FINGERPRINT BIOMETRICS

ESD PRESENTATION GROUP 2

BIOMETRICS• Biometrics (or biometric authentication refers

to the identification of humans by their characteristics or traits. Biometrics is used in computer science as a form of identification and access control. It is also used to identify individuals in groups that are under surveillance

TYPES OF BIOMETRICS

• DNA MATCHING• EAR• EYES-IRIS RECOGNITION• VOICE RECOGNITION• FACE• FINGERPRINT RECOGNITION• FINGER GEOMETRY RECOGNITION• SO ON….

WHY FINGERPRINTS

• Very high accuracy.• Is the most economical biometric PC user

authentication technique.• it is one of the most developed biometrics• Easy to use.• Small storage space required for the biometric

template, reducing the size of the database memory required

• It is standardized.

IT’S AN EMBEDDED SYSTEM!!!!!

BASIC ELEMENTS OF A TYPICAL FINGERPRINT BIOMETRIC SYSTEM

• Sensing

• Processing

• Storage

• Interface

Biometrics System Elements

THE SENSOR

Types of Sensors

Optical

Capacitive

Thermal

Pressure

OPTICAL • Heart of an optical

sensor is a Charged Couple Device ( CCD): an array of light sensitive diodes called photosites which generate an electrical signal in response to light photons.

Working

• Photosite records pixels.• Ridges and valleys present on fingers are illuminated

• CCD processor ensures a clear image is taken• Definition of the image is checked

• Collectively pixels form an image• A to D Converter generates digital representation of image

How capacitive touch

works

Frequency Change method

• An oscillator that oscillates at a high frequency (usually 10 to 50 KHz), and uses a capacitor to oscillate.

555 multivibrator Capacitance of 10pF (Body capacitance is about

15pF)

Note : We use a small capacitance of 10pF because the body capacitance is small as well, usually from 8 to 15 pF. So, the capacitor C must be around this value, so that the body capacitance will have a big influence to the overall capacitance.

• The touch sensor is placed in parallel with this capacitor, or some times the touch sensor is the capacitor itself.

• If the touch sensor is touched by a finger, then the body capacitance is connected in parallel to the sensor's capacitance.

• As you may know, the overall capacitance of two capacitors connected in parallel is increased (connecting capacitors), and this causes the oscillating frequency to change (bigger capacitor means lower frequency).

Before detecting touch After detecting touch

• Using a digital comparator or any other method to sense this frequency change, one can determine if the touch pad is touched.

The frequency comparator – • There are several ways to implement such a circuit. • One of them, is to convert the frequency into a DC voltage with a

Frequency to Voltage converter, and compare it to a fixed DC voltage. This method is widely used in analog applications.

The output stage –

• A Schmidt trigger compares the output values from the frequency comparator & it’s output leads to the LED which glows when a touch is detected.

Capacitive Voltage Divider method

• This is another very interesting technique to implement a touch sensor.

• The touch pad is directly connected to the Analog to Digital converter of a microcontroller.

• Here is a rough diagram of the circuit:

• The ADC module is internally driven to VDD, so that the capacitor used for the A/D conversion is fully charged

• The analog input (sensor) is internally disconnected from the ground

• The ADC module is internally connected to the Analog Input (sensor)

• The analog input (sensor) is internally grounded, so that the sensor is fully discharged

• Internal capacitor will discharge part of its charge to the sensor (or human body).

• At the end, both capacitors (the internal and the sensor) will have the same voltage across them. This voltage depends on the capacitance of the sensor.

• When the voltage is divided, it will be times smaller than the original charge of the internal capacitor.

• So, immediately after step 4, the microcontroller starts an analog to digital conversion and reads the ADC module registers.

• According to the voltage that it reads, it can be determined if the sensor is touched or not.

• This method is extremely simple to implement with a microcontroller, because the only external part required is the sensor. It is completely improper to

implement without a microcontroller.

THE PROCESSOR

WHY DSP OVER MC

• A programmable processor like the DSP can address all the processing needs of a biometric system while providing the most viable path to standards and feature upgrades.

• A DSP allows the product to be small and portable while maintaining power-efficient performance all at a low overall system cost.

• The DSP architecture is built to support complex mathematical algorithms that involve a significant amount of multiplication and addition.

• The DSP executes the multiply/add feature in a single cycle (compared to multiple cycles for RISC processors)

• In addition, the Harvard architecture of the DSP (multiple busses) allows instruction and operand fetches in the same cycle for increased speed of operation.

BASIC BLOCK DIAGRAM

GENERAL PURPOSE INPUT/OUTPUT (GPIO)

• It is a generic pin on a chip whose behavior (including whether it is an input or output pin) can be controlled (programmed) by the user at run time.

• GPIO pins have no special purpose defined, and go unused by default. The idea is that sometimes the system integrator building a full system that uses the chip might find it useful to have a handful of additional digital control lines, and having these available from the chip can save the hassle of having to arrange additional circuitry to provide them.

THE SERIAL PERIPHERAL INTERFACE SPI-BUS

• It is a simple 4-wire serial communications interface used by many microprocessor/microcontroller peripheral chips that enables the controllers and peripheral devices to communicate each other. Even though it is developed primarily for the communication between host processor and peripherals, a connection of two processors via SPI is just as well possible.

SPI BUS

• An SPI protocol specifies 4 signal wires.

• Master Out Slave In (MOSI) - MOSI signal is generated by Master, recipient is the Slave.

• Master In Slave Out (MISO) - Slaves generate MISO signals and recipient is the Master.

• Serial Clock (SCLK or SCK) - SCLK signal is generated by the Master to synchronize data transfers     between the master and the slave.

• Slave Select (SS) from master to Chip Select (CS) of slave - SS signal is generated by Master to     select individual slave/peripheral devices. The SS/CS is an active low signal.

• The SPI bus, which operates at full duplex (means, signals carrying data can go in both directions simultaneously), is a synchronous type data link setup with a Master / Slave interface and can support up to 1 megabaud or 10Mbps of speed. Both single-master and multi-master protocols are possible in SPI.

• To begin a communication, the bus master first configures the clock, using a frequency less than or equal to the maximum frequency the slave device supports. Such frequencies are commonly in the range of 1–100 MHz.

• During each SPI clock cycle, a full duplex data transmission occurs:

• the master sends a bit on the MOSI line; the slave reads it from that same line

• the slave sends a bit on the MISO line; the master reads it from that same line

A typical hardware setup using two shift registers to form an inter-chip circular buffer

IMAGE ENCODING

STORAGE ELEMENT

• The function of the storage element is to store the enrolled template that is recalled to perform a match at the time of authentication.

• DSPs have varying sizes of internal RAM to address the image processing and template extraction processes of the various biometric algorithms, along with read-only memory (ROM) for storing the constant parts of the programming code.

LDO

• A low-dropout or LDO regulator is a DC linear voltage regulator which can operate with a very small input–output differential voltage.

• The advantages of a low dropout voltage include a lower minimum operating voltage, higher efficiency operation and lower heat dissipation.

COMPONENTS OF LDO

• The main components are a power FET and a differential amplifier (error amplifier).

• There are two inputs to the differential amplifiers.

• Low-dropout (LDO) regulators work in the same way as all linear voltage regulators.

• The main difference between LDO and non-LDO regulators is their schematic topology.

ESD PROTECTION

• Electrostatic discharge (ESD) is the sudden flow of electricity between two objects caused by contact, an electrical short or dielectric breakdown.

• . ESD can be caused by a buildup of static electricity by turbocharging, or by electrostatic induction.

CHARACTERISTICS OF THE PROTECTION

Extremely fast response time

Low clamping and operating voltages

Capacity to handle high peak ESD currents

Ability to remain undamaged by repetitive ESD strikes

Minimal size

BASIC BLOCK DIAGRAM

FUTURE PROSPECTS

• Public Sector Application : eBorders, eID, and eGovernment.

• Commercial Application : Enterprise Security, Information Transactions, Financial Transactions.

• Technology Evolution : Secure Identity Core, Secure Mobility, Secure Credentials, and Secure Transactions.

EXAMPLES