[Interview] Sony Discusses Finger Vein Authentication System for Mobile Devices

Mar 9, 2009
Tadashi Nezu, Nikkei Electronics
A prototyped finger vein authentication system. Users are verified by placing their fingers on the small device in the bottom right.
A prototyped finger vein authentication system. Users are verified by placing their fingers on the small device in the bottom right.
[Click to enlarge image]
A finger placed on the finger vein authentication system. Near-infrared LEDs are located above the finger.
A finger placed on the finger vein authentication system. Near-infrared LEDs are located above the finger.
[Click to enlarge image]

Sony Corp developed "mofiria," a finger vein authentication technology for PCs and mobile devices such as cell phones (Press release). The company expects that the technology will more easily downsize those devices than existing palm vein and finger vein authentication systems.

This time, Nikkei Electronics interviewed General Manager Satoshi (Steve) Amagai and Technology Manager Ken Iizuka at FVA Business Development Office in FeliCa Business Division, B2B Solutions Business Group of Sony, about mofiria's characteristics and underlying technologies as well as the company's business plan. (Interviewer: Tadashi Nezu)

Q: Please explain the characteristics of the new finger vein authentication technology?

Sony: Its biggest feature is the capability to make a finger vein authentication system small enough to be embedded in a mobile device. It is difficult with existing technologies.

Moreover, we achieved accuracy as high as that of general finger vein authentication systems while increasing its authentication processing speed. It's stressful when authentication process is slow. So, we aimed at enhancing user convenience and security level at the same time.

It took 0.015 seconds for mofiria to recognize an individual using Intel Corp's microprocessor (2.8GHz) for notebook PCs, and 0.25 seconds using an ARM9 core-based microprocessor (150MHz) for mobile phones. As for accuracy, its false rejection rate (FRR) was 0.1%, and its false acceptance rate (FAR) was 0.0001%, meeting the criteria for finger vein authentication systems.

Q: How did you realize those capabilities?

Sony: As for technical aspects, mofiria's advantages lie in its simple device structure, methods to acquire vein pattern data and compress them, and function to adjust the finger position, to name a few.

The technology enables to simplify finger vein authentication systems thanks to the adoption of the "reflection scattering method," which directs near-infrared rays from LEDs at finger veins at an angle and uses a CMOS sensor to catch light reflected and scattered in the finger. With this method, verification systems can be made smaller because LEDs and CMOS sensor can be positioned on the same level in a system.

The process to acquire finger vein pattern data can be roughly divided into three stages. First, the CMOS sensor takes the image of light reflected and scattered in a finger. Due to "reduced hemoglobin" in blood, which absorbs near-infrared rays, veins look dark.

Second, a vein pattern is extracted through several filtering processes, including a process for removing noise. Third, the vein pattern is converted into an image called a "skeleton pattern," in which the thickness of the pattern lines is equal regardless of area.

This conversion is necessary because the thickness of the vein pattern varies as the volume of blood flow changes in accordance with location and environment. Thus, for reliable authentication, this skeleton pattern plays an important role.

(Continue to the next page)