Zoom iris recognition lens

Abstract

The invention discloses a zoom iris recognition lens, and belongs to the field of biological recognition. The zoom iris recognition lens sequentially comprises a first lens group, a second lens group,a third lens group, a diaphragm and a fourth lens group from an object side to an image side, wherein the first lens group is a front fixed group with positive focal power; the second lens group is azoom group with negative focal power; the third lens group is a compensation group with positive focal power; and the fourth lens group is rear fixed groups with positive focal power. The positions of the front fixed group and the rear fixed group are relatively fixed, zooming is achieved through movement of a zooming group along an optical axis, image surface drifting caused by movement of the zooming group is compensated through movement of a compensation group along the optical axis, and the image surface is ensured to be kept unchanged in the whole zooming process, which means that the total optical length of the lens is kept unchanged. According to the zoom iris recognition lens, the iris acquisition flexibility can be higher, and uniform zooming can be realized in a working range of210-630mm. And high-quality iris images can be acquired at each focal length in a relatively large working range.

Description

technical field [0001] The invention relates to an iris recognition lens, in particular to a zoom iris recognition lens. Background technique [0002] With the increasing application of identity recognition, traditional identity recognition can no longer meet the market demand in terms of accuracy and security. Due to the continuous improvement of technology, biometric technology is well known to the public because of its reliability and accurate identification. . Compared with common biometric technologies, the researchers found that the accuracy and anti-counterfeiting characteristics of iris recognition are particularly prominent. Therefore, iris recognition technology has become one of the focuses of research on identification technology in recent years. Among them, the collection of iris texture features is the basic step of iris recognition, and its image quality is the key to the accuracy of the entire system. Therefore, The image quality of the lens must be guarant...

AI Technical Summary

Problems solved by technology

Existing iris recognition lenses are generally fixed-focus lenses. Since the focal length of fixed-focus lenses cannot be changed, the collection range of iris images is very limited. To collect clear iris images requires a high level of cooperation from users, resulting in poor usability for iris recognition.

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