Image analysis – Image transformation or preprocessing – Changing the image coordinates
Reexamination Certificate
1997-12-15
2001-09-11
Grant, II, Jerome (Department: 2724)
Image analysis
Image transformation or preprocessing
Changing the image coordinates
C382S298000, C358S451000
Reexamination Certificate
active
06289137
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to an image processing apparatus and method for processing image data and, more particularly, to an image processing apparatus and method for obtaining an image of a good picture quality.
2. Related Background Art
Hitherto, according to the standard of a G3 facsimile apparatus, a scanning line density for reading or recording is predetermined to 8 dots/mm for the main scanning direction and to 3.85 lines/mm (standard), 7.7 lines/mm (fine), and 15.4 lines/mm (super fine) for the sub scanning direction.
In almost of the conventional facsimile apparatuses, therefore, both of the reading means and the recording means use a system corresponding to the above scanning line densities. Particularly, with respect to the recording means, in many cases, a thermal recording system is used from viewpoints of easiness of the control and a reduction of a space.
However, in case of the thermal recording paper, since it cannot be preserved because of discoloration and the after-writing (namely, characters or the like are written to the paper after the recording) cannot be performed, a facsimile apparatus using a normal paper as a recording paper is rapidly widespread.
As a normal paper recording system in this case, an LBP (laser beam printer) system or an ink jet system is generally used. However, in such LBP or ink jet recording apparatus, ordinarily, a resolution is set to about 400 dpi and is very higher than a scanning line density of the G3 standard. In case of performing the G3 reception and recording or in case of copying and recording a read original, therefore, a resolution of image data has to be converted in accordance with a resolution of the recording apparatus and, after that, the image data is recorded. A specific example of such a case will now be described hereinbelow.
FIG. 20
shows a block diagram of a conventional normal paper recording facsimile apparatus.
In
FIG. 20
, reference numeral
2001
denotes a contact sensor unit (CS) to read an original image. In the conventional apparatus, the original image is read at a resolution of 8 dots/mm in the main scanning direction and, for example, 7.7 lines/mm in the sub scanning direction.
Reference numeral
2002
denotes an analog image processing unit for executing analog image processes such as DC reproduction, shading correction, and the like to an analog output of the CS
2001
; and
2003
indicates an A/D conversion unit for converting an output of the analog image processing unit
2002
to digital data of multivalues every pixel.
Reference numeral
2004
denotes a luminance/density conversion table unit for LOG converting luminance data of each pixel as an output of the A/D conversion unit
2003
to density data; and
2005
indicates an error diffusion processing unit for executing a half-tone process to multivalue output data of the luminance/density conversion table unit
2004
by an error diffusing method, thereby producing binarized image data.
In the above error diffusing process, a binarizing process of a target pixel is executed by using an error diffusion matrix shown in FIG.
21
. As is well known hitherto, according to the error diffusing process, the multivalue pixel data which was inputted is binarized by a predetermined threshold value and errors between the pixel data and the threshold value are two-dimensionally diffused in accordance with weight coefficients of an error diffusion matrix. Thus, a density as a whole image can be preserved and a half-tone image can be falsely obtained. By two-dimensionally diffusing the errors, a smooth half-tone image which is visually beautiful can be obtained.
Reference numeral
2006
denotes a data control unit to control a transfer of image data in accordance with each of the transmission mode, reception mode, and copy mode;
2007
a resolution conversion unit to convert a resolution of the image data to a resolution of a printer when the image data is printed and recorded;
2008
a density correction unit to perform a density correction to the image data which was resolution converted by the resolution conversion unit
2007
; and
2009
an ink jet printer to print and record. In the conventional apparatus, a printer of a resolution of (360 dpi×360 dpi) is used.
Reference numeral
2010
denotes a modem to modulate and demodulate the image data upon transmission or reception;
2011
an NCU to control an office line upon transmission or reception; and
2012
a CPU to control each of the above units.
The operation of the conventional apparatus will now be described hereinbelow.
In the transmission mode, a transmission original is read by the CS
2001
at a resolution of 8 dots/mm in the main scanning direction and, for example, 7.7 lines/mm in the sub scanning direction by the selection of the operator. A read output of the original is corrected by the analog image processing unit
2002
and is converted to multivalue digital data every pixel by the A/D conversion unit
2003
.
The digital data is LOG converted to the density data by the luminance/density conversion table unit
2004
and is binarized by the error diffusion processing unit
2005
, so that the binary image data is outputted. In the conventional apparatus, the image data which is obtained here has a resolution of 8 dots/mm in the main scanning direction and 7.7 lines/mm in the sub scanning direction.
The image data is sent to the modem
2010
by the data control unit
2006
and is modulated to the analog transmission signal and is transmitted to an office line through the NCU
2011
.
In the reception mode, the analog transmission signal which arrives from the office line is sent to the modem
2010
through the NCU
2011
and is demodulated to the digital image data. However, a resolution in this instance is set to 8 dots/mm in the main scanning direction based on the G3 standard. It is now assumed that the data of a resolution of, for example, 7.7 lines/mm in the sub scanning direction was received.
The data control unit
2006
transfers the image data to the resolution conversion unit
2007
and its resolution is converted.
Namely, to record the data of (8 dots/mm×7.7 lines/mm) by the ink jet printer
2009
of (360 dpi×360 dpi), pixels are added in accordance with a predetermined pattern of the image data so as to increase the number of pixels in the main scanning direction by about 1.77 times and in the sub scanning direction by about 1.84 times.
In the ink jet system, in case of seeing the whole image, the recording image becomes too dense than the actual original image because of a cause such as a blur of the ink or the like.
Therefore, the density correction unit
2008
executes a density correction by replacing the black pixels to the white pixels in accordance with the pattern of the image data in order to avoid a phenomenon such that the image density when the image is printed by the ink jet printer
2009
seems to be dense due to an increase in number of pixels by the resolution conversion mentioned above.
The data is sent to the ink jet printer
2009
and is recorded as an image at a resolution of (360 dpi×360 dpi).
In the copy mode, the original image read by the CS
2001
is processed in a manner similar to the case in the transmission mode and is obtained from the error diffusion processing unit
2005
at a resolution of, for example, (8 dots/mm×7.7 lines/mm) as binarized image data.
The image data is transferred to the resolution conversion unit
2007
by the data control unit
2006
.
The image data is, further, resolution converted from a resolution of (8 dots/mm×7.7 lines/mm) to a resolution of (360 dpi×360 dpi) by the resolution conversion unit
2007
in a manner similar to the reception mode. In a manner similar to the case of the recording of the reception data mentioned above, in order to avoid that the image becomes too dense as a whole, the density correction unit
2008
inverts the image data from the black pixels to the white pixels and, after that, the data is recorded as
Kurahayashi Sadasuke
Sakamoto Masahiro
Sugiyama Norio
Ushida Katsutoshi
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Grant II Jerome
LandOfFree
Image processing apparatus and method does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Image processing apparatus and method, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Image processing apparatus and method will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2488584