Transcript BioSignal Processing - jrcanedo's E

BioSignal
Processing
Introduction
Biological signals or biosignals
Are space, time, or space–time records of a
biological event such as a beating heart or a
contracting muscle. The electrical, chemical, and
Mechanical activity that occurs during these biological
event often produces signals that can be measured
and analyzed.
Contain useful information that can be used to
understand the underlying physiological mechanisms
of a specific biological event or system, and which
may be useful for medical diagnosis.
Introduction
Digital processing methods
Data acquisition
 Using stethoscope to listen to patient’s heart
Signal analysis
Retrieve useful information
• Amplification
• Filtering
• Digitization
• Processing
• Storage
Physiological Origins of
Biosignals
Bioelectric Signals
Generated by nerve and muscle cells as a result of
electrochemical changes within and between cells
Can be measured with intracellular or extracellular
electrodes
ECG, EGG, EEG, and EMG are results of the
Bioelectric signals taken from the human body
Physiological Origins of
Biosignals
Biomagnetic Signals
Different organs(heart, lungs & brain) generate
weak magnetic fields
Measured from specific physiological activity that is
linked to an accompanying electric field from a
specific tissue or organ
Uses very precise magnetic sensors or SQUID
magnetometers (Superconducting Quantum
Interference Device)
Physiological Origins of
Biosignals
Bio magnetic Signals (cont.)
Magnetoencephalography (MEG) - monitor
magnetic activity from the brain
Magnetoneurography (MNG) – monitor peripheral
nerves
Magnetogastrography (MGG) – monitor
gastrointestinal tract
Magnetocardiography (MCG) – monitor the heart
Physiological Origins of
Biosignals
Biochemical Signals
Contain information about changes in concentration
of various chemical agents in the body
Oxygen concentration
Determine levels of glucose, lactate and
metabolites
Provides information about the function of various
physiological systems
Physiological Origins of
Biosignals
Biomechanical Signals
Produced by the mechanical functions of biological
signals such as:
• motion, displacement, tension, force, pressure,
and flow
Blood pressure measurement
Physiological Origins of
Biosignals
Bioacoustic Signals
Are special subset of biomechanical signals that
involve vibrations (motion)
Respiratory system, joints, and muscles generate
distinct bioacoustic signals
Often measured at the skin using acoustic
transducers such as microphones and
accelerometers
Physiological Origins of
Biosignals
Biooptical Signals
Generated by the optical, or light-induced, attributes
of biological systems
May occur naturally or signals can be introduced to
measure a biological parameter using an external
light medium
Characteristics of
Biosignals
Biosignals can be classified according to various
characteristics:
Waveform Shape
Statistical Structure
Temporal Properties
2 broad classes of signals:
Continuous
Discrete
Characteristics of
Biosignals
Continuous Signals
Defined over a continuum of time or space and are
described by continuous variable functions
Produced by biological phenomena:
• Like voltage measurements from the heart
• Arterial blood pressure measurements
• Measurements of electrical activity from the brain
Characteristics of
Biosignals
Discrete Signals
Defined only at a subset of regularly spaced points
in time and/or space
Commonly used in today’s clinical setting
Continuous signals from human body are converted
to discrete signals that can be analyzed and
interpreted by a computer