CN114897120A

CN114897120A - Dot code, dot code decoding method, system and electronic equipment

Info

Publication number: CN114897120A
Application number: CN202210822927.8A
Authority: CN
Inventors: 魏江力; 殷述军
Original assignee: Qingdao Luobo Technology Co ltd
Current assignee: Qingdao Luobo Technology Co ltd
Priority date: 2022-07-14
Filing date: 2022-07-14
Publication date: 2022-08-12
Anticipated expiration: 2042-07-14
Also published as: CN114897120B

Abstract

The invention relates to a dot code, a dot code decoding method, a dot code decoding system and electronic equipment, belonging to the technical field of dot matrix pens, wherein the dot code decoding method comprises the following steps: carrying out image contour detection on the point code image to obtain a barycentric coordinate of a code point contour; extracting a target area in the point code image by using the barycentric coordinates, and decoding the target area; if the extracted target area is a complete image element, obtaining the central coordinates of the dot matrix image element according to the element values in the array; if the extracted target area spans two different image primitives, splicing according to element values in the array to obtain central coordinates of the dot matrix image primitives; and correcting the coordinates of the dot matrix code image according to the central coordinates of the dot matrix image primitives to obtain the final coordinates of the dot matrix pen. The invention can effectively eliminate the arrangement interference of the information codes on the positioning codes by decoding the dot matrix codes of which the arrangement mode of the information codes is the regular cross or the oblique cross, thereby greatly improving the reading accuracy of the information codes.

Description

Dot code, dot code decoding method, system and electronic equipment

Technical Field

The invention relates to the technical field of dot matrix pens, in particular to a dot matrix code, a dot code decoding method, a dot code decoding system and electronic equipment.

Background

The dot matrix pen is an intelligent pen, and acquires the dot matrix code printed or printed on a medium through a camera to acquire the position of a pen point on the medium, page number and other related information. The camera is a micro camera and is arranged at the pen point. An infrared light emitting tube is arranged at the pen point to emit infrared light, and the infrared light is reflected to the inside of the micro camera through the surface of the medium to form a point code image. The dot matrix code is small dots arranged on the surface of the medium according to a specific rule, namely, the code, the small dots can be square or round, the side length or the diameter is about 0.1 millimeter, and the normal writing of a user on the medium is basically not influenced. In writing track application, in order to obtain the track written by the pen, the lattice code needs to continuously acquire the position of the pen point, the page number and other relevant information. In general, dot codes are arranged in dot code elements, and the entire writing medium is covered with dot code elements, each dot code element occupies a small position, and the small position codes contain coordinate, page number and other information.

The encoding of the dot matrix code generally comprises three elements of a positioning code, a direction code and an information code, wherein the positioning code and the direction code are used for positioning the information code and characterizing the direction of the information code.

In the prior art, since the arrangement of the information codes is fixed, there is a possibility that information code points continuously located at the same position may appear, for example, in a certain frame image, points at positions 0 in a certain column may form a linear arrangement, which may affect the determination of the positioning code.

Disclosure of Invention

To solve the above problems, embodiments of the present invention provide a dot code, a dot code decoding method, a dot code decoding system, and an electronic device.

A lattice code, comprising:

at least one dot matrix image primitive comprising a plurality of bins; the positioning grids are provided with information codes, and the arrangement mode of the information codes is a regular cross or an oblique cross;

the positioning grids are square, and the arrangement mode of the information codes in the positioning grids can represent the direction of the image elements;

each dot matrix image element is divided into 4 positioning grids, each positioning grid is provided with 4 information codes, the arrangement mode of the positions of the 4 information codes adopts mixed coding of a positive cross and an oblique cross, and the arrangement mode of the positive cross and the oblique cross in each positioning grid is different from the arrangement mode of the positive cross and the oblique cross in the other 3 positioning grids;

the arrangement mode of the information codes in the positioning grids is in the horizontal, vertical or 45-degree oblique line direction, and more than 3 same positive crosses or oblique crosses cannot appear.

The invention also provides a point code decoding method, which comprises the following steps:

step 1: acquiring a point code image;

step 2: carrying out image contour detection on the point code image to obtain barycentric coordinates of code point contours;

and step 3: extracting a target area with the same size as the image element in the point code image by using the barycentric coordinates;

and 4, step 4: decoding the target area to obtain a 4 x 4 array, and judging the direction of the dot code image and the integrity of the target area according to the array element value;

and 5: if the extracted target area is a complete image element, obtaining the central coordinates of the dot matrix image element according to the element values in the array;

step 6: if the extracted target area spans two different image elements, splicing according to element values in the array to obtain a central coordinate of a dot matrix image element containing a directional positioning grid;

and 7: and correcting the coordinates of the pen point relative to the coordinates of the dot code image according to the central coordinates of the dot matrix image elements and the directions of the dot codes to obtain the final coordinates of the dot matrix pen.

The invention also provides a point code decoding system, which comprises:

the point code image acquisition module is used for acquiring a point code image;

the contour detection module is used for carrying out image contour detection on the point code image to obtain a barycentric coordinate of a code point contour;

the dot matrix image element extraction module is used for extracting a target area with the same size as the image element in the dot code image by using the barycentric coordinates;

the decoding judgment module is used for decoding the target area to obtain a 4 x 4 array, and judging the direction of the dot matrix code image and the integrity of the target area according to the array element value;

the first decoding execution module is used for obtaining the central coordinates of the dot matrix image primitives according to the element values in the array when the extracted target area is a complete image primitive;

the first decoding execution module is used for splicing the extracted target area according to the element values in the array when the target area spans two different image elements to obtain the central coordinates of the dot matrix image elements containing the directional positioning grids;

and the correction module is used for correcting the coordinates of the pen point relative to the dot code image according to the central coordinates of the dot matrix image elements and the direction of the dot code to obtain the final coordinates of the dot matrix pen.

The invention further provides an electronic device, which comprises a bus, a transceiver, a memory, a processor and a computer program stored on the memory and capable of running on the processor, wherein the transceiver, the memory and the processor are connected through the bus, and when the computer program is executed by the processor, the steps in the point code decoding method are realized.

According to the specific embodiment provided by the invention, the invention discloses the following technical effects:

the invention relates to a dot code, a dot code decoding method, a dot code decoding system and electronic equipment, wherein the method comprises the following steps: carrying out image contour detection on the point code image to obtain a barycentric coordinate of a code point contour; extracting dot matrix image primitives in the dot code image; decoding the dot matrix image elements to obtain a 4 multiplied by 4 array; obtaining the central coordinates of the dot matrix image primitives according to the element values in the array; and correcting the coordinates according to the central coordinates of the dot matrix image primitives and the barycentric coordinates of the code point outlines to obtain the final coordinates of the dot matrix pen. The invention can effectively eliminate the arrangement interference of the information codes on the positioning codes by decoding the dot matrix codes of which the arrangement mode of the information codes is the regular cross or the oblique cross, thereby greatly improving the reading accuracy of the information codes.

In order to make the aforementioned and other objects, features and advantages of the present invention comprehensible, preferred embodiments accompanied with figures are described in detail below.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic diagram of a dot matrix image element provided by the present invention;

FIG. 2 is a schematic diagram of an information code arrangement according to the present invention;

FIG. 3 is a schematic diagram of an information code distribution method in an embodiment of the present invention; wherein, fig. 3 (a) shows a schematic diagram of a regular cross arrangement, and fig. 3 (b) shows a schematic diagram of an oblique cross arrangement;

fig. 4 is a schematic diagram of a point code image collected in a camera in an embodiment provided by the present invention;

FIG. 5 is a schematic diagram of a preprocessed dot code image according to the present invention;

fig. 6 is a Hough transformation schematic diagram of a point code image in the embodiment provided by the present invention;

FIG. 7 is a schematic diagram of affine transformation of a point code image according to an embodiment of the present invention;

FIG. 8 is a schematic diagram of a preliminary decoded dot matrix image primitive provided by the present invention; wherein (a) in fig. 8 represents a schematic diagram of a non-rotated dot matrix image element, and (b) in fig. 8 represents a schematic diagram of a rotated dot matrix image element;

fig. 9 is a schematic diagram of a direction mark grid in an embodiment provided by the present invention.

Detailed Description

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like, indicate orientations and positional relationships based on those shown in the drawings, and are used only for convenience of description and simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be considered as limiting the present invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

The invention aims to provide a dot code, a dot code decoding method, a dot code decoding system and electronic equipment, which can effectively eliminate the arrangement interference of information codes on positioning codes.

Referring to fig. 1, a lattice code according to the present invention includes:

at least one dot matrix image primitive comprising a plurality of bins; the positioning grids are provided with information codes, and the arrangement mode of the information codes is a regular cross or an oblique cross.

Specifically, the positioning grid is square, and the arrangement mode of the information codes in the positioning grid can represent the direction of the image elements. Each dot matrix image element is divided into 4 positioning grids, each positioning grid is provided with 4 information codes, the arrangement mode of the positions of the 4 information codes adopts mixed coding of a positive cross and an oblique cross, and the arrangement mode of the positive cross and the oblique cross in each positioning grid is different from the arrangement mode of the positive cross and the oblique cross in the other 3 positioning grids.

Further, fig. 1 shows a dot matrix code primitive coding pattern adopted by the present invention, in which 13 is a location code, 15 is a virtual location line in the image processing process, indicated by a dotted line, and 12 is one of 4 positions of an information code, and different positions represent different coding values. 14 denotes a truly existing information code.

In fig. 1, the position codes are connected by horizontal and vertical dotted lines to form 4 × 4 position cells 11, and the position of the point code in each position cell can be 8, as shown in fig. 2. The numbers are 0 to 7 respectively. One of the information codes is selected and correspondingly coded as binary 000-111.

In the prior art, since the arrangement of the information codes is one of the above-mentioned 8 positions, there is a possibility that information code points continuously at the same position appear. For example, in a certain frame image, if the dots at position 0 are all in a certain column, a straight line arrangement is formed, which may affect the determination of the positioning code. For this purpose, the present invention arranges the information codes in two distributions, as shown in (a), (b) of fig. 3: the codes are respectively called as a positive cross and an oblique cross, and in the actual coding, the situation can be avoided by adopting the mixed coding of the positive cross and the oblique cross.

In addition, in one dot code cell, the direction of the dot code cell can be marked by using the right and oblique crosses as appropriate, so that it is not necessary to adopt a specific direction code. The positioning codes in the whole dot matrix code are more orderly, and the detection of the positioning codes is facilitated.

The regular and oblique cross arrangements of the invention obey two arrangement rules: firstly, in the horizontal, vertical or 45-degree oblique line direction, more than 3 continuous same crosses cannot appear, so that the possibility of forming straight lines by information code points is reduced, and the influence on the judgment of the positioning code is avoided as much as possible; and each image element is divided into 4 small areas, each small area is provided with 4 information codes, and the arrangement mode of the positive and oblique crosses of one small area is different from that of the other three small areas. For example, in the upper left corner cell, the upper left corner is defined as a positive cross, the rest is a diagonal cross, and the arrangement of information in the remaining three cells does not have this feature, refer to fig. 1.

step 1: acquiring a point code image;

and 2, step: carrying out image contour detection on the point code image to obtain barycentric coordinates of a code point contour;

The decoding process of the present invention is further described below with reference to specific embodiments of the present invention:

referring to fig. 4, fig. 4 is a frame image acquired from a camera. The pixels of the camera are 36 KB. The low-resolution camera has the advantages that the complexity of processing images by the dot matrix pen can be reduced, so that the calculated amount is reduced, the processing speed is increased, and the overall power consumption and cost are reduced. However, the camera has at least enough pixels to get no less than one image element of information.

Due to uneven illumination of the infrared light emitting tube of the camera, the collected dot code image has uneven brightness, and random noise caused by factors such as uneven paper surface and the like exists. For the captured image frame, preprocessing is performed, including performing smoothing filtering and histogram equalization on the image, wherein the smoothing filtering may be square-box filtering, mean filtering or gaussian filtering algorithm, and aims to eliminate random noise in the image, and the histogram equalization aims to enhance the contrast of the dot matrix image.

After preprocessing the image, it is necessary to detect the image contour of the acquired code point image, and then find the center of gravity of the code point contour as the actual position of the code point, as shown in fig. 5.

Because the coding method adopted by the invention, the positioning codes are arranged in a straight line, the number of code points on the straight line formed by the positioning codes is larger, the code points are uniformly arranged, and the information codes are sparsely scattered and arranged, so the interference caused by the detection of the positioning codes is less, and the positioning codes can be easily screened out. Further, as shown in fig. 6, using the coordinates of the code points as input quantities, the code points forming the linear arrangement can be found out by a linear detection method, for example, by Hough transformation.

As shown in fig. 7, according to the intersection point of the positioning straight lines, an image primitive including the central point of the image is found, then affine transformation is performed on the image primitive, three positioning points of affine transformation are 3 marking points in the figure, during affine transformation, the coordinate of the middle point is kept unchanged, the other two points are kept at equal intervals with the middle point, and the connecting lines of the other two points are perpendicularly intersected. This is also an image element for decoding, as an area included in the white box in fig. 8 (a).

The following describes the direction confirmation of image primitives and the decoding of decoded data in the primitives, based on the preliminary decoding of the image primitives.

Referring to fig. 1, firstly, 4 × 4 image primitives are divided into 4 2 × 2 cells, each of which has 4 information codes, and one cell having 1 even number and 3 odd numbers is found from the 4 cells as a direction flag cell (1 odd number and 3 even numbers can be set as the direction flag cell, but it is necessary to ensure that the set direction flag cell and other direction flag cells are the same as each otherThe arrangement of the information codes in the 3 cells is different and is at a specific position, such as the upper left corner or other positions, in the 4 positioning cells, and since the arrangement of the positive and oblique crosses in the corresponding position cells in different image elements is also fixed, it can be determined that each image element is located in the direction of the image), as shown in fig. 9. Since all positive crosses will decode to even numbers and all diagonal crosses will decode to odd numbers. In the previous embodiment, the cells in which this feature was found were

。

Since even cells are required to be on the upper left in encoding, the whole image needs to be rotated by 90 degrees clockwise, after rotation, the decoded value needs to be subtracted by 2, if the difference is less than zero, the value is added by 8, and after rotation, fig. 8 (b) is generated, and the generated value is shown in table 1 (consistent with the encoded value in fig. 2):

TABLE 1

6	1	4	5
				7	5	0	2
6	4	3	4
				1	2	2	3

And judging whether the image primitive is a complete primitive or not. From the above decoded data, it can be seen that the direction lattice (see table 2) appears in the upper left corner of the primitive size area, so that the above decoded data can be judged as a complete dot matrix code image primitive. Thus, the data can be directly decoded without performing a splicing operation.

TABLE 2

6	1
		7	5

After rotation, the encoded value is right-shifted by one bit, i.e. the encoded form of fig. 2 is transformed into the encoded form of fig. 3. The above codes form a 4 x 4 array dots [4] [4], with the resulting values shown in Table 3:

TABLE 3

3	0	2	2
				3	2	0	1
3	2	1	2
				0	1	1	1

When encoding, if the coordinate position is specified: x, y, and other information content encodes info1 and info 2. In this embodiment, info1 indicates a page number, info2 indicates a content range, and info1 or info2 may be set to other contents, dots [0] [0] indicates a dots array element [0,0], and dots [1] [0] indicates a dots array element [1,0 ]. They have the following relationship with dots [4] [4 ]:

x=dots[0][0]+4* dots[1][0]+16* dots[2][0]+64* dots[3][0]

y=dots[0][1]+4* dots[1][1]+16* dots[2][1]+64* dots[3][1]

info1= dots[0][2]+4* dots[1][2]+16* dots[2][2]+64* dots[3][2]

info2= dots[0][3]+4* dots[1][3]+16* dots[2][3]+64* dots[3][3]

and finally, correcting the coordinates according to the difference value between the pen point coordinates and the central coordinates of the image elements and the rotation angle, and obtaining the final coordinates of the dot-matrix pen after correction.

In one embodiment, if the orientation locator grid is not in the upper left corner after rotation according to the orientation locator grid, such as in the form of table 4:

TABLE 4

6	4	3	4
				1	2	2	3
6	1	4	5
				7	5	0	2

It is indicated that the selected area spans the upper and lower image primitives, so the data of the primitives needs to be stitched. According to the encoding rule, the decoding form at this time is:

x=dots[2][0]+4* dots[3][0]+16* dots[0][0]+64* dots[1][0]

y=dots[2][1]+4* dots[3][1]+16* dots[0][1]+64* dots[1][1]

info1= dots[2][2]+4* dots[3][2]+16* dots[0][2]+64* dots[1][2]

info2= dots[2][3]+4* dots[3][3]+16* dots[0][3]+64* dots[1][3]

the center of the image primitive also correspondingly becomes the lower edge midpoint of the full primitive size region (instead of the original center of the full primitive size region), but still is the lower right corner of the bin. Due to the fact thatx, yRepresenting the coordinates of the image elements, are successively coded, between two adjacent elements, the lower element being larger than the upper elementyA value greater than 1, andxthe value remains unchanged. The decoded y value is likely to have a carry here, i.e.:

when dots [2] [2] = dots [3] [2] =0, the value of dots needs to be increased by 16. Similar processing is also performed when the positioning grid is at the upper right corner and the lower right corner respectively.

The invention also provides a point code decoding system, which comprises:

The embodiment of the present invention further provides an electronic device, which includes a bus, a transceiver, a memory, a processor, and a computer program stored in the memory and capable of running on the processor, where the transceiver, the memory, and the processor are connected via the bus, and when the computer program is executed by the processor, the processes of the embodiment of the point code decoding method are implemented, and the same technical effect can be achieved, and therefore, details are not described here to avoid repetition.

The above description is only an embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of changes or substitutions within the technical scope of the present invention, and the present invention shall be covered by the claims. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.

Claims

1. A dot matrix code, comprising:

2. A method for decoding a point code, comprising:

step 1: acquiring a point code image;

step 2: carrying out image contour detection on the point code image to obtain barycentric coordinates of a code point contour;

and 3, step 3: extracting a target area with the same size as the image element in the point code image by using the barycentric coordinates;

3. A point code decoding system, comprising:

4. An electronic device comprising a bus, a transceiver, a memory, a processor and a computer program stored on the memory and executable on the processor, the transceiver, the memory and the processor being connected via the bus, characterized in that the computer program realizes the steps of a method of decoding point codes as claimed in claim 2 when executed by the processor.