JP2846486B2 - Image input device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image input device for inputting an image drawn on a drawing or the like as image data, converting the image data into numerical information (vector data) that can be processed and handled by a computer, and storing the converted numerical information. .

[0002]

2. Description of the Related Art With the spread of CAD systems,
2. Description of the Related Art There has been proposed an image input device which reads an image drawn on a drawing or the like by a photoelectric conversion element, recognizes the image data (raster data) as a line or a contour, converts the image data into corresponding vector data, and stores the converted vector data. Hereinafter, an outline of image recognition by a conventional image input device will be described with reference to FIGS. FIG. 10 is an explanatory diagram of an input target drawing of the image input device. In FIG. 10, reference numeral 1 denotes a drawing drawn on the recording paper 2 and 2 denotes a drawing drawn on the recording paper 1. The drawing 2 includes a hatched rectangular filled portion (filled image portion) 3 and two straight lines (line drawing portions) 4 extending from the filled image portion 3 in both directions. FIG. 11 is an enlarged view of FIG. 2 depicted in FIG. In the figure, the same parts as those in FIG. 10 are denoted by the same reference numerals. W ₁ indicates the width of the line drawing portion 4, W ₂ and W ₃ indicate the width of the outline of the filled image portion 3 extending vertically from the line drawing portion 3,
It is equal to the width W ₂ and the width W _3. Here, the width W ₁ comprises 11 pixels, the width W ₂ (W ₃₎ is intended to include 15 pixels.
Such a drawing 2 is first read by the photoelectric conversion element, binarized by a predetermined threshold value, and stored in the image storage unit. This storage is performed using two bits (background bit and skeleton line bit). The background bit stores original image data as it is until the end, and the skeleton line bit stores data obtained during the processing. Has become. After storing in the image storage unit, first, the image data of the background bit is copied to the core line bit of the same address. Next, thinning processing, line tracing processing, and contour line extraction processing are sequentially performed on the background bit image data. Since these processes are well known, only the outline thereof will be described with reference to FIGS. The thinning processing is performed on image data obtained by the photoelectric conversion element using a virtual mask. FIG. 12 is a plan view of the mask. In FIG. 12, reference numeral 5 denotes a virtual mask,
(3 × 3) areas. Reference numeral 50 denotes a central region of the mask 5. One pixel corresponds to one region. In the thinning process, the image data of the background bit is scanned by the mask 5 in the vertical direction in FIG. During this scanning, the area 50 is always noticed,
, The data of the core line bit corresponding to the pixel is set to 0. Note that the “edge” refers to a state in which two or more pixel groups separated in the mask 5 do not exist when the pixels in the region 50 are excluded. For example, when the mask 5 corresponds to the position A in FIG. 11, the pixels in each region of the mask 5 are in the state on the left side in FIG. 12, and even if the pixels in the region 50 are omitted, no separated pixel group is generated (the region 50). Is the end), and the data of the core line bit corresponding to the pixel is set to 0. Similarly, when the mask 5 corresponds to the position B in FIG. 11, the pixels of the region 50 are at the end, and the data of the core line bit is set to 0. For the sake of simplicity, for example, if 11 pixels or less are defined as a line drawing part and 12 pixels or more are defined as a solid drawing part, the image data of the core bit is indicated by a solid line in FIG. Data. FIG. 13 is an enlarged view of the drawing after the thinning processing. In the drawing, reference numeral 10 denotes a drawing corresponding to the data stored in the core line bits after the thinning processing, 13 denotes a solid image portion, and 14 denotes a line image portion. The drawing (the drawing 2 shown in FIG. 11) corresponding to the data stored in the background bit is indicated by a broken line. The line drawing section 14 is a continuous line having a width of one pixel. Next, a line tracing process is performed on the data of FIG. The line tracing process is also performed by using the mask 5 shown in FIG. 12, and when the pixel is present only in the same direction region as seen from the region 50, this is traced. When the pixel appears in the other direction region, the point is traced. The end point is set, and the start point and the end point of the tracking are stored as vector data in another storage unit. It is considered that such a method of using the mask 5 is easily understood from the method of using the mask in the thinning processing (the same applies to the following contour line extraction processing). In FIG. 10, two line drawing units 14 are stored as vector data. Next, a contour line extraction process is performed on the remaining painted image portion 13. This contour line extraction processing is also performed using the mask 5 shown in FIG. 12, and the edge of the solid image portion 13 is traced from the region 50, and a direction change point of the pixel is searched. These conversion points (feature points) are stored in another storage unit as vector data. By the above processing, Drawing 2 shown in FIG. 10 is obtained as vector data that can be processed and handled by the computer.

[0003]

However, in the above-mentioned prior art, since the contour line extraction processing is performed on the data subjected to the thinning processing, the following inconvenience has occurred. This will be described with reference to FIG. FIG. 14 is an enlarged view of the solid image portion. In the figure, a broken line 3 is a solid image portion corresponding to the original image data shown in FIG. 11, and a solid line 13 is a solid image portion corresponding to the data after the thinning processing. The contour line extraction process is performed on the filled image portion 13, and the vector data obtained by this process is data that is reduced from the original image data (data of the filled image portion 3) as is apparent from the drawing. Becomes In the case of the above example, the line drawing section 4 becomes a line drawing section 14 having a width of one pixel by repeating the thinning processing five times. At the same time, the line drawing section 3 is also subjected to thinning. After the processing, the filled image portion 13 has its surroundings deleted by 5 pixels. Therefore, there has been a problem that accurate vector data cannot be obtained for a solid image portion of the drawing.
An object of the present invention is to solve the above problems in the prior art,
An object of the present invention is to provide an image input device capable of obtaining accurate data even for a solid image portion.

[0004]

According to the present invention, there is provided a scanning input section for scanning a drawing, binarizing the drawing with a predetermined threshold value, and outputting the image data as image data, and storing the image data. A storage unit, a thinning unit that extracts each image data from the storage unit and thins the line data, a line tracing unit that tracks a line drawing unit obtained by the thinning unit and stores the line drawing data as line data, And an outline extracting means for storing the outline of the obtained painted image portion as traced outline data, wherein the outline data to be extracted by the outline extracting means is subjected to thinning by the thinning means. The present invention is characterized in that a contour expanding means for expanding according to the degree is provided. Further, another aspect of the present invention is the image input device, wherein the contour in the contour is obtained based on the contour data obtained by the contour line extracting means and the data obtained by the thinning means via the contour expanding means. A detection means for detecting the presence or absence of a line segment and an erasing means for erasing a line segment when the detection means detects the line segment are provided.

[0005]

Before executing the contour extracting means, a process of extending the contour of the solid image obtained by the thinning processing means in accordance with the degree of thinning is performed. To perform contour line extraction processing. Also, in the original drawing, if the line drawing portion and the filled image portion are in contact with or close to each other, and the fill image portion is extended as described above, the line drawing portion data is stored inside the closed loop forming the expanded outline. Since the line drawing data exists, the line drawing part data is deleted.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments. FIG. 1 is a block diagram of an image input device according to an embodiment of the present invention. In the figure, reference numeral 20 denotes a scanning input unit provided with a photoelectric conversion element, which reads a drawing drawn on a recording paper and outputs it as image data binarized by a predetermined threshold value. Reference numeral 21 denotes an image storage unit that stores image data output from the scan input unit 20. The image storage unit 21 has the background bit and the core line bit for one image data as described above, and the image data from the scan input unit 20 is stored in the background bit. Reference numeral 22 denotes an image calculation unit which performs a thinning process and a contour expansion process (thickening process) described later by a logical operation based on the image data extracted from the background bits of the image storage unit 21, and the result is stored in the image storage unit 21. Are stored in the core bit. Reference numeral 23 denotes a recognition processing unit that performs the above-described line tracing processing, contour extraction processing, and theoretical calculation based on the data stored in the core line bits of the image storage unit 21.
Then, an extension elimination process described later is performed. Reference numeral 24 denotes a coordinate sequence data storage unit that stores vector data (coordinate data) obtained by the processing of the recognition processing unit 23.

Next, the operation of this embodiment will be described with reference to FIGS. In the present embodiment, the drawing shown in FIG. 3 which is slightly more complicated than the drawing shown in FIG. 10 will be described as an example. FIG. 3 is an explanatory diagram of an input target drawing of the image input device, similarly to FIG. In FIG. 3, reference numeral 1 denotes a recording sheet, and reference numeral 30 denotes a drawing drawn on the recording sheet 1. The drawing 30 is composed of a hatched portion (filled image portion) 31 in which a part of a rectangle protrudes into a triangle and is hatched, and one straight line (line drawing portion) 32 extending rightward from the filled image portion 31 to the left. Have been.
FIG. 4 is an enlarged view of the drawing 30 depicted in FIG. In the figure,
The same parts as those in FIG. 3 are denoted by the same reference numerals. W _{1 to} W ₃
Indicates the same dimensions as those shown in FIG. Reference numeral 31a denotes a square portion of the filled image portion 31, and reference numeral 31b denotes a triangular projecting portion of the filled image portion 31. Vertical dimension of the distal end portion of the triangular projecting portion 31b has a size W ₁ below. In this embodiment, processing is performed on such a drawing 30 according to the flowchart shown in FIG. That is, first, the image calculation unit 2
2 fetches the image data shown in FIG. 4 from the image storage unit 21 and outputs a predetermined line width (11 in accordance with the above example).
Pixels. ) Is performed (FIG. 2).
Procedure S ₁ ). Since the thinning processing, the line tracing processing, and the contour extraction processing described later have been described above, the description will be omitted. Figure 5 is an enlarged view of the drawing after the thinning processing steps S _1. In FIG. 5, 30 indicated by a broken line
Is the same drawing as that shown in FIG. 4, and 40 is a figure after the thinning processing. Reference numeral 41 denotes a solid image portion corresponding to the solid image portion 31, reference numeral 42 denotes a line image portion corresponding to the straight line 32, and reference numeral 43 denotes a line image portion resulting from thinning of the distal end portion of the triangular protrusion 31b. The result of the thinning is stored in the core bit of the image storage unit 21. In FIG. 5, P _{1 to} P ₄ indicate the leading end points of the line drawing part, and the parentheses indicate the coordinates.

[0008] Next, the recognition processing section 23 is operated by the image storage section 21.
Then, data is extracted from the core line bit of ( ₁ ) and a line tracing process is performed (step S ₂ ). By this line tracking processing, the line drawing units 42, 4
3 are extracted as line segments, and these are stored in the coordinate sequence data storage unit 24 as vector data. That is, the coordinates (x _1, y ₁₎ of the center point _{P 1 ~P 4 ~ (x 4} , y 4) are stored. When this storage is completed, the image data of the line drawing units 42 and 43 stored in the core line bit of the image storage unit 21 is deleted, and only the image data of the solid image unit 41 remains. Next, the image calculation unit 22 takes out the image data of the solid image unit 41 remaining in the core line bits of the image storage unit 21 and adds one pixel data to an area of one pixel around the thick line processing. It is carried out (Step S _3). This thick line processing is performed by the number of times of the thin line processing. According to the above example in which 11 pixels or less are recognized as a line drawing part, the thick line processing is executed five times. The result of this thickening process is shown in FIG. FIG. 6 is an enlarged view of the drawing after the thickening processing. In FIG. 6, reference numeral 31 shown by a solid line denotes a filled image portion which is the same as the original filled image portion of the drawing 30 as a result of the thick line processing, and broken line 41 denotes a filled image portion after the thinning process shown in FIG. P _{4 to} P ₁₀ indicate characteristic points (straight line direction conversion points) of the solid image portion 31, and the coordinates in parentheses indicate the coordinates. Step S ₃ of bolding process results again image storage unit 21
Are stored in the core bit. Then, it is checked whether or not excessive thickening processing has been performed, and if there is an excessive portion, it is corrected (step S ₄ ). The checking is performed by the image calculation unit 22 taking out the background bit data and the core line bit data at the same address in the image storage unit 21 and calculating the logical product of them. The result of the correction by this operation is stored again in the core bit. In this state, the recognition processing unit 23 extracts the image data of the fill image portion from the core wire-bit image storage unit 21 performs edge extraction processing for tracking the outline of fill-image portion 31 (Step S _5). Then, the coordinates of the feature points P _{4 to} P ₁₀ are sequentially stored as vector data in the coordinate sequence data storage unit 24. FIG. 8 shows the data stored in the coordinate sequence data storage unit 24 at this time. FIG. 8 is an explanatory diagram of the stored contents of the coordinate string data storage unit 24. In FIG. 8, M _{0 to} M ₂₉ are address names, and x ₁ , y _{1 to} x ₁₀ , y in data stored at each address.
Reference numeral ₁₀ denotes the coordinates shown in FIGS. Addresses M ₀ , M
The number of ₆ data "2" each tip point of the line drawing unit 43, the data "8" in the address M ₁₂ Fill picture 31
The data “0” at addresses M ₁ and M ₇ indicates an open figure of a line drawing, and the data “2” at address M ₁₃ indicates a contour line. That is, the addresses M ₀ , M ₁ , the addresses M ₆ , M ₇ and the addresses M ₁₂ , M ₁₃ are data representing the line types in the drawing, and the first two
The address is the coordinates of the start point of the line, and the last two addresses are the coordinates of the end point.

By the way, if a drawing is drawn according to the vector data shown in FIG. 8, a drawing as shown in FIG. 7 appears. FIG. 7 is an enlarged view of the painting section 31. In the figure, the same parts as those shown in FIG. 6 are denoted by the same reference numerals. 4
Reference numeral 20 denotes a part of the line drawing unit 42. As is clear from FIG. 7, the line drawing units 43 and 420 are present in the area of the solid image unit 31 and are completely unnecessary data (noise). Such unnecessary data is obtained by converting the data of the line drawing portion obtained by the thinning processing and the line tracing processing in steps S ₁ and S ₂ into the data in step S _3.
Are left in the area of the filled image portion due to the enlargement of the filled image portion by the thick line processing. In step S ₆ shown in FIG. 2 performs a process of erasing the unnecessary data.
That is, the recognition processing unit 23 stores the outline data of the solid image portion (addresses M _{14 to} M in FIG. 8) from the coordinate sequence data storage unit 24.
₂₉ data), the data of each line drawing part is sequentially taken out of these data, and a well-known inside / outside judgment is performed. Since the entire line drawing section 43 is in the area of the solid image section 31, all the data is erased. In addition, since the line drawing part 42 has a part 420 in the area, the intersection P ₂₀ with the contour line is obtained.
Is found (x ₂₀ , y ₂₀ ), and the line segment between the points P ₂₀ and P ₂ is deleted. After the erasure is completed, the data resulting from the erasure is stored in the coordinate sequence data storage unit 24 again. FIG. 9 shows the contents of the coordinate sequence data storage unit 24 in this state. FIG. 9 is an explanatory diagram of the storage contents of the coordinate string data storage unit 24. As is clear from FIG. 9, when there is erased data, the subsequent data is sequentially stored at the higher address. As described above, in the present embodiment, the contour line extraction processing is performed after the thick line processing is performed on the data after the thin line processing, so that the filled image portion is not reduced, and an accurate image Can be obtained. Further, even if unnecessary data is generated by the bolding processing, it is deleted by the erasing means, so that accurate vector data can be finally obtained. In addition, if the interval between the line drawing portion and the filled-in drawing portion is large and it is clear that unnecessary data does not remain in the filled-out drawing portion region even after performing the thickening process, it is needless to say that the line elimination is unnecessary. .

[0010]

As described above, according to the present invention, since the contour extraction processing is performed after performing the contour expansion on the data after the thinning processing, it is possible to reduce the size of the solid image portion. And an accurate image can be obtained. Further, even if unnecessary data is generated by the bolding processing, it is deleted by the erasing means, so that accurate vector data can be finally obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram of an image input device according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating the operation of the apparatus shown in FIG.

FIG. 3 is a plan view showing an input target drawing.

FIG. 4 is an enlarged view of the drawing shown in FIG. 3;

FIG. 5 is an enlarged view of the drawing shown in FIG. 3 after the thinning processing.

FIG. 6 is an enlarged view of a solid image portion after the thick and thin line processing of the drawing shown in FIG. 3;

FIG. 7 is an enlarged view of the drawing shown in FIG. 3 after a contour line extraction process.

FIG. 8 is an explanatory diagram of storage contents of a coordinate sequence data storage unit shown in FIG.

FIG. 9 is an explanatory diagram of storage contents of a coordinate sequence data storage unit shown in FIG. 1;

FIG. 10 is a plan view showing an input target drawing.

FIG. 11 is an enlarged view of the drawing shown in FIG. 10;

FIG. 12 is an explanatory diagram of a mask used for each processing.

FIG. 13 is an enlarged view of the drawing shown in FIG. 10 after the thinning processing.

FIG. 14 is an enlarged view of the drawing shown in FIG. 10 after the thinning processing.

[Explanation of symbols]

 Reference Signs List 20 scanning input unit 21 image storage unit 22 image calculation unit 23 recognition processing unit 24 coordinate sequence data storage unit

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Mitsuru Fujii 2100 Kamiimaizumi, Ebina City, Kanagawa Prefecture Inside Hitachi Seiko Co., Ltd. (72) Inventor Shigetaka Mizoguchi 2100 Kamiimaizumi, Ebina City, Kanagawa Prefecture Inside Hitachi Seiko Co., Ltd. (56) References JP-A-3-12786 (JP, A) JP-A-1-206470 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G06T 9/00-9/20

Claims (2)

(57) [Claims] 1. A scanning input unit which scans a drawing and binarizes it with a predetermined threshold value and outputs it as image data, a storage unit for storing these image data, and takes out each image data from this storage unit and thins it. Thinning means, a line tracing means for tracing the line drawing portion obtained by the thinning means and storing it as line data, and a contour for storing the contour of the solid drawing part obtained by the thinning means as tracing contour data An image input device comprising a line extracting unit, wherein an outline extending unit for expanding the outline data to be extracted by the outline extracting unit in accordance with a degree of thinning of the thinning unit is provided. Image input device. 2. The image input device according to claim 1, wherein
Detecting means for detecting the presence or absence of a line segment in the contour based on the contour data obtained by the contour line extracting means and the line data obtained by the thinning means via the contour expanding means; An image input device, comprising: an erasing means for erasing a line segment when the line segment is detected.