求翻译：在通常的情况下，虹膜和瞳孔并不是严格的同心圆，但是在一般情况它们的圆心非常的接近，所以近似按照圆心相同来处理，可以通过定位虹膜的中心来找到瞳孔中心。是什么意思？

In the usual case, not strictly concentric circles of the iris and the pupil, but in general the center of a circle of very close, so the approximation in accordance with the same center of the circle, can be found by positioning the center of the iris to the pupil center.

In general, iris and pupil is not strictly a concentric circles, but in general they are very close to the center, in accordance with the approximate same circle that can be positioned by the IRIS center to find the pupil center.

正在翻译，请等待...

In the usual case, Iris and pupil is not strictly concentric, but in general they circle is very close, so similar in a circle the same treatment, can be found by locating the IRIS Center for pupil Center.

In the usual situation, the iris and the pupil are not the strict concentric circles, but in ordinary circumstances their center of circle unusual proximity, therefore is approximate same according to the center of circle processes, may through locate the iris the center to find the pupil center.