CN1322343A - Mapping image data samples to pixel sub-components on striped display device - Google Patents

Abstract

Methods and apparatus for sampling image data (620) and mapping the samples (622, 623, 624) to pixel sub-components (632, 633, 634) which form a pixel element of an LCD display so that each pixel sub-component (632, 633, 634) has a different portion of the image (620) 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 pixel sub-components (632, 633, 634) can be arranged on the display device to form horizontal or vertical stripes of individual colors. The separately-controllable nature of individual RGB pixel sub-components is used to effectively increase a screen's resolution in the dimension perpendicular to the dimension in which the screen is striped. A scan conversion process maps samples (622, 623, 624) of the image data (620) to individual pixel sub-components, resulting in each of the pixel sub-components representing a different portion of the image. The color values are independently generated for each of the red, green, and blue pixel sub-components based on different portions of the image (620), rather than the color values for the entire pixel being generated based on a single sample or the same portion of the image.

Description

Map image data samples to pixel subcomponents on a striped display device

Background of the invention

1. Related applications

This application is a continuation of U.S. Patent Application Serial No. 09/168,012, filed October 7, 1998, and entitled "Method and Apparatus for Displaying Images, Etc. Method and Apparatus for Dyeing and Rasterizing Operations," a continuation of US Patent Application Serial No. 09/240,654, both of which are incorporated herein by reference.

2. Field of invention

The present invention relates to methods and apparatus for displaying images, and more particularly to display methods and apparatus for displaying images by representing different portions of the image on each of a plurality of pixel subcomponents rather than the entire pixel.

3. Background of the invention

Color display devices have become the display device of choice for most computer users. Displaying colors on a monitor is generally achieved by operating a display device to emit light (such as combining red, green, and blue light into one or more colors that can be perceived by human eyes).

In a cathode ray tube (CRT) display device, different colored lights are generated by using fluorescent coatings which are sequentially applied as dots on the CRT screen. Usually different phosphor coatings are used to produce each of the three colours, red green blue resulting in a repeating sequence of phosphor dots which when excited by an electron beam produce the red green blue colours.

The term pixel generally refers to a dot of light, eg, in a rectangular grid of thousands of dots, which are individually used by a computer to form an image on a display device. For color CRTs, where a single triad of red, green, and blue phosphor dots cannot be addressed, the smallest possible pixel size depends on the focus, alignment, and bandwidth of the electron gun that excites the phosphors. In various known CRT display structures, the light emitted by one or more trichromatic groups of red, green and blue fluorescent dots tends to overlap together, appearing as a monochromatic light source at a certain distance.

In a color display, the intensity of light emitted corresponding to the additive primary colors red, green and blue can be varied to obtain almost any desired color pixel. No color is added, that is, no light is emitted, and black pixels are produced. Adding 100% of all three colors results in white.

FIG. 1 shows a known portable computer 100 comprising a housing 101 , a disk drive 105 , a keyboard 104 and a flat panel display 102 .

Portable personal computers 100 tend to use liquid crystal displays (LCDs) or other flat panel display devices 102 rather than CRT displays. This is because it is easier to achieve smaller size and lighter weight than flat-panel displays. In addition, the power consumption of flat-panel displays is smaller than that of CRT displays of the same size, so it is more suitable for battery-powered applications.

As the quality and cost of flat-panel color monitors continue to improve, they are beginning to replace CRT monitors in desktop applications. Accordingly, flat panel displays, especially LCDs, are becoming more and more popular.

Over the years, most image processing techniques have been developed and optimized for display on CRT display devices, including the generation and display of various fonts, such as character sets, on computer screens.

However, the original text display process does not take into account the unique physical characteristics of flat panel display devices, especially in terms of physical characteristics of RGB color light sources, which are very different from those of CRT devices.

A color LCD display is an exemplary display device that utilizes a plurality of distinct addressable units (referred to herein as pixel subunits or pixel subcomponents) to represent each pixel of a displayed image. Typically, each pixel of a color LCD display is represented by a single pixel element, which typically includes three non-square elements, ie, red, green, and blue (RGB) pixel subcomponents. Thus, a group of RGB pixel subcomponents together form a single pixel element. Known types of LCD displays comprise a series of RGB pixel sub-components, usually arranged in stripes along the display. The RGB stripes generally run the entire length of the display in one direction. The resulting RGB stripes are sometimes referred to as "RGB stripes". Common LCD monitors used in computers are wider than they are tall, and the RGB strips tend to be arranged vertically.

Figure 2A shows a known LCD screen 200 that can be used as a display 102, including a plurality of rows (R1-R12) and columns (C1-C16), each row/column intersecting to form a square representing a pixel element . FIG. 2B shows the upper left corner portion of the known display 200 in detail.

Note how each pixel element (such as (R1, C4) pixel element) in FIG. 2B includes three different subunits or subcomponents, namely red subcomponent 206, green subcomponent 207 and Blue subcomponent 208. Each known pixel sub-component 206, 207, 208 is 1/3 or nearly 1/3 the width of the pixel, and is the same or nearly the same height as the pixel. Thus, when combined, the three 1/3 width pixel subcomponents 206, 207, 208 form a single pixel element.

One known arrangement of RGB pixel subcomponents 206, 207, 208 forms downward vertical color bars along display 200, as shown in FIG. 2A. Thus, in the known manner of FIGS. 2A and 2B, this arrangement of 1/3 width color sub-components 206, 207, 208 is sometimes referred to as a "vertical stripe".

As an example, Figure 2A only shows 12 rows, 16 columns, while common column x row ratios include, for example, 640x480, 800x600 and 1024x768. Note that known display devices generally involve displays arranged in a landscape orientation, ie in FIG. 2A the monitor width is wider than its height and the bars are arranged in a vertical orientation.

LCDs are manufactured with pixel subcomponents arranged in several additional patterns, such as in a camcorder viewfinder, typically including Z and delta shapes. Although the features of the present invention are applicable to this type of pixel sub-component arrangement, since RGB stripe structures are more common, exemplary embodiments of the invention are described in terms of RGB stripe displays.

By convention, each group of pixel subcomponents of a pixel element is treated as a single pixel unit, so that in known systems the light intensity values of all pixel subcomponents of a pixel element are generated from the same part of the image. For example, consider the image represented by grid 220 shown in FIG. 2C. In FIG. 2C, each square represents an area of the image, and the image area is to be represented by a single pixel element, such as the red, green, and blue pixel subcomponents corresponding to square 230. In FIG. 2C, the individual image samples from which the light intensity values are generated are represented by the dashed circles. Note how known systems use a single sample 222 of the image 220 to generate light intensity values for each of the red, green and blue pixel subcomponents 232,233,234. Thus, in known systems, the RGB pixel subcomponents are usually used as a group to generate a single color pixel corresponding to a single sample of the image to be represented.

The light emitted by each group of pixel subcomponents is effectively added together to produce a monochromatic effect whose hue, saturation and intensity depend on the values of the individual three pixel subcomponents. For example, the potential intensity of each pixel subcomponent is 0-255. If the intensity of all three pixel subcomponents is specified to be 255, the pixel seen by the naked eye is white. However, if all three pixel subcomponents give values that cut off each three-pixel component, the pixel is seen as a black pixel. Varying the individual intensity of each pixel subcomponent produces millions of colors between these two extremes.

In known systems, since a single sample is mapped to three pixel subcomponents (each subcomponent is 1/3 the width of a pixel), left and right pixel subcomponents occur due to the fact that the centers of these cells are offset by 1/3 of the center of the sample. Spatial displacement of components.

Consider, for example, an image to be represented, which is a red cube with zero green-blue components. When displayed on an LCD display of the type shown in Figure 2A, the apparent position of the cube on the display will be offset by 1/3 of a pixel to its actual position as a result of the displacement between the sample and the green image subcomponent on the left side. Likewise, the blue cube will be shifted 1/3 of a pixel to the right. Thus, known imaging techniques applied to LCD panels can result in undesired image displacement errors.

Text characters represent a class of images that are particularly difficult to display accurately, given the typical resolution of flat panel displays of 72 or 96 dots (pixels) per inch (dpi). Such a display resolution is far worse than the 600dpi supported by most printers, and even higher resolutions can be found in most commercial printed texts such as books and periodicals.

Due to the low display resolution of most video display devices. Thus there are not enough pixels to draw a smooth character shape, especially in normal text in sizes of 10, 12 and 14 points. At this general text size, the grading between different sizes and weights of the same typeface, such as thickness, is much coarser than its printed counterpart.

The relatively coarse size of standard pixels is confusing, and the type characters displayed have uneven edges. For example, the coarse size of the pixels tends to square the serifs, dashes, or end (such as bottom) decorations of the strokes that form font characters, making it difficult to accurately display many highly readable or decorative fonts that exclusively use serifs .

This type of problem is particularly noticeable in stems (eg, the elongated vertical portions of characters). Since a pixel is the smallest display unit of an ordinary monitor, it is impossible to display character stems with conventional techniques of less than one pixel stem thickness. Furthermore, the stem thickness can only be increased by one pixel at a time, so that the stem thickness jumps from one pixel to two pixels wide. Typically, a character stem that is one pixel wide is too light, and a character stem that is two pixels wide is too bold. Since forming a bold font for small characters on a display screen involves changing the thickness of the stem from one pixel to two pixels, the weight difference between the two is 100%. In print, a bold font may generally only be 20 or 30 percent heavier than its regular or roman equivalent. Typically, this "one pixel, two pixel" problem has been treated as an inherent characteristic that display devices must accept.

Previous research work in the field of character display has focused in part on developing anti-aliasing techniques that can improve character display on CRT displays. A common anti-aliasing technique involves applying a gray scale to pixels including the edges of characters. In fact, this blob shape reduces the spatial frequency of the edges, but better approximates the original character shape. Although known anti-aliasing techniques can significantly improve the quality of characters displayed on CRT display devices, many of these techniques are ineffective when applied to LCD display devices that differ significantly from CRT displays in the arrangement of pixel subcomponents up.

While anti-aliasing techniques help to resolve the aliasing problems associated with displaying lower resolution text representations at least on CRT displays, prior to this invention the issues of pixel size and inability to accurately display character stem widths were considered necessary A fixed property of allowed display devices.

For this reason, there is clearly a need for new and improved methods and apparatus for displaying text on flat panel display devices. It is desired that at least some of the new methods be applicable to existing display devices and computers, and at least some of the methods and apparatuses are also desired to improve the quality of text displayed on new types of computers utilizing, for example, new display devices and/or new text display methods.

In many computer applications, although text display (a special case of graphics) is of greatest concern, improved methods and equipment are also required to accurately and clearly display other graphics, geometric shapes (such as circles, squares, etc.) elephant.

Summary of the invention

This invention relates to methods and apparatus for displaying images by representing different portions of the image on multiple pixel sub-components rather than on entire pixels.

The inventors of the present invention recognized the well-known principle that the human eye is much more sensitive to the luma edge (where light intensity changes) than to the chroma edge (where color intensity changes). That's why it's hard to read red text on a green background. The inventors have also recognized the well known principle that the eye has unequal sensitivity to red, green and blue. In fact, of the 100% light intensity of an all-white pixel, the red pixel subcomponent contributes about 30% to the overall perceived luminance, green 60%, and blue 10%.

Various features of the invention refer to the use of individual pixel subcomponents of the display as independent sources of light intensity, thereby increasing the effective resolution of the display by up to a factor of three in the dimension perpendicular to the direction of the RGB stripes. This can achieve a noticeable improvement in visible resolution.

Although the method of the present invention may result in some degradation of chrominance quality compared to known display techniques, as discussed above, the human eye is more sensitive to luma edges than to chrominance edges. Thus, the present invention is able to provide a significant improvement in image quality compared to known dyeing techniques, even when taking into account the negative impact of the inventive technique on color quality.

As discussed above, known monitors tend to use vertical stripes. Since character stems appear vertically, the ability to accurately control the thickness of vertical lines tends to be more important than the ability to control the thickness of horizontal lines when coloring horizontally flowing text.

With these in mind, it was concluded that, at least for text applications, it is highly desirable for a monitor to have maximum resolution in the horizontal rather than vertical direction. Thus, various display devices implemented in accordance with the present invention utilize vertical rather than horizontal RGB striping. It provides monitors that, when used in accordance with the present invention, have greater resolution in the horizontal direction than in the vertical direction. However, the invention is equally applicable to monitors with horizontal RGB strips, resulting in increased resolution in the vertical direction compared to conventional image coloring techniques.

In addition to new display devices suitable for use when processing pixel subcomponents as independent sources of light intensity, the present invention relates to new and improved text, graphics, and image coloring techniques that facilitate the use of pixel subcomponents in accordance with the present invention .

The display of images, including text, involves steps including scan conversion. Scan conversion is the process of converting the geometric representation of an image into a bitmap. The scan conversion operation of the present invention involves mapping different parts of an image to different pixel subcomponents. This differs significantly from known scan conversion techniques where the same portion of the image is used to determine the light intensity values used for each of the 3 pixel subcomponents representing a pixel.

The scan conversion operations of the present invention can be used with other operations including image scaling, rendering and color processing, taking into account the individually controllable nature of pixel subdivision boundaries within images and pixel subcomponents of flat panel display devices.

Numerous additional features, embodiments and advantages of the methods and apparatus of the present invention are set forth in the detailed description below.

Brief description of the drawings

Figure 1 shows a known portable computer.

Figure 2A shows a known LCD panel.

Fig. 2B shows a part of the known display screen of Fig. 2A in more detail than Fig. 2A.

Figure 2C illustrates the image sampling operation performed in a known system.

The known steps shown in Figure 3 involve the preparation and storage of character information for later use in text generation and display.

Figure 4 illustrates an electronic book with flat panel displays arranged in a vertical arrangement according to an embodiment of the present invention.

Figure 5 shows a computer system implemented in accordance with the present invention.

Figure 6 illustrates image sampling performed in accordance with an exemplary embodiment of the present invention.

Figure 7A shows a color flat panel display in accordance with the present invention.

FIG. 7B shows a portion of the display screen of FIG. 7A.

Figure 7C shows a display screen implemented in accordance with another embodiment of the present invention.

Figure 8 shows various elements (eg, routines) included in the memory of the computer system of Figure 5 for providing text images on the display of the computer system.

FIG. 9 illustrates a method for providing displayed text according to an embodiment of the present invention.

10A and 10B illustrate scaling operations performed in accordance with various exemplary embodiments of the present invention.

11A and 11B illustrate hinting operations performed in accordance with various exemplary embodiments of the present invention.

12A and 12B illustrate scan conversion operations performed in accordance with various exemplary embodiments of the present invention.

Fig. 13 shows in detail the scan conversion process applied to the first column of the image data shown in Fig. 12A.

Figure 14 illustrates a weighted scan conversion operation performed in accordance with one embodiment of the present invention.

Figure 15 shows a high resolution representation of a character to be displayed on a field of pixels.

Figure 16 shows how the characters of Figure 15 can be represented using known techniques.

17-20 illustrate different ways in which the characters shown in FIG. 15 can be represented by various text coloring techniques according to the present invention.

A detailed description

As noted above, the present invention is directed to displaying images (such as text and/or graphics) on a display device by representing different portions of the image on each of a plurality of pixel subcomponents rather than on an entire pixel. Methods and equipment.

Instead of treating a group of RGB pixel subcomponents comprising a pixel as a single light intensity unit, the various methods of the present invention use each pixel subcomponent as a separate and independent light intensity source. This allows a display device with RGB horizontal or vertical bars to be processed with an effective resolution on a scale perpendicular to the bar direction that is 3 times greater than on the bar scale. The various devices of the present invention are directed to display devices and control devices that take advantage of the ability to individually control pixel subcomponents.

A. Example Computing and Hardware Environment

Figure 5 and the following discussion provide an overview of an exemplary device capable of implementing at least some features of the present invention. Various methods of the present invention are generally described by computer-executable instructions (such as program modules), and such instructions are executed by computer devices such as personal computers. Other features of the invention will be described in terms of physical hardware such as display device elements and screens.

In addition to the specifically described computer means, other devices may be used to implement the method of the invention. Program modules may include routines, programs, objects, components, data structures, etc. that perform a certain task or implement particular abstract data types. Additionally, those skilled in the art will appreciate that at least some aspects of the present invention may be implemented in other configurations, including handheld devices, multiprocessor systems, microcomputer-based or programmable Consumer electronics, network computers, minicomputers, set-top boxes, mainframe computers, monitors, etc. At least some aspects of the invention may also be practiced in distributed computing environments where tasks are performed by remote processing devices that are linked through a communications network. In some distributed computing environments, program modules may be located in local and/or remote memory devices.

Referring to Figure 5, an exemplary apparatus 500 for implementing at least some aspects of the present invention comprises a general purpose computing device. Personal computer 520 may include a processing unit 521 , a system memory 522 , and a system bus 523 coupling various system elements including system memory 522 to processing unit 521 . System bus 523 is any of several types of bus structures, including a memory bus or memory controller, a peripheral bus, and a local bus employing any of the bus structures. System memory 522 may include ROM 524 and/or RAM 525. A basic input/output system 526 (BIOS) may be stored in ROM 524 and includes basic routines that help pass information between units within personal computer 520, such as during start-up. The personal computer 520 may also include a hard disk drive 527 (not shown) for reading and writing to a hard disk, a magnetic disk drive 528 for reading and writing to a (e.g., removable) magnetic disk 529, and a removable (magneto-optical) optical disk 531 (e.g., a CD or Other (magneto-optical) optical media) optical disc drive 530 for reading and writing. Hard disk drive 527, magnetic disk drive 528, and optical (magneto-optical) drive 530 may be coupled to system bus 523 by hard disk drive interface 532, magnetic disk drive interface 533, and optical (magneto-optical) drive interface 534, respectively. These drives and their associated storage media provide non-volatile storage of machine-readable instructions, data structures, program modules and other personal computer 520 data. Although the exemplary environment described here employs a hard disk, a removable magnetic disk 529, and a removable optical disk 531, those skilled in the art will appreciate that other types of storage media can be used instead of or in addition to the above-mentioned storage devices, such as cartridges. tape, flash memory card, digital video disk, Bernoulli cartridge, RAM, ROM, etc.

For example, several program modules such as operating system 535, one or more application programs 536, other program modules 537 and/or program data 538 may be stored on hard disk 523, magnetic disk 529, (magneto-optical) optical disk 531, ROM 524 or RAM 525. The user can send commands and information into the personal computer 520 through the input devices of the keyboard 540 and the pointing device 542 . Other input devices (not shown) such as a microphone, joystick, game console disc, satellite dish, scanner, etc. may also be included. These and other input devices are typically connected to processing unit 521 through serial port interface 546 coupled to system bus 523 . However, other interfaces such as a parallel port, a game console port, or a universal serial bus (USB) may be used to connect the input device. A monitor 547 or other type of display device may also be connected to the system bus 523 via an interface such as a video adapter 548 . In addition to the monitor 547, the personal computer 520 may include other peripheral output devices (not shown) such as speakers and a printer.

Personal computer 520 may operate in a network environment that defines logical connectivity to one or more remote computers, such as remote computer 549 . Remote computer 549 may be another personal computer, server, router, network PC, peer-to-peer device, or other public network node, and may include many or all of the elements described above with respect to personal computer 520 . The logical connections shown in FIG. 5 include a local area network (LAN) 551 and a wide area network (WAN) 552, the Internet and an intranet.

When applied to a LAN, the personal computer 520 can be connected to the LAN 551 through a network interface adapter (or "NIC") 553 . When applied to a WAN (eg, the Internet), the personal computer 520 may include a modem or other means of establishing communications over the wide area network 552 . Modem 554 (internal or external) can be connected to system bus 523 via serial port interface 546 . In a networked environment, at least some program modules of the personal computers 520 may be stored on the remote memory device. A network connection is one example and other means of establishing a communications link between the computers can be used.

FIG. 7A shows a display device 600 according to one embodiment of the present invention, which is suitable for use in, for example, a portable computer or other system where a flat-panel display is desired. The display device 600 may be configured as an LCD display. In one embodiment, the display and control logic of the known computer 100 are replaced by the display device 600 and display control logic (e.g., routines) of the present invention to provide the portable computer with horizontal RGB strips and graphics for representing different parts of the image. Pixel subcomponent.

As shown, for a display of 16*12 pixels, the display device 600 includes 16 columns of pixel elements C1-C16 and 12 rows of pixel elements R1-R12. Like most computer monitors, display 600 is configured to be wider than it is tall. For ease of illustration, although the display 600 is limited to 16 x 12 pixels, it should be understood that a monitor of the type shown in FIG. 640×480, 800×600, 1024×768, and 1280×1024, and ratios that result in square displays.

Each pixel element of the display 600 includes three sub-components, namely a red pixel sub-component 602 , a green pixel sub-component 604 and a blue pixel sub-component 606 . In the embodiment of FIG. 7A, the height of each pixel sub-component 602, 604, 606 is equal to or nearly equal to 1/3 of the height of the pixel, and the width is equal to or nearly equal to the width of the pixel.

In monitor 600, the RGB pixel sub-components are organized into horizontal stripes, as opposed to the vertical stripe structure employed in monitor 200 described above. The monitor 600 can be used in certain graphics situations, where a larger vertical resolution than horizontal is required according to the application requirements.

FIG. 7B shows the upper left corner of the display 600 in detail, the horizontal RGB strip pattern is clearly visible, and the letters R, G, B denote the corresponding color pixel sub-components.

FIG. 7C shows another display device 700 constructed in accordance with the present invention. Figure 7C shows a vertical RGB strip as applied in a display device such as an LCD display, having more vertical pixel elements than horizontal pixel elements. Although illustrated as a 12x16 display, it should be understood that display 700 may be constructed with any number of pixel columns/rows, including column/row ratios that result in a square display.

The display device 700 is fully applicable to occasions requiring vertical display of horizontally flowing text. Like the monitor of FIG. 2A, each pixel element includes 3 pixel sub-components, ie R, G, B pixel sub-components.

Although display 7A is suitable for certain graphic applications, accurate representation of character stems (the elongated, vertical portions of characters) is far more important than serif representation in producing high quality characters. The vertical bars have different advantages and when used in accordance with the present invention allow the width of the stems to be adjusted by 1/3 of a pixel at a time. Thus, using a display device such as the device 200 or 700 with a vertical bar structure together with the display method of the present invention can provide higher quality text than the known horizontal bar structure (where stem width adjustment is limited to 1 pixel increments) .

Another advantage of vertical bars is the ability to adjust character spacing in width in increments smaller than a pixel size (eg, 1/3 pixel size increments). Character spacing is an important text characteristic for legibility, so applying vertical bars results in improved text spacing and finer stem weights.

Figure 8 shows various units, such as routines, included in the memory of the computer system of Figure 5 for providing text images on the display of the computer system of the present invention.

As shown, the application routine 536 (which may be, for example, a word processor application) includes a text output subcomponent 801 . The text output sub-component 801 is responsible for outputting the text information indicated by the arrow 813 to the operating system 535 for presentation on the display device 547 . The text information includes, for example, information identifying a character to be colored, a font to be used during description, and a dot size of the character to be colored.

Operating system 535 includes various elements that control the display of text on display device 547 , including display information 815 , display adapter 814 , and graphics display interface 802 . Display information 815 includes, for example, scaling information and/or foreground/background color information to be applied during staining. The display adapter receives bit-mapped images from graphics display interface 802 and generates a video signal that is supplied to video adapter 548 for optical display by display 547 . Arrow 816 represents the passing of the bitmap image from graphics display interface 802 to display adapter 814 .

Graphics display interface 802 includes routines for handling graphics and text. Unit 804 is a type rasterizer for processing text. Type rasterizers are responsible for processing textual information obtained from applications 536 and generating bitmap representations therefrom. Type rasterizer 804 includes character data 806 and coloring and rasterization routines 807 .

Character data 806 may include, for example, vector graphics, lines, points, and curves, providing a high-resolution digital representation of one or more groups of characters.

As shown in FIG. 3, it is known to process text characters 302 to produce high resolution digital representations thereof, as data 806, which can be stored in memory for use in text generation. Therefore, the generation 304 and storage 306 of data 806 will not be discussed here.

The tinting and rasterization routine 807 includes a scan conversion subroutine 812 and may also include a scaling subroutine 808 , a hinting subroutine 810 , and a color compensation subroutine 813 . While it is commonplace to perform scan conversion operations to render text images, the routines and subroutines of the present invention differ from known programs in which the RGB pixel subcomponents of the screen are considered, utilized, or treated as capable of being used for Represents separate light intensity entities to tint different parts of the image.

B. Scan conversion operation

Scan conversion involves converting a scaled geometric shape representing a character into a bit-mapped image. Conventional scan conversion operations treat pixels as independent units into which corresponding portions of the scaled image can be mapped. Thus in a conventional scan conversion operation, the same portion of the image is used to determine the light intensity value to be used for each RGB pixel subcomponent of the pixel element into which a portion of the scaled image is mapped. Figure 2C is an example of a known scan conversion process which involves sampling an image to be represented as a bitmap and generating light intensity values from the sampled values.

According to the present invention, the RGB pixel sub-components of a pixel are treated as independent light intensity units. Thus, each pixel subcomponent is treated as a separate light intensity component into which a separate portion of the scaled image can be mapped. Thus, the present invention maps different portions of a scaled image into different pixel subcomponents, providing higher resolution than known scan conversion techniques. That is, in various embodiments, different portions of the scaled image may be used to independently determine the light intensity value to use for each pixel subcomponent.

Figure 6 illustrates an exemplary scan conversion implemented in accordance with one embodiment of the present invention. In the illustrated embodiment, image samples 622, 623, 624 are spatially displaced from the image represented by grid 620 to generate red, green, and blue light intensity values corresponding to portions 632, 633 of generated bitmap image 630 , 634 related. Sampling the image data and mapping each of the image samples 622, 623, and 624 to the red, green, and blue pixel subcomponents associated with portions 632, 633, and 634 (as shown in FIG. 6 ) represents the corresponding mapping of these samples to Examples of the actions of the steps of the individual pixel subcomponents. In the example of Figure 6, the red and blue image samples are moved by -1/3 and +1/3 of the pixel width respectively in distance from the green samples, thereby avoiding the known sampling/image representation shown in Figure 2C The displacement problem encountered by the law.

In the example shown in the figure, pixel subcomponents that are "on" in the bitmap image produced by the scan conversion operation are indicated by white. Pixel subcomponents that are not white are "cut off".

In black text, "on" means that the light intensity value associated with that pixel subcomponent is controlled so that no light is output from that pixel subcomponent. Assuming a white background pixel, no "on" subcomponents are assigned light intensity values that cause them to output their full light output.

When using foreground and background colors, "communication" means specifying a certain value for a certain pixel sub-component. If all three pixel sub-components are used to generate the foreground color, this value will produce the specified foreground color. If all three pixel subcomponents are used to generate the background color, specify the values that produce the specified background color for the non-"pass" pixel subcomponents.

The first technique to determine whether a pixel subcomponent is "on" when scaling is to determine whether the center of the scaled image segment (represented by a portion of the scaling grid) that is mapped to the pixel subcomponent is at The scaled representation of the image to be displayed is within. As in FIG. 12A, when the center of grid block 1202 is inside image 1004 (shown in FIG. 11A), pixel subcomponents C1, R5 are turned on. Another technique is to determine whether 50% or more of the scaled image block mapped to the pixel subcomponent is occupied by the image to be displayed. If occupied, the pixel subcomponent is turned on. For example, when the scaled image block represented by grid block 1202 is at least 50% occupied by image 1004, the corresponding pixel sub-component C1, R5 is turned on. In the examples of Figures 12A, 12B, 13 and 14 discussed below, a first technique for determining when a pixel subcomponent is turned on is employed.

Figure 12A shows the scan conversion operation performed on a scaled cue image 1014 displayed on a horizontal bar display device. Examples of zooming and hinting operations that can result in image 1014 are described in more detail below with reference to FIGS. 10A and 11A . To briefly summarize these exemplary zooming and hinting operations, however, FIG. 10A shows a zooming operation on a high resolution representation of the letter i 1002, which is the intended display of the letter on a horizontal bar monitor such as that shown in FIG. 7A . Note that in this example a ratio of x1 is applied in the horizontal (X) direction and a ratio of x3 is applied in the vertical (Y) direction. This results in a scaled character 1004 that is three times taller and the same width as the original character 1002 . Scaling by other amounts is also possible.

When used with the scan conversion operations of the present invention, hinting may involve scaling the alignment of characters (such as characters 1004 of FIG. 11A ) in grid 1102 as part of a subsequent scan conversion operation. It can also involve warping the outline of the image, allowing the image to better conform to the shape of the grid. The grid is defined as the physical size of the pixel elements of the display device. The hinting operation of FIG. 11A results in hinting image 1014 .

The scan conversion operation of FIG. 12A results in a bitmap image 1204 . Note how each pixel subcomponent of the columns C1-C4 of the bitmap image is determined from a different block of the corresponding column of the scaled hint image 1014. Note also how the bitmap image 1204 includes a base 2/3 pixel height and a point 2/3 pixel height aligned along the green/blue pixel boundary. Known text imaging techniques result in very inaccurate images, ie the base is full pixel height and the dot size is full pixel size.

Figure 12B shows the scan conversion operation performed on the cue image 1018 displayed on the vertical bar display device. Examples of zooming and hinting operations that can result in image 1018 are described in more detail below with reference to FIGS. 10B and 11B . To briefly summarize these exemplary zooming and hinting operations, however, FIG. 10B shows a zooming operation on a high-resolution representation of the letter i 1002, which is how the letter would look on a vertical bar monitor such as that shown in FIGS. 2A and 7C. Shown as expected. Note that in this example a ratio of x3 is applied in the horizontal (X) direction and a ratio of x1 is applied in the vertical (Y) direction. This results in a scaled character 1008 that is the same height as the original character 1002 and three times wider. Scaling by other amounts is also possible.

Figure 1 IB shows a hinting operation that results in scaling the alignment of characters 1008 in grid 1102, which is used as part of the following scan conversion operation. It can also involve warping the outline of the image, allowing the image to better conform to the shape of the grid. The hinting operation of FIG. 11B results in hinting image 1018 .

The scan conversion operation of FIG. 12B results in a bitmap image 1203 . Note how each pixel subcomponent of the bitmap image rows R1-R8 is determined from a different block of the corresponding row of the scaled hint image 1018. Note also how the bitmap image 1203 includes a 2/3 pixel width stem aligned along the red/green pixel border on the left edge, and also note the use of a dot 2/3 pixel width, known Text imaging techniques can result in very inaccurate images, with stems at full pixel width and dots at full pixel size.

Figure 13 shows in more detail the scan conversion process performed on the first column of the image 1014 shown in Figure 12A. In graphic scan conversion processing, a block of image 1014 is used to control the light intensity value associated with each pixel subcomponent, which results in each pixel subcomponent being controlled by an equally sized portion of image 1014.

Can be used for weighting in scan conversion operations. When weighting, different sized regions of the image can be scaled to determine whether a particular pixel subcomponent is on or off, or somewhere in between (eg, grayscale scaling).

As mentioned above, the human eye perceives light intensities from different colored light sources in different ratios. For the perceived brightness of white pixels, the contribution rate is: about 60% for green, about 30% for red, and about 10% for blue; the brightness of white pixels is the maximum light intensity output of the red, green and blue pixel subcomponents caused by.

According to one embodiment of the invention, weighting is applied during scan conversion such that the 60% scaled image area mapped to a pixel is used to determine the intensity of a green pixel subcomponent, and the respective 30% mapped to the same pixel is used to determine the intensity of the green pixel subcomponent. The % scaled image area determines the intensity of the red pixel subcomponent, and a separate 10% scaled image area mapped to the same pixel determines the intensity of the blue pixel subcomponent.

In a particular embodiment of the invention, during scaling operations, the image is scaled by a factor of 10 in the direction perpendicular to the stripes than in the direction of the stripes, which facilitates weighted scan conversion operations. After prompting, the scaled image is processed during scan conversion using a weighted scan conversion operation of the type described above.

Figure 10A shows an image 1002 that has been scaled by a factor of 3 in the vertical direction and by a factor of 1 in the horizontal direction. In contrast, FIG. 14 shows the weighted scan conversion operation performed on the first column 1400 of the scaled hint version of an image 1002 that has been scaled by a factor of 10 in the vertical direction and by a factor of 1 in the horizontal direction. In Fig. 14, the portion of the hint image corresponding to a single pixel consists of 10 blocks. In accordance with the weighted scaling technique described above, the first three blocks of each pixel region of the scaled image are used to determine the intensity value of the red pixel subcomponent corresponding to a pixel in the bitmap image 1402. The next set of six blocks for each pixel region of scaled image 1400 is used to determine the intensity value of the green pixel subcomponent corresponding to the same pixel in bitmap image 1402, leaving scaled image 1400 for each The last block of the pixel area, used to determine the light intensity value of the blue pixel sub-component.

As shown in FIG. 14, this process results in the blue pixel subcomponent of column 1, row 4 and the red pixel subcomponent of column 1, row 5 of the bitmap image 1402 being switched on, while the remaining pixel subcomponents of column 1 are switched on. The component is cut off.

In general, the scan conversion process of the present invention has been described in terms of pixel subcomponents being "on" or "off".

Embodiments of the present invention, especially for use with graphic images, involve the use of gray scale techniques. In such embodiments, as in the embodiments described above, the scan conversion operation involves independently mapping portions of the scaled hint image to corresponding pixel sub-components to form a bit-mapped image. In gray scale embodiments, however, the intensity value assigned to a pixel subcomponent is determined as a function of the portion of the zoomed image area mapped to that pixel subcomponent (occupied by the zoomed image to be displayed) of. For example, if a certain pixel subcomponent can be assigned an intensity value between 0 and 255, with 0 being effectively cut off and 255 being full intensity, then the image to be displayed occupies 50% of the scaled image block (lattice block) would result in pixel subcomponents being assigned 127 intensity values as a result of mapping the scaled image block to the corresponding pixel subcomponent. According to the present invention, adjacent pixel subcomponents of the same pixel have their intensity values determined independently as a function of another part of the scaled image, such as a block.

C. Sample staining routine

The scan conversion operation of the present invention may use the tinting and rasterization routine 807 of FIG. 9 to allow text to be displayed in accordance with one embodiment of the present invention. As shown, routine 807 begins at step 902, where the routine is executed under the control of the operating system, eg, based on text messages received from application 536. In step 904 , input is received by text coloring and rasterization routine 807 . The input includes text, font, and point size information 905 obtained from the application program 536 . Additionally, the input includes scaling information and/or foreground/background color information and pixel size information 815 obtained, for example, by the operating system from monitor settings stored in memory. The input also includes data 806, which includes a high-resolution representation (eg, in the form of lines, dots, and/or curves) of the text characters to be displayed.

With the input received in step 904, operation proceeds to step 910 where scaling subroutine 808 may be used to perform a scaling operation. Non-square scaling can be performed as a function of the orientation and/or number of pixel subcomponents contained in each texel. Specifically, high resolution character data 806 (eg, line and dot representations of characters to be displayed as specified by received text and font information) is scaled in a direction perpendicular to the bar at a greater rate than the bar direction. This enables subsequent image processing operations to take advantage of the higher resolution, which according to the invention is achieved by using individual pixel subcomponents as independent light intensity sources.

Details of exemplary scaling operations that can be used with the scan conversion operations of the present invention are disclosed in U.S. Patent Application Serial No. 09/168,012 entitled "Method and Apparatus for Displaying Images, such as Text," e.g., FIGS. 10A, 10B and corresponding text description. This application is a continuation of US Patent Application Serial No. 09/168,012, which was previously incorporated herein by reference.

Referring again to FIG. 9, operation proceeds to step 912, where hinting of the zoomed image may be performed by execution of the hinting subroutine 810. The term grid fit is sometimes used to describe the cueing process.

Hinting involves scaling the alignment of characters (eg, characters 1004, 1008) in grids 1102, 1104, which are used as part of subsequent scan conversion operations. It also involves warping the contours of the image, allowing the image to better conform to the shape of the grid. The grid is determined as a function of the physical size of the pixel elements of the display device. Details of exemplary hinting operations that can be used with the scan conversion operations of the present invention are disclosed in US Patent Application Serial No. 09/168,012, eg, FIGS. 11A, 11B and accompanying text. Operation then proceeds to step 914 where a scan conversion operation is performed in accordance with the present invention, for example, by executing the scan conversion subroutine 812, as disclosed herein.

Once a bitmapped representation of the text to be displayed has been generated in step 914 of FIG. 9, it may be output to a display adapter or further processed for color processing operations and/or color adjustments to enhance image quality. Details of exemplary color processing operations and color adjustments that can be used with the scan conversion operations of the present invention are disclosed in US Patent Application Serial No. 09/168,012.

The processed bitmap 918 is output to the display adapter 814, and the operation of the routine 807 is suspended upon receipt of additional data/images to be processed.

Figure 15 shows a high resolution representation of the letter n to be colored superimposed on a grid representing a 12x12 pixel array with horizontal bars.

Figure 16 shows how conventional display techniques can be used to color the letter n of Figure 15, showing full size pixels each comprising three pixel subcomponents. Note how the full pixel size limitation causes a shape mutation at the letter ridge, resulting in aliasing and a flatter top.

Figure 17 shows how the coloring of the letter n can be improved according to the invention with a 2/3 pixel height base. The substrate is formed in row 10, columns 1-4 and 8-10 with 2 pixel subcomponents instead of all three pixel subcomponents. Also notice how the ridges of the letters have been improved. The improved method is that the width of the ridges is the entire pixel height, but each horizontal full-height pixel is arranged vertically in a staggered 1/3 pixel height, forming a ratio of 1/3 pixel height as shown in Figure 16. Shows more accurate and smoother ridges.

Figure 18 shows how the ridge of the letter n can be reduced in thickness from one pixel thickness to 2/3 pixel thickness according to the present invention.

Figure 19 shows how the base of the letter n is reduced to a minimum thickness of 1/3 of a pixel and also how the ridge of the letter n is reduced to 1/3 of a pixel thickness in accordance with the present invention.

Fig. 20 shows how the letter n is represented according to the invention, with the base and ridge having a thickness of 1/3 of a pixel.

An example of a display device on which the scan conversion operation of the present invention can be implemented is shown in FIG. 4, which shows a computerized electronic book device 400. As shown in FIG. First and second display screens 402,404. A display device of the type shown in FIG. 7C is used, for example, as the displays 402 , 404 of the electronic book 400 of FIG. 4 . The electronic book 400 further includes an input device such as a keypad or keyboard 408 and a data storage device such as a CD drive 407 . The provided hinge 406 can fold the electronic book 400 and protect the displays 402 and 404 when not in use. The electronic book 400 may be powered by an internal battery. Likewise, other portable computer embodiments of the present invention may also be battery powered.

While the present invention has been described for the most part to render text, it should be understood that the present invention is equally applicable to graphics to reduce aliasing and increase the effective resolution achievable with bar displays such as conventional color LCD displays. In addition, it should be understood that many of the techniques of the present invention can be used to process bit-mapped images (eg, scanned images) for display.

In light of the invention described herein, those skilled in the art will appreciate various additional embodiments and modifications to the embodiments discussed herein. It should be understood that such embodiments do not depart from the invention and are within the scope of the invention.

Claims (38)

1. A method of improving the resolution of a displayed image in a computer system comprising a processing unit and a display device for displaying the image, said display device having a plurality of pixels each comprising at least three pixels Element sub-components, each pixel sub-component has different colors, it is characterized in that the method comprises the following steps: Maps a sample of information representing an image to individual pixel subcomponents of a pixel, rather than mapping the sample to the entire pixel, to which each pixel subcomponent has mapped a set of spatially distinct one or more samples, pixel sub-components of a plurality of pixels are arranged to form a strip of pixel sub-components of the same color on the display device; generating separate luminous intensity values for each pixel subcomponent of the pixel based on the different sets of one or more samples mapped thereto; and The image is displayed on the display device using separate luminous intensity values, resulting in each pixel sub-component of the pixel representing a different portion of the image rather than the entire pixel. 2. The method of claim 1, further comprising the step of: before the step of mapping the samples, making the information representing the image larger in a direction perpendicular to the strip than in a direction parallel to the strip Large factor scaling. 3. The method of claim 1, wherein the step of mapping samples is performed such that each pixel subcomponent of a pixel has one and only one of the samples mapped thereto. 4. The method of claim 1, wherein the step of mapping samples is performed such that at least one of the pixel subcomponents of the pixel has two or more of the samples mapped thereto. 5. The method of claim 1, wherein a different number of samples is mapped to each pixel subcomponent of a pixel. 6. The method of claim 1, wherein the information representing the image includes an outline of the image, with a foreground color and a background color associated therewith. 7. The method of claim 1, wherein the step of generating a light intensity value for each pixel subcomponent includes a value based on the relative position of the image and one or more samples mapped to the pixel subcomponent. Group selection steps to turn the light intensity value on or off. 8. A method of improving the resolution of a displayed image in a computer system comprising a processing unit and a display device for displaying the image, said display device having a plurality of pixels each comprising at least three pixels Pixel sub-components, each pixel sub-component has a different color, the at least three pixel sub-components include a first pixel sub-component, a second pixel sub-component and a third pixel sub-component, characterized in that The method includes the following actions: Acquiring information representing an image, thereby obtaining multiple samples; mapping a first set of one or more samples to a first pixel sub-component of a pixel of a display device, the pixel sub-components of a plurality of pixels of the display device being arranged to form pixel sub-components of the same color on the display device Bands; mapping a second set of one or more samples to a second pixel subcomponent of the pixel; mapping a third set of one or more samples to a third pixel subcomponent of a pixel, wherein the first, second, and third sets are spatially distinct from each other; For each of the first, second, and third pixel subcomponents, generating a respective luminous intensity value based on the particular set of one or more samples mapped thereto; and An image is displayed on a display device by controlling each of the first, second and third pixel sub-components separately with respective luminous intensity values, the first, second and third pixel sub-components of the pixel Each rather than the entire pixel represents a different part of the image. 9. The method of claim 8, wherein the act of displaying an image results in a text character having a portion in a direction perpendicular to the strip whose value is not in a direction perpendicular to the strip Dimensions that are integer multiples of the pixel scale value. 10. The method of claim 9, wherein the portion of the text character is a stem of the text character, and the size of the stem is not an integer multiple of the pixel width. 11. The method of claim 9, wherein the display device comprises a liquid crystal display; and the first, second and third pixel sub-components have red, green and blue colors, respectively. 12. The method of claim 8, further comprising prior to the act of sampling the information, causing the information representing the image to be larger in a direction perpendicular to the stripes than in a direction parallel to the stripes A factor that scales the action. 13. The method of claim 8, further comprising the act of performing a color processing operation on the information representing the image, the color processing operation compensating for when different sets of one or more samples are mapped to the first, The second and third pixel subcomponents are the color distortions that have been introduced into the information. 14. A computer program product for implementing a method for improving the resolution of a displayed image in a computer system comprising a processing unit and a display device for displaying the image, said display device having a plurality of pixels each comprising at least Three pixel subcomponents, each pixel subcomponent having a different color, characterized in that the computer program product comprises: A computer-readable medium carrying executable instructions for performing the method, wherein the method comprises the steps of: Maps a sample of information representing an image to individual pixel subcomponents of a pixel, rather than mapping the sample to the entire pixel, to which each pixel subcomponent has mapped a set of spatially distinct one or more samples, pixel sub-components of a plurality of pixels are arranged to form a strip of pixel sub-components of the same color on the display device; generating separate luminous intensity values for each pixel subcomponent of the pixel based on the different sets of one or more samples mapped thereto; and The image is displayed on the display device using separate luminous intensity values, resulting in each pixel sub-component of the pixel representing a different portion of the image rather than the entire pixel. 15. The computer program product according to claim 14, wherein said method further comprises the step of: prior to the step of mapping the samples, causing the information representative of the image to be larger in a direction perpendicular to the strip than in a direction parallel to The direction of the strips should be scaled by a large factor. 16. The computer program product of claim 14, wherein said executable instructions perform the step of mapping samples such that each pixel subcomponent of a pixel has one of the samples mapped thereto and just one. 17. The computer program product of claim 14, wherein the executable instructions perform the step of mapping samples such that at least one of the pixel subcomponents of the pixel has mapped two of the samples to it. or more. 18. The computer program product of claim 14, wherein the executable instructions map a different number of samples to each pixel subcomponent of a pixel. 19. The computer program product of claim 14, wherein the information representative of the image includes an outline of the image, with a foreground color and a background color associated therewith. 20. The computer program product of claim 14, wherein the step of generating light intensity values for each pixel subcomponent includes one or more values based on the relative position of the image and mapped to the pixel subcomponent. The sampled group selection turns on or off the step of the light intensity value. 21. A computer program product implementing a method for improving the resolution of a displayed image in a computer system comprising a processing unit and a display device for displaying the image, said display device having a plurality of pixels each comprising at least Three pixel sub-components, each pixel sub-component has a different color, the at least three pixel sub-components include a first pixel sub-component, a second pixel sub-component and a third pixel sub-component, characterized in In that said computer program product includes: A computer-readable medium carrying executable instructions for performing the method, wherein the method includes the acts of: Acquiring information representing an image, thereby obtaining multiple samples; mapping a first set of one or more samples to a first pixel sub-component of a pixel of a display device, the pixel sub-components of a plurality of pixels of the display device being arranged to form pixel sub-components of the same color on the display device Bands; mapping a second set of one or more samples to a second pixel subcomponent of the pixel; mapping a third set of one or more samples to a third pixel subcomponent of a pixel, wherein the first, second, and third sets are spatially distinct from each other; For each of the first, second, and third pixel subcomponents, generating a respective luminous intensity value based on the particular set of one or more samples mapped thereto; and An image is displayed on a display device by controlling each of the first, second and third pixel sub-components separately with respective luminous intensity values, the first, second and third pixel sub-components of the pixel Each rather than the entire pixel represents a different part of the image. 22. The computer program product of claim 21 , wherein the act of displaying an image results in a text character having a portion in a direction perpendicular to the stripe whose value is not in a direction perpendicular to the stripe Dimensions that are integer multiples of the pixel scale value in the direction. 23. The computer program product of claim 22, wherein the portion of the text character is a stem of the text character, and the size of the stem is not an integer multiple of the pixel width. 24. The computer program product of claim 22, wherein the display device comprises a liquid crystal display; the first, second and third pixel sub-components have red, green and blue colors, respectively. 25. The computer program product of claim 21 , wherein the method further comprises, prior to the act of sampling the information, causing the information representing the image to move in a direction perpendicular to the stripes more than parallel to the stripes. The action is scaled by a larger factor in the direction of . 26. The computer program product of claim 21, wherein the method further comprises the act of performing a color processing operation on the information representing the image, the color processing operation compensating for when different groups of one or more samples are The color distortion that has been introduced into the information when mapping to the first, second and third pixel sub-components. 27. A display device for use with a computer system comprising a processing unit and a memory device, the display device being capable of displaying images and comprising: A plurality of pixels, each pixel comprising at least three pixel sub-components, each pixel sub-component having a different color, the pixel sub-components of the plurality of pixels are arranged to form the same color pixel sub-components on a display device strips; and A computer program product comprising a computer readable medium carrying executable instructions which, when stored in said memory means, causes said computer system to implement a method for improving the resolution of a displayed image, said method comprising The following steps: Maps a sample of information representing an image to individual pixel subcomponents of a pixel, rather than mapping the sample to the entire pixel, to which each pixel subcomponent has mapped a set of spatially distinct one or more samples; generating separate luminous intensity values for each pixel subcomponent of the pixel based on the different sets of one or more samples mapped thereto; and The image is displayed on the display device using separate luminous intensity values, resulting in each pixel sub-component of the pixel representing a different portion of the image rather than the entire pixel. 28. The display device of claim 27, wherein the display device comprises a liquid crystal display having a plurality of pixels. 29. The display device of claim 28, wherein the at least three pixel subcomponents of each of the plurality of pixels comprise a red pixel subcomponent, a green pixel subcomponent, and a blue pixel subcomponent , each of which is controlled separately. 30. The display device of claim 28, further comprising displayed text characters constituting at least a portion of the image, said text characters being displayed on the display device as a result of the step of displaying the image. 31. The display device according to claim 30, wherein a portion of the text characters has a size in a direction perpendicular to the strip whose value is not an integer multiple of the pixel scale value in the direction perpendicular to the strip . 32. The display device according to claim 31, wherein the part of the text characters is a stem of the text character; the width of the stem is not an integer multiple of the pixel width. 33. A display device for use with a computer system comprising a processing unit and a memory device, the display device being capable of displaying images and comprising: A plurality of pixels, each pixel including at least three pixel sub-components each having a different color, including a first pixel sub-component, a second pixel sub-component and a third pixel sub-component, the plurality of pixels the pixel sub-components are arranged to form stripes of like-colored pixel sub-components on the display device; and A computer program product comprising a computer readable medium carrying executable instructions which, when stored in said memory means, causes said computer system to implement a method for improving the resolution of a displayed image, said method comprising The following actions: Acquiring information representing an image, thereby obtaining multiple samples; mapping the first set of one or more samples to a first pixel subcomponent of a pixel of the display device; mapping a second set of one or more samples to a second pixel subcomponent of the pixel; mapping a third set of one or more samples to a third pixel subcomponent of said pixel, wherein the first, second, and third sets are spatially distinct from each other; For each of the first, second, and third pixel subcomponents, generating a respective luminous intensity value based on the particular set of one or more samples mapped thereto; and An image is displayed on a display device by controlling each of the first, second and third pixel sub-components separately with respective luminous intensity values, the first, second and third pixel sub-components of the pixel Each rather than the entire pixel represents a different part of the image. 34. The display device of claim 33, wherein the display device comprises a liquid crystal display having a plurality of pixels. 35. The display device as claimed in claim 34, wherein the first, second and third pixel sub-components respectively comprise a red pixel sub-component, a green pixel sub-component and a blue pixel sub-component , each of which is controlled separately. 36. The display device of claim 34, further comprising displayed text characters forming part of the displayed image. 37. The display device as claimed in claim 36, wherein a portion of the text characters has a size in a direction perpendicular to the strip whose value is not an integer multiple of the pixel scale value in the direction perpendicular to the strip . 38. The display device according to claim 37, wherein the part of the text characters is a stem of the text character; the width of the stem is not an integer multiple of the pixel width.

Images