Haaker P, Klotz E, Koppe R, Linde R
Philips GmbH Forschungslaboratorium Hamburg, FRG.
Int J Card Imaging. 1990;6(1):39-45. doi: 10.1007/BF01798431.
In X-ray image intensifier (II)/TV-camera systems geometric distortions occur, e.g. due to the curved input screen of the II. For methods which are based on a pixelwise comparison of images, e.g. digital angio-tomosynthesis, an accurate correction of these geometric distortions is absolutely necessary. For the application of tomosynthesis to coronary angiography the correction in addition has to be done in real-time, because the reconstruction of the three dimensional structure of the blood vessels has to be done while the patient is undergoing catheterization. This paper describes a digital correction unit which allows a large variety of geometric distortions to be corrected. It consists of an input memory for storing the distorted image, an output memory for storing the corrected image and a special address memory which will serve as an address table during the correction step. For each element of the output image the location of the corresponding element of the distorted input image is determined in a preprocessing step and stored in the address memory. The actual correction of an image is then done while the image is copied from the input into the output memory. In this way 512 x 512 images can be corrected in real-time by a 32-bit 680X0-based microprocessor system. Presented as Poster at the 3rd International Symposium CAR '89 Computer Assisted Radiology, Berlin, June 25-28, 1989.
在X射线影像增强器（II）/电视摄像机系统中会出现几何失真，例如由于影像增强器的弯曲输入屏导致的失真。对于基于图像逐像素比较的方法，例如数字血管断层合成，精确校正这些几何失真是绝对必要的。对于将断层合成应用于冠状动脉造影，校正还必须实时进行，因为血管三维结构的重建必须在患者进行导管插入术时完成。本文描述了一种数字校正单元，它可以校正多种几何失真。它由一个用于存储失真图像的输入存储器、一个用于存储校正后图像的输出存储器以及一个特殊的地址存储器组成，该地址存储器在校正步骤中将用作地址表。对于输出图像的每个元素，在预处理步骤中确定失真输入图像中相应元素的位置，并存储在地址存储器中。然后在将图像从输入复制到输出存储器时对图像进行实际校正。通过基于32位680X0的微处理器系统，可以实时校正512×512的图像。于1989年6月25日至28日在柏林举行的第三届国际CAR '89计算机辅助放射学研讨会上以海报形式展示。
