Contrast Adaptation
Fuzzy Approaches versus Histogram Equalization

Methods

• Adaptive fuzzy rule-based approach (AFRB)

• Adaptive fuzzy histogram hyperbolization (AFHH)

• Adaptive fuzzy intensification operator (AFIO)

• Adaptive histogram equalization (AHE)

Locally adaptive implementation

• Parameters of all methods are calculated in subimages (see Fig.1)

• The size of subimages and the degree of their overlapping is the same or all methods

• The necessary values are then interpolated (e.g. histograms, membership functions, ...)

Some results

Original image with poor dynamics

after AHE	after AFHH
after AFRB	after AFIO

Fig. 2. Comparison between fuzzy methods and histogram equalization.

 
Computing time: AFHH versus AHE

Fig. 3. Using portal images (cancer treatment) the computing time of AFHH was compared with AHE.