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Two-Dimensional Flow Field Measurement Method for Sediment-Laden Flow Based on Optical Flow Algorithm. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12052720] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
This paper proposes a novel particle image velocimetry (PIV) technique to generate an instantaneous two-dimensional velocity field for sediment-laden fluid based on the optical flow algorithm of ultrasound imaging. In this paper, an ultrasonic PIV (UIV) system is constructed by integrating a medical ultrasound instrument and an ultrasonic particle image velocimetry algorithm. The medical ultrasound instrument with a phased sensor array is used to acquire acoustic echo signals of particles in water and generate two-dimensional underwater ultrasound images. Based on the optical flow field, the instantaneous velocity of the particles in water corresponding to the pixels in the ultrasonic particle images is derived from the grayscale change between adjacent images under the L-K local constraint based on the optical flow field, and finally, the two-dimensional flow field is obtained. Through multiple sets of experiments, the proposed algorithm is verified. The experimental results are compared with those of the conventional cross-correlation algorithms. The results show that the L-K optical flow method can not only obtain the underwater velocity field accurately, but also has the advantages of good smoothness and extensive suitability, especially for the flow field measurement in sediment-laden fluid than conventional algorithms.
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Yang JM, Ghim CM. Photoacoustic Tomography Opening New Paradigms in Biomedical Imaging. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1310:239-341. [PMID: 33834440 DOI: 10.1007/978-981-33-6064-8_11] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
After the emergence of the ultrasound, X-ray CT, PET, and MRI, photoacoustic tomography (PAT) is now in the phase of its exponential growth, with its expected full maturation being another form of mainstream clinical imaging modality. By combining the high contrast benefit of optical imaging and the high-resolution deep imaging capability of ultrasound, PAT can provide unprecedented anatomical image contrasts at clinically relevant depths as well as enable the use of a variety of functional and molecular imaging information, which is not possible with conventional imaging modalities. With these strengths, PAT has achieved numerous breakthroughs in various biomedical applications and also provided new technical platforms that may be able to resolve unmet issues in clinics. In this chapter, we provide an overview of the development of PAT technology for several major biomedical applications and provide an approximate projection of the future of PAT.
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Affiliation(s)
- Joon-Mo Yang
- Center for Photoacoustic Medical Instruments, Department of Biomedical Engineering, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea.
| | - Cheol-Min Ghim
- Department of Physics, School of Natural Science, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea
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Ravina K, Lin L, Liu CY, Thomas D, Hasson D, Wang LV, Russin JJ. Prospects of Photo- and Thermoacoustic Imaging in Neurosurgery. Neurosurgery 2020; 87:11-24. [PMID: 31620798 DOI: 10.1093/neuros/nyz420] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 07/25/2019] [Indexed: 12/25/2022] Open
Abstract
The evolution of neurosurgery has been, and continues to be, closely associated with innovations in technology. Modern neurosurgery is wed to imaging technology and the future promises even more dependence on anatomic and, perhaps more importantly, functional imaging. The photoacoustic phenomenon was described nearly 140 yr ago; however, biomedical applications for this technology have only recently received significant attention. Light-based photoacoustic and microwave-based thermoacoustic technologies represent novel biomedical imaging modalities with broad application potential within and beyond neurosurgery. These technologies offer excellent imaging resolution while generally considered safer, more portable, versatile, and convenient than current imaging technologies. In this review, we summarize the current state of knowledge regarding photoacoustic and thermoacoustic imaging and their potential impact on the field of neurosurgery.
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Affiliation(s)
- Kristine Ravina
- Neurorestoration Center, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Li Lin
- Caltech Optical Imaging Laboratory, Andrew and Peggy Cherng Department of Medical Engineering, Department of Electrical Engineering, California Institute of Technology, Pasadena, California.,Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri
| | - Charles Y Liu
- Neurorestoration Center, Keck School of Medicine, University of Southern California, Los Angeles, California.,Department of Neurological Surgery, Keck School of Medicine, University of Southern California, Los Angeles, California.,Department of Biology and Biological Engineering, California Institute of Technology, Pasadena, California.,Tianqiao and Chrissy Chen Brain-machine Interface Center, California Institute of Technology, Pasadena, California
| | - Debi Thomas
- Department of Surgery, University of California Davis, Davis, California
| | - Denise Hasson
- Division of Critical Care Medicine, Cincinnati Children's Hospital, Cincinnati, Ohio
| | - Lihong V Wang
- Caltech Optical Imaging Laboratory, Andrew and Peggy Cherng Department of Medical Engineering, Department of Electrical Engineering, California Institute of Technology, Pasadena, California
| | - Jonathan J Russin
- Neurorestoration Center, Keck School of Medicine, University of Southern California, Los Angeles, California.,Department of Neurological Surgery, Keck School of Medicine, University of Southern California, Los Angeles, California
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