Systems and methods for temporal subpixel rendering of image data
View Patent ↗Methods are disclosed to render image data over time. In one embodiment, a mapping from image data values to first and second sets of subpixels in a plurality of output frames uses brightness versus viewing angle performance measures to reduce color error when the image is viewed on the display panel at an off-normal viewing angle. In another embodiment, temporal subpixel rendering is used to improve the viewing angle in LCD displays or to improve subpixel rendering in other display technologies.
1. A method for rendering image data on a display panel comprising at least a first set of subpixels of a first color and a second set of subpixels of a second color, the first color having a first brightness versus viewing angle performance measure and the second color having a second brightness versus viewing angle performance measure so as to introduce color error when an image is viewed on the display panel at an off-normal viewing angle, the method comprising:
receiving image data indicating an image and comprising image data values in the first and second colors;
determining a mapping from the image data values in the first and second colors in a single image data plane to the first set of subpixels and the second set of subpixels in a plurality of frames to be displayed on the display panel such that one of the first set of subpixels is substantially equal to an average of two neighboring image data values and one of the second set of subpixels is substantially equal to an average of two neighboring image data values and such that an average of a first image data value and a second image data value adjacent to the first image data value maps to a first subpixel in a first frame and an average of the second image data value and a third image data value adjacent to the second image data value maps to the first subpixel in a second frame; and
outputting to the display a pulse train of on/off patterns for the first set of subpixels and the second set of subpixels over a predetermined number of frames to produce a desired average subpixel luminance.
2. The method of claim 1 wherein determining a mapping further comprises:
determining a first-color viewing angle fall-off value at each of a plurality of off-normal viewing angles using the first brightness versus viewing angle performance measure of the first color;
determining a second-color viewing angle fall-off value at each of a plurality of off-normal viewing angles using the second brightness versus viewing angle performance measure of the second color; and
determining the mapping of the image data values for the first set of subpixels and the second set of subpixels such that the first-color viewing angle fall-off values and the second-color viewing angle fall-off values are proportionally matched between two preselected viewing angles.
3. The method of claim 1 wherein the display panel further comprises a third set of subpixels of a third color.
4. The method of claim 1 wherein the display panel further comprises a fourth set of subpixels of a fourth color.
5. The method of claim 1 wherein the display panel is a liquid crystal display panel.