Point cloud pattern including reference pattern for decoding, method for encoding same, and method for decoding same

Abstract

The present invention may comprise: a point cloud pattern including a reference pattern for decoding, wherein the point cloud pattern includes a plurality of reference dots indicating position coordinates; and the reference pattern in which vertical dotted lines of different lengths indicating directions are arranged at predetermined intervals in the horizontal direction, and a point is formed between the vertical dotted lines of different lengths.

Description

Point cloud pattern formed as a reference pattern for decoding, encoding method thereof, and decoding method thereof

[0001] The present invention relates to a point cloud pattern formed with a reference pattern for decoding, an encoding method thereof, and a decoding method thereof, and more specifically, to a point cloud pattern formed with a reference pattern for decoding, an encoding method thereof, and a decoding method thereof, which enable the point cloud pattern to be photographed from any direction, and thereby extract and provide position coordinates indicated by reference dots constituting the point cloud pattern by recognizing the direction through the reference pattern.

[0002] A barcode is a code or system that represents information using a pattern of black and white bars of varying widths. Depending on their width, the black and white bars are converted into one or more binary bits (0 or 1), and these combinations represent ASCII characters. However, they have the disadvantage of being able to express only about 20 digits of information.

[0003] As mentioned above, the QR code (Quick Response code) was proposed to address the problem of barcodes being limited to representing only about 20 digits of information. A QR code is a two-dimensional code that encodes a variety of information in a rectangular grid pattern, capable of containing significantly more information than conventional barcodes.

[0004] While conventional one-dimensional codes can only store numeric information of about 20 characters, the QR code can store up to 7,089 numeric characters, up to 4,296 ASCII characters, up to 2,953 bytes of 8-bit binary data, and up to 1,817 Chinese characters. It has a fast recognition speed, recognition rate, and restoration rate, and is being used more widely than the previously widely used barcode.

[0005] However, QR codes can contain more information than previous barcodes. These dots can be exploited to embed malware or malicious website addresses into QR codes. Scanning a QR code containing such malicious information with a reader without due suspicion can expose you to malware or redirect you to a malicious website. Therefore, caution is advised when using QR codes not provided by verified sources or companies.

[0006] As prior art documents related to the background technology of the present invention, there are Korean Patent No. 10-2179513 (announced on November 16, 2020) entitled “QR code printing method for output material using an image forming device, and QR code printing system for output material,” and Korean Patent No. 10-1420361 (announced on July 21, 2014) entitled “QR code authentication system and method and computer-readable recording medium recording a program for executing the same.”

[0007] The present invention aims to provide a point cloud pattern in which a reference pattern for decoding is formed, a method for encoding the same, and a method for decoding the same, which can extract and provide position coordinates indicated by reference dots constituting the point cloud pattern by recognizing the direction through the reference pattern regardless of the direction in which the point cloud pattern is photographed.

[0008]

[0009] The purposes of the invention are not limited to those mentioned above, and other purposes and advantages of the invention not mentioned above can be understood through the following description and will be more clearly understood through the embodiments of the invention. Furthermore, it will be readily apparent that the purposes and advantages of the invention can be realized by the means and combinations thereof set forth in the claims.

[0010] A point cloud pattern formed as a reference pattern for decoding to achieve this purpose may include a point cloud pattern composed of a plurality of reference dots indicating position coordinates and a reference pattern in which vertical dotted lines of different lengths indicating directions are formed at specific intervals in the horizontal direction, and a point is formed between the vertical dotted lines of different lengths.

[0011] In one embodiment, the reference pattern may be formed by vertical dotted lines having a first length, a second length longer by a specific length than the first length, and a third length longer by a specific length than the second length, spaced apart in the horizontal direction by a specific interval.

[0012] In one embodiment, the reference pattern may include forming a first vertical dotted line of length indicating one of an upward direction and a downward direction and a third vertical dotted line of length indicating the other direction.

[0013] In addition, a method for encoding a point cloud pattern in which a reference pattern for decoding is formed to achieve this purpose includes a step of forming a point cloud pattern composed of a plurality of reference dots indicating position coordinates, a step of forming vertical dotted lines of different lengths indicating directions on the point cloud pattern by horizontally spacing them apart by a specific interval, and a step of forming a reference pattern by placing dots between the vertical dotted lines of different lengths.

[0014] In one embodiment, the step of forming vertical dotted lines of different lengths indicating directions on the point cloud pattern by spacing them apart in the horizontal direction by a specific interval may include the step of forming vertical dotted lines of a first length, a second length longer by a specific length than the first length, and a third length longer by a specific length than the second length by spacing them apart in the horizontal direction by a specific interval.

[0015] In one embodiment, the step of forming vertical dotted lines of different lengths spaced apart from each other in the horizontal direction by a specific interval may include the step of forming a vertical dotted line of a first length indicating one of the upward and downward directions and a vertical dotted line of a third length indicating the other direction.

[0016] In addition, a method for decoding a point cloud pattern in which a reference pattern is formed to achieve this purpose may include a step of scanning a point cloud pattern in which a reference pattern for decoding is formed, a step of detecting a point located in the middle of a reference pattern on the point cloud pattern, a step of detecting another point centered on the point located in the middle, a step of connecting the other points to create a specific area and then determining the upper and lower portions of the specific area, and a step of determining and correcting the upper and lower portions of the specific area and then decoding the point cloud pattern of the specific area.

[0017] In one embodiment, the step of detecting another point centered on the point located in the middle may include the step of calculating a distance between other points centered on the point located in the middle, detecting another point with a close distance as a region setting dot, and the step of detecting a vertical dotted line in an upward or downward direction based on the another point with a close distance, and detecting a point close to the end of the vertical dotted line in the upward or downward direction as a region setting dot.

[0018] In one embodiment, the step of determining the upper and lower sides of the specific area and then decoding the point cloud pattern of the specific area may include the step of comparing the length between the vertical dotted line in the upper direction and the vertical dotted line in the lower direction, and if the vertical dotted line in the upper direction is longer than the vertical dotted line in the lower direction, rotating the specific area so that the lower direction becomes the upper direction and decoding the point cloud pattern of the specific area.

[0019] According to the present invention as described above, there is an advantage in that no matter which direction a point cloud pattern is photographed from, the direction can be recognized through a reference pattern, and the position coordinates indicated by the reference dots constituting the point cloud pattern can be extracted and provided.

[0020] FIG. 1 is a drawing for explaining a point cloud pattern formed as a reference pattern for decoding according to one embodiment of the present invention.

[0021] FIG. 2 is a flowchart illustrating another embodiment of a method for forming a reference pattern for decoding a point cloud pattern according to one embodiment of the present invention.

[0022] FIG. 3 is a flowchart illustrating another embodiment of a point cloud pattern decoding method in which a reference pattern for decoding is formed according to the present invention.

[0023] FIG. 4 is a flowchart illustrating another embodiment of a point cloud pattern decoding method in which a reference pattern for decoding is formed according to the present invention.

[0024] FIG. 5 is a flowchart illustrating another embodiment of a point cloud pattern decoding method in which a reference pattern for decoding is formed according to the present invention.

[0025] Figures 6 and 7 are exemplary diagrams for explaining a point cloud pattern decoding process in which a reference pattern for decoding according to the present invention is formed.

[0026] The above-described objects, features, and advantages will be described in detail below with reference to the attached drawings, so that those skilled in the art can easily practice the technical ideas of the present invention. In describing the present invention, if it is determined that a detailed description of known technologies related to the present invention may unnecessarily obscure the gist of the present invention, a detailed description thereof will be omitted. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. In the drawings, the same reference numerals are used to indicate the same or similar components.

[0027]

[0028] FIG. 1 is a drawing for explaining a point cloud pattern formed as a reference pattern for decoding according to one embodiment of the present invention.

[0029] Referring to FIG. 1, a point cloud pattern formed as a reference pattern for decoding may include a point cloud pattern (100) composed of a plurality of reference dots indicating position coordinates and a reference pattern (200) in which vertical dotted lines of different lengths indicating directions are formed at specific intervals in the horizontal direction, and dots are formed between the vertical dotted lines of different lengths.

[0030] Each of the plurality of reference dots constituting the point cloud pattern (100) can indicate a specific position coordinate on a predetermined global coordinate. For example, if the global coordinate is from (0, 0) to (100, 100), the plurality of reference dots can be determined to have any one position coordinate between (0, 0) and (100, 100) depending on their positions.

[0031] When the decoding device decodes the above point cloud pattern (100), if the point cloud pattern (100) is photographed in the forward direction during the process of scanning the point cloud pattern (100), the position coordinates of each reference dot constituting the point cloud pattern (100) can be recognized. However, when the decoding device decodes the above point cloud pattern, if the point cloud pattern (100) is photographed in the reverse direction, sideways direction, etc. instead of the forward direction during the process of scanning the point cloud pattern, there is a problem in that the shooting direction cannot be recognized, and thus the position coordinates of each reference dot constituting the point cloud pattern cannot be recognized.

[0032] In order to solve these problems, the present invention forms a reference pattern (200) indicating a direction in a state where a point cloud pattern (100) is formed, so that no matter from which direction the point cloud pattern (100) is photographed, the shooting direction can be recognized through the reference pattern (200), and the position coordinates indicated by the reference dot constituting the point cloud pattern can be extracted and provided.

[0033] A reference pattern (200) for this purpose is formed by vertical dotted lines of different lengths indicating directions being spaced apart in the horizontal direction by a specific interval, and dots are formed between the vertical dotted lines of different lengths.

[0034] In one embodiment, the vertical dotted line of the reference pattern (200) may be formed by a first vertical line segment (210) of a first length, a second vertical line segment (220) of a second length that is a specific length longer than the first length, and a third vertical line segment (230) of a third length that is a specific length longer than the second length, spaced apart from each other by a specific interval in the horizontal direction.

[0035] Additionally, each of the first vertical line segment (210), the second vertical line segment (220), and the third vertical line segment (230) may be formed spaced apart from each other by a specific interval, and a point may be formed between the first vertical line segment (210), the second vertical line segment (220), and the third vertical line segment.

[0036] As described above, the reason why the lengths of the first vertical line segment (210), the second vertical line segment (220), and the third vertical line segment (230) are implemented differently is that the vertical line segment with a shorter length can indicate one of the upward and downward directions of the entire coordinates, and the vertical line segment with a longer length can indicate the remaining direction among the upward and downward directions.

[0037] Accordingly, when the decoding device scans the point cloud pattern (100) to generate a point cloud pattern image, it detects a point located in the middle of the point cloud pattern image, detects other points based on the point located in the middle, and then connects the other points to enable detection of a specific area.

[0038]

[0039] FIG. 2 is a flowchart illustrating another embodiment of a method for forming a reference pattern for decoding a point cloud pattern according to one embodiment of the present invention.

[0040] Referring to FIG. 2, in step S210, the encoding device forms a point cloud pattern composed of a plurality of reference dots indicating position coordinates.

[0041] Each of the multiple reference dots that constitute a point cloud pattern can indicate a specific location coordinate within a predetermined global coordinate system. For example, if the global coordinate system is (0, 0) to (100, 100), the multiple reference dots can be determined to have any location coordinate within the range (0, 0) to (100, 100) depending on their location.

[0042] In step S220, the encoding device forms vertical dotted lines of different lengths indicating directions on the point cloud pattern by spacing them apart in the horizontal direction at a specific interval.

[0043] In one embodiment for step S220, the encoding device can form vertical dotted lines of a first length, a second length longer by a specific length than the first length, and a third length longer by a specific length than the second length, spaced apart in the horizontal direction by a specific interval.

[0044] As described above, the reason for implementing the lengths of each vertical line segment constituting the vertical dotted line differently is that a vertical line segment with a shorter length can indicate one of the upward and downward directions of the entire coordinate system, and a vertical line segment with a longer length can indicate the remaining direction among the upward and downward directions.

[0045] The reason why the lengths of each vertical line segment forming the vertical dotted line are implemented differently is that a vertical line segment with a shorter length can point in one of the upward and downward directions of the overall coordinates, and a vertical line segment with a longer length can point in the other of the upward and downward directions.

[0046] Accordingly, when the decoding device scans the point cloud pattern (100) to generate a point cloud pattern image, it detects a point located in the middle of the point cloud pattern image, detects other points based on the point located in the middle, and then connects the other points to enable detection of a specific area.

[0047]

[0048] Fig. 3 is a flowchart illustrating another embodiment of a point cloud pattern decoding method in which a reference pattern for decoding is formed according to the present invention. Fig. 3 relates to an embodiment of searching for a reference pattern in a point cloud pattern.

[0049] Referring to FIG. 3, the decoding device scans a point cloud pattern in which a reference pattern for decoding is formed (step S310).

[0050] The decoding device scans the point cloud pattern and then finds multiple lines (step S320).

[0051] The decoding device attempts location clustering using information on the start and end points of each extracted line (step S330). This clusters lines that are close to each other based on the distance between the start and end points of the lines.

[0052] In one embodiment, the decoding device verifies that each line can belong to one of the pre-generated clusters and, based on the verification result, adds the line to an existing cluster or creates a new cluster and adds the line to the new cluster.

[0053] In the above embodiment, the decoding device adds the line to the existing cluster if both the start point and the end point of the line are within the tolerance range, or if the start point of the line is within the wider tolerance range (1.3 times) and the end point is within the basic tolerance range, or if the start point is within the basic tolerance range and the end point of the line is within the wider tolerance range (1.3 times).

[0054] In the above process, since only the information of the start and end points of the line is used for a simple comparison, the decoding device repeats the above process once more after swapping the start and end points when the line can belong to one of the pre-generated clusters.

[0055] The decoding device clusters the lines that have completed clustering by their gradient values, and then leaves only the cluster with the largest number of overlaps within the gradient cluster as the representative cluster.

[0056] The decoding device selects a representative line from each cluster and regroups the lines based on the slope (step S340).

[0057] To achieve this, the decoder extracts the line that overlaps most with other lines in the cluster as a representative line. At this time, the decoder double-checks the starting and ending points by swapping them to account for cases where the starting and ending points of the lines are at different locations.

[0058] Afterwards, the decoder re-clusters the data based on the slope of each representative line. That is, the decoder groups lines with similar slopes into the same cluster.

[0059] As described above, the decoding device selects the largest cluster among the clusters formed by the gradients and leaves only that cluster.

[0060]

[0061] Fig. 4 is a flowchart illustrating another embodiment of a point cloud pattern decoding method in which a reference pattern for decoding is formed according to the present invention. Fig. 4 relates to an embodiment of finding corner points for perspective transformation in a point cloud pattern.

[0062] Referring to FIG. 4, the decoding device scans a point cloud pattern in which a reference pattern for decoding is formed (step S410).

[0063] The decoding device extracts multiple points from the point cloud pattern and searches for the point closest to the center of the screen (step S420).

[0064] In one embodiment of step S420, the decoding device extracts multiple points from the image using SimpleBlobDetector, calculates the distance from the Cross-Point located at the center of the screen to each point, and selects the closest point. This point becomes the first reference point for perspective transformation.

[0065] The decoding device finds a point on the reference line closest to the first reference point of the perspective transformation, and then makes this point the second reference point of the perspective transformation (step S430).

[0066] In one embodiment of step S430, the decoding device calculates the distance between the first reference point of the perspective transformation and the points of the outer reference lines, finds one point with a close distance, and expands it to set it as the reference point. This point becomes the second reference point of the perspective transformation.

[0067] The decoding device sets points on other reference lines located outside the second reference point of the perspective transformation as extended reference points (step S440). In this case, the outer reference lines refer to lines located further outside the reference line.

[0068] In one embodiment of step S440, the decoding device selects one point closest to the second reference point from each outer reference line and sets these points as extended reference points. These extended reference points serve as the basis for calculating corner points for perspective transformation.

[0069] The decoding device selects a perspective transformation corner point in the line segment direction from the extended reference point (step S450).

[0070] In one embodiment of step S450, the decoding device selects a corner point for perspective transformation starting from the extended reference point. To this end, the decoding device searches for the corner point of the perspective transformation by crossing points a specified number of times from the extended reference point toward the start and end points of the line segment. For example, the second or third point may be selected, and these points may be selected from points arranged parallel to each other along the line. Since one point is selected for each extended reference point in the above process, a total of four corner points are determined in this process.

[0071] The decoding device aligns the four corner points for perspective transformation (step S460). For perspective transformation, the four corner points must be arranged in the correct order. To achieve this, each corner point is aligned with the direction in which the reference lines are perpendicular. This generally means that for perspective transformation of a rectangular area, the corner points must be arranged in a certain order.

[0072] Therefore, the decoding device adjusts the order of the selected corner points so that they can be correctly converted in the image. The corner points can be arranged in the following order on the screen: top left, top right, bottom right, and bottom left.

[0073] The decoding device performs perspective transformation using four corner points (step S450).

[0074]

[0075] Figure 5 is a flowchart illustrating another embodiment of a point cloud pattern decoding method in which a reference pattern for decoding is formed according to the present invention. Figure 5 describes a process for determining image flipping.

[0076] Referring to FIG. 5, the decoding device sets a basic length of a reference pattern and then sets different dash lengths using the basic length (step S510).

[0077] For example, if L is the base length, then the vertical dashed line A is set to dash length A with a length that is 50% longer than the base length L, the vertical dashed line B is set to dash length B with a length that is 50% longer than the base length L, and the vertical dashed line C is set to dash length C with the added length. In this way, three different dash lengths are set. These vertical dashed lines are used as a reference for comparing the lengths of lines extracted from the image later.

[0078] The decoding device extracts a vertical dotted line from an image to which perspective transformation has been applied (step S520).

[0079] In one embodiment of step S520, the decoding device sets a Region of Interest (ROI) to extract only the area where the central reference line exists in the image to which perspective transformation has been applied. The ROI is set by defining the area of ​​the reference line located at the center of the image to which perspective transformation has been applied and performing operations only within this area. For example, the area of ​​the central reference line is set and the area is cropped to create a new image.

[0080] Afterwards, the decoding device can use a line detection technique (e.g., Hough Line Transform) to find only the line region in the extracted ROI image. After extracting the line region, the length of the vertical dotted line is measured based on this.

[0081] The decoding device determines whether the image is flipped by determining whether it corresponds to a predetermined reference pattern using the length of the vertical dotted line (step S530).

[0082] In one embodiment for step S530, the decoding device can measure the length by obtaining the distance between the end points of the extracted vertical dotted line, and determine whether the image is flipped by using the length of the vertical points to determine whether it corresponds to a predetermined reference pattern.

[0083]

[0084] FIG. 6 and FIG. 7 are exemplary diagrams for explaining a point cloud pattern decoding process in which a reference pattern for decoding according to the present invention is formed. Referring to FIG. 6 and FIG. 7, the decoding device extracts a plurality of points and searches for the point (400) closest to the center of the screen.

[0085] At this time, the decoding device extracts multiple points from the image using SimpleBlobDetector, calculates the distance from the Cross-Point located at the center of the screen to each point, and selects the closest point. This point (400) becomes the first reference point for perspective transformation.

[0086] The decoding device finds a point (410) on the reference line closest to the first reference point of perspective transformation, and then makes this point the second reference point of perspective transformation (step S430).

[0087] In one embodiment, the decoding device can calculate the distance between other points centered around a point (410) located in the middle, and detect other points (410) with close distances as area setting dots.

[0088] After that, the decoding device can detect a vertical dotted line in the upper or lower direction based on another point (410) that is close to the distance, and can detect a point (420, 430) close to the end of the vertical dotted line in the upper or lower direction as an area reference point.

[0089] The decoding device connects the area reference points to create a specific area (500) as shown in Fig. 7 and determines the upper and lower parts of the specific area (500).

[0090] That is, the decoding device detects a vertical dotted line in an upward or downward direction based on another point that is close to the center, compares the length between the vertical dotted lines in the upward and downward directions, and if the vertical dotted line in the upward direction is longer than the vertical dotted line in the downward direction, the downward direction can be determined as the upward direction of the point cloud pattern.

[0091] The decoding device determines the upper and lower sides of a specific area (500) and corrects them, and then decodes the point cloud pattern of the specific area (500).

[0092]

[0093] While described with reference to limited embodiments and drawings, the present invention is not limited to the above-described embodiments, and various modifications and variations are possible based on this disclosure by those skilled in the art. Accordingly, the scope of the present invention should be understood solely by the scope of the claims set forth below, and all equivalent or equivalent modifications thereof are deemed to fall within the scope of the present invention.

Claims

1. A point cloud pattern consisting of multiple reference dots indicating position coordinates; and A reference pattern characterized in that vertical dotted lines of different lengths indicating directions are formed at specific intervals in the horizontal direction, and dots are formed between the vertical dotted lines of different lengths. Point cloud pattern formed as a reference pattern for decoding 2. In paragraph 1, The above reference pattern is It is characterized in that vertical dotted lines of a first length, a second length longer by a specific length than the first length, and a third length longer by a specific length than the second length are formed at a specific interval in the horizontal direction. A point cloud pattern that forms a reference pattern for decoding.

3. In paragraph 1, The above reference pattern is characterized by comprising the step of forming a first vertical dotted line of length indicating one of the upward and downward directions and a third vertical dotted line of length indicating the other direction. A method for forming a reference pattern for decoding point cloud patterns.

4. A step of forming a point cloud pattern composed of a plurality of reference dots indicating position coordinates; A step of forming vertical dotted lines of different lengths indicating directions on the above point cloud pattern by spacing them out at a specific interval in the horizontal direction; and characterized by including a step of forming a reference pattern by placing points between vertical dotted lines of different lengths. A method for encoding point cloud patterns in which a reference pattern for decoding is formed.

5. In paragraph 4, The step of forming vertical dotted lines of different lengths indicating directions on the above point cloud pattern by spacing them out at a specific interval in the horizontal direction It is characterized by including a step of forming vertical dotted lines of a first length, a second length longer by a specific length than the first length, and a third length longer by a specific length than the second length by a specific distance in the horizontal direction. A method for forming a reference pattern for decoding point cloud patterns.

6. In paragraph 5, The step of forming the vertical dotted lines of different lengths by spacing them out at a specific interval in the horizontal direction is as follows: characterized by comprising the step of forming a first vertical dotted line of length indicating one of the upward and downward directions and a third vertical dotted line of length indicating the other direction. A method for forming a reference pattern for decoding point cloud patterns.

7. A step of scanning a point cloud pattern in which a reference pattern for decoding is formed; A step of detecting a point located in the middle of a reference pattern on the above point cloud pattern; A step of detecting other points centered on the point located in the middle above; A step of connecting the above different points to create a specific area and then determining the upper and lower parts of the specific area; and It is characterized by including a step of decoding the point cloud pattern of the specific area after determining and correcting the upper and lower portions of the specific area. A method for decoding a point cloud pattern in which a reference pattern for decoding is formed.

8. In paragraph 7, The step of detecting other points centered on the point located in the middle above is A step of calculating the distance between other points centered on the point located in the middle, and detecting other points with close distances as area setting dots; and It is characterized by including a step of detecting a vertical dotted line in an upward or downward direction based on another point close to the distance, and detecting a point close to the end of the vertical dotted line in the upward or downward direction as an area setting dot. A method for decoding a point cloud pattern in which a reference pattern for decoding is formed.

9. In paragraph 7, The step of decoding the point cloud pattern of the specific area after judging and correcting the upper and lower portions of the specific area is as follows. A step of comparing the length between the vertical dotted line in the upper direction and the vertical dotted line in the lower direction, and if the vertical dotted line in the upper direction is longer than the vertical dotted line in the lower direction, decoding the point cloud pattern of the specific area by rotating and correcting the specific area so that the lower direction becomes the upper direction. A method for decoding a point cloud pattern in which a reference pattern for decoding is formed.

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