US 5,589,890 AGranted

Filter architecture, particularly for video applications

AssigneesSGS-Thomson Microelectronics S.A., Consorzio per la Ricerca sulla Microelettronica nel Mezzogiorno

InventorsMassimo Mancuso, Rinaldo Poluzzi, Gianguido Rizzotto

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Abstract

A filter architecture particularly for video applications, includes a filter section for separating high pass and low pass components from a video input signal conveying a video image, a brilliance estimating section for determining a mean brilliance value for each of a plurality of sections into which the video image is divided, first and second image characteristic adjusting sections for modifying the high pass and low pass components in response to the mean brilliance values, and a summing section for combining the modified high pass and low pass components to generate a filtered video signal. The first and second image characteristic adjusting sections operate using Fuzzy Logic which enables the filter architecture to effectively adjust contrast and brightness in the video image over a wide range of image brightness values.

Claims41

Dependent claims

A digital signal filter for video images, comprising:

a timing circuit having first, second, and third outputs for providing synchronism command signals;
a filter circuit having a first input coupled to an input of the digital signal filter, and a second input coupled to the first output of the timing circuit, said filter circuit including means for separating from an input signal high frequency components and low frequency components and for generating first and second outputs for the high and low frequency components, respectively;
a brilliance estimation circuit having a first input coupled to said input of the digital signal filter, and at least second, third, and fourth inputs respectively coupled to the first, second, and third outputs of the timing circuit, said brilliance estimation circuit having means for measuring and memorizing brilliance values associated with at least one image section:
a first image characteristic adjusting circuit for a first image characteristic, operated using fuzzy logic, having a first input coupled to said input of the digital signal filter, a second input coupled to said first output of the filter circuit, and a third input coupled to at least one output of said brilliance estimation circuit;
and
a second image characteristic adjusting circuit for at least a second image characteristic, operated in a manner based on Fuzzy logic, having a first input coupled to said second output of the filter circuit and a second input coupled to said at least one output of the brilliance estimation circuit.

3 more elements

A video filter for adjusting an input signal for a video image, comprising:

a brilliance estimation circuit that generates, in response to the input signal, a mean brilliance signal for each of a plurality of sections of the video image;
a filter circuit that separates the input signal into a high-pass filtered component and a low-pass filtered component;
a first image characteristic adjusting circuit that applies Fuzzy Logic operations to generate, in response to the mean brilliance signal and the high-pass filtered component, a modified high-pass filtered component;
a second image characteristic adjusting circuit that applies Fuzzy Logic operations to generate, in response to the mean brilliance signal and the low-pass filtered component, a modified low-pass filtered component;
and
a summing circuit that combines the modified high-pass and low-pass filtered components to generate an adjusted video signal.

3 more elements

Dependencies are inferred from the claim text.