A blind writing navigation method based on space mapping and dynamic optimization

Abstract

The application discloses a blind writing navigation method based on space mapping and dynamic optimization and belongs to the technical field of blind writing navigation, and comprises the following steps: writing a target Chinese character and determining a coordinate sequence of key points of the target Chinese character; performing key point distribution analysis on the coordinate sequence of the key points of the target Chinese character and performing key point optimization; determining relative position coordinates of a pen nib in a writing board by establishing a writing coordinate system on the writing board; determining the position of an upper-left point of the target Chinese character in a virtual mapping graph; mapping the optimized coordinates of the key points of the target Chinese character and the relative position coordinates of the pen nib to the virtual mapping graph to obtain a writing track and a pen nib position on the virtual mapping graph; calculating a navigation direction through a dynamic optimization algorithm, generating voice navigation information according to the navigation direction and completing blind writing navigation. The application solves the problems of inaccurate positioning and inflexible path planning of the existing blind writing navigation system.

Description

Technical Field

[0001] This invention belongs to the field of writing navigation technology for the blind, specifically relating to a writing navigation method for the blind based on spatial mapping and dynamic optimization. Background Technology

[0002] With the continuous development of technology, the technologies assisting blind people in their daily lives are also constantly improving. Braille writing and navigation systems, as an important technology in this field, aim to provide blind people with a convenient and efficient way to write and navigate. However, existing braille writing and navigation systems often suffer from problems such as inaccurate positioning and inflexible route planning, failing to fully meet the actual needs of blind people. Furthermore, blind people may misunderstand navigation directions based on voice prompts.

[0003] This invention optimizes the writing path through spatial mapping and proposes a dynamic optimization algorithm based on perception-cognition theory to optimize the calculation of navigation direction and accurately guide blind people in writing. Summary of the Invention

[0004] This invention provides a method for blind writing navigation based on spatial mapping and dynamic optimization, which solves the problems of inaccurate positioning and inflexible path planning in existing blind writing navigation systems.

[0005] To solve the above-mentioned technical problems, the technical solution of the present invention is: a method for blind writing navigation based on spatial mapping and dynamic optimization, comprising the following steps:

[0006] S1. Write the target Chinese character using a writing board and determine the coordinate sequence of the key points of the target Chinese character;

[0007] S2. Analyze the distribution of key points in the coordinate sequence of key points of the target Chinese character and optimize the key points to obtain the optimized coordinates of the key points of the target Chinese character.

[0008] S3. By establishing a writing coordinate system on the writing board, determine the relative position coordinates of the pen tip on the writing board;

[0009] S4. Construct a virtual mapping graph and establish a coordinate system for the mapping graph to determine the position of the top-left point of the target Chinese character in the virtual mapping graph;

[0010] S5. Based on the position of the top left point of the target Chinese character in the virtual mapping, map the optimized coordinates of the key points of the target Chinese character and the relative position coordinates of the pen tip to the virtual mapping to obtain the writing trajectory and pen tip position on the virtual mapping.

[0011] S6. Based on the writing trajectory and pen tip position, the navigation direction is calculated through a dynamic optimization algorithm, and voice navigation information is generated according to the navigation direction to complete the writing navigation for the blind.

[0012] Furthermore, in step S1, the coordinate sequence of the key points of the target Chinese character is stored separately according to each stroke of the target Chinese character.

[0013] Furthermore, the specific coordinates of step S2 are:

[0014] S21. Analyze the distribution of the coordinate sequence of key points of the target Chinese character and determine the areas where the key points are unevenly distributed;

[0015] S22. Identify sub-regions with fewer key points based on the first threshold, and insert new key points in the sub-regions with fewer key points;

[0016] S23. Identify redundant key points that are too close together in the region based on the second threshold, remove the redundant key points, and obtain the optimized coordinates of the target Chinese character key points.

[0017] Furthermore, the specific steps for determining the uneven distribution of key points in step S21 are as follows: calculate the distance between key points and determine the maximum distance d between key points. max and the minimum distance d between key points min Determine d max Is it greater than 2d? min If so, the key points are unevenly distributed; otherwise, the key points are evenly distributed.

[0018] Furthermore, the optimized coordinates of the target Chinese character key points in step S2 are (x... i n ,y i n ), where x i n The x-coordinate of the i-th key point of the n-th stroke of the target Chinese character is represented by y. i n The vertical coordinate represents the ordinate of the i-th key point of the n-th stroke of the target Chinese character.

[0019] Furthermore, in step S2, the relative position coordinates of the pen tip on the writing board are (bx) t by t ), where bx t The x-coordinate representing the relative position of the pen tip on the writing board, by t The vertical coordinate represents the relative position of the pen tip on the writing board.

[0020] Furthermore, in step S3, the position of the top left point of the target Chinese character in the virtual mapping is (sx, sy), where sx represents the horizontal coordinate of the top left point of the target Chinese character in the virtual mapping, and sy represents the vertical coordinate of the top left point of the target Chinese character in the virtual mapping.

[0021] Furthermore, the aspect ratio of the virtual mapping image is the same as that of the writing board;

[0022] The width of the writing board is W board The height of the writing board is H. board The width of the virtual mapping graph is W. map The height of the virtual mapping graph is H. map .

[0023] Furthermore, in step S5, the writing trajectory is represented as the i-th key point of the n-th stroke on the virtual mapping map. The set of points, wherein the pen tip position is represented as (px) t ,py t );

[0024] The expressions for the writing trajectory and pen tip position are:

[0025]

[0026]

[0027]

[0028]

[0029] in, This represents the x-coordinate of the i-th key point of the n-th stroke on the virtual mapping map. The length represents the ordinate of the i-th key point of the n-th stroke on the virtual mapping graph. ch Represents the size parameter, px t This represents the x-coordinate of the pen tip mapped onto the virtual map, in Python. t This represents the vertical coordinate after the pen tip is mapped onto the virtual mapping graph.

[0030] Further, the specific steps of step S6 are as follows: take the midpoint between the pen tip position coordinates and the coordinates of the previous stroke key point in the writing trajectory as the starting point coordinates of the navigation direction, take the current stroke key point coordinates as the ending point of the navigation direction, fine-tune the navigation direction through dynamic parameter a, generate voice navigation information based on the adjusted navigation direction, and complete the blind writing navigation.

[0031] The expression for calculating the navigation direction in step S6 is as follows:

[0032]

[0033]

[0034]

[0035] Where, x at The x-coordinate of the starting position of the navigation direction, y at The ordinate represents the starting position of the navigation direction, where 'a' represents a dynamic parameter. write Indicates the direction in which the text is written. write (·) represents the formula for calculating direction. This represents the x-coordinate of the (i+1)th key point of the nth stroke on the virtual mapping graph. This represents the ordinate of the (i+1)th key point of the nth stroke on the virtual mapping.

[0036] The beneficial effects of the present invention are: (1) By using the coordinate information on the virtual mapping map, the coordinates of the writing path and the coordinates of the pen tip on the writing board are simultaneously mapped onto the same mapping map, thereby achieving precise control of the writing process, which can help build a flexible path planning and navigation scheme, enabling the blind writing navigation system to adapt to different writing styles and speeds, and improving the user's writing experience;

[0037] (2) By optimizing the path of the key points of the target Chinese character, the writing path is made smoother and easier to understand, which solves the problems of uneven distribution of key points of strokes and complex stroke shapes, and improves the accuracy and fluency of blind writing.

[0038] (3) Through spatial coordinate mapping, the blind writing navigation system can easily adjust the size and position of the written characters to meet the personalized needs of different blind users for writing effect;

[0039] (4) The present invention improves the flexibility, accuracy and effectiveness of the system, reduces the extra data operations required to adjust the size and position of the written text, and reduces maintenance costs.

[0040] (5) Based on the dynamic optimization algorithm, the deviation caused by blind people understanding the navigation direction based on voice prompts is reduced, and the actual navigation direction is adjusted to be more consistent with the expected path direction, thereby reducing the difference between the perceived direction and the actual direction and improving the accuracy of the blind writing navigation system. Attached Figure Description

[0041] Figure 1 This is a flowchart of the blind writing navigation method based on spatial mapping and dynamic optimization according to the present invention.

[0042] Figure 2 This is a schematic diagram illustrating the key point optimization of the present invention.

[0043] Figure 3 This is a schematic diagram illustrating the calculation of navigation direction using a dynamic optimization algorithm according to the present invention. Detailed Implementation

[0044] Those skilled in the art will recognize that the embodiments described herein are intended to help the reader understand the principles of the invention, and should be understood that the scope of protection of the invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific modifications and combinations based on the technical teachings disclosed in this invention without departing from the spirit of the invention, and these modifications and combinations are still within the scope of protection of this invention.

[0045] Example

[0046] like Figure 1 As shown, this invention provides a method for blind writing navigation based on spatial mapping and dynamic optimization, comprising the following steps:

[0047] S1. Write the target Chinese character using a writing board and determine the coordinate sequence of the key points of the target Chinese character;

[0048] S2. Analyze the distribution of key points in the coordinate sequence of key points of the target Chinese character and optimize the key points to obtain the optimized coordinates of the key points of the target Chinese character.

[0049] S3. By establishing a writing coordinate system on the writing board, determine the relative position coordinates of the pen tip on the writing board;

[0050] S4. Construct a virtual mapping graph and establish a coordinate system for the mapping graph to determine the position of the top-left point of the target Chinese character in the virtual mapping graph;

[0051] S5. Based on the position of the top left point of the target Chinese character in the virtual mapping, map the optimized coordinates of the key points of the target Chinese character and the relative position coordinates of the pen tip to the virtual mapping to obtain the writing trajectory and pen tip position on the virtual mapping.

[0052] S6. Based on the writing trajectory and pen tip position, the navigation direction is calculated through a dynamic optimization algorithm, and voice navigation information is generated according to the navigation direction to complete the writing navigation for the blind.

[0053] In step S1, the coordinate sequence of the key points of the target Chinese character is stored separately according to each stroke of the target Chinese character.

[0054] The specific coordinates of step S2 are:

[0055] S21. Analyze the distribution of the coordinate sequence of key points of the target Chinese character and determine the areas where the key points are unevenly distributed;

[0056] S22. Identify sub-regions with fewer key points based on the first threshold, and insert new key points in the sub-regions with fewer key points;

[0057] S23, identifying redundant key points that are too close in the region according to a second threshold, and removing the redundant key points to obtain optimized coordinates of the target Chinese character key points.

[0058] The specific step of determining uneven key point distribution in said step S21 is: calculating distances between key points, and determining the maximum distance d between key points max and the minimum distance d between key points min , determining whether d max is greater than 2d min , if yes, the key points are unevenly distributed; otherwise, the key points are evenly distributed.

[0059] As shown in Figure 2 , from left to right are the original coordinate sequence of key points, the point insertion process and the optimized key points of the Chinese character "An".

[0060] In said step S2, the optimized coordinates of the target Chinese character key points are (x i n , y i n ), wherein x i n represents the abscissa of the i-th key point of the n-th stroke of the target Chinese character, and y i n represents the ordinate of the i-th key point of the n-th stroke of the target Chinese character.

[0061] In this embodiment, (x i n , y i n ) ∈ (0,1000).

[0062] In said step S3, the relative position coordinates of the pen tip in the writing board are (bx t , by t ), wherein bx t represents the abscissa of the relative position of the pen tip in the writing board, and by t represents the ordinate of the relative position of the pen tip in the writing board.

[0063] In this embodiment, a writing coordinate system is established on the writing board, and the coordinates of the pen tip on the writing board are determined by unspecified technical means, and the pen tip recognition technologies include image recognition, electronic writing boards, capacitive writing screens, etc.

[0064] In said step S4, the position of the top-left point of the target Chinese character in the virtual mapping image is (sx, sy), wherein sx represents the abscissa of the top-left point of the target Chinese character in the virtual mapping image, and sy represents the ordinate of the top-left point of the target Chinese character in the virtual mapping image.

[0065] The aspect ratio of the virtual mapping graph is the same as the aspect ratio of the writing board;

[0066] The width of the writing board is W board , and the height of the writing board is H board ; the width of the virtual mapping graph is W map , and the height of the virtual mapping graph is H map .

[0067] In this embodiment, a virtual mapping graph is constructed. The virtual mapping graph is a rectangular area existing in a mobile phone program of a human-computer interaction module, and is a virtual mapping that reflects the writing relationship on the writing board, that is, the virtual mapping of a pen tip position and a preset Chinese character path. In the virtual mapping graph, a mapping graph coordinate system corresponding to the coordinate system of the writing board is established, and the position of the upper-left point of a target Chinese character in the mapping graph is set according to the relative position of the target Chinese character.

[0068] In the step S5, the writing track is represented as a set of the i-th key point of the n-th stroke on the virtual mapping graph , and the pen tip position is represented as (px t , py t );

[0069] The expressions of the writing track and the pen tip position are:

[0070]

[0071]

[0072]

[0073]

[0074] wherein, represents the abscissa of the i-th key point of the n-th stroke on the virtual mapping graph, represents the ordinate of the i-th key point of the n-th stroke on the virtual mapping graph, length ch represents a size parameter, px t represents the abscissa of the pen tip after being mapped to the virtual mapping graph, py t represents the ordinate of the pen tip after being mapped to the virtual mapping graph.

[0075] In this embodiment, changing the size parameter length ch can adjust the size of the written Chinese character, and changing (sx, sy) can adjust the position of the written target Chinese character.

[0076] In this embodiment, the target Chinese character is set as "人", which consists of two strokes.

[0077] The key point coordinates of each stroke are stored in the order of strokes. For example, for the first stroke (the left-falling stroke) of the Chinese character "人", we store the coordinates of its key points as For the second stroke (the right-falling stroke), we store the coordinates of its key points as wherein represents the coordinate of the first key point of the first stroke of the target Chinese character, represents the coordinate of the second key point of the first stroke of the target Chinese character, represents the coordinate of the m-th key point of the first stroke of the target Chinese character, represents the coordinate of the first key point of the second stroke of the target Chinese character, represents the coordinate of the second key point of the second stroke of the target Chinese character, represents the coordinate of the n-th key point of the second stroke of the target Chinese character, and all these coordinate values are within the range of (0, 1000).

[0078] Meanwhile, the width W of the writing board is set board to 300mm, and the height H board to 200mm. On the writing board, an image recognition technology is used to determine the real-time position of the pen tip. Assume that at a certain moment, the relative position coordinate of the pen tip in the writing board is (bx t , by t ).

[0079] In the mobile phone program of the human-computer interaction module, a virtual mapping diagram is constructed. The width W of the virtual mapping diagram map is set to 80% of the screen width, and the height H map is set to 60% of the screen height, so as to ensure that the virtual mapping diagram can be clearly displayed on the screen. Meanwhile, the aspect ratio of the virtual mapping diagram is ensured to be the same as that of the writing board. In the virtual mapping diagram, the position of the top-left point of the written target Chinese character "人" is set as (sx, sy), for example, (50, 50).

[0080] Then the size parameter length of the target Chinese character "人" to be written is set ch to 500. According to the coordinate mapping formula, the coordinates of all key points of the target Chinese character and the relative position coordinates of the pen tip are mapped into the virtual mapping diagram, realizing the function of simultaneously placing the writing path coordinates and the coordinates of the pen tip on the writing board onto the mapping diagram. The navigation system generates voice navigation information according to the writing track and the pen tip position on the mapping diagram, and performs writing navigation accurately.

[0081] The specific steps of step S6 are as follows: take the midpoint between the pen tip position coordinates and the coordinates of the previous stroke key point in the writing trajectory as the starting point coordinates of the navigation direction, take the current stroke key point coordinates as the ending point of the navigation direction, fine-tune the navigation direction through dynamic parameter a, generate voice navigation information based on the adjusted navigation direction, and complete the blind writing navigation.

[0082] The expression for calculating the navigation direction in step S6 is as follows:

[0083]

[0084]

[0085]

[0086] Where, x at The x-coordinate of the starting position of the navigation direction, y at The ordinate represents the starting position of the navigation direction, where 'a' represents a dynamic parameter. write Indicates the direction in which the text is written. write (·) represents the formula for calculating direction. This represents the x-coordinate of the (i+1)th key point of the nth stroke on the virtual mapping graph. This represents the ordinate of the (i+1)th key point of the nth stroke on the virtual mapping.

[0087] In this embodiment, all optimized coordinates of the key points of the target Chinese character are mapped onto a virtual mapping map, and the mapping set is the writing trajectory in the virtual mapping map. This embodiment calculates the navigation direction based on the coordinates of the pen tip and the coordinates of the corresponding key points in the trajectory, introducing a dynamic optimization algorithm in this process.

[0088] Before the introduction of dynamic optimization, the writing direction was: the coordinates of the previous key point point to the coordinates of the current key point. However, blind people may misunderstand the navigation direction based on voice prompts.

[0089] like Figure 3 As shown in (A), black represents the navigation direction, blue dashed lines represent the user's perceived direction, and red solid lines represent the actual conceptual direction, but there is a difference between the perceived direction and the actual conceptual direction. Figure 3 As shown in (B), the black dots are key points, the blue solid lines represent the actual writing direction, and the gray dashed lines represent the path trajectory.

[0090] Although the navigation direction is from the current key point to the next key point, there is a significant deviation between the actual writing trajectory and the predetermined path, and the gap gradually widens. To solve this problem, this invention dynamically adjusts the navigation strategy based on the visual user's cognitive space.

[0091] Therefore, a dynamic optimization algorithm is introduced: the navigation direction is designed with the starting point coordinates of the midpoint between the pen tip coordinates and the coordinates of the previous keypoint, pointing towards the current keypoint coordinates, and the navigation direction is fine-tuned using a dynamic parameter 'a'. Here, Direction... write (xat,yat,gxin +1 ,gyin +1 The calculation result is derived from the navigation starting point (x). at ,y at ) points to the target point, i.e., the current keypoint (gx) i n +1 ,gy i n +1 The direction of ). For example Figure 3 (C) shows a schematic diagram of the correction of the navigation direction.

[0092] At the start of navigation, the dynamic parameter 'a' is set to 0, and the navigation direction aligns with the line connecting adjacent navigation points. As the dynamic parameter 'a' increases, the navigation direction shifts from the current pen tip position to the next navigation point. The method for dynamically adjusting the dynamic parameter 'a' is as follows: Figure 3 As shown in (D). If the user misunderstands the navigation direction, the value of the dynamic parameter 'a' will increase. Conversely, when the user correctly understands the navigation direction, the value of the dynamic parameter 'a' will be reset to 0.

[0093] like Figure 3 As shown in (E), the dynamic optimization algorithm corrects the user's writing direction. The solid black line represents the optimized navigation direction, which adjusts the actual navigation direction to be more consistent with the expected path direction, thereby reducing the difference between the perceived direction and the actual direction. The dynamically optimized handwriting trajectory is shown below. Figure 3 As shown in (F), the yellow dashed line represents the unoptimized trajectory, and the red dashed line represents the optimized trajectory.

[0094] In summary, the spatial coordinate mapping method of this invention enables blind writing navigation systems to set navigation plans and perform path planning more conveniently and efficiently, while improving the positioning accuracy and flexibility of the system. Furthermore, coordinate mapping allows users to easily adjust the size and position of the written characters to meet individual needs. Simultaneously, the optimization algorithm makes the writing path smoother and easier to understand, improving the fluency and accuracy of writing. For example, in experiments, users with different levels of visual impairment underwent writing tests and were found to be able to adjust the writing effect according to their preferences and habits through simple operations, making the writing more in line with their personal aesthetics and writing habits. At the same time, the dynamic optimization algorithm adjusts the actual navigation direction to be more consistent with the expected path direction, thereby reducing the difference between the perceived direction and the actual direction.

Claims

1. A method for blind writing navigation based on spatial mapping and dynamic optimization, characterized in that, Includes the following steps: S1. Write the target Chinese character using a writing board and determine the coordinate sequence of the key points of the target Chinese character; S2. Analyze the distribution of key points in the coordinate sequence of key points of the target Chinese character and optimize the key points to obtain the optimized coordinates of the key points of the target Chinese character. S3. By establishing a writing coordinate system on the writing board, determine the relative position coordinates of the pen tip on the writing board; S4. Construct a virtual mapping graph and establish a coordinate system for the mapping graph to determine the position of the top-left point of the target Chinese character in the virtual mapping graph; S5. Based on the position of the top left point of the target Chinese character in the virtual mapping, map the optimized coordinates of the key points of the target Chinese character and the relative position coordinates of the pen tip to the virtual mapping to obtain the writing trajectory and pen tip position on the virtual mapping. S6. Based on the writing trajectory and pen tip position, the navigation direction is calculated through a dynamic optimization algorithm, and voice navigation information is generated according to the navigation direction to complete the writing navigation for the blind. The specific steps of step S6 are as follows: The midpoint between the pen tip position coordinates and the coordinates of the previous stroke key point in the writing trajectory is taken as the starting coordinate of the navigation direction, and the current stroke key point coordinates are taken as the ending coordinate of the navigation direction, using dynamic parameters... It can fine-tune the navigation direction and generate voice navigation information based on the adjusted navigation direction to complete the writing navigation for the blind; The expression for calculating the navigation direction in step S6 is as follows: in, The x-coordinate represents the starting position of the navigation direction. The ordinate represents the starting position of the navigation direction. Indicates dynamic parameters. Indicates the direction in which it is written. Formulas for calculating direction. Represents the first on the virtual mapping graph The first stroke The x-coordinates of the key points Represents the first on the virtual mapping graph The first stroke The ordinates of the key points.

2. The method for blind writing navigation based on spatial mapping and dynamic optimization according to claim 1, characterized in that, In step S1, the coordinate sequence of the key points of the target Chinese character is stored separately according to each stroke of the target Chinese character.

3. The method for blind writing navigation based on spatial mapping and dynamic optimization according to claim 2, characterized in that, The specific coordinates of step S2 are: S21. Analyze the distribution of the coordinate sequence of key points of the target Chinese character and determine the areas where the key points are unevenly distributed; S22. Identify sub-regions with fewer key points based on the first threshold, and insert new key points in the sub-regions with fewer key points; S23. Identify redundant key points that are too close together in the region based on the second threshold, remove the redundant key points, and obtain the optimized coordinates of the target Chinese character key points.

4. The method for blind writing navigation based on spatial mapping and dynamic optimization according to claim 3, characterized in that, The specific steps for determining the uneven distribution of key points in step S21 are as follows: calculate the distance between key points and determine the maximum distance between key points. and the minimum distance between key points ,judge Is it greater than 2? If so, the key points are unevenly distributed; otherwise, the key points are evenly distributed.

5. The method for blind writing navigation based on spatial mapping and dynamic optimization according to claim 3, characterized in that, The optimized coordinates of the key points of the target Chinese character in step S2 are: ,in, Indicates the target Chinese character number The first stroke The x-coordinates of the key points Indicates the target Chinese character number The first stroke The ordinates of the key points.

6. The method for blind writing navigation based on spatial mapping and dynamic optimization according to claim 1, characterized in that, In step S3, the relative position coordinates of the pen tip on the writing board are: ,in, The horizontal coordinate represents the relative position of the pen tip on the writing board. The vertical coordinate represents the relative position of the pen tip on the writing board.

7. The method for blind writing navigation based on spatial mapping and dynamic optimization according to claim 6, characterized in that, In step S4, the position of the top-left point of the target Chinese character in the virtual mapping map is: ,in, This represents the x-coordinate of the top-left point of the target Chinese character in the virtual mapping. This represents the vertical coordinate of the top-left point of the target Chinese character in the virtual mapping.

8. The method for blind writing navigation based on spatial mapping and dynamic optimization according to claim 7, characterized in that, The aspect ratio of the virtual mapping is the same as that of the writing board; The width of the writing board is The height of the writing board is The width of the virtual mapping graph is The height of the virtual mapping graph is .

9. The method for blind writing navigation based on spatial mapping and dynamic optimization according to claim 8, characterized in that, In step S5, the writing trajectory is represented as the first on the virtual mapping graph. The first stroke Key points The set, wherein the pen tip position is represented as ; The expressions for the writing trajectory and pen tip position are: in, Represents the first on the virtual mapping graph The first stroke The x-coordinates of the key points Represents the first on the virtual mapping graph The first stroke The ordinates of the key points Indicates dimensional parameters, This represents the x-coordinate of the pen tip after it has been mapped onto the virtual map. This represents the vertical coordinate after the pen tip is mapped onto the virtual mapping graph.

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