JPS60117381A - Method and device for extracting contour - Google Patents

Abstract

PURPOSE:To shorten the time required for extracting contour lines, by extracting contour data in such a way that intermediate data point strings are stored by scanning a memory which stores contour point data one time and a point string buffer is operated by one time so as to connect the intermediate data point strings with each other. CONSTITUTION:Contour point data on a picture are stored in a contour point data memory 3 in the order of raster scan and, when the first contour point data are read out from the memory 3, the Y-coordinate value of a register 11 of terminal point of point string is set at a process decision circuit 12 in the first place. Then the contour point data are sent to a starting point detecting circuit 14 where the starting point of one side data point string is detected and sent to a point string buffer 10. A raster scan terminating signal S is given from the circuit 12 to a closed loop forming circuit 16 and the circuit 16 decides that the terminal point of the data point string is in a connected relation and reads out data of each data point string by scanning the data point strings in forward and backward directions. The read out data are extracted as contour data obtained when the outline of an object is traced in counterclockwise direction. The data are stored in a contour data memory 4.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field of the Invention The present invention uses a group of contour point data obtained in the screen scanning order for a binary image constituting the contour of an object as contour line data along the contour of the object. The present invention relates to a method and apparatus for extracting contour lines.

(2) Background of the technology In general, in order to extract the shape of an object from a binary image that forms the outline of the object, or to determine various parameters such as the position of the center of gravity of the object and the circumference of the outline of the object, calculations are required. From the viewpoint of ease of use, it is necessary to extract contour data arranged along the contour of the object.

(3) Prior art and its problems As a conventional method for extracting contours of this type, for example, as shown in FIG.
By setting an X-Y coordinate system in advance on a scene 1 where is displayed, and scanning the screen 1 2, a group of contour point data (Xl, Yl) (X2.Y2) . . . of the binary image G is obtained. (Xn
. Contour data (xAl, YAl) (x, y)...(xAn
, YAn) and stored in the line data memory 4. In this method, the contour line extraction process includes a starting point P(Xi,
Yi) and eight surrounding positions A that can be connected to this starting point.
Search the contour point data memory 3 for G to G,
After extracting the next contour point connected next to the starting point P, the next contour point connected next to the extracted contour point is extracted in the same manner as described above, and by repeating this procedure thereafter, The extracted contour points are sequentially stored in a contour data memory as contour data.

However, in such conventional contour line extraction methods, in order to extract the next contour point connected to a certain contour point, data values at all eight locations surrounding one contour point are extracted. Since the contour point data memory 3 has to be searched, the number of times the contour point data memory 3 is searched is required to obtain the final contour data, and the number of times the contour point data memory 3 is searched becomes enormous. There is a problem in that it takes a considerable amount of processing time.

(4) Purpose of the invention This invention has been made from the above viewpoints,
The object of the present invention is to provide a contour line extraction method and an apparatus thereof, which are intended to shorten the processing time associated with contour line extraction.

(5) Structure of the Invention The basic structure of the contour line extraction method according to the present invention is to extract a group of contour point data obtained in the order of screen scanning from a closed-loop binary image that constitutes the contour of an object. When extracting contour point data along the contour point data, the above contour point data group is stored in advance in a contour point data memory, and the contour point data read first from the contour point data memory is divided into a pair of data point strings from the other of the data point strings. At the stage when the start point of a pair of data point sequences is extracted, the contour point data connected to the end point of one of the data point sequences is detected as an extension point of the corresponding data point sequence. When arbitrary contour point data sequentially read from the point data memory is not connected to the end point of the data point sequence based on the previously read contour point data, the contour point data is used as one starting point of a new pair of data point sequences. By sequentially detecting the other starting point and its extension point in this new data point sequence in the same way as described above, the contour point data group read out sequentially from the contour point data memory is converted into a plurality of data point sequences. Once stored in the column buffer, the endpoint data of each data point sequence is compared to determine the connection relationship between each endpoint, and the data point sequences that can be connected are combined and stored in the contour data memory. The outline extraction method is characterized by the following.

The basic configuration of the device for carrying out the above method is to convert a group of contour point data obtained in the screen scanning order to a closed-loop binary image forming the contour of an object into contour data along the contour of the object. A contour line extraction device for extracting a contour line, which includes a contour point data memory that stores the contour point data group, and a point sequence buffer that sequentially stores contour point data sequentially read out from the contour point data memory as a predetermined data point sequence. , a point sequence end point register that sequentially stores each point sequence end point data corresponding to the end point of each data point sequence in this point sequence buffer, and a point sequence register that stores contour point data sequentially read from the contour point data memory. determining means for determining whether or not the contour point data is adjacent to the point sequence end point data in the point sequence buffer; and when the determining means determines that the contour point data is not connected to the point sequence end point data, Setting a space for storing a point sequence, and detecting the contour point data as one starting point in a pair of data point sequences,
a start point detection means for sending the contour point data to a point sequence buffer and a point sequence end point buffer; and a pair of start point detection means to be stored in the point sequence buffer when it is determined by the determination means that the contour point data is connected to predetermined point sequence end point data. Extended point detection means detects the contour point data as the other starting point in the data point sequence or an extension point of the corresponding data point sequence and sends it to the point sequence buffer and point sequence end point register; When stored in the column buffer, the end points of each data point sequence in the point sequence buffer are compared to determine the connection relationship between each end point, and each point sequence that can be connected is connected to create a closed loop contour line. The apparatus includes a closed loop forming means for extracting data, and a contour data memory for storing contour data from the closed loop forming means.

(6) Embodiments of the Invention Hereinafter, a contour line extraction method and apparatus according to the present invention will be explained in detail based on embodiments shown in the accompanying drawings.

FIG. 3 is a block diagram showing an embodiment of the contour extraction device according to the present invention.

In the same figure, 3 indicates a group of contour point data obtained in the screen scanning order for a closed-loop binary image that constitutes the outline of an object, as shown in FIG. 5(a), for example (see FIG. 5(b)). ) is the contour point data memory 4, for example, the fifth
A contour data memory 10 stores the contour point data group of FIG. 5 ('+1) as contour data along the outline of the object (see FIG.
), the contour line data group sequentially read out from the contour point data memory 3 is divided into two data point sequences TI and T2.
For example, the point sequence buffer 11 stored as
As shown in d) and (e), it is a point sequence end point register that sequentially stores each point sequence end point data corresponding to the end points of each data point sequence Tl, T2 in the point sequence buffer 10, and this point sequence end point The data consists of two X coordinate values (X, 1.X, 2) and one X coordinate value.

In this embodiment, 12 also determines whether the X coordinate value of the contour point data has changed compared to that of the previously read contour point data until the scanning of the contour point data memory 3 is completed. This is a process determination circuit that determines whether or not the scan goes down by one step. This is designed to update the X coordinate value in the point sequence end point register ll when the rask scan goes down by one step. When scanning is completed, a rask scanning completion signal S is output.

Reference numeral 13 denotes a start point detection circuit which refers to the X coordinate value of the point sequence end point register 11 and applies the contour point data read from the contour point data memory 3 to the point sequence buffer lo.
This sets up a space to newly store a pair of data point sequences in the point sequence buffer 1O, detects the contour data as the starting point of one of the pair of data point sequences, and stores it in the point sequence buffer 1O. At the same time, it is also sent to the point sequence end point register 11 as new initial point sequence end point data. On the other hand, 15 is an extension point detection circuit that operates when the connection point determination circuit 13 determines that the contour point data is connected to the data point sequence 2 in the point sequence buffer 10; If the other start point of the pair of data point strings is empty data, the contour point data is detected as the other start point of the pair of data point strings, and the start point of the pair of data point strings is set. If so, the contour point data is detected as an extension point of the corresponding data point sequence, and is sent to the point sequence buffer 10, and is also sent to the point sequence end point register 1 as the point sequence end point data to be updated.
1.

Further, reference numeral 16 is a closed loop forming circuit that is activated by the rask scan end signal S from the processing determination circuit 12, and this circuit compares the end points of each data point sequence in the point sequence buffer 10 and determines the connection relationship between each end point. is determined, each point string that can be connected is connected, and each point string in the point string buffer 10 is read out in a closed loop.

Next, the operation of the contour point extracting device according to this embodiment will be explained using FIGS. 3 to 5.

Now, the closed loop forming circuit that constitutes the outline of the object is shown in Figure 5 (
Assuming that the data is as shown in a), the contour point data memory 3 stores contour point data (X2.Y3) and (X2.Y3) in the rask scanning order on the screen, as shown in FIG.
l) Store the power. When the first contour point data (X2.Y3) is read out from the contour point data memory 3, first, in the processing determination circuit 12, the point sequence end point register! 1
The empty data X coordinate value of is set to Y3, and then
The above contour point data (X2tY2) is the connection point determination circuit 13
Since the X coordinate value of the point sequence end point register 13 is empty data, the contour point data (X2.Y
3) is determined that there is no connected data point sequence, and the contour point data (X2.Y3) is sent to the starting point detection circuit 14. Then, this starting point detection circuit 14 detects a pair of data point strings TI in the one point string buffer lo as shown in FIG. 5(d).
. ) in a pair of storage units (xTl
"T2). At this stage, point sequence buffer 1
The data point sequence T1 of 0 is stored with the contour data (X2.Y3) as the starting point, and the starting point of the data point sequence T2 is empty data, and the contents of the point sequence end point register 11 are as shown in FIG. 1).

Next, as shown in FIG. 5(b), when the next contour point data (X3.Y3) is read out from the contour point data memory 3, the processing determination circuit 12 reads out the next contour point data (X3.Y3).
The X coordinate value of 3) is compared with the X coordinate value of the point sequence end point register 11, but since both are equal, the X coordinate value of the point sequence end point register 1 is compared.
1 is not updated. Then, the above contour point data (X3.
Y3) is sent to the connection point determination circuit 13, the X coordinate value of this contour point data (X3.Y3) is stored in the point sequence end point register 1.
1, and the connection point determination circuit 13
This contour point data (x3゜5 Y3) is the point sequence end point (X, 1.X, 2) = (X2.X
2) c7) It is determined that the contour point data (X3.Y3) is connected to either one of the points A and A, and the contour point data (X3.Y3) is sent to the extension point detection circuit 15. Then, this extension point detection circuit 15 detects the contour point data (X3.Y3) as the starting point of the other data point sequence T2, sends it to the point sequence buffer 10, and
One storage section x7 of the point sequence end point register 11 uses the X coordinate value of the contour point data (X3.Y3) as point sequence end point data.
Store in 2. At this stage, each data point string TI, T2 in the point string buffer 10 is stored with the respective contour point data as the starting point, and the contents of the point string end point register 11 are stored as the fifth data point string.
It is as shown in Figure (2).

Furthermore, the next contour point data (X
1, Y2), the processing determination circuit 12 determines that the X coordinate value of the contour point data (Xi, Y2) is different from the X coordinate value of the point sequence end point register 11. Update the X coordinate value to Y2. Then, when the contour data (Xl, Y2) is sent to the connection point determination circuit 13, the connection point determination circuit 13 transmits the contour point data (xl.

It is determined that the contour point data (Xi, Y2) is connected to the point sequence end point data X, 1=X2, and the contour point data (Xi, Y2) is sent to the extension detection circuit 15. Then, the extension detection circuit 15 converts the contour point data (X3.Y3) into one data point sequence T1.
It is detected as an extension point of the point sequence and sent to the point sequence buffer 10, and at the same time, the X coordinate value of the contour point data (Xi, Y2) is stored in one storage section xTl of the point sequence end point register 11 as point sequence end point data. . Thereafter, processing is performed in the same manner as described above, and the contour point data (X3.Y2) is connected to the data point sequence T2, and at this stage the contents of the point sequence end point register 11 are as shown in FIG. 5(e) (3) It is shown in the figure below.

Then, when the contour point data (Xi, Yl) is read from the contour data memory 3, the X coordinate value of the point sequence end point register 11 is updated again, and the contour point data (Xi, Yl) is read out from the contour data memory 3.

Yl) is connected to the data point sequence T1, and furthermore, the contour point data (X2.Yl) read out last is also connected to the data point sequence T1.
1. At this stage, the scanning of the contour point data memory 3 is completed, and the point sequence buffer 10 is stored in the point sequence buffer 10 as shown in FIG.
) and each contour point data is stored in an array as shown in FIG. 5(d). The contents of the point sequence end point register 11 are as shown in FIG. 5(e) (4).

□ In this case, the processing determination circuit 12 gives the rask scanning end signal S to the closed loop forming circuit 16, and the closed loop forming circuit 16 generates the data point sequence TI, T2 (
7) It is determined that the end points (X2.Yl) (X3.Y2) are connected, and the data point sequence T1 is forwardly moved to the data point sequence T2.
is scanned in the opposite direction to read data of each data point sequence. This read data is extracted as contour line data along the contour of the object shown in FIG. 5(a) in a counterclockwise direction.

This contour data is then stored in the contour data memory (4) as shown in FIG. 5m.

In the above embodiment, the case where there are two data point sequences is explained, but if the present invention is applied to objects with complex contours, the contour point data that is still being processed can be Since the starting point detection path 14 will work,
The number of data point sequences increases accordingly, and contour line data can be extracted by appropriately combining each data point sequence. Further, the specific configuration of the device according to the above embodiment may be modified as appropriate.

(7) Detailed Description of the Invention As described above, according to the contour line extraction method and its device according to the present invention, a memory storing a group of contour point data is scanned once to extract an intermediate data point sequence. Contour line data can be extracted by storing the data in a point sequence buffer and operating the point sequence buffer only once to combine each data point sequence.

Therefore, it is possible to speed up the processing time associated with contour data extraction.

[Brief explanation of drawings]

9. FIG. 1 is an explanatory diagram showing an example of a conventional contour extraction method, FIG. 2 is an explanatory diagram of the principle used in the contour extraction process, and FIG. 3 is an implementation of the contour extraction device according to the present invention. A block diagram showing an example, FIG. 4 is a flowchart showing the basic operation of the contour line extraction device shown in FIG. 3, FIG. 5 shows a specific operating state of the contour point extraction device shown in FIG. (a) shows an example of a binary image constituting the outline of an object.
Figure (b) shows the contents of the contour point data memory, and Figure 5 (c) shows the contents of the contour point data memory.
The order in which data is stored in the point sequence buffer is shown in Figure 5(d).
is the point sequence buffer 3...contour point data memory 4...contour data memory 10...point sequence buffer 11...point sequence end point register 12...processing judgment circuit 13...connection point judgment Circuit (judgment means) 0 14...Start point detection circuit (means) 15...Extension point detection circuit 18...Closed loop formation circuit Patent applicant Fujitsu Limited Gω Seal [L] (4-) (51)

Claims (1)

[Claims] 1) When extracting a group of contour point data obtained in the screen scanning order for a closed-loop binary image constituting the contour of an object as contour point data along the contour of the object, the above-mentioned group of contour point data is stored in the contour point data memory in advance, and the contour point data read out first from the contour point data memory is set as the other starting point of the pair of data point sequences, and the starting point of the pair of data point sequences is extracted. At this stage, the contour point data connected to the end point of any of the data point sequences is detected as an extension point of the corresponding data point sequence, while any contour point data sequentially read from the contour point data memory is detected first. When not connected to the end point of the data point string based on the contour point data read out, the contour point data is used as one starting point of a new pair of data point strings, and the other starting point and its extension point in this new data point string are By performing sequential detection in the same way as described above, the contour point data group sequentially read out from the contour point data memory is stored in the point sequence buffer as a plurality of data point sequences, and then the end point data of each data point sequence is A contour line extraction method characterized in that a connection relationship between each end point is determined by comparison, and data point sequences that can be connected are combined and stored in a contour data memory. 2) A contour line extraction device that extracts a group of contour point data obtained in screen scanning order for a closed-loop binary image constituting the contour of an object as contour line data that follows the contour of the object, the contour point data group being a point sequence buffer that sequentially stores the contour point data sequentially read out from the contour point data memory as a predetermined data point sequence; A point string end point register that sequentially stores each corresponding point string end point data and a determination as to whether contour point data sequentially read from the contour point data memory are adjacent to point string end point data in the point string register. By means of judgment and this means of judgment.”
When it is determined that the contour point data described above is not connected to the point sequence end point data, a space is set in the point sequence buffer to store the pair of data point sequences, and one starting point in the pair of data point sequences is set. starting point detection means for detecting the contour point data and sending it to a point sequence buffer and a point sequence end point buffer; Extended point detection means for detecting the contour point data as the other starting point in the pair of data point sequences to be stored in the sequence buffer or as an extension point of the corresponding data point sequence, and sending this to the point sequence buffer and point sequence end point register. Then, when all the contour point data is stored in the point sequence buffer, the end points of each data point sequence in the point sequence buffer are compared to determine the connection relationship between each end point, and each point sequence that can be connected is determined. closed loop forming means for extracting closed loop contour data by combining the
A contour extraction device comprising a contour data memory for storing contour data from the closed loop forming means.