Method and system for filter type approximation in computer graphics processing

A method of computing a characteristic value of an output pixel based on characteristic values of a plurality of input pixels, the method comprising the computer-implemented steps of:

• obtaining a filter response curve adjustment value based on a distance interval between coordinates of the output pixel and coordinates of a selected input pixel;
• computing a normalized filter response curve input value based on the distance interval and the filter response curve adjustment value;
• obtaining characteristic values at a plurality of input pixels;
• and
• computing a linearly interpolated value for the characteristic value of the output pixel based on the characteristic values of the plurality of input pixels and the normalized filter response curve input value;
• computing coordinates for the output pixel;
• and
• computing the distance interval between coordinates of the output pixel and coordinates of the selected input pixel.

A method of computing a characteristic value of an output pixel based on characteristic values of a plurality of input pixels, the method comprising the computer-implemented steps of:

• obtaining a filter response curve adjustment value based on a distance interval between coordinates of the output pixel and coordinates of a selected input pixel;
• computing a normalized filter response curve input value based on the distance interval and the filter response curve adjustment value;
• obtaining characteristic values at a plurality of input pixels;
• and
• computing a linearly interpolated value for the characteristic value of the output pixel based on the characteristic values of the plurality of input pixels and the normalized filter response curve input value, wherein the filter response curve adjustment value is retrieved from a lookup table based on the distance interval, and wherein the lookup table contains a difference between a value, at a particular coordinate, of a filter function between a plurality of input pixels and a value of a linear equation between a plurality of input pixels.

A data processing system for computing a characteristic value of an output pixel based on characteristic values of a plurality of input pixels, the data processing system comprising:

• first obtaining means for obtaining a filter response curve adjustment value based on a distance interval between coordinates of the output pixel and coordinates of a selected input pixel;
• first computing means computing means for computing a normalized filter response curve input value based on the distance interval and the filter response curve adjustment value;
• second obtaining means for obtaining characteristic values at a plurality of input pixels;
• second computing means for computing a linearly interpolated value for the characteristic value of the output pixel based on the characteristic values of the plurality of input pixels;
• and
• first adjusting means for adjusting the linearly interpolated value by an error term based on the normalized filter response curve input value.

A data processing system for computing a characteristic value of an output pixel based on characteristic values of a plurality of input pixels, the data processing system comprising:

• first obtaining means for obtaining a filter response curve adjustment value based on a distance interval between coordinates of the output pixel and coordinates of a selected input pixel;
• first computing means computing means for computing a normalized filter response curve input value based on the distance interval and the filter response curve adjustment value;
• second obtaining means for obtaining characteristic values at a plurality of input pixels;
• and
• second computing means for computing a linearly interpolated value for the characteristic value of the output pixel based on the characteristic values of the plurality of input pixels and the normalized filter response curve input value;
• third computing means for computing coordinates for the output pixel;
• and
• fourth computing means for computing the distance interval between coordinates of the output pixel and coordinates of the selected input pixel.

A data processing system for computing a characteristic value of an output pixel based on characteristic values of a plurality of input pixels, the data processing system comprising:

• first obtaining means for obtaining a filter response curve adjustment value based on a distance interval between coordinates of the output pixel and coordinates of a selected input pixel;
• first computing means computing means for computing a normalized filter response curve input value based on the distance interval and the filter response curve adjustment value;
• second obtaining means for obtaining characteristic values at a plurality of input pixels;
• and
• second computing means for computing a linearly interpolated value for the characteristic value of the output pixel based on the characteristic values of the plurality of input pixels and the normalized filter response curve input value, wherein the filter response curve adjustment value is retrieved from a lookup table based on the distance interval, and wherein the lookup table contains a difference between a value, at a particular coordinate, of a filter function between a plurality of input pixels and a value of a linear equation between a plurality of input pixels.

A computer program product in a computer-readable medium for use in a data processing system for computing a characteristic value of an output pixel based on characteristic values of a plurality of input pixels, the computer program product comprising:

• first instructions for obtaining a filter response curve adjustment value based on a distance interval between coordinates of the output pixel and coordinates of a selected input pixel;
• second instructions for computing a normalized filter response curve input value based on the distance interval and the filter response curve adjustment value;
• third instructions for obtaining characteristic values at a plurality of input pixels;
• fourth instructions for computing a linearly interpolated value for the characteristic value of the output pixel based on the characteristic values of the plurality of input pixels;
• and
• fifth instructions for adjusting the linearly interpolated value by an error term based on the normalized filter response curve input value.

A computer program product in a computer-readable medium for use in a data processing system for computing a characteristic value of an output pixel based on characteristic values of a plurality of input pixels, the computer program product comprising:

• first instructions for obtaining a filter response curve adjustment value based on a distance interval between coordinates of the output pixel and coordinates of a selected input pixel;
• second instructions for computing a normalized filter response curve input value based on the distance interval and the filter response curve adjustment value;
• third instructions for obtaining characteristic values at a plurality of input pixels;
• and
• fourth instructions for computing a linearly interpolated value for the characteristic value of the output pixel based on the characteristic values of the plurality of input pixels and the normalized filter response curve input value;
• instructions for computing coordinates for the output pixel;
• and
• instructions for computing the distance interval between coordinates of the output pixel and coordinates of the selected input pixel.

A computer program product in a computer-readable medium for use in a data processing system for computing a characteristic value of an output pixel based on characteristic values of a plurality of input pixels, the computer program product comprising:

• first instructions for obtaining a filter response curve adjustment value based on a distance interval between coordinates of the output pixel and coordinates of a selected input pixel;
• second instructions for computing a normalized filter response curve input value based on the distance interval and the filter response curve adjustment value;
• third instructions for obtaining characteristic values at a plurality of input pixels;
• and
• fourth instructions for computing a linearly interpolated value for the characteristic value of the output pixel based on the characteristic values of the plurality of input pixels and the normalized filter response curve input value, wherein the filter response curve adjustment value is retrieved from a lookup table based on the distance interval, and wherein the lookup table contains a difference between a value, at a particular coordinate, of a filter function between a plurality of input pixels and a value of a linear equation between a plurality of input pixels.