Frame rate upconversion in cardiac ultrasound Abstract   The temporal resolution of echocardiographic sequences affects the interpretation of cardiac motion as well as the viewing experience. Temporal resolution, however, is limited by the propagation velocity of sound in tissue. Altering the acquisition system can improve temporal resolution but normally reduces image quality. Alternatively, motion compensated frame interpolation enhances perceived temporal resolution without reducing spatial resolution. There are however significant challenges with these techniques due to the simultaneous presence of large and small motions of the cardiac structures. In this paper, we propose a new motion compensated frame interpolation algorithm based on a variational bidirectional motion estimation model. We derive the EulerLagrange equations characterizing the optimal dense bidirectional motion field and develop a multiscale iterative procedure to obtain the motion field and the missing intermediate frames. The performance of the proposed algorithm was evaluated on real cardiac ultrasound recordings, using both subjective and objective evaluation criteria. Experimental results show that the interpolated frames generated by the proposed algorithm do not have the ghosting or blurring artifacts that are commonly present in the existing motion compensated frame interpolation algorithms, especially near fast moving structures like the cardiac valves. Quantitatively, the proposed algorithm achieves an improvement in the average peak signaltonoise ratio of 1.16 dB and in the structural similarity index of 3.0%.

Temporal superresolution of 2D3D echocardiography using cubic Bspline interpolation Abstract   Echocardiography is an important imaging modality in daily clinical practices. Lack of image quality and limited number of frames per second are the major problems of this modality. Frame rate limitation becomes worse in 3D echocardiography, because it has to scan a volume instead of a plane and acquisition of a volume consumes more time compared to its twodimensional counterpart. Higher frame rates can help improve medical diagnostics like tracking movements of cardiac valves and position of ventricular endocardial, myocardial and epicardial by tracing the small transient motions in order to better characterize the functionality of cardiac activities. There are a few numbers of temporal superresolution methods to improve the frame rate. Here, we have proposed a temporal interpolation method using splines. Comparison of the results with that of the stateoftheart methods shows promising outcomes to enhance echocardiography frame sequences in both two and threedimensional clinical echocardiography images. Results show that proposed method is doing interpolation more precisely and it also performs about ten times faster in the sense of processing time compared to the latest works to increase the frame rate. We have also shown that interpolation accuracy depends greatly on how many frames per second we have initially and how many frames we want to add to the original sequence. This frame rate increase is also applied to the color Doppler in both 2D and 3D echocardiography and results are presented.