In this article, phase of the Fourier transform (FT), which has observed to be a crucial component in image representation, is utilized for visual target tracking. The main aim of the proposed scheme is to reduce the computational complexity of crosscorrelation-based matching frameworks. Normalized cross-correlation (NCC) function-based object tracker is converted to a phase minimization problem under the following assumption: In visual object tracking applications, if the frame rate is high, the moving object can be considered to have translational shifts in image domain in a small time window. Since the proposed tracking framework works in the Fourier domain, the translational shifts in the image space are converted to phase variations in the Fourier domain due to the "translational invariance" property of the FT. The proposed algorithm estimates the spatial target position based on the phase information of the target region. The proposed framework uses the 1 -norm and provides a computationally efficient solution for the tracking problem. Experimental studies indicate that the proposed phase-based technique obtain comparable results with baseline tracking algorithms which are computationally more complex.
KeywordsImage phase information • Visual target tracking • Phase spectrum • Fourier transform • 1 -norm 1 Related work on visual target tracking techniques Visual object tracking is an important research area in the field of computer vision [1] which is utilized for various applications including surveillance [2], laser designation [3], transportation safety [4], human-computer interaction [5], and medical analysis [6]. Visual tracking problem is generally defined as the estimation of the target location in the image given some initial conditions such as the initial position and size of the target. During target tracking, position estimation may become difficult due to occlusions by other objects, object shape deformations, motion blur caused by rapid movements, illumination variations, low contrast between foreground and background, and changes in object scale [1].