Image analysis – Image transformation or preprocessing – Changing the image coordinates
Reexamination Certificate
1996-03-20
2001-09-11
Bella, Matthew C. (Department: 2621)
Image analysis
Image transformation or preprocessing
Changing the image coordinates
C382S197000, C382S199000, C358S448000, C358S451000
Reexamination Certificate
active
06289136
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an image processing apparatus and method and, more particularly, to an image processing apparatus and method for magnifying a digital multivalued image.
2. Description of the Related Art
An apparatus of this type associated with digital binary images has already been disclosed in Japanese Patent Laid-Open No. 5-174140.
In this proposal, when a binary image is to be subjected to magnifying processing, the contour information of the character/line drawing components of the binary image is extracted, and a magnified image is generated on the basis of the extracted contour information instead of magnifying the binary image itself. It is an object of the proposal to obtain a binary image with high quality.
More specifically, in Japanese Patent Laid-Open No. 5-174140, outline vectors are extracted from a binary image, and smoothing processing is performed with respect to the extracted outline vector data. The smoothed outline vector data is magnified at a desired (arbitrary) magnification. Contours are then drawn and the areas defined by the contours are painted to reproduce a binary image. With this operation, a high-quality digital binary image magnified at the desired magnification (arbitrary) is obtained.
The main part of this proposal will be briefly described below.
FIG. 56
is a block diagram best representing the characteristic features disclosed in Japanese Patent Laid-Open No. 5-174140. Referring to
FIG. 56
, a binary image acquisition unit
101
acquires a digital binary image to be subjected to magnifying processing, and outputs a raster scanning type binary image. An outline extraction unit
102
extracts coarse contour vectors (outline vectors before smoothing/magnifying processing) from the raster scanning type binary image. An outline smoothing/magnifying unit
103
performs smoothing/magnifying processing for the coarse contour vector data in the form of vector data. A binary image reproduction unit
104
reproduces raster scanning type binary image data from the outline vector data. A binary image output unit
105
is a printer or display device for displaying the raster scanning type binary image data, producing a hard copy, or outputting the data to a communication line or the like.
For example, the binary image acquisition unit
101
is constituted by a known binary image input device for reading an original image as a binary image and outputting the read image as binary data in the raster scanning form.
For example, the outline extraction unit
102
is constituted by a device disclosed in Japanese Patent Laid-Open No. 4-157578 previously proposed by the assignee of the present application.
FIG. 57
shows a scanning form for raster scanning type binary image data output from the binary image acquisition unit
101
, and also a scanning form for raster scanning type binary image data received by the outline extraction unit
102
. In this form, the outline extraction unit
102
receives raster scanning type binary image data output from the binary image acquisition unit
101
. Referring to
FIG. 57
, a pixel
111
is a given pixel of a binary image during a raster scanning operation, and an area
112
is a 9-pixel area including eight pixels adjacent to the pixel
111
. The above outline extraction unit disclosed in Japanese Patent Laid-Open No. 4-157578 switches target pixels in the raster scanning order, and detects a contour side vector (horizontal or vertical vector) between each target pixel and each adjacent pixel in accordance with the state of each pixel (white or black pixel) in a 9-pixel area like the area
112
. If a contour side vector is present, the outline extraction unit extracts the start coordinates and direction data of the side vector, and sequentially extracts coarse contour vectors while updating the relationship in connection between these side vectors.
FIG. 58
shows a state wherein contour side vectors between a target pixel and pixels adjacent to the target pixel are extracted. Referring to
FIG. 58
, a mark “&Dgr;” represents the start point of a vertical vector (or the end point of a horizontal vector), and a mark “O” represents the start point of a horizontal vector (or the end point of a vertical vector).
FIG. 59
shows coarse contour vector loops extracted by the outline extraction unit described above. In this case, each square defined by the matrix indicates the pixel position of an input image; each blank square, a white pixel; and each hatched mark “&Circlesolid;”, a black pixel. Similar to
FIG. 58
, each mark “&Dgr;” represents the start point of a vertical vector; and each mark “O”, the start point of a horizontal vector.
As is apparent from the case shown in
FIG. 59
, the outline extraction unit
102
extracts areas where pixels are coupled to each other as coarse contour vector loops including horizontal and vertical vectors which always appear alternately and continuously, although the horizontal and vertical vectors differ in length. Note that in this case, extraction processing is performed such that a black pixel area is located on the right side with respect to the direction of the extraction processing. In addition, the start point coordinates of the coarse contour vectors are extracted as the middle positions between the respective pixels of the input image. That is, when the position of each pixel is expressed by integers (x,y), the start point of an extracted vector is expressed by values obtained by adding or subtracting 0.5 to or from the respective coordinate values. More specifically, one pixel in an original image is determined as a pixel (rectangle) having a significant area and extracted as a coarse contour loop.
The coarse contour vector group extracted in this manner is output from the outline extraction unit
102
in
FIG. 56
according to a data format like the one shown in FIG.
60
. That is, the coarse contour vector group is constituted by a total number n of coarse contour loops extracted from an image, and a group of coarse contour loop data of the first contour loop to the ath contour loop. Each coarse contour loop data is constituted by the total number of the start points of contour side vectors (equivalent to the total number of contour side vectors) present in the coarse contour loop, and a string of the values (the start points of horizontal and vertical vectors are alternately arranged) of the start point coordinates (x- and y-coordinate values) of the respective contour side vectors in the order of constituting the loop.
The outline smoothing/magnifying unit
103
shown in
FIG. 56
receives the coarse contour vector data (see
FIG. 60
) output from the outline extraction unit
102
. The unit
103
then performs smoothing processing and magnifies the data at a desired magnification in the form of outline vector data (coordinate values).
FIG. 61
shows the arrangement of the outline smoothing/magnifying unit
103
in more detail. Referring to
FIG. 61
, a first smoothing/magnifying unit
152
smoothes and magnifies input coarse contour data at a magnification set by a magnification setting unit
151
. A second smoothing unit
153
further performs smoothing of the processing result to obtain a final output. The magnification setting unit
151
may supply a value set by a DIP switch, a dial switch, or the like in advance to the first smoothing/magnifying unit
152
, or may supply a value externally provided via an I/F (interface) to the first smoothing/magnifying unit
152
. The magnification setting unit
151
is a unit for providing information designating specific magnifications respectively in the main scanning (horizontal) direction and the subscanning (vertical) direction with respect to an image size supplied as input data.
The first smoothing/magnifying unit
152
receives magnification information from the magnification setting unit
151
and performs smoothing/magnifying processing.
FIG. 62
shows a hardware arrangement for realizing outline smoothing/magnifying processing. Referring to
FIG. 62
Ishida Yoshihiro
Koga Shinichiro
Morimoto Osamu
Oshino Takahiro
Bella Matthew C.
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
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