具有全局平移优先属性的主动轮廓更适于目标跟踪。演化轮廓具有的全局平移优先性可以理解为沿轮廓的速度场具有相等的倾向。根据此思想，通过定义在曲线扰动集合上的新内积空间导出了一种简单，具有平移优先的梯度流。新的内积空间由于是通过向〖WTHX〗H〖WTBZ〗0主动轮廓对应的內积空间引入曲线扰动的方差获得，所以此主动轮廓称为方差主动轮廓。方差主动轮廓是将〖WTHX〗H〖WTBZ〗0主动轮廓与其对应的平均梯度流通过加权求和获得，而〖WTHX〗H〖WTBZ〗1主动轮廓则是通过〖WTHX〗H〖WTBZ〗0主动轮廓与特定类型的核函数进行卷积得到。因此方差主动轮廓实现时更简单和快速。最后给出了〖WTHX〗H〖WTBZ〗0，〖WTHX〗H〖WTBZ〗1和方差主动轮廓在频域与时域的分析。

Global translation preferred active contour is much more suitable for object tracking. The prior information of active contour with global translation preference can be interpreted as the velocity field along the evolving contour with equivalency preference. According to this, a simple gradient flow which preferes global translation is acquired by defining a new inner product on the set of perturbations of a curve. The new inner product is obtained by adding the variance of the perturbation of a curve to the inner product relative to the 〖WTHX〗H〖WTBZ〗0 active contour. The active contour relative to the new inner product is called variance active contour. In contrast to 〖WTHX〗H〖WTBZ〗1 active contour generated by convolution of 〖WTHX〗H〖WTBZ〗0 active contour and certain kernel functional, variance active contour needs no convolution and is a weighting sum of 〖WTHX〗H〖WTBZ〗0 active contour and corresponding average gradient flow. Thus, variance active contour can be implemented much faster and easier than 〖WTHX〗H〖WTBZ〗1 active contour. We also compared 〖WTHX〗H〖WTBZ〗0, 〖WTHX〗H〖WTBZ〗1 and variance active contours in space and frequency domains.