National dance digital display system

Abstract

The invention relates to the technical field of digital display, in particular to a national dance digital display system which comprises a track node extraction module, a rhythm segment optimization module, a trend stability recognition module, an action information acquisition module and a synchronous recombination execution module. According to the method, angle abrupt change points are extracted by constructing spatial vectors, action change recognition is enhanced, the frame sequence structure analysis precision is improved, time length and amplitude dual stability standards are introduced in beat paragraph screening, the accuracy and robustness of rhythm recognition are enhanced, trend stable frames are extracted through slope fluctuation comparison, and the accuracy and robustness of rhythm recognition are improved. The continuity of the rhythm flow direction and the centrality of node selection are ensured, the main limb movement is constructed by the path total distance, the direction angle and the frame time sequence, the clear structure and the consistent direction of the movement expression are ensured, the direction correction and rhythm scaling strategy is introduced in the dynamic recombination process, the smooth movement transition and the rhythm synchronization are ensured, and the reorganization efficiency is improved. And the rhythm coordination and the dynamic coherence of dance actions are obviously improved.

Description

Technical Field

[0001] The invention relates to the technical field of digital display, and in particular to a digital display system for folk dances. Background Art

[0002] The field of digital display technology includes methods and applications related to information collection, digital modeling, visualization and interactive presentation of physical or cultural objects using digital media and computer technology. The core content includes image acquisition and processing, three-dimensional modeling, digital content reconstruction, visual interaction design and display terminal presentation. Digital display is widely used in cultural heritage protection, education and training, virtual museums, stage art communication and other fields. Its overall technical system emphasizes the high-fidelity collection and reconstruction of objects or activities in the real world in digital form and presenting them to users in a visual way, so as to realize the digital reproduction and interactive expression of physical space or cultural content.

[0003] The digital display system for ethnic dances refers to a special digital platform for collecting, processing and displaying ethnic dance cultural resources, covering the acquisition of dance movement data, three-dimensional modeling of dance forms, digital animation production of dance performance processes, and graphical display of dance content. Specifically, it uses three-dimensional motion capture technology to collect dynamic data on dancers' body movements, combines computer graphics processing methods to generate editable three-dimensional dance movement models, and converts model movements into visual images through graphics rendering methods, and performs digital demonstrations on display terminal devices.

[0004] In the existing ethnic dance display process, there is a lack of multi-dimensional analysis of the dynamic structure in the dance action sequence during the operation process. It often relies on modeling and rendering of the entire action, and fails to deeply extract the changing characteristics and rhythmic laws within the action, resulting in a relatively flat presentation of the content. The key node recognition method in the frame sequence is single, relying only on continuous action recording rather than extraction based on spatial change features, resulting in inaccurate judgment of the fluctuation of the action between frames, affecting the structural accuracy of the subsequent reconstruction. At the rhythm processing level, there is no stability screening mechanism for the recognition of different beat sections, and the beat fluctuations are not effectively distinguished, resulting in problems such as fuzzy rhythm expression and beat confusion. In trend processing, the changing trend of the action trend is ignored, and the action is only presented in the surface time series, lacking the recognition of the internal change trend, affecting the temporal tension of the display content. The display content is mostly based on the reproduction of the original action, without achieving direction unification and beat reconstruction, resulting in a lack of overall rhythm and structural logic in the dynamic expression form. For example, when displaying a dance segment with obvious rhythm fluctuations, high-frequency oscillations or direction jumps are prone to occur, which interferes with the accuracy and viewing of the dance language. Summary of the invention

[0005] The purpose of the present invention is to solve the shortcomings in the prior art and to propose a digital display system for folk dance.

[0006] In order to achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a digital display system of folk dance comprises: The trajectory node extraction module obtains the three-dimensional position coordinates of the folk dance movements, constructs the space vector and calculates the angle value, determines and records the angle mutation point, and generates the turning frame index sequence; The rhythm segment optimization module obtains the beat duration and beat amplitude of the turning section based on the turning frame index sequence, calculates the difference between the maximum and minimum values ​​of the beat duration and amplitude, compares the beat stability threshold, and selects the beat stable section; The trend stability identification module extracts the spatial position coordinates of the corresponding frame points according to the beat stability paragraph, performs linear fitting and extracts the corresponding fitting slope, determines the continuous paragraph with the smallest fluctuation amplitude and extracts the frame index, and generates trend stability node index data; The motion information acquisition module obtains the three-dimensional position points of each frame of the main limb according to the trend stable node index data, calculates the sum of the path distance, constructs the direction vector and calculates the direction angle, and obtains the main limb motion information by combining the starting frame and the total number of frames; The synchronous reorganization execution module calculates the rotation angle and performs direction correction according to the main limb movement information, scales all frame time duration values ​​proportionally, rearranges the frame sequence to construct a new dynamic structure, and obtains the dynamic display result of the ethnic dance.

[0007] As a further solution of the present invention, the turning frame index sequence includes action change nodes, turning angle distribution, and action section boundaries; the beat stable paragraph includes beat balance index, rhythm start and end information, and stability interval identification; the trend stable node index data includes stable trend reference frame, fitting change range, and rhythm trend parameters; the main limb movement information includes action path characteristics, direction change parameters, and action timing structure; the dynamic display result of the ethnic dance includes reorganized action frame sequence, unified direction posture, and beat synchronization rhythm.

[0008] As a further solution of the present invention, the trajectory node extraction module includes: The three-dimensional coordinate extraction submodule obtains the three-dimensional position coordinate data of the dancer's skeleton in each frame based on the video frame sequence of the continuous stepping action of the folk dance, extracts the three-dimensional coordinates of the dancer's foot joints in each frame in turn, organizes and stores them as a three-dimensional coordinate set sorted by frame order, and generates a three-dimensional coordinate sequence of the dance gait; The spatial vector construction submodule constructs two sets of spatial vectors according to the dance gait three-dimensional coordinate sequence and the coordinates of two adjacent gait trajectories between every three frames, calculates the angle value in each set of three frames, integrates the angle results between all three frames, and generates a spatial gait angle value sequence; The angle mutation judgment submodule uses the formula according to the spatial gait angle value sequence: ; Calculate the Frame angle value , according to the frame index whose angle mutation amplitude value is greater than the angle mutation threshold, extract and record the frame position, obtain and establish the turning frame index sequence, where, For the The space vector of the frame construction, is the module length, For the Frame foot key point distance, For the Frame timestamp, For the Frame angle mutation amplitude value, For the Frame angle mutation amplitude value, For the Frame foot key point distance, For the Frame timestamp.

[0009] As a further solution of the present invention, the rhythm segment optimization module includes: The beat feature extraction submodule extracts the time interval between adjacent transition frames based on the transition frame index sequence to obtain the beat duration, calls the three-dimensional coordinate information in the corresponding frame to calculate the beat amplitude, and generates a rhythm segment beat feature sequence; The beat difference calculation submodule calculates the difference between the maximum and minimum values ​​of the beat duration set and amplitude set in each segment according to the beat feature sequence of the rhythm segment, using the formula: ; Calculate the Segment beat difference combination value , and obtain the beat difference combination value sequence, where , Respectively represent The maximum and minimum duration of the segment beat, , Respectively represent The maximum and minimum values ​​of the segment beat amplitude; The stable paragraph screening submodule determines whether the combination value in each rhythm segment is less than the beat stability threshold value according to the beat difference combination value sequence, screens all rhythm segments that meet the conditions, and establishes a beat stable paragraph.

[0010] As a further solution of the present invention, the trend stability identification module includes: The coordinate extraction submodule extracts all frame indexes corresponding to each segment according to the stable beat segment, obtains the three-dimensional spatial position coordinates corresponding to the frame index, combines and records the coordinate sequences of each segment in chronological order, and generates stable segment spatial coordinate data; The trend fluctuation calculation submodule performs a linear fitting operation on the sequence of the three-dimensional spatial coordinates in each paragraph changing with time based on the stable paragraph spatial coordinate data, obtains the linear fitting slope value of each paragraph in the main time axis direction, compares the change intensity between all slope values, and establishes a composite calculation relationship between the slope change amount of adjacent paragraphs and the paragraph length, using the formula: ; Calculate the combined trend fluctuation value , extract the stable trend segment according to the continuous segment number interval with the smallest fluctuation value, and get the trend stable interval, where, For the The linear fitting slope value of the segment, For the The linear fitting slope value of the segment, For the The number of frames in the segment, From paragraph 1 to Segment accumulation operation, denominator To avoid division by zero, It is the absolute value of the product of the slope value and the inverse segment length, which is used to measure the sensitive response of trend instability in a shorter segment. Indicates the total number of segments; The node index generation submodule extracts all frame index sets in each stable segment according to the trend stable interval, calculates the median position according to the time position, extracts the corresponding frame index, and establishes trend stable node index data.

[0011] As a further solution of the present invention, the action information acquisition module includes: The main limb coordinate extraction submodule extracts all frame indexes of the rhythm segment to which the node belongs according to the trend stable node index data, obtains the three-dimensional position coordinates of the main limb in each frame, and arranges them into a continuous coordinate sequence arranged in frame order to generate a main limb time series coordinate sequence; The motion path calculation submodule calculates the spatial distances between adjacent frame points in frame order based on the main limb temporal coordinate sequence, extracts the coordinate difference between the first frame and the last frame to represent the direction, and uses the formula: ; Calculate path direction combination value , revealing the total displacement and direction changes of the action, and obtaining the main limb space motion parameters, among which, For the Frame and The 3D distance between frames, , is the coordinate value of the main limb on the x-axis in the first frame and the last frame, is the total number of frames in the rhythm segment; The motion information construction submodule constructs and summarizes the corresponding structured fields according to the main limb spatial motion parameters, combined with the starting frame number and the number of frames of each segment, to establish the main limb motion information.

[0012] As a further solution of the present invention, the synchronous reorganization execution module includes: The direction correction submodule traverses all frame points in the current rhythm segment frame by frame according to the main limb movement information, extracts the spatial direction vector of the main limb in each frame, calculates the angle difference between the current direction and the starting direction, and adjusts the direction vector of the current frame to maintain consistency with the initial direction, thereby generating a direction-consistent vector sequence; The time scaling submodule performs a proportional scaling operation on the time duration value corresponding to each frame based on the direction consistent vector sequence, and reallocates the new time point position corresponding to each frame according to the actual time length of the rhythm segment start time and the beat cycle to obtain a geometrically aligned time sequence; The structure rearrangement submodule rearranges the order of all frames in the rhythm segment according to the geometric alignment time sequence, and reconstructs the coordinates, direction and time label corresponding to each frame, and uniformly organizes them into continuous dynamic structure data to obtain the dynamic display result of the ethnic dance.

[0013] Compared with the prior art, the advantages and positive effects of the present invention are: In the present invention, by constructing a spatial vector for every three frames of dance movements and extracting angle mutation points, a dynamic node screening mechanism based on angle features is formed, the sensitive recognition ability of movement changes is enhanced, the selection of beat sections no longer relies solely on time segmentation, but comprehensively considers the difference in beat duration and amplitude stability, accurately locks the action interval with clear rhythm structure, improves the discrimination accuracy of rhythm section selection, quantifies the fluctuation of adjacent linear fitting slopes, strengthens the trend continuity recognition ability, and makes the node selection have stronger time centrality and trend representativeness. In the extraction of main limb movement features, the total path distance, direction angle and The three indicators of frame timing work together to improve the structural integrity and directional consistency of movement expression. In the subsequent reorganization of dynamic frame sequences, the rotation angle correction and timeline proportional scaling methods are integrated to make the rhythm transition between frames more natural, and the timing beat and movement rhythm synchronized and unified, enhancing the overall display of dynamic aesthetics and rhythmic expressiveness. The overall processing path takes structural feature extraction as the starting point, rhythm stability identification as the central axis, and movement dynamic reorganization as the core, forming a dance digital display framework with spatial nodes, rhythm structure and time regulation as the trinity, constructing a dynamic presentation effect with more rhythm coordination and movement coherence. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a system flow chart of the present invention; Figure 2 This is a flow chart of the trajectory node extraction module of the present invention; Figure 3 The present invention is a flow chart of the rhythm segment optimization module; Figure 4 This is a flow chart of the trend stability identification module of the present invention; Figure 5 This is a flow chart of the action information collection module of the present invention; Figure 6 This is a flow chart of the synchronous reorganization execution module of the present invention. DETAILED DESCRIPTION

[0015] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0016] In the description of the present invention, it should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, in the description of the present invention, "multiple" means two or more, unless otherwise clearly and specifically defined.

[0017] See also Figure 1 , a national dance digital display system includes: The trajectory node extraction module obtains the three-dimensional position coordinates of each frame in the continuous stepping action of the folk dance, constructs the space vector between every three frames and calculates the angle value, makes angle judgments on all angle values ​​and records the frame index of the angle mutation point, and generates a transition frame index sequence; The rhythm segment optimization module obtains the beat duration and beat amplitude in each transition segment based on the transition frame index sequence, calculates the maximum and minimum difference of the beat duration and the maximum and minimum difference of the amplitude of each segment, compares the beat stability threshold, and selects the beat segments that simultaneously meet the two differences less than the stability threshold to obtain the beat stable segment; The trend stability identification module extracts the spatial position coordinates of the corresponding frame points according to the beat stable paragraphs, performs linear fitting and extracts the corresponding fitting slopes, compares the fluctuation values ​​between adjacent slopes, determines the continuous paragraphs with the smallest fluctuation amplitude and extracts the frame index with the middle time position in the corresponding paragraph, and generates trend stable node index data; The motion information acquisition module obtains the three-dimensional position points of each frame of the main limb in the rhythm segment according to the trend stable node index data, calculates the sum of the path distances between each continuous frame, extracts the first and last frame coordinates to construct the direction vector and calculates the direction angle, and combines the start frame with the total number of frames to construct the main limb motion information; The synchronous reorganization execution module traverses all frame points in the current rhythm segment frame by frame according to the main limb movement information, calculates the rotation angle of the direction vector of each frame and performs direction correction, scales the time duration values ​​of all frames according to the actual time line of the current segment beat cycle, rearranges the frame sequence to construct a new dynamic structure, and obtains the dynamic display result of the ethnic dance.

[0018] The turning frame index sequence includes action change nodes, turning angle distribution, and action segment boundaries. The beat stable segment includes beat balance indicators, rhythm start and end information, and stability interval identification. The trend stable node index data includes stable trend reference frames, fitting change range, and rhythm trend parameters. The main limb movement information includes action path characteristics, direction change parameters, and action timing structure. The dynamic display results of ethnic dance include reorganized action frame sequences, unified direction posture, and beat synchronization rhythm.

[0019] See also Figure 2 ,The trajectory node extraction module includes: The three-dimensional coordinate extraction submodule obtains the three-dimensional position coordinate data of the dancer's skeleton in each frame based on the video frame sequence of the continuous stepping action of the folk dance, extracts the three-dimensional coordinates of the dancer's foot joints in each frame in turn, organizes and stores them as a three-dimensional coordinate set sorted by frame order, and generates a three-dimensional coordinate sequence of the dance gait; Based on the video frame sequence of continuous stepping movements of folk dance, it is necessary to first collect the image information of each frame in the video and locate the key points of the dancer in the image. Then, the three-dimensional coordinate information of the joints of the dancer's feet in each frame is extracted by combining the image recognition processing program. In the actual acquisition process, the shooting frequency can be set to 30 frames per second. After recording 1 minute of dance movements, 1800 frames of image data can be obtained. The three-dimensional coordinates of the key points of the feet are extracted from the image to form a set of three-dimensional vector arrays, in which the x, y, and z axis data represent the spatial position coordinates respectively. Each frame of data is traversed in turn and sorted in chronological order to obtain a complete coordinate sequence, for example The coordinates of the left foot in the 28th frame are (21.3, 48.6, 18.9), and the coordinates of the right foot are (26.7, 47.9, 19.4). The midpoint of the left and right feet is used as the gait center point, and a three-dimensional coordinate sequence of the dance gait can be formed through multi-frame coordinate data. For the continuous stepping situation that appears in the dance, the frame segments with obvious continuous gait changes can be intercepted for feature extraction. The extraction process needs to eliminate data segments with almost no change in position between frames. For example, data segments with a frame difference of less than 2 cm are not included in the sequence construction range. The coordinate data retained after filtering is the effective data of gait changes, forming a three-dimensional coordinate sequence of the dance gait.

[0020] The spatial vector construction submodule constructs two sets of spatial vectors based on the dance gait three-dimensional coordinate sequence and the coordinates of two adjacent gait trajectories between every three frames, calculates the angle value within each set of three frames, integrates the angle results between all three frames, and generates a sequence of spatial gait angle values; After obtaining the dance gait three-dimensional coordinate sequence, the three consecutive frames in the sequence need to be constructed into two sets of vectors. Each set of vectors is composed of the midpoint coordinates of the two frames before and after. For example, in the 28th to 30th frames, the midpoint coordinates of the 28th and 29th frames are respectively taken to form the first vector , take the 29th and 30th frames to form the second vector , respectively calculate the direction and length of the two vectors, according to the three-dimensional space vector angle cosine calculation formula Calculate the vector angle , the angle is the degree of the spatial angle formed by the dance action in this frame segment. Indicates that the action converges. If This means that the turning point is large. To avoid fuzzy definition, it is necessary to set the boundary reference interval of the angle. is the normal swing range of the dance step. Below this range is a closed posture, and above this range is a large leg swing. The system will perform the above angle calculation on each group of three frames in turn and generate corresponding angle value data to form a spatial gait angle value sequence. The angle value calculation involves vector inner product operation and module length calculation process, such as: ; The module length is: ; Performing this type of operation on all frame segment data can obtain a complete sequence of spatial gait angle values.

[0021] The angle mutation judgment submodule uses the formula according to the sequence of spatial gait angle values: ; Calculate the Frame angle value , according to the frame index whose angle mutation amplitude value is greater than the angle mutation threshold, extract and record the frame position, obtain and establish the turning frame index sequence, where, For the The space vector of the frame construction, is the module length, For the Frame foot key point distance, For the Frame timestamp, For the Frame angle mutation amplitude value, For the Frame angle mutation amplitude value, For the Frame foot key point distance, For the Frame timestamp; According to the spatial gait angle value sequence, the angle value of each frame The difference between the angles of adjacent frames is calculated based on , further combined with the frame vector inner product, vector modulus and the distance change trend of the gait key points in the frame for weighted synthesis to determine whether an angle mutation occurs, where the threshold is set =15° is based on the following: in the continuous stepping movements of folk dances, the dancers’ body posture transitions are usually manifested as a significant increase in the change of the spatial angle. Combined with the comparison of the time span and the action rhythm under the condition of a video frame rate of 10fps, in the same dance segment, when the angle change value exceeds 12°, it shows a change in the gait amplitude trend, and when the angle change exceeds 15°, it is accompanied by a change in the foot support surface or gait fluctuations. Therefore, based on this interval, Set to 15°. This value fluctuates with the dancer's step frequency (i.e., the number of steps per unit time) and the moving speed of key points between frames. Its changing trend can be adjusted by the median level of the frame segment with the largest angle change per unit time in the dance segment as the dynamic change adjustment benchmark to ensure that the key turning points corresponding to the structural movement changes are captured. Then the frame is judged as a turning frame. Time interval Usually it is 0.1s (when the frame rate is 10fps). Substitute the data in the table for calculation. The specific calculation for the 29th frame is: ; Calculate in sequence: ; The value It is obviously larger than the set threshold of 15°, so the 29th frame is marked as a turning frame, the frame index is automatically recorded, and a turning frame index sequence is established.

[0022] Table 1 Angle judgment calculation parameter table: ; As shown in Table 1, the angle, vector and spatial parameters of three consecutive frames are extracted for subsequent judgment.

[0023] Table 2 Angle mutation amplitude calculation results: ; Table 2 gives the angle mutation amplitude value of the 29th frame. The results show that this frame is the key position point of the structural change of the dance step and can be marked as a turning frame and participate in subsequent recognition operations.

[0024] See also Figure 3 , the rhythm segment optimization module includes: The beat feature extraction submodule extracts the time interval between adjacent transition frames to obtain the beat duration based on the transition frame index sequence, calls the three-dimensional coordinate information in the corresponding frame to calculate the beat amplitude, and generates the rhythm segment beat feature sequence; Based on the turning frame index sequence, the timestamp information between adjacent frames is extracted in sequence, and the time difference between the two frames is calculated to represent the beat duration. For example, in rhythm segment D1, the turning frame timestamps are 12.0 seconds and 13.5 seconds respectively, and the time interval is 1.5 seconds, indicating that the beat duration of this segment is 1.5 seconds; then, according to the three-dimensional position information of the frames in the turning interval, the maximum and minimum values ​​of the z-axis coordinates of the foot are extracted, and the difference is calculated as the beat amplitude. For example, if the foot is raised from 0.05 meters to 0.45 meters in the z-axis direction, the beat amplitude of this segment is 0.40 meters. Subsequently, in rhythm segment D2, the timestamp changes from 15.0 seconds to 17.0 seconds, the beat duration is 2.0 seconds, and the corresponding amplitude is from 0.18 meters to 0.50 meters, and the amplitude is 0.32 meters. In rhythm segment D3, the time span is 1.95 seconds, and the amplitude is 0.30 meters. The same operation is performed on all rhythm segments in sequence to generate a beat feature data set as shown in Table 3; Table 3 Rhythm segment parameter setting table: ; As shown in Table 3, each rhythm segment includes the maximum and minimum values ​​of the beat duration and the maximum and minimum values ​​of the beat amplitude. On this basis, the parameters of each segment are extracted to generate the beat feature sequence of the rhythm segment.

[0025] The beat difference calculation submodule calculates the difference between the maximum and minimum values ​​of the beat duration set and amplitude set in each segment according to the beat feature sequence of the rhythm segment, using the formula: ; Calculate the Segment beat difference combination value , and obtain the beat difference combination value sequence, where , Respectively represent The maximum and minimum duration of the segment beat, , Respectively represent The maximum and minimum values ​​of the segment beat amplitude; According to the beat feature sequence of the rhythm segment, the difference between the maximum and minimum values ​​of each beat duration and beat amplitude is calculated and brought into the combination calculation formula. For example, for the rhythm segment D1, it is known that , , , , substituting into the formula: ; ; For rhythm section D2, substitute , , , , substituting into the formula: ; ; The same calculation is performed on rhythm segment D3 to obtain , and then obtain the beat difference combination value sequence.

[0026] The stable paragraph screening submodule determines whether the combination value in each rhythm segment is less than the beat stability threshold according to the beat difference combination value sequence, screens all rhythm segments that meet the conditions, and establishes a beat stable paragraph; According to the beat difference combination value sequence, the beat stability threshold is set to 0.7, and each rhythm segment is judged in turn. If its difference combination value is less than the beat stability threshold, it is judged as a stable segment. For example, the combination value of rhythm segment D1 is 0.3765, D2 is 0.4449, and D3 is 0.53. All three are lower than the threshold and are marked as stable segments. Finally, their numbers and corresponding parameters are sorted into the structure set to obtain a beat stable segment. Among them, the setting basis of the beat stability threshold of 0.7 is the joint distribution interval analysis results of the maximum and minimum difference of beat duration and amplitude difference in multiple dance sequences. Comparison and extraction are carried out in 90 groups of ethnic dance samples, and the statistical difference combination value distribution mean is 0. 48, the standard deviation is 0.11, and the beat stability threshold is set to the upper limit of the interval of the mean plus 2 times the standard deviation, that is, the beat stability threshold = 0.48 + 2 × 0.11 = 0.7, to ensure that the screened beat segments are highly consistent; this threshold can be adjusted with the change of the stride average value and the action cycle in different types of movements. The larger the stride and the longer the action cycle, the higher the volatility of the beat amplitude and duration, and the beat stability threshold can be appropriately increased. For example, in the analysis of intense dance segments, the beat stability threshold can be set to 0.8 to 0.85, while in slow-rhythm segments, the beat stability threshold should be 0.6 to 0.65, so as to adjust the threshold range according to the rhythm structure of the dance type to ensure that it can accurately identify the structurally stable segments in the action beat distribution.

[0027] See also Figure 4 , the trend stability identification module includes: The coordinate extraction submodule extracts all frame indexes corresponding to each segment according to the beat stable segment, obtains the three-dimensional spatial position coordinates corresponding to the frame index, combines and records the coordinate sequence of each segment in time order, and generates the stable segment spatial coordinate data; According to the set of stable rhythmic paragraphs, first extract all the index numbers from the start frame to the end frame in each paragraph. Combined with the continuous timing information of the folk dance steps, paragraph 1 can be taken as frame numbers 120 to 140, paragraph 2 as frame numbers 141 to 158, and paragraph 3 as frame numbers 159 to 180. After extracting these frame indexes one by one, use the motion capture system or frame image reconstruction module to obtain the spatial three-dimensional coordinates of the key parts of the dancer's body. The coordinate items are generally the spatial positions of the points in the x, y, and z directions in meters. For example, the 125th The coordinates of the left ankle in the frame can be (0.36, 0.12, 0.08), and the 126th frame is (0.37, 0.12, 0.09). In the process of obtaining coordinates, the spatial trajectory changes of adjacent frames are normalized so that the position coordinates of each frame in each segment correspond to the time series in this segment. Then, the spatial position matrix is ​​constructed according to the order of segment division. The data in each segment consists of time and three-dimensional coordinates. For example, the time series in paragraph 1 is [0, 1, 2, ..., 19], and the corresponding coordinate sequence is , the coordinate sequence of each segment is summarized as input data to obtain stable segment space coordinate data.

[0028] The trend fluctuation calculation submodule performs a linear fitting operation on the sequence of three-dimensional spatial coordinates changing with time in each paragraph based on the stable paragraph spatial coordinate data, obtains the linear fitting slope value of each paragraph in the direction of the main time axis, compares the change intensity between all slope values, and establishes a composite calculation relationship between the slope change of adjacent paragraphs and the paragraph length, using the formula: ; Calculate the combined trend fluctuation value , extract the stable trend segment according to the continuous segment number interval with the smallest fluctuation value, and get the trend stable interval, where, For the The linear fitting slope value of the segment, For the The linear fitting slope value of the segment, For the The number of frames in the segment, From paragraph 1 to Segment accumulation operation, denominator To avoid division by zero, It is the absolute value of the product of the slope value and the inverse segment length, which is used to measure the sensitive response of trend instability in a shorter segment. Indicates the total number of segments; Based on the stable paragraph spatial coordinate data, a linear fit is performed on the main axis of the frame coordinate sequence in each paragraph. The main axis is the x-axis of the main direction of the dancer's movement. The fitting slope represents the rate of change of the spatial movement trend of the segment. For example, in paragraph 1, the linear fitting slope , paragraph 2 , paragraph 3 , paragraph 4 , record the fitting slope of each segment and count its corresponding frame length L, and get , , , ,As shown in Table 4, the trend fluctuation combination values ​​between adjacent paragraphs are further calculated.

[0029] Table 4: Example of stable segment slope value and frame length: ; As shown in Table 4, the linear fitting slope value and its corresponding frame length of each segment in the stable segment are listed.

[0030] Substitute the above data into the formula for calculation: Item 1: ; ; ; Item 2: ; ; ; Item 3: ; ; ; Add all the values ​​together to get the total: ; Therefore, the combined trend fluctuation value of this segment is 0.00253, as shown in Table 5. The values ​​are sorted and the minimum value interval is selected for the next stage of operation to generate a trend stable interval sequence.

[0031] Table 5 Trend fluctuation combination value calculation process parameters: ; Table 5 lists the parameters and intermediate values ​​used in the trend fluctuation combination value calculation formula.

[0032] The node index generation submodule extracts all frame index sets in each stable segment according to the trend stable interval, calculates the median position according to the time position, extracts the corresponding frame index, and establishes the trend stable node index data; According to the trend stable interval sequence, for example, when the combined fluctuation value of paragraphs 2 and 3 is the lowest, the time position set corresponding to the interval is extracted, that is, frame numbers 141 to 180, and the total number of frames is 40 frames. The middle position frame is frame number 141 + (180-141) / 2 = 160.5, and the frame index is extracted and recorded as the trend node index value. In this way, all trend stable intervals are traversed to obtain the corresponding middle position frame numbers, and finally the trend stable node index data is established.

[0033] See also Figure 5 , the action information collection module includes: The main limb coordinate extraction submodule extracts all frame indexes of the rhythm segment to which the node belongs based on the trend stable node index data, obtains the three-dimensional position coordinates of the main limb in each frame, and organizes them into a continuous coordinate sequence arranged in frame order to generate a main limb time series coordinate sequence; According to the trend stable node index data, the rhythm segment number corresponding to each paragraph is extracted, and the three-dimensional coordinate value of the main limb is obtained in each rhythm segment in frame order, and each frame number is mapped and stored with its corresponding coordinate. In the specific implementation, as shown in Table 1, the main limb coordinate data of 5 frames in a certain rhythm segment are recorded, and the units of the X, Y, and Z axes are meters. The data is extracted frame by frame through an optical motion capture device and unified into values ​​under the absolute coordinate system. The coordinate points are arranged in time order. The first step is to read the frame numbers corresponding to all node indexes and find the rhythm segment in which they are located. All frame sequences of the segment are filtered out through the segment number, such as frame 1 to frame 5, and then the position value of the main limb in each frame in the three-dimensional coordinate is extracted to form a time-continuous coordinate sequence. In this example, the main limb may be the shoulder joint of the right arm. After obtaining its three-dimensional spatial coordinates from frame 1 to frame 5, the generated main limb time series coordinate sequence is a vector group, and its length is consistent with the number of paragraph frames. Through this sequence, path and direction calculation can be further performed to obtain the main limb time series coordinate sequence.

[0034] Table 6 Example of main limb frame point spatial coordinates: ; As shown in Table 6, this paragraph contains five frames, and the three-dimensional coordinates of the main limbs show an increasing trend along the timeline.

[0035] The motion path calculation submodule calculates the spatial distances between adjacent frame points in sequence based on the temporal coordinate sequence of the main limbs, extracts the coordinate difference between the first frame and the last frame to represent the direction, and uses the formula: ; Calculate path direction combination value , revealing the total displacement and direction changes of the action, and obtaining the main limb space motion parameters, among which, For the Frame and The 3D distance between frames, , is the coordinate value of the main limb on the x-axis in the first frame and the last frame, is the total number of frames in the rhythm segment; Based on the main limb time series coordinate sequence, the spatial path distance between adjacent frames is calculated, and the X-coordinate values ​​of the first and last frames are extracted to construct the direction item. The path distance calculation uses the three-dimensional Euclidean distance. For frames 1 to 5 in this example, the distances from frame 1 to frame 2, frame 2 to frame 3, frame 3 to frame 4, and frame 4 to frame 5 are calculated respectively. Assume that the distance between each pair of adjacent frames is , calculated using the formula.

[0036] The path distance is: ; ; ; ; The path accumulation term is: ; The direction items are: ; The final combined value is: ; The result shows that the main limb has a synthetic motion of 0.703 meters in the path and direction within this section. This value will be used as the main limb spatial feature to construct the main limb spatial motion parameters.

[0037] The action information construction submodule constructs and summarizes the corresponding structured fields based on the spatial motion parameters of the main limb, combined with the starting frame number and the number of frames of each segment, to establish the main limb action information; According to the main limb spatial motion parameters, the starting frame index and the total number of frames of each segment are extracted. Based on this structure, a unified action information data field structure is constructed, which includes the path direction combination value, starting frame number, number of frames, average displacement, etc., and finally assembled into a single-segment main limb action information object. For example, the starting frame number of the current segment is 1, the total number of frames is 5, and the path direction combination value is 0.703 meters, which can be expressed as a set of parameter data sets. The constructed structure is as follows: Starting frame number: 1; Number of frames: 5; Path direction combined value: 0.703; Average path displacement: 0.703÷5≈0.1406; In this way, the main limb movement fields of each rhythm segment are uniformly constructed to generate the main limb movement information.

[0038] See also Figure 6 , the synchronous reorganization execution module includes: The direction correction submodule traverses all frame points in the current rhythm segment frame by frame according to the main limb movement information, extracts the spatial direction vector of the main limb in each frame, calculates the angle difference between the current direction and the starting direction, and adjusts the direction vector of the current frame to maintain consistency with the initial direction, generating a direction-consistent vector sequence; According to the main limb action information, the operation of traversing all the frame points in the current rhythm segment frame by frame needs to be processed in combination with the direction vector information of each frame in the action frame structure. In the specific implementation, the frame number sequence involved in the current rhythm segment is first extracted, such as the frame group numbered 1 to 5, each frame contains the three-dimensional coordinate points of the main limb, and the unit direction vector is calculated through the first frame and the next frame and set as the reference direction, and then the direction angle is calculated for each subsequent frame in turn, where the angle calculation can be performed through the vector dot product. For example, in frame 2, the direction of the first frame is set to vector (1, 0, 0), and the direction of frame 2 is set to unit vector (0.996, 0.087, 0), the dot product of the two vectors is 0.996, and the corresponding angle is about 5°, so frame 2 The rotation angle difference is 5°, the direction of frame 3 is (0.984, 0.173, 0), the dot product is 0.984, and the angle is about 10°. Similarly, the rotation angle of frame 4 is 7°, and that of frame 5 is 2°. The angle values ​​are stored in the rotation angle sequence in turn, and then the direction correction operation is performed. The current direction vector of each frame is rotated and corrected according to the starting direction angle. The correction method uses a plane rotation operation around the vertical axis, and the coordinate rotation is updated by constructing a rotation transformation matrix. After each frame is rotated, the direction vector is rewritten into the frame data structure, and the direction sequence is updated synchronously, so that all frame direction vectors are aligned to the starting frame direction, and frame vector data with a unified direction is obtained, generating a vector sequence with a consistent direction.

[0039] The time scaling submodule performs proportional scaling operations on the time duration value corresponding to each frame based on the direction-consistent vector sequence, and reallocates the new time point position corresponding to each frame according to the actual time length of the rhythm segment start time and the beat cycle to obtain a geometrically aligned time sequence; After obtaining the direction-consistent vector sequence, in order to unify the time sequence and rhythm beat consistency of each frame, the original time point is proportionally transformed. In the specific implementation, the original time point is first extracted. For example, the sampling times of the current frames 1 to 5 are 0ms, 200ms, 400ms, 600ms, and 800ms respectively, and the total time span of the rhythm segment is 800ms. The rhythm segment is set to match the periodic beat of 1000ms. Therefore, the 800ms original interval needs to be geometrically mapped to the 1000ms interval, and proportional scaling is performed. Frame 2 is adjusted to (200 / 800)×1000=250ms, frame 3 is (400 / 800)×1000=500ms, frame 4 is 750ms, and frame 5 is 1000ms. The scaled time point is rewritten into the corresponding data field of each frame, and the synchronous timing structure is formed by combining parameters such as frame number, starting direction angle, current direction angle and rotation angle difference. The specific data is shown in the following table: Table 7: Example of ethnic dance frame-level direction and time rearrangement: ; As shown in Table 7, after completing the scaling process of each frame time point, the updated time point can be strictly aligned with the rhythm segment periodic line, and finally a geometrically aligned time series is obtained.

[0040] The structure rearrangement submodule rearranges the order of all frames in the rhythm segment according to the geometric alignment time series, and reconstructs the coordinates, direction and time labels corresponding to each frame, and uniformly organizes them into continuous dynamic structure data to obtain the dynamic display results of ethnic dance; According to the geometric alignment time series, the frame order and each parameter field are reorganized and constructed. First, the frame numbers are sorted in ascending order according to the zoomed time point. The time of frame 1 is 0ms, frame 2 is 250ms, and so on to frame 5 at 1000ms. The corresponding frame number sequence does not need to be adjusted, but the coordinate and direction data need to be repackaged. The three-dimensional spatial coordinates, consistent direction vectors and zoomed time points of each frame after sorting are combined into a unified frame data structure. Each frame structure contains fields such as frame number, three-dimensional coordinate point, direction vector and zoom timestamp. This data structure supports sequential calls during subsequent dynamic display rendering. In addition, all frame data are organized into a time-ordered continuous dynamic set, which can eventually be output to a three-dimensional action display module or rendering engine for display to establish a dynamic display result of ethnic dance.

[0041] The above are only preferred embodiments of the present invention and are not intended to limit the present invention in other forms. Any technician familiar with the profession may use the technical contents disclosed above to change or modify them into equivalent embodiments with equivalent changes and apply them to other fields. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the technical solution of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A digital display system for folk dance, characterized in that: The system comprises: The trajectory node extraction module obtains the three-dimensional position coordinates of the folk dance movements, constructs the space vector and calculates the angle value, determines and records the angle mutation point, and generates the turning frame index sequence; The rhythm segment optimization module obtains the beat duration and beat amplitude of the turning section based on the turning frame index sequence, calculates the difference between the maximum and minimum values ​​of the beat duration and amplitude, compares the beat stability threshold, and selects the beat stable section; The trend stability identification module extracts the spatial position coordinates of the corresponding frame points according to the beat stability paragraph, performs linear fitting and extracts the corresponding fitting slope, determines the continuous paragraph with the smallest fluctuation amplitude and extracts the frame index, and generates trend stability node index data; The motion information acquisition module obtains the three-dimensional position points of each frame of the main limb according to the trend stable node index data, calculates the sum of the path distance, constructs the direction vector and calculates the direction angle, and obtains the main limb motion information by combining the starting frame and the total number of frames; The synchronous reorganization execution module calculates the rotation angle and performs direction correction according to the main limb movement information, scales all frame time duration values ​​proportionally, rearranges the frame sequence to construct a new dynamic structure, and obtains the dynamic display result of the ethnic dance.

2. The digital folk dance display system according to claim 1 is characterized in that: The turning frame index sequence includes action change nodes, turning angle distribution, and action section boundaries; the beat stable section includes beat balance index, rhythm start and end information, and stability interval identification; the trend stable node index data includes stable trend reference frame, fitting change range, and rhythm trend parameters; the main limb movement information includes movement path characteristics, direction change parameters, and movement timing structure; the dynamic display results of the ethnic dance include reorganized action frame sequence, unified direction posture, and beat synchronization rhythm.

3. The digital display system of folk dance according to claim 1 is characterized in that: The trajectory node extraction module includes: The three-dimensional coordinate extraction submodule obtains the three-dimensional position coordinate data of the dancer's skeleton in each frame based on the video frame sequence of the continuous stepping action of the folk dance, extracts the three-dimensional coordinates of the dancer's foot joints in each frame in turn, organizes and stores them as a three-dimensional coordinate set sorted by frame order, and generates a three-dimensional coordinate sequence of the dance gait; The spatial vector construction submodule constructs two sets of spatial vectors according to the dance gait three-dimensional coordinate sequence and the coordinates of two adjacent gait trajectories between every three frames, calculates the angle value in each set of three frames, integrates the angle results between all three frames, and generates a spatial gait angle value sequence; The angle mutation judgment submodule uses the formula according to the spatial gait angle value sequence: ； Calculate the Frame angle value , according to the frame index whose angle mutation amplitude value is greater than the angle mutation threshold, extract and record the frame position, obtain and establish the turning frame index sequence, where, For the The space vector of the frame construction, is the module length, For the Frame foot key point distance, For the Frame timestamp, For the Frame angle mutation amplitude value, For the Frame angle mutation amplitude value, For the Frame foot key point distance, For the Frame timestamp.

4. The digital display system of folk dance according to claim 1 is characterized in that: The rhythm segment optimization module includes: The beat feature extraction submodule extracts the time interval between adjacent transition frames based on the transition frame index sequence to obtain the beat duration, calls the three-dimensional coordinate information in the corresponding frame to calculate the beat amplitude, and generates a rhythm segment beat feature sequence; The beat difference calculation submodule calculates the difference between the maximum and minimum values ​​of the beat duration set and amplitude set in each segment according to the beat feature sequence of the rhythm segment, using the formula: ； Calculate the Segment beat difference combination value , and obtain the beat difference combination value sequence, where , Respectively represent The maximum and minimum duration of the segment beat, , Respectively represent The maximum and minimum values ​​of the segment beat amplitude; The stable paragraph screening submodule determines whether the combination value in each rhythm segment is less than the beat stability threshold value according to the beat difference combination value sequence, screens all rhythm segments that meet the conditions, and establishes a beat stable paragraph.

5. The digital display system of folk dance according to claim 1 is characterized in that: The trend stability identification module includes: The coordinate extraction submodule extracts all frame indexes corresponding to each segment according to the stable beat segment, obtains the three-dimensional spatial position coordinates corresponding to the frame index, combines and records the coordinate sequences of each segment in chronological order, and generates stable segment spatial coordinate data; The trend fluctuation calculation submodule performs a linear fitting operation on the sequence of the three-dimensional spatial coordinates in each paragraph changing with time based on the stable paragraph spatial coordinate data, obtains the linear fitting slope value of each paragraph in the main time axis direction, compares the change intensity between all slope values, and establishes a composite calculation relationship between the slope change amount of adjacent paragraphs and the paragraph length, using the formula: ； Calculate the combined trend fluctuation value , extract the stable trend segment according to the continuous segment number interval with the smallest fluctuation value, and get the trend stable interval, where, For the The linear fitting slope value of the segment, For the The linear fitting slope value of the segment, For the The number of frames in the segment, From paragraph 1 to paragraph Segment accumulation operation, is the absolute value of the product of the slope value and the inverse segment length, Indicates the total number of segments; The node index generation submodule extracts all frame index sets in each stable segment according to the trend stable interval, calculates the median position according to the time position, extracts the corresponding frame index, and establishes trend stable node index data.

6. The digital display system of folk dance according to claim 1 is characterized in that: The action information collection module includes: The main limb coordinate extraction submodule extracts all frame indexes of the rhythm segment to which the node belongs according to the trend stable node index data, obtains the three-dimensional position coordinates of the main limb in each frame, and arranges them into a continuous coordinate sequence arranged in frame order to generate a main limb time series coordinate sequence; The motion path calculation submodule calculates the spatial distances between adjacent frame points in frame order based on the main limb temporal coordinate sequence, extracts the coordinate difference between the first frame and the last frame to represent the direction, and uses the formula: ； Calculate path direction combination value , revealing the total displacement and direction changes of the action, and obtaining the main limb space motion parameters, among which, For the Frame and The 3D distance between frames, , is the coordinate value of the main limb on the x-axis in the first frame and the last frame, is the total number of frames in the rhythm segment; The motion information construction submodule constructs and summarizes the corresponding structured fields according to the main limb spatial motion parameters, combined with the starting frame number and the number of frames of each segment, to establish the main limb motion information.

7. The digital display system of folk dance according to claim 1 is characterized in that: The synchronous reorganization execution module includes: The direction correction submodule traverses all frame points in the current rhythm segment frame by frame according to the main limb movement information, extracts the spatial direction vector of the main limb in each frame, calculates the angle difference between the current direction and the starting direction, and adjusts the direction vector of the current frame to maintain consistency with the initial direction, thereby generating a direction-consistent vector sequence; The time scaling submodule performs a proportional scaling operation on the time duration value corresponding to each frame based on the direction consistent vector sequence, and reallocates the new time point position corresponding to each frame according to the actual time length of the rhythm segment start time and the beat cycle to obtain a geometrically aligned time sequence; The structure rearrangement submodule rearranges the order of all frames in the rhythm segment according to the geometric alignment time sequence, and reconstructs the coordinates, direction and time label corresponding to each frame, and uniformly organizes them into continuous dynamic structure data to obtain the dynamic display result of the ethnic dance.

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