物理模型超声CT图像代数法重建和结构识别

本文采用木板、有机玻璃板制作二维物理模型，并在模型中加入三个大小不一、位置各异、用石膏充填的方洞。对两个物理模型布置相同的观测系统，形成相同的射线方式，在等间距矩形像素条件下，每条射线的积分步长（射线穿过单个像素的射线段长度）皆为常数。由超声仪器沿指定射线采集各条透射波射线的走时数据（即Radon变换线积分的“观测值”）。应用“代数重建法”（ART加法修正迭代法）求解Radon变换的离散化方程组，重建二维物理模型的CT数字图像。在重建的模型CT数字图像中，能够有效地识别出“石膏洞”的存在和位置，验证了“代数重建法”CT成像技术及其对模型结构识别的有效性。本文是ART加法修正迭代的基础性应用工作，可为有关部门提供“代数重建法”CT成像实际应用参考。

Algebraic Reconstruction and Structure Recognition for Ultrasound CT Image on Physical Model

In this paper, a two-dimensional physical model made of "wood board" and "plexiglass board" is adopted, and three square holes of different sizes and positions, filled with gypsum are added to the model. The same observation system is arranged for the two physical models to form the same ray mode. Under the condition of equally spaced rectangular pixels, the integration step size of each ray (the length of the ray segment passing through a single pixel) is a constant. The travel time data of each transmitted wave ray (i.e. the "observed value" of the Radon transform line integral) is collected by the ultrasonic instrument along the designated ray. The "algebraic reconstruction method" (ART addition modified iteration method) is used to solve the discretized equations of the Radon transform, and the CT digital image of the two-dimensional physical model is reconstructed. In the reconstructed model CT digital image, the existence and location of "gypsum hole" can be effectively identified, which verifies the effectiveness of "algebraic reconstruction" CT imaging technology and its recognition of model structure. This paper is basic research of addition modified iteration ART and provides practical application reference for those who interest in" Algebraic Reconstruction Technique".