Image analysis – Pattern recognition – Feature extraction
Reexamination Certificate
1998-09-14
2003-02-11
Mehta, Bhavesh (Department: 2721)
Image analysis
Pattern recognition
Feature extraction
C358S001170, C358S003280, C382S135000, C382S137000, C382S165000
Reexamination Certificate
active
06519364
ABSTRACT:
TECHNICAL FIELD
The present invention relates generally to a method and an apparatus for recognizing images, and a copying machine and a printer using the same.
BACKGROUND ART
In a reading portion in a general digital color copying machine (laser type), as shown in
FIG. 1
, an image sensor
1
formed by a line of CCDs having a reading width identical to the width of an original
2
is used and provided opposing the original. In this example, the width d of image sensor
1
in practice is smaller than the width D of the original, since a reducing optics including a lens
3
is used, but in some other cases, the same width is employed. If the lengthwise direction of image sensor
1
is set as a main scanning direction, image sensor
1
may be moved back and forth in a sub scanning direction orthogonal to the main scanning direction.
In reading an original using such image sensor
1
, the entire raster scan method is employed. More specifically, as shown in
FIG. 2
, image sensor
1
is positioned at the top of original
2
, and the first line a (in the main scanning direction) is read by image sensor
1
. Then, image sensor
1
is moved by
1
line in the sub scanning direction, and the next line b (in the main scanning direction) is read. Thereafter, the process is sequentially repeated to read the entire original, based on which a prescribed image processing is performed for printing.
The copying machine employing the kind of entire raster scanning method as described above is capable of copying data in very high precision, and therefore a printed, out copy could be almost identical to the original. The machine could be therefore used to counterfeit anything prohibited to copy such as paper currencies.
Hence, in order to prevent such misconduct, an image recognizing apparatus to recognize particular kinds of originals is installed and image data read by image sensor
1
is subjected to a recognizing process, so that the presence/absence of a particular pattern printed on any items, i.e., a pattern prohibited to copy, is determined. If the particular pattern is detected, output is stopped, or a prescribed prohibiting process such as painting out is performed.
Meanwhile, there are other color copying machines than the digital color-copying machine such as ink jet type machine. The method of reading images by this type of copying machine is as shown in
FIGS. 3A and 3B
. More specifically, an image sensor
5
of a small width is provided opposite to original
2
. Image sensor
5
is capable of reading 128 dots at 400 dpi. There are further provided an X motor for moving image sensor
1
in the X-direction and a Y motor for movement in the Y-direction, and revolution of each of the motors is controlled to move image sensor
5
to an arbitrary position in a two-dimensional plane of original
2
.
In reading image data, the X motor is normally rotated to move image sensor
5
in the X-direction, from position X
0
to position of Xn. During the movement, image data at an opposing portion (a reading region a in the first line) is read. Then, the X motor is reversely rotated, and the Y motor is rotated by a prescribed angle in the normal direction to move image sensor
5
obliquely as shown in broken line in the figure, and positioned at the head (X
0
) of reading region b in the second line. Then, the Y motor is stopped, and the X motor is normally rotated to move image sensor
5
from position X
0
to position Xn in reading region b in the second line. During the movement, image data in the opposite portion (region b) is read.
Thereafter, by repeating the above process, the entire original is read. Reading of images on the basis of each region a, b . . . is by raster scanning in a stripped shaped region as shown in FIG.
4
. (The solid line arrows in the figure denote periods of reading images, and the line connecting the adjacent arrows represents the image sensor in the process of moving, and data of each pixel is read following the arrows.)
In printing out, each time one region is read, an image corresponding to the region is formed by a prescribed image processing, and the thus formed image for the one region is output. More specifically, as shown in
FIG. 5
, reading data for one region (region a in the first line in the shown example) is applied from the reading portion including image sensor
5
to image processing portion
6
, where a prescribed image processing is performed, data for one region is applied to the output portion, and data corresponding to a region a′ for the read region a is printed using a printing head
7
(equal size printing). Thus, image reading and image formation are linked to print data bit by bit, so that an inexpensive, small memory copying machine may be implemented.
Furthermore, printing head
7
provided at the output portion has 128 nozzles for one color component corresponding to the reading portion, and the on/off of the color component for the corresponding nozzles is controlled based on the color of each pixel detected by the detection element of a corresponding sensor.
The above ink jet type color copying machine is not provided with an image recognizing apparatus such as those installed in a conventional laser type digital color copying machine for recognizing special kinds of originals.
However, in recent years, the above-described ink jet type color printer came to be capable of highly precise color printing, and therefore the sameness between an original and a copy thereof is increased. Thus, there is a need for an image recognizing apparatus for recognizing particular kinds of originals. As described, however, the image recognizing apparatus that has been used in the entire raster scanning digital color copying machine cannot be applied as is, because of the difference in the scanning method.
Furthermore, since the operation of the reading portion in the process of expansion/reduction is different between these copying machines, the above-described problem is more notable. More specifically, in the digital color-copying machine, as shown in
FIGS. 1 and 2
, image sensor
1
moves only in a single direction. As a result, the resolution in reading an original in the width-wise direction (in the arranging direction of image sensor
1
/the main scanning direction) is constant regardless of the expansion/reduction ratio. The resolution in reading in the sub scanning direction is changed by expansion/reduction. More specifically, the moving speed of image sensor
1
in the sub scanning direction is lowered in the expansion process, and raised in the reduction process, and the speed is adjusted by the expansion/reduction ratio. Such simple movement allows image data with the same resolution to be available regardless of the magnification simply by thinning and supplementing image data read in the sub scanning direction as necessary.
In contrast, in the ink jet type machine, 128 nozzles provided at printing head
7
are controlled at a time for output, during reading a strip-shaped region, data from the head to N-th data is used, while N+1-th data and on is not used, and the Y motor is rotated to move image sensor
1
for a distance corresponding to the N pieces of data in the image sensor, in order to read the next strip-shaped region (the specific process of which will be described later).
Therefore, part of an output signal from image sensor
1
is invalidated, the moving distance in the Y-direction is not constant, unlike the reading mechanism of the conventional digital color copying machine, and the conventional recognizing apparatus as is cannot be applied.
Furthermore, in the sub scanning direction, the moving speed of the image sensor is changed depending upon the magnification, as is the case with the laser type apparatus. Accordingly, read data is two-dimensionally changed depending upon the magnification, and the same image data is not available depending upon the magnification, simply by thinning or supplementing the read data in the order of application.
The present invention is in view of the above-described backgroun
Desire Gregory
Dickstein , Shapiro, Morin & Oshinsky, LLP
Mehta Bhavesh
Omron Corporation
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