JPH01273185A - Contour detector - Google Patents

Abstract

PURPOSE:To reduce the capacity of a picture memory by extracting a point which becomes maximum from the viewpoint of a starting point, from a contour element table and a contour control table and storing an outline vector extracted the point which becomes the maximum distance between two extracted continuous points, into an external storage device. CONSTITUTION:A contour analyzing part 2 is composed of a macro processing part 31 to extract a point which becomes maximum viewed from the starting point out of respective points to constitute one contour picture element series with original picture data, a contour element table and a contour control table edited by an original picture editing part 42 and a micro processing part 32 to extract some from the relation with the threshold to set a point which becomes the maximum distance between two continuous points extracted by the processing and describes the contour vector of the point extracted by the processing into a contour vector series table 33 and stores the contour vector into an external storage device 34. Thus, the capacity of the picture memory can be reduced.

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.

B0 Summary of the Invention The present invention provides 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. Sequentially, based on the pixel data extracted before line 1, find the connection relationship between contour pixels in the raster scan Y direction, create a command string containing this relationship and each piece of information about the pixel data arrangement pattern, The switching code between white pixels and black pixels on the line is included in the contour element and extracted, and the starting point coordinates and length of the black run are tabulated as image data from this switching code and its XY position drift to obtain the original image. Based on this original image, a table is created in which contour elements are organized into contour vector series, and the created contour vectors are stored in an external storage device such as an optical disk, thereby reducing the image memory capacity, hardware configuration, and processing time. is not affected by image size or resolution, and further allows easy extraction of contours, and
Compared to handling image information as a set of white pixels and black pixels, the amount of information and processing time processed by each part is significantly reduced, and the amount of information stored in external storage is significantly increased because the information is compressed. It is something.

C0 Conventional technology When processing patterns such as characters and figures, for example, convert 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. 32. 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, from this memory M, a point, for example, point P, which is the starting point of the contour of T to be detected is searched.

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

D1 Problems to be Solved by the Invention As described above, the conventional contour pixel extraction method requires a dedicated memory for storing one screen's worth of binary image data. 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, since the image memory increases in proportion to the vertical and horizontal sizes of the input image, a configuration that takes into account the addition of a memory board may be necessary in some cases.

For example, an image memory for AO size requires 16 times the capacity than an A4 size image memory, and even when an A4 size memory board is configured with one, AO size requires 16 times more capacity than an A4 size image memory. is necessary.

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. In addition, the amount of information and processing time processed by each section are significantly reduced compared to handling image information as a set of white pixels and black pixels.

The object of the present invention is to provide a contour detection device.

Means for Solving Problem E1 FIG. 1 is a diagram showing the configuration of the present invention, and l is a contour extraction section. As shown in Fig. 2, this contour extraction unit 1 takes in binarized pixel data corresponding to black and white obtained by raster scanning the subject, and converts the pixel data of vertical + 1!2 pixels x 2 pixels into the scan line. Based on this pixel data, a command sequence for contour detection is created, and the switching code between white pixels and black pixels on the line is included in the contour element and extracted, and this switching code and its X
The starting point coordinates and length of the black run from the Y coordinate are written as image data in the run length vector series table 41, and this image data is edited as an original image by the original image editing section 42. The command string created for contour detection is output to the contour analysis section 2 at the subsequent stage. The contour analysis section 2 analyzes the contour element table in the table storage section 3 based on the command string,
Update the descriptions in the contour management table and contour connection table. In addition, the contour analysis section 2 uses the original image data edited by the original image editing section 42, the contour element table, and the contour management table to find the maximum point among the points constituting one contour pixel series when viewed from the starting point. A macroscopic processing unit 31 for extracting;
A microscopic processing unit 32 that extracts several points based on the relationship with a set threshold value of the point that is the maximum distance between two consecutive points extracted by this process, and the outline of the points extracted by this process. The vector is written in the contour vector series table 33, and this contour vector is stored in the external storage device 34.

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 contour vector series table is used to record the code of the starting point coordinates for each contour vector series, as shown in FIG.

The command string output from the F3 effect 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 arrangement pattern of the pixel data. A connection/pattern code including information on the pixel data and a coordinate code indicating the X coordinate of the pixel data are combined.

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-1 immediately before the coordinate is connected. Note that in FIG. 6, frames with ◯ marks indicate black pixels, and frames without ◯ marks indicate white pixels.

For example, if we focus on the broad frame in Figure 6(a), the connection/pattern code in this case includes the above-mentioned connection information and the black and white array pattern information within the thick frame, and the command string is as follows:
This connection/pattern code is a combination of the coordinate code indicating the X coordinate of the pixel P1. Note that this coordinate code can 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 of Kintetsu 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 C4, Ci is written in the rear connection side of the column of the contour element Cj, and Ci is written in the rear connection column of 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 Ci to Cj.
At the same time, regarding the X coordinate of the pixel data in the contour connection table, the forward connection column of the last connected contour element number is updated from Ci to Cj. By the way, in actual processing, the elements to be connected to the contour element Ci are clarified by the contour connection table, so the C on the front connection side related to the contour element number Ci column of the contour element table
The description of j is made with reference to the contour connection table. In the above, when two contours generated separately as the raster scan progresses are connected to form one contour, one contour is integrated with the other and the associated contour numbers become the same.

In the above process, when extracting contour elements, the switching from white pixels to black pixels and vice versa are coded, and the starting point coordinates and length of the black run are calculated from the code and the XY coordinates of the image. The data is tabulated, and the white run is treated as a part where no data exists for the black run, and no processing is performed for data storage or image reproduction. after that,! Among the points constituting the contour pixel series, the point that is the maximum when viewed from the starting point is extracted, and then the point that is the maximum distance between the two consecutive extracted points is extracted. The contour vectors extracted in this way are stored in a table.

G. Embodiment In an embodiment of the present invention, as shown in FIG.
Contour extraction section 4ts Contour analysis section 4. and an internal memory 44 serving as a table storage unit, and information is received and passed between each unit via an internal bus 4I. is connected to a main bus 48 via a bus interface 45, thereby providing information obtained by the contour detection device 4 to external equipment.

In FIG. 9, 11 is a main control section, 12 is a main memory, 13 is an original image editing section, 14 is a binary image input processing section,
15 is a binary image input device such as an image scanner, and 16 is an optical disk (CD-ROM) serving as an external storage device.
) is a writing device.

In the embodiment described above, drawings and documents to be written to the CD-ROM writing device 16 are input from the binary image input device 15 to the binary image input processing section 14 . The binary image input processing unit 14 includes a multiplexer and outputs the binary image to the binary image input device 1.
It is possible to input from both the 5 side and the main bus 46 side. The input binary image is sent to the contour detection device 4, and the contour detection section 4. Detect the contour at
Send it to the contour analysis section 43 as a contour command.

The contour analysis unit 43 calculates the run length and the contour command based on the contour command.
The processing result is converted into a vector series and transferred to the main memory 12. The run-length vector series is displayed and corrected in the original image editing section 13, and becomes an original image to be written to the CD-ROM writing device 13. The edited original image is sent from the main bus 48 to the binary image input processing section 14 and further sent to the contour detection device 4.

In the contour detection device 4, the contour detection section 4! The contour is detected at , and sent to the contour analysis section 43 as a contour command. This contour analysis section 4. converts the contour vector into a series based on the contour command and transfers the processing result to the main memory 12. The contour vector series is transferred from the main memory 12 to the CD-ROM writing device side by the CD-ROM writing device 13, and a CD-ROM (optical disc) is created. Note that the operations of each device and each processing section are managed by the main control section 11. Further, the above processing process is shown in a flowchart as shown in FIG. 27.

Next, the contour extraction section 4. A specific example of a command sequence generated from the following will be described. FIG. 1O and FIG. 11 are diagrams each showing the relationship between the black and white arrangement pattern of pixel data of 2 pixels x 2 pixels and the connection relationship of contour elements to this pixel data, and FIG. FIG. 11 corresponds to the case of four connections. In these figures, the four vertically arranged windows at the left end show pixel data (dn~di) of 2 pixels x 2 pixels as shown in Figure 12, and the parts where rlJ and rOJ stand are black pixels and white pixels, respectively. Corresponds to a pixel. In addition, as shown in FIG. 13, in the four-panel window arranged horizontally at the upper end, the upper left and right two frames indicate the presence or absence of the contour element of the forward connection at the X coordinate Xn-1 of the pixel data, and the forward connection at the X coordinate x7, respectively. The two frames on the bottom left and right are connection flags that indicate the presence or absence of a backwardly connected contour element at the X coordinate Xn-1 of the pixel data, and the presence or absence of a backwardly connected contour element at the X coordinate xn, respectively. Yes, rlJ and rOJ mean connected and not connected, respectively. For example, Figure 6 (a)
The connection flag in the pixel area surrounded by the large frame is (x
Since the front end of the outline element is connected to the relevant pixel area at the coordinate position of n, Yn-1), only the top right frame is connected to the "l" frame, as shown in the fifth from the left in the connection flag column in Figure 1O. represented by a window.

In FIGS. 10 and 11, 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 generated in a clockwise direction, and the establishment relationship diagrams shown in FIGS. 1O and 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. In the figure, A1 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 Figures 1O and 11. A is the X coordinate of pixel data,
As.

A4 is a code indicating the black and white of two pixels arranged on the left and right sides of the lower side of the pixel data, and A3+A is required when performing run length conversion. A5 is EOI' (ENDOF PAGE) indicating the end of one page (all lines).
) code, All is EOrt indicating the end of l line
(END OF ROW) code, A7 is the connection/pattern code.

Next, a specific example of the configuration of the contour extraction section 42 will be explained with reference to FIG. 15.

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 the line memory +05, 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, that is, the Y coordinate of the pixel data dt, d3 latched by the pixel data latch 101.
Pixel data of coordinates is taken in from the output of the pixel data latch 101 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 5I2), 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 any other contour element, data of logic "1" 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, Logical rlJ data is written to the address corresponding to the X coordinate of the pixel.

The connection flag latch 102 is the front flag memory! 06,
Output data from the rear flag memory 107 and a connection flag change circuit 104, 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 protrudes from 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 lot and the connection flag latch 102. When these latches receive this signal, pixels that protrude from the boundaries of the screen are forced to become white pixels (background pixels).

The command generation circuit 103 generates a predetermined command to the contour analysis unit 43 to perform contour tracking 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 changing circuit 104 changes the connection state of the pixels after the contour analysis unit 4° executes the process according to the above command, so the connection flag after the process is changed to the output data of the pixel data latch 101 and the connection flag latch 102. The forward flag memory 106 and the backward flag memory 1 are calculated based on
07 and the connection 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 manually input from the signal line 5 as the raster scan progresses.

When pixel data sampled by raster scanning is input from the signal line 5, the pixel data latch 101 sequentially receives them together with the pixel data from the line memory 105, and collects the pixel data as shown in FIG. Data d0 to d3 of pixels, that is, four pixels adjacent to each other, are latched.

The line memory 105 captures the pixel data d output by the pixel data latch 101 to generate the pixel data of the previous row, that is, the row whose Y address is one smaller than the Y address of the pixel data d0 currently input from the signal line 5. Stores one row of pixel data. And signal line 5
pixel data d. , d, are sequentially input to the pixel data latch 101, the line memory 105 sequentially outputs pixel data dt, d3 to the same latch based on the address data output from the address generation circuit 108. Thereby, the pixel data latch 101 can latch four adjacent pixel data d0 to d.

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 written with ■ indicates that the value is "1".

Specifically, since the rear end of the contour element Ca is connected to the pixel e-1, the rear connection flag data Tl of the X coordinate of this pixel is rN. 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 Nj. Similarly, backward connection flag data T4 corresponding to pixel e3 is r
lJ, the forward connection flag data R4 corresponding to pixel e4 is also rlJ. Other flag data are all 10 because no outline element is connected to the corresponding pixel.
”.

These forward and backward connection flag data are written to predetermined addresses corresponding to the X coordinates of the forward flag memory 106 and backward flag memory +07, 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 changing circuit +04 outputs connection flag data R3, T3 corresponding to the X coordinate of the pixel to be processed 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.
. -d is taken, 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 change circuit 104 sets the forward connection flag data R2 to "0". and forward connection flag data R3 is set to rlJ. 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 R2, T2 after the change process in the 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 102.
It is output to and latched in preparation for the next processing.

Then, the command generation circuit 103 generates a connection/pattern code based on the pixel data d0 to d3 from the pixel data latch +01 and the 4-bit flag data from the connection flag latch 102, and generates a 2 pixel x 2 pixel pixel. The lower two data d. , dl are also output, and these codes are given to the contour analysis section 43 via the signal line 7.

Furthermore, the command generation circuit 103 outputs a read ready code to the signal line 6. For example, if run length conversion is not performed, the connection/pattern code is set to ○ in Figures 1O and 11.
When it corresponds to a mark, the read ready code is set to rlJ, and when it corresponds to a △ mark or an X mark, it is set to "0". Further, an EOP signal indicating the end of one page and a FOR signal indicating the end of one line are input to the peripheral determination circuit 109 through the signal line 9, and as a result, an EOP code and an EOR code are outputted from there to the signal line 6. In this way, the address generation circuit 10 is connected to the signal line 6.
E along with the coordinate code indicating the X coordinate of the pixel data from B.
An OP code and an EOR code are given, and these codes are given to the contour analysis section 43.

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

Generating read ready codes according to the combinations shown in FIG. 11 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 FIGS. This is because the 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 NJ for the patterns shown in FIGS. 18A and 18B, but this has nothing to do with the contour tracking process.

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 0, a command string is fetched, and if the EOP instruction is included in this command string, the process is terminated, and if there is no instruction, the FOR 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. and second
(see Figure 5).

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

S T + . . . It is determined whether or not a single contour element has newly occurred.

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

ST3: It is determined whether or not the edges of the two contour elements that have already occurred exist in the 2 pixel x 2 pixel image data.

Next, to describe the contents of processes 1 to 3 in FIG. 20, in process 1, as shown in FIG. 21, step 5TI-9
T is executed. Each step ST.

~ST4 is as follows.

ST, . . . new contour element numbers Ci and contour numbers Si are secured in the contour element table shown in FIG. 3 and the contour management table shown in FIG. 4.

S T t...Ci-th direction of the contour element table,
Write the applicable item in the coordinate column, N0NE (a code indicating that there is no applicable item) in both the front connection and rear connection of the connection element number, and St in the belonging contour number column.

S T 3...Write Ci in both openings of the Si-th tip contour element number and the end contour element number of the contour management table.

ST4...Write Ct in the corresponding columns of the forward connection and backward connection of the contour connection table shown in FIG. 5, respectively.

In process 2, steps STl to ST are performed as shown in FIG.
, is executed. Each step ST, -5T@ is as follows.

ST1: A new contour element number Ci is secured in the contour element table.

S'rt: Obtains the contour element number Cj of the connection destination from the corresponding column of the contour connection table, and rewrites the column to N0NH.

ST3: Write Ci in the corresponding column of the Cj-th forward connection and backward connection of the contour element table, and find the contour number Sk to which Cj belongs from the column of belonging contour number.

ST4...In the Ci-th direction and coordinate column of the contour element table, set C3 in the corresponding front connection and backward connection columns, N0NE in the other column, and sH in the belonging contour number column. Write.

S T , . . . The corresponding one of the Sk-th tip contour element number and end contour element number columns of the contour management table is rewritten to Ci.

STs...Write Ci in the corresponding column of the contour connection table.

In process 3, as shown in FIG.
T6 is executed. Each step ST to ST6 is as follows.

S T +... Obtain two contour elements Ci and Cj to be connected from the corresponding column of the contour connection table, and rewrite the column to N0NE.

S T t...Writes Cj in the applicable one of the C4th front connection and rear connection double opening in the contour element table, and finds the contour number Sk to which Ci belongs from the column of belonging contour number.

STs...Ci is written in the applicable one of the Cj-th front connection and rear connection double opening in the contour element table, and the contour number S (to which Cj belongs) is written from the column of belonging contour number.
seek.

ST4...Determine whether Sk and SQ are the same number.

ST5: Obtain the contour element number Cm which is not the object of connection among the Sk-th tip contour element number and the end contour element number of the contour management table, and rewrite each Sk-th column to N0NE.

ST8: Out of the Sg-th tip contour element number and 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. The processing of the command string generated for the pixel data D1 corresponds to processing l, and the processing of the command string generated for the pixel data D,
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 Sa are equal and different in process 3, respectively.

The run range vector series processing will be described below.

FIG. 29 shows a processing code format, in which contour pixel state codes (switching codes) eQ and el are added to the conventional one. The codes e0 and e are each set to 1 bit,
White pixels are assigned logic "0" and black pixels are assigned logic "1". For example, as shown in the relationship with the raster scan shown in FIG. 30, for a line with Y coordinate Yh-+,
A contour exists at the boundary between t and X n-+ and the boundary between X and X pet, and the Y coordinate is Y.

X on the line. There are contours at the boundaries between -1 and xll and at the boundaries between X, and and “l” and “0” of el are determined.

Such codes el, e(, are the command generation circuit 103
“0.1 of data do, d+ when generating processing code by
' or 'l, 0'', and X
The coordinates are synchronized and output.

Also, since the code el+60 corresponds to the contour position,
The code e1. The processing code including eo is taken into the contour analysis section 43.

The contour analysis unit 43 uses the code el+e of the processing code.

An encoding process is performed from the and X coordinate data according to the procedure shown in FIG. 28, and the result is saved in a table as image data. This encoding process will be explained in detail below.

First, the contour analysis unit 43 reads the contour command input, which becomes the processing code and the X coordinate data, at the Y address (
Set the Y coordinate (Sl) to Y=O, and set the first line of the page of the subject. Next, read the contour command manually and import it at the ready timing (S2
), it is determined whether the signal EOP bit is "1" or "0" (S3).

In this determination, it is checked whether or not it is the end of one page of the subject image, and when EOP="1", the encoding of the page is finished.

In step S3, when EOP=“0”, it is determined whether the signal EOR bit is “l” or “O” (S4
). This judgment is made by checking whether it is the end of one line (ROW) of the image, and when FOR="l", the Y address is incremented by +1 to indicate the end of encoding of the line (S5
), the process returns to step S2 and starts extracting the contour command from the next line. In step S4, FOR
="0", a determination is made regarding the code e I + e G (S6).

This judgment is made by checking e, = "O" and Q, = "1", and if this condition is met, it is the beginning of a black run, and from the X coordinate data at this time, the black run starting point coordinate XBS of the second line is (K) is obtained (S7), and the process returns to step S4.

If the condition is not satisfied in step S6, then it is likely to be in the middle of a black run or a white run, and is at the end of the black run, and the code is e.

= "l" or -"0"(S8); if the condition is not satisfied in this check, the process is in the middle of a black run or a white run, and the process returns to step S4.

When the condition is satisfied in step S8, it is at the end point of the black run (starting point of the white run), and the coordinates XB, (K) of the end point of the black run are calculated from the X coordinate data at this time (
S9). This black run end point floor tlxa, (K) and the black run start point coordinate XBS (K
) to the length of black run L (=XB, (K)-XBS(K
)), and calculate this length data L as the black run starting point dust wxBs
(K) in the memory 44), and returns to step S4 again to repeat the process of detecting and storing the starting point coordinates and length of the black run, and repeating this process until the end of the page.

Through such processing, the starting point coordinates and lengths of black runs for each line are sequentially stored as many as the number of black runs, and this is stored as table data in the memory 44. FIG. 31 shows an image data table stored in the memory 44, in which the line number (Y coordinate), the X coordinate of the black run starting point, and its length are stored in association with each other.

Reproduction of the object from this data is realized by displaying or printing continuous black pixels for a length at each black run starting point at the XY coordinate position using a raster scan method.

Next, the contour vector series processing will be described.

Figure 2.5 shows the macroscopic processing unit 3! In this explanatory diagram, this 25th
In the figure, the contour series Po(Xo
, Yo), P+(X+, YI)-Pt(X+.

y, )-p, (xn, Yn) [where P is the starting point of contour tracing], all points Pi that satisfy the following condition 1 are extracted as straight line approximation points.

[(+'+-+≦1''+)n(t''+>l''+-+)n
(+"+≧I"th) Condition l However, itI is the square of the distance between Po and Pt (shown in equation (1)), and l"th is the square of the threshold value.

1”L= (X t X (1)+(vt-vo)”
-(t) FIG. 26 1 is an explanatory diagram of the microscopic processing unit 32. In this FIG. 26 a, contour series points P, , p, . . . PtI, Pa . From Pk to straight line approximation point Qo (=Pa) + Q++ Qt...q+(
=P+).

Q**+ (=p J),...qnc=Po) is determined by the following procedure. Two consecutive points among the currently extracted straight line approximation points (shown in Figure 26), Q l + Q
le+ (initially qo and q+ obtained by the macroscopic processing unit 31
), a point that satisfies condition 2 shown below is extracted as q, □ (including the process of changing Q III to q, 1), and the same process is repeated. If there is no point that satisfies condition 2, the same process is repeated for Q l"l + Q 142. This process is repeated until all points P are satisfied.

ldl'',.8≧-di', hl...Conditions are met, dl,...: Maximum value of each d1 dl''aax=
iax [・=, d l'J, -ko d1: line segment q
l, q, 0. Distance dlth from to each P point: d with a threshold value that changes depending on the size of the line segment qt, q□,
It is given by 1th=α・shi.

Note that α is a coefficient and is an example shown in FIG. 26C. For example, α may be tabulated as shown in FIG. 26C. Furthermore, if α is a constant such as I, 2, etc., the threshold value is simply proportional to L.

Next, how to obtain dl will be described using FIG. 26d.

1−−→ −1→ −−1→ −−→(Q+Q+++
'q+PJ)=lQtQ+*mouthIQIPJIcO8θ
J=(xmxυ(YJ Yi)+(Yh YI)(
XJ Xo where X kX 't = d X h
, Y J Y t = d Y J .

Y −Y r = d Y k, X J X l
If we set = d X J, the above formula becomes as follows.

,’,l　qshoulderbe1! . . eθ.

=(dXhXdY, ++dYhXdXa)”/ l q
tq+−+l ”−−→.

dN=lQtP,+lSI+104dlj"=1
31"sin"θJ = +7tel"131"c
os"θ.

-1-→
−〉=l Q IPJI” (d Xhx d Y
J+ d YhX d XJ)”/I Q r Q t
-11'= d XJ"d YJ'-(d XkXd
Y4"d Yhxd XJ)'/d Xh"+d Y-
Trigonometric functions and square root calculations can be omitted from the above.

H1 Effects of the Invention According to the present invention, the arrangement state of outline elements can be recognized by knowing the connection relationship between pixels and outline elements related to 2 pixels x 2 pixels pixel data, and the black and white arrangement pattern of the pixel data. Since the above-mentioned connection relationship can be created based on the pixel data taken out before the I line, it is possible to significantly save image memory compared to the conventional method of storing image data for one screen. . Here, the line memory has a typical resolution of 16 pixels/aX.
Even O size is about 19,000 bits in the long direction, and with a few kilobytes at most, it can cover everything from A4 to AO size, and by having that much memory, it is possible to create a hardware circuit that is not affected by image size or resolution. can.

In addition, since processing is performed in units of scanning time for one line, the time is approximately equal to the input time for one screen (maximum 19
Because contours can be extracted within a 12-minute delay (delay time of 12 minutes), significantly faster processing is possible compared to the processing time of conventional methods.

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).

In addition, in the present invention, compared to handling image information as a set of white pixels and black pixels, the amount of information and processing time processed by each section are significantly reduced because it is stored as a set of outline vectors rather than a set of pixels, so information is compressed. This is to be done. Moreover, the amount of information stored in the external storage increases significantly because the information is compressed.

[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. 1 is a configuration diagram showing the hardware configuration of the present invention, FIG. 1 θ and FIG.
Fig. 2 is an explanatory diagram showing pixel data, Fig. 13 is an explanatory diagram showing connection flags, Fig. 14 is an explanatory diagram showing a command string, Fig. 15 is a circuit diagram showing an outline extraction section, and Figs. 16 and 17.
18 is a pattern diagram showing an isolated pixel pattern, FIG. 19 is a flowchart showing the overall processing of the contour analysis section, FIG. 20 is a flowchart showing table update processing, and FIG. 23 are flowcharts showing processes 1 to 3, respectively, FIG. 24 is an explanatory diagram showing the relationship between the table update process and the position of pixel data, and FIG. 25 is an explanatory diagram showing the contour vector series table.
Figure 26 a = d is an explanatory diagram of macroscopic and microscopic processing;
FIG. 27 is a flowchart describing the processing of the embodiment of the present invention in FIG. 9, FIG. 28 is a flowchart of encoding processing, FIG. 29 is a processing code format, and FIG. 30 is a diagram showing the relationship between raster scan and code el+eQ. , FIG. 31 is a code element table, and FIG. 32 is an explanatory diagram showing a conventional outline pixel extraction mode. l, 4. ...contour extraction section, 2, 4. ... Contour analysis section, 3 ... Table storage section, 4 ... Contour detection device, 4
4... Internal memory, 31... Macroscopic processing unit, 32.
. . . Microscopic processing unit, 33 . . . Contour vector sequence table, 41 . . . Run length vector sequence table, 4
2...Original image editing department. Fig. 1: Configuration diagram of the present invention Fig. 3: I! of contour element table Figure 4 Figure 5 Contour connection table Figure 6 Relationship diagram between pixel data and contour elements (a) (b) l-for 41
・Internal bus 12 ・Main memory 46
...Main bus (optical disk) Fig. 10 Diagram of the establishment of pixel data and connection relationships - Nini = ni]] Fig. 12 Fig. 13 An explanatory diagram of pixel data An explanatory diagram of connection flags An explanatory diagram of command strings No. 11 15. Circuit diagram of contour extraction unit. 16. Explanation of connection flag data. 18. Illustration of isolated pixel pattern (A). b) (c)
(d) Fig. 19: Flowchart of overall processing of the contour analysis section Fig. 20: Flowchart of update processing Fig. 21 Fig. 22: Flowchart of processing 1 Fig. 23: Flowchart of processing 2 Fig. 23: Flowchart of processing 3 Fig. 24: Update processing and pixel data Figure 25: Contour vector series table: Macroscopic and microscopic (a) (C) Explanatory diagram of 1-dimensional processing (b) P) (d) P+(X+,YS) Figure 27 Figure 29 Diagram xa showing the relationship between processing code format raster scan and codes e''+ and eo
XnJ Xn-1xn
xp XP+I
Xll! eo ('l eg
e+Figure 32 Conventional contour pixel extraction mode diagram

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.
A command string is created and output based on the pixel data extracted before the line, and also creates and outputs a command string including information on the connection relationship and information on the black and white arrangement pattern of the pixel data. a contour extraction unit that generates a switching code (e_0, e_1) between a pixel and a black pixel, and assigns a unique code to each of the contour elements and a contour made up of a group of these contour elements, and assigns a unique code to each contour element. A contour element table for recording the coordinates and directions, the code of the contour to which the contour element belongs, and the codes of other contour elements connected before and after the contour element, and a contour located at the tip and end of each contour. A contour management table for recording element codes, X coordinates aligned in the raster scan direction, codes of end-connected contour elements whose front or rear ends are located at those coordinates, and front and rear ends of the end-connected ends of the contour elements. a table storage section for storing a contour connection table for describing the contours in correspondence with each other; and updating the description of each table in the table storage section based on the command string from the contour extraction The codes of the other contour elements in the element table are updated by referring to the contour connection table, and the start and end point coordinates of the black run are calculated from the switching code and the coordinates on the line, and the start point coordinates of the black run are determined. and the length as image data to obtain the original image, and from the contour element table and the contour management table, extract the maximum point from the starting point among the points constituting one contour pixel series, and A contour analysis section that stores in a storage section a contour vector obtained by extracting a point that is the maximum distance between two consecutive points, and an external storage device that transfers and stores the contour vector stored by this contour analysis section. A contour detection device comprising: