Biomedical Signal processing Chapter 1 Introduction

1
Biomedical Signal processingChapter 1
Introduction

• ???Zhongguo Liu
• Biomedical Engineering
• School of Control Science and Engineering,
  Shandong University

2015-3-17
1
Zhongguo Liu_Biomedical Engineering_Shandong Univ.
2
Self Introduction
???liuzhg_at_sdu.edu.cn cellphone18764171197
Tel84192
???????????????(??) http//course.sdu.edu.cn/bds
p.html
Zhongguo Liu_Biomedical Engineering_Shandong Univ.
2
2015-3-17
3
Chapter 1 Introduction

• Signal processing is benefited from a close
  coupling between theory, application, and
  technologies for implementing signal processing
  systems.
• Signal processing deals with the representation,
  transformation, and manipulation of signals and
  the information they contain.

Zhongguo Liu_Biomedical Engineering_Shandong Univ.
3
2015-3-17
4
Continuous and Digital Signal Processing

• Prior to 1960 continuous-time analog signal
  processing.
• Digital signal processing is caused by
• the evolution of digital computers and
  microprocessors
• Important theoretical developments such as the
  Fast Fourier Transform algorithm (FFT)

Zhongguo Liu_Biomedical Engineering_Shandong Univ.
4
2015-3-17
5
Digital and Discrete-time Signal Processing

• In digital signal processing
• Signals are represented by sequences of
  finite-precision numbers
• Processing is implemented using digital
  computation
• Digital signal processing is a special case of
  discrete-time signal processing

Zhongguo Liu_Biomedical Engineering_Shandong Univ.
5
2015-3-17
6
Digital and Discrete-time Signal Processing

• Continuous-time signal processing time and
  signal are continuous
• Discrete-time signal processing
• time is discrete, signal is continuous
• Digital signal processing
• time and signal are discrete

Zhongguo Liu_Biomedical Engineering_Shandong Univ.
6
2015-3-17
7
Discrete-time Processing

• Discrete-time processing of continuous-time signal

ideal continuous-to-discrete-time (C/D) converter
ideal discrete-to-continuous-time (D/C) converter

• Real-time operation is often desirable output is
  computed at the same rate at which the input is
  sampled

Zhongguo Liu_Biomedical Engineering_Shandong Univ.
7
2015-3-17
8
Objects of Signal Processing

• Process one signal to obtain another signal
• Signal interpretation Characterization of the
  input signal.

Example speech recognition
Zhongguo Liu_Biomedical Engineering_Shandong Univ.
8
2015-3-17
9
Objects of Signal Processing

• Symbolic manipulation of signal processing
  expression signal and systems are represented
  and manipulated as abstract data objects, without
  explicitly evaluating the data sequence.

Zhongguo Liu_Biomedical Engineering_Shandong Univ.
9
2015-3-17
10
Chapter 1 Introduction

• Applications of signal processing entertainment,
  communications, space exploration, medicine,
  archaeology, etc.
• Role of signal processing is expanding, driven by
  convergence of computers, communications and
  signal processing.

Zhongguo Liu_Biomedical Engineering_Shandong Univ.
10
2015-3-17
11
Processing of biomedical signals
12
Processing of biomedical signals

• Processing of biomedical signals is application
  of signal processing methods on biomedical
  signals
• ?All possible processing algorithms may be used
• ?Biomedical signal processing requires
  understanding the needs (e.g. biomedical
  processes and clinical requirements) and
  selecting and applying suitable methods to meet
  these needs

13
(No Transcript)
14
(No Transcript)
15
Example heart rate meters
Signal processing
Sensor
User
16
Example IST Vivago WristCare
17
(No Transcript)
18
Health monitoring
Systolic and diastolic blood pressure
Beat-to-beat heart rate

• Need for processing to
• draw any conclusions

19
Why do We Learn DSP

• Software, such as Matlab, has many tools for
  signal processing.
• It seems that it is not necessary to know the
  details of these algorithms, such as FFT.
• A good understanding of the concepts of
  algorithms and principles is essential for
  intelligent use of the signal processing software
  tools.

Zhongguo Liu_Biomedical Engineering_Shandong Univ.
19
2015-3-17
20
Extension

• Multidimensional signal processing
• image processing
• Spectral Analysis
• Signal modeling
• Adaptive signal processing
• Specialized filter design
• Specialized algorithm for evaluation of Fourier
  transform
• Specialized filter structure
• Multirate signal processing
• Wavlet transform

Zhongguo Liu_Biomedical Engineering_Shandong Univ.
20
2015-3-17
21
Historical Perspective

• 17th century
• The invention of calculus
• Scientist developed models of physical phenomena
  in terms of functions of continuous variable and
  differential equations
• Numerical technique is used to solve these
  equations
• Newton used finite-difference methods which are
  special cases of some discrete-time systems

Zhongguo Liu_Biomedical Engineering_Shandong Univ.
21
2015-3-17
22
Historical Perspective

• 18th century
• Mathematicians developed methods for numerical
  integration and interpolation of continuous
  functions
• 19th century
• Gauss (1805)discovered the fundamental principle
  of the Fast Fourier Transform (FFT) even before
  the publication(1822) of Fourier's treatise on
  harmonic series representation of function
  (proposed in 1807)

Zhongguo Liu_Biomedical Engineering_Shandong Univ.
22
2015-3-17
23
Historical Perspective

• Early 1950s
• signal processing was done with analog system,
  implemented with electronics circuits or
  mechanical devices. first uses of digital
  computers in digital signal processing was in oil
  prospecting.
• Simulate signal processing system on a digital
  computer before implementing it in analog
  hardware, ex. vocoder

Zhongguo Liu_Biomedical Engineering_Shandong Univ.
23
2015-3-17
24
Historical Perspective

• With flexibility the digital computer was used to
  approximate, or simulate, an analog signal
  processing system
• The digital signal processing could not be done
  in real time
• Speed, cost, and size are three of the important
  factors in favor of the use of analog components.
• Some digital flexible algorithm had no
  counterpart in analog signal processing,
  impractical. all-digital implementation tempting

Zhongguo Liu_Biomedical Engineering_Shandong Univ.
24
2015-3-17
25
Historical Perspective

• FFT discovered by Cooley and Tukey in 1965
• an efficient algorithm for computation of Fourier
  transforms, which reduce the computing time by
  orders of magnitude.
• FFT might be implemented in special-purpose
  digital hardware
• Many impractical signal processing algorithms
  became to be practical

Zhongguo Liu_Biomedical Engineering_Shandong Univ.
25
2015-3-17
26
Historical Perspective

• FFT is an inherently discrete-time concept. FFT
  stimulated a reformulation of many signal
  processing concepts and algorithms in terms of
  discrete-time mathematics, which formed an exact
  set of relationships in the discrete-time domain,
  so there emerged a field of discrete-time signal
  processing.

Zhongguo Liu_Biomedical Engineering_Shandong Univ.
26
2015-3-17
27
Historical Perspective

• The invention and proliferation of the
  microprocessor paved the way for low-cost
  implementations of discrete-time signal
  processing systems
• The mid-1980s, IC technology permitted the
  implementation of very fast fixed-point and
  floating-point microcomputer.
• The architectures of these microprocessor are
  specially designed for implementing discrete-time
  signal processing algorithm, named as Digital
  Signal Processors(DSP).

Zhongguo Liu_Biomedical Engineering_Shandong Univ.
27
2015-3-17
28
Goals of the course

• To understand what biomedical signals are
  what problems and needs are related to their
  acquisition and processing
• what kind of methods are available and get an
  idea of how they are applied and to which kind of
  problems
• To get to know basic digital signal processing
  and analysis techniques commonly applied to
  biomedical signals and to know which kind of
  problems each method is suited for (and for which
  not)

Zhongguo Liu_Biomedical Engineering_Shandong Univ.
28
2015-3-17