US 6,034,741 AGranted

Fuzzy logic filter for impulsive noisy images

AssigneeSGS-Thomson Microelectronics S.A.

InventorsLaura Pennino, Rinaldo Poluzzi, Massimo Mancuso, Gianguido Rizzotto, Federico Travaglia

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Abstract

A filter performs a reduction of pulsed noise in video images in accordance with fuzzy logic. An interface circuit of the filter receives consecutive digital signals in time corresponding to the video images and generates an image window having a digital signal to be processed at the center. The filter also has a comparator block, a plurality of digital subtractors, and a memory circuit connected in cascade to the comparator block. The filter also has a filtering circuit that organizes values of digital signals of the video image, and an arithmetic block that performs a switch between the digital signal to be processed and the output of the filtering circuit on the basis of the values taken by the parameter.

Claims26

Dependent claims

A filter for reducing pulsed noise in an image by using fuzzy logic, the filter comprising:

an interface circuit, having an input that receives a plurality of digital signals of the image that are consecutive in time including a digital signal to be processed, and an output that provides an image window having the digital signal to be processed at a center of the image window;
a plurality of subtractors, each having a first input that receives the digital signal to be processed, a second input that receives a respective one of the plurality of digital signals, and an output that provides a difference signal that represents a difference between the first input and the second input;
a comparator block, having a plurality of inputs each coupled to the output of one of the plurality of subtractors, and an output that provides a result of a comparison performed on the plurality of differences;
a memory circuit, coupled to the output of the comparator block, that stores values of a fuzzy logic parameter, an output that provides a selected one of the values of the fuzzy logic parameter based upon the result output from the comparator block;
a filtering circuit, having a plurality of inputs that each receives one of a group of the plurality of digital signals, and an output that provides one of the plurality of digital signals based upon an organization of the plurality of digital signals received at the plurality of inputs of the filtering circuit;
and
an arithmetic block, having a first input coupled to the output of the memory circuit, and a second input that receives the digital signal to be processed, a third input coupled to the output of the filtering circuit, the arithmetic block performing a switch between the digital signal to be processed and the output of the filtering circuit based upon the selected value of the fuzzy logic parameter.

4 more elements

Dependencies are inferred from the claim text.