Large field-depth iris image capturing system and method based on multiple cameras with fixed focus

An iris image and image acquisition technology, applied in the direction of instruments, character and pattern recognition, computer components, etc., can solve the problems of limited stability and service life, difficult iris recognition real-time requirements, slow zoom speed, etc., to achieve convenient signal processing, easy to fit segmentation and normalization, and fast focusing

Active Publication Date: 2008-04-02
INST OF AUTOMATION CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0010] The prior art iris recognition system using an automatic zoom lens has problems such as high cost, slow zoom speed, difficulty in meeting the real-time requirements of iris recognition, zoom noise, limited stability and service life, etc. In order to solve the problems of the prior art, The purpose of the present invention is to propose to use the complementarity of different fixed-focus cameras to expand the depth of field and the effective imaging range of iris image acquisition to achieve the effect of automatic zooming. For this reason, the present invention provides a large depth-of-field based on multiple fixed-focus cameras. Iris image acquisition system and method

Method used

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  • Large field-depth iris image capturing system and method based on multiple cameras with fixed focus
  • Large field-depth iris image capturing system and method based on multiple cameras with fixed focus

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example 1

[0077] As shown in Fig. 3, the same focal length camera schematic diagram installed in different depth positions in the present invention:

[0078] Two identical fixed-focus cameras 4 are used, assuming that their imaging range is 20-30 cm. These cameras 4 are installed at different depth positions, and when their distance d is 10 centimeters, the overall imaging object distance range of the iris acquisition device 2 is 10 to 30 centimeters, and the overall effective imaging range of the system of the present invention is enlarged. Double (from 10 cm to 20 cm).

example 2

[0080] As shown in Fig. 4 fixed-focus cameras of different focal lengths in the present invention, the same iris is imaged by a beam splitter as shown in the structural diagram, and the symbols in the figure are represented as:

[0081] Iris 1 is eyes, beam splitter 9, fixed-focus camera 41 and fixed-focus camera 42 of different depths of field, wherein:

[0082] The fixed-focus camera 41 and the fixed-focus camera 42 adopt two completely different fixed-focus cameras, assuming that their imaging ranges are 10-20 cm and 20-30 cm respectively. Through the beam splitter 9, or half through the half-reflection film Beam Splitter, the reflected light of the monocular iris 1 is distributed to different fixed-focus camera imaging 41 and fixed-focus camera imaging 42, wherein half of the light enters the camera 42 by reflection, and the other half of the light Enter the camera 41 through the beam splitter. In this way, the overall imaging object distance range of the iris acquisition...

example 3

[0084] As shown in Figure 5, the fixed-focus cameras of different focal lengths in the present invention are shown in a structural schematic diagram of different irises respectively:

[0085] When multiple fixed-focus cameras 4 have different focusing distances, these cameras 4 can be installed at the same depth position, and different imaging object distance ranges can also be realized.

[0086] Two completely different fixed-focus cameras 41 and 42 are selected, assuming that their imaging ranges are 10-20 cm and 15-25 cm respectively. These cameras 41 and fixed-focus cameras 42 are installed at the same depth position to image the iris 1 , that is, the left eye 11 and the right eye 12 respectively.

[0087] When the distance between the left eye 11 and the right eye 12 and the fixed-focus camera 41 and the fixed-focus camera 42 is in the range of 10 to 15 centimeters, the system of the present invention outputs the iris image of the left eye 11 for identification.

[0088]...

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Abstract

The invention which relates to an optical instrument and detection imaging technique discloses a large field depth iris image acquisition system and a method based on a plurality of fixed-focus cameras. The system comprises an iris image collecting device and an image recognition device. The method comprises the following steps: respectively imaging the iris by means of the fixed-focus cameras having different imaging object distance ranges and producing a multi-path fixed-focus image results; choosing one or a plurality of multi-path fixed-focus image results through distance measurement or image quality evaluation method; carrying out image processing and identification of chosen qualified iris image data. The invention effectively integrates the imaging ranges of different fixed-focus cameras in the mode of self-adapting switchover, thereby taking advantages of the cameras and at same time removing disadvantages of the cameras, enlarging the integral imaging range of the acquisition system, and improving the feasibility of an iris recognition system. Compared with the prior iris imaging method adopting a zoom camera, the invention has the advantages of low cost, quick and noiseless focusing.

Description

technical field [0001] The invention belongs to the technical field of optical instruments and detection and imaging, and in particular relates to a technology for expanding the iris imaging range by using multiple fixed-focus cameras. Background technique [0002] Safety management has become the focus of attention of the international community. Among many security protection technologies, the identification technology of access control (Access Control) to physical places and information materials is the core technology for public safety and personal family safety protection, and has a wide range of applications in various fields related to the national economy and people's livelihood. For example, units and places such as state agencies, customs, nuclear power plants, military bases, civil aviation airports, railways, bank vaults, energy and mineral resources, scientific research laboratories, archives, office buildings and production workshops of enterprises and institut...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06K9/00G06K9/20
Inventor 谭铁牛孙哲南何杰
Owner INST OF AUTOMATION CHINESE ACAD OF SCI
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