image processing vs signal processing?

What are the differences between image processing and signal processing? All i know is only that images are 2 dimensional while signals are n dimensional(where n can be 1,2,3,4 or any number). Please correct me if i am wrong?

[Meg Noah]

To me, it isn't about the dimensionality or units of the data, but rather about what you are looking for. Signal processing is about finding a signal. The signal is some sort of feature or signature from a source (natural or manmade). Detecting the signal is confounded by noise that is natural from the environment, artifacts introduced by the measurement equipment, and the nature of signal generation which has statistical uncertainty. Image processing, to my way of thinking, is a superset of signal processing. Image processing may involve itself with characterizing the background or environment of the image as well as the features. Both are concerned with characterization of the features and signals that are detected, and can involve categorical annotation of data. Some people might regard it the other way around: that image processing is a subset of signal processing. It depends on your point of view, and some people consider these in terms of artificial or enhanced vision and hearing.