Subpixel rendering area resample functions for display device

A display system comprising

• a source image receiving unit configured for receiving source image data indicating an input image;
• each color data value in said source image data indicating an input image sample point;
• a display panel substantially comprising a plurality of a subpixel repeating group comprising at least two rows of primary color subpixels;
• each primary color subpixel representing an image reconstruction point for use in computing a luminance value for an output image;
• subpixel rendering circuitry configured for computing a luminance value for each image reconstruction point using said source image data and an area resample function centered on a target image reconstruction point;
• said luminance values computed for each image reconstruction point collectively indicating an output image;
• said subpixel rendering circuitry being further configured for adjusting at least one of said luminance values using a difference-of-cosines (DOC) sharpening filter;
• and
• driver circuitry configured to send signals to said subpixels on said display panel to render said output image.

A method of producing an output image for rendering on a display panel substantially comprising a plurality of a subpixel repeating group comprising at least two rows of primary color subpixels;

• each primary color subpixel representing an image reconstruction point for use in computing a luminance value for the output image;
• the method comprising:
• receiving source image data indicating an input image, each color data value in said source image data indicating an input image sample point;
• performing a subpixel rendering operation using said source image data and an area resample function centered on a target image reconstruction point;
• said subpixel rendering operation producing a luminance value for each target image reconstruction point of said display panel such that said luminance values collectively indicate said output image;
• performing said subpixel rendering operation further comprising producing values v1 and v2 respectively using said area resample function centered on a first target image reconstruction point and said area resample function centered on a second target image reconstruction point at a common input image sample point between said first and second target image reconstruction points, at least one of said values v1 and v2 being a non-zero value;
• and
• sending signals to said subpixels on said display panel to render said output image.

A computer-implemented method of computing coefficients for an N×N image processing filter for use in a subpixel rendering operation to compute a luminance value for a primary color image reconstruction point using primary color input image sample data values, the method comprising:

• receiving a coordinate position of said primary color image reconstruction point relative to an input image grid of input image sample areas, said coordinate position indicating a center of said N×N image processing filter;
• determining, by using a filtering module in a display system, a plurality of input image sample areas located within a boundary of a resample area surrounding said primary color image reconstruction point;
• for each input image sample area located within said boundary,
• for an input image sample area entirely located outside said boundary, assigning a coefficient of zero to a position in the N×N image processing filter corresponding to said input image sample area;
• and
• for an input image sample area at least partially inside said boundary,
• computing a value, v, of an area resample function for said input image sample area, said value v being a function of a volume of said input image sample area inside the boundary of the resample area;
• for an input image sample area at an edge of said boundary assigning a coefficient of v/2 to a position in the N×N image processing filter corresponding to said input image sample area;
• for an input image sample area at a corner of said boundary, assigning a coefficient of v/4 to a position in the N×N image processing filter corresponding to said input image sample area;
• and
• for input image sample areas inside said boundary, assigning value v as said coefficient to a position in the N×N image processing filter corresponding to said input image sample area.