiveness of visible-light and thermal imaging is limited. Object tracking in SWIR imaging is particularly difficult due to lack of color information, but also because of occlusions and maneuvers of the tracked object. This paper proposes a new algorithm for object tracking in SWIR imaging, using a kernelized correlation filter (KCF) as a basic tracker. To overcome occlusions, the paper proposes the use of the Kalman filter as a predictor and a method to expand the object search area. Expanding the object search area helps in better re-detection of the object after occlusion, but also leads to the occasional appearance of errors in measurement data that can lead to object loss. These errors can be treated as outliers. To cope with outliers, Huber’s M-robust approach is applied, so this paper proposes robustification of the Kalman filter by introducing a nonlinear Huber’s influence function in the Kalman filter estimation step. However, robustness to outliers comes at the cost of reduced estimator efficiency. To make a balance between desired estimator efficiency and resistance to outliers, a new adaptive M-robustified Kalman filter is proposed. This is achieved by adjusting the saturation threshold of the influence function using the detection confidence information from the basic KCF tracker. Experimental results on the created dataset of SWIR video sequences indicate that the proposed algorithm achieves a better performance than state-of-the-art trackers in tracking the maneuvering object in the presence of occlusions.