Image analysis – Image transformation or preprocessing – Changing the image coordinates
Reexamination Certificate
1999-07-30
2001-08-28
Bella, Matthew C. (Department: 2621)
Image analysis
Image transformation or preprocessing
Changing the image coordinates
C382S203000, C382S256000, C345S469000, C345S472000
Reexamination Certificate
active
06282327
ABSTRACT:
§ 1. BACKGROUND OF THE INVENTION
§ 1.1 Field of the Invention
The present invention concerns techniques for enhancing the resolution of characters, such as fonts for example, to be rendered on a patterned output device, such as a flat panel video monitor or an LCD video monitor for example. More specifically, the present invention concerns techniques for maintaining the width of fonts, and related challenges, so that existing formatting remains unchanged when the resolution of characters is enhanced. The present invention also concerns minimizing visually annoying variations in spacing and line weight.
§ 1.2 Related Art
Before an introduction of related art, it must be understood that the related art described here is not necessarily “prior art” and that the description of such related art in this section is not to be construed as an admission that the art is “prior art”, unless expressly stated.
The present invention may be used in the context of patterned output devices such as flat panel video monitors, or LCD video monitors for example. In particular, the present invention may be used as a part of processing to produce higher resolution characters, such as text for example, on patterned displays, such as LCD video monitors for example. Although the structure and operation of display devices in general, and patterned display devices, such as LCD monitors for example, in particular, are known by those skilled in the art, they are discussed in § 1.2.1 below for the reader's convenience. Then, known ways of rendering characters on such displays are discussed in § 1.2.2 below.
§ 1.2.1 Display Devices
Color display devices have become the principal display devices of choice for most computer users. Color is typically displayed on a monitor by operating the display device to emit light (such as a combination of red, green, and blue light for example) which results in one or more colors being perceived by the human eye.
Although color video monitors in general, and LCD video monitors in particular, are known to those skilled in the art, they are introduced below for the reader's convenience. In § 1.2.1.1 below, cathode ray tube (or CRT) video monitors are first introduced. Then, in § 1.2.1.2 below, LCD video monitors are introduced.
§ 1.2.1.1 CRT Video Monitors
Cathode ray tube (CRT) display devices include phosphor coatings which may be applied as dots in a sequence on the screen of the CRT. A different phosphor coating is normally associated with the generation of different colors, such as red, green, and blue for example. Consequently, repeated sequences of phosphor dots are defined on the screen of the video monitor. When a phosphor dot is excited by a beam of electrons, it will generate its associated color, such as red, green and blue for example.
The term “pixel” is commonly used to refer to one spot in a group of spots, such as rectangular grid of thousands of such spots for example. The spots are selectively activated to form an image on the display device. In most color CRTs, a single triad of red, green and blue phosphor dots cannot be uniquely selected. Consequently, the smallest possible pixel size will depend on the focus, alignment and bandwidth of the electron guns used to excite the phosphor dots. The light emitted from one or more triads of red, green and blue phosphor dots, in various arrangements known for CRT displays, tend to blend together giving, at a distance, the appearance of a single colored light source.
In color displays, the intensity of the light emitted from the additive primary colors (such as red, green, and blue) can be varied to achieve the appearance of almost any desired color pixel. Adding no color, i.e., emitting no light, produces a black pixel. Adding 100 percent of all three (3) colors produces a white pixel.
Having introduced color CRT video monitors, color LCD video monitors are now introduced in § 1.2.1.2 below.
§ 1.2.1.2 LCD Video Monitors
Portable computing devices (also referred to generally as computing appliances or untethered computing appliances) often use liquid crystal displays (LCDs) or other flat panel display devices, instead of CRT displays. This is because flat panel displays tend to be smaller and lighter than CRT displays. In addition, flat panel displays are well suited for battery powered applications since they typically consume less power than comparably sized CRT displays. Further, LCD flat panel monitors are even becoming more popular in the desktop computing environment.
Color LCD displays are examples of display devices which distinctly address elements (referred to herein as pixel sub-components, pixel sub-elements, or simply, emitters) to represent each pixel of an image being displayed. Normally, each pixel element of a color LCD display includes three (3) non-square elements. More specifically, each pixel element may include adjacent red, green and blue (RGB) pixel sub-components. Thus, a set of RGB pixel sub-components together may define a single pixel element.
Known LCD displays generally include a series of RGB pixel sub-components which are commonly arranged to form stripes along the display. The RGB stripes normally run the entire length of the display in one direction. The resulting RGB stripes are sometimes referred to as “RGB striping”. Common LCD monitors used for computer applications, which are wider than they are tall, tend to have RGB vertical stripes. Naturally, however, some LCD monitors may have RGB horizontal stripes.
FIG. 1
illustrates a known LCD screen
100
comprising pixels arranged in a plurality of rows (R1-R12) and columns (C1-C16). That is, a pixel is defined at each row-column intersection. Each pixel includes a red pixel sub-component, depicted with moderate stippling, a green component, depicted with dense stippling, and a blue component, depicted with sparse stippling.
FIG. 2
illustrates the upper left hand portion of the known display
100
in greater detail. Note how each pixel element, such as, the (R2, C4) pixel element for example, comprises three (3) distinct sub-element or sub-components; a red sub-component
206
, a green sub-component
207
and a blue sub-component
208
. In the exemplary display illustrated, each known pixel sub-component
206
,
207
,
208
is ⅓, or approximately ⅓, the width of a pixel while being equal, or approximately equal, in height to the height of a pixel. Thus, when combined, the three ⅓ width, full height, pixel sub-components
206
,
207
,
208
define a single pixel element.
As illustrated in
FIG. 1
, one known arrangement of RGB pixel sub-components
206
,
207
,
208
form what appear to be vertical color stripes on the display
100
. Accordingly, the arrangement of ⅓ width color sub-components
206
,
207
,
208
, in the known manner illustrated in
FIGS. 1 and 2
, exhibit what is sometimes called “vertical striping”.
In known systems, the RGB pixel sub-components are generally used as a group to generate a single colored pixel corresponding to a single sample of the image to be represented. More specifically, in known systems, luminous intensity values for all the pixel sub-components of a pixel element are generated from a single sample of the image to be rendered.
Having introduced the general structure and operation of known LCD displays, known techniques for rendering text on such LCD displays, as well as perceived shortcomings of such known techniques, are introduced in §1.2.2 below.
§ 1.2.2 Rendering Text on Displays
The expression of textual information using font sets is introduced in § 1.2.2.1 below. Then, the rendering of textual information using so-called pixel precision and perceived shortcomings of doing so are introduced in § 1.2.2.2 below.
§ 1.2.2.1. Font Sets
A “font” is a set of characters of the same typeface (such as Times Roman, Courier New, etc.), the same style (such as italic), the same weight (such as bold and, strictly speaking, the same size). Characters may include symbols, such as the “Parties MT”, “Webdings”, and “Wingdings” symbol groups found on the Word™ word
Betrisey Claude
Dresevic Bodin
Bella Matthew C.
Desire Gregory
Microsoft Corporation
Workman & Nydegger & Seeley
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