Attenuating the noises plays an essential role in the image processing. Almost all the traditional median filters concern the removal of impulse noise having a single layer, whose noise gray level value is constant. I...Attenuating the noises plays an essential role in the image processing. Almost all the traditional median filters concern the removal of impulse noise having a single layer, whose noise gray level value is constant. In this paper, a new adaptive median filter is proposed to handle those images corrupted not only by single layer noise. The adaptive threshold median filter （ATMF） has been developed by combining the adaptive median filter （AMF） and two dynamic thresholds. Because of the dynamic threshold being used, the ATMF is able to balance the removal of the multiple-impulse noise and the quality of image. Comparison of the proposed method with traditional median filters is provided. Some visual examples are given to demonstrate the performance of the proposed filter.展开更多
目的探讨和构建北京人群神经管缺陷(neural tube defect,NTD)产前筛查的血清标志物甲胎蛋白(α-fetoprotein,AFP)浓度中位数倍数(multiple of the median,MOM)的校正模型。方法选取5668例孕中期孕妇,通过分析其AFP浓度与孕周和体重之间...目的探讨和构建北京人群神经管缺陷(neural tube defect,NTD)产前筛查的血清标志物甲胎蛋白(α-fetoprotein,AFP)浓度中位数倍数(multiple of the median,MOM)的校正模型。方法选取5668例孕中期孕妇,通过分析其AFP浓度与孕周和体重之间的相关性,分别进行回归分析,根据统计量和校正决定系数选取最优模型,校正AFP。结果 35岁以下(<35y)组,分别用指数和幂回归模型进行孕周和孕妇体重的校正;35岁及以上(≥35y)组,分别用S和二次回归模型进行孕周和孕妇体重的校正。校正前,孕周与AFP MOM值呈显著正相关(<35y:r=0.412,P=0.000;≥35y:r=0.435,P=0.000),体重与AFP MOM值呈显著负相关(<35y:r=-0.232,P=0.000;≥35y:r=-0.228,P=0.000);校正后,AFPMOM值与孕周(<35y:r=0.446,P=0.911;≥35y;r=0.001,P=0.985)和体重(<35y:r=0.010,P=0.483;≥35y:r=0.008,P=0.887)均无相关性。结论基于北京人群孕中期妇女血清标志物AFP水平建立的MOM校正模型可以有效地消除孕周和体重的影响。展开更多
文摘Attenuating the noises plays an essential role in the image processing. Almost all the traditional median filters concern the removal of impulse noise having a single layer, whose noise gray level value is constant. In this paper, a new adaptive median filter is proposed to handle those images corrupted not only by single layer noise. The adaptive threshold median filter （ATMF） has been developed by combining the adaptive median filter （AMF） and two dynamic thresholds. Because of the dynamic threshold being used, the ATMF is able to balance the removal of the multiple-impulse noise and the quality of image. Comparison of the proposed method with traditional median filters is provided. Some visual examples are given to demonstrate the performance of the proposed filter.
文摘目的探讨和构建北京人群神经管缺陷(neural tube defect,NTD)产前筛查的血清标志物甲胎蛋白(α-fetoprotein,AFP)浓度中位数倍数(multiple of the median,MOM)的校正模型。方法选取5668例孕中期孕妇,通过分析其AFP浓度与孕周和体重之间的相关性,分别进行回归分析,根据统计量和校正决定系数选取最优模型,校正AFP。结果 35岁以下(<35y)组,分别用指数和幂回归模型进行孕周和孕妇体重的校正;35岁及以上(≥35y)组,分别用S和二次回归模型进行孕周和孕妇体重的校正。校正前,孕周与AFP MOM值呈显著正相关(<35y:r=0.412,P=0.000;≥35y:r=0.435,P=0.000),体重与AFP MOM值呈显著负相关(<35y:r=-0.232,P=0.000;≥35y:r=-0.228,P=0.000);校正后,AFPMOM值与孕周(<35y:r=0.446,P=0.911;≥35y;r=0.001,P=0.985)和体重(<35y:r=0.010,P=0.483;≥35y:r=0.008,P=0.887)均无相关性。结论基于北京人群孕中期妇女血清标志物AFP水平建立的MOM校正模型可以有效地消除孕周和体重的影响。
