摘要
本文讨论一种带有噪声检测功能的QRS检测器,能检测用一般滤波器难于去除的跃变干扰和肌电干扰,并将它们对QRS检测的影响减至最小。跃变干扰是由电极脱落或移动产生的,它的检测是用相当于高通滤波器的噪声放大器来实现的;肌电干扰是通过对原始数据中满足阈值的峰谷点进行标记,并用一维腐蚀和膨胀运算对标记群处理得到检测结果的。文中还讨论一个新的二级QRS检测函数,第一次检测函数是由一种特性类似长度变换但速度快近10倍的非线性变换得到的,已检出的噪声控制这一变换以减小噪声对QRS检测的影响;第二级QRS检测函数由改进的零面积对称变换得到,目的是去除由于噪声影响在第一次检测函数中变高的本底,进一步降低假阳性率,用34个半小时的数据进行测试,QRS检出率达99.85％,假阳性率小于0.70％,假阴性率小于0.20％,对QRS检测影响较大的噪声的检出率达90％以上。
A new QRS detection techniqne combined with a noise detector has been investigated. The noise detector detects spikes and EMG artifacts, which are difficult to be removed by normal filters, in order to minimize their influence on QRS detection. The irregular tremendous spikes are caused by loss of contact between the electrode and skin and their detection is based on a noise amplifier, that serves as a highpass filter. Algorithms of one-dimensional erosion and dilation have been used to detect EMG artifacts. The QRS detector has two detection functions. The first function is a new nonlinear transformation similar to length transformation but ten times faster. The marks of detected noises control the transformation to reduce the noise influence. The second function, which is a modified zero-area symmetry transformation, is used to remove the high background in the first function caused by noise and minimize the false positives The technique is tested with 34 half-hour records of patient data. QRS sensitivity of 99.85 percent with false positive of 0.70 percent have been achieved. About 90 percent of the noises having heavy influence on QRS detection have been detected.
出处
《中国医疗器械杂志》
CAS
1993年第1期1-6,共6页
Chinese Journal of Medical Instrumentation
