CN115937482B - Holographic scene dynamic construction method and system for self-adapting screen size - Google Patents
Holographic scene dynamic construction method and system for self-adapting screen size Download PDFInfo
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Abstract
The invention discloses a holographic scene dynamic construction method and system with a self-adaptive screen size, belongs to the field of mapping geographic information, and solves the problems of large detail loss and low frame rate of scene drawing in the holographic scene dynamic construction method in the prior art. The method comprises the steps of obtaining digital twin bridge construction scene data; the method comprises the steps of importing digital twin bridge construction scene data to construct a bridge construction holographic scene, and then dynamically constructing the self-adaptive screen size holographic scene based on the bridge construction holographic scene to obtain the position of a visual window drawing view of the bridge construction holographic scene, so as to obtain the bridge construction holographic scene with the self-adaptive screen size; optimizing the bridge construction holographic scene during interaction, and drawing the optimized bridge construction holographic scene based on the digital twin bridge construction scene data to obtain a drawn bridge construction holographic scene. The method is used for dynamically constructing the holographic scene.
Description
Technical Field
A method and a system for dynamically constructing a holographic scene with a self-adaptive screen size are used for dynamically constructing the holographic scene, and belong to the field of mapping geographic information.
Background
Bridges are used as key nodes and junction projects for interconnection and intercommunication of traffic facilities, and gradually extend to difficult mountain areas. And the factors such as complicated topography geological conditions in mountain areas, frequent mountain disasters, severe meteorological conditions and the like bring great challenges to bridge construction technology and engineering quality. In the important strategic background of informatization, along with the rapid development of industrial technology and new generation information technology, the bridge construction process in the hard mountain area should be deeply fused with the modern information technology, and the construction of increasingly intelligent construction systems and refined management modes are important development directions in the future of bridge construction. The bridge construction condition in the mountain area is bad, the period is long, the control difficulty is high, the influence of geological disasters such as landslide and debris flow at the poor geology position, the influence of mountain area canyon wind, sunshine, temperature difference and the like on the construction is also required to be considered, the construction is various in component types and complex in assembly process, and in addition, different construction sequences lead to different bridge stress states to influence the stability of the bridge structure. Therefore, how to consider the comprehensive influence of the surrounding geographic environment on bridge construction and develop digital simulation of the whole bridge construction process in a difficult environment is a key scientific problem which needs to be solved urgently.
The digital twin technology is used as a key application technology for solving the difficult interaction problem of a digital model and a physical entity and trampling the digital transformation concept and the target, and plays an important role in the realization of digital simulation and simulation in the whole bridge construction process. At present, research and application of a digital twin model in bridge engineering are still in a starting stage, and most of current research focuses on digital twin concept abstraction and specific engineering application. The research focus of the digital twin bridge construction simulation at the present stage is to build a three-dimensional visual model of physical entities (bridges and surrounding scenes) with high fidelity so as to provide a three-dimensional visual operation platform for subsequent applications. The virtual geographic environment and the building information model are key methods for constructing the platform.
Holographic projection technology is considered as one of the best three-dimensional visualization means by virtue of the advantage of comprehensively presenting three-dimensional object effects and displaying the picture contents in an omnibearing and three-dimensional manner. The hologram provides a three-dimensional visualization means for digital twinning by virtue of a unique display effect. Compared with the traditional three-dimensional visualization means or head-mounted VR based on the screen, the holographic visualization technology has the advantages that a user can conveniently observe multi-angle and multi-azimuth three-dimensional scenes through naked eyes without other equipment, a novel visualization and interaction means are provided for centralized research and judgment of multiple people, and the requirements of digital twin real-time research and timely feedback are met. At present, the holographic projection technology is mainly applied to the fields of education, games, military, industry, cultural relics display, medicine and the like. In contrast, holographic technology has less application in digital twinning, particularly in bridge construction and construction. In the prior art, the holographic technology is applied to digital twinning, and the following technical problems exist:
1. The dynamic construction method of the holographic scene in the prior art has the defects of larger detail loss and low frame rate of scene drawing.
2. The holographic video source is required to be prefabricated, the holographic display is performed by adapting to the screen size, and the problem of poor holographic display effect is caused.
Disclosure of Invention
The invention aims to provide a holographic scene dynamic construction method and a holographic scene dynamic construction system with self-adaptive screen size, which solve the problems of larger detail loss and low frame rate of scene drawing in the holographic scene dynamic construction method in the prior art.
In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:
a method for dynamically constructing a holographic scene with a self-adaptive screen size comprises the following steps:
step 1, obtaining digital twin bridge construction scene data;
step 2, importing digital twin bridge construction scene data to construct a bridge construction holographic scene, and then dynamically constructing the self-adaptive screen size holographic scene based on the bridge construction holographic scene to obtain the position of a visual window drawing view of the bridge construction holographic scene, so as to obtain the bridge construction holographic scene with the self-adaptive screen size;
and 3, optimizing the bridge construction holographic scene obtained in the step 2 during interaction, and drawing the optimized bridge construction holographic scene based on the digital twin bridge construction scene data to obtain a drawn bridge construction holographic scene.
Further, the digital twin bridge construction scene data in the step 1 includes digital elevation, thematic data, bridge BIM model of the bridge entity part, inclination data, monitoring data, management data and geographic information data, wherein the digital elevation includes topography, thematic data includes river, vegetation, road, ground and measurement data, the bridge BIM data includes building information model of bridge deck, pier, suspension rope and bridge span of the bridge, the inclination data includes topography, ground, river, tree and building digital surface model, the monitoring data includes bridge construction stage monitoring data, wind field monitoring data, temperature field monitoring data, bridge stress field monitoring data in the construction scene, the management data includes bridge part attribute and bridge construction progress, and the geographic information data includes image, topography, road, river and building.
Further, the specific steps of the step 2 are as follows:
step 2.1, importing digital twin bridge construction scene data to construct a bridge construction holographic scene, arranging four virtual cameras for rendering and drawing the scene in real time in the bridge construction holographic scene based on the bridge construction holographic scene, and constructing a linkage window based on the four virtual cameras, namely, the four virtual cameras are always aligned to a unified area in the same action, wherein the bridge construction holographic scene is a virtual scene of bridge construction;
And 2.2, performing self-adaptive screen size picture segmentation and dynamic layout based on a pepper's theory, a holographic projection imaging theory and a linkage window, and obtaining the position of a visual window drawing view of the bridge construction holographic scene after the dynamic layout, thereby obtaining the bridge construction holographic scene with the self-adaptive screen size.
Further, the specific steps of the step 2.1 are as follows:
step 2.11, importing digital twin bridge construction scene data to construct a bridge construction holographic scene, arranging four virtual cameras for rendering and drawing the scene in real time in the bridge construction holographic scene based on the bridge construction holographic scene, taking the plane where the four virtual cameras are positioned as an XY axis, taking the direction vertical to the XY axis as a Z axis, taking the center of the bridge construction holographic scene as an origin, establishing a coordinate system, and calculating to obtain a transformation relation between the virtual cameras so as to enable the cameras in the bridge construction holographic scene to aim at the same object in the same posture, wherein the transformation relation between the virtual cameras comprises translation, scaling and rotation between every two virtual cameras, and the translation refers to displacement of the virtual cameras in the bridge construction holographic scene, and then the displacement of the other three virtual cameras with the same dimension is carried out;
Let the distance from each virtual camera to the origin be l 0 Moving the bridge construction holographic scene to a point (x 0 ，y 0 ，z 0 ) The rotation of the virtual camera in the Y-axis direction is transformed into:
in the Y-axis direction, the scaling of the virtual camera is:
wherein y 0 |≤l 0 ；
The rotation of the virtual camera in the X-axis direction is transformed as follows:
in the X-axis direction, the scaling of the virtual camera is:
wherein, |x 0 |≤l 0 ；
Wherein alpha is y Euler angle, beta, around y-axis for a virtual camera coordinate system z Is the rotation angle alpha of the coordinate system around the z axis after the virtual camera rotates z Euler angle, x, around z-axis for a virtual camera coordinate system 0 Building a distance, y, of a holographic scene moving in the x-axis direction for a bridge 0 Building a distance z by which a holographic scene moves in the y-axis direction for a bridge 0 Building a distance for the bridge, in which the holographic scene moves in the z-axis direction;
and 2.12, adjusting each virtual camera based on the transformation relation among the virtual cameras to obtain a linkage window, namely, uniformly linkage four virtual cameras.
Further, the specific steps of the step 2.2 are as follows:
2.21, defining four vertex coordinates of the screen as a (0, 0), b (0, n), c (m, 0) and d ((m, n) respectively based on a holographic projection imaging principle, wherein m and n are resolutions of the screen, and determining a central o coordinate of the screen as (m/2, n/2), so that a built holographic picture is always at the center of the picture and accords with the imaging principle of holographic projection, and a square with a side length of n is built by taking a point o as the center, wherein four vertexes of the square are a '(m/2-n/2, 0), b' (m/2-n/2, n), c '(m/2+n/2, 0) and d' (m/2+n/2, n) respectively, and performing self-adaptive screen size picture segmentation based on the four vertexes of the square to obtain a holographic picture imaging area;
Step 2.22, dynamically laying out four visual windows dynamically generated by four virtual cameras based on the holographic picture imaging area, and obtaining the positions of visual window drawing views of the bridge construction holographic scene after dynamic layout, wherein the four visual windows are the linkage windows obtained in the step 2.12;
when the maximum value of the frame range after dynamic layout is obtained according to the holographic projection imaging principle, the bottom edge length is as follows:
L＝w+2h (4)
h/w=n/m, then there is
Wherein w is the width of the visual window, and h is the height of the visual window;
after dynamic layout, the front view positions of the visual window drawing are as follows:
the rear view positions are:
the left view position is:
the right view position is:
further, the specific steps of the step 3 are as follows:
step 3.1, optimizing a bridge construction holographic scene during interaction;
and 3.2, rendering and drawing the bridge construction holographic scene in real time based on the digital twin bridge construction scene data loaded in the digital twin platform by the optimized bridge construction holographic scene, and obtaining the drawn bridge construction holographic scene.
Further, the specific steps of the step 3.1 are as follows:
step 3.11, obtaining a fuzzy range of an object in each visual window during interaction, namely a fuzzy region, wherein the fuzzy region comprises a fuzzy region generated by linear motion fuzzy and rotary motion fuzzy, and the fuzzy degree is obtained by calculating a point spread function of the linear motion fuzzy and the rotary motion fuzzy, and the interaction comprises movement, rotation and scaling;
And 3.12, simplifying the fuzzy area by adopting a simplifying means, namely reducing the data precision, obtaining a simplified bridge construction holographic scene, namely obtaining an optimized bridge construction holographic scene during interaction, wherein the simplifying means comprises network simplification or texture compression.
Further, in the step 3.11:
the point spread function of the linear motion blur comprises two parameters of total displacement and motion direction, the blurred image g (x, y) is formed by the linear motion of the original image f (x, y) in the direction forming an alpha angle with the x axis, and then the value of any point of the blurred image is as follows:
where g (x, y) is the value of any point of the blurred image, x 0 (t) is the motion component of the holographic scene for bridge construction in the x direction at the moment t, y 0 (T) is the motion component of the holographic scene for bridge construction in the y direction at the moment T, and if the total displacement of the object is a, the total time is T m The rate of movement is Then there are:
the discretization of the equation 12 obtains a blurred region of linear motion blur, and the equation is:
wherein L' is the number of pixels of the bridge construction holographic scene moving, i.e. the fuzzy scale, i is the ith pixel, u= [ i cos alpha ], v= [ i sin alpha ], and alpha represents the motion direction;
the calculation of the fuzzy region by convolution operation can be:
g(x，y)＝f(x，y).h(u，v)
Wherein (u, v) is a point spread function:
the rotational motion blur is different from the linear motion blur, is a spatially variable motion blur, has different blur parameters on different blur paths, and has larger blur scale as the rotational center is far away; the degree of blurring of points at the same position from the rotation center is the same, i.e. the degree of blurring of images on the same ring is the same, while the rotation motion blurring is distributed along different rotation paths;
assuming that the rotation center is the origin (0, 0), the distance between any pixel point i (x, y) in the blurred image g (x, y) and the rotation center isLet the rotation time of the object be T s When the rotational angular velocity is ω, the relationship between the blurred image g (x, y) and the original image f (x, y) is:
represented in polar vertex form:
wherein r represents a radial coordinate, represents a distance from an origin to i (x, y), θ represents an angular coordinate, represents a positive x-axis at a start edge, and represents an included angle between rays passing through the origin and i (x, y) at an end point;
let l=r, θ, s=rωt, r is denoted as subscript, h r As the point spread function, the point spread function at the point where any pixel point i (x, y) is r from the rotation center length is h r (i) Then:
wherein the method comprises the steps of
The discrete processing of equation 16 yields a blurred region of rotational motion blur, which can be:
wherein i=0, 1,2, N r -1，g r (i) And f r (i) Respectively a blurred pixel value and an original gray value of an ith pixel point on a blurred path, N r Represents the number of pixel points, and L r The pixel number is used for representing the fuzzy scale;
the point spread function in the form of a rotational motion blur matrix is derived based on equation 17 as:
a holographic scene dynamic construction system that adapts to screen size, comprising:
the acquisition module is used for: acquiring digital twin bridge construction scene data;
and a dynamic construction module: the method comprises the steps of importing digital twin bridge construction scene data to construct a bridge construction holographic scene, and then dynamically constructing the self-adaptive screen size holographic scene based on the bridge construction holographic scene to obtain the position of a visual window drawing view of the bridge construction holographic scene, so as to obtain the bridge construction holographic scene with the self-adaptive screen size;
and a drawing module: and during interaction, optimizing the bridge construction holographic scene obtained by the dynamic construction module, and drawing the optimized bridge construction holographic scene based on the digital twin bridge construction scene data to obtain a drawn bridge construction holographic scene.
Further, the specific implementation steps of the dynamic construction module are as follows:
2.1, constructing a digital twin bridge construction scene based on digital twin bridge construction scene data to obtain a bridge construction holographic scene, arranging four virtual cameras for rendering and drawing the scene in real time in the bridge construction holographic scene, and constructing a linkage window based on the four virtual cameras, namely, enabling the four virtual cameras to always aim at a unified area in the same action, wherein the bridge construction holographic scene is a virtual scene of bridge construction;
step 2.2, performing self-adaptive screen size picture segmentation and dynamic layout based on a pepper's theory, a holographic projection imaging theory and a linkage window, and obtaining the position of a visual window drawing view of the bridge construction holographic scene after the dynamic layout, thereby obtaining the bridge construction holographic scene with the self-adaptive screen size;
the specific implementation steps of the drawing module are as follows:
step 3.1, optimizing a bridge construction holographic scene during interaction;
and 3.2, rendering and drawing the bridge construction holographic scene in real time based on the digital twin bridge construction scene data loaded in the digital twin platform by the optimized bridge construction holographic scene, and obtaining the drawn bridge construction holographic scene.
Compared with the prior art, the invention has the advantages that:
1. the method can realize real-time construction of the bridge construction holographic scene with the self-adaptive screen in different sizes, and the provided optimization method can reduce the scene drawing data by about 30-45% on the premise of ensuring small detail loss, thereby remarkably improving the frame rate.
2. According to the invention, a motion blur algorithm is applied, a blur range of a scene caused by taking motion time, motion direction and the like as related parameters in motion is calculated, a model with low distribution precision of the range of current blur is given, and data with higher precision is distributed at a place where no blur appears, so that the loading pressure of the data is reduced, the drawing efficiency is improved, namely, the blur range of an object in a holographic scene built by a bridge in interaction can be obtained by calculating linear motion blur and rotational motion blur, namely, a blur area is obtained, and fewer resources are distributed to the blur area through a corresponding point spread function to reduce resolution ratio and render, and the centralized rendering can reduce the rendered data, improve the drawing efficiency and reduce the dizziness feeling when user experience is experienced on the premise of guaranteeing high-fidelity rendering of important areas in the holographic scene built by the bridge;
3. The method can dynamically construct the bridge construction holographic scene in real time without preparing a holographic video source in advance, and the holographic display is carried out by adapting to the size of the screen, so that the holographic display effect is good.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present invention and should not be considered limiting the scope, and that other related drawings can be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of a frame of the present invention;
FIG. 2 is a schematic diagram of a framework for dynamic construction of a self-adaptive screen-size holographic scene in the present invention;
FIG. 3 is a schematic representation of holographic imaging region segmentation in accordance with the present invention;
FIG. 4 is a schematic diagram of a software and hardware configuration table according to an embodiment of the present invention;
FIG. 5 is a schematic diagram of a generic system interface in an embodiment of the invention;
FIG. 6 is a schematic diagram of experimental results and analysis of a self-adaptive screen size holographic scene construction in an embodiment of the invention;
FIG. 7 shows the holographic self-construction and visualization effects at 1920 x 1080 resolution, (a) the self-construction map, and (b) the visualization effects according to the present invention;
Fig. 8 shows the holographic auto-construction and visualization effects at 1920 x 1200 resolution, (a) auto-construction map, and (b) visualization effects according to an embodiment of the present invention;
FIG. 9 shows the self-construction and visualization effects of a hologram at 1680 x 1050 resolution, (a) is an auto-construction map, and (b) is a visualization effect, according to an embodiment of the present invention;
FIG. 10 shows the self-construction and visualization effects of a hologram at 1440 x 1050 resolution, (a) is an auto-construction map, and (b) is a visualization effect, according to an embodiment of the present invention;
FIG. 11 is a graph comparing efficiency of scene rendering before and after optimization in accordance with an embodiment of the present invention;
FIG. 12 is a scene rendering diagram of an embodiment of the invention, wherein (a) is an optimized front view scene, (b) is a view scene after linear motion blur, (c) is an optimized front view scene (d) is a view scene after rotational motion blur;
FIG. 13 is a diagram of recording the current holographic scene rendering frame rate and the number of triangles rendered in the scene every 1s in an embodiment of the present invention.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Aiming at the problems, the real-time visualization research work of the holographic scene is carried out, a holographic scene dynamic construction method of the self-adaptive screen size is provided, the holographic image dynamic construction of the self-adaptive screen size is carried out through linkage of four cameras according to the holographic imaging principle, the real-time visualization of the bridge construction holographic scene is realized, the visual characteristics of eyes are considered on the basis, the scene visualization efficiency is optimized based on a motion blur algorithm, the scene drawing efficiency is improved, and the high-efficiency rendering of the bridge construction scene is realized.
A method for dynamically constructing a holographic scene with a self-adaptive screen size comprises the following steps:
step 1, obtaining digital twin bridge construction scene data; the digital twin bridge construction scene data comprises digital elevation, thematic data, bridge BIM model of the bridge entity component, inclination data, monitoring data, management data and geographic information data, wherein the digital elevation comprises topography, the thematic data comprises river, vegetation, roads, ground objects and measurement data, the bridge BIM data comprises building information model of bridge deck, pier, suspension cable and bridge span of a large bridge, the inclination data comprises topography, ground objects, rivers, trees and building digital surface model, the monitoring data comprises bridge construction stage monitoring data, wind field monitoring data in the construction scene, temperature field monitoring data and bridge stress field monitoring data, the management data comprises bridge component attribute and bridge construction progress, and the geographic information data comprises images, topography, roads, rivers and buildings. In practice, data for other scenarios is also possible.
Step 2, importing digital twin bridge construction scene data to construct a bridge construction holographic scene, and then dynamically constructing the self-adaptive screen size holographic scene based on the bridge construction holographic scene to obtain the position of a visual window drawing view of the bridge construction holographic scene, so as to obtain the bridge construction holographic scene with the self-adaptive screen size; the method comprises the following specific steps:
step 2.1, importing digital twin bridge construction scene data to construct a bridge construction holographic scene, arranging four virtual cameras for rendering and drawing the scene in real time in the bridge construction holographic scene based on the bridge construction holographic scene, and constructing a linkage window based on the four virtual cameras, namely, the four virtual cameras are always aligned to a unified area in the same action, wherein the bridge construction holographic scene is a virtual scene of bridge construction; the method comprises the following specific steps:
step 2.11, importing digital twin bridge construction scene data to construct a bridge construction holographic scene, arranging four virtual cameras for rendering and drawing the scene in real time in the bridge construction holographic scene based on the bridge construction holographic scene, taking the plane where the four virtual cameras are positioned as an XY axis, taking the direction vertical to the XY axis as a Z axis, taking the center of the bridge construction holographic scene as an origin, establishing a coordinate system, and calculating to obtain a transformation relation between the virtual cameras so as to enable the cameras in the bridge construction holographic scene to aim at the same object in the same posture, wherein the transformation relation between the virtual cameras comprises translation, scaling and rotation between every two virtual cameras, and the translation refers to displacement of the virtual cameras in the bridge construction holographic scene, and then the displacement of the other three virtual cameras with the same dimension is carried out;
Let the distance from each virtual camera to the origin be l 0 Moving the bridge construction holographic scene to a point (x 0 ，y 0 ，z 0 ) The rotation of the virtual camera in the Y-axis direction is transformed into:
in the Y-axis direction, the scaling of the virtual camera is:
wherein y 0 |≤l 0 ；
The rotation of the virtual camera in the X-axis direction is transformed as follows:
in the X-axis direction, the scaling of the virtual camera is:
wherein, |x 0 |≤l 0 ；
Wherein alpha is y Euler angle, beta, around y-axis for a virtual camera coordinate system z Is the rotation angle alpha of the coordinate system around the z axis after the virtual camera rotates z Euler angle, x, around z-axis for a virtual camera coordinate system 0 Building a distance, y, of a holographic scene moving in the x-axis direction for a bridge 0 Building a distance z by which a holographic scene moves in the y-axis direction for a bridge 0 Building a distance for a holographic scene to move in the z-axis direction for a bridge；
And 2.12, adjusting each virtual camera based on the transformation relation among the virtual cameras to obtain a linkage window, namely, uniformly linkage four virtual cameras.
And 2.2, performing self-adaptive screen size picture segmentation and dynamic layout on the basis of a pepper's theory, a holographic projection imaging theory (namely holographic imaging characteristics described in a finger chart) and a linkage window, and obtaining the position of a visual window drawing view of the bridge construction holographic scene after dynamic layout, so as to obtain the bridge construction holographic scene with the self-adaptive screen size. The method comprises the following specific steps:
2.21, defining four vertex coordinates of the screen as a (0, 0), b (0, n), c (m, 0) and d ((m, n) respectively based on a holographic projection imaging principle, wherein m and n are resolutions of the screen, and determining a central o coordinate of the screen as (m/2, n/2), so that a built holographic picture is always at the center of the picture and accords with the imaging principle of holographic projection, and a square with a side length of n is built by taking a point o as the center, wherein four vertexes of the square are a '(m/2-n/2, 0), b' (m/2-n/2, n), c '(m/2+n/2, 0) and d' (m/2+n/2, n) respectively, and performing self-adaptive screen size picture segmentation based on the four vertexes of the square to obtain a holographic picture imaging area;
step 2.22, dynamically laying out four visual windows dynamically generated by four virtual cameras based on the holographic picture imaging area, and obtaining the positions of visual window drawing views of the bridge construction holographic scene after dynamic layout, wherein the four visual windows are the linkage windows obtained in the step 2.12;
when the maximum value of the frame range after dynamic layout is obtained according to the holographic projection imaging principle, the bottom edge length is as follows:
L＝w+2h (4)
h/w=n/m, then there is
Wherein w is the width of the visual window, and h is the height of the visual window;
After dynamic layout, the front view positions of the visual window drawing are as follows:
the rear view positions are:
the left view position is:
the right view position is:
the method takes the principle of holographic technology into consideration, dynamically constructs a visual window with self-adaptive screen resolution and reasonably and dynamically distributes the visual window according to the characteristics of holographic imaging so as to achieve real-time holographic effect visual display of the self-adaptive screen size.
And 3, optimizing the bridge construction holographic scene obtained in the step 2 during interaction, and drawing the optimized bridge construction holographic scene based on the digital twin bridge construction scene data to obtain a drawn bridge construction holographic scene.
The method comprises the following specific steps:
step 3.1, optimizing a bridge construction holographic scene during interaction; the method comprises the following specific steps:
step 3.11, obtaining a fuzzy range, namely a fuzzy area, of an object in each visual window during interaction, wherein the fuzzy area comprises a fuzzy area generated by linear motion fuzzy and rotary motion fuzzy, and the fuzzy degree is obtained through a point spread function of the linear motion fuzzy and the rotary motion fuzzy, and the interaction comprises movement, rotation and scaling;
persistence of vision is a phenomenon in which light generated from the retina ceases to act for a period of time. When an object moves rapidly, after the image seen by the human eye disappears, the impression of the visual nerve on the object does not disappear immediately due to the phenomenon of visual persistence, but a scene (Jiang Wenjie and the like 2015) of motion blur seen by the human eye is formed for a long time, and the transient motion of the holographic scene during construction interaction and even display can cause motion blur. Meanwhile, the dynamic construction of the holographic scene is simultaneously rendered by four virtual cameras, and compared with a single virtual camera, the construction of the holographic scene inevitably causes huge pressure on rendering. Considering that holographic scene exploration interaction is a human body, the physiological characteristics and psychological needs of people are required to be combined, an optimization method suitable for constructing the holographic scene by the bridge is designed, the drawing efficiency of the scene is further improved, and meanwhile, dizziness caused by exploration and analysis of a user is reduced.
In the holographic scene for bridge construction, the bridge main body is positioned in the central area of the scene, and the edges of the holographic scene for bridge construction are mostly terrains, rivers, sky and the like related to the bridge. Therefore, the bridge is taken as a central position, namely the position aligned by the camera in the holographic scene of bridge construction, the design algorithm calculates a motion blur area formed by taking the bridge as the center, and less resources are allocated to the blur area to reduce resolution rendering, so that rendering data can be greatly reduced, and meanwhile, loss of perceived details is reduced to the minimum.
In the holographic scene of bridge construction, the state of the scene when the human eyes observe the scene is simulated by aiming at the scene object in real time through a virtual camera. The point spread function of the linear motion blur comprises two parameters of total displacement and motion direction, the blurred image g (x, y) is formed by the linear motion of the original image f (x, y) in the direction forming an alpha angle with the x axis, and then the value of any point of the blurred image is as follows:
where g (x, y) is the value of any point of the blurred image, x 0 (t) is the motion component of the holographic scene for bridge construction in the x direction at the moment t, y 0 (T) is the motion component of the holographic scene for bridge construction in the y direction at the moment T, and if the total displacement of the object is a, the total time is T m The rate of movement is Then there are:
the discretization of the equation 12 obtains a blurred region of linear motion blur, and the equation is:
wherein L' is the number of pixels of the bridge construction holographic scene moving, i.e. the fuzzy scale, i is the ith pixel, u= [ i cos alpha ], v= [ i sin alpha ], and alpha represents the motion direction;
the calculation of the fuzzy region by convolution operation can be:
g(x，y)＝f(x，y).h(u，v)
wherein (u, v) is a point spread function:
the rotational motion blur is different from the linear motion blur, is a spatially variable motion blur, has different blur parameters on different blur paths, and has larger blur scale as the rotational center is far away; the degree of blurring of points at the same position from the rotation center is the same, i.e. the degree of blurring of images on the same ring is the same, while the rotation motion blurring is distributed along different rotation paths;
assuming that the rotation center is the origin (0, 0), the distance between any pixel point i (x, y) in the blurred image g (x, y) and the rotation center isLet the rotation time of the object be T s When the rotational angular velocity is ω, the relationship between the blurred image g (x, y) and the original image f (x, y) is:
represented in polar vertex form:
wherein r represents a radial coordinate, represents a distance from an origin to i (x, y), θ represents an angular coordinate, represents a positive x-axis at a start edge, and represents an included angle between rays passing through the origin and i (x, y) at an end point;
Let l=r, θ, s=rωt, r is denoted as subscript, h r As the point spread function, the point spread function at the point where any pixel point i (x, y) is r from the rotation center length is h r (i) Then:
wherein the method comprises the steps of
The discrete processing of equation 16 yields a blurred region of rotational motion blur, which can be:
wherein i=0, 1,2, N r -1，g r (i) And f r (i) Respectively a blurred pixel value and an original gray value of an ith pixel point on a blurred path, N r Represents the number of pixel points, and L r The pixel number is used for representing the fuzzy scale;
the point spread function in the form of a rotational motion blur matrix is derived based on equation 17 as:
and 3.12, simplifying the fuzzy area by adopting a simplifying means, namely reducing the data precision, obtaining a simplified bridge construction holographic scene, namely obtaining an optimized bridge construction holographic scene during interaction, wherein the simplifying means comprises network simplification or texture compression.
And 3.2, rendering and drawing the bridge construction holographic scene in real time based on the digital twin bridge construction scene data loaded in the digital twin platform by the optimized bridge construction holographic scene, and obtaining the drawn bridge construction holographic scene.
Examples
The selected case area is located in a large bridge construction scene of Luding county (101 DEG 46 '-102 DEG 25',29 DEG 54 '-30 DEG 10') in Ganzi Tibetan autonomous state of Sichuan province, is used as a case and is subjected to experimental analysis, and the area range comprises elements such as bridges, buildings, rivers, hills and the like. The accuracy of the research party is evaluated from the two angles of real-time construction efficiency and scene rendering efficiency of the holographic scene.
The system prototype research and development environment configuration is based on the development environment, a digital twin-driven bridge construction holographic scene interaction and query analysis system is developed, and as shown in fig. 4, a system main interface is provided, and main functions comprise bridge construction holographic scene visualization, optimization drawing, project introduction, bridge component attribute query and bridge progress simulation.
The dynamic construction of the holographic scene (bridge construction holographic scene) can be measured by two indexes of the holographic scene rendering frame rate and the holographic picture construction effect under different screen resolutions. The rendering time between each frame of pictures of the holographic scene reflects the real-time efficiency of scene construction, and also determines the experience of the user on the holographic scene. After the data is accessed, recording the holographic scene construction time of different screen resolutions. The experimental results are shown in FIG. 6.
The research surface shows that the visual frame number of human eyes is 24 frames per second to 30 frames per second, the average construction time of each frame of picture of the holographic scene is 15.48ms under different screen resolutions in the whole test process, the average rendering efficiency is 65.46fps, the minimum of capturing pictures per second of human eyes is reached, and the smooth rendering and real-time construction of the holographic scene can be ensured.
And by the self-adaptive screen visual holographic scene construction method, the dynamic construction of holographic pictures can be carried out aiming at display terminals with different screen size resolutions, and visual display can be carried out. Experiments prove that the method provided by the invention can realize the visualization of holographic scenes with different screen size resolutions, and smooth rendering and real-time construction of the holographic scene pictures. Specifically, fig. 7 shows the self-priming and visualization effects at 1920×1080 resolution, fig. 8 shows the self-priming and visualization effects at 1920×1200 resolution, fig. 9 shows the self-priming and visualization effects at 1680×1050 resolution, and fig. 10 shows the self-priming and visualization effects at 1440×1050 resolution.
The scene rendering optimization is the key for reducing the dizziness of users and improving the interactive experience, and can effectively support the interactive exploration and query analysis of the holographic scene of bridge construction by users, so that the analysis of the scene drawing efficiency before and after the optimization is particularly important, and is particularly shown in fig. 11.
Fig. 12 is an analysis of the drawing data amount of a holographic scene for bridge construction, the scheme randomly extracts 15 moments when a user performs interactive browsing in the scene, and the triangular surface required to be drawn by the scene rendering optimization method based on motion blur is reduced by about 30% -45% compared with the original scene.
Recording the current holographic scene rendering frame rate and the number of triangles rendered in the scene every 1 s. The experimental results are shown in FIG. 13.
The average rendering frame rate in the whole test process after optimization is 77.79 frames, the rendering efficiency after optimization is improved by about 17.7% compared with that before optimization, and the difference between the frame rate of an experimental group and the frame rate of a control group has statistical significance (4.28E-15 < 0.05). The standard deviation of the experimental group is 9.57, and the standard deviation of the control group is 11.85, which reflects that the frame rate stability of the experimental group is superior to that of the control group. The improvement of the frame rate is mainly because if the frame rate is judged according to the fuzzy area, the data precision is reduced by adopting means such as grid simplification, texture compression and the like for complex scene contrast images in the fuzzy area, the scene data is greatly reduced on the premise of ensuring that the important area is high and the rendering is ensured, and the rendering efficiency is improved. The later data in the experimental process are mainly bridge data, and different from the mountain land data in the prior experimental process, the building data have more vertexes and triangular faces in the same area, so that the rendering frame rate of the experimental group and the control group is reduced after 80 seconds. According to the Pearson correlation coefficient calculation method, the correlation coefficient of the experimental framing rate and the triangular surface number is-0.89, and the correlation coefficient of the frame rate and the triangular surface number of the comparison group is-0.91, so that the rendering frame rate and the triangular surface number are in negative correlation. Rendering efficiency increases when the triangle surface in the scene decreases.
Aiming at the problems that most of holographic scenes are static display, a holographic video source is prefabricated and cannot be displayed in real time at present, the method for dynamically constructing the holographic scenes with the self-adaptive screen size is provided. According to the Peperot principle, the dynamic picture layout of the self-adaptive screen size is achieved through the linkage of the four cameras, and the holographic picture dynamic construction of the bridge construction scene is realized; on the basis, the visual characteristics of human eyes are considered, and the scene visualization efficiency is optimized based on a motion blur algorithm so as to improve the scene drawing efficiency. Based on the method, a prototype system is constructed in an experimental area to perform experiments. Experiments show that the self-adaptive screen size holographic scene dynamic construction method provided by the invention can dynamically construct holographic pictures aiming at display terminals with different screen size resolutions, and the holographic scene optimization method provided by the invention can enable the average rendering frame rate of the holographic scene to reach 77.79 frames per second, compared with the rendering efficiency before optimization, the rendering efficiency is improved by about 17.7%, the triangular surface to be drawn is reduced by about 30% -45% compared with the original scene, and picture jamming and tearing are rarely generated for rendering a large amount of scene data burst in the holographic scene, so that the user experience of the holographic scene is greatly improved. The method can realize efficient rendering and displaying of the digital twin holographic scene for bridge construction.
In summary, the visual display of the bridge construction scene twinning system is performed in a holographic projection mode; the holographic projection is mostly used for still display, so that holographic video sources are mostly manufactured in advance, the functions of real-time performance and dynamic display are lacked, the display of real-time dynamic holographic projection is realized, and besides, the design algorithm realizes the dynamic construction of holographic scenes with self-adaptive screen sizes; and according to the human eye visual characteristics, an algorithm is designed to optimize the scene data loading rate/the scene drawing rendering efficiency.
Although the above research has made some progress, there is still a great room for improvement, and the interactive application in the current holographic scene is weak, and in the subsequent research work, the gesture recognition interactive device is combined, and the user is supported to browse and query in the bridge construction scene in a gesture interaction mode. The natural gesture interaction mode can reduce the man-machine interaction learning cost of the user and improve the cognitive efficiency of the user.
Claims (3)
1. A method for dynamically constructing a holographic scene with a self-adaptive screen size is characterized by comprising the following steps:
step 1, obtaining digital twin bridge construction scene data;
Step 2, importing digital twin bridge construction scene data to construct a bridge construction holographic scene, and then dynamically constructing the self-adaptive screen size holographic scene based on the bridge construction holographic scene to obtain the position of a visual window drawing view of the bridge construction holographic scene, so as to obtain the bridge construction holographic scene with the self-adaptive screen size;
the specific steps of the step 2 are as follows:
step 2.1, importing digital twin bridge construction scene data to construct a bridge construction holographic scene, arranging four virtual cameras for rendering and drawing the scene in real time in the bridge construction holographic scene based on the bridge construction holographic scene, and constructing a linkage window based on the four virtual cameras, namely, the four virtual cameras are always aligned to a unified area in the same action, wherein the bridge construction holographic scene is a virtual scene of bridge construction;
step 2.2, performing self-adaptive screen size picture segmentation and dynamic layout based on a pepper's theory, a holographic projection imaging theory and a linkage window, and obtaining the position of a visual window drawing view of the bridge construction holographic scene after the dynamic layout, thereby obtaining the bridge construction holographic scene with the self-adaptive screen size;
the specific steps of the step 2.1 are as follows:
Step 2.11, importing digital twin bridge construction scene data to construct a bridge construction holographic scene, arranging four virtual cameras for rendering and drawing the scene in real time in the bridge construction holographic scene based on the bridge construction holographic scene, taking the plane where the four virtual cameras are positioned as an XY axis, taking the direction vertical to the XY axis as a Z axis, taking the center of the bridge construction holographic scene as an origin, establishing a coordinate system, and calculating to obtain a transformation relation between the virtual cameras so as to enable the cameras in the bridge construction holographic scene to aim at the same object in the same posture, wherein the transformation relation between the virtual cameras comprises translation, scaling and rotation between every two virtual cameras, and the translation refers to displacement of the virtual cameras in the bridge construction holographic scene, and then the displacement of the other three virtual cameras with the same dimension is carried out;
let the distance from each virtual camera to the origin be l 0 Moving the bridge construction holographic scene to a point (x 0 ,y 0 ,z 0 ) Then the Y axis directionThe rotation of the virtual camera above is transformed into:
in the Y-axis direction, the scaling of the virtual camera is:
wherein y 0 |≤l 0 ；
The rotation of the virtual camera in the X-axis direction is transformed as follows:
in the X-axis direction, the scaling of the virtual camera is:
Wherein, |x 0 |≤l 0 ；
Wherein alpha is y Euler angle, beta, around y-axis for a virtual camera coordinate system z Is the rotation angle alpha of the coordinate system around the z axis after the virtual camera rotates z Euler angle, x, around z-axis for a virtual camera coordinate system 0 Building a distance, y, of a holographic scene moving in the x-axis direction for a bridge 0 Building a distance z by which a holographic scene moves in the y-axis direction for a bridge 0 Building a distance for the bridge, in which the holographic scene moves in the z-axis direction;
step 2.12, adjusting each virtual camera based on the transformation relation among the virtual cameras to obtain a linkage window, namely, uniformly linkage of the four virtual cameras;
the specific steps of the step 2.2 are as follows:
2.21, defining four vertex coordinates of the screen as a (0, 0), b (0, n), c (m, 0) and d ((m, n) respectively based on a holographic projection imaging principle, wherein m and n are resolutions of the screen, and determining a central o coordinate of the screen as (m/2, n/2), so that a built holographic picture is always at the center of the picture and accords with the imaging principle of holographic projection, and a square with a side length of n is built by taking a point o as the center, wherein four vertexes of the square are a '(m/2-n/2, 0), b' (m/2-n/2, n), c '(m/2+n/2, 0) and d' (m/2+n/2, n) respectively, and performing self-adaptive screen size picture segmentation based on the four vertexes of the square to obtain a holographic picture imaging area;
Step 2.22, dynamically laying out four visual windows dynamically generated by four virtual cameras based on the holographic picture imaging area, and obtaining the positions of visual window drawing views of the bridge construction holographic scene after dynamic layout, wherein the four visual windows are the linkage windows obtained in the step 2.12;
when the maximum value of the frame range after dynamic layout is obtained according to the holographic projection imaging principle, the bottom edge length is as follows:
L＝w+2h (4)
h/w=n/m, then there is
Wherein w is the width of the visual window, and h is the height of the visual window;
after dynamic layout, the front view positions of the visual window drawing are as follows:
the rear view positions are:
the left view position is:
the right view position is:
step 3, optimizing the bridge construction holographic scene obtained in the step 2 during interaction, and drawing the optimized bridge construction holographic scene based on the digital twin bridge construction scene data to obtain a drawn bridge construction holographic scene;
the specific steps of the step 3 are as follows:
step 3.1, optimizing a bridge construction holographic scene during interaction;
step 3.2, rendering and drawing the bridge construction holographic scene in real time based on the digital twin bridge construction scene data loaded in the digital twin platform by the optimized bridge construction holographic scene, and obtaining a drawn bridge construction holographic scene;
The specific steps of the step 3.1 are as follows:
step 3.11, obtaining a fuzzy range of an object in each visual window during interaction, namely a fuzzy region, wherein the fuzzy region comprises a fuzzy region generated by linear motion fuzzy and rotary motion fuzzy, and the fuzzy degree is obtained by calculating a point spread function of the linear motion fuzzy and the rotary motion fuzzy, and the interaction comprises movement, rotation and scaling;
step 3.12, simplifying the fuzzy area by adopting a simplifying means, namely reducing the data precision, obtaining a simplified bridge construction holographic scene, namely obtaining an optimized bridge construction holographic scene during interaction, wherein the simplifying means comprises network simplification or texture compression;
in the step 3.11:
the point spread function of the linear motion blur comprises two parameters of total displacement and motion direction, the blurred image g (x, y) is formed by the linear motion of the original image f (x, y) in the direction forming an alpha angle with the x axis, and then the value of any point of the blurred image is as follows:
where g (x, y) is the value of any point of the blurred image, x 0 (t) is the motion component of the holographic scene for bridge construction in the x direction at the moment t, y 0 (T) is the motion component of the holographic scene for bridge construction in the y direction at the moment T, and if the total displacement of the object is a, the total time is T m The rate of movement is Then there are:
the discretization of the equation 12 obtains a blurred region of linear motion blur, and the equation is:
wherein L' is the number of pixels of the bridge construction holographic scene moving, i.e. the fuzzy scale, i is the ith pixel, u= [ i cos alpha ], v= [ isinalpha ], and alpha represents the motion direction;
the calculation of the fuzzy region by convolution operation can be:
g(x,y)＝f(x,y).h(u,v)
wherein (u, v) is a point spread function:
the rotational motion blur is different from the linear motion blur, is a spatially variable motion blur, has different blur parameters on different blur paths, and has larger blur scale as the rotational center is far away; the degree of blurring of points at the same position from the rotation center is the same, i.e. the degree of blurring of images on the same ring is the same, while the rotation motion blurring is distributed along different rotation paths;
assuming that the rotation center is the origin (0, 0), the distance between any pixel point i (x, y) in the blurred image g (x, y) and the rotation center isLet the rotation time of the object be T s When the rotational angular velocity is ω, the relationship between the blurred image g (x, y) and the original image f (x, y) is:
represented in polar vertex form:
wherein r represents a radial coordinate, represents a distance from an origin to i (x, y), θ represents an angular coordinate, represents a positive x-axis at a start edge, and represents an included angle between rays passing through the origin and i (x, y) at an end point;
Let l=r, θ, s=rωt, r is denoted as subscript, h r As the point spread function, the point spread function at the point where any pixel point i (x, y) is r from the rotation center length is h r (i) Then:
wherein the method comprises the steps of
The discrete processing of equation 16 yields a blurred region of rotational motion blur, which can be:
wherein i=0, 1,2, N r -1，g r (i) And f r (i) Respectively a blurred pixel value and an original gray value of an ith pixel point on a blurred path, N r Represents the number of pixel points, and L r The pixel number is used for representing the fuzzy scale;
the point spread function in the form of a rotational motion blur matrix is derived based on equation 17 as:
2. the method according to claim 1, wherein the digital twin bridge construction scene data in step 1 includes digital elevation, thematic data, bridge BIM model of bridge entity, inclination data, monitoring data, management data and geographical information data, wherein the digital elevation includes topography, thematic data includes river, vegetation, road, ground and measurement data, the bridge BIM data includes building information model of bridge deck, pier, suspension rope and bridge span of the bridge, the inclination data includes topography, ground, river, tree and building digital surface model, the monitoring data includes bridge construction stage monitoring data, wind field monitoring data in the construction scene, bridge stress field monitoring data, the management data includes bridge component attribute and bridge construction progress, and the geographical information data includes image, topography, road, river and building.
3. A holographic scene dynamic construction system of adaptive screen size, comprising:
the acquisition module is used for: acquiring digital twin bridge construction scene data;
and a dynamic construction module: the method comprises the steps of importing digital twin bridge construction scene data to construct a bridge construction holographic scene, and then dynamically constructing the self-adaptive screen size holographic scene based on the bridge construction holographic scene to obtain the position of a visual window drawing view of the bridge construction holographic scene, so as to obtain the bridge construction holographic scene with the self-adaptive screen size;
and a drawing module: optimizing the bridge construction holographic scene obtained by the dynamic construction module during interaction, and drawing the optimized bridge construction holographic scene based on digital twin bridge construction scene data to obtain a drawn bridge construction holographic scene;
the dynamic construction module comprises the following specific implementation steps:
step 2.1, importing digital twin bridge construction scene data to construct a bridge construction holographic scene, arranging four virtual cameras for rendering and drawing the scene in real time in the bridge construction holographic scene based on the bridge construction holographic scene, and constructing a linkage window based on the four virtual cameras, namely, the four virtual cameras are always aligned to a unified area in the same action, wherein the bridge construction holographic scene is a virtual scene of bridge construction;
Step 2.2, performing self-adaptive screen size picture segmentation and dynamic layout based on a pepper's theory, a holographic projection imaging theory and a linkage window, and obtaining the position of a visual window drawing view of the bridge construction holographic scene after the dynamic layout, thereby obtaining the bridge construction holographic scene with the self-adaptive screen size;
the specific steps of the step 2.1 are as follows:
step 2.11, importing digital twin bridge construction scene data to construct a bridge construction holographic scene, arranging four virtual cameras for rendering and drawing the scene in real time in the bridge construction holographic scene based on the bridge construction holographic scene, taking the plane where the four virtual cameras are positioned as an XY axis, taking the direction vertical to the XY axis as a Z axis, taking the center of the bridge construction holographic scene as an origin, establishing a coordinate system, and calculating to obtain a transformation relation between the virtual cameras so as to enable the cameras in the bridge construction holographic scene to aim at the same object in the same posture, wherein the transformation relation between the virtual cameras comprises translation, scaling and rotation between every two virtual cameras, and the translation refers to displacement of the virtual cameras in the bridge construction holographic scene, and then the displacement of the other three virtual cameras with the same dimension is carried out;
Let the distance from each virtual camera to the origin be l 0 Moving the bridge construction holographic scene to a point (x 0 ,y 0 ,z 0 ) The rotation of the virtual camera in the Y-axis direction is transformed into:
in the Y-axis direction, the scaling of the virtual camera is:
wherein y 0 |≤l 0 ；
The rotation of the virtual camera in the X-axis direction is transformed as follows:
in the X-axis direction, the scaling of the virtual camera is:
wherein, |x 0 |≤l 0 ；
Wherein alpha is y Euler angle, beta, around y-axis for a virtual camera coordinate system z Is the rotation angle alpha of the coordinate system around the z axis after the virtual camera rotates z Euler angle, x, around z-axis for a virtual camera coordinate system 0 Building a distance, y, of a holographic scene moving in the x-axis direction for a bridge 0 Building a distance z by which a holographic scene moves in the y-axis direction for a bridge 0 Building a distance for the bridge, in which the holographic scene moves in the z-axis direction;
step 2.12, adjusting each virtual camera based on the transformation relation among the virtual cameras to obtain a linkage window, namely, uniformly linkage of the four virtual cameras;
the specific steps of the step 2.2 are as follows:
2.21, defining four vertex coordinates of the screen as a (0, 0), b (0, n), c (m, 0) and d ((m, n) respectively based on a holographic projection imaging principle, wherein m and n are resolutions of the screen, and determining a central o coordinate of the screen as (m/2, n/2), so that a built holographic picture is always at the center of the picture and accords with the imaging principle of holographic projection, and a square with a side length of n is built by taking a point o as the center, wherein four vertexes of the square are a '(m/2-n/2, 0), b' (m/2-n/2, n), c '(m/2+n/2, 0) and d' (m/2+n/2, n) respectively, and performing self-adaptive screen size picture segmentation based on the four vertexes of the square to obtain a holographic picture imaging area;
Step 2.22, dynamically laying out four visual windows dynamically generated by four virtual cameras based on the holographic picture imaging area, and obtaining the positions of visual window drawing views of the bridge construction holographic scene after dynamic layout, wherein the four visual windows are the linkage windows obtained in the step 2.12;
when the maximum value of the frame range after dynamic layout is obtained according to the holographic projection imaging principle, the bottom edge length is as follows:
L＝w+2h (4)
h/w=n/m, then there is
Wherein w is the width of the visual window, and h is the height of the visual window;
after dynamic layout, the front view positions of the visual window drawing are as follows:
the rear view positions are:
the left view position is:
the right view position is:
the specific implementation steps of the drawing module are as follows:
step 3.1, optimizing a bridge construction holographic scene during interaction;
step 3.2, rendering and drawing the bridge construction holographic scene in real time based on the digital twin bridge construction scene data loaded in the digital twin platform by the optimized bridge construction holographic scene, and obtaining a drawn bridge construction holographic scene;
the specific steps of the step 3.1 are as follows:
step 3.11, obtaining a fuzzy range of an object in each visual window during interaction, namely a fuzzy region, wherein the fuzzy region comprises a fuzzy region generated by linear motion fuzzy and rotary motion fuzzy, and the fuzzy degree is obtained by calculating a point spread function of the linear motion fuzzy and the rotary motion fuzzy, and the interaction comprises movement, rotation and scaling;
Step 3.12, simplifying the fuzzy area by adopting a simplifying means, namely reducing the data precision, obtaining a simplified bridge construction holographic scene, namely obtaining an optimized bridge construction holographic scene during interaction, wherein the simplifying means comprises network simplification or texture compression;
in the step 3.11:
the point spread function of the linear motion blur comprises two parameters of total displacement and motion direction, the blurred image g (x, y) is formed by the linear motion of the original image f (x, y) in the direction forming an alpha angle with the x axis, and then the value of any point of the blurred image is as follows:
where g (x, y) is the value of any point of the blurred image, x 0 (t) is the motion component of the holographic scene for bridge construction in the x direction at the moment t, y 0 (T) is the motion component of the holographic scene for bridge construction in the y direction at the moment T, and if the total displacement of the object is a, the total time is T m The rate of movement is Then there are:
the discretization of the equation 12 obtains a blurred region of linear motion blur, and the equation is:
wherein L' is the number of pixels of the bridge construction holographic scene moving, i.e. the fuzzy scale, i is the ith pixel, u= [ i cos alpha ], v= [ isinalpha ], and alpha represents the motion direction;
the calculation of the fuzzy region by convolution operation can be:
g(x,y)＝f(x,y).h(u,v)
Wherein (u, v) is a point spread function:
the rotational motion blur is different from the linear motion blur, is a spatially variable motion blur, has different blur parameters on different blur paths, and has larger blur scale as the rotational center is far away; the degree of blurring of points at the same position from the rotation center is the same, i.e. the degree of blurring of images on the same ring is the same, while the rotation motion blurring is distributed along different rotation paths;
assuming that the rotation center is the origin (0, 0), the distance between any pixel point i (x, y) in the blurred image g (x, y) and the rotation center isLet the rotation time of the object be T s When the rotational angular velocity is ω, the relationship between the blurred image g (x, y) and the original image f (x, y) is:
represented in polar vertex form:
wherein r represents a radial coordinate, represents a distance from an origin to i (x, y), θ represents an angular coordinate, represents a positive x-axis at a start edge, and represents an included angle between rays passing through the origin and i (x, y) at an end point;
let l=r, θ, s=rωt, r is denoted as subscript, h r As the point spread function, the point spread function at the point where any pixel point i (x, y) is r from the rotation center length is h r (i) Then:
wherein the method comprises the steps of
The discrete processing of equation 16 yields a blurred region of rotational motion blur, which can be:
Wherein i=0, 1,2, N r -1，g r (i) And f r (i) Respectively a blurred pixel value and an original gray value of an ith pixel point on a blurred path, N r Represents the number of pixel points, and L r The pixel number is used for representing the fuzzy scale;
the point spread function in the form of a rotational motion blur matrix is derived based on equation 17 as:
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