基于数字体图像相关方法的椎骨内部变形无损检测研究

Research on nondestructive testing for internal deformation in vertebra has medicinal value and academic significance. In existing test methods, digital volume correlation (DVC) is an ideal nondestructive method which can quantify the full deformation in the interior of vertebra. But DVC is faced with some difficulties, such as imperfect experimental technique and algorithm, low precision and calculation efficiency. In this project, these problems will be researched. Firstly, based on a series of comparison experiment, DVC method will be researched for test internal deformation in the whole vertebra through micro-CT. Secondly, image preprocessing method will be studied and algorithm of DVC will be improved to fit medical CT. A new nondestructive testing method for internal deformation in vertebra will be obtained, which is based on DVC and medical CT. The precision and accuracy of new method can meet the requirement for practical applications. After that, algorithm will be optimized to enhance the calculation efficiency. The calculation program will be compiled through right computing technology. At last, according suitable experimental equipment and procedure of testing, internal deformation in vertebra during the simulative treatment will be tested. The biomechanical model of vertebra will be created. This research can bring a useful experimental means for mechanical behavior of bone. The results can provide scientific basis for therapeutic scheme optimization. And the research can provide reference for nondestructive testing of internal deformation in similar materials. It has scientific significance and broad application value.

椎骨内部变形的无损检测研究，具有重要的医学价值和学术意义。在现有的检测方法中，数字体图像相关法（DVC）是较为理想的椎骨内部变形无损检测技术，但仍存在实验技术和算法不完善，测量精度和计算效率低等困难。项目拟针对以上问题开展研究：首先，通过多组对比实验，建立基于显微CT，适合完整椎骨内部变形检测的DVC方法。其次，针对医用CT的特点，研究合适的图像预处理方法，完善DVC算法，建立基于DVC方法和医用CT的椎骨内部变形无损检测技术，其测量精度和准确度等满足实际检测要求。然后，进一步优化算法和采用合适的计算技术，以提升计算效率，并编写计算软件。最后，设计合适的实验装置和检测步骤，实际检测椎骨标本在模拟治疗过程中的内部变形，建立椎骨生物力学模型。研究成果可为探讨骨力学行为提供有力的实验手段，为优化治疗方案提供科学依据，并为具有相似结构材料的内部变形检测提供借鉴，具有重要的研究价值和广阔的应用前景。

脊柱侧凸矫正的实质是脊柱系统受到外力作用使其强制变形，恢复到正常形态的过程，是一种典型的力学问题。椎骨作为脊柱的主要承力结构，无损精确测量椎骨组织内部变形信息有利于医学诊断和优化治疗方案。现有的无损检测方法中，数字体图像相关方法（DVC）是较为理想的椎骨内部变形无损检测技术，但仍存在实验技术和算法不完善，测量精度和计算效率低等困难。针对该技术存在的问题，本项目首先提出了一种改进的数字体图像相关方法，通过散斑图平移实验、旋转实验、压缩试验，并与其它方法对比分析，证明了该方法在保持位移测量精度的同时显著提高了计算效率。其次，为了研究不同椎骨类型对数字体图像相关方法的影响，项目进行了四种不同椎骨的零应变实验。运用改进的数字体图像相关方法计算其位移场和应变场，并分析了不同类型的椎骨其图像的平均灰度梯度、骨体积分数等因素对数字体图像相关方法测量结果的影响。项目最后将改进的DVC方法与医用CT结合测量椎骨内部变形，测得的计算结果相对误差较小且范围可控，证明了两者结合的可行性。此外，我们分析了椎骨内部变形测量的误差来源及其产生的影响，从医用CT设备和数字体图像相关方法两方面进行了探讨。本项目建立的基于医用电子计算机断层扫描设备结合DVC方法的椎骨内部变形检测系统，可为椎骨矫正治疗方案提供科学依据，具有广阔的应用前景和重要的学术价值。