US 6,587,117 B1 · Apparatus and method for adaptive transformation of fractional pixel coordinates for calculating color values

Abstract

A system and method for adaptive interpolation of a color value for a destination pixel from color values of adjacent source pixels and the destination pixel's coordinate values. An adaptive color value interpolation circuit includes look-up-tables (LUTs) to store a plurality of values for each of the destination pixel's coordinates. Each of the LUTs provide to an interpolation circuit a selected one of the plurality of stored values in the LUTs according to the respective coordinate value. The interpolation circuit also receives the color values of the adjacent pixels. The interpolation circuit calculates the pixel's interpolated color value by weighting the color values of the adjacent pixels according to the selected values from the first and second LUTs. Instead of determining the pixel's color value by directly applying the destination pixel's coordinate values in the color weighting calculation, the pixel's color value is determined from weighting the source pixels' color values according to the stored values provided by the LUTs. Consequently, various interpolation functions may be simulated by the adaptive interpolation circuit by programming the appropriate values in the LUTs for the pixel's respective coordinates.

Claims64

Dependent claims

An adaptive interpolation circuit for calculating an interpolated color value for a pixel, comprising:

first and second look-up-tables (LUTs), each LUT having a plurality of output terminals on which to provide a corresponding plurality of stored values;
first and second data selection circuits, each data selection circuit having a plurality of input terminals coupled to the plurality of output terminals of a respective LUT and an output terminal to selectively provide a selected one of the plurality of stored values from the respective LUT in accordance to a selection value, the first and second data selection circuits coupled to receive first and second coordinate values of the pixel, respectively, as the selection value;
and
an interpolation circuit having first and second input terminals coupled to the output terminal of a respective data selection circuit, the first selection circuit providing a first value f(rU) and the second selection circuit providing a second value f(rV), the interpolation circuit further having additional color input terminals to receive color values Ct0, Ct1, Ct2, and Ct3 from which the interpolated color value is calculated and an output terminal to provide the pixel's interpolated color value, the output value calculated according to the equation Cp=[(1−f(rU))·(1−f(rV))·Ct0]+[f(rU)(1−f(rV))·Ct1]+[(1−f(rU))·f(rV)·Ct2]+[f(rU)·f(rV) Ct3].

1 more element

An adaptive interpolation circuit for calculating an interpolated color value for a pixel having first and second coordinate values from color values Ct0, Ct1, Ct2, and Ct3 of adjacent pixels, the adaptive interpolation circuit comprising:

first and second look-up-tables (LUTs) to store a plurality of values, each LUT having a selection circuit coupled to receive an index value corresponding to a respective coordinate value and an output terminal to provide a selected one of the plurality of stored values according to the received index value, the selection circuit of the first LUT providing a first selected value f(rU) and the selection circuit of the second LUT providing a second selected value f(rV);
and
an interpolation circuit having color input terminals to receive the color values of the adjacent pixels and first and second input terminals coupled to the output terminal of a respective LUT to receive the selected values f(rU) and f(rV), respectively, the interpolation circuit calculating the pixel's interpolated color value from the color values Ct0, Ct1, Ct2, and Ct3 of the adjacent pixels and the selected values from the first and second LUT according to the equation Cp=[(1−f(rU))·(1−f(rV))·Ct0]+[f(rU)(1−f(rV))·Ct1]+[(1−f(rU)) f(rV)·Ct2]+[f(rU)·f(rV)·Ct3].

A graphics processing system, comprising:

a bus interface for coupling to a system bus;
a graphics processor coupled to the bus interface to process graphics data;
address and data busses coupled to the graphics processor to transfer address and graphics data to and from the graphics processor;
display logic coupled to the data bus to drive a display;
and
an adaptive color interpolation circuit coupled to the graphics processor and the display logic to calculate an interpolated color value for a pixel having first and second coordinate values from color values Ct0, Ct1, Ct2, and Ct3 of adjacent pixels, the adaptive color interpolation circuit comprising:
first and second look-up-tables (LUTs) to store a plurality of values, each LUT having a selection circuit coupled to receive an index value corresponding to a respective coordinate value and an output terminal to provide a selected one of the plurality of stored values according to the received index value, the selection circuit of the first LUT providing a first selected value f(rU) and the selection circuit of the second LUT providing a second selected value f(rV);
and
an interpolation circuit having color input terminals to receive the color values of the adjacent pixels and first and second input terminals coupled to the output terminal of a respective LUT to receive the selected values f(rU) and f(rV), respectively, the interpolation circuit calculating the pixel's interpolated color value from the color values Ct0, Ct1, Ct2, and Ct3 of the adjacent pixels and the selected values from the first and second LUT according to the equation Cp=[(1−f(rU))·(1−f(rV))·Ct0]+[f(rU)·(1−f(rV))·Ct1]+[(1+f(rU))·f(rV)·Ct2]+[f(rU)·f(rV)·Ct3].

6 more elements

A computer system, comprising:

a system processor;
a system bus coupled to the system processor;
a system memory coupled to the system bus;
and
a graphics processing system coupled to the system bus, the graphics processing system, comprising:
a bus interface for coupling to the system bus;
a graphics processor coupled to the bus interface to process graphics data;
address and data busses coupled to the graphics processor to transfer address and graphics data to and from the graphics processor;
display logic coupled to the data bus to drive a display;
and
an adaptive color interpolation circuit coupled to the graphics processor and the display logic to calculate an interpolated color value for a pixel having first and second coordinate values from color values Ct0, Ct1, Ct2, and Ct3 of adjacent pixels, the adaptive color interpolation circuit comprising:
first and second look-up-tables (LUTs) to store a plurality of values, each LUT having a selection circuit coupled to receive an index value corresponding to a respective coordinate value and an output terminal to provide a selected one of the plurality of stored values according to the received index value, the selection circuit of the first LUT providing a first selected value f(rU) and the selection circuit of the second LUT providing a selected value f(rV);
and
an interpolation circuit having color input terminals to receive the color values of the adjacent pixels and first and second input terminals coupled to the output terminal of a respective LUT to receive the selected values f(rU) and f(rV), respectively, the interpolation circuit calculating the pixel's interpolated color value from the color values Ct0, Ct1, Ct2, and Ct3 of the adjacent pixels and the selected values from the first and second LUT according to the equation Cp=[(1−f(rU))·(1−f(rV))·Ct0]+[f(rU)·(1−f(rV))·Ct1]+[(1−f(rU))·f(rV)·Ct2]+[f(rU)·f(rV)·Ct3].

11 more elements

first and second look-up-tables (LUTs) to store a plurality of values, each LUT having a selection circuit coupled to receive an index value corresponding to a respective coordinate value and an output terminal to provide a selected one of the plurality of stored values according to the received index value, the selection circuit of the first LUT providing a first selected value f(rU) and the selection circuit of the second LUT providing a second selected value f(rV);
and
a bilinear interpolation circuit receiving the color values Ct0, Ct1, Ct2, and Ct3 and having first and second input terminals coupled to a respective LUT to receive the selected values f(rU) and f(rV), the bilinear interpolation circuit using the first and second selected values f(rU) and f(rV), respectively, in weighting the color values Ct0, Ct1, Ct2, and Ct3 to bilinearly interpolate the interpolated color value for the pixel.

Dependencies are inferred from the claim text.

Apparatus and method for adaptive transformation of fractional pixel coordinates for calculating color values

Life of this patent

Apparatus and method for adaptive transformation of fractional pixel coordinates for calculating color values

Life of this patent

Abstract

Claims64