3D left ventricular strain by phase unwrapping: A simulated annealing based branch-cut placement method

Ambale, B.; Denney, Thomas S.; Gupta, Himanshu; Lloyd, Steven G.; Dell’Italia, Louis J.

doi:10.1109/isbi.2009.5193085

Cited by 2 publications

(1 citation statement)

References 8 publications

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“…There are still other significant papers about phase unwrapping algorithms performed on sparse data [9] and 3D data [10]. Path following algorithms depend on the unwrapping path to guarantee the correctness of an unwrapped result, which is usually very efficient, while selection of a reliable unwrapping path is usually very difficult.…”

Section: Introductionmentioning

confidence: 99%

Phase quality map based on local multi-unwrapped results for two-dimensional phase unwrapping

2015

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The efficiency of a phase unwrapping algorithm and the reliability of the corresponding unwrapped result are two key problems in reconstructing the digital elevation model of a scene from its interferometric synthetic aperture radar (InSAR) or interferometric synthetic aperture sonar (InSAS) data. In this paper, a new phase quality map is designed and implemented in a graphic processing unit (GPU) environment, which greatly accelerates the unwrapping process of the quality-guided algorithm and enhances the correctness of the unwrapped result. In a local wrapped phase window, the center point is selected as the reference point, and then two unwrapped results are computed by integrating in two different simple ways. After the two local unwrapped results are computed, the total difference of the two unwrapped results is regarded as the phase quality value of the center point. In order to accelerate the computing process of the new proposed quality map, we have implemented it in a GPU environment. The wrapped phase data are first uploaded to the memory of a device, and then the kernel function is called in the device to compute the phase quality in parallel by blocks of threads. Unwrapping tests performed on the simulated and real InSAS data confirm the accuracy and efficiency of the proposed method.

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Section: Introductionmentioning

confidence: 99%

Phase quality map based on local multi-unwrapped results for two-dimensional phase unwrapping

2015

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Tile-Based Two-Dimensional Phase Unwrapping for Digital Holography Using a Modular Framework

et al. 2015

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A variety of physical and biomedical imaging techniques, such as digital holography, interferometric synthetic aperture radar (InSAR), or magnetic resonance imaging (MRI) enable measurement of the phase of a physical quantity additionally to its amplitude. However, the phase can commonly only be measured modulo 2π, as a so called wrapped phase map. Phase unwrapping is the process of obtaining the underlying physical phase map from the wrapped phase. Tile-based phase unwrapping algorithms operate by first tessellating the phase map, then unwrapping individual tiles, and finally merging them to a continuous phase map. They can be implemented computationally efficiently and are robust to noise. However, they are prone to failure in the presence of phase residues or erroneous unwraps of single tiles. We tried to overcome these shortcomings by creating novel tile unwrapping and merging algorithms as well as creating a framework that allows to combine them in modular fashion. To increase the robustness of the tile unwrapping step, we implemented a model-based algorithm that makes efficient use of linear algebra to unwrap individual tiles. Furthermore, we adapted an established pixel-based unwrapping algorithm to create a quality guided tile merger. These original algorithms as well as previously existing ones were implemented in a modular phase unwrapping C++ framework. By examining different combinations of unwrapping and merging algorithms we compared our method to existing approaches. We could show that the appropriate choice of unwrapping and merging algorithms can significantly improve the unwrapped result in the presence of phase residues and noise. Beyond that, our modular framework allows for efficient design and test of new tile-based phase unwrapping algorithms. The software developed in this study is freely available.

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3D left ventricular strain by phase unwrapping: A simulated annealing based branch-cut placement method

Cited by 2 publications

References 8 publications

Phase quality map based on local multi-unwrapped results for two-dimensional phase unwrapping

Phase quality map based on local multi-unwrapped results for two-dimensional phase unwrapping

Tile-Based Two-Dimensional Phase Unwrapping for Digital Holography Using a Modular Framework

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