中文摘要：

提出了一种基于逆拉伸空间变换的蒙片像素点灰度值映射求解方法。实验中使蒙片网格化以产生恰当的控制点，采用最大减影直方图能量相似性测度准则和鲍威尔优化搜索方法，对蒙片图像和活片图像进行局部变形非刚性配准。该算法有效保证了蒙片图像变形前后灰度值变化的拓扑一致，使变形后的蒙片图像仍保持清晰准确的轮廓，配准后的减影图像质量良好，噪声和伪影明显减少，同时省去插值计算过程，配准速度明显提高，为临床中的脑血管病变诊断提供了有力支持。

英文摘要：

In order to reduce the resulting artifacts after subtraction operation in Digital Subtraction Angiography（DSA）, this paper presents an algorithm for spatial transformation based on inverse stretching. It is a new method of gray scale mapping for Mask Image. In the experiment the Mask Image was plotted into rectangular blocks of 32 × 32 pixds to build control points. Energy of Histogram of Differences （EHD） method was selected as comparability estimate. Powell optimization strategy was used to search the optimal matching points. The Mask Image and Live Image were non-rigidly registered after the experiment. This algorithm effectively ensures the topology of gray scale variety consistent before and after the distortion for the Mask Image. The Mask Image keeps a dear and exact contour all along. The subtraction images after registration are of high quality, and the noise and artifacts lessen visibly. This registration method dispense with interpolation process. So the speed of registration advances obviously. It provides tremendous support for the diagnosis of cerebral vas pathological changes.