JPH01243188A - Contour detector - Google Patents

Abstract

PURPOSE:To easily extract a contour by preparing a command string to contain each information of the connection relation between contour picture elements and the arrangement pattern of picture element data and preparing a table to systematize contour elements based on it. CONSTITUTION:A contour extracting extracting part 1 fetches binarized picture element data corresponding to the white and black obtained by raster-scanning a subject, the picture element data of longitudinal and lateral 2X2 picture elements are successively extracted along a scanning line, the command string for detecting the contour is prepared based on the picture element data, and it is outputted to a contour analyzing part 2 in a following stage. The contour analyzing part 2 updates the descriptions of a contour element table, a contour management table, and a contour connection table in a table storing part 3 based on the command string. Thus, the contour can be easily extracted.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a device for detecting the outline of a binary image.

B1 Summary of the Invention The present invention is an apparatus for detecting a contour corresponding to a black-and-white boundary based on binary pixel data corresponding to black and white obtained by raster scanning a subject, which detects pixel data of 2 pixels x 2 pixels. Based on the pixel data extracted before line 1, for example, find the connection relationship between the contour pixels in the Y direction of the Lascus Gyan, create a command string containing information on this relationship and the arrangement pattern of the pixel data, and then By creating a table that serializes contour elements based on these command sequences, image memory capacity, hardware configuration, and processing time are not affected by image size or resolution, making contour extraction easier. It was designed so that it could be done.

C1 Conventional technology When processing patterns such as characters and figures, for example, converting objects such as documents and drawings into black and white binary image data (input pattern) obtained by operating them with an input device such as an image scanner. Then, contour pixels of the object are extracted from this binary image data, and information compression processing and object recognition processing are performed.

Among these, the conventional method for extracting contour pixels of an object from binary image data exhibits an operation as shown in FIG. 25. This can be described using the following process flow.

(1) First, all binary image data is stored in the dedicated image memory M.

(2) Next, search the memory M for a point, for example, point P1, which is the starting point of the contour of T to be detected.

■Sequentially track and extract points adjacent to this point P, and
Extract the contour pixels of.

D1 Problem to be solved by the invention J: In the conventional contour pixel extraction method, 1
A dedicated memory is required to store binary image data for a screen. This has the disadvantage that the larger the size of the input document or drawing, or the higher the resolution, the larger the memory capacity.

In terms of hardware configuration, the image memory grows in proportion to the vertical and horizontal sizes of the input image, so in some cases it may be necessary to configure the configuration to take into account the addition of a J memory board. For example, when targeting AO size Image memory is A4
It requires 16 times the capacity as a size image memory, and even when it is configured with one A4 size memory board, 16 AO size memory boards are required.

Next, processing time also has a significant impact. Conventional methods require waiting time until one screen's worth is stored in the image memory, and in order to extract the contour, it is necessary to perform sequential tracking using software, which also depends on the image of the target image. The processing time will be affected in proportion to the size and resolution.

To summarize the above, with conventional contour extraction methods, simply increasing the image size or increasing the resolution has drawbacks that affect hardware configuration, processing time, etc., and also has the disadvantage of affecting product appearance, price, etc. was also an influential factor.

The present invention has been made to solve these problems, and is capable of easily extracting contours without being affected by image memory capacity, hardware configuration, or processing time, and image size or resolution. An object of the present invention is to provide a contour detection device that can perform the following steps.

Means for Solving Problem E2 FIG. 1 is a diagram showing the configuration of the present invention, which is an IL1 contour extraction section. As shown in FIG. 2, this contour extraction unit I has two
The converted pixel data is taken in, pixel data of 2 pixels x 2 pixels in the vertical and horizontal directions are sequentially extracted along the scan line, a command string for contour detection is created based on this pixel data, and the command sequence for contour detection is created and sent to the subsequent contour analysis section 2. Output to. The contour analysis section 2 updates the descriptions in the contour element table, contour management table, and contour connection table in the table storage section 3 based on the command string.

Here, the contour element corresponds to a vector connecting two adjacent black pixels, and the contour is constructed by connecting these. As shown in Fig. 3, the contour element table is a table in which a unique code is attached to each contour element and a contour made up of a group of these contour elements, and for each contour element, its coordinates, direction, and the contour element to which it belongs are assigned. This is to describe the code of the contour element and the code of other contour elements connected before and after the contour element, respectively. The contour management table is for recording the codes of contour elements located at the tip and end of each contour, as shown in FIG. This is for describing the coordinates arranged in the direction, the code of the end-connected contour element whose front end or rear end exists at the coordinate, and the distinction between the front and rear ends of the end-connected end of the contour element in correspondence.

The command sequence output from the F1 action contour extraction unit I includes information on the connection relationship between pixels and contour elements related to the 2 pixel x 2 pixel pixel data extracted at that time, and the black and white color of the pixel data. It is formed by combining a connection/pattern code containing information on the array pattern and a coordinate code indicating the X coordinate of the pixel data.

An example of the connection relationship is shown in FIG. 6. When the pixel data of 2 pixels x 2 pixels surrounded by the large frame in FIG. This information indicates that the front end is connected. In this example, the coordinates of the pixel data are a pixel P located at the lower right when facing the page.

The coordinates are taken. Also, when the pixel data surrounded by the large frame in the same figure (b) is imported, the
This is information that the rear end of the contour element located at the coordinate Xn-+ one position before the coordinate is connected. Note that O in Figure 6
A frame with a mark indicates a black pixel, and a frame without an O mark indicates a white pixel.

For example, if we focus on the large frame in Fig. 6(a), the connection/pattern code in this case includes ``double connection information and information on the black and white array pattern within the large frame, and the command string includes this connection/pattern code. This is a combination of a pattern code and a coordinate code indicating the X coordinate of pixel P1. Note that this coordinate code can also be generated on the contour analysis section 2 side in synchronization with the timing of fetching the command sequence.

When the command string obtained in this way is taken into the contour analysis section 2, the following processing is performed. Assuming that a command string related to the pixel data of the large frame in Figure 7 is imported, the contour element Cj shown by the dotted line is registered in the contour element table, its direction and coordinates are entered, and the contour element Cj is
Enter the numbers of other contour elements connected before and after j in the connected element number column. In this case, since the contour element Cj is located in front of the contour element Cj, Ci is written in the rear connection column related to the column of the contour element Cj, and Ci is written in the front connection shelf related to the column of the contour element Cj. Furthermore, the number of the contour to which the contour element Cj belongs, Si in this example, is entered in the contour number column. Regarding the direction of the contour elements, for example, in the case of 8 connections, as shown in FIG.
1 to a8 are defined, and in the case of four connections, four directions, up, down, left and right, are defined. Then, for the contour number Si in the contour management table, change the tip contour element number column from 01 to Cj.
At the same time, the forward connection field of the last connected contour element number is updated from 01 to Cj for the X coordinate of the relevant pixel data in the contour connection table (J).By the way, in actual processing, the contour element Ci Since the shear element connected to the front connection shelf is specified by the contour connection table, the description of Cj of the front connection shelf in the contour element number Cj column of the contour element table is performed with reference to the contour connection table.

In the following, when two contours generated separately as the raster scan progresses are connected to form one contour, the associated contour numbers become the same because one is integrated with the other.

G. Embodiment In an embodiment of the present invention, an internal bus 41 as shown in FIG.
A contour extraction section 42, a contour analysis section 43, and an internal memory 44 serving as a table storage section are connected to the contour extraction section 42, a contour analysis section 43, and an internal memory 44 serving as a table storage section. Furthermore, the internal bus 4I is connected to the main bus 48 via a bus interface 45, and the information obtained by the contour detection device 4 is thereby provided to external equipment.

Next, a specific example of the command sequence generated by the contour extraction section 42 will be described. Figures 10 and 11 each have 2 pixels x
10 is a diagram showing a relationship between a black and white arrangement pattern of pixel data of two pixels and a connection relationship of contour elements to this pixel data; FIG. 10 corresponds to the case of 8-connection, and FIG. 11 corresponds to the case of 4-connection.

In these figures, the four vertically arranged windows at the left end are pixel data of 2 pixels x 2 pixels (d(, -c
L), where Ill and IOJ stand correspond to black pixels and white pixels, respectively. In addition, as shown in Fig. 13, the four windows arranged horizontally at the top end indicate the presence or absence of a front-connected contour element at the X coordinate Xn-+ of the pixel data, and the X coordinate Xn. The two frames on the bottom left and right indicate the presence or absence of a backward connection contour element at the X coordinate Xn-1 of pixel data, and the presence or absence of a backward connection contour element at the X coordinate Xn of pixel data. These are flags, and rN and rOJ mean connected and unconnected, respectively. For example, the connection flag in the pixel area surrounded by the large frame in FIG. Only the top right frame, such as the fifth one from the left in the connection flag column, is represented by the rN window.

In Figure 1O, Figure 1, Figure 1+, the intersection of the pixel data and connection flag terms is blank, which means that the outline analysis unit 43 processes such combinations of pixel data and connection flags. This means that there is no need to do this. When a combination is marked with a circle, it is necessary to process it in the contour analysis section 43, and the connection/pattern code corresponding to that combination is sent to the contour extraction section 4. Occurs at. A combination marked with a cross indicates that such a combination does not exist.

For combinations marked with a △, a connection/pattern code corresponding to the combination is generated only when encoding the run range. In Figures 6 and 7, the contour elements are drawn without considering the direction in which they occur (direction of the vector), but in reality the contour elements are drawn along the outer edge of the object (or black image area). It is caused to occur in a clockwise direction, and the establishment relationship diagrams shown in Fig. 1θ and Fig. 11 are created in correspondence with this manner of generation.

In addition to the connection/pattern code obtained in this manner, the command string includes a read ready code, a coordinate code, etc., and an example thereof is shown in FIG. 14. A1 in the figure is a read ready code, which invalidates the command sequence when the combination of pixel data and connection flag corresponds to ×, or × and Δ in FIGS. 10 and 11. A is the X coordinate of pixel data,
A3°A4 is a code indicating black and white of two pixels arranged on the left and right sides of the lower side of the pixel data, and when performing run length conversion, A3. A4 size is required. A5 is EOP (ENDOF PAG) indicating the end of one page (all lines).
E) code, A8 is EOR (E
ND OF' ROW) code, and A7 is the connection/pattern code.

Next, the contour extraction section 4. A specific example of the configuration will be described with reference to FIG.

Pixel data is input to the pixel data latch 101 from the signal line 5 and a line memory 105, which will be described later. This latch converts the input data into data d of 2 pixels x 2 pixels, that is, 4 pixels adjacent to each other, as shown in FIG. -fetch and latch d3.

Address generation circuit 108 generates X and Y coordinates in accordance with the progress of the raster scan shown in FIG. This circuit stores the generated coordinates in a line memory 105, which will be described later.
, peripheral determination circuit 109, and front flag memory 106
It is also sent to the contour analysis unit 43 via the signal line 8 as part of the command string.

The line memory 105 stores the Y coordinate which is one smaller than the Y coordinate generated by the address generation circuit 108, which is the pixel data d2 latched by the pixel data latch +01. Pixel data at the Y coordinate of d3 is fetched from the output of pixel data latch +01 and stored sequentially.

The front flag memory 106 has the same number of addresses as the number of X coordinates (for example, when the number of X coordinates is 512, the number of addresses in this memory is also 512), and if the front end of a contour element is at a certain pixel in the pixel data, When connected and the contour element is not connected to other contour elements, data of logical rlJ is written to the address corresponding to the X coordinate of the pixel.

On the other hand, the rear flag memory 107 also has the same number of addresses as the coordinates, but when the rear end of a contour element is connected to a certain pixel and that contour element is not connected to another contour element, Logic "1" data is written to the address corresponding to the X coordinate of the pixel.

The connection flag latch 102 has a forward flag memory 106,
Output data from the rear flag memory 107 and a connection flag change circuit +04, which will be described later, is held as data indicating the connection state of contour pixels.

The peripheral determination circuit 109 selects four pixels d to be processed based on the X and Y coordinates generated by the address generation circuit 108. -Determine whether d3 extends beyond the boundaries of the screen. If the pixel to be processed protrudes from the periphery of the screen, a predetermined signal is output to the pixel data latch 101 and the connection flag latch 102. When these latches receive this signal, the pixels (19-) that protrude from the boundaries of the screen are forcibly set as white pixels (background pixels).

The command generation circuit 103 generates a predetermined command to the contour analysis section 43 for contour tracing based on the four pixel data output from the pixel data latch 101 and the flag data output from the connection flag latch 102. At this time, the command generation circuit 103 sends a read ready signal indicating whether or not processing needs to be performed to the contour analysis unit 43 via the signal line 6 and the connection/pattern code via the signal line 7.

The connection flag change circuit 104 changes the connection state of the pixels after the contour analysis unit 42 executes the process according to the above command, so the connection flag after the process is changed from the output data of the pixel data latch 101 and the connection flag latch 102. The forward flag memo January 06 and backward flag memo January 07 are output to the connected flag latch 102.

Next, the operation of the circuit shown in FIG. 15 will be explained. The address generation circuit 108 generates and outputs X and Y addresses corresponding to the most recently sampled pixel data input from the signal line 5 as the raster scan progresses.

When the pixel data sampled by raster scan is manually input from the signal line 5, the pixel data latch 101 sequentially extracts the pixel data along with the pixel data from the line memo January 05, and generates two pixels as shown in FIG. ×2 pixels, that is, 1. ) Data d of four adjacent pixels. ~
Play d3.

Line memo! In month 05, the pixel data d1 output by the pixel data latch 101 is fetched to obtain the pixel data of the previous row, that is, the pixel data d whose Y address is currently input from the signal line 5.

One row of pixel data that is one row smaller than the Y address of is stored. Then, pixel data d is transmitted from the signal line 5. ,d+
are sequentially input to the pixel data latch 101, the line memory 105 generates pixel data d3. based on the address data "1" output from the address generation circuit +08. d3
are sequentially output to the same latch. As a result, the pixel data latch 101 receives four adjacent pixel data d. -d3 can be latched.

The connection flag changing circuit 104 converts the pixel data do-d
3 and the output data of the connection flag latch 102,
Generates four connection flag data.

Of the four pieces of data, two are forward connection flag data corresponding to the upper two frames of the connection flag shown in FIG. 13, and the other two are backward connection flag data corresponding to the lower two frames.

Connection flag data and its generation will be explained in detail using FIG. 16. For example, there are two images A on screen P,
B is shown, and these images are each composed of pixels marked with a circle. In the figure, the four images surrounded by thick lines are the pixels currently targeted for contour tracking processing.

On the other hand, R shown on the screen P represents forward connection flag data of each X coordinate, and T represents backward connection flag data of each X coordinate. Each piece of data is drawn in the order of coordinates, and the right side has a larger X coordinate. A blank value indicates that the value of the flag data is "0", and a value of 1 indicates that the value is "11".

Specifically, since the rear end of the outline element Ca is connected to the pixel el, the rear connection flag data Tl of the X coordinate of this pixel is Ill. Conversely, since the front end of the contour element cb is connected to the pixel e2, the forward connection flag data R2 at its X coordinate is "1". Similarly, the backward connection flag data T4 corresponding to pixel e3 is rlJ, and the backward connection flag data R4 corresponding to pixel e4
It is also rlJ. All other flag data are "
0".

These forward and backward connection flag data are written to predetermined addresses corresponding to the X coordinates of the forward flag memory 106 and the backward flag memory 107, respectively, by the connection flag change circuit 104 as described later.

When the four pixels surrounded by thick lines in FIG. 16 are the targets of processing, the front flag memory 106 and the rear flag memory 107 respectively store connection flag data R2, Output T2. On the other hand, the connection flag change circuit 104 outputs connection flag data R3, T3 corresponding to the X coordinate of the processing target pixel on the right side.

Connection flag latch 102 latches these and outputs them to command generation circuit 103 and connection flag change circuit 104.

The connection flag changing circuit 104 inputs the 4-bit connection flag data and the pixel data d from the pixel data latch 101.
. -d3 is accepted and the flag data after contour element tracking processing is obtained. That is, as shown in FIG. 17, the next contour element Cc is connected to the contour element cb in the pixel e2 through the tracking process, so the connection flag changing circuit 104 sets the forward connection flag data R2 to 10''. , the forward connection flag data R3 is set to "1". The rear connection flag data is not changed because the rear end of the contour element continues to be in a state where it does not exist independently.

The connection flag change circuit 104 stores the flag data r(2, T2 after the change process in predetermined addresses of the front flag memory 106 and the rear flag memory 107, and stores the flag data R3, T3 after the change process in the connection flag latch 10.
2 and latches it in preparation for the next process.

Then, the command generation circuit 103 receives the pixel data d from the pixel data latch 101. -d3 and the 4-bit flag data from the connection flag latch 102, a connection/pattern code is generated, and the lower two data d of the 2 pixels x 2 pixels pixel data. +dl is also output, and these codes are given to the contour analysis section 43 via the signal line 7.

Furthermore, the command generation circuit 103 is a read ready command.
'- code is output to the signal line 6 and, for example, when run-length conversion is not performed, and the connection/pattern code corresponds to the circle mark in Figures 1θ and 11, the read ready code is set to ``I''. If it corresponds to a △ mark or an X mark, it is set as "0". Additionally, the peripheral determination circuit 109 is sent via the signal line 9 to indicate the end of one page.
A P signal and a FOR signal indicating the end of one line are input, and as a result, an EOP code and an EO signal are sent to signal line 6 from here.
R code is output. In this way, the signal line 6 is supplied with an EOP code and a FOR code as well as a coordinate code indicating the X coordinate of the pixel data from the address generation circuit 108, and these codes are supplied to the contour analysis section 43.

In the above, as in the above embodiment, FIG.

Generating a read ready code according to the combination shown in FIG. 1'1 has the advantage that isolated pixels can be removed as noise. In other words, there are four types of pixel data patterns generated for an isolated pixel, as shown in Figure 17 (a) to (d), but in this case, there is no connection of contour elements to this pixel, so the following This is because the protrusion ready code is "0" and therefore no processing is being performed in the contour analysis section 43.

However, when performing run-length conversion, the read ready code becomes rlJ for the patterns shown in FIGS.

Here, the processing performed by the contour analysis section 43 is shown in FIGS. 19 to 2.
This will be explained with reference to FIG. First, as shown in Figure 19, after setting the Y address to O, a command string is fetched, and if an EOP instruction is included in this command string, the process is terminated, and if there is no instruction, a FOR is executed. Determine whether or not the instructions have been given. If a FOR instruction is given, the Y address is added by one and the command string is fetched; if a FOR instruction is not given, each table stored in the internal memory 43 (Figs. 3 to 5) is read. Reference).

The flow of updating each table is as shown in FIG. 20, and steps ST to ST3 in the figure are as follows.

ST, . . . It is determined whether a single contour element has newly occurred.

ST2: When a contour element is generated, it is determined whether or not it is connected to an already existing contour element.

ST3...The ends of the two contour elements that have already occurred are 2
It is determined whether or not it exists in the pixel×2 pixel image data.

Next, to describe the contents of processes 1 to 3 in FIG. 20, in process 1, steps ST to S are performed as shown in FIG.
T is executed. Each step ST + to ST is as follows.

S T +...A new contour element number Ci and contour number Sj are secured in the contour element table shown in FIG. 3 and the contour management table shown in FIG. 4.

ST2...Enter the applicable information in the Ci-th direction and coordinate column of the contour element table, enter N0NE (code indicating that there is no applicable item) in both the forward connection and backward connection columns of the connection element number, and enter the belonging contour. Write Si in each number column.

ST3...Write Ci in both the SI-th leading edge contour element number and end contour element number columns of the contour management table.

ST, . . . Write Ci in the corresponding columns of the forward connection and backward connection of the contour connection table shown in FIG. 5, respectively.

In process 2, as shown in FIG. 22, step ST is performed.

~S Te is executed. Each step ST, ~STs
is as follows.

ST+...A new contour element number Ci is secured in the contour element table.

ST2: Obtain the contour element number Cj of the connection destination from the corresponding column of the contour connection table, and rewrite the column to N0NE.

S13: Ci is written in the corresponding column of the Cj-th forward connection and backward connection of the contour element table, and the contour number Sk to which Cj belongs is determined from the column of belonging contour number.

S T 4... C4th direction of the contour element table,
Write the applicable items in the coordinate column, Cj in the forward connection and backward connection columns, N0NE in the other column, and Sk゛ in the belonging contour number column.

ST5: Rewrite the corresponding one of the Sk-th tip contour element number and end contour element number columns of the contour management table C11.

ST,...Write Ci in the corresponding column of the contour connection table.

In process 3, as shown in FIG.
Te is executed. Each step ST to STo is as follows.

ST, ... Obtain the two contour elements Ci and Cj to be connected from the corresponding column of the contour connection table, and set the column to N0.
Rewrite to NE.

S T 2... Write Cj in the applicable one of the Ci-th forward connection and backward connection columns of the contour element table, and write the contour number S to which Ci belongs from the belonging contour number column.
Find k.

S T 3...Writes Ci in the appropriate one of the Cj-th forward connection and backward connection columns of the contour element table, and finds the contour number Si2 to which Cj belongs from the column of belonging contour number.

Sr1... Determines whether Sk and SQ are the same number.

STs: Obtain the contour element number Cm of the Sk-th tip contour element number and the end contour element number that are not subject to connection in the contour management table, and rewrite each Sk-th column to N0NE.

STo: Of the Sa-th tip contour element number and the end contour element number of the contour management table, the column on the end side to be connected is rewritten to Cm.

FIG. 24 is a diagram showing the relationship between the above-mentioned processes 1 to 3 and the extraction position of 2 pixels x 2 pixels of pixel data. In the figure, the numbers are the numbers of contour elements, the dotted rectangles are pixel data, and the black dots are Each black pixel is shown. Processing of the command string generated for pixel data D1 corresponds to processing I, and pixel data D2
The processing of the command string generated for this corresponds to processing 2. Also, pixel data D3. The command sequence generated for D4 corresponds to the case where Sk and SI2 are equal and different in process 3, respectively.

=35-H0 Effects of the Invention According to the present invention, the arrangement state of the outline elements can be determined by knowing the connection relationship between pixels and outline elements related to 2 pixel x 2 pixel pixel data, and the black and white arrangement pattern of the pixel data. Since the connection relationship can be created based on the pixel data taken out l line before, image memory can be saved significantly compared to the conventional method of storing image data for one screen. be able to. Here, line memory has a general resolution of 16 pixels and /+yt, and even AO size is about 19,000 bits in the long direction, and if it is a few kilobytes at most, it can cover from A4 to AO size. By having memory, it is possible to realize a hardware circuit that is not affected by image size or resolution.

In addition, since processing is performed in units of I-line scanning time, contours can be extracted in approximately the same amount of time as the input time for one screen (maximum delay time of one line), resulting in significantly faster processing times than conventional methods. became possible.

Furthermore, based on the command string from the contour extraction unit, a table is created in which the coordinates of each contour element, connection relationships with other contour elements, etc. are described, and a table in which contour elements located at the front and rear ends of the contour are described, As a result, data strings that have meaning as outline elements as lines or figures are obtained, so that outlines can be easily extracted in series units (for each closed line forming the outline).

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the hardware configuration of the present invention.
FIG. 2 is an explanatory diagram showing the state of raster scanning, FIG. 3 is an explanatory diagram showing the contour element table, FIG. 4 is an explanatory diagram showing the contour management table, FIG. 5 is an explanatory diagram showing the contour connection table, Figure 6 (a). (b) is an explanatory diagram showing the relationship between pixel data and contour elements, FIG. 7 is an explanatory diagram showing the connection state between contour elements, FIG. 8 is an explanatory diagram showing the direction of contour elements, and FIG. is a configuration diagram showing the hardware configuration of the present invention, FIGS. 10 and 11 are explanatory diagrams showing the established relationship between pixel data and connection relationships, FIG. 12 is an explanatory diagram showing pixel data, and FIG. 13 is an explanatory diagram showing connections. An explanatory diagram showing flags, FIG. 14 is an explanatory diagram showing a command string,
Figure 15 is a circuit diagram showing the contour extraction section, Figure 16 and Figure 1.
7 is an explanatory diagram of connection flag data, FIG. 18 is a pattern diagram showing a pattern of isolated pixels, FIG. 19 is a flowchart showing the overall processing of the contour analysis section, FIG. 20 is a flowchart showing table updating processing, and FIG. 21 to 23 are flowcharts showing processes 1 to 3, respectively, FIG. 24 is an explanatory diagram showing the relationship between table updating processing and the position of pixel data, and FIG. 25 is an explanatory diagram showing a conventional contour pixel extraction mode. It is. ■、4. ...Contour extraction section, 2.43・Contour analysis section, 3
...Table storage section, 4...Contour detection device, 44...
・Internal memory. Fig. 1 Configuration diagram of the present invention 1 - - Contour extraction section 2 - Contour analysis section 3 - Table storage section Fig. 2 Explanation of raster scan = 40 - Fig. 3 Explanation of contour element table Explanation of contour management table Figure contour number Top contour element number End contour element number 5
oCo C+o. SI C200C300 Figure 16: Explanation diagram of connection flag data Figure 17: Explanation diagram of connection flag data Figure 18: Illustration diagram of isolated pixel pattern (a) (b) (c)
(d) Fig. 20: Flowchart of update processing Fig. 21: Fig. 22: Flowchart of processing 1 Fig. 23: Flowchart of processing 2 Fig. 24: Flowchart of processing 3

Claims (1)

[Claims] (1) In a device that detects the contour corresponding to the boundary between black and white based on binary pixel data corresponding to black and white obtained by raster scanning the subject, pixel data of 2 pixels x 2 pixels horizontally and vertically is converted into a scan line. The connection relationship between the contour element corresponding to the vector connecting two adjacent black pixels and the pixel related to the pixel data is calculated as 1.
an outline extraction unit that creates and outputs a command string based on pixel data extracted before a line, and that also includes information on the connection relationship and information on a black and white arrangement pattern of the pixel data; and the outline element. A unique code is attached to each contour consisting of a group of contour elements, and each contour element is connected to its coordinates and direction, the code of the contour to which the contour element belongs, and the front and rear of the contour element. A contour element table for recording the codes of contour elements located at the tip and end of each contour, a contour management table for recording the codes of the contour elements located at the tip and end of each contour, and the X coordinates aligned in the raster scan direction a table storage unit for storing a contour connection table for describing the code of the terminal connection contour element where the front end or the rear end is located and the distinction between the front and rear ends of the terminal connection end of the contour element in correspondence; Contour analysis that updates the description of each table in the table storage unit based on the command string from the contour extraction unit, and refers to the contour connection table to update the code of the other contour elements in the contour element table. 1. A contour detection device comprising: a.