Computer graphics processing and selective visual display system – Computer graphics processing – Character generating
Reexamination Certificate
1998-12-04
2001-10-02
Brier, Jeffery (Department: 2672)
Computer graphics processing and selective visual display system
Computer graphics processing
Character generating
C345S156000, C345S156000, C345S156000, C345S426000
Reexamination Certificate
active
06297829
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an image processing apparatus, an image output device and an image processing method respectively for visually smoothing ridges on the edge if necessary when a character, a line and others are output and a record medium on which an image processing program for instructing a computer to execute the image processing is recorded. Further, the present invention also relates to color facsimile machines, or to transmission/reception of images of the Internet.
Generally, if code image data such as a page description language (PDL) is used, image data such as a photograph and an image in which a line, a character and others are mixed can be output to different types of terminals by a common output device and can be output to different output devices in common. Therefore, code image data is widely used in outputting an image.
As an area in which such code image data is plotted is defined by vector data and outline data in various plotting instructions as well-known, the contents of code image data are required to be interpreted and to be expanded (converted) to plotted pattern data which is image data when the code image data is output to a printer, a display and others.
A case that a straight line shown in
FIG. 16A
is formed by code image data will be examined below. In this case, when binarization processing is executed for the following picture element if an area to be plotted is overlapped with a part of a picture element, ridges are remarkable on the edge of a line formed by the plotted pattern data as shown in FIG.
16
B.
When a character and a line are output, smoothing processing for visually smoothing ridges is applied.
When for an example of the processing, a case that a picture element encircled as shown in
FIG. 16A
is in a state shown in
FIG. 16C
is explained, first, the picture element is divided into plural (for example,
16
) subpixels as shown in FIG.
16
D. Second, if an area to be plotted accounts for a half of the area of the subpixels or more, a pixel value ‘1’ is given to the subpixels as shown in
FIG. 16E
, however, in the meantime, if the area does not account for a half or more, a pixel value ‘0’ is given to the subpixels. There are various methods in judgment for giving a pixel value. Third, the total pixel values of the divided subpixels are equivalent to the multivalued pixel value of the picture element. In the example shown in
FIG. 16E
, the pixel value of the picture element is multivalued as ‘10’.
As a picture element on the edge is a halftone between an area to be plotted and an area not plotted when a picture element of a character, a line and others is multivalued as described above, ridges are visually inhibited.
In the example shown in
FIGS. 16D and 16E
, as a picture element is divided into 16 subpixels, a gradient by multivaluing is 17 gradations of zero to 16 and the gradient can be increased by dividing into further multiple subpixels.
In the Unexamined Japanese Patent Application Publication No. Hei 4-195268, technique for optimizing the shape of a subpixel, the number of divided subpixels and others according to the gradient of vector data in multivaluing is disclosed. According to this technique, ridges can be also made inconspicuous.
As described above, the quality of output vector data in code image data can be enhanced by arranging multivalued pixels on the edge.
However, to expand vector data to multivalued plotted pattern data, the vector data is required to be expanded at higher resolution than the resolution of output equipment and to be temporarily stored because a picture element is divided into subpixels. Therefore, there is a problem that a bulk memory is required, compared with a case that no smoothing processing is executed and further, processing time is also extended.
A case that a thin line is formed, compared with the size of one picture element as shown in
FIG. 17A
will be examined below. In this case, binarization processing in which if an area to be plotted is overlapped with a part of a picture element, ‘1’ is given to the picture element or if an area to be plotted is overlapped with the center of a picture element, ‘1’ is given to the picture element is executed, a result shown in
FIG. 17B
is obtained.
In the meantime, when the above multivaluing processing is executed for the line shown in
FIG. 17A
, a pixel value becomes very small and the density of an output line is reduced as a result.
Therefore, depending upon a case, binarization processing may be more excellent than multivaluing processing as a result in the aspect of the quality of output, recognition in optical reading and others.
In the example shown in
FIGS. 17
, a pixel value ‘1’ in the case of binarization processing is equivalent to a pixel value ‘16’ in the case of multivaluing processing and in both cases, the density of a corresponding picture element is 100%.
SUMMARY OF THE INVENTION
The present invention is made to solve the above problem and the object is to reduce processing time without requiring a bulk memory by executing smoothing processing if necessary when code image data is expanded to plotted pattern data and to provide an image processing apparatus wherein ridges are inconspicuous and a high quality of plotting pattern can be generated, an image output device wherein the output of an image is enabled, an image processing method and further, a record medium on which an image processing program for instructing a computer to execute the image processing is recorded.
To achieve the above object, an image processing apparatus according to the present invention is based upon an image processing apparatus for expanding code image data to plotted pattern data and characterized in that first expansion means for expanding code image data to binarized plotted pattern data, second expansion means for expanding code image data to multivalued plotted pattern data and selection means for selecting and applying either the above first or second expansion means as expansion means for expanding code image data are provided.
According to the present invention, although ridges on the edge of a character, a line and others may be conspicuous when code image data in which an instruction for plotting a character, a line and others is described is interpreted and expanded to plotted pattern data which is its bit image, either the first expansion means by which processing is executed at high speed or the second expansion means by which the edge of a character, a line and others is visually smoothed by multivaluing is suitably selected and applied according to a situation.
For the criterion of judgment for selection, if a line is output, the length, the width, an angle and others are conceivable. The reason is that as the smaller either the length of the line or the width is, compared with a picture element or the closer to level or a perpendicular the angle of the line is, the more conspicuous ridges on the edge are, expansion means used for expansion processing is required to be suitably selected according to the width and the angle of the line.
Also, for the criterion of judgment for selection, if a character is output, the typeface, the size, a character code and others are suitable. Because it is determined according to these individual conditions whether ridges are conspicuous on the edge of a character or not.
In the meantime, it is required to be considered that processing speed may be given priority over the quality of output. In this case, as time required for processing by the second expansion means is longer, compared with that by the first expansion means, a desirable result can be obtained if time required for processing by the former is estimated and expansion means used for expansion processing is selected based upon a result of the estimate.
Further, for the criterion of judgment for selection, judgment by a user is also important. Therefore, it is desirable that a user himself/herself can select expansion means used for expansion processing.
REFERENCES:
patent: 5294918 (1
Kawano Hiroyuki
Sekine Hiroshi
Tsukimura Shigeru
Brier Jeffery
Fuji 'Xerox Co., Ltd.
Good-Johnson Motilewa
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