07-02-2012, 04:48 PM
Digital Image Processing for Radiographers
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Sampling & Quantisation
• The spatial and amplitude digitization of
f(x,y) is called:
– image sampling when it refers to spatial
coordinates (x,y) and
– gray-level quantization when it refers to
the amplitude.
Perceived Image Quality & Resolution
• Different versions (images) of the same
object can be generated through:
– Varying N, M numbers
– Varying k (number of bits)
– Varying both
• Huang 1965 – Isopreference Curves
Summary
Definitions of Sampling & Quantisation
Representing Digital Images
Spatial & Gray-level resolution
Perceived Image Quality & Resolution
Aliasing & Moire patterns
