以镜头光圈分类 镜头有手动光圈（manual iris）和自动光圈（auto iris）之分，配合摄象机使用，手动光圈镜头适合于亮度不变的应用场合，自动光圈镜头因亮度变更时其光圈亦作自动调整，故适用亮度变化的场合。-This paper describes an end-to-end method for extracting

moving targets from a real-time video stream, classifying

them into predefined categories according to imagebased

properties, and then robustly tracking them. Moving

targets are detected using the pixel wise difference between

consecutive image frames. A classification metric is applied

these targets with a temporal consistency constraint

to classify them into three categories: human, vehicle or

background clutter. Once classified, targets are tracked by

a combinationof temporal differencing and templatematching.