Biometrics 简明教程

Signal Processing and Biometrics

在现实世界中，我们可以获得各种信号，例如声音、光、无线电信号、来自人体的生物医学信号等。所有这些信号都以连续的信息流（称为模拟信号）的形式出现。人声是我们从现实世界中获得的信号，并用作生物特征输入。

There are various signals we can get in the real world such as sound, light, radio signals, biomedical signals from human body, etc. All these signals are in the form of a continuous stream of information, called analog signals. Human voice is a kind of signal we get from the real world and use as biometric input.

What is a Signal?

信号是可以传达、显示、记录或修改的，包含某些信息的可测量物理量。

A signal is a measurable physical quantity containing some information, which can be conveyed, displayed, recorded, or modified.

signal

Signal Processing in Biometrics

处理信号的原因有很多。生物特征系统需要进行语音处理出于多种原因——

There are various reasons for processing signals. The biometric systems, require voice processing for various reasons −

  1. To extract meaningful information from the candidate’s sample.

  2. To remove noise from the sample.

  3. To make the sample transmittable.

  4. To remove distortion of sample.

模拟信号处理模块将现实世界中的信息（例如声波）转换为 0 和 1 的形式，使其易于现代数字系统（例如生物识别系统）理解和使用。击键、手部几何形状、签名和语音属于信号处理和模式识别的领域。

The analog signal processing module converts real world information such as sound wave in the form of 0s and 1s to make it understandable and usable by the contemporary digital systems such as biometric systems. The keystrokes, hand geometry, signature, and speech fall into the domains of signal processing and pattern recognition.

Digital Signal Processing Systems (DSPs)

有两种类型的信号——模拟和数字。模拟信号是信息的不间断连续流，而数字信号是 0 和 1 的流。

There are two types of signals − analog and digital. The analog signals are uninterrupted, continuous stream of information whereas digital signal is a stream of 0s and 1s.

DSP 系统是生物特征系统的重要组成部分之一，它通过使用模数转换器 (ADC) 采样和数字化，将模拟信号转换为离散数字值的流。

DSP systems are one of the important components of biometric systems, which convert analog signals into a stream of discrete digital values by sampling and digitizing using an Analog-to-Digital Converter (ADC).

DSP 是单芯片数字微型计算机，处理来自摄像头、指纹传感器、麦克风等的电子传感器产生的电信号。

DSPs are single-chip digital microcomputers, which process electrical signals generated by electronic sensors from cameras, fingerprint sensors, microphones, etc.

DSP in Biometrics

DSP 使生物识别系统小巧便携，运行高效，整体成本更低。

A DSP allows the biometric system to be small and easily portable, to perform efficiently and to be overall less costly.

DSP 架构旨在支持复杂的数学算法，其中涉及大量的乘法和加法。DSP 可以借助算术逻辑单元 (ALU) 中的乘累加 (MAC) 硬件在一个周期内执行乘/加。

The DSP architecture is built to support complex mathematical algorithms that involve a significant amount of multiplication and addition. The DSP can execute multiply/add in a single cycle with the help of the multiply/accumulate (MAC) hardware inside its Arithmetic Logic Unit (ALU).

它还可以使用二维快速傅里叶变换 (FFT) 和有限 IR 滤波器来提高捕获图像的分辨率。

It can also enhance the resolution of the captured image with the use of two-dimensional Fast Fourier Transforms (FFT) and finite IR filters.