Masuyoshi Yachida

Experimental evaluation of fingerprint verification system based on double random phase encoding.

We proposed a smart card holder authentication system that combines fingerprint verification with PIN verification by applying a double random phase encoding scheme. In this system, the probability of accurate verification of an authorized individual reduces when the fingerprint is shifted significantly. In this paper, a review of the proposed system is presented and preprocessing for improving the false rejection rate is proposed. In the proposed method, the position difference between two fingerprint images is estimated by using an optimized template for core detection. When the estimated difference exceeds the permissible level, the user inputs the fingerprint again. The effectiveness of the proposed method is confirmed by a computational experiment; its results show that the false rejection rate is improved.

Least-squares filter for color-image restoration

A least-squares filter for restoration of blurred color images was developed directly from spectral and spatial correlations and on the basis of a mathematical model that assumes that spectroscopic images of an object are specified by spectral vectors and that a set of such orthonormal vectors forms a multidimensional color space. Primary colors are expressed by a linear combination of spectral vectors, and color images are given by the projection of spectroscopic images onto the primary color or observation vectors. Detailed discussions and a computer simulation are presented.

Compensation of motion blur in CCD color endoscope images.

Color CCD endoscopes with sequential three-color illuminations have the advantage of high spatial resolution but are sensitive to object motion. A digital method is proposed for the restoration of images color-shifted by the object motion. The method makes use of phase-only matching followed by a resampling operation to compensate for a space-variant shift between different primary color images. Restored images are suitable for further image processing such as color emphasis and structure enhancement.

Image restoration using synthetic image processing method

Abstract A new image restoration method which synthesizes the Fourier components from those of several degraded images is introduced. Three examples, the spectrum selection, the least square estimation and the weighted mean proportional to the magnitude of the power spectrum, are described. The experimental results show that this technique is effective for image restoration.

File Encryption Software Using Fingerprint Keys Based on Double Random Encoding

The encryption method based on double random phase encoding makes it possible to use the fingerprints as cipher key. Applying this technique, we develop a file encryption software which can use fingerprint as cipher key.

Color image restoration using synthetic method

Abstract A color image restoration method is developed. The Fourier spectrum of a restored image is synthesized from the Fourier spectra of three primary color bands of a given degraded image. The synthesizing weights depend upon the evaluation of the final restored image. Two examples, the weights which minimize the mean square error and the weights which are expressed as the weighted mean proportional to the magnitude of the power spectra, are shown. This restoration method is shown to be effective especially when three primary color images strongly correlate to each other.

A new method for constructing dynamic VPN cooperating with OpenFlow control technology and healthcare PKI

In dealing with medical information of patients through the network, high-level security is required. In Japan, the Ministry of Health, Labor and Welfare has issued the Security Guidelines for Health Information Systems which stipulates that proper measures should be taken for the network to preserve the patient data. The guideline also state that the management of the network must clarify demarcation of responsibility between network service providers including user. To keep the security regulation in communicating with external organizations, many medical institutions use several managed-VPN service lines separately according to the usages. It is because to avoid the risk of forming a virtual detour which can be used to leak the patient data. This makes the hospital bear the cost and inconvenience. To solve this problem, we propose a new secure network implementation method using single-line VPN network service for small-scale medical institution by arranging OpenFlow control technology with Healthcare PKI. The network works over a dynamic on-demand VPN with control based on the user certification responding their qualification, such as a medical doctor, written in the HPKI digital certificates. We developed a simple network system adopting our new method, and confirmed the validity and the effectiveness of our idea through the experiment.

New secure communication-layer standard for medical image management (ISCL)

This paper introduces a summary of the standard draft of ISCL 1.00 which will be published by MEDIS-DC officially. ISCL is abbreviation of Integrated Secure Communication Layer Protocols for Secure Medical Image Management Systems. ISCL is a security layer which manages security function between presentation layer and TCP/IP layer. ISCL mechanism depends on basic function of a smart IC card and symmetric secret key mechanism. A symmetry key for each session is made by internal authentication function of a smart IC card with a random number. ISCL has three functions which assure authentication, confidently and integrity. Entity authentication process is done through 3 path 4 way method using functions of internal authentication and external authentication of a smart iC card. Confidentially algorithm and MAC algorithm for integrity are able to be selected. ISCL protocols are communicating through Message Block which consists of Message Header and Message Data. ISCL protocols are evaluating by applying to regional collaboration system for image diagnosis, and On-line Secure Electronic Storage system for medical images. These projects are supported by Medical Information System Development Center. These project shows ISCL is useful to keep security.

Development of a secure archiving device for medical record archiving

A prototype secure archiving device have been developed for digital record systems that has the same preservability, viewability, and integrity as paper and film based systems. The device can manage a variety of digital recording media with the security level. We evaluated the device in a medical environment by connecting it to an existing medical record archiving system. The device satisfies the criteria that the Japanese Ministry of Health and Welfare has announced for regulating digital medical records.

Network security system for health and medical information using smart IC card

A new network security protocol that uses smart IC cards has been designed to assure the integrity and privacy of medical information in communication over a non-secure network. Secure communication software has been implemented as a library based on this protocol, which is called the Integrated Secure Communication Layer (ISCL), and has been incorporated into information systems of the National Cancer Center Hospitals and the Health Service Center of the Tokyo Institute of Technology. Both systems have succeeded in communicating digital medical information securely.