US5818972A — Method and apparatus for enhancing images using h…

Claim 1

Independent Claim 139 words

A system for enhancing digitized image signals, comprising: an analysis filter for filtering the digitized image signals to produce first frequency band signals; a point operator responsive to first frequency band signals for generating noise reduction signals and image sharpening signals; a synthesis filter that filters the noise reduction signals and image sharpening signals to produce noise reduction helper signals and image sharpening helper signals, the synthesis filter shaping artifacts introduced by nonlinearities associated with the point operator to a desired pattern, and the combination of analysis and synthesis filtering resulting in at least one of smoothing along the edge and sharpening orthogonal to the edge of the image signal; and a summing node by which the noise reduction helper signals, the image signal enhancement signals and the digitized image signals are combined to yield enhanced digitized image signals.

Claim 2

Independent Claim 139 words

A system for enhancing digitized image signals, comprising: an analysis filter for filtering the digitized image signals to produce first frequency band signals; a point operator responsive to first frequency band signals for generating noise reduction signals and image sharpening signals; a synthesis filter that filters the noise reduction signals and image sharpening signals to produce noise reduction helper signals and image sharpening helper signals, the synthesis filter shaping artifacts introduced by nonlinearities associated with the point operator to a desired pattern, and the combination of analysis and synthesis filtering resulting in at least one of smoothing along the edge and sharpening orthogonal to the edge of the image signal; and a summing node by which the noise reduction helper signals, the image signal enhancement signals and the digitized image signals are combined to yield enhanced digitized image signals.

Claim 3

Dependent Claim 52 words

The system of claim 1 wherein the point operator is responsive to first frequency band signals having absolute amplitudes less than a predetermined threshold for generating negative noise reduction signals and responsive to first frequency band signals having absolute amplitudes greater than the predetermined threshold for generating positive image signal enhancement signals.

Claim 4

Independent Claim 187 words

A system for enhancing a digitized image signal, comprising: an analysis filter that filters the digitized image signal to produce a first frequency band signal; a point operator, responsive to the first frequency band signal, that provides a modified signal, the point operator including a non-linear characteristic to produce the modified signal, the non-linear characteristic having a first region, corresponding to low amplitude first frequency band signals, with a first predetermined negative slope, and further having a second region, corresponding to higher amplitude first frequency band signals with an amplitude higher than the low amplitude first frequency band signals, the second region having a positive slope; a synthesis filter that filters the modified signal to produce a helper signal, the synthesis filter shaping artifacts introduced by non-linearities associated with the point operator to a desired pattern, and the combination of analysis and synthesis filtering resulting in at least one of smoothing along the edge and sharpening orthogonal to the edge of the image signal; and a summing node by which the helper signal and the digitized image signal are summed to yield an enhanced digitized image signal.

Claim 5

Independent Claim 187 words

A system for enhancing a digitized image signal, comprising: an analysis filter that filters the digitized image signal to produce a first frequency band signal; a point operator, responsive to the first frequency band signal, that provides a modified signal, the point operator including a non-linear characteristic to produce the modified signal, the non-linear characteristic having a first region, corresponding to low amplitude first frequency band signals, with a first predetermined negative slope, and further having a second region, corresponding to higher amplitude first frequency band signals with an amplitude higher than the low amplitude first frequency band signals, the second region having a positive slope; a synthesis filter that filters the modified signal to produce a helper signal, the synthesis filter shaping artifacts introduced by non-linearities associated with the point operator to a desired pattern, and the combination of analysis and synthesis filtering resulting in at least one of smoothing along the edge and sharpening orthogonal to the edge of the image signal; and a summing node by which the helper signal and the digitized image signal are summed to yield an enhanced digitized image signal.

Claim 6

Dependent Claim 98 words

The system of claim 1 further comprising: at least one additional analysis filter that filters the digitized image signal to produce at least one additional corresponding frequency band signal; at least one additional point operator, responsive to the additional corresponding frequency band signal, that provides at least one additional modified signal; at least one additional synthesis filter that filters the additional modified signal to produce at least one additional helper signal; and wherein the additional helper signal is summed at the summing node with the image signal and the helper signal to yield the enhanced digitized image signal.

Claim 7

Dependent Claim 51 words

The system of claim 1 wherein the image signal is a two dimensional signal and wherein the analysis filter and the synthesis filter have predetermined impulse responses, each impulse response having non-zero weight diagonal coefficients across a first diagonal and zero weight coefficients across a second diagonal of the impulse response.

Claim 8

Dependent Claim 40 words

The system of claim 1 wherein the point operator is determined in accordance with impulse responses of the analysis and synthesis filters, such that a combination of the analysis filter the point operator, and the synthesis filter suppresses white noise.

Claim 9

Dependent Claim 57 words

The system of claim 3 wherein the point operator includes a LUT for providing the modified signals in response to the frequency band signal, and wherein the nonlinear characteristic includes a third region for frequency band signals having an amplitude higher than said higher amplitude first frequency signals, wherein the third region has a second negative slope.

Claim 10

Dependent Claim 29 words

The system of claim 1 wherein the analysis filter, the point operator, the synthesis filter, and the summing node are implemented on a general purpose computer as software routines.

Claim 11

Dependent Claim 34 words

The system of claim 3 wherein the digitized input signal is a real-time video signal according to a predefined signal standard and wherein the enhanced digitized image signal is in the predefined signal standard.

Claim 12

Dependent Claim 15 words

The system of claim 3 wherein the first frequency band is a high frequency band.

Claim 13

Independent Claim 131 words

A method of enhancing digitized image signals, the method comprising the steps of: a) analysis filtering the digitized image signal, to produce first frequency band signals; b) generating noise reduction signals and image sharpening signals in response to the first frequency band signals; c) synthesis filtering the noise reduction signals and image sharpening signals to shape artifacts introduced by non-linearities associated with the point operator to a desired pattern and produce noise reduction helper signals and image sharpening helper signals. the combination of analysis and synthesis filtering resulting in at least one of smoothing along the edge and sharpening orthogonal to the edge of the image signal; and d) combining the noise reduction helper signals, the image signal enhancement signals and the digitized image signals to yield enhanced digitized image signals.

Claim 14

Independent Claim 131 words

A method of enhancing digitized image signals, the method comprising the steps of: a) analysis filtering the digitized image signal, to produce first frequency band signals; b) generating noise reduction signals and image sharpening signals in response to the first frequency band signals; c) synthesis filtering the noise reduction signals and image sharpening signals to shape artifacts introduced by non-linearities associated with the point operator to a desired pattern and produce noise reduction helper signals and image sharpening helper signals. the combination of analysis and synthesis filtering resulting in at least one of smoothing along the edge and sharpening orthogonal to the edge of the image signal; and d) combining the noise reduction helper signals, the image signal enhancement signals and the digitized image signals to yield enhanced digitized image signals.

Claim 15

Independent Claim 149 words

A method for enhancing a digitized image signal, the method comprising the steps of: a) analysis filtering the digitized image signal to produce a first frequency band signal; b) modifying the first frequency band signal in accordance with a non-linear characteristic to produce a modified signal, the non-linear characteristic having a first region with a negative slope for low amplitude first frequency band signals and a second region with a positive slope for higher amplitude frequency band signals; c) synthesis filtering the modified signal to shape artifacts introduced by nonlinearities associated with the point operator to a desired pattern and produce a helper signal, the combination of analysis and synthesis filtering resulting in at least one of smoothing along the edge and sharpening orthogonal to the edge of the image signal; and d) adding the helper signal and the digitized image signal to yield an enhanced digitized image signal.

Claim 16

Independent Claim 149 words

A method for enhancing a digitized image signal, the method comprising the steps of: a) analysis filtering the digitized image signal to produce a first frequency band signal; b) modifying the first frequency band signal in accordance with a non-linear characteristic to produce a modified signal, the non-linear characteristic having a first region with a negative slope for low amplitude first frequency band signals and a second region with a positive slope for higher amplitude frequency band signals; c) synthesis filtering the modified signal to shape artifacts introduced by nonlinearities associated with the point operator to a desired pattern and produce a helper signal, the combination of analysis and synthesis filtering resulting in at least one of smoothing along the edge and sharpening orthogonal to the edge of the image signal; and d) adding the helper signal and the digitized image signal to yield an enhanced digitized image signal.

Claim 17

Dependent Claim 88 words

The method of claim 11 further comprising the steps of: e) analysis filtering the digitized image signal to produce at least one additional frequency band signal; f) modifying the additional frequency band signal to produce at least one additional modified signal therefrom; g) synthesis filtering the additional modified signal to produce at least one additional helper signal; and wherein step D further includes the step of d1) adding the additional helper signal to the image signal and to the helper signal to yield the enhanced digitized image signal.

Claim 18

Dependent Claim 51 words

The method of claim 11 wherein the image signal is a two dimensional signal and steps a and c perform filtering steps according to predetermined impulse responses, each impulse response having non-zero weight diagonal coefficients across a first diagonal and zero weight coefficients across a second diagonal of the impulse response.

Claim 19

Dependent Claim 43 words

The method of claim 12 wherein the first predetermined negative slope is determined in accordance with the impulse responses of the analysis and synthesis filters, such that a combination of the analysis filter, the point operator, and the synthesis filter suppresses white noise.

Claim 20

Dependent Claim 57 words

The method of claim 12 wherein step b includes accessing a LUT that provides the modified signals in response to the frequency band signal, and wherein the non-linear characteristic includes a third region for frequency band signals having an amplitude higher than said higher amplitude first frequency signals, wherein the third region has a second negative slope.

Claim 21

Dependent Claim 18 words

The method of claim 13 wherein steps (a)-(d) are executed on a general purpose computer as software routines.

Claim 22

Dependent Claim 34 words

The method of claim 13 wherein the digitized input signal is a real-time video signal according to a predefined signal standard and wherein the enhanced digitized image signal is in the predefined signal standard.

Claim 23

Dependent Claim 15 words

The method of claim 13 wherein the first frequency band is a high frequency band.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	2001-10-05	2002-04-06	2002-10-06	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2005-10-05	2006-04-06	2006-10-06	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2009-10-05	2010-04-06	2010-10-06	$7700.00	Window Closed / Lapsed

Method and apparatus for enhancing images using helper signals

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