Xing Ming

A quality evaluation method of iris images sequence based on wavelet coefficients in "region of interest"

In this paper, a kind of analysis method using the wavelet coefficient in region of interest (ROI) is presented to evaluate the iris images sequence automatically. By use of Canny operator and fast Hough transform, the outer edge of the iris section is fast and accurately located. The ROI is determined according to human visual system property, at the same time, the image with acquisition deformation is filtered. Consequently, the quality evaluation factor is computed by means of the wavelet coefficient in corresponded ROI, then the iris images sequence quality is evaluated combining with the factors, such as the area of iris section and its ratio to the one of pupil section, and the experiment results indicate the correctness and validity of the method.

Using multi-matching system based on a simplified deformable model of the human iris for iris recognition

A new method for iris recognition using a multi-matching system based on a simplified deformable model of the human iris was proposed. The method defined iris feature points and formed the feature space based on a wavelet transform. In the matching stage it worked in a crude manner. Driven by a simplified deformable iris model, the crude matching was refined. By means of such multi-matching system, the task of iris recognition was accomplished. This process can preserve the elastic deformation between an input iris image and a template and improve precision for iris recognition. The experimental results indicate the validity of this method.

Multi-Matching Process Based on Wavelet Transform for Iris Recognition

As a most important biometric solution for personal identification, iris recognition has received increasing attention in recent years. Based on the features of the stochastic iris textural information and local time-frequency properties of the wavelet transform, this paper proposes a new method for iris recognition using a wavelet-based multi- matching system, which includes a coarse matching and its refinement. For the low-frequency components of the wavelet multi-resolution decomposition, a statistical correlation approach is adopted for a coarse matching so that well-matched iris templates in a database can be picked out and need to be further identified. The wavelet modulus maxima are used to locate the sharp variation points, which are taken as iris feature points. A similarity measure based on the distances between the best-matched feature point pairs is taken for the refinement of the coarse matching. Our method well employs the iris morphological characteristics and the multi-matching process to improve the efficiency. The experimental results indicate the validity of the proposed method.

Iris recognition based on quadratic spline wavelet multi-scale decomposition

This paper presents an efficient iris recognition method based on wavelet multi-scale decompositions. A two-dimensional iris image should be transformed into a set of one-dimensional signals initially and then the wavelet coefficients matrix is generated by one-dimensional quadratic spline wavelet multi-scale decompositions. From the basic principles of probability theory, the elements at the same position in different wavelet coefficients matrices can be considered as a high correlated sequence. By applying a predetermined threshold, these wavelet coefficients matrices are finally transformed into a binary vector to represent iris features. The Hamming distance classifier is adopted to perform pattern matching between two feature vectors. Using an available iris database, final experiments show promising results for iris recognition with our proposed approach.

Gabor Filter Optimization Design for Iris Texture Analysis

This paper deals with an optimization design method for the Gabor filters based on the analysis of an iris texture model. By means of analyzing the properties of an iris texture image, the energy distribution regularity of the iris texture image measured by the average power spectrum density is exploited, and the theoretical ranges of the efficient valued frequency and orientation parameters can also be deduced. The analysis shows that the energy distribution of the iris texture is generally centralized around lower frequencies in the spatial frequency domain. Accordingly, an iterative algorithm is designed to optimize the Gabor parameter field. The experimental results indicate the validity of the theory and efficiency of the algorithm.

Iris image acquirement and preprocessing in biometrics

As a biometrics, iris recognition is becoming an active topic in recent years. Due to constriction and dilation of iris sphincter muscle affected by illumination, iris images should be captured under steady illumination. The principles of our homemade iris capture device and real product are introduced first. This device can be used to capture fine iris images and store them into the computer. Due to changes of head orientation and binocular vergence at different iris acquirement time, a preprocessing method including iris location, normalization, image enhancement and rotation correction is then applied to achieve rotation, shift and scale invariance. Finally the correlation measurement is used to evaluate the performance of this processing.

Using Multi-matching System Based on a Simplified Deformable Model of the Human Iris for Iris Recognition

This paper proposes a new method for iris recognition using a multi-matching system based on a simplified deformable model of the human iris. The method defines iris feature points and forms the feature space based on a wavelet transform. In a coarse-fine manner the existence of a simplified deformable iris model is judged and its parameters are determined. By means of such multi-matching system, the task of iris recognition is accomplished. This process can preserve the deformation between two compared iris images and decrease the computation time with improving the recognition precision. The experimental results indicate the validity of this method.

Semi-physical simulation of aerodynamic effect on quartz optical window in the high-altitude and high-speed environment

Under the semi-physical simulation model, the aerodynamic pressure, aerodynamic heat effect taking place on the outer surface of optical window in the high-altitude and high-speed environment are analyzed. The first step, based on Reynolds Averaged Navier-Stokes equations, combining CFD simulation technology, aerodynamic pressure and aerodynamic heat loading on optical window were computed in different flying situation. Then, based on the calculated pressure and temperature data caused by aerodynamic effect on the optical window, experiments on aerodynamic effect simulation equipment were conducted. Theoretical and practical simulation results showed that the imaging performance of optical system was not affected by the deformation of Fused quartz glass under the aerodynamic circumstance. The semi-physical simulation model makes advices for the optical window design work and the detection of aviation spectral camera imaging performance.

Color film spectral properties test experiment for target simulation

In hardware-in-loop test of the aviation spectra camera, the liquid crystal light valve and digital micro-mirror device could not simulate the spectrum characteristics of the landmark. A test system frame was provided based on the color film for testing the spectra camera; and the spectrum characteristics of the color film was test in the paper. The result of the experiment shows that difference was existed between the landmark and the film spectrum curse. However, the spectrum curse peak should change according to the color, and the curse is similar with the standard color traps. So, if the quantity value of error between the landmark and the film was calibrated and the error could be compensated, the film could be utilized in the hardware-in-loop test for the aviation spectra camera.

Aviation spectral camera infinity target simulation system

With the development of science and technology, the applications of aviation spectral camera becoming more widely. Developing a test system of dynamic target is more important. Aviation spectral camera infinity target simulation system can be used to test the resolution and the modulation transfer function of camera. The construction and work principle of infinity target simulation system were introduced in detail. Dynamic target generator based digital micromirror device (DMD) and required performance of collimation System were analyzed and reported. The dynamic target generator based on DMD had the advantages of replacing image convenient, size small and flexible. According to the requirement of tested camera, by rotating and moving mirror, has completed a full field infinity dynamic target test plan.