Techniques for improving the resolution of images (either analog images, analytic images, or images having a higher resolution than that of a display device) to be rendered on patterned displays (Fig.10). In one aspect of the present invention, discrete values of a color scan line such as the color scan line (1510) for the color red consist of N samples per emitter (for example, two or more samples (1515r), per emitter Fig. 15)). The samples (1515r) are filtered (e.g. averaged) in order to generate an oversampled color scan line (1520r) (such as a three times oversampled color scan line (Fig. 15)). The new samples of the oversampled color scan line (1520r) are filtered again with box filters (1525) to generate color values (1530) associated with sub-pixel components. The filters (1525) are centered at locations that correspond to the centers of the sub-pixel elements. Thus, the filters (1525) are offset, and consequently operate at distinct positions within the image for each of the color components. Once all of the colors are processed, filter output may be gamma correct (1540) based on the gamma response of a display on which the image is to be rendered.

Methods apparatus and data structures for enhancing the resolution of images to be rendered on patterned display devices

Display apparatus, and methods for displaying images, e.g., text, on gray scale and color monitors (2400) are described. Gray scale displays implemented in accordance with the present invention include displays having a resolution in a first dimension, e.g., the horizontal dimension, which is several times the resolution in a second dimension, e.g., the vertical dimension. Various other displays (2400) of the present invention are capable of operating as both gray scale and color display devices. In one such display, the color filter used to implement a color portion of the display is omitted from another, e.g., gray scale portion of the same display. In such an embodiment, text, e.g., captions, are displayed using the gray scale portion of the display while color images, e.g., graphics, are displayed on the color portion of the display. In another display of the present invention, a color filter (2401) with filter cells (2410, 2411, 2412) that can be switched between a color and a clear mode of operation are employed. When images, e.g., text, are to be displayed as gray scale images, the filter cells (2410, 2411, 2412), corresponding to the portion of the display (2400) to be used to display the gray scale images, are switched to the clear mode of operation. In such an embodiment, the remaining portion or portions of the display (2400) may be used to display color images.

Methods and apparatus for detecting and reducing color artifacts in images

Methods and apparatus are disclosed for sampling image data (1400) and mapping the samples (R, G, B of Cl) to pixel sub-components which form a pixel element (R1-R6) of an LCD display (1402) so that each pixel sub-component has a different portion of the image (1400) mapped thereto and at least one of the pixel sub-components has two or more samples mapped thereto. The methods can be used with conventional color LCD displays that include pixels consisting of three non-overlapping red, green and blue rectangular pixel sub-elements or sub-components. The separately-controllable nature of individual RGB pixel sub-components is used to effectively increase a screen's resolution in one dimension. A scan conversion process maps samples (R, G, B of Cl) of the image data (1400) to individual pixel sub-components, including mapping two or more samples to at least one of the pixel sub-components. As a result, each of the pixel sub-components represents a different portion of the image (1400). The color values are independently generated for each of the red, green, and blue pixel sub-components based on different portions of the image, rather than the color values for the entire pixel being generated based on a single sample or the same portion of the image (1400).

Weighted mapping of image data samples to pixel sub-components on a display device

Methods and apparatus for utilizing pixel sub-components which form a pixel element of an LCD display, e.g., as separate luminous intensity elements, are described. Each pixel of a color LCD display is comprised of three non-overlapping red, green and blue rectangular pixel sub-elements or sub-components. The invention takes advantage of the ability to control individual RGB pixel sub-elements to effectively increase a screen's resolution in the dimension perpendicular to the dimension in which the screen is striped, e.g., the RGB pixel sub-elements are arranged lengthwise. In order to utilize the effective resolution which can be obtained by treating RGB pixel sub-components separately, scaling (910) or super sampling of digital representations of fonts (806) is performed in one dimension at a rate that is greater than the scaling or sampling performed in the other dimension. In some embodiments where weighting is used in determining RGB pixel values, e.g., during scan conversion (914), the super sampling is a function of the weighting. During a scan conversion operation (914), RGB pixel sub-component values are independently determined from different portions of a scaled image. The scan conversion process (914) may involve use of different weights for each color component. Processing (915) to compensate for color distortions, e.g., color fringing, introduced by treating each pixel sub-component as an independent element is described. For horizontally flowing text applications, screens with vertical as opposed to horizontal striping are preferred.

Methods and apparatus for displaying images such as text

Methods and apparatus for displaying images, e.g., text characters, on display devices which have multiple separately controllable luminance elements per pixel are described. Multiple alpha values (1004) are generated per pixel, e.g., one per pixel sub-component. Filtering (1006) is then performed to generate a filtered alpha value (1008) for each pixel sub-component. The filtering operation (1006) uses as its input multiple alpha values, e.g., 5 per pixel. The alpha values (1004) used for the filtering operation (1006) may come from neighbouring pixels (e.g. 932, 934). Accordingly, in the case where character glyphs are combined to form larger images, e.g., texts strings, the filtering operation performed on glyph edge pixels depends on the content of a neighbouring character glyph. In one embodiment unfiltered alpha values (1004) used to represent character glyphs are stored in a glyph cache. After caching, the unfiltered alpha values (1004) from multiple glyphs are combined and then the filtering operation (1006) is performed. To avoid repeated filtering of character glyphs, in another embodiment, character glyphs are padded along their vertical edges, filtered and then stored in the glyph cache. Glyphs are output from the cache as required and then combined with filtered alpha values (1008) corresponding to overlapping image portions being summed. As a result of the summing processes, correct filtered alpha values are generated along glyph edges for the combined image corresponding to multiple glyphs.

G. Murch

Papers

Resolution and addressability: how much is enough?