Filter system and method for efficiently suppressing noise and improving edge definition in a digitized image

Claim 1

A method for efficiently improving a digitized image defined by pixel values, comprising the steps of: supplying a base line of an image, which comprises an image data array, to a plurality of filters, said plurality of filters including a preemphasis filter, a vector smooth filter, and an area smooth filter; processing and image data array concurrently in said plurality of filters to derive a corresponding plurality of modified image arrays, the preemphasis filter processing the image data array to enhance edges in the image data array, the vector smooth filter processing the image data array to smooth the image data array while emphasizing certain linear features contained within the image data array, the area smooth filter processing the image data array to adjust values of pixels surrounding a target pixel of the image data array such that the pixel values of the pixels surrounding the target pixel are provided with values that are closer in value to the pixel value of the target pixel; and combining said image data arrays to drive an improved image data array.

Claim 2

A method for efficiently improving a digitized image defined by pixel values, comprising the steps of: supplying a base line of an image, which comprises an image data array, to a plurality of filters, said plurality of filters including a preemphasis filter, a vector smooth filter, and an area smooth filter; processing and image data array concurrently in said plurality of filters to derive a corresponding plurality of modified image arrays, the preemphasis filter processing the image data array to enhance edges in the image data array, the vector smooth filter processing the image data array to smooth the image data array while emphasizing certain linear features contained within the image data array, the area smooth filter processing the image data array to adjust values of pixels surrounding a target pixel of the image data array such that the pixel values of the pixels surrounding the target pixel are provided with values that are closer in value to the pixel value of the target pixel; and combining said image data arrays to drive an improved image data array.

Claim 10

A system for efficiently improving a digitized image defined by pixel values, comprising: a plurality of filters, each said filter configured to receive an image data array and to modify said image data array to derive a respective modified image data array for each of said plurality of filters, said plurality of filters including a preemphasis filter, a vector smooth filter, and an area smooth filter, the preemphasis filter enhancing edges contained in said image data array, said vector smooth filter performing a smoothing function while emphasizing linear features in said image data array, said area smooth filter adjusting pixel values of pixels surrounding a target pixel such that the pixel values of the pixels surrounding the target pixel are provided with pixel values that are closer to the pixel value of the target pixel; a plurality of gain control mechanisms associated respectively with said filters, each said gain control mechanism adapted to modify a respective modified image data array based upon a gain factor allocated to said gain control mechanism; and an assimilation mechanism in communication with said gain control mechanisms, said assimilation mechanism receiving said modified image data arrays from said gain control mechanisms and combining said modified image data arrays to derive an improved image data array.

Claim 11

A system for efficiently improving a digitized image defined by pixel values, comprising: a plurality of filters, each said filter configured to receive an image data array and to modify said image data array to derive a respective modified image data array for each of said plurality of filters, said plurality of filters including a preemphasis filter, a vector smooth filter, and an area smooth filter, the preemphasis filter enhancing edges contained in said image data array, said vector smooth filter performing a smoothing function while emphasizing linear features in said image data array, said area smooth filter adjusting pixel values of pixels surrounding a target pixel such that the pixel values of the pixels surrounding the target pixel are provided with pixel values that are closer to the pixel value of the target pixel; a plurality of gain control mechanisms associated respectively with said filters, each said gain control mechanism adapted to modify a respective modified image data array based upon a gain factor allocated to said gain control mechanism; and an assimilation mechanism in communication with said gain control mechanisms, said assimilation mechanism receiving said modified image data arrays from said gain control mechanisms and combining said modified image data arrays to derive an improved image data array.

Claim 18

A system for efficiently improving a digitized image defined by pixel values, comprising: (a) a statistical noise determination mechanism adapted to determine a baseline noise level from said image; (b) means for communicating an image data array from said image to first, second, and third branches which are in parallel, each said branch configured to modify said image data array to derive a respective modified image data array; (c) said first branch having a preemphasis filter, said preemphasis filter adapted to modify a pixel value along a transition boundary of said image data array as a function of the difference between said pixel value and the mean pixel value of pixels within a predefined window surrounding said pixel value, a predetermined enhancement factor, and a predetermined relaxation factor; (d) said second branch having a vector smooth filter, said vector smooth filter comprising: (1) means for determining a mean of pixel values for pixels arranged along a line through a center pixel at a center of said image data array; (2) means for determining a new pixel value of said center pixel, based on an old pixel value for said center pixel and said mean of pixel values for pixels arranged along said line; and (3) means for replacing said old pixel value with said new pixel value; (e) said third branch having an area smooth filter followed by a high enhance filter, said area smooth filter comprising: (1) means for selecting a first pixel value to be enhanced in said image data array; (2) means for sampling a select group of pixel values within a predefined window surrounding said selected pixel value; (3) means for generating an enhancement argument based upon the number of pixels in said predefined window surrounding said pixel value of a greater value than said selected pixel value, said baseline noise level of said image, and a smoothness factor; and (4) means for modifying said selected pixel value based upon said enhancement argument to reduce local variances in pixel values due to noise; said high enhance filter adapted to add noise to said image data array so that high frequency, low amplitude information is restored in said image data array; a plurality of user adjustable gain control mechanisms associated respectively with said branches, each said gain control mechanism adapted to independently modify said image data array based upon a gain factor allocated to said gain control mechanism, wherein each said user adjustable gain control mechanism associated by said allocation with each of said branches operates independently of any other of said branches not associated by said allocation therewith; and an assimilation mechanism in communication with said gain control mechanisms, said assimilation mechanism for combining said modified image data arrays from said gain control mechanisms to derive an improved image data array.

Claim 19

A system for efficiently improving a digitized image defined by pixel values, comprising: (a) a statistical noise determination mechanism adapted to determine a baseline noise level from said image; (b) means for communicating an image data array from said image to first, second, and third branches which are in parallel, each said branch configured to modify said image data array to derive a respective modified image data array; (c) said first branch having a preemphasis filter, said preemphasis filter adapted to modify a pixel value along a transition boundary of said image data array as a function of the difference between said pixel value and the mean pixel value of pixels within a predefined window surrounding said pixel value, a predetermined enhancement factor, and a predetermined relaxation factor; (d) said second branch having a vector smooth filter, said vector smooth filter comprising: (1) means for determining a mean of pixel values for pixels arranged along a line through a center pixel at a center of said image data array; (2) means for determining a new pixel value of said center pixel, based on an old pixel value for said center pixel and said mean of pixel values for pixels arranged along said line; and (3) means for replacing said old pixel value with said new pixel value; (e) said third branch having an area smooth filter followed by a high enhance filter, said area smooth filter comprising: (1) means for selecting a first pixel value to be enhanced in said image data array; (2) means for sampling a select group of pixel values within a predefined window surrounding said selected pixel value; (3) means for generating an enhancement argument based upon the number of pixels in said predefined window surrounding said pixel value of a greater value than said selected pixel value, said baseline noise level of said image, and a smoothness factor; and (4) means for modifying said selected pixel value based upon said enhancement argument to reduce local variances in pixel values due to noise; said high enhance filter adapted to add noise to said image data array so that high frequency, low amplitude information is restored in said image data array; a plurality of user adjustable gain control mechanisms associated respectively with said branches, each said gain control mechanism adapted to independently modify said image data array based upon a gain factor allocated to said gain control mechanism, wherein each said user adjustable gain control mechanism associated by said allocation with each of said branches operates independently of any other of said branches not associated by said allocation therewith; and an assimilation mechanism in communication with said gain control mechanisms, said assimilation mechanism for combining said modified image data arrays from said gain control mechanisms to derive an improved image data array.