Image analysis – Image enhancement or restoration – Image filter
Reexamination Certificate
1999-05-25
2003-06-10
Lee, Thomas D. (Department: 2724)
Image analysis
Image enhancement or restoration
Image filter
C382S266000, C382S209000, C382S218000
Reexamination Certificate
active
06577774
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an image forming apparatus and image forming method used in various types of devices such as a printer having a multi-value engine, facsimile equipment, an optical filing device, or an electronic sorting device, and more specifically to an image forming apparatus for selectively executing smoothing for inputted image data.
BACKGROUND OF THE INVENTION
Conventionally some types of image forming apparatus such as a digital copier having multiple functions such as a facsimile or a printer have a multi-value engine section and a frame memory capable of storing multi-value data therein and output any of 1-bit/dot, 2-bit/dot or 8-bit/dot image according to the option.
FIG. 3
is a block diagram showing configuration of an image processing section based on the conventional technology for executing smoothing by converting binary image data to multi-valued image data. In this figure, a line buffer
301
is a memory for storing therein inputted binary image data for a plurality of lines and transfers a group of n(dot)×m(line) data around a remarked pixel to a template matching section
302
.
The template matching section
302
compares the data group to a preset data group and transfers a result of comparison to a smoothing section
303
. The smoothing section
303
converts a remarked pixel to a j(dot)×k(line) enlarged image for smoothing according to a result of comparison in the template matching section
302
, while a dividing/smoothing section
304
executes the processing for dividing and smoothing the image according to an expansion ratio of the image and outputs the image data having been subjected to the processing for smoothing by converting binary image data to multi-valued image data.
In the image processing apparatus described above, to accommodate multi-valued image data, there has been known the apparatus in which a line buffer
401
for storing therein multi-valued data for a plurality of lines and a multi-valued template matching section
402
are provided, and smoothing processing for multi-valued image data is executed in the smoothing section
403
with the processing for dividing and smoothing executed in the dividing/smoothing section
404
as shown, for instance, in FIG.
4
.
However, there occurs the problem that a larger memory capacity for an increased bit number for multi-valued image data is required for the line buffer section
401
as well as for the template matching
402
. To solve this problem, a multi-value smoothing section
500
for multi-valued image data as shown in
FIG. 5
is provided.
Even in a case of multi-valued image data for a remarkably jagged image, a density may be full (100%) in some sections, and to respond to this problem, a determining block
501
for determining whether density of an inputted multi-valued image is full or not is provided on the upstream side of a line buffer
502
. It should be noted that a template matching section
503
, a smoothing section
504
, and a dividing/smoothing section
505
are provided, as described above, on the downstream side of the line buffer
502
and further a selector
506
is provided for switching the pixels to be converted according to a result of processing in the template matching section
503
.
The determining block
501
supplies, for instance, only image data for pixels having a full density value of the image as shown in
FIG. 6A
as true value (1) to the line buffer
502
, subjects the pixels to smoothing processing by converting binary data to multi-values in the template matching section
503
, smoothing section
504
, and dividing/smoothing section
505
, and switching only the converted pixels with the selector
506
.
Japanese Patent Laid-Open Publication No. HEI 9-130628 discloses as a technology related to the multi-value smoothing processing for the multi-valued image data for a color image as described above.
In the apparatus for processing multi-valued data based on the conventional technology as shown in
FIG. 5
, however, there are jagged images for characters and strings, so that it is not appropriate to execute smoothing processing only to 1-bit/dot binary image data. Therefore, it is required to execute smoothing processing to multi-value data. However, if input image data is subjected as it is to the smoothing processing there is a disadvantage that a larger memory capacity is required.
When a color image based on multi-valued image data is outputted, an image with a photograph (image section) and characters (character section) coexisting therein is required to be frequently outputted. Although the smoothing processing is effective for reducing jags in the characters, when the same smoothing processing is executed to the whole image to be outputted, if a data array identical to the template data is present also in any image section, the gradation becomes lower as the same processing is executed to both the character sections and image sections, which may sometimes generate a false contour not present in the original data thereof. Further, it is required in some types of data to execute smoothing processing only to black characters or to change the degree of the smoothing processing according to colors, but the conventional technology can not be applied to the cases as described above.
SUMMARY OF THE INVENTION
It is a first object of the present invention to reduce a data volume in template matching for the purpose to reduce a required memory capacity by converting multi-valued input image data to binary image data in a smoothing process.
It is a second object of the present invention to realize an optimal smoothing process by determining whether smoothing is to be executed or not according to the type of image data.
In the image forming apparatus according to the present invention, input image data is compared with a threshold value data previously set and is then converted to binary data, so that the amount of image data for a n×m area for comparison during template matching can be reduced.
Other objects and features of this invention will become apparent from the following description with reference to the accompanying drawings.
REFERENCES:
patent: 5249242 (1993-09-01), Hanson et al.
patent: 5383036 (1995-01-01), Mailloux et al.
patent: 6278804 (2001-08-01), Okuyama
patent: 9-130628 (1997-05-01), None
Lee Thomas D.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Ricoh & Company, Ltd.
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