JPH01273186A - Contour detector - Google Patents

Abstract

PURPOSE:To reduce the capacity of an image memory by removing contour picture elements whose total number is smaller than a threshold value from a contour picture element sequence when the total number of the picture elements is smaller than the threshold value. CONSTITUTION:For example, when a command sequence regarding picture element data is inputted, contour elements shown by a dotted line are registered in a contour element table, their directions and coordinates are written, and the numbers of other contour elements which are connected before and after the contour elements Cj are written in a connection element number field. Then when the command sequence is inputted to a contour analysis part 2 and processed, the total number of contour picture elements in the picture element sequence is found and compared with the threshold value. Further, a short picture element sequence in the contour picture element sequence is removed as meaningless according to the comparison result. Consequently, the capacity of the image memory is 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. Based on the pixel data taken out one line before, for example, the connection relationship between contour pixels in the raster scan Y direction is determined, and a command string containing information on this relationship and the arrangement pattern of the pixel data is created, Furthermore, based on these command sequences, a table is created in which the contour elements are serialized, the total number of contour pixels in the pixel series is obtained from the table, and the total number of contour pixels in the pixel series is obtained, and the total number of contour pixels in the pixel series is obtained and compared with a threshold value. The configuration and processing time are not affected by the image size or resolution, and the outline can be extracted easily. Short pixel sequences are removed from the pixel sequence to reduce noise components, and the device This is to improve its own performance.

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

Among these, the conventional method for extracting contour pixels of an object from binary image data exhibits an operation as shown in FIG. 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 the points adjacent to this point PI and
Extract the contour pixels of.

D0 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 it is not affected by the image memory capacity, hardware configuration, or processing time, and it also makes it easy to extract contours. It is an object of the present invention to provide a contour detection device that can reduce noise components and improve the performance of the device itself.

E6 Means for Solving Problems FIG. 1 is a diagram showing the configuration of the present invention, and 1 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 vertical vi 2 pixels x 2 pixels along the scan line. Based on this pixel data, a command sequence for contour detection is created and output to the contour analysis section 2 at the subsequent stage. The contour analysis section 2 updates the descriptions of the contour element table, the contour management table i, and the contour connection table in the table storage section 3 based on the command string, and removes short pixel sequences of the contour pixel sequence using the removal section 31. Then, the code located in that pixel series is deleted from the contour management table.

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 to describe the coordinates arranged in the direction, the code of an unconnected contour element whose front end or rear end exists at the coordinate, and the distinction between the front and rear ends of the unconnected end of the contour element in correspondence with each other.

The command string output from the F9 action 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 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 XI'l-1, which is one position before the coordinate, is connected. Furthermore, the 6th
In the figure, frames with O marks indicate black pixels, and frames without O marks indicate white pixels.

For example, if we focus on the large frame in FIG. 6(a), the connection/pattern code in this case includes the above-mentioned connection information and information on the black and white array pattern within the large 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 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 C4 is entered in the rear connection column related to the column of the contour element Cj, and Ci is entered in the front connection gutter related to the column of the contour element Cj. Furthermore, the number of the contour to which the contour element Cj belongs, St 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.
,-a.

is defined, and in the case of four connections, four directions, up, down, left and right, are defined. Then, regarding the contour number St in the contour management table, the tip contour element number column is updated from C4 to Cj, and regarding the X coordinate of the pixel data in the contour connection table, the forward connection column of the unconnected contour element number is updated to Ci. Update from Cj to Cj. By the way, in actual processing, the contour element to be connected to the contour element C4 is clarified by the contour connection table, so the description of Cj of the front connection gutter related to the contour element number Ci column of the contour element table is This is done by referring to the 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.

As described above, when the command sequence is taken into the contour analysis unit 2 and processed, the total number of contour pixels in the pixel series is further determined and compared with a threshold value. From this comparison result, short pixel sequences of the contour pixel sequence are removed as meaningless data.

G. Embodiment In an embodiment of the present invention, an internal bus 41 as shown in FIG.
The contour extraction section 42, the contour analysis section 43, and the internal memory 44 as a table storage section are connected to the contour extraction section 42, the contour analysis section 43, and an internal memory 44 as a table storage section, and information is exchanged between each section through an internal bus 4I. The bus interface 4. The contour detecting device 4 is connected to the main bus 46 via the contour detecting device 4, thereby providing information obtained by the contour detecting device 4 to external equipment.

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 ×
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 (d, -d,
), and the parts where "N and rOJ stand correspond to black pixels and white pixels, respectively. Also, as shown in Fig. The presence or absence of a forward connection contour element at the X coordinate Xn-1 of pixel data and the presence or absence of a forward connection contour element at the It is a connection flag indicating the presence or absence of a backward connection contour element at the X coordinate x1 and the presence or absence of a backward connection contour element at the X coordinate x1, and Ill and rOJ mean connection and no connection, respectively.For example, FIG. Since the front end of the outline element is connected to the pixel area at the coordinate position (x,, y, ,), the connection flag in the pixel area surrounded by the large frame is shown on the left side of the connection flag column in Figure 10. Only the top right frame, such as the fifth frame, is represented by the rlJ window.

In FIGS. 1O 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. When the combination is marked with O, it is necessary to perform processing in the contour analysis section 43, and a connection/pattern code corresponding to the combination is generated in the contour extraction section 4t. 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 relationship diagrams shown in FIG. 1O and FIG. 11 are created corresponding to 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, AI is a read ready code, which invalidates the command sequence when the combination of pixel data and connection flag corresponds to x, or X and Δ in FIGS. 1O and 11. A is the X coordinate of pixel data,
A.

A4 is a code indicating black and white of two pixels arranged on the left and right sides of the lower side of the pixel data, and A a and A- are required when performing run length conversion. A.

is 1 page, EOP (END) indicates the end of (all lines)
OF PAGE) code, A6 is the EOR (END OF ROW) code indicating the end of l line, A,
is the connection/pattern code.

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

Pixel data is input to the pixel data latch 101 from the signal line 5 and a line memory 105, which will be described later. This latch 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.

The address generation circuit 108 generates the X coordinate and the X coordinate 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 +09, 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 sequence.

The line memory 105 stores the X coordinate that is one smaller than the X coordinate generated by the address generation circuit 108, that is, the
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 6512), and the front end of the contour element is connected to a certain pixel in the pixel data. and when the contour element is not connected to any other contour element, data of logical rlJ is written to the address corresponding to the X coordinate of the pixel.

On the other hand, the rear flag memory 1047 also has the same number of addresses as the coordinates, but this memory contains the following information: When the rear end of a contour element is connected to a certain pixel and that contour element is not connected to any other contour element, Logical rN data is written to the address corresponding to the X coordinate of that 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 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 X coordinates generated by the address generation circuit I08. 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 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 4 to perform contour tracing based on the four pixel data output from the pixel data latch 1O1 and the flag data output from the connection flag latch 102. At this time, the command generation circuit +03 sends a read ready signal indicating whether or not processing is necessary through the signal line 6, and sends the connection/pattern code through the signal line 7 to the contour analysis unit 4. send to

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 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 d of pixels, that is, four pixels adjacent to each other. -d, is latched.

The line memory 105 takes in the pixel data d1 output by the pixel data ludge +01, thereby generating the pixel data of the previous row, that is, the pixel data d whose Y address is currently being input from the signal line 5.

One row of pixel data that is one row smaller than the Y address of is stored. Then, pixel data d is transmitted from the signal line 5. ,d+
When the pixel data dt and dz are sequentially input to the pixel data latch 101, the line memory 105 sequentially outputs the pixel data dt and dz to the same latch based on the address data output from the address generation circuit 108. As a result, the pixel data latch 101 receives four adjacent pixel data d. -d, can be latched.

The connection flag changing circuit 104 converts the pixel data d0 to d
, 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 field indicates that the value of the flag data is "0", and a blank field indicates that the flag data value is "1".

Specifically, since the rear end of the contour element Ca is connected to the pixel el, the rear connection flag data T1 of the X coordinate of this pixel is "1". Conversely, since the surface edge 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.
It is "1". All other flag data are "0" 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 change circuit 104 outputs connection flag data R3, T3 corresponding to the X coordinate of the processing target pixel on the right side.

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

The connection flag changing circuit 104 inputs the 4-bit connection flag data and the pixel data d from the pixel data latch 101.
. -d3 is accepted and the flag data after contour element tracking processing is obtained. That is, as shown in FIG. 17, the next contour element Cc is connected to the contour element cb in the pixel e2 through the tracking process, so the connection flag 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 above-mentioned change processing 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 processing into 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 101 and the 4-bit flag data from the connection flag latch 102, and also generates pixel data of 2 pixels x 2 pixels. 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 as shown in FIG.
When it corresponds to the O mark in FIG. 11, the read ready code is set to rlJ, and when it corresponds to the Δ mark or the X mark, it is set to "0". Additionally, an EOP signal indicating the end of one page is sent to the peripheral determination circuit 109 via the signal line 9.
A FOR signal indicating the end of the signal and I line is input manually, and as a result, an EOP code and a FOR signal are sent from there to signal line 6.
The code will be output. In this way, the signal line 6 is given the coordinate code indicating the X coordinate of the pixel data from the address generation circuit 108, as well as the EOP code and the FOR code.
These codes are given to the contour analysis section 4.

In the above, as in the above 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. The code becomes "0", so the contour analysis section 4. This is because no processing is being performed.

However, when performing run-length conversion, the read ready code becomes "1" for the patterns shown in FIGS.

Here, contour analysis section 4. The processing performed in Figures 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 EC)R is instructed, add one Y address and take in the command string; if not instructed, internal memory 43
Each table stored in (see Figures 3 to 5)
Update.

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

S T l . . . 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.

S T s: It is determined whether the edges of two contour elements that have already been generated exist in the 2 pixel x 2 pixel image data.

Next, the contents of processes 1 to 3 in FIG. 20 will be described. In process 1, as shown in FIG. 2.1, steps ST, -
ST is executed. Each step ST.

~ST, is as follows.

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

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

ST3...Write CI on both sides of the St-th leading edge contour element number and end edge 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. 22, step ST is performed.

~STs is executed. Each step ST, ~ST.

is as follows.

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

S T t...Determine the contour element number Cj of the connection destination from the output side of the contour connection table, and rewrite the side to N0NE.

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.

'ST, ... Enter the information corresponding to the Ci-th direction and coordinate column of the contour element table, Cj in the corresponding one of the forward connection and backward connection columns, N0NE in the other, and Sk in the belonging contour number column. Write each.

S T 5: Rewrite the corresponding one of the Sk-th tip contour element number and end contour element number columns of the contour management table to Ci.

ST,...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 STs is as follows.

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

S T t...Cj is written in the Ci-th forward connection and backward connection of the contour element table, whichever is applicable, and the contour number Sk to which Ci belongs is obtained from the column of belonging contour number.

STs...Write C1 in the applicable one of the Cj-th forward connection and backward connection in the contour element table, and also write the contour number SQ to which Cj belongs from the belonging contour number column
seek.

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

STs: Obtain the contour element number Cm which is not the connection target 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.

STe: Of the S12th 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 i to 3 and the extraction position of 2 pixels x 2 pixels pixel data, in which 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 D, corresponds to processing 1, 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 strings generated for D correspond to the cases in which Sk and S12 are equal and different in process 3, respectively.

After performing the above-described processing, next the short series of contour pixel series is removed. The flowchart of this process is shown in the 25th section.
As shown in the figure. In FIG. 25, step S T + determines the total number N of contour pixels in the pixel sequence. The determined total number N is compared with a threshold value N+h in step S T 2. Step ST3 is a step for determining whether pJ > N Ih, and if YES in step ST3, the process ends. Also, if NO in step ST3, step ST
Proceeding to step 4, short sequences of the contour pixel sequence are removed from the contour pixel sequence as meaningless data (noise). At this time, information on short pixel sequences is deleted from the table shown in FIG.

H9 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 of pixel data, and the black and white arrangement pattern of the pixel data. Since the connection relationship can be created based on the pixel data taken out one line before, the image memory can be saved significantly compared to the conventional method of storing image data for one screen. . Here, the line memory has a typical resolution of 16 pixels/ZX.
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 1-line scanning time, contours can be extracted in approximately the same time as the input time for one screen (maximum delay time of 2 minutes), 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 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, by removing short pixel sequences from the outline pixel sequence, meaningless noise components are reduced and the performance of the apparatus itself is improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the hardware configuration of the present invention,
FIG. 2 is an explanatory diagram showing the state of raster scanning, FIG. 3 is an explanatory diagram showing the contour element table, FIG. 4 is an explanatory diagram showing the contour management table, FIG. 5 is an explanatory diagram showing the contour connection table, Figure 6 (a). (b) is an explanatory diagram showing the relationship between pixel data and contour elements, FIG. 7 is an explanatory diagram showing the connection state between contour elements, FIG. 8 is an explanatory diagram showing the direction of contour elements, and FIG. is a configuration diagram showing the hardware configuration of the present invention, FIGS. 10 and 1t are explanatory diagrams showing established relationships 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 table update processing and the position of pixel data. FIG. The flowchart in FIG. 26 is an explanatory diagram showing a conventional outline pixel extraction mode. ■, 4. ... Contour extraction section, 2.43 ... Contour analysis section, 3 ... Table storage section, 4 ... Contour detection device, 4
4... Internal memory, 31... Short pixel sequence removal unit. Fig. 1 Ellipse of the present invention Fig. 1-11 Contour extraction unit 2 - Contour analysis unit 3 - Table storage unit 31 - Short pixel sequence removal unit Fig. 2 Illustration of raster scan Fig. 3 Explanatory diagram of contour element table Figure 4 Figure 5 Contour connection table Figure 6 Relationship between pixel data and contour elements Countries (a) (b) Xn
-I Xn --- Bus interface 46 --- Main bus No. 10 Diagram showing the establishment of the connection relationship between the pixel data and the connection relationship. Fig. 15: Circuit diagram of the contour extraction unit Fig. 16: Explanation of the connection flag data Fig. 17: Explanation of the connection flag data Fig. 18: Illustration of the pattern of isolated pixels )(c)
(D) Figure 19: Flowchart of overall processing of the contour analysis section Figure 20: Flowchart of update processing Figure 21 Figure 22: Flowchart of process 1 Figure 23: Flowchart of process 2 Figure 24: Flowchart of process 3 Figure 24: Update processing and both options Relation diagram with data position D+ Figure 25 Removal flowchart

Claims (1)

[Claims] (1) In a device that detects the contour corresponding to the boundary between black and white based on binary pixel data corresponding to black and white obtained by raster scanning the subject, pixel data of 2 pixels x 2 pixels horizontally and vertically is converted into a scan line. The connection relationship between the contour element corresponding to the vector connecting two adjacent black pixels and the pixel related to the pixel data is calculated as 1.
an outline extraction unit that creates and outputs a command string based on pixel data extracted before a line, and that also includes information on the connection relationship and information on a black and white arrangement pattern of the pixel data; and the outline element. A unique code is attached to each contour consisting of a group of contour elements, and each contour element is connected to its coordinates and direction, the code of the contour to which the contour element belongs, and the front and rear of the contour element. A contour element table for recording the codes of contour elements located at the tip and end of each contour, a contour management table for recording the codes of the contour elements located at the tip and end of each contour, and the X coordinates aligned in the raster scan direction a table storage unit for storing a contour connection table for describing a code of an unconnected contour element in which a front end or a rear end is located and a distinction between the front and rear ends of the unconnected end of the contour element in correspondence; updating the description of each table in the table storage section based on a command string from the contour extraction section, and updating the codes of the other contour elements in the contour element table with reference to the contour connection table; A contour analysis unit is provided which calculates the total number of contour pixels in the contour pixel series, compares the total number with a threshold value, and performs processing to remove the contour pixels from the contour pixel series when the total number of contour pixels is smaller than the threshold value. A contour detection device characterized by a contour detection device.