Finger print and pulse sensor for digital signal processors (dsp)
- 3. Imagine how convenient it would be to activate the security alarm at your home with the touch of a finger, or to enter your home by just placing your hand on the door handle. How would you like to walk up to a nearby ATM which will scan your iris so you can withdraw money without ever inserting a card or entering a PIN. You will basically be able to gain access to everything you are authorized to, by presenting yourself as your identity. This scenario might not be as far off as we might expect. In the near future, we may no longer use passwords and PIN numbers to authenticate ourselves. These methods have proven to be insecure and unsafe time and time again. Technology has introduced a much smarter solution to us: Biometrics. Biometrics, the use of a person’s unique biological characteristics (such as face, voice, or fingerprints) for personal identification has gained a lot of popularity in recent past!!
- 4. The advantages of biometrics are becoming more apparent with the increasing use of computers in our daily life. As cyber crime increases, the need for security against identity theft becomes more and more apparent. Add to this the ever- increasing threat to personal, corporate and government assets, the need for better forms of security is obvious. Biometric authentication will help in enhancing the security infrastructure against some of these threats. After all, physical characteristics are not something that can be lost, forgotten or passed from one person to another. They are extremely hard to forge and a would-be criminal would think twice before committing a crime involving biometrics.
- 6. The Sensing Element The sensing element, or the input interface element, is the hardware core of a biometrics system and converts human biological data into digital form. This could be a complementary metal oxide semiconductor (CMOS) imager or a charge coupled device (CCD) in the case of face recognition, handprint recognition or iris/retinal recognition systems; a CMOS or optical sensor in the case of fingerprint systems; or a microphone in the case of voice recognition systems. These sensors capture the biometric information and convert it into a digital form that can be processed by the next stage - the processing element.
- 7. The Processing Element The processing element is generally a microprocessor, digital signal processor or computer that processes the data captured from the sensors. The processing of the biometric image generally involves image enhancement, normalization, template extraction, and matching/comparison of the biometric template during enrollment and authentication of the users. A programmable processor like the DSP from TI 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.
- 8. The Processing Element(contd.) 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) with the help of the multiply/accumulate (MAC) hardware inside the arithmetic logic unit (ALU). In addition, the Harvard architecture of the DSP (multiple busses) allows instruction and operand fetches in the same cycle for increased speed of operation.Developers of biometrics systems can take advantage of this architecture to enhance the resolution of the captured image with the use of two-dimensional fast fourier transforms (FFT) and finite IR filters. Because the accuracy of a system is as much dependent on the input image as it is on the processing algorithm, this helps in improving the overall accuracy and error rate of the biometrics system - a key performance metric.
- 9. The Processing Element(contd.) With the high performance capabilities of the DSP, the total recognition time of the system can be reduced without an increase in power consumption generally associated with faster processors. This low-power consumption in TI DSPs is achieved with hardware enhancements and leading-edge process technology, providing customers with a powerful, yet low-overhead processor for multiple biometric applications.
- 10. The 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. For most identification solutions (1:N), the storage element would be random access memory (RAM) or flash EPROM or some other form of memory IC, and in some other cases it could be a data server. In the case of verification (1:1), a removable storage element like a contact or contactless smart card can be used.
- 11. Interface Element Finally, there is the output interface element, which will communicate the decision of the biometric system to the interfaced asset to enable access to the user.Several ’54x devices implement a variety of types of flexible serial port interfaces. These serial port interfaces provide full duplex, bidirectional, communication with serial devices such as codecs, serial analog to digital (A/D) converters, and other serial systems. Here also we are using the same interface method!!
- 15. PULSE SENSOR
- 16. Pulse Oximeters in clinics have a finger clip type probe that has an LED on one side and a photodetector on the other side. The light emitted from one side of the finger travels through tissue, venous blood and arterial blood and is collected in the detector. Most of the light is absorbed or scattered before it reaches the photo detector in the other side of the finger. The flow of blood is heartbeat induced, or pulsatile in nature so the transmitted light changes with time. Red and infrared lights are used for pulse oximetry to estimate the true hemoglobin oxygen saturation of arterial blood. Oxyhemoglobin (HbO2) absorbs visible and infrared (IR) light differently than deoxyhemoglobin (Hb), and appears bright red as opposed to the darker brown Hb.The optical system for monitoring consists of LEDs that shine the light and a photodiode that receives the light. There are two types of optical arrangements – Transmissive and Reflective.
- 17. In the transmissive case, the photodiode and the LED are placed on opposite sides of the human body part (most commonly the finger), with the photodiode collecting the residual light after absorption from the various components of the body part. In the reflective case, the photodiode and the LED are on the same side and the photodiode collects the light reflected from various depths underneath the skin. With the conventional finger clip type probes commonly seen in a clinic, one could simply imagine that the emitted light from the LED goes straight through the tissue, interacts with blood cells somehow and continues to travel in the same direction until it reaches the photodiode, or photo detector (PD). This is not the case. Photons in the light scatter in every direction when it hits an object, for example, blood cells. LED and PD separation in the finger clip probe is around 10 mm. However, most of the photons travel 20 cm to 10 cm before reaching the PD. Some travel as long as 200 mm. The photons could be described as walking randomly. This is why glow is seen in the skin of the finger tip in following figure. If the light traveled in the straight path, that is the shortest one, how could the surrounding skin of the finger glow so bright? Since we have gotten out of the old belief that the emitter and detector have to face each other, we can try placing them in easier directions like side-by-side or even at 90 degrees.
- 19. AFE4403 Ultra-Small, Integrated Analog Front-End for Heart Rate Monitors and Low-Cost Pulse Oximeters The AFE4403 is a fully-integrated analog front-end (AFE) ideally suited for pulse oximeter applications. The device consists of a low-noise receiver channel with an integrated analog-to-digital converter (ADC), an LED transmit section, and diagnostics for sensor and LED fault detection. The device is a very configurable timing controller. This flexibility enables the user to have complete control of the device timing characteristics. To ease clocking requirements and provide a low- jitter clock to the AFE4403, an oscillator is also integrated that functions from an external crystal. The device communicates to an external microcontroller or host processor using an SPI™ interface.
- 20. P.S.: This is Reflective Type
- 21. Applications -UIDAI(Mera Aadhar Meri Pehchan) -K.Y.C(Sim,Banks,Paytm,Auth.) -Secure Entrance -Gadgets,Apple Pay,Samsung Pay -ATM:Cashless Withdrawal
- 22. Conclusion Biometrics is a truly emerging market with great potential for success. Its roots may be in science fiction, but it is part of today’s science and technology fact. In the near future, we will come to rely on biometric technology to protect our property, assets, and the people we love. We will see this technology become a secure and trusted form of authentication with uses varying from controlling access to personal information devices, to securing buildings and enabling eCommerce. DSP plays an important role in the development and adoption of biometric systems. It helps improve the performance and accuracy of these systems with its high performance architecture. The differentiation will be in enabling multiple new applications with smart biometric solutions powered by a DSP. All of this can be achieved at a low overall system cost as a result of design reuse and faster time-to-market. This, in turn will help create a growth market for affordable intelligent security systems. In conclusion, using DSP as the embedded processor of choice for enabling smart biometric systems can provide the following advantages: • Fast, accurate, secure and trusted authentication • Enable new applications with one scalable design • Reduce overall cost of development
- 23. References 1) https://www.ti.com/jp/lit/wp/spra894a/spra894a.pdf 2) http://www.ti.com/data-sheets/diagram.tsp?genericPartNumber=AFE4403&diagramId=SBAS650B 3) http://www.ti.com/lit/an/slaa655/slaa655.pdf 4) ti.com/lit/ug/spru173/spru173.pdf 5) The Light-Tissue Interaction of Pulse Oximetry: by Paul D. Mannheimer, PhD., December 2007. 6) Pulse Oximeter Fundamentals and Design: by Santiago Lopez, September 2011