System and method for scaling images and reducing flicker in interlaced television images converted from non-interlaced computer graphics data

A flicker reduction system for reducing flicker in non-interlaced images converted to interlaced images, comprising:

• a flicker reduction filter receiving image data representative of pixel values within a single image, said flicker reduction filter having at least two selectable filters with each filter providing a different frequency response for said flicker reduction filter;
• and
• filter selection circuitry receiving image data representative of pixel values from at least two lines within said single image and having a filter selection signal as an output, said filter selection signal being dependent upon an analysis of pixel values from at least two lines of said single image and being applied to said flicker reduction filter to adaptively select from among said at least two selectable filters to process said image data within said single image;
• wherein said at least two filters include a first filter for portions of an image having sharp changes between adjacent pixel values, and a second filter for portions of an image having smooth changes between adjacent pixel values.

A flicker reduction system for reducing flicker in non-interlaced images converted to interlaced images, comprising:

• a flicker reduction filter receiving image data representative of pixel values from at least two lines of an image, said flicker reduction filter having at least two selectable filters with each filter providing a different frequency response for said flicker reduction filter;
• and
• filter selection circuitry receiving image data representative of pixel values from at least two lines of said image and having a filter selection signal as an output, said filter selection signal being dependent upon said image data and being applied to said flicker reduction filter to select one of said filters;
• wherein said filter selection circuitry provides said filter selection signal on a per-pixel basis to adaptively select a set of filter parameters on a per-pixel basis.

A method for reducing flicker in non-interlaced images converted to interlaced images, comprising:

• receiving image data representative of pixel values within a single image;
• providing a flicker reduction filter having at least two selectable filters with each filter providing a different frequency response for said flicker reduction filter, wherein said at least two filters include a first filter for portions of an image having sharp changes between adjacent pixel values, and a second filter for portions of an image having smooth changes between adjacent pixel values;
• adaptively selecting from among said at least two selectable filters based upon an analysis of pixel values from at least two lines of said single image;
• and
• processing said image data within said single image with said flicker reduction filter to produce output pixel data that is dependent upon said adaptive filter selection.

A method for reducing flicker in non-interlaced images converted to interlaced images, comprising:

• receiving image data representative of pixel values from at least two lines of an image;
• providing a flicker reduction filter having at least two selectable filters with each filter providing a different frequency response for said flicker reduction filter;
• and
• selecting one of said at least two selectable filters based upon a comparison of said pixel values;
• wherein said providing step comprises providing a flicker reduction filter having four sets of selectable filter parameters to provide four selectable filters.

A scaling system for converting image data to a desired output resolution, comprising:

• a scaling block having pixel values for an image as an input and at least two sets of selectable scaling coefficients defining scaled output values, said at least two sets of selectable scaling coefficients comprising a first set that provides a linear interpolation of pixel values and a second set that provides a duplication of pixel values;
• and
• coefficient selection circuitry selecting from among said at least two sets of selectable scaling coefficients for said pixel values within said image depending upon a difference between values for at least two adjacent of said pixel values;
• wherein said first set of linear interpolation coefficients are selected if said difference is higher than a threshold amount and said second set of pixel duplication coefficients are selected if said difference is lower than a threshold amount.

A scaling system for converting image data to a desired output resolution, comprising:

• a scaling block having pixel values as an input and at least two sets of selectable scaling coefficients defining a scaled output value;
• coefficient selection circuitry selecting one of said at least two sets of selectable scaling coefficients depending upon at least one condition related to said pixel values;
• and
• wherein said image data is computer graphics data and said desired output resolution is based upon a television input format.

A method for scaling image data to a desired output resolution, comprising:

• receiving pixel values for an image;
• providing a scaling block having at least two sets of selectable scaling coefficients, said at least two sets of selectable scaling coefficients comprising a first set that provides a linear interpolation of pixel values and a second set that provides a duplication of pixel values;
• analyzing said pixel values;
• selecting from among said at least two sets of selectable scaling coefficients for said pixel values depending upon a difference between values for at least two adjacent of said pixel values;
• selecting said first set of linear interpolation coefficients if said difference is higher than a threshold amount and selecting said second set of pixel duplication coefficients if said difference is lower than a threshold amount;
• and
• applying said selected set of scaling coefficients through said scaling block to generate conditionally scaled output pixel value.

A method for scaling image data to a desired output resolution, comprising:

• receiving pixel values from an image;
• providing a scaling block having at least two sets of selectable scaling coefficients;
• analyzing said pixel values;
• selecting one of said sets of selectable scaling coefficients for said scaling block depending upon a condition related to said pixel values;
• and
• applying said selected set of scaling coefficients through said scaling block to generate a conditionally scaled output value;
• and
• generating an output control signal for each line of pixel values to identify valid and invalid lines;
• wherein said generating step includes identifying even frames in odd lines and odd frames in even lines as invalid as an interlacing mechanism.

A graphics processing system for use in converting computer formatted images into television formatted images, comprising:

• an input interface having computer graphics data as an input;
• conditional scaling circuitry coupled to said input interface to receive said computer graphics data and having conditionally scaled image data as an output, said conditional scaling circuitry having a conditionally applied scaling value dependent upon adjacent pixel values within an image;
• an adaptive flicker reduction filter having said conditionally scaled image data as an input and flicker reduced image data as an output, said flicker reduction filter having at least two sets of selectable filter parameters dependent upon conditions related to values of vertically and horizontally adjacent pixel values;
• a rate converter having said flicker reduced image data as an input and having line rate adjusted data as an output, said line rate adjusted data being substantially compatible with a line rate for a desired television format;
• and
• a television output interface having said line rate adjusted data as an input and having television output data as an output, said television output data being substantially compatible with said desired television format.

A personal computer system providing an image output compatible with a television format, comprising:

• a central processing unit, a memory, an input device, and a storage device connected to each other through an internal bus;
• and
• a graphics processing system connected to said internal bus converting non-interlaced computer graphics data to a desired interlaced television format, said graphics processing system including:
• conditional scaling circuitry conditionally applying a scaling value dependent upon conditions related to pixel values within an image, and
• adaptive flicker reduction circuitry applying one set of at least two selectable sets of filter parameters dependent upon two-dimensional conditions related to pixel values within said image.

A method for converting computer formatted images into television formatted images for graphics processing, comprising:

• receiving computer graphics data representative of an image;
• applying a scaling factor to said computer graphics data conditioned upon adjacent pixel values within said image;
• applying a flicker reduction filter to said computer graphics data with filter parameters dependent upon values of vertically and horizontally adjacent pixel values within said image;
• and
• outputting converted image data in said desired television format.