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Claims  |
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I claim:
1. A method of generating an integrated image including plural types of
image elements on an image plane comprising a two-dimensional array of
pixels, comprising the steps of:
(a) obtaining respective image data representing respective image elements
in respective resolutions and in respective data length for each pixel;
(b) designating positions of said image elements on said image plane;
(c) dividing said image plane into a plurality of regions
(d) selecting one of said plurality of regions to obtain a selected region;
(e) determining what types of image elements are included in said selected
region, to thereby specify objective image elements;
(f) determining maximum resolution and maximum data length within
respective resolutions and data lengths of said objective image elements;
(g) integrating on said selected region said objective image elements in
said maximum resolution and in said maximum data length to obtain a part
of an integrated image data representing a part of said integrated image
defined on said selected region; and
(h) repeating the steps (d) through (g) while serially changing said
selected region within said plurality of regions, to thereby obtain
integrated image data representing the whole of said integrated image on
said image plane.
2. The method of claim 1, further comprising the step of:
(i) prior to the step (a), determining a plurality of image-integration
modes characterized by different resolutions and different data length;
wherein the step (g) comprises the steps of:
(g-1) selecting one of said plurality of image-integration modes in
accordance with said maximum resolution and said maximum data length, to
thereby specify a selected image-integration mode; and
(g-2) integrating on said selected region said objective image elements in
said selected image-integration mode to obtain said part of said
integrated image data.
3. The method of claim 2, wherein
said image elements are classified into a plurality of image types
including multi-tone image type and binary image type; and the step (i)
comprises the steps of:
(i-1) determining a first image-integration mode characterized by a first
resolution and a first data length for each pixel;
(i-2) determining a second image-integration mode characterized by a second
resolution and a second data length for each pixel; and
(i-3) determining a third image-integration mode characterized by a third
resolution and a third data length for each pixel,
wherein each of said first and third resolutions are higher than said
second resolution; and
each of said second and third data length are longer than said first data
length.
4. The method of claim 3, wherein
said image elements of said multi-tone image type include a picture image
element representable in said second resolution and said second data
length for each pixel; and
said image elements of said binary image type include at least one of a
character image element and a diagram image element representable in said
first resolution and said first data length for each pixel.
5. The method of claim 4, further comprising the step of:
(j) converting said integrated image data into a binarized and integrated
image data representing said integrated image in binary dots.
6. The method of claim 5, wherein
the step (j) comprises the step of:
(j-1) with respect to a part of said integrated image obtained through
either of said second and third image-integration modes, comparing said
integrated image data with threshold values to generate halftone dot image
data representing a halftone dot image as a part of said binarized and
integrated image data.
7. The method of claim 6, wherein
the step (j1) comprises the step of:
with respect to a part of said integrated image obtained through said
second image-integration mode, comparing said integrated image data with
said threshold values while assigning said integrated image data to a
plurality of pixels each having a size previously determined in accordance
with recording resolution in an image recording device.
8. The method of claim 7, further comprising the step of:
(k) prior to the step (a), preparing a plurality of image frame memory
means;
wherein the step (g) further comprises the steps of;
(g-3) designating one of said plurality of image frame memory means to
specify an objective image frame memory mean; and
(g-4) storing said part of an integrated image data in said objective image
frame memory means.
9. The method of claim 8, wherein
the step (g) further comprises the step of;
(g-5) changing designation of said objective image frame memory means every
time when said image-integration mode selected in the step (g-1) for a
currently selected region is different from that for a region selected in
a previous repetition in the step (h).
10. The method of claim 9, wherein
the step (g) further comprises the step of;
(g-6) changing said designation of said objective image frame memory means
to another image frame memory means among said plurality of image frame
memory means every time when said objective image frame memory means is
filled with parts of said integrated image data.
11. The method of claim 10, wherein
the step (c) comprises the step of;
(c-1) dividing said image plane into a plurality of rectangular strip
regions regardless of said positions of said image elements on said image
plane.
12. The method of claim 10, wherein the step (c) comprises the step of;
(c-1) dividing said image plane into a plurality of areas in accordance
with distribution of said image elements on said image plane.
13. The method of claim 1, wherein said step (f) comprises determining the
maximum resolution and maximum data length within respective resolutions
and data lengths of said objective image elements in said selected region.
14. An apparatus for generating an integrated image including a plural
types of image elements on an image plane including a two-dimensional
array of pixels, comprising
(a) means for inputting: respective image data representing image elements
in respective resolutions and in respective data length for each pixel;
and positions of said image elements on said image plane;
(b) means for dividing said image plane into a plurality of regions;
(c) means for serially selecting one of said plurality of regions to obtain
a selected region;
(d) means for determining what types of image elements are included in said
selected region, to thereby specify objective image elements;
(e) means for determining maximum resolution and maximum data length within
respective resolutions and data lengths of said objective image elements;
(f) processor means for integrating on said selected region said objective
image elements in said maximum resolution and in said maximum data length
to obtain a part of an integrated image data representing a part of said
integrated image defined on said selected region;
(g) memory means for storing respective parts of an integrated image data;
and
(h) means for reading said respective parts of an integrated image data out
of said memory means to output said respective parts of said integrated
image data.
15. The apparatus of claim 14, wherein
said processor means comprises:
(f-1) means for holding procedures for a plurality of image-integration
modes characterized by different resolutions and different data length;
(f-2) means for selecting one of said plurality of image-integration modes
in accordance with said maximum resolution and said maximum data length,
to thereby specify a selected image-integration mode; and
(f-3) means for integrating on said selected region said objective image
elements in said selected image-integration mode to obtain said part of
said integrated image data.
16. The apparatus of claim 15, wherein said image elements are classified
into a plurality of image types including multi-tone image type and binary
image type; and
said plurality of said image-integration modes includes:
a first image-integration mode characterized by a first resolution and a
first data length for each pixel;
a second image-integration mode characterized by a second resolution and a
second data length for each pixel; and
a third image-integration mode characterized by a third resolution and a
third data length for each pixel
wherein each of said first and third resolutions are higher than said
second resolution; and
each of said second and third data lengths are longer than said first data
length.
17. The apparatus of claim 16, wherein
said image elements of said multi-tone image type include a picture image
element representable in said second resolution and said second data
length for each pixel; and
said image elements of said binary image type include at least one of a
character image element and a diagram image element representable in said
first resolution and said first data length for each pixel.
18. The apparatus of claim 17, further comprising:
(i) means for converting said integrated image data into a binarized and
integrated image data representing said integrated image in binary dots.
19. The apparatus of claim 18, wherein said means (i) comprises:
(i-1) means for, with respect to a part of said integrated image obtained
through either of said second and third image-integration modes, comparing
said integrated image data with threshold values to generate halftone dot
image data representing a halftone dot image as a part of said binarized
and integrated image data.
20. The apparatus of claim 19, wherein said means (i-1) comprises:
means for, with respect to a part of said integrated image obtained through
said second image-integration mode, comparing said integrated image data
with said threshold values while assigning said integrated image data to a
plurality of pixels each having a size previously determined in accordance
with resolution in an image recording device.
21. The apparatus of claim 20, wherein
said memory means comprises:
(g-1) a plurality of image frame memory means; and
said apparatus further comprises:
(j) means for designating one of said plurality of image frame memory means
to store said part of an integrated image data in said one said plurality
of image frame memory means to specify an objective image frame memory
means.
22. The apparatus of claim 21, wherein
said means (j) comprises;
(j-1) means for changing designation of said objective image frame memory
means every time when said image-integration mode selected in said means
(f-1) for a currently selected region is different from that for a region
selected just before said currently selected region.
23. The apparatus of claim 22, wherein
said means (j) further comprises;
(j-2) means for changing said designation of said objective image frame
memory means every time when said objective memory means is filled with
parts of said integrated image data.
24. The apparatus of claim 23, wherein
said means (b) comprises;
(b-1) means for dividing said image plane into a plurality of rectangular
strip regions regardless of said positions of said image elements on said
image plane.
25. The apparatus of claim 23, wherein said means (b) comprises;
(b-1) means for inputting data for dividing said image plane into a
plurality of areas in accordance with distribution of said image elements
on said image plane.
26. The apparatus of claim 14, wherein said means for determining maximum
resolution and maximum data length comprises means for determining the
maximum resolution and maximum data length within respective resolutions
and data lengths of said objective image elements in said selected region. |
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Claims |
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Description |
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method and an apparatus for generating
an image data representing an integrated image, and more particularly, to
an improvement in integrating respective images of a character, diagram
and a picture to generate a halftone dot image data or a binary image data
of an integrated image and deliver the same to an output device such as an
image scanner.
2. Description of the Background Art
Some current personal computers and work stations are capable of generating
an image including characters, diagrams and pictures and transforming the
image into a page description language. Such an image is called an
"integrated image". Page description language is a language for describing
shapes, colors and locations of the characters, diagrams and pictures in
accordance with a specific program grammar and an example thereof is a
language "Post Script". A program described in a page description language
is called "image description program" hereinafter.
FIG. 6 is a block diagram showing an image processing system for generating
an image in accordance with an image description program. The image
processing system comprises a host processor 10, an image integrating
device 20 and an output device 30.
The host processor 10 receives an image description program P.sub.i, a
multi-tone image data D.sub.i expressing multi-tone image of a picture and
the like through an external interface 13 from an external device (not
shown) and decodes the image description program P.sub.i to produce vector
data V.sub.l and V.sub.f expressing characters and diagrams, respectively.
To the host processor 10, a character font disc 11 for storing character
fonts and an image data memory 12 for temporarily storing a multi-tone
image data are connected.
The vector data V.sub.l and V.sub.f and the multi-tone image data D.sub.i
are transmitted from the host processor 10 to data management unit 21 in
the image integrating device 20. The data management unit 21 has a
function to control the whole operation of the image integrating device
20.
The vector data V.sub.l and V.sub.f and the multi-tone image data D.sub.i
are delivered from the data management unit 21 to the data processing unit
22. The data processing unit 22 performs a coordinate transformation with
regard to these data, and additionally, it transforms the vector data
V.sub.l and V.sub.f into a raster data R.sub.l and R.sub.f, respectively.
The raster data R.sub.l and R.sub.f and the multi-tone image data D.sub.ia
obtained in the data processing unit 22 are supplied to a dot generator (a
halftone dot image generating unit) 23 and transformed into a halftone
image data D.sub.h. The halftone dot image data D.sub.h expresses
respective ON/OFF states of halftone dots, in which a single bit is
asssigned to each dot cell in each color component. The "dot cell" is
respective ones of unit areas forming one halftone dot and the color
component is respective ones of R (red), G (green) and B (blue), for
example.
The halftone dot data D.sub.h is temporarily stored in an output frame
memory 24 in which 1 bit is assigned to each dot cell in each color
component, and thereafter, it is outputted to an output device 30 to
display or record an integrated halftone dot image.
In the conventional image integrating device 20, the character raster data
R.sub.l, the diagram raster data R.sub.f and the multi-tone image data
D.sub.ia are separately applied to the dot generator 23, and then a data
processing to produce the halftone dot data D.sub.h is performed. For this
reason, all of the data R.sub.l, R.sub.f and D.sub.ia are processed under
the common condition where resolution is set at the highest resolution in
respective data R.sub.l, R.sub.f and D.sub.ia and number of gradation
levels is set at the maximum number of gradation levels in respective data
R.sub.l, R.sub.f and D.sub.ia. The maximum number of gradation levels is
the maximum one of respective numbers of bits expressing optical density
levels in the data R.sub.l, R.sub.f and D.sub.ia, for example.
Thus, an efficiency of processing the image data is not necessarily high
and there arises the problem that the processing is slow or an efficiency
in using an output frame memory is low.
The dot generator 23 generates the halftone dot data D.sub.h by comparing
optical density levels of the pixels expressed by the data R.sub.l,
R.sub.f and D.sub.ia, respectively, with threshold values or screen
pattern data for each pixel in each scanning line. The screen pattern data
is previously stored in the dot generator 23. Now then, regions to which
characters, diagrams and pictures to be allocated on an imaging plane are
often not rectangular. In the prior art, in order to produce a halftone
dot data on a region that is not rectangular, it is required that the head
coordinates on an image plane in respective main scanning lines in the
region is transformed into addresses of the screen pattern data or
coordinates on a screen pattern plane, and the screen pattern data is read
in accordance with the address. Such a transformation processing is a very
complex one, and thus, there arises the problem that a processing speed is
lowered in the dot generator 23.
SUMMARY OF THE INVENTION
The present invention is directed to a method of generating an integrated
image including plural types of image elements.
According to the present invention, the method comprises the steps of: (a)
obtaining respective image data representing respective image elements in
respective resolutions and in respective data length for each pixel; (b)
designating positions of the image elements on an image plane on which an
integrated image is to be defined; (c) dividing the image plane into a
plurality of regions; (d) selecting one of the plurality of regions to
obtain a selected region; (e) determining what image elements are included
in the selected region, to thereby specify objective image elements; (f)
determining maximum resolution and maximum data length within respective
resolutions and data length of the objective image elements; (g)
integrating on the selected region the objective image elements in the
maximum resolution and in the maximum data length to obtain a part of an
integrated image data representing a part of the integrated image defined
on the selected region; and (h) repeating the steps (d) through (g) while
serially changing the selected region within the plurality of regions, to
thereby obtain the integrated image data representing the whole of the
integrated image on the image plane.
Preferably, the method further comprising the step of: (i) prior to the
step (a), determining a plurality of image-integration modes characterized
by different resolutions and different data length.
In accordance with the step (i), the step (g) comprises the steps of: (g-1)
selecting one of the plurality of image-integration modes in accordance
with the maximum resolution and the maximum data length, to thereby
specify a selected image-integration mode; and (g-2) integrating on the
selected region the objective image elements in the selected
image-integration mode to obtain the part of the integrated image data.
The image elements may be classified into a plurality of image types
including multi-tone image type and binary image type.
The plurality of image-integration modes may include first through third
image-integration modes. The first image-integration mode is characterized
by relatively high resolution and relatively small data length for each
pixel, while the second image-integration mode is characterized by
relatively low resolution and relatively large data length for each pixel.
Further, the third image-integration mode is characterized by relatively
high resolution and relatively large data length for each pixel.
The present invention is also directed to an apparatus for generating an
integrated image including a plural types of image elements.
According to the present invention, the apparatus comprises: (a) means for
inputting: respective image data representing image elements in respective
resolutions and in respective data length for each pixel; and positions of
the image elements on an image plane on which an integrated image is to be
defined; (b) means for dividing the image plane into a plurality of
regions; (c) means for serially selecting one of the plurality of regions
to obtain a selected region; (d) means for determining what image elements
are included in the selected region, to thereby specify objective image
elements; (e) means for determining maximum resolution and maximum data
length within respective resolutions and data length of the objective
image elements; (f) processor means for integrating on the selected region
the objective image elements in the maximum resolution and in the maximum
data length to obtain a part of an integrated image data representing a
part of the integrated image defined on the selected region; (g) memory
means for storing respective parts of an integrated image data; and (h)
means for reading the respective parts of an integrated image data out of
the memory means to output the respective parts of the integrated image
data.
The memory means may include a plurality of image frame memories used for
storing respective parts of the integrated image data obtained through
different image-integration modes.
Since image-integration on respective regions on the image plane are
carried out in respective optimum modes, the efficiency in the
image-integration is improved.
Accordingly, an object of the present invention is to generate an
integrated image of characters, diagrams and pictures at a high
efficiency.
Another object of the present invention is to generate a halftone dot image
without a complex transformation processing of coordinates in a dot
generator even if respective image regions are not rectangular.
These and other objects, features, aspects and advantages of the present
invention will become more apparent from the following detailed
description of the present invention when taken in conjunction with the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram showing an image processing system comprising an
image integrating device according to a preferred embodiment of the
present invention;
FIGS. 2 and 5 are conceptual diagrams showing a method of dividing a
halftone dot image;
FIGS. 3(a) through 3(c) are conceptual diagrams showing the size of a pixel
and the data length of an image data for one pixel in respective
processing modes;
FIGS. 4(a) through 4(c) are diagrams showing the dimensions of an image
which can be accommodated in a single image frame memory in respective
processing modes; and
FIG. 6 is a block diagram showing a conventional image processing system.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 is a block diagram showing an image processing system comprising an
image integrating device 200 according to a preferred embodiment of the
present invention. In addition to the image integrating device 200, the
image processing system has a host processor 10, a character font disc 11,
an image data memory 12 and an output device 30.
The image integrating device 200 has a data management unit 21, an image
processing unit 220, a dot generator 23 and an output frame memory 24. The
image processing unit 220 has three image processing modules 220a through
220c. Furthermore, the image processing modules 220a through 220c have
data processing units 22a through 22c and image frame memories 25a through
25c, respectively.
In those components, the image frame memories 25a through 25c are elements
characterizing the present invention. The image frame memories 25a through
25c are memories for storing image data of a binary high resolution image
and a multivalued high resolution image in accordance with a selected mode
mentioned later, each of which memories has a capacity of 8 MB (mega
bites) or 8.times.8=64 mega bits, for example. The capacity of each memory
25a, 25b, 25c is represented by a symbol A.sub.t (not shown in the
drawings). Details of the memories 25a-25c will be described later.
As the host processor 10, a so-called engineering work station and a
personal computer may be employed. The host processor 10, as in the prior
art, receives an image description program P.sub.i and multi-tone image
data D.sub.i from an external device through an external interface 13. The
image description program P.sub.i represents characters and diagrams,
while the multi-tone image data D.sub.i represents multi-tone pictures.
Respective positions of the characters, the diagrams and the pictures on
an image plane may be designated in the image description program P.sub.i
and the multi-tone image data D.sub.i, or alternatively, they may be
designated by inputting another data defining them. The characters, the
diagrams and the pictures are image elements to be integrated on the image
plane.
The host processor 10 decodes the image description program P.sub.i to
obtain a character vector data V.sub.l and a diagram vector data V.sub.f
and temporarily stores multi-tone image data D.sub.i in the image data
memory 12. Characters in the image description program P.sub.i are
designated in the form of character font codes, and therefore, the host
processor 10 produces the character vector data V.sub.l based upon vector
data of character fonts stored in the character font disc 11 and the
character font codes in the image describing program P.sub.i.
The character vector data V.sub.l, the diagram vector data V.sub.f and the
multi-tone image data D.sub.i are transmitted from the host processor 10
to the data management unit 21 in the image integrating device 200. The
data management unit 21 divides an image plane into a plurality of areas
based upon these data.
FIG. 2 conceptionally shows images on the image plane IP, which images are
expressed by the image description program P.sub.i and the multi-tone
image data D.sub.i. In the image plane IP, there are five regions A.sub.1
through A.sub.5 in which characters, diagrams or patterns are arranged. In
all of them, the regions A.sub.1 and A.sub.3 contain characters only,
while the regions A.sub.2 and A.sub.5 contain photographs of pictures
only. The region A.sub.4 contains diagrams only. In FIG. 2, squares
(A.sub.1, A.sub.3) show regions of characters, elipses (A.sub.2, A.sub.5)
show regions of pictures, and a parallelogram (A.sub.4) shows a region of
a diagram or a line drawing. On the other hand, the image plane IP is
divided into equal rectangular strip regions R.sub.1 through R.sub.11. As
described later, each strip region has a predetermined dimensions and the
image processing unit 220 executes an image processing to each of the
strip regions R.sub.1 through R.sub.11.
Ordinarily, characters and diagrams (line drawings) can be expressed by
binary data, and they are expressed at a high resolution (e.g., 1500 dpi)
to reproduce their shapes clearly. On the other hand, patterns are
expressed by multivalued data (8 bit data in this preferred embodiment),
and they are generally expressed with low resolution (e.g., 300 dpi).
Then, the data management unit 21 judges which mode in the following three
modes images in each strip region should be processed in.
(I) Mode 1: A mode for procesing a binary high resolution image data of an
image including characters and/or diagrams (line drawings) only. In this
Mode 1, the size of each pixel is 1500 dpi (dots per inch) and the image
data for each pixel is represented by 1 bit. The image frame memory 25a,
25b or 25c is used for storing image data for 64M (mega) pixels.
(II) Mode 2: A mode for processing a multivalued low resolution image data
of an image including patterns only. The size of each pixel is 300 dpi and
the image data for each pixel is represented by 8 bit. The image frame
memory 25a, 25b or 25c is used for storing image data for 8M pixels.
(III) Mode 3: A mode for processing a multivalued high resolution image
data of an image including characters and/or diagrams as well as patterns.
The size of each pixel is 1500 dpi and the image data for each pixel is
represented by 8 bit. The image frame memory 25a, 25b or 25c is used for
storing image data for 8M pixels.
The procedures for processing images in a selected one of these modes are
previously stored in the data management unit 21 in the form of software
programs.
In general, when the symbols P.sub.j, N.sub.j and S.sub.j (j=1,2,3) are
introduced in accordance with the following definition (i) through (iii),
these values P.sub.j, N.sub.j and S.sub.j are so selected that the
following expressions (1) through (4) are held.
(i) P.sub.j : the number of pixels stored in the image frame memory:
(ii) N.sub.j : the data length or the number of bits in representing each
pixel;
(iii) S.sub.j : resolution in dpi.
P.sub.j .times.N.sub.j .ltoreq.M.sub.t (j=1,2,3) (1)
P.sub.1 >P.sub.2 =P.sub.3 (2)
N.sub.1 <N.sub.2 =N.sub.3 (3)
S.sub.1 =S.sub.3 S.sub.2 (4)
Preferably, the values P.sub.j, N.sub.j and S.sub.j (j=1,2,3) are so
selected that the following expressions (5) is held in place of the
expression (1).
P.sub.j .times.N.sub.j =A.sub.t (i=1,2,3) (5)
In the preferred embodiment, values N.sub.c, N.sub.d, N.sub.p, S.sub.c,
S.sub.d and S.sub.p are defined in the expressions (6) through (11) and
the values P.sub.j, N.sub.j and S.sub.j (j=1,2,3) are determined in the
following expressions (12) through (20), as understood from the
above-indicated definition (I), (II) and (III) of the Modes 1-3.
##EQU1##
Although images of characters and diagrams are represented in the form of
binary monochrome images in many cases, they may be represented in the
form of multi-tone images in which one or more arbitrary colors are
designated. Such a multivalued image is processed in the Mode 3 even if it
is an image including characters and/or diagrams only.
FIGS. 3(a) through 3(c) are diagrams showing a concept of the image data
for each pixel in the Modes 1 through 3, respectively. The heights of
rectangular poles in FIGS. 3(a) through 3(c) show the numbers of bits in
the image data for each pixel, while widths of their bottoms and tops show
dimensions of a single pixel. Since the size of a single pixel is 1500 dpi
in the Modes 1 and 3, the width of the bottom of each rectangular pole is
about 17 .mu.m. On the other hand, since a single pixel is 300 dpi in the
Mode 2, the width of the bottom of the pole is about 85 .mu.m.
FIGS. 4(a) through 4(c) are diagrams relatively showing the dimensions of
image areas which can be stored in each image frame memory 25a, 25b, 25c
of 8M bite under respective modes. In the Mode 1, each frame memory 25a,
25b, 25c can store image data of an image region R.sub.m1 including 64M
(=65536) pixels of 1500 dpi. In the Mode 2, each frame memory 25a, 25b,
25c can store image data of an image region R.sub.m2 including 8M (=8192)
pixels of 300 dpi. The image region R.sub.m2 has an area equal to that of
a region including 200M pixels of 1500 dpi. In the Mode 3, each frame
memory 25a, 25b, 25c can store image data of an image region R.sub.m3
including 8M pixels of 1500 dpi. The area rate of the three image regions
R.sub.m1 through R.sub.m3 is 8:25:1. In other words, the image region
R.sub.m3 which can be stored in each frame memory 25a, 25b, 25c in Mode 3
is dimensionally smallest of the image regions R.sub.m1 through R.sub.m3
which may be stored in any of the modes 1 through 3. The image R.sub.m3 is
1/8 of the image region R.sub.m1 in the Mode 1 and 1/25 of the image
region R.sub.m2 in the Mode 2. Areas of the strip regions R.sub.1 through
R.sub.11 shown in FIG. 2 are set equal to an area of the image region
R.sub.m3 in FIGS. 4(a) through 4(c). In this way, when a strip region
including pictures as well as character and/or diagrams is processed in
the Mode 3, the image data of the strip region can be stored in one of the
image frame memories 25a-25c. Eight of strip regions including characters
and/or diagrams but no pictures can be stored in one of the image frame
memories 25a-25c at a time. Furthermore, twenty-five of strip regions
including pictures only can be stored in one of the image frame memories
25a-25c at a time.
The data management unit 21 determines a processing mode among the Modes 1
through 3 so that an integrated image is generated in the image frame
memory in accordance with the highest resolution and the largest number of
bits in the image data of images contained in the strip regions R.sub.1
through R.sub.11. The image data for the strip regions R.sub.1 through
R.sub.3, R.sub.7 and R.sub.8 are processed in the Mode 1. The strip
regions R.sub.4 and R.sub.11 are processed in the Mode 2, while the strip
regions R.sub.5, R.sub.6, R.sub.9 and R.sub.10 are processed in the Mode
3.
The image frame memories 25a-25c are prepared so that arbitrary one of
various integrated images can be written in a corresponding image frame
memory.
After the determination of the mode of each strip region in the data
management unit 21 is completed, the image processing unit 220 generates
respective parts of an integrated image in the strip regions R.sub.1
through R.sub.11 based upon the character vector data V.sub.l, the diagram
vector data V.sub.f and the multi-tone image data D.sub.i in accordance
with instructions of the data management unit 21 in the following manner
and stores the same in the image frame memories 25a through 25c.
The character vector data V.sub.l in the strip region R.sub.1 is supplied
from the data management unit 21 to the image processing unit 220. The
character vector data V.sub.l is processed in the data processing unit 22a
of the image processing module 220a. The data processing units 22a through
22c are so-called second generation graphic controller LSIs, which perform
a coordinate transformation processing, such as an enlargement, reduction,
rotation and the like, to the vector data V.sub.l and V.sub.f and the
multi-tone image data D.sub.i and has a function to transform the vector
data V.sub.l and V.sub.f into raster data R.sub.l and R.sub.f.
Furthermore, the part of the integrated image on the strip region R.sub.1
is generated on the basis of the raster data R.sub.l and R.sub.f as well
as the multi-tone image data D.sub.ia, after the transformation. This
portion of the integrated image is stored, or drawn, in the image frame
memory 25a. Since the strip region R.sub.1 contains characters only, the
image drawing is done based simply upon the character raster data R.sub.l.
Since the strip region R.sub.1 is processed in accordance with the Mode 1,
the image frame memory 25a is used as a frame memory of 64M pixels.times.1
bit, where each one pixel corresponds to 1500 dpi. The strip regions
R.sub.2 and R.sub.3 as well as the strip region R.sub.1 are processed in
accordance with the Mode 1. As previously mentioned, image data on eight
of the strip regions obtained through the processing of Mode 1 can be
stored in one image frame memory at a time. Therefore, the image data in
the strip regions R.sub.1 through R.sub.3 can be stored in the image frame
memory 25a at a time.
The strip region R.sub.4 is processed in the Mode 2 because it includes
pictures only. The Mode 2 for the strip region R.sub.4 is different from
the Mode 1 for the strip regions R.sub.1 through R.sub.3, and therefore,
as shown in FIG. 2, an image data in the strip R.sub.4 is stored in the
next image frame memory 25b. At this time, the multi-tone image data
D.sub.ia in the strip region R.sub.4 is applied to the data processing
unit 22b of the image processing module 220b for coordinate transformation
and thereafter is stored in the image frame memory 25b. Thus, when a
processing mode for strip regions is changed, an image processing module
for storing the image part obtained is also changed, whereby images of
different modes cannot exist in any one of image frame memories 25a-25c.
The strip region R.sub.5 includes characters and pictures. The data
management unit 21 detects that the rectangle region R.sub.5 includes
characters and pictures and decides to process the data thereof in the
Mode 3. This processing mode (Mode 3) is different from the processing
mode (Mode 2) for the prior strip region R.sub.4, and hence, the character
vector data V.sub.l and the multi-tone image data D.sub.i in the strip
region R.sub.5 are processed by the third data processing module 220c. The
data processing unit 22c in the data processing module 220c processes the
character vector data V.sub.l and the multi-tone image data D.sub.i in the
strip region R.sub.5 and draws the part of the integrated image in the
image frame memory 25c. Since the processing of the strip region R.sub.5
is carried out in accordance with the Mode 3, the image memory 25a is used
as a frame memory of 8M pixels.times.8 bit, in which each pixel
corresponds to 1500 dpi. As to a part of the strip region R.sub.5 where a
character and a picture overlap each other, it is designated in the image
description program under instructions of an operator which image priority
should be given to (i.e., which image should be visible). The data
processing unit 22c integrates respective images of the character and the
picture in the strip region R.sub.5 and stores an image data of the
integrated image in the image frame memory 25c. On the integration, a data
in a part where a character (or a diagram) in the character image (or a
diagram image) should be solid or filled is provided with the maximum
value "255" within values that can be expressed with 8 bit, while a data
in a part where it should keep blank is provided with the minimum value
"0".
The strip region R.sub.6, similar to the strip region R.sub.5, is processed
in the Mode 3. However, since the image frame memory 25c is full of image
data of the strip region R.sub.5, the data processing unit 22a in turn
performs a processing for the region R.sub.6. That is, the data processing
unit 22a integrates images of characters and patterns, and an image data
of the integrated image thus obtained is stored in the image frame memory
25a.
When or before the image data in the region R.sub.6 is stored in the image
frame memory 25a, the image data in the strip regions R.sub.1 through
R.sub.3 is read from the image frame memory 25a and converted into
halftone dots in the dot generator 23. In other words, the image
processing modules 220a through 220c including the image frame memories
25a through 25c, respectively are cyclically employed for generating
respective parts of the integrated image in the strip regions R.sub.1
through R.sub.11 on the image plane IP. Shift from one image frame memory
to another image frame memory for storing a part of the integrated image
newly generated is carried out every time when the one image frame memory
is full of image data as shown in the above and every time when the mode
in the generation of the integrated image is changed from one strip region
to the next strip region.
The image data for the other strip regions R.sub.7 through R.sub.11 are
generated similar to the above. That is, the image data for the strip
regions R.sub.7 and R.sub.8 are processed in the Mode 1 and stored in the
image frame memory 25b. The strip regions R.sub.9 and R.sub.10 are
processed in the Mode 3 while the strip region R.sub.11 is processed in
the Mode 2, and their respective image data are stored in the image frame
memories 25c, 25a and 25b, respectively.
The image data D.sub.p of each pixel in each strip region is temporarily
stored in corresponding one of the image frame memories 25a through 25c
and is transmitted to the dot generator or halftone dot generating unit
23. At this time, the image data D.sub.p stored in the image frame
memories 25a through 25c are those for the image plane including areas
where no character, no diagram and no pattern is provided, i.e., areas
other than regions A.sub.1 through A.sub.5 shown in FIG. 2. The image data
D.sub.p is serially read out from the head coordinate Ymin to the end
coordinate Ymax on each scanning line along a main scanning direction Y,
while selection of scanning lines is serially conducted in respective
strip regions along a subscanning direction Y.
The dot generator 23 compares the image data with threshold values to
generate a halftone dot image data (binarized image data) D.sub.h
expressing a binary brigh | | |
