Nonintrusive iris image acquisition system based on a pan-tilt-zoom camera and light stripe projection

Yoon, Soweon; Jung, Ho Gi; Park, Kang Ryoung; Kim, Jai Hie

doi:10.1117/1.3095905

Cited by 11 publications

(12 citation statements)

References 14 publications

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“…21 Yoon et al 21 used a wide-view camera with a costly light plane projector to find the X, Y, and Z positions of subject's legs, and a narrow-view megapixel camera with a panning and tilting mechanism captures a face image in which a high-resolution iris image can be obtained. 21 Yoon et al 21 used a wide-view camera with a costly light plane projector to find the X, Y, and Z positions of subject's legs, and a narrow-view megapixel camera with a panning and tilting mechanism captures a face image in which a high-resolution iris image can be obtained.…”

Section: Introductionmentioning

confidence: 99%

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Auto-focusing method for remote gaze tracking camera

Lee

Cho

et al. 2012

Opt. Eng

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Gaze tracking determines what a user is looking at; the key challenge is to obtain well-focused eye images. This is not easy because the human eye is very small, whereas the required resolution of the image should be large enough for accurate detection of the pupil center. In addition, capturing a user's eye image by a remote gaze tracking system within a large working volume at a long Z distance requires a panning/tilting mechanism with a zoom lens, which makes it more difficult to acquire focused eye images. To solve this problem, a new auto-focusing method for remote gaze tracking is proposed. The proposed approach is novel in the following four ways: First, it is the first research on an auto-focusing method for a remote gaze tracking system. Second by using userdependent calibration at initial stage, the weakness of the previous methods that use facial width in captured image to estimate Z distance between a user and camera, wherein each person has the individual variation of facial width, is solved. Third, the parameters of the modeled formula for estimating the Z distance are adaptively updated using the least squares regression method. Therefore, the focus becomes more accurate over time. Fourth, the relationship between the parameters and the face width is fitted locally according to the Z distance instead of by global fitting, which can enhance the accuracy of Z distance estimation. The results of an experiment with 10,000 images of 10 persons showed that the mean absolute error between the ground-truth Z distance measured by a Polhemus Patriot device and that estimated by the proposed method was 4.84 cm. A total of 95.61% of the images obtained by the proposed method were focused and could be used for gaze detection.

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Section: Introductionmentioning

confidence: 99%

“…21) Information from both additional sensors and additional cameras is used. 21) Information from both additional sensors and additional cameras is used.…”

Section: Introductionmentioning

confidence: 99%

Auto-focusing method for remote gaze tracking camera

Lee

Cho

et al. 2012

Opt. Eng

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“…These can be divided into two categories: 2 portal-based systems [4][5][6] and pan-tilt-zoom (PTZ)-based systems. [7][8][9][10][11][12][13] The portal-based system looks like a metal detector used by airport security, on which several high resolution mega-pixel cameras are installed. When a person passes through the portal at a normal walking speed, the cameras capture the assigned area, and one of them tries to acquire a good-quality iris image.…”

Section: Introductionmentioning

confidence: 99%

“…The camera on the PTU is called an iris camera and the additional camera is called a scene camera. 7 When a user stands within the capture volume, the system directs the iris camera to the user's eye using the PTU, and captures a high-resolution iris image using a zoom lens. This system mainly aims at improving the user's convenience by providing a relatively large capture volume.…”

Section: Introductionmentioning

confidence: 99%

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Coaxial optical structure for iris recognition from a distance

2011

Opt. Eng

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Supporting an unconstrained user interface is an important issue in iris recognition. Various methods try to remove the constraint of the iris being placed close to the camera, including portal-based and pan-tiltzoom (PTZ)-based solutions. Generally speaking, a PTZ-based system has two cameras: one scene camera and one iris camera. The scene camera detects the eye's location and passes this information to the iris camera. The iris camera captures a high-resolution image of the person's iris. Existing PTZ-based systems are divided into separate types and parallel types, according to how the scene camera and iris camera combine. This paper proposes a novel PTZ-based iris recognition system, in which the iris camera and the scene camera are combined in a coaxial optical structure. The two cameras are placed together orthogonally and a cold mirror is inserted between them, such that the optical axes of the two cameras become coincident. Due to the coaxial optical structure, the proposed system does not need the optical axis displacement-related compensation required in parallel-type systems. Experimental results show that the coaxial type can acquire an iris image more quickly and accurately than a parallel type when the stand-off distance is between 1.0 and 1.5 m. C 2011 Society of Photo-Optical Instrumentation Engineers (SPIE).

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