Method and apparatus for scaling images having a plurality of scan lines of pixel data

Claim 1

A method of scaling images in a digital display system having a central processing unit, and a graphics control circuit including a frame buffer, comprising the steps of: interpolating the pixels of each scan line of pixels to a selected scale using the central processing unit as the scan line is written, replicating in the slow scan direction each interpolated scan line being sent to the frame buffer to a selected scale using circuitry of the graphics control circuit, interpolating scan lines in the slow scan direction utilizing selected scan lines stored in the frame buffer as input scan lines, and replacing existing scan lines which have been selected for interpolation with the interpolated scan lines.

Claim 2

A method of scaling images in a digital display system having a central processing unit, and a graphics control circuit including a frame buffer, comprising the steps of: interpolating the pixels of each scan line of pixels to a selected scale using the central processing unit as the scan line is written, replicating in the slow scan direction each interpolated scan line being sent to the frame buffer to a selected scale using circuitry of the graphics control circuit, interpolating scan lines in the slow scan direction utilizing selected scan lines stored in the frame buffer as input scan lines, and replacing existing scan lines which have been selected for interpolation with the interpolated scan lines.

Claim 7

A method of scaling images in a digital display system having a central processing unit, and a graphics control circuit including a frame buffer, comprising the steps of: interpolating the pixels of each scan line of pixels to a selected scale using the central processing unit as the scan line is written, replicating each interpolated scan line being sent to the frame buffer to a selected scale using circuitry of the graphics control circuit, selectively interpolating scan lines utilizing scan lines stored in the frame buffer as input scan lines, the step beginning by interpolating scan lines containing pixel data which contributes least to replacing scan lines, and proceeding by interpolating scan lines in an increasing order of contribution to replacing scan lines, the step of selectively interpolating scan lines uses a blending circuit to interpolate scan lines, and replacing existing scan lines which have been selected for interpolation with the interpolated scan lines.

Claim 8

A method of scaling images in a digital display system having a central processing unit, and a graphics control circuit including a frame buffer, comprising the steps of: interpolating the pixels of each scan line of pixels to a selected scale using the central processing unit as the scan line is written, replicating each interpolated scan line being sent to the frame buffer to a selected scale using circuitry of the graphics control circuit, selectively interpolating scan lines utilizing scan lines stored in the frame buffer as input scan lines, the step beginning by interpolating scan lines containing pixel data which contributes least to replacing scan lines, and proceeding by interpolating scan lines in an increasing order of contribution to replacing scan lines, the step of selectively interpolating scan lines uses a blending circuit to interpolate scan lines, and replacing existing scan lines which have been selected for interpolation with the interpolated scan lines.

Claim 9

A method of processing a digital input image having a plurality of original scan lines of pixel data into an interpolated digital output image comprising the steps of: interpolating the pixel data in each original scan line of the digital input image to provide from each original scan line a plurality of identical scan lines interpolated in a fast scan direction, storing the interpolated scan lines, calculating a value of weight of each existing stored scan line that may be replaced by a scan line interpolated in a slow scan direction, the weight representing a contribution of an existing scan line to be used in the weighted sum with other scan lines to compute a replacement for the existing scan line, selecting groups of existing scan lines from storage to produce interpolated scan lines in the slow scan direction of the interpolated output image, creating an interpolated scan line for each existing scan line in a selected group as a weighted sum of the existing scan line with another scan line, and writing each interpolated scan line created in place of an existing scan line from each of the groups.

Claim 10

A method of processing a digital input image having a plurality of original scan lines of pixel data into an interpolated digital output image comprising the steps of: interpolating the pixel data in each original scan line of the digital input image to provide from each original scan line a plurality of identical scan lines interpolated in a fast scan direction, storing the interpolated scan lines, calculating a value of weight of each existing stored scan line that may be replaced by a scan line interpolated in a slow scan direction, the weight representing a contribution of an existing scan line to be used in the weighted sum with other scan lines to compute a replacement for the existing scan line, selecting groups of existing scan lines from storage to produce interpolated scan lines in the slow scan direction of the interpolated output image, creating an interpolated scan line for each existing scan line in a selected group as a weighted sum of the existing scan line with another scan line, and writing each interpolated scan line created in place of an existing scan line from each of the groups.

Claim 16

A method of processing a digital input image having a plurality of original scan lines of pixel data into an interpolated digital output image comprising the steps of: interpolating the pixel data in each original scan line of the digital input image to provide from each original scan line a plurality of identical scan lines interpolated in a fast scan direction, storing the interpolated scan lines, calculating a value of weight of each existing stored scan line that may be replaced by a scan line interpolated in a slow scan direction, the weight representing a contribution of an existing scan line to be used in the weighted sum with other scan lines to compute a replacement for the existing scan line, selecting groups of existing scan lines from storage to produce interpolated scan lines in the slow scan direction of the interpolated output image, the step of selecting groups of existing scan lines from storage to produce interpolated scan lines being based on the weight of each existing scan line in the weighted sum of scan lines which are used to compute replacement of the existing scan line, creating an interpolated scan line for each existing scan line in a selected group as a weighted sum of the existing scan line with another scan line, and writing each interpolated scan line created in place of an existing scan line from each of the groups, in which the steps of selecting groups of existing scan lines, creating an interpolated scan line, and writing each interpolated scan line created in place of an existing scan line are repeated in ascending order of weights of existing scan lines in a weighted sum used to compute replacements, starting with groups of scan lines having lowest weights.

Claim 17

A method of processing a digital input image having a plurality of original scan lines of pixel data into an interpolated digital output image comprising the steps of: interpolating the pixel data in each original scan line of the digital input image to provide from each original scan line a plurality of identical scan lines interpolated in a fast scan direction, storing the interpolated scan lines, calculating a value of weight of each existing stored scan line that may be replaced by a scan line interpolated in a slow scan direction, the weight representing a contribution of an existing scan line to be used in the weighted sum with other scan lines to compute a replacement for the existing scan line, selecting groups of existing scan lines from storage to produce interpolated scan lines in the slow scan direction of the interpolated output image, the step of selecting groups of existing scan lines from storage to produce interpolated scan lines being based on the weight of each existing scan line in the weighted sum of scan lines which are used to compute replacement of the existing scan line, creating an interpolated scan line for each existing scan line in a selected group as a weighted sum of the existing scan line with another scan line, and writing each interpolated scan line created in place of an existing scan line from each of the groups, in which the steps of selecting groups of existing scan lines, creating an interpolated scan line, and writing each interpolated scan line created in place of an existing scan line are repeated in ascending order of weights of existing scan lines in a weighted sum used to compute replacements, starting with groups of scan lines having lowest weights.

Claim 19

A method of processing a digital input image having a plurality of original scan lines of pixel data into an interpolated digital output image comprising the steps of: interpolating the pixel data in each original scan line of the digital input image to provide from each original scan line a plurality of identical scan lines interpolated in a fast scan direction, storing the interpolated scan lines, calculating a value of weight of each existing stored scan line that may be replaced by a scan line interpolated in a slow scan direction, the weight representing a contribution of an existing scan line to be used in the weighted sum with other scan lines to compute a replacement for the existing scan line, selecting groups of existing scan lines from storage to produce interpolated scan lines in the slow scan direction of the interpolated output image, creating an interpolated scan line for each existing scan line in a selected group as a weighted sum of the existing scan line with another scan line, and writing each interpolated scan line created in place of an existing scan line from each of the groups, in which the steps of selecting groups of existing scan lines, creating an interpolated scan line, and writing each interpolated scan line created in place of an existing scan line proceed through a gradually decreasing range of scan lines providing the greatest change with respect to original values of pixels in existing scan lines so long as image processing time remains.

Claim 20

A method of processing a digital input image having a plurality of original scan lines of pixel data into an interpolated digital output image comprising the steps of: interpolating the pixel data in each original scan line of the digital input image to provide from each original scan line a plurality of identical scan lines interpolated in a fast scan direction, storing the interpolated scan lines, calculating a value of weight of each existing stored scan line that may be replaced by a scan line interpolated in a slow scan direction, the weight representing a contribution of an existing scan line to be used in the weighted sum with other scan lines to compute a replacement for the existing scan line, selecting groups of existing scan lines from storage to produce interpolated scan lines in the slow scan direction of the interpolated output image, creating an interpolated scan line for each existing scan line in a selected group as a weighted sum of the existing scan line with another scan line, and writing each interpolated scan line created in place of an existing scan line from each of the groups, in which the steps of selecting groups of existing scan lines, creating an interpolated scan line, and writing each interpolated scan line created in place of an existing scan line proceed through a gradually decreasing range of scan lines providing the greatest change with respect to original values of pixels in existing scan lines so long as image processing time remains.