This dissertation shows how fuzzy systems can help compress image sequences. The fuzzy systems filter noise and improve motion estimation and compensation. Adaptive fuzzy systems further improve the compensation accuracy. The dissertation describes th...
This dissertation shows how fuzzy systems can help compress image sequences. The fuzzy systems filter noise and improve motion estimation and compensation. Adaptive fuzzy systems further improve the compensation accuracy. The dissertation describes three applications of fuzzy imagesequence compression: fuzzy filters for impulsive noise, fuzzy virtual tilings for subband image coding, and fuzzy motion estimation and compensation.
Fuzzy systems of if-then rules can filter impulsive noise from signals. An additive fuzzy system learns ellipsoidal fuzzy rule patches from a new pseudo-covariation measure of alpha-stable covariation. Mahalanobis distance gives a joint set function for the learned if-part fuzzy sets of the if-then rules. The joint set function preserves input correlations that standard factored set functions ignore. The fuzzy system filtered such noise better than did a benchmark radial basis neural network.
A fuzzy system can improve how subband coding compresses images. A fuzzy system maps the coefficients of frequency subbands to virtual tiles of the time-frequency plane. This prunes the tiling tree and gives a high-energy subtree. The new tiling subtree shapes the error spectrum and helps preserve edges in the image.
A fuzzy system can also estimate motion vectors and increase the compensation accuracy for video compression. The fuzzy system uses the temporal correlation of the motion field to estimate the motion vectors. First and second order statistics of the motion vectors give ellipsoidal search windows. Out algorithm reduced the search area and gave clustered motion fields. We also proposed a fuzzy overlapped block motion compensator. The fuzzy system uses the motion vectors of neighboring blocks to map the previous frame's pixel values to the current pixel value. The rules come from the previously decoded frame. The fuzzy system updates its rules as it decodes the image. The fuzzy system also improved the compensation accuracy.