Kazuyuki Miyazawa

An Effective Approach for Iris Recognition Using Phase-Based Image Matching

This paper presents an efficient algorithm for iris recognition using phase-based image matching - an image matching technique using phase components in 2D discrete Fourier transforms (DFTs) of given images. Experimental evaluation using the CASIA iris image databases (versions 1.0 and 2.0) and Iris challenge evaluation (ICE) 2005 database clearly demonstrates that the use of phase components of iris images makes it possible to achieve highly accurate iris recognition with a simple matching algorithm. This paper also discusses the major implementation issues of our algorithm. In order to reduce the size of iris data and to prevent the visibility of iris images, we introduce the idea of 2D Fourier phase code (FPC) for representing iris information. The 2D FPC is particularly useful for implementing compact iris recognition devices using state-of-the-art digital signal processing (DSP) technology.

An efficient iris recognition algorithm using phase-based image matching

A major approach for iris recognition today is to generate feature vectors corresponding to individual iris images and to perform iris matching based on some distance metrics. One of the difficult problems in feature-based iris recognition is that the matching performance is significantly influenced by many parameters in feature extraction process, which may vary depending on environmental factors of image acquisition. This paper presents an efficient algorithm for iris recognition using phase-based image matching. The use of phase components in 2D (two-dimensional) discrete Fourier transforms of iris images makes possible to achieve highly robust iris recognition in a unified fashion with a simple matching algorithm. Experimental evaluation using an iris image database clearly demonstrates an efficient matching performance of the proposed algorithm.

An Iris Recognition System Using Phase-Based Image Matching

This paper presents an implementation of iris recognition algorithm using phase-based image matching-an image matching technique using phase components in 2D discrete Fourier transforms (DFTs) of given images. Our experimental observation clearly shows that the use of phase components of iris images makes possible to achieve highly accurate iris recognition even for low-quality iris images. In this paper, we consider the problem of designing a compact phase-based iris recognition algorithm especially suitable for hardware implementation. We also present prototype implementation of an iris recognition system based on the proposed algorithm. The prototype system fully utilizes state-of-the-art DSP (digital signal processor) technology to achieve real-time iris recognition capability within a compact hardware module.

A phase-based iris recognition algorithm

This paper presents an efficient algorithm for iris recognition using phase-based image matching. The use of phase components in two-dimensional discrete Fourier transforms of iris images makes possible to achieve highly robust iris recognition with a simple matching algorithm. Experimental evaluation using the CASIA iris image database (ver. 1.0 and ver. 2.0) clearly demonstrates an efficient performance of the proposed algorithm.

A palmprint recognition algorithm using Principal Component Analysis of phase information

This paper presents a palmprint recognition algorithm using Principal Component Analysis (PCA) of phase information in 2D (two-dimensional) Discrete Fourier Transforms (DFTs) of palmprint images. To achieve highly robust palmprint recognition, the proposed algorithm (i) limits the frequency bandwidth, and (ii) averages phase spectra using multiple palmprint images captured from the same hand at an enrollment stage. Through a set of experiments, we demonstrate that the proposed method can significantly reduce computational cost without sacrificing recognition performance compared with our previous work using Phase-Only Correlation (POC)—an image matching technique using the phase components in 2D DFTs of given images. Also, the resulting performance is much higher than those of conventional palmprint recognition algorithms which apply PCA to palmprint images, or phase spectra directly.

An Implementation-Oriented Iris Recognition Algorithm Using Phase-Based Image Matching

This paper presents a phase-based iris recognition algorithm which is specially designed for system implementation. In order to reduce the size of registration iris data and to prevent the visibility of iris images, we introduce the idea of 2D Fourier phase code (2D FPC) for representing iris information. 2D FPC corresponds to the quantized version of phase-spectrum of an iris image, which is essential for phase-based iris recognition. By the use of 2D FPC, while keeping a sufficient level of performance, the size of iris data can be reduced to below one-quarter compared to using iris image directly as the registration data. 2D FPC is particularly useful for implementing compact iris recognition devices using state-of-the-art DSP (digital signal processing) technology

A robot-based 3D body scanning system using passive stereo vision

This paper proposes a three-dimensional (3D) body scanning system that uses passive stereo vision with a robot arm. So far, the reported 3D body scanning systems employ active 3D measurement methods. However, active methods use structured illumination or laser scanning, which is not desirable in many systems applied to human. A major problem of using passive stereo vision for 3D measurement is its low accuracy. In addition, multiple stereo images captured from different viewpoints are necessary to cover the whole body at an appropriate distance. Addressing these problems, we have newly developed an eye-in-hand system based on passive stereo vision, where a phase-based image matching technique is employed for sub-pixel disparity estimation. Through a set of experiments, we demonstrate that the proposed system can capture 3D shape of human body with high quality.

Phase-based alignment of two signals having partially overlapped spectra

This paper proposes a novel method for aligning two signals using the information contained in the overlapped band. In particular the proposed method aligns two signals by compensating both time-delay and phase-offset in the second signal using the estimated gradient of phase difference in the overlapped band. Compared with other conventional methods, this method can align two signals without requiring a pilot tone or additional hardware. The proposed method was experimentally validated using RF pulses.