Image analysis – Pattern recognition – Feature extraction
Reexamination Certificate
1998-10-06
2001-01-23
Tran, Phuoc (Department: 2721)
Image analysis
Pattern recognition
Feature extraction
C382S242000, C382S243000, C382S266000, C382S268000, C382S269000
Reexamination Certificate
active
06178264
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to image cutout methods and apparatus, and more specifically to an image cutout method and apparatus for converting an image into data form for digital processing to cut out an image of a desired subject therefrom.
2. Related Art Statement
In recent years, the technology of digital image processing for converting an image into data form for digital processing has been widely used. Also in a field of a photomechanical process for making a printing plate including images, by introducing the technology of digital image processing, most works which had previously been done depending on workers' experiences and intuition were automated, and as a result it became possible to efficiently make a high quality plate even by workers without high skills.
“Cutout” is one of the processes in the photomechanical process. This is a process for cutting out a subject part from an original photographic image with a background. For example, this process is performed when a plate for a catalog or an advertising leaf let is made containing a photograph of a product. If this is done by hand, much expense in time and effort is required. Therefore, a method has been devised that the original photograph is read by a scanner to be converted in data form and the obtained image data is subjected to digital processing to be cut out.
The method is as follows, for example. That is, the image data is binarized with an appropriate reference color (for example, Y, M, C, K) and (positional information of) a boundary line where the obtained bit map is on/off is obtained. Then, only data inside the obtained boundary line is extracted. Thus, the image of the subject part can be cut out from the original image without tracing by an operator.
However, in the above method, it is possible to accurately cut out the image of the subject part when the subject (and the background) has a single-color or a color close thereto, while it is possible to obtain only part of the accurate contour line whichever color is selected for a reference color for binarization when a plurality of colors are included in the subject. For example, when a subject
1101
shaped like a human as shown in
FIG. 11
is to be cut out, if the reference color is set based on a color of a body part
1101
a
, the accurate contour line cannot be obtained in a head part
1101
b
, and if the reference color is set based on a color of the head part
1101
b
, the accurate contour line cannot be obtained in the body part
1101
a.
Thus, a new method as disclosed in Japanese Patent Publication (examined)63-5745 by the applicant has been suggested. That is, as shown in
FIG. 12
, the method is for setting a window frame (hereinafter referred to as a nozzle
1201
) on a display screen and, with moving the nozzle
1201
along a contour of a subject, binarizing image data in the nozzle
1201
. In this method, it is possible to obtain the accurate contour line of the entire subject
1101
by setting an appropriate reference color for each nozzle
1201
even when a plurality of colors are included.
By the way, in the embodiment shown in the above publication, an operator manually performs processing of moving the nozzle
1201
along the contour of the subject
1101
. That is, the operator roughly traces the contour of the subject
1101
, and from the approximate contour part obtained thereby, a system side traces an accurate contour line.
Specifically, in
FIG. 12
, the operator first moves the nozzle
1201
to a cutout starting position and sets a reference color. In response, the system side binarizes the image data in the nozzle
1201
to perform processing for obtaining a partial contour line in the nozzle
1201
. Next, the operator moves the nozzle
1201
in a direction shown by an arrow in the drawing along the contour of the subject
1101
, and further changes the reference color as required. In response, the system side binarizes the image data in the nozzle
1201
after movement to perform processing for obtaining a next partial contour line. Thereafter, the operator and the system repeat the above operation and processing to obtain contour lines of the subject
1101
and the background.
In the above new method, if the processing of moving the nozzle
1201
along the contour of the subject
1101
is performed by the system side, it is possible to further reduce a load on the operator thus perform prepress more efficiently. However, in the above publication and any other publications, processing of automatically moving the nozzle
1201
is not disclosed.
This may be because it is not easy to automatically move the nozzle
1201
on the grounds as follows. That is, the operator can intuitively distinguish the subject
1101
from the background when looking at the photographic image shown in FIG.
12
. However, the system side cannot distinguish which data belongs to the part of the subject
1101
and to the background part among the held image data. Thus, moving the nozzle
1201
along the contour of the subject
1101
is easy for the operator, but not for the system side because the system cannot recognize the contour.
SUMMARY OF THE INVENTION
Therefore, an object of the present invention is to provide an image cutout method and apparatus capable of automatically moving a nozzle when moving the nozzle on an image along a contour of a subject and binarizing image data in the nozzle to obtain the contour of the subject, and cutting out the image along the obtained contour line, and as a result, allowing efficient cutout without putting a load on an operator.
The present invention has the following features to solve the problem above.
A first aspect of the present invention is directed to a method for moving a window frame on an image along a contour of a subject and binarizing image data in the window frame to obtain a contour line of the subject, and cutting out an image along the obtained contour line,
at a start of cutout, the window frame being at a position including part of the contour line of the subject, the method comprising the steps of:
reading and converting the image into image data;
obtaining a partial contour line of the subject in the window frame by binarizing the image data in the window frame among the image data obtained by conversion; and
determining a direction for moving the window frame based on the obtained partial contour line and moving the window frame along the determined direction.
As described above, in the first aspect, based on the obtained partial contour line in the present window frame, the direction for moving the window frame is determined. Therefore, it is possible to move the window frame along the contour of the subject without operator′s operation of a pointing device and the like, and as a result, it is possible to efficiently perform cutout without putting a load on the operator.
According to a second aspect, in the first aspect,
at the start of cutout, the window frame is on the contour line of the subject, and
at the time of moving the window frame, the window frame is moved so that a center point of the window frame after movement is on one extreme point of the obtained partial contour line.
As described above, in the second aspect, the window frame is moved so that the center point of the window frame after movement is on one extreme point of the obtained partial contour line. Therefore, unlike in the case where a direction of a tangent of the obtained partial contour line is obtained and the window frame is moved along the direction, no complicated coordinate calculation is required and the window frame can be moved easily.
According to a third aspect, in the first aspect, the method further comprises the steps of:
zooming a partial area of the image including a part on which the window frame is put; and
determining a direction for moving the zoom area based on the obtained partial contour line and moving the area along the determined direction.
As described above, in the third aspect, also as to the area to be zoomed, based o
Dainippon Screen Mfg. Co,. Ltd.
Mariam Daniel G.
McDermott & Will & Emery
Tran Phuoc
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