第1个回答 2011-09-26
我给你一段英文经典教材里的话：
主要是说当信号划分为一维二维三维的时候，二维信号就可以当做信号来处理。
因为是x和y在不同的坐标水平变化。
An image is a subset of a signal. A signal is a function that conveys information
generally about the behavior of a physical system or attributes of some phenomenon.
Asimple example is the traffic signal that uses three universal color codes (red, yellow,
and green) signaling the moment to stop, drive, or walk. Although signals can be
represented in many ways, in all cases the information is contained in a pattern of
variations of some form, and with that information is typically transmitted and
received over a medium. Electrical quantities such as current and voltage are called
electrical signals, which are often used in radio, radar, sonar, telephone, television,
and many other areas. An acoustic wave signal can convey speech or music
information, in which people often speak of a strong or weak signal when the sound
is referred to its clarity and audibility. A thermocouple can convey temperature, and a
pH meter can convey the acidity of a solution.
Two-Dimensional Signals
Signal processing problems are not confined to 1Dsignals.A2Dsignal is a function of
two independent variables, for example, f x; y . In particular, one is concerned with
the functional behavior in the form of an intensity variation over the (x, y)-plane.
Everyday scenes viewed by a human observer can be considered to be composed of
illuminated objects. The light energy reflected fromthese objects can be considered to
form a 2D intensity function, which is commonly referred to as an image.
As a result of numerous applications, not least as a consequence of cheap
computer technology, image processing now influences almost all areas of our daily
life: automated acquisition, processing and production of documents, industrial
process automation, acquisition and automated analysis of medical images, enhance-
ment and analysis of aerial photographs for detection of forest fires or crop damage,
analysis of satelliteweather photos, and enhancement of television transmission from
lunar and deep-space probes.