JPH01277976A - Image processor - Google Patents

Abstract

PURPOSE:To attain the vectorization with fidelity of an original image and to facilitate an operation by recognizing the arranging state of a contour element from the connection relation of an image element and the contour element relating to image element data of 2 image elements X 2 image elements and the black/white arranging pattern of the image element data. CONSTITUTION:A contour extraction part 1 fetches binary data corresponding to black/white by performing raster scan on an object, and takes out the image element data of 2 image elements X 2 image elements in crisscross sequentially along a scan line, and detects the contour based on the image element data, and generates a command string for runlength vectorization and one-dimensional coding, and outputs them to a contour analysis part 2. The processing part 21 of the analysis part 2 updates the description of a contour managing table and a contour connection table in a memory 31, and a processing part 22 generates runlength vector information and stores it in a memory 32, and a processing part 23 performs the vectorization of the contour consisting of a contour element group based on the contour element table, and describes a formed contour vector group on a memory 33.

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 taken out sequentially and before the line, for example, the connection relationship between contour pixels in the raster scan Y direction is determined, and a connection/pattern code containing information on this relationship and the pixel data arrangement pattern is generated. At the same time, it creates pixel array data arranged left and right in one line, and also creates a table in which the outline elements are series based on the connection/pattern code. The image memory capacity is
Hardware configuration and processing time are not affected by image size or resolution, it is possible to achieve vectorization that is faithful to the original image, and it is possible to easily perform single-rotation operations such as enlargement and reduction, and furthermore, it is easy to reproduce the original image. It was made 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 (human cover 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. 33. 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 the points adjacent to this point P1 and
Extract the contour pixels of.

D2 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 board, 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 contours, it is necessary to perform sequential tracking using software, which also requires The processing time will be affected in proportion to the size and resolution of the image.

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 a contributing factor.

The present invention was made to solve these problems, and achieves vectorization that is faithful to the original image without being affected by image memory capacity, hardware configuration, processing time, image size or resolution. It is an object of the present invention to provide an image processing device which can easily reproduce an original image, and can easily perform enlarging and reducing one-rotation operations, and can also easily extract contours.

Means for Solving Problem E1 FIG. 1 is a diagram showing the configuration of the present invention, where ■ 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 extracts pixel data of 2 pixels x 2 pixels along the scan line. Based on this pixel data, command sequences for contour detection, run-length vectorization, and one-dimensional encoding are created and output to the contour analysis section 2 at the subsequent stage. The contour analysis unit 2 stores data in the first memory 3. based on the command sequence. A first processing unit that updates the descriptions of the contour element table, contour management table, and contour connection table in 2. Then, based on the command string, run length vector information is created, which is a set of the starting point and length of the black run, and is stored in the second memory 3. The second processing unit 2.
Then, based on the contour element table, a contour consisting of a group of contour elements is vectorized to create contour vector details, and this contour vector group is recorded in a contour vector series table in the third memory 33. Processing unit 2. It has

Here, the contour element corresponds to a vector connecting two adjacent black pixels, and by combining these, a contour is constructed. 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 a table for recording the codes of the contour elements located at the tip and end of each contour, as shown in FIG. 4, and the contour connection table is a table for raster scanning as shown in FIG. This is for describing the coordinates arranged in the direction, the code of the terminal connected contour element whose front end or rear end exists at the coordinate, and the distinction between the front and rear ends of the terminal connected end of the contour element in correspondence.

The command string output from the F1 effect contour extraction unit l 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, a coordinate code indicating the X coordinate of the pixel data, and left and right pixel array data on the lower line of the pixel data of, for example, 2 pixels x 2 pixels. 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 becomes information that the front ends of the contour elements located at the X coordinate Xn of this pixel data are connected. In this example, the coordinates of the pixel data are the coordinates of the pixel P1 located at the lower right when facing the page. In addition, when the pixel data surrounded by the large frame in Figure (b) is imported, the information that the rear end of the contour element located at the position mx, one position before the X coordinate of this pixel data is connected. Become.

Note that in FIG. 6, frames with ◯ marks indicate black pixels, and frames without ◯ marks indicate white pixels. For example, Figure 6 (
Focusing on the general outline of b), the connection/pattern code in this case is the same as the connection information above.

The command string is a combination of this connection/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 general frame in Fig. 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, the contour element Cj is located in front of the contour element Ci, so Ci is written in the rear connection shelf in the column for the contour element Cj, and Ci is written in the front connection side in the column for 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-a.

is defined, and in the case of four connections, four directions, up, down, left and right, are defined. Then, regarding the contour number Si in the contour management table, the tip contour element number field is updated from Ci to Cj, and regarding the X coordinate of the relevant pixel data in the contour connection table, the forward connection field of the end connected contour element number is updated to Ci. Update from Cj 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 description of Cj on the front connection side related to the contour element number Ci column of the contour element table is Please refer to the 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. Further, run length vector information is created in which the starting point and length of a black run are paired based on the pixel array data of the command string and the X coordinate of the pixel data, and is stored in the second memory.

Furthermore, from among the points constituting one contour pixel series from the contour element table, a local maximum point that is the maximum when viewed from the starting point is searched, and a point on the contour that is at the maximum distance from a straight line connecting this local maximum point and the starting point is found. By repeating the same process on the straight line connecting this point and the starting point, find the point Q before the maximum distance becomes less than the threshold, and then create a vector connecting this point Q and the starting point. is extracted as a contour vector, and then a contour vector is extracted by performing similar processing using the point Q as a starting point, and information regarding the contour vector group thus obtained is loaded into the contour vector series table.

In the above, the second processing unit 2. , the start and end point coordinates of the black run and white run are further determined based on the pixel array data of the command string and the X coordinate of the pixel data, and a code word of the one-dimensional encoding method is created. A function of storing the data in the memory 33 may be provided.

G. Embodiment In an embodiment of the present invention, an internal bus 41 as shown in FIG.
Contour extraction section 4. , a contour analysis section 43 including a first processing section 43A, a second processing section 43B, and a third processing section 43C, and a contour analysis section 4. The internal bus 4 is connected to an internal memory 44 for temporarily storing data obtained in the internal bus 4, and information is exchanged between each section through the internal bus 4. The bus interface 4. It is coupled to main bus 48 via. 5 is a binary image manual processing section, through which the binary image data inputted from the binary image input device 6 is passed to the contour extraction section 4. give to This process is executed by giving an instruction to the binary image manual processing section 5 when the main control section 7 receives an input instruction from the input/output processing section 8.

A main memory 9 is used to store data obtained through processing by the contour analysis section 43.

In this embodiment, the main memory 9 also serves as the first to third memories that are the constituent elements of the present invention.

Next, outline extraction section 4. A specific example of a command sequence generated from the following will be described. Fig. 1θ and Fig. 11 each have 2 pixels x
FIG. 10 is a diagram showing the relationship between the black and white arrangement pattern of pixel data of two pixels and the connection relationship of outline elements to this pixel data; FIG. 1O 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 (do-ds) as shown in Figure 12.
), and the portions where NJ and rOJ stand correspond to black pixels and white pixels, respectively. In addition, as shown in FIG. 13, the four-panel windows arranged horizontally at the top end are divided into two windows on the left and right sides of the pixel data. 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-+ of pixel data, and the presence or absence of a backward connection contour element at the X coordinate Xn of the 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 a "!" window.

In FIGS. 10 and 11, the intersection of the pixel data and connection flag terms is blank, which means that the contour analysis unit 4. This means that there is no need to perform any processing. For combinations marked with ○, the contour analysis section 4. It is necessary to perform processing in the contour extraction section 4, and the connection/pattern code that is added to the combination is processed in 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. A 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 pixel array data, that 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.

A5 indicates the end of one page (all lines) E OP (E
ND OF PAGE) code, A is a FOR (END OF ROW) code indicating the end of the l line, and A7 is a 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 supplied to the pixel data latch 101 from the signal line 5 and a line memory 105 to be described later. This latch generates data d of 2 pixels x 2 pixels, that is, 4 pixels adjacent to each other, from these manually input data 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 l smaller than the Y coordinate generated by the address generation circuit 108, that is, the Y coordinate of the pixel data d+, da latched by the pixel data latch lot.
The pixel data of the coordinates is fetched from the output of the pixel data ludge +01 and sequentially distributed t@.

The front flag memory +06 has the same number of addresses as the number of X coordinates (for example, when the number of When connected and the contour element is not connected to other contour elements, logical IN data 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 NJ 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 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 101 and the connection flag latch 102. When these latches receive this signal, pixels that protrude from the border of the screen (□) are forced to become white pixels (background pixels).
shall be.

The command generation circuit +03 generates a predetermined command to the contour analysis section 43 for contour tracing based on the four pixel data outputted by the pixel data latch lO1 and the flag data outputted by 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.

Connection flag change circuit! In 04, after the contour analysis unit 4° performs processing according to the above command, the pixel connection state changes, so the connection flag after processing is based on the pixel data latch +01 and the output data of the connection flag latch 102. Therefore, the flag memory 106, the rear flag memory 107, and the connection flag latch! Output to 02.

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 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 takes in the pixel data d1 output by the pixel data latch 101 to obtain one row of pixel data, that is, the pixel data d whose Y address is currently input manually 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. ,dl
are sequentially input to the pixel data latch 101, the line memory 105 sequentially outputs the pixel data dt and ds 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 d6 to d3.

The connection flag changing circuit 104 converts the pixel data d6 to d
2 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 two at the bottom 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 each of these images is composed of pixels on which a circle is written. 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 field indicates that the value of the flag data is "0", and a blank field indicates that the flag data value is rlJ.

Specifically, since the rear end of the contour element Ca is connected to the pixel el, the rear connection flag data Tl of the X coordinate of this pixel is "1". 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 rlJ. Similarly, backward connection flag data T4 corresponding to pixel e3 is rlJ, and forward connection flag data R4 corresponding to pixel e4.
is also "1". 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 latches the 4-bit connection flag data and pixel data! Pixel data d from 01
0 to d3 are 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 "!". 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.

Connection flag change circuit! 04 stores the flag data R2, T2 after the above modification 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 modification process in the connection flag latch 102.
It is output to and latched in preparation for the next processing.

Then, at the command generation time Q103, the pixel data d from the pixel data latch 101. -d3 and the 4-pit 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 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, and the connection/pattern code is as shown in FIG.
When the code corresponds to the mark ○ or the mark Δ in FIG. 11, the read ready code is set to NJ. Further, an EOP signal indicating the end of one page and an EOrt 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 signal line 6 has
Along with the coordinate code indicating the X coordinate of the pixel data from the address generation circuit 108, the EOP code and EOr? The codes are given to the contour analyzer 4. given to.

In the above, FIG. 1O as in the above-mentioned embodiment.

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 performed in the contour analysis KS43.

°However, when implementing run length conversion, see Figure 18 (
In the case of patterns (a) and (b), the read day code is "1", but this has nothing to do with the contour tracking process.

Here, the processing performed by the first processing section 43A of the contour analysis section 43 will be explained with reference to FIGS. 19 to 23. 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, the internal memory 4. Each table stored in the first table storage section (see FIGS. 3 to 5 and FIG. 26) is updated.

The flow of updating each table is as shown in FIG. 20, and steps ST and -5T3 in the figure are as follows.

ST, . . . It is determined whether 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.

STs: It is determined whether or not the ends of 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, steps ST and -S are performed as shown in FIG.
T is executed. Each step ST.

~ST, is as follows.

ST, . . . new contour element numbers Ct 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 relevant information in the coordinate column, N0NE (a code indicating that there is no corresponding item) on both sides of the curved blade connection and rear connection of the connection element number, and Si in the affiliated contour number column.

STs...Ci is written on both sides of the St-th tip contour element number and end contour element number of the contour management table.

S T 4...Write Ci in the corresponding columns of the front connection and rear connection of the contour connection table shown in FIG. 5, respectively.

In process 2, as shown in FIG.
STa is executed. Each step ST, to STs is as follows.

ST, . . . New contour element number Ci is secured in the contour element table.

S T z...Determine the contour element number Cj of the connection destination from the photometry in the contour connection table, and rewrite the column to ll0NE.

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

ST,...In the Ci-th direction and coordinate column of the contour element table, enter Cj in the corresponding column of forward connection and backward connection, N0NE in the other column, and Sk in the belonging contour number column. Write each.

ST, . . . Rewrites the corresponding one of the Sk-th tip contour element number and end contour element number columns of the contour management table to Ci.

S T s...Ci in the corresponding column of the contour connection table
Write.

In process 3, as shown in FIG.
T@ is executed. Each step ST to STa is as follows.

S T +... Two contour elements Ci and Cj to be connected are obtained from the photometry of the contour connection table, and the relevant side is written as N0NE.

ST,...Insert Cj into the applicable one of both sides of the Ci-th forward connection and backward connection in the contour element table, and set the contour number Sk to which Ci belongs from the column of belonging contour number.
seek.

S T 3...Write Ci to the appropriate one of both sides of the Cj-th forward connection and backward connection in the contour element table, and find the contour number SQ to which Cj belongs from the column of belonging contour number.

ST, . . . determines whether Sk and 1 are the same number.

S T s...Find the contour element number Cm of the Skth tip contour element number and the end contour element number that are not subject to connection in the contour management table, and set each column of the Skth column to N0NE, Rewrite it to .

S T s... Of the SQth 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 sequence generated for the pixel data D corresponds to processing l, and the processing of the command string generated for the pixel data Dt
The processing of the command string generated for this corresponds to processing 2. Further, one column of columns generated for the pixel data D, ,D corresponds to the cases where Sk and S(2 are equal and different) in process 3, respectively.

Next, the processing performed by the second processing section 43B of the contour analysis section 43 will be explained. This processing includes processing for creating run-length vector information and processing for creating code words for a one-dimensional encoding method. It will be done.

First, we will discuss the process of creating run-length vector information. For example, if a pixel pattern as shown in FIG. 25 exists on the line Y 1fi-Yi,
If the X coordinates at the position of ■ are Xi and Xj, respectively, then
When pixel data of 2 pixels x 2 pixels whose coordinates are Xi is imported, A3. of the command string shown in FIG. A4 is "0" respectively.

"1", and when data of 2 pixels x 2 pixels with the X coordinate of A4 is “l” respectively
, becomes "0". Therefore, the start point and end point of the black run can be recognized, and the start point coordinates and length of the black run, which are run length vector information, can be obtained. In the example of Fig. 25, the starting point X coordinate of the black run is xi1, and the ending point X coordinate is Xj.
-1, so the length of the black run is )(j-1-Xi+1
=Xj-Xi.

A specific example of such processing will be explained with reference to FIG. 26. First, the outline extraction section 4. When reading the command string from S, set the Y address (Y coordinate) to Y=0.
l), set the first line of the page of the subject (
. Next, the command string (contour command) is read out and taken in when the ready code is rlJ (S2), and it is determined whether the signal EOP bit is "l" 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-"l", the processing of the page is ended.

In step S3, when EOP becomes "0", it is determined whether the signal EO1't bit is "l" or "0" (
S4), this judgment checks whether it is the end of one line (ROW) of the image, and when FOR-“!”, the processing of the line is finished and the Y address is incremented by +1 (S4).
5) Return to step S2 to begin extracting the command string from the next line. In step S4, F OR=
When it is “0”, the code e In e o (A 3 of the code in FIG. 14).

(corresponding to A4) is determined (S6).

This judgment is made by checking eo-“0” and el=“I”, and if this condition is met, it is the beginning of a black run, and from the X coordinate data at this time, the second black run starting point coordinates XB, ( K) is obtained (S7), and the process returns to step S4.

If the condition is not satisfied in step S6, then the position is in the middle of the black run or white run, or at the end of the black run, and the code is e.

- "l" - "0" is checked (S8), and if the condition is not satisfied in this check, it 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 coordinate XB, (K) and the black run start point coordinate XB, (K) obtained previously in step S7
Length of black run from (-XB, (K) -xa, (K)
), and use this length data L as the black run starting point coordinates X. (K
) is stored in the main memory 9 in association with S10), and the process returns to step S4 again to detect and store the starting point coordinates and length of the black run, and this process is repeated 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 main memory 9. FIG. 27 shows an image data table to be stored in the memory 4, 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.

Next, we will discuss the one-dimensional encoding process.
This is also called H encoding processing, and is a process in which a code word that encodes the length of a white run and a code word that encodes the length of a black run are sequentially arranged and stored. The first code word on the I line always starts with a white run, and a line end code is always added to the end of the I line, thereby performing line-by-line encoding.

■Since white runs and black runs appear alternately in the line, ■If the next black run on the line is BK, and the white run immediately before this black run is WK, then Wo, Bo,' WI
, B 1"', Wx, Bx"' runs are obtained. When there is a black run Bo first, there is a white run B of length O. is treated as existing. The length 12s (K) of B is the start and end point of S6, , (K)
,

In addition, the length of WK ffw (K) is the starting and ending point of WK
Let the coordinates be X, ,(K),X,. (K), it can be found as follows.

In reality, when an outline command is generated and the start and end points and length of the black run are found, the start and end points and length of the white run can be found, and processing can be performed sequentially while watching the commands being generated.

A specific example of such processing will be explained with reference to FIG. 28. First read the command string and the ready code is “1”
is captured (Sl) when the signal EOP bit becomes “
A determination is made as to whether the flag is "0" or "0" (S2). This judgment checks whether it is the end of one page of the subject image, and
When it is "1", the process (S3) of adding six consecutive line end code words defined in the MH system is performed, and the encoding of the page is finished.

Next, in step S2, when EOP="0", it is determined whether the signal FOR bit is "1" or "0" (S4). This judgment is made by checking whether it is the end of one line (ROW) of the image, and when FOR-“l”, a process of adding a line end code word (S5) is performed, and the process returns to step Sl for reading the next line. return. Step S4
, when EOR-“0”, the code is e. +e1(
A3 in Figure 14. A) is determined (S6).

This judgment is made by checking eo = "0" and el = "1". If these conditions are satisfied, it is the beginning of a black run, and from the X coordinate data at this time, the black run starting point I is on the 1st line.
Find X, , (K) (S7). Also, if the condition is not satisfied, e. - Determine “1” or “0” (S8
), if this condition is not satisfied, the process returns to step Sl.

In step S7, the black run starting point coordinates XB, (K) are determined,
When black pixels continue from this X coordinate and the condition is met in step S8, the end point XB, (K) of the black run is determined from the X coordinate data at that time, and the starting point X8.
The length of the black run &, (K) is calculated by calculating the X coordinate difference between (K) and the end point (SIO).

Next, when the black run starting point XB, (K) is determined in step S7, the black run starting point X, , (K) is the ending point XW of the white run.
, (K), and corresponds to the black run end point X8. obtained in step S9. (K) is the starting point Xw of the white run.

Corresponds to (K). From these coordinates, start point X of the white run,
, (K) and the end point Xw. Find (K) and its length &, (K) (Sll) and create a white run code word (S12)
.

Through this process, codewords are created for each line as many times as there are alternately white runs and black runs, and
Obtain facsimile transmission data.

Next, the processing performed by the third processing section 43C of the contour analysis section 43 will be explained with reference to FIGS. 29 and 30.

FIG. 29 shows a contour vector series table stored in the main memory 9.
A contour vector group, which will be described later, is described by . 29th
In the figure, the contour vector series number is a code given to each contour, and the starting point coordinates are the starting point coordinates of the contour vector.

For extraction of contour vectors, for example, each starting point P of contour elements constituting one contour is extracted. (X,.

Yo), P+ (X+, Y+) - Pt (Xt, Y+) ・
...When Pn(X,,Yn) [where Po is the starting point of contour tracing] is given, a point P8 that is the maximum from the starting point, that is, a point P8 that satisfies the following condition 1, is searched as the maximum point.

[(1"i-t≦1"+)n (1't>l"t-+
)n (1″t≧I″th)]...conditions apply, 11. is the square of the distance between Po and P (shown in equation (1)), and 1'' is the square of the threshold value.

1"1=(X+Xo)'+(Y+Yo)"
...(1) Figure 30a is the maximum point P with respect to the starting point P0,
After finding the maximum point Pt, P is the point q that is at the maximum distance from the straight line connecting the starting point P0 and the maximum point P□. −P, and find this point q and the starting point P
. Find the point q' that is at the maximum distance from the straight line connecting them, and repeat the same process in sequence. Then, when the maximum distance becomes less than the threshold value, a vector connecting the previous point Q, that is, the point Q found before the point located at the maximum distance, and the starting point P0 is extracted as a contour vector.

Figure 30 is a diagram showing how to find the point q, and if the point Q + *l shown in the figure is smaller than d1□ or the threshold value, that is, if the following condition 2 is not satisfied, then the above becomes point Q.

l d l",,, ≧d l"th l...conditions d 1. ,, : Maximum value d l'P of each d1
ax=max[..., di",...] d1: Distance from line segment q+, q+□ to each P point dlth: Line segment QI
+Qt, d 1t with a threshold value that changes depending on the magnitude of +
It is given by h-α・L.

Note that α is a coefficient and is an example shown in FIG. 30C. For example, α may be tabulated as shown in FIG. 30C. In this way, it is possible to deal with objects included in the drawing that are extremely different in size (such as connecting lines for characters). Moreover, if it is set to a constant such as α-1, 2, . . . , the threshold value becomes simply proportional to L.

Next, describe an example of how to obtain dl using FIG. 30d.

−〉−〉−1111□□ra −−−−−→(q+qt
Number 1 ° Q IP J) = IQ IQ l・
+llq IP JlcOsOJ-(Xk XI)(
YJ YI)+(Yh YI)(XJ Xi) where Xk X+=dXh, YJ Y+=dYa.

By setting Yk Y+=dYk, XJ XI"dX, +, the above equation becomes as follows.

11−−−→ Pa・l q IP, 1”cos'θJ−1−−→ −(dXhXdY, ++dYhXdXJ)”/l (1
+Q+zl 'dlj-l q+Pr1sinθ.

d I j"=171"sin'θJ=l 7
'-171 "cos J+
−−→=I Q +
P, +l' (d XkX d YJ+ d YhX
d XJ)'/l Q1q+-11'= d XJ"
d YJ'-(d XkX d Y, I"d YkXd
XJ)''/d Xk'd Yk' From the above, according to this example, trigonometric functions and square root calculations can be omitted.

1. As mentioned above, the starting point P. After extracting the contour vector connecting point Q and point Q, a new contour vector following the contour vector is obtained by performing the same process using this point Q as the starting point, and each starting point of the group of contour vectors obtained in this way is 29 is stored in the table shown in FIG.

Here, if the total length of the contour vector group is less than the threshold value, it is determined that it is noise, and data related to that vector group is removed from the contour vector series table, and if the total length exceeds the threshold value, information about the total length is determined. is created and written in the total length information table in the second table storage section as shown in FIG. 31 in correspondence with the contour vector sequence number. Such a flow is shown in FIG. 32.

H. 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 pixel data of 2 pixels x 2 pixels, and the black and white arrangement pattern of the pixel data. Since the connection relationship can be created based on pixel data taken out one line before, image memory can be saved significantly compared to the conventional method of storing image data for one screen. can. Here, the line memory has a general resolution of 16 pixels/laX and is approximately 19,000 bits in the longitudinal direction even in AO size.
A few kilobytes at most can cover sizes from A4 to AO, and having that much memory makes it possible to realize a hardware circuit that is not affected by image size or resolution.

In addition, since processing is performed in units of l-line scanning time, contours can be extracted in approximately the same time as the input time for one screen (maximum l-line delay time), which is significantly faster than the processing time of conventional methods. processing is now 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 the contour elements located at the rear end of the surface of the contour are described. As a result, a data string that has meaning as a contour element as a line or figure is obtained, so contours can be easily extracted in series units (for each closed line forming the contour). Furthermore, since run-length vector information and MH encoded data are created from the pixel array data of the command string and the coordinates of the pixel data, it is possible to obtain highly compressed data while reducing the amount of data analysis. can be easily created.

By using these contour vectors, vectorization that is faithful to the original image can be performed, and the vectorization performance is particularly good for curved portions.Moreover, enlargement and t1M small rotation operations can be performed easily.

[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, FIG. 1θ and FIG. 11 are explanatory diagrams showing the established relationship between pixel data and connection relationships, FIG. 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 the table update process and the position of pixel data, and FIG. 25 is an explanatory diagram showing the pixel pattern of the l line.
FIG. 26 is a flowchart showing run-length vectorization processing, FIG. 27 is an explanatory diagram showing a video data table,
FIG. 28 is a flowchart showing the MH encoding process,
Figure 9 is an explanatory diagram showing the contour vector series table, No. 30.
Figure a = d is an explanatory diagram of the contour vector series processing, the third
FIG. 1 is an explanatory diagram showing a full length information table, FIG. 32 is a flowchart showing short vector removal processing, and FIG. 33 is an explanatory diagram showing a conventional outline pixel extraction mode. 1.4. ...Contour extraction section, 2.43..Contour analysis section,
2. 23... processing section, 31-3. ...Memory, 4
3A to 43c...processing unit, 9...main memory. Fig. 1: Configuration diagram of the present invention Fig. 2: Explanation of raster scan Fig. 3: Explanation of contour element table Fig. 4: a Contour connection table ) (b)Xn@
XnXn-IXn Fig. 9 41... Internal bus 5... Binary image input processing unit 42 - Contour extraction unit 6 - Binary image input device 43 Contour analysis 13 7
・Main control unit 4s~4x ・Processing unit 8
Human processing unit 4 - Internal memory 9 - Main memory 45 - Bus interface Figure 12 Figure 13 Explanation diagram of element data Figure 13 Explanation diagram of connection flags Explanation diagram of command string Figure 15 Circuit diagram of wheel output section Figure 16: Explanation of connection flag data Figure 18: Illustration of isolated pixel patterns (A) (B) (C)
(d) Fig. 19: Flowchart of overall processing of the contour analysis section Fig. 20: Flowchart of update processing Fig. 21 Fig. 4: Flowchart of processing 1 Fig. 23: Flowchart of processing 2 Fig. 23: Flowchart of processing 3 Fig. 24: Update processing and pixel data D+ Figure 25 Explanatory diagram of the pixel pattern of one line Figure 27 Image data table Figure 29 Contour vector series table Figure 31 Full length information table 1 (a) (C)・1 and 1F% column. (b) P) (Q) (d) P+ (XJ, y+) Figure 32 Flowchart of short vector removal processing Figure 33 Diagram of conventional contour pixel extraction mode

Claims (2)

[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 connection/pattern code is generated based on the pixel data extracted before the line, and also includes information on the connection relationship and information on the black and white arrangement pattern of the pixel data, and this connection/pattern code and the above two a contour extraction unit that creates and outputs a command string including pixel array data of one line of the pixel data of pixels x 2 pixels; A contour element for attaching a unique code and describing, for each contour element, its coordinates and direction, 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, respectively. a table, a contour management table for recording the codes of the contour elements located at the leading edge and the trailing edge for each contour, and the X coordinates of the contour elements arranged in the raster scan direction and the contour elements of the end-connected contour elements whose front edge or trailing edge is positioned at the coordinates. a first memory for storing a contour connection table for writing a code and a distinction between the front and rear ends of the terminal connection end of the contour element in correspondence with each other; and a second memory for storing run-length vector information. a third memory for storing a contour vector series table for recording information related to the contour vector group; and a third memory for storing a contour vector series table for recording information related to the contour vector group; A first processing unit that updates the description of each table in the memory and updates the code of the other contour elements in the contour element table by referring to the contour connection table, and the pixel array data of the command string. a second processing unit that creates run length vector information that sets the starting point and length of a black run based on the X coordinate of the pixel data and stores it in the second memory; Among the points constituting the contour pixel series, search for the maximum point that is the maximum when viewed from the starting point, find the point on the contour that is the maximum distance from the straight line connecting this maximum point and the starting point, and connect this point to the starting point. By repeating the same process for the straight line connecting , find the point Q before the maximum distance becomes less than the threshold, extract the vector connecting this point Q and the starting point as a contour vector, Next, a third processing unit extracts contour vectors by performing similar processing using the point Q as a starting point, and records information related to the contour vector group thus obtained in the contour vector series table. An image processing device comprising a contour analysis section. (2) 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 connection/pattern code is generated based on the pixel data extracted before the line, and also includes information on the connection relationship and information on the black and white arrangement pattern of the pixel data, and this connection/pattern code and the above two a contour extraction unit that creates and outputs a command string including pixel array data of one line of the pixel data of pixels x 2 pixels; A contour element for attaching a unique code and describing, for each contour element, its coordinates and direction, 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, respectively. a table, a contour management table for recording the codes of the contour elements located at the leading edge and the trailing edge for each contour, and the X coordinates of the contour elements arranged in the raster scan direction and the contour elements of the end-connected contour elements whose front edge or trailing edge is positioned at the coordinates. a first memory for storing a contour connection table for describing a code and a distinction between the front and rear ends of its contour element in correspondence; and a first memory for storing a code word of a one-dimensional encoding method; a second memory for storing a contour vector series table for recording information related to the contour vector group; a first processing unit that updates the description of each table in the first memory, and updates the code of the other contour elements in the contour element table by referring to the contour connection table, and the command string; A second step of determining the starting point and ending point coordinates of the black run and white run based on the pixel array data and the X coordinate of the pixel data, creating a code word of the one-dimensional encoding method, and storing it in the second memory. a processing unit that searches the contour element table for a maximum point that is the maximum when viewed from the starting point among the points constituting one contour pixel series, and searches the contour element table for the maximum point that is the maximum when viewed from the starting point, and searches for the maximum point on the contour that is the maximum distance from the straight line connecting this maximum point and the starting point. By finding the point Q and repeating the same process for the straight line connecting this point and the starting point, find the point Q before the maximum distance becomes less than the threshold, and connect this point Q and the starting point. The connecting vector is extracted as a contour vector, and then a contour vector is extracted by performing the same processing using the point Q as a starting point, and information related to the contour vector group thus obtained is stored in the contour vector series table. The third item described in
An image processing device comprising: a processing section; and a contour analysis section having a processing section. (3) The second processing unit further calculates the start point and end point coordinates of the black run and white run based on the pixel array data of the command string and the X coordinate of the pixel data, and 2. The image processing apparatus according to claim 1, further comprising a function of creating a word and storing it in said second memory.