Automatic-tracking and automatic-zooming method for acquiring iris images

The invention relates to an automatic-tracking and automatic-zooming method for acquiring iris images. The method includes the following steps: a camera with wide angle of view, a camera with narrow angle of view (long focus) and an infrared light source are closely installed on a controllable tripod head which drives the two cameras and the infrared light source to rotate simultaneously; a system adopts the camera with wide angle of view to continuously detect facial images of human; when the facial image is available, eye images of human are detected to obtain the exact locations of human eyes; and then the tripod head is controlled to rotate up and down or left and right, which allows that the camera with narrow angle of view and the infrared light source aim at the human eyes; user distance and picture quality are determined simultaneously to control the camera to automatically zoom; when clear iris images are acquired, image processing and iris recognition are carried out and the user identity is determined. A system device comprises a computer, the controllable tripod head, the camera with wide angle of view, the camera with narrow angle of view, the infrared light source, a power supply, an image grabbing card and other auxiliary equipments.