subtraction of image

基本解释

The quality of the subtraction image is improved by the multi exposure.
采用多次曝光技术，提高了相减象的质量。
The quality of the subtraction image was improved and computation time was reduced by selecting edge pixels as triangular control points.
通过计算图像梯度信息，选取边缘区域像素作为控制点，既改善减影图像质量，又提高运算速度。
Purpose: To evaluate the diagnostic value of subtraction image from ictal and interictal brain perfusion SPECT images in localization of epileptic foci.
目的：研究癫痫发作期与发作间期脑血流灌注显像减影法定位致癫灶的价值。