Investigations of Ultrasound Propagation and Image Processing

超声波传播和图像处理的研究

• 批准号: 3297-2012
• 负责人: Cobbold, Richard
• 金额: $ 2.4万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=568283
• 关键词: Investigations; Ultrasound; Propagation; Image; Processing

Ultrasound is widely used both for medical diagnostic and therapeutics as well as for many industrial applications. Its importance for medical diagnosis arises from its non-invasive nature and its ability to provide images and quantitative information in a relatively economical manner using systems that are not much larger than a lap-top computer. Diagnostic systems make use of transducers that emit the ultrasound and gather the reflected signal so as to create structural images or to image blood flow. They have a number of limitations which, with the help of new ideas and improvements in signal and image processing, should enable their performance to be further enhanced. In this grant application several sub-topics are proposed, some of which address current limitations and some consider issues directly related to diagnostic applications. In what follows below, just two of the topics are detailed. The complexity of US diagnostic systems and the wide variety of abnormalities that are present in the patients being examined make it important to develop simulation systems for training radiologists and sonographers, much like that used for real-time airline pilot training. Up to now a major problem has been the difficulty of simulating the transducer field properties in real-time. Recently, we have shown how this can be addressed as a parallelizable problem rather than as an impulse response. We will further develop this idea. The second topic that we plan to further investigate is the use of phononic metamaterials (a class of engineered materials) for achieving sharper ultrasound images with a greater depth of field, and possibly, sub-wavelength resolution. Such materials have two or more constituent materials arranged in a periodic manner. Acoustic wave propagation in such a medium can exhibit negative refraction, enabling unique field manipulation properties to be developed. Compressional and shear waves may be present with wave-mode conversion occurring at the interfaces. To better understand wave propagation we are developing new methods for analyzing such media with the expectation that this could lead to improved imaging systems.

超声被广泛用于医学诊断和治疗以及许多工业应用。其对于医学诊断的重要性源于其非侵入性性质以及其使用不比膝上型计算机大得多的系统以相对经济的方式提供图像和定量信息的能力。诊断系统利用发射超声并收集反射信号的换能器，以便创建结构图像或对血流进行成像。它们有一些局限性，在信号和图像处理方面的新想法和改进的帮助下，应能使它们的性能得到进一步提高。在这个补助金申请提出了几个子课题，其中一些解决当前的限制和一些考虑的问题直接相关的诊断应用。在下面的内容中，仅详细介绍其中两个主题。 US诊断系统的复杂性和被检查的患者中存在的各种各样的异常使得开发用于培训放射科医生和超声检查员的模拟系统非常重要，就像用于实时航空公司飞行员培训的模拟系统一样。到目前为止，一个主要的问题一直是难以实时模拟换能器场特性。最近，我们已经展示了如何将其作为可并行化的问题而不是脉冲响应来解决。我们将进一步发展这一想法。 我们计划进一步研究的第二个主题是使用声子超材料（一类工程材料）实现更清晰的超声图像，具有更大的景深，可能还有亚波长分辨率。这种材料具有以周期性方式布置的两种或更多种构成材料。声波在这种介质中的传播可以表现出负折射，从而能够开发出独特的场操纵特性。 压缩波和剪切波可能存在，在界面处发生波模转换。 为了更好地理解波的传播，我们正在开发新的方法来分析这种介质，期望这可以导致改进的成像系统。