JPH10255061A - Object shape identifying device and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an object shape identifying device which locally makes area specification in figure data that shows the flat plane shape of an object and effectively identifies whether it is an object or space without tracing a part one by one even when there is uncontinuous part in a contour line of figure data in the designated area. SOLUTION: A single and closed virtual line B is formed connecting among plural coordinate data (Q1, Q2,...) which are inputted in a local area by a keyboard, and intersections with a contour line A of figure data are calculated, a line drawing is formed, tracking the line A or the line B in the direction of decision from an intersection 1 toward other intersections by deciding a line drawing forming direction according to coordinate data, a figure area C that is surrounded by the line drawing is formed, repeating an operation that selects the line drawing including other corresponding intersections which are located at a position that is rotated at prescribed degrees in the line drawing forming direction against a line drawing including the intersection 1 at the other intersections, and the inside of the area C is identified and displayed on a graphic display, assuming that the inside of the area C is a read frame.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CAD (Comp
The plane shape of an object such as a lead frame drawn by an outer Aided Design device is stored as graphic data, and a local area of the object is designated.
The present invention relates to an object shape identification apparatus and method for reading graphic data in the designated area and determining whether the inside or outside of the outline is an object or a space.

[0002]

2. Description of the Related Art Conventionally, in the inspection process of a lead frame used for a semiconductor package, for example, when an inspection such as a lead width of an inner lead is performed, an inspection in which a marker serving as a scanning line is provided on an inner lead portion to be measured in advance. The data is provided to the inspection device, and the inspection device reads the intersection of the marker and the inner lead portion according to the inspection data, measures the actual width of the lead portion at the designated position, and performs inspection of the lead frame. The system is built to do so. Using graphic data indicating the outline shape of the lead frame drawn on the CAD device,
When creating inspection data, the operator visually recognizes whether the CAD data is an inner lead portion or a space portion including a hole from graphic data read and stored in an arithmetic processing device such as a personal computer. However, a scanning line serving as a marker is provided on the graphic data. Since the measurement of the inner lead portion is given in a data format of measuring from what number of intersections between the scanning line and the inner lead portion, it is desirable to extend the scanning line as long as possible.

Generally, in order to determine the planar shape of an object from graphic data, it is necessary to recognize a group of graphic elements forming an outer shape, and to recognize a group of closed graphic elements existing inside the outer shape. After visually recognizing the relationship, it is possible to determine on which side of the contour the object and the space exist for each graphic element. For example, QFP (Quu
ad Flat Package) or DIP (Dual
When determining the shape of an inner lead portion formed radially from a die pad in a lead frame used for an Inline Package or the like, the outer shape is first visually recognized. Next, it is recognized whether there is a closed shape in a portion surrounded by the outer shape, and if there is a closed shape, it is determined that the hole is a hole. Thus, after recognizing in advance whether the starting point of the line segment to be drawn is on the object (lead) or on the space (hole), the direction intersecting the inner lead (the width direction of the lead frame) Draw a line segment. When the start point of the line segment starts from the space, the marker is used by using an algorithm in which the space between the first and second intersections is an object and the space between the second and third intersections is a space. Inspection data was created.

[0004]

Now that semiconductor devices have been miniaturized and highly integrated, and the number of pins in the lead frame has increased and the pitch has been reduced to a fine pitch, the entire graphic data of the lead frame drawn by the CAD device is directly transferred. It is complicated and difficult to select a specific inner lead portion and visually write a scanning line. Therefore, an inner lead portion of the graphic data must be locally designated and taken out, and a method of identifying the lead portion or the space must be taken. If there is a closed graphic element in the designated area, it is necessary to determine the object or space by tracing the entire outer shape including the closed graphic element, but in the designated area, the outline is continuous. In many cases, it does not take much time to identify the inner lead portion or the space portion. For example, in a certain designated area, when there are n closed graphic elements in which a contour line is interrupted, it is necessary to follow the shape one by one in order to recognize the external shape surrounding the closed graphic element. It is necessary to perform a process of identifying the lead portion or the space portion by tracing the contour line at most n × n times, which is inefficient.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art, and to locally designate an area in graphic data indicating the planar shape of an object, and to discontinuously connect the contour of the graphic data in the designated area. It is an object of the present invention to provide an object shape identification apparatus and method for efficiently identifying an object or space without tracing each part even if it exists.

[0006]

The present invention has the following arrangement to achieve the above object. That is, first input means for inputting graphic data relating to the planar shape of an object, second input means for inputting designation data including area designation data and coordinate data, and data inputted from the first and second input means. A line drawing output unit for outputting graphic data read from the storage unit and a line drawing created in a display area including the graphic data; and a control program stored in the storage unit. Reading the figure data in the designated area from the storage means in accordance with the area designation data inputted from the second input means, and connecting the plurality of coordinate data inputted in the designated area from the second input means; A single closed virtual line is formed to determine an intersection with the contour line of the graphic data, and a line drawing forming direction is determined based on the coordinate data to determine one intersection. A line drawing is formed while following a contour line or a virtual line toward another intersection in the determination direction, and the other at a position rotated by a predetermined angle in the line drawing forming direction with respect to the line drawing including the one intersection at another intersection. Control means for forming a graphic area surrounded by the line drawing while repeating the operation of selecting a line drawing including the intersection of the above, and assuming that the inside of the graphic area is an object, the control means for identifying and displaying to the line drawing output means. It is characterized by.

If the control means determines that the line drawing forming direction is a counterclockwise direction, the control means includes a line drawing including another intersection at a position rotated by the maximum counterclockwise angle with respect to the line drawing including the one intersection. Is selected, and when it is determined that the line drawing forming direction is the clockwise direction, a line drawing including another intersection at a position rotated clockwise by the maximum angle with respect to the line drawing including the one intersection is selected and the graphic area is selected. It is desirable to control so as to form. Further, the control means traces a contour line or a virtual line from the first intersection in the line drawing forming direction when the starting point of the virtual line is assumed to be a space portion, and when the starting point is assumed on the object, It is preferable to form a graphic area while following a contour line or a virtual line in the line drawing forming direction from the intersection of the two. Further, when there is a figure inside the figure area, it is preferable that the control means identifies the part partitioned by the figure as an object or a space by following the figure.

In the object shape identification method, graphic data indicating the planar shape of the object is input from the first input means, the graphic data is stored in the storage means, and the control program stored in the storage means is used. When a local area of the object is designated by the second input means, graphic data corresponding to the designated area is read out. When a plurality of coordinate data are inputted into the designated area by the second input means, the coordinate data is connected. To form a single closed virtual line to determine the contour line and the intersection of the figure data, determine the line drawing forming direction based on the coordinate data, and determine the outline from one intersection toward another intersection in the determination direction. A line drawing is formed while following a line or a virtual line, and the line drawing including the other intersection at a position rotated by a predetermined angle in the line drawing forming direction with respect to the line drawing including the one intersection at another intersection. Repeating an operation for selecting, characterized in that identification assuming object graphic area surrounded by the line drawing.

If it is determined that the line drawing forming direction is a counterclockwise direction, a line drawing including another intersection located at a position rotated by the maximum counterclockwise angle with respect to the line drawing including the one intersection is selected. When it is determined that the line drawing forming direction is the clockwise direction, a line drawing including another intersection at a position rotated clockwise by the maximum angle with respect to the line drawing including the one intersection is selected to form a graphic area. It is desirable. Further, when forming the graphic area, if the starting point is assumed to be a space, the contour or virtual line is traced in the line drawing forming direction from the first intersection,
When the starting point is assumed on the object, it is preferable to follow the contour or the virtual line in the line drawing forming direction from the second intersection. Also,
When there is a graphic in the graphic area, it is desirable to identify a part partitioned by the graphic as an object or a space by tracing the graphic.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In this embodiment, a shape identification device and method for recognizing a local planar shape using a QFP lead frame as an object will be described. FIG. 1 is a block diagram showing a configuration of a lead frame shape identification device, FIG. 2 is a flowchart showing a lead frame shape identification process, FIG. 3A is a schematic explanatory view showing a lead frame shape identification process, and FIG.
(B) and (c) are explanatory diagrams showing a method of selecting a line image to be followed next at each intersection, FIG. 4 is an explanatory diagram showing a local shape of an identified lead frame, and FIG. 5 is a plan view of a QFP lead frame. FIG. 6 is an explanatory diagram showing a method for determining the line drawing forming direction.

First, the configuration of the lead frame shape recognition device will be described with reference to the block diagram shown in FIG. In FIG. 1, reference numeral 1 denotes a CAD system as first input means, which generates and outputs graphic data relating to a planar shape of a lead frame. Graphic data relating to the planar shape of the lead frame is input from the CAD system 1. Reference numeral 2 denotes a keyboard as second input means, to which area designation data for extracting a local area from the graphic data and designation data including a plurality of coordinate data for forming a virtual line to be described later are inputted. The first and second input means may be an external storage device or an externally connected external computer system in addition to the CAD system 1 and the keyboard 2.

Reference numeral 3 denotes a RAM as a part of the storage means, which stores the graphic data input from the CAD system 1. Also, based on the graphic data, a microprocessor (MPU) as a control means described later logically configures a virtual plane corresponding to the lead frame in a storage area of the RAM 3, and the MPU designates a designated area designated on the virtual plane. Is generated, and the graphic data on the virtual plane is stored. RA above
The M3 has a function as a storage unit for storing commands and data input from the CAD system 1 and the keyboard 2, and also has a function as a work area of an MPU, which will be described later. Information, calculation results, and the like are temporarily stored. In addition, instead of the above RAM3,
An external memory such as a flexible disk or an IC memory card can also be used.

Reference numeral 4 denotes a ROM as a part of the storage means, in which an operating system of an MPU to be described later, a control program of a lead frame shape identification device, control data, and the like are stored in advance. Note that an external memory such as a flexible disk or an IC memory card can be used without storing the control program, control data, and the like in the ROM 4. Reference numeral 5 denotes a graphic display as line drawing output means, which outputs and displays a line drawing created based on the designated data input from the keyboard 2. The line drawing output means includes a graphic display 5.
In addition, a printer, an external storage device, and the like can be adopted.

Reference numeral 6 denotes an MPU serving as control means. When area designation data is input from the keyboard 2 based on a control program stored in the ROM 4, graphic data existing in the designated area is read from the RAM 3. When a plurality of coordinate data is input from the keyboard 2, a control is performed so that a line image is written in a display area including the graphic data and displayed on the graphic display 5. More specifically, graphic data in the designated area is read out from the RAM 3 in accordance with the area designation data input from the keyboard 2, and a plurality of coordinate data input into the designated area from the keyboard 2 are connected. A single closed virtual line is formed to determine an intersection with the outline of the graphic data, a line drawing forming direction is determined based on the coordinate data, and a contour is formed from one intersection toward another intersection in the determination direction. Forming a line drawing while tracing a line or a virtual line, and selecting a line drawing including the other intersection at a position rotated by a predetermined angle in the line drawing forming direction with respect to the line drawing including the one intersection at another intersection. A graphic area surrounded by line drawings is formed while repeating, and the graphic display 5 is identified and displayed on the graphic display 5 assuming that the graphic area is an object.

The process for identifying the shape of the lead frame 7 will now be described with reference to the flowchart shown in FIG.
This will be specifically described with reference to FIGS. In FIG. 2, when the lead frame shape discriminating apparatus is started (step S1), the MPU 6 reads the control program stored in the ROM 4 and makes preparations such as clearing the RAM 3. First, the MPU 6 reads the graphic data of the lead frame 7 from the CAD system 1 and stores it in the RAM.
3 (step S2).

Next, as shown in FIG.
Pointing the local area 8 in the planar shape of the lead frame 7
If set, the read frame existing in the local area 8
Of the graphic data (contour line A) of the
Generated on the virtual plane (see FIG. 3A) and
It is stored in the RAM 3 (step S3). And said
From the keyboard 2 in the local area 8, the starting point position (Q
Coordinate data forming a single closed virtual line B including 1)
(Q2 to Q6) are input. In this embodiment, the starting point position
(Q1) is assumed to be in the space, and the coordinate data
The way to take the data is based on the lead
Intersection between the outline A (solid line) and the imaginary line B (dashed line) of the frame 7
(Step S4). Ma
The line drawing forming direction is input from the keyboard 2.
Based on the coordinate data (Q1 to Q6), the MPU 6
It is determined dynamically (step S5). For example, as shown in FIG.
As shown, the coordinates (x₁, Y₁), (X_Two, Y_Two),
(X_Three, Y _Three) Is specified counterclockwise in the order of →→
Suppose that the area of the shaded area A is the area of three trapezoids
Calculate the area A = (y₁+ Y_Two) (X_Two-X₁) / 2 + (y_Two+
y_Three) (X_Three-X_Two) / 2 + (y_Three+ Y₁) (X₁-X
_Three) / 2. The sign of the area A in this case is-. Reverse
If the above coordinates are specified clockwise, the area A
The sign is +. This is (x_{n + 1}-X_n) Sign, ie
Because it depends on the specified rotation direction of the coordinate data (~)
is there. The coordinate data (Q1
To Q6) can be determined. However, specified
Line segments connecting the coordinates that have been set do not have intersections
It is necessary to keep in mind that the above coordinate data is entered
is there. The line drawing direction is input together with the coordinate data.
However, considering operability and input mistakes, the coordinates
Preferably, it is automatically determined by data input.

Next, as shown in FIG.
Are coordinate data (Q1 to Q1) input from the keyboard 2
Q6) are connected to form a virtual line B, and then intersections (P1 to P14) of the outline A (solid line) and the virtual line B (broken line) are obtained (step S6). Next, a line drawing is drawn while tracing the virtual line B toward another intersection (P2) from the first intersection (P1) toward the line drawing forming direction (the counterclockwise direction in this embodiment) determined. At this time, when the starting point (Q1) is assumed to be a space, the tracing starts from the first intersection (P1), and when the starting point (Q1) is assumed on the lead frame 7, the second intersection (P2) ) To start tracing (step S7).

FIG. 3B shows a method of selecting a line image to be traced at each intersection of the contour line A and the virtual line B.
This will be described with reference to FIG. In FIG. 3C, when it is determined that the line drawing forming direction is counterclockwise, for example, a vector V4 at a position rotated at the maximum counterclockwise direction with respect to the vector V1 at the intersection (P) is selected. I do. In FIG. 3B, when it is determined that the line drawing forming direction is clockwise, the vector V4 at the position rotated by the maximum angle clockwise with respect to the vector V1 is selected.

Accordingly, in the case of FIG. 3A, since the line drawing forming direction is determined to be counterclockwise, the line segment L1 forming the virtual line B is traced counterclockwise from the intersection (P1), and the intersection (P2 )
When the direction of the next line image to be traced is determined, the line segment L2 at the position rotated by the maximum angle in the counterclockwise direction with respect to the line segment L1 including the intersection (P1) is selected. Similarly, when determining the direction of the next line image to be traced at the intersection (P13), a line segment L3 at a position rotated by the maximum angle counterclockwise with respect to the line segment L2 including the intersection (P2) is selected. Similarly, when determining the direction of the next line image to be traced at the intersection (P14), the line segment L4 at the position rotated by the maximum angle in the counterclockwise direction with respect to the line segment L3 including the intersection (P13) is selected. Intersections (P1), (P2), (P13), (P14)
Are formed, and a graphic area C composed of line segments L1, L2, L3, L4 connecting. This is because when the line drawing forming direction is determined to be clockwise, the line segment L3 at the position rotated by the maximum angle clockwise with respect to the line segment L4 including the intersection (P1).
Is repeated, and a graphic area C is similarly formed (steps S8 and S9).

The object and the space inside and outside the graphic area C are determined to be objects on the left side of the traveling direction when the intersection is traced counterclockwise. When the intersection is traced clockwise, it is determined that the right side of the traveling direction is the object. Therefore, in the case of the closed graphic area C shown in FIG. 3A, it can be determined that the inside (hatched portion) of the quadrilateral is an object (inner lead portion).

Next, as shown in FIG. 4, it is determined whether or not a graphic element D having a start point and an end point is included in the graphic area C (step S10), and the graphic element D is included. In this case, it is determined that the object is a hole when the object is traced from the starting point and returns to the starting point, that is, when the element is a closed graphic element. When tracing the figure element D, when tracing counterclockwise, the right side of the line drawing (line segment, curve, etc.) is determined to be an object, and when tracing clockwise, the line drawing (line segment, curve) is determined. Is determined to be an object (step S1).
1).

Such an operation is performed by using the contour line A and the virtual line B
Is performed on one or a plurality of graphic areas C formed by having intersections, and a flag is set on an area determined to be the lead frame 7 or the color is changed on the graphic display 5 to change the lead frame 7. Can be clearly identified (step 12).

Also, the portion surrounded by the outline A that is continuous with the graphic area C identified in the local area 8 may be determined to be the lead frame 7. Alternatively, an area adjacent to the area may be identified as long as it is visually recognizable. Also, when assuming that the starting point (Q1) of the virtual point B is on the lead frame 7 or a space, it is assumed that there is a discrepancy between the designation of the operator and the actual lead frame because it is in the local area 8. However, by comparing discrepancies with the data identified in any of the local areas 8 in which the start point (Q1) position is clearly on the lead frame 7 or in the space, the lead frame 7 and the space can be distinguished. By exchanging them and displaying them on the graphic display 5, consistency can be obtained. In addition, the coordinate data (Q1 to Q
For the graphic in the local area 8 that cannot be determined by the virtual line B formed by 6), the virtual line B is
It is only necessary to specify again so as to have an intersection with and determine in the same procedure.

The contour line A included in the local area 8
Has been described using polygons formed by line segments, processing can also be performed when a part of the line drawing includes a curve such as an arc. In this case, there is a suspicion that the rotation angle cannot be uniformly determined by a combination of a line segment and an arc, or an arc and an arc in determining the direction of following the graphic area C from the intersection of the outline A and the virtual line B. Occurs. However, since the curve such as the arc is also formed by the continuation of a plurality of dot data, the line segment connecting a point in a certain order from the intersection is approximated to the rotation angle to the arc in a pseudo manner, so that the traveling direction is It is possible to obtain the maximum and minimum rotation angles with respect to, and it is possible to determine in the same procedure.

As described above, after judging whether the graphic data in the local area 8 is the lead frame 7 or the space portion, the inspection data of the lead frame can be created by using the graphic data, for example. is there. That is, after identifying the local area 8 to be inspected in the lead frame 7 to identify the inner lead portion or the space portion, the marker by the scanning line intersecting the inner lead portion is drawn as long as possible, Inspection data for measuring a lead width between certain intersections can be generated.

According to the above configuration, graphic data existing in a designated area designated by an operator is extracted from graphic data having a complicated and fine outer shape such as inner leads of a fine pitch lead frame. Even if there is a discontinuity in the outline of the graphic data in the designated area, it is possible to efficiently discriminate between an object and a space without following the discontinuity. In particular, when a closed graphic element is included in the designated area, it is possible to identify an object or a space without recognizing the entire contour line including the closed graphic element. Can be greatly reduced. Specifically, if there are n closed graphic elements,
Conventionally, n × n times of processing were required. However, according to the present invention, it is necessary to perform at most n times of processing for designating the virtual line B including the above n graphic elements. Can be determined.

Although various preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments. For example, the object is not limited to the shape of the inner lead of the lead frame. This is effectively used when the shape of another object is identified in the local area. Also,
The graphic data obtained by judging whether the object or the space portion is not limited to inspection data, and may be used for generating other data such as design data. Of course, modifications can be made.

[0028]

As described above, according to the present invention, graphic data corresponding to a designated area designated by the input means is read out from the storage means, and a plurality of coordinate data are inputted into the designated area including the graphic data. Forming a single closed virtual line by connecting the coordinate data to determine an intersection with a contour line of the graphic data, determining a line drawing forming direction based on the coordinate data, and determining a determination direction from one intersection. A line drawing while tracing a contour line or a virtual line toward another intersection, and the other intersection at a position rotated by a predetermined angle in the line drawing forming direction with respect to the line drawing including the one intersection at the other intersection By forming a graphic area surrounded by the line drawing while repeating the operation of selecting the line drawing including the, and assuming that the inside of the graphic area is an object, the line drawing output means is identified and displayed,
Of the graphic data having a complicated and fine outer shape, the graphic data existing in the designated area designated by the operator is taken out, and even if there is a discontinuity in the contour line of the graphic data in the designated area, this is taken out. An object or a space can be efficiently identified without tracing each time. In particular, when a closed graphic element is included in the designated area, it is possible to identify an object or a space without recognizing the entire contour line including the closed graphic element. Can be greatly reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a lead frame shape identification device.

FIG. 2 is a flowchart showing a lead frame shape identification process.

FIG. 3 is a schematic explanatory diagram showing a process of identifying the shape of a lead frame and an explanatory diagram showing a method of selecting a next line image to be followed at each intersection.

FIG. 4 is an explanatory view showing a local shape of an identified lead frame.

FIG. 5 is a plan view of a lead frame for QFP.

FIG. 6 is an explanatory diagram illustrating a method of determining a line drawing forming direction.

[Explanation of symbols]

 A contour line B virtual line C graphic area D graphic element 1 CAD system 2 keyboard 3 RAM 4 ROM 5 graphic display 6 MPU 7 lead frame 8 local area

Claims (8)

[Claims] A first input unit for inputting graphic data relating to a planar shape of an object; a second input unit for inputting designation data including area designation data and coordinate data; and an input from the first and second input units. Storage means for storing the obtained data, line drawing output means for outputting graphic data read from the storage means and line drawings created in a display area including the graphic data, and control stored in the storage means Based on the program, the graphic data in the designated area is read out from the storage means in accordance with the area designation data input from the two input means, and a plurality of coordinate data input into the designated area from the second input means are read out. To form a single closed virtual line to determine the intersection with the contour line of the graphic data, determine the line drawing forming direction based on the coordinate data, and A line drawing is formed while tracing a contour line or an imaginary line from the point toward another intersection in the determination direction, and at another intersection, the line drawing including the one intersection is rotated by a predetermined angle in the line drawing forming direction. Control means for forming a graphic area surrounded by the line drawing while repeating the operation of selecting the line drawing including the other intersection, and assuming that the inside of the graphic area is an object, to the line drawing output means for identification display. An apparatus for identifying the shape of an object. 2. When the control unit determines that the line drawing forming direction is the counterclockwise direction, the control unit includes a line drawing including another intersection at a position rotated by the maximum counterclockwise angle with respect to the line drawing including the one intersection. Is selected, and when it is determined that the line drawing forming direction is the clockwise direction, a line drawing including another intersection at a position rotated clockwise by the maximum angle with respect to the line drawing including the one intersection is selected and the graphic area is selected. 2. The object shape identification apparatus according to claim 1, wherein control is performed so as to form. 3. The control means according to claim 1, wherein when the starting point of said virtual line is assumed to be a space, a contour or virtual line is traced in a line drawing direction from a first intersection, and said starting point is assumed to be on an object. 3. The object shape identification device according to claim 1, wherein the figure area is formed while following a contour line or a virtual line from the second intersection in the line drawing forming direction. 4. The control device according to claim 1, wherein, when there is a graphic inside the graphic area, the control means identifies a portion partitioned by the graphic as an object or a space by following the graphic. 4. The object shape identification device according to claim 1, 2, or 3. 5. A graphic data indicating a planar shape of an object is inputted from a first input means, the graphic data is stored in a storage means, and an object is inputted from a second input means based on a control program stored in the storage means. If you specify the local area of
When the graphic data corresponding to the designated area is read and a plurality of coordinate data are input into the designated area from the second input means, a single closed virtual line is formed by connecting the coordinate data to form the graphic data. , A line drawing direction is determined based on the coordinate data, and a line drawing is formed while tracing a contour line or an imaginary line from one intersection to another intersection in the determination direction. Assuming that the object in the graphic area surrounded by the line drawing is repeated while repeating the operation of selecting the line drawing including the other intersection at a position rotated by a predetermined angle in the line drawing forming direction with respect to the line drawing including the one intersection. And causing the line drawing output means to perform identification display. 6. When the line drawing forming direction is determined to be a counterclockwise direction, a line drawing including another intersection located at a position rotated by the maximum counterclockwise angle with respect to the line drawing including the one intersection is selected, When it is determined that the line drawing forming direction is the clockwise direction, a line drawing including another intersection at a position rotated clockwise by the maximum angle with respect to the line drawing including the one intersection is selected to form a graphic area. 6. The method according to claim 5, wherein the shape of the object is identified. 7. When forming the graphic area, if a starting point is assumed to be a space, a contour line or an imaginary line is traced in the line drawing forming direction from the first intersection, and a starting point is assumed to be on an object. 7. The object shape identification method according to claim 5, wherein the object traces an outline or a virtual line from the second intersection in the line drawing forming direction. 8. When there is a graphic in the graphic area, by tracing the figure, a portion partitioned by the graphic is identified as an object or a space.
8. A method for identifying a shape of an object according to claim 7.