6. De-noising
Estimation of noise parameters:
* By spectrum inspection: for periodic noise
* By test image: mean, variance and histogram shape,
if imaging system is available
* By small patches, if only image is available
De-noising :
1. Spatial filtering ( for additive noise)
* Mean filters
* Order-statistics filters
* Adaptive filters
2. Frequency domain filtering (for periodic noise)
10. Degradation models: linear vs non-linear
1. Many types of degradation can be approximated
by linear, space invariant processes
* Can take advantages of the mature
techniques developed for linear systems
2. Non-linear and space variant models are more
accurate
* Difficult to solve
* Unsolvable