Extending the imaging volume for biometric iris recognition

Narayanswamy, Ramkumar; Johnson, Gregory E.; Silveira, Paulo E. X.; Wach, Hans B.

doi:10.1364/ao.44.000701

Cited by 70 publications

(30 citation statements)

References 8 publications

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“…Honeywell Technologies registered a patent [3] of a similar system capable of performing at-adistance iris recognition. Previously, Fancourt et al [4] showed that it is possible to acquire images at-a-distance of up to 10 meters with sufficient quality to support iris recognition and Narayanswamy and Silveira [5] increased the iris image depthof-field through a simple framework composed by a camera with fixed focus, without a zoom lenses. Park and Kim [21] proposed an approach to fast at-a-distance acquisition of iris images and He et al [6] studied the acquisition of in-focus images, as well analyzed the impact of different wavelengths in the recognition error rates.…”

Section: A Less Constrained Image Acquisitionmentioning

confidence: 99%

On the Role of Interpolation in the Normalization of Non-ideal Visible Wavelength Iris Images

Santos

Proença

2009

2009 International Conference on Computational Intelligence and Security

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Abstract-The growth in practical applications for iris biometrics has been accompanied by relevant developments in the underlying algorithms and techniques. Along with the research focused on near-infrared (NIR) cooperatively captured images, efforts are being made to minimize the trade-off between the quality of the captured data and the recognition accuracy on less constrained environments, where images are obtained at the visible wavelength, at increased distances, over simplified protocols and adverse lightning. This paper addresses the effect of the interpolation method, used in the iris normalization stage, in the overall recognition error rates. This effect is stressed for systems operating under less constrained image acquisition setups and protocols, due to higher variations in the amounts of captured data. Our experiments led us to conclude that the utility of the image interpolating methods is directly corresponding to the levels of noise that images contain.

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Section: A Less Constrained Image Acquisitionmentioning

confidence: 99%

On the Role of Interpolation in the Normalization of Non-ideal Visible Wavelength Iris Images

Santos

Proença

2009

2009 International Conference on Computational Intelligence and Security

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“…[5][6][7][8][9][10][11][12][13][14][15][16] Nevertheless, it has been shown that cubic and trefoil-shaped phases are most used to achieve high-quality images when spherical aberration, 10,11) astigmatism 14,15) and high orderaberrations 15) are also present in the system. WFC can be found in many different applications such as in ophthalmic optics, [15][16][17] iris recognition, 18,19) complexity reduction in optical systems, 20) control of thermal defocus in infrared systems, 21) barcode reading, 22) and microscopy, 23) among many others. The DOF in each application can be extended by a trefoil phase at the exit pupil of the optical system, and the trade-off between the DOF and the image resolution properties is dependent on the peak-to-valley value (strength) of the phase.…”

Section: Introductionmentioning

confidence: 99%

Effect of spherical aberration in trefoil phase plates on color wavefront coding

Olvera-Angeles

Padilla-Vivanco

Sasián

et al. 2018

Jpn. J. Appl. Phys.

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Wavefront coding is a technique that makes use of aspheric phase masks and image processing to greatly increase the depth of focus and/or reduce the cost of imaging systems. The phase mask adds a controlled amount of aberrations to the optical system in such a way that invariant imaging properties are achieved over a wide range of defocus. When aspheric phase plates are fabricated, their shape has to be carefully designed to avoid introducing other aberrations into the optical system, which could reduce its performance. In this work, we will show how inherent spherical aberration for trefoil-shaped phase plates reduces the quality of color images. Results will be illustrated with numerical simulations. We will show that a fourth-order polynomial added to a trefoil shaped phase mask can avoid the plate generating undesired spherical aberration that will affect the final quality of the decoded color images.

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“…Many applications may benefit from extended DOF capabilities in macroscopic imaging, for example in surveillance, machine vision or biometrics problems where the DOF extension is a clear advantage [2,3]; but the technique can also be used to reduce system complexity [4] or for athermalisation and achromatisation of infrared imaging systems [5].…”

Section: Introductionmentioning

confidence: 99%

Design and implementation of a scene-dependent dynamically selfadaptable wavefront coding imaging system

Carles

Ferran

Carnicer

et al. 2012

Computer Physics Communications

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A computational imaging system based on wavefront coding is presented. Wavefront coding provides an extension of the depth-of-field at the expense of a slight reduction of image quality. This trade-off results from the amount of coding used. By using spatial light modulators, a flexible coding is achieved which permits it to be increased or decreased as needed. In this paper a computational method is proposed for evaluating the output of a wavefront coding imaging system equipped with a spatial light modulator, with the aim of thus making it possible to implement the most suitable coding strength for a given scene. This is achieved in an unsupervised manner, thus the whole system acts as a dynamically selfadaptable imaging system. The program presented here controls the spatial light modulator and the camera, and also processes the images in a synchronised way in order to implement the dynamic system in real time. A prototype of the system was implemented in the laboratory and illustrative examples of the performance are reported in this paper. The program implements an enhanced wavefront coding imaging system able to adapt the degree of coding to the requirements of a specific scene. The program controls the acquisition by a camera, the display of a spatial light modulator and the image processing operations synchronously. The spatial light modulator is used to implement the phase mask with flexibility given the trade-off between depth-of-field extension and image quality achieved. The action of the program is to evaluate the depth-of-field requirements of the specific scene and subsequently control the codifing established by the spatial light modulator, in real time.

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Extending the imaging volume for biometric iris recognition

Cited by 70 publications

References 8 publications

On the Role of Interpolation in the Normalization of Non-ideal Visible Wavelength Iris Images

On the Role of Interpolation in the Normalization of Non-ideal Visible Wavelength Iris Images

Effect of spherical aberration in trefoil phase plates on color wavefront coding

Design and implementation of a scene-dependent dynamically selfadaptable wavefront coding imaging system

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