【摘要】 经典的CT重建算法基于X射线源为单色源的假设,而实际上由于工业CT机或医用CT机的X射线是多色的,通常只能得到多色投影数据。若直接用多色投影数据来重建图像,就会出现射束硬化伪迹,这种硬化伪迹如果不校正就会影响医学诊断和工业检测的结果。本文通过对计算机断层成像中射束硬化产生的原因分析,给出了基于单成分被测物体的射束硬化校正算法,并对算法进行了数值模拟。更多还原

【Abstract】 Classical reconstruction algorithms assume that the X-ray is monochromatic while in fact X-ray is polychromatic either in industrial or in medical CT.So only polychromatic projection data have been obtained in actual CT system.Once this kind of data is used to reconstruct the image directly,beam-hardening artifacts appear in the reconstructed image.In order to eliminate the beam-hardening artifacts,most current correction algorithms have to assume that the X-ray beam spectra are known and the mass attenuation coefficients of the detected object related to different energy are given.However,the beam spectrum of a CT system is not constant normally.By analyzing the cause of the beam-hardening artifacts in Computed Tomography,an algorithm of beam-hardening correction for single material object was proposed with results of numerical simulation.更多还原