A fast quaternion wavelet-based motion compensated frame rate up-conversion with fuzzy smoothing: application to echocardiography temporal enhancement

In this paper, we propose a fast Frame Rate Up-Conversion (FRUC) method based on Quaternion Wavelet Transform (QWT) motion estimation to improve the motion estimation accuracy and reduce the computational complexity. The proposed method contains three key elements: motion estimation, motion post-processing, and motion compensated frame interpolation. This paper considers the QWT motion estimation using the phase of image sequences, which leads to more accurate motion estimation, less post-processing procedures, and low complexity as well. Moreover, we proposed a modified fuzzy vector mean filtering to cope with motion outliers and made use of bilateral motion vector modification in the post-processing part. We have assessed our proposed method performance using six widely available benchmark test sequences and three echocardiography image sequences. The evaluations confirm that while our proposed method keeps the PSNR and SSIM performance suitable, it is at least twice faster in comparison with reference methods on the benchmark dataset. The echocardiography evaluations reveal our proposed method superiority in terms of PSNR, SSIM, and computation time, which make the proposed method suitable as an echocardiographic-specific method.