US 6,600,495 B1 · Image interpolation and decimation using a continuously variable delay filter and combined with a polyphase filter

Abstract

A filter structure is provided that facilitates the use of the filter as either a continuous delay Farrow filter or a selectable delay polyphase filter. The less complex polyphase filter is used when the desired scale substantially corresponds to a defined phase of the polyphase filter, or when time or power is not available to achieve the desired scale exactly; otherwise, the continuous delay Farrow filter is used. By providing an ability to switch to a continuous delay, the number of stages of the polyphase filter can be reduced. Additionally, an inversion of a Farrow filter is presented that provides for a continuous delay decimation filter with substantially reduced computational complexity compared to a direct embodiment of a Farrow filter. This inverted filter is also configurable as a polyphase filter, to provide selectable scale-resolution capabilities.

Claims20

Dependent claims

An image display system comprising:

at least one configurable filter, and
at least one controllable switch that is arranged to:
configure said at least one configurable filter as a polyphase filter when said at least one controllable switch is controlled to a first state, and
configure said at least one configurable filter as a Farrow filter when said at least one controllable switch is controlled to a second state.

1 more element

A filter for producing an output sample from a sequence of input samples and a sequence of delays corresponding to a temporal relationship between the output sample and the input samples, the filter comprising:

a plurality of filter stages,
a plurality of multipliers, and
a plurality of adders, wherein,
the plurality of multipliers are arranged in series, wherein
a first multiplier in the series of multipliers receives each input of the sequence of input samples, and
each multiplier of the plurality of multipliers receives each delay of the sequence of delays;
the plurality of filter stages are arranged in parallel, each stage having an input and an output, wherein
a first stage of the plurality of filter stages receives as input each input of the sequence of input samples, and
each subsequent stage of the plurality of filter stages receives as input a corresponding output of each multiplier of the plurality of multipliers;
and
the plurality of adders are arranged in series, wherein
a first adder in the series of adders receives the output of the first stage of the plurality of filter stages and the output of a second stage of the plurality of filter stages, and
each subsequent adder in the series of adders receives the corresponding output of each subsequent stage of the plurality of filter stages wherein
each stage of the plurality of filter stages comprises a plurality of accumulators, wherein:
each accumulator of the plurality of accumulators being configured to:
multiply the input to the stage by a corresponding coefficient to form a product term, and
accumulate an accumulated sum of the product term corresponding to each input sample of the sequence of input samples;
and
the output of each stage corresponds to a sum of the accumulated sum of each accumulator wherein
the coefficient of each accumulator corresponds to an estimation coefficient of a Farrow filter.

17 more elements

Dependencies are inferred from the claim text.

Image interpolation and decimation using a continuously variable delay filter and combined with a polyphase filter

Life of this patent

Image interpolation and decimation using a continuously variable delay filter and combined with a polyphase filter

Life of this patent

Abstract

Claims20