CN114185169B

CN114185169B - Scattering screen parameter optimization method, scattering screen and readable storage medium

Info

Publication number: CN114185169B
Application number: CN202010861889.8A
Authority: CN
Inventors: 请求不公布姓名
Original assignee: Chengdu Idealsee Technology Co Ltd
Current assignee: Chengdu Idealsee Technology Co Ltd
Priority date: 2020-08-25
Filing date: 2020-08-25
Publication date: 2024-03-05
Anticipated expiration: 2040-08-25
Also published as: CN114185169A

Abstract

The invention discloses a scattering screen parameter optimization method, a scattering screen and a readable storage medium, wherein the method is applied to light field display, equipment for realizing the light field display comprises a projector array and the scattering screen, the scattering screen is divided into N areas, the N areas are set as non-uniform scattering angles, and N is a positive integer; the method comprises the following steps: constructing a cost function related to the similarity variable or the stripe interval variable; optimizing the cost function according to a preset optimization algorithm, and determining an extremum of the cost function; determining an optimized scattering angle according to the extremum of the cost function; and N scattering angles corresponding to the extreme value are the optimized scattering angles. The technical problem that the light field display effect is poor due to the fact that the slit or the overlapping exists when pictures received by human eyes cannot be spliced well after light emitted by the projector passes through the directional scattering screen in the prior art is solved.

Description

Scattering screen parameter optimization method, scattering screen and readable storage medium

Technical Field

The present invention relates to the field of light field display, and in particular, to a method for optimizing parameters of a diffuser, and a readable storage medium.

Background

Light field display refers to a display mode in which light rays emitted by an object are reconstructed through projectors, as shown in fig. 1A, each projector constructs light rays emitted by each point on the object in different directions, and if enough projectors project enough light rays, the light rays are equivalent to constructing light rays emitted by a plurality of points forming the surface of the object in different directions. Thus, when the human eyes receive the light rays emitted by the projector at different angles, the human eyes can feel that the object can be observed from different angles, and the light field display in the true sense is realized.

To realize the real light field display, on one hand, a large number of projectors are required for projection and a large amount of data processing are required, so that in the actual light field display, the field of view in the vertical direction is sacrificed, and only the rays emitted by an object in the horizontal direction are reconstructed. Therefore, light rays are scattered in a large angle in the vertical direction in the light field display, so that a complete picture can be observed by observers at different heights. On the other hand, since the projector has a certain physical size, the light rays reconstructed in the horizontal direction have a certain interval, that is, the observer can see discontinuous pictures, so that the light rays are scattered in the horizontal direction by a small angle in the light field display, and the observer can see continuous pictures. At this time, each light beam emitted from the projector is scattered vertically at a large angle and scattered horizontally at a small angle to form a vertical bar on the observation plane, as shown in fig. 1B. The viewer in one position will observe a number of vertical bars from different projectors, thus making up a complete picture, as shown in fig. 1C.

In the current light field display scheme, a projector array is used in combination with a directional scattering screen to realize light field display. As shown in fig. 1D, after the light projected by the projector passes through the diffusion screen, the direction of the light is not changed, but the light is scattered at a small angle in the horizontal direction (x direction) and is scattered at a large angle in the vertical direction (y direction). The directional diffusion screen used in the current scheme is characterized in that light rays are incident on the diffusion screen from any angle, the direction of emergent light is unchanged, and the diffusion angles are the same, so that the directional diffusion screen with uniform diffusion angle is used. For projectors at different positions, the widths of stripes seen by human eyes and the intervals between adjacent stripes seen by human eyes are different, as shown in fig. 1C, the projector pictures received by human eyes cannot be well spliced by using a directional scattering screen with uniform scattering angles, and slits or overlapping exist, so that the light field display effect is poor.

Disclosure of Invention

The invention aims to provide a scattering screen parameter optimization method, a scattering screen and a readable storage medium, which are used for solving the technical problems that in the prior art, after light emitted by a projector passes through a directional scattering screen, pictures received by human eyes cannot be spliced well, slits or overlapping exist, and the light field display effect is poor.

In order to achieve the above object, a first aspect of the embodiments of the present invention provides a method for optimizing parameters of a diffuser, which is applied to light field display, where an apparatus for implementing the light field display includes a projector array and a diffuser, where light rays emitted from the projector array enter a human eye after being scattered by the diffuser, the diffuser is divided into N regions, the N regions are set as non-uniform scattering angles, and N is a positive integer; the method comprises the following steps:

constructing a cost function related to the similarity variable or the stripe interval variable; the similarity variable is used for indicating the similarity between an actual projection picture and an ideal projection picture which can be received by human eyes at a target viewpoint; the fringe interval variable is used for indicating the sum of fringe intervals of adjacent projectors which can be received by human eyes at a target viewpoint; the similarity variable and the fringe spacing variable are both related to N scatter angles of the N regions;

optimizing the cost function according to a preset optimization algorithm, and determining an extremum of the cost function;

determining an optimized scattering angle according to the extremum of the cost function; and N scattering angles corresponding to the extreme value are the optimized scattering angles.

Optionally, the method for calculating the similarity between the actual projected picture and the ideal projected picture that can be received by human eyes at the target viewpoint includes:

calculating the similarity between the actual projection picture and the ideal projection picture according to a structural similarity algorithm SSIM; wherein the target viewpoint is the position of the human eye; the number of the target viewpoints is one or more; when the target viewpoints are multiple, taking the sum of the child valence functions corresponding to the multiple target viewpoints as the cost function; the actual projection picture is calculated according to the three-dimensional object image and a preset projector stripe calculation method; the ideal projection picture refers to a picture corresponding to the target viewpoint in the three-dimensional object image.

Optionally, the preset projector stripe calculating method includes:

calculating the spot position and the spot size of the pixel projected on the scattering screen aiming at each pixel emergent from the projector; calculating a light scattering angle of the light spot in a preset direction according to the size of the light spot and the scattering angle of the area where the position of the light spot is located, wherein the preset direction is a horizontal direction or a vertical direction; judging whether light scattered by the light spot of the pixel point through the scattering screen can enter human eyes at the target viewpoint or not according to the light scattering angle and the position of the target viewpoint;

calculating all pixel points emitted by each projector and capable of being received by human eyes at the target viewpoint;

according to the pixel points, projector stripes emitted by the projector and capable of being received by human eyes at the target viewpoint are obtained;

and calculating all projector fringes emitted by the projectors in the projector array and capable of being received by human eyes, and generating the actual projection picture according to all projector fringes.

Optionally, the method of calculating the sum of adjacent projector stripe intervals received at the target viewpoint comprises:

calculating all projector fringes emitted by projectors in the projector array and capable of being received by human eyes;

calculating the sum of intervals between adjacent projector stripes in all projector stripes as the sum of intervals of the projector stripes; wherein when two adjacent projector stripes overlap, the overlapping width is taken as the interval between the two adjacent projector stripes.

Optionally, the preset optimization algorithm is one of a genetic algorithm, a particle swarm algorithm or a steepest descent method.

Optionally, optimizing the cost function according to a preset optimization algorithm includes:

initializing a population, wherein the population comprises M individuals, and the information of each individual is used for indicating the respective scattering angles of the N areas, wherein M is a positive integer;

calculating a cost function for each of the individuals;

judging whether a preset condition for stopping optimization calculation is met;

if yes, determining extremum of cost functions of the M individuals;

and if not, iterating the M individuals according to the preset optimization algorithm.

Optionally, the condition for stopping the optimization calculation is at least one of the following:

optimizing the calculated times to reach the set times;

the average value of the cost functions of the M individuals meets a preset condition;

the cost function of at least one of the M individuals meets a preset condition.

Optionally, when the preset optimization algorithm is a genetic algorithm, iterating the M individuals according to the preset optimization algorithm includes:

calculating an adaptive value for each of the individuals; wherein the individual adaptive value refers to the value of the individual cost function;

reselecting M individuals from the population based on the adaptive value of each individual and a preset selection algorithm;

and performing cross mutation on the M newly selected individuals to generate a next generation population.

The second aspect of the embodiment of the present invention provides a diffusion screen, which is applied to a light field display device, where the light field display device further includes a projector array, light rays emitted from the projector array enter a human eye after being diffused by the diffusion screen, the diffusion screen includes N regions, the N regions are set as non-uniform diffusion angles, and N is a positive integer.

Optionally, the scattering screen is a micro lens array; or the diffuser screen comprises a horizontal lenticular lens array and a vertical lenticular lens array.

A third aspect of the embodiments of the present invention provides a computer-readable storage medium having stored thereon a computer program which, when executed by a processor, causes the processor to perform the method of the first aspect.

A fourth aspect of the present invention provides a light field display method, applied to a light field display device, where the light field display device includes a projector array and a scattering screen, and light rays emitted from the projector array enter a human eye after being scattered by the scattering screen, and the method includes:

emitting light rays corresponding to the image to be projected through the projector array;

when the light rays are incident to different areas of the scattering screen, the light rays are unevenly scattered through the different areas of the scattering screen; the diffusion screen is divided into N areas, the N areas have non-uniform diffusion angles, and N is a positive integer.

One or more technical solutions in the embodiments of the present invention at least have the following technical effects or advantages:

in the scheme of the embodiment of the invention, the scattering angles of N areas are set as non-uniform scattering angles, the cost function related to similarity variables or fringe interval variables is constructed, the cost function is optimized according to a preset optimization algorithm, the extremum of the cost function is determined, then N scattering angles corresponding to the extremum are determined as the optimized scattering angles, as the similarity variables or fringe interval variables can reflect the quality of splicing, the higher the similarity is, the smaller the fringe interval is, the better the splicing quality is, therefore, by optimizing the cost function, a group of scattering angle parameters (namely N scattering angles) which can enable the fringes emitted by each projector to be approximately perfectly spliced at the target viewpoint are found, and then the group of scattering angle parameters are set as the scattering angles of each area of the scattering screen, so that the technical problems in the prior art are solved that after the light emitted by the projector passes through the directional scattering screen, the pictures at the target viewpoint cannot be spliced well, slits or overlapping exist, and the splicing quality of the light field display effect is poor are realized.

Drawings

For a clearer description of embodiments of the invention or of solutions in the prior art, the drawings that are necessary for the description of the embodiments or of the prior art will be briefly described, it being evident that the drawings in the following description are only some embodiments of the invention, and that other drawings can be obtained, without inventive faculty, by a person skilled in the art from these drawings:

FIG. 1A is a schematic diagram of a light field display;

FIGS. 1B-1C are schematic diagrams of projector fringes;

FIG. 1D is a schematic view of the light path of light through a diffuser;

FIG. 2 is a schematic flow chart of a scattering angle optimization method according to an embodiment of the present invention;

fig. 3 is a schematic diagram of light paths of a plurality of pixel points emitted by a projector according to an embodiment of the present invention;

fig. 4 is a flowchart of an iteration method based on a preset optimization algorithm according to an embodiment of the present invention;

FIG. 5 is a schematic flow chart of a population iteration method based on a genetic algorithm according to an embodiment of the present invention;

FIG. 6 is a graph showing the comparison of the display effects of the light fields before and after the scattering angle optimization method according to the embodiment of the present invention;

fig. 7 is a schematic structural diagram of a microlens array according to an embodiment of the present invention;

fig. 8 is a schematic structural diagram of a lenticular lens array according to an embodiment of the present invention.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. 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.

In the embodiment of the invention, the action principle of the scattering screen in the space light field is firstly described.

As shown in fig. 1C and 1D, the spatial light field device includes a projector array and a diffuser screen disposed in a light direction of the projector array, and a user is typically positioned on the other side of the diffuser screen for viewing, as shown by the human eye position in fig. 1D. The scattering screen can be a plane scattering screen or a curved scattering screen. After passing through the scattering screen, the light rays projected by the projector are scattered at a small angle along the x direction and at a large angle along the y direction. Thus, each light ray exiting the projector will be scattered into a vertical bar after passing through the projector, as shown in fig. 1C. When the human eye is located at a certain position, for each projector, a light beam within a certain angle range enters the human eye after being scattered by the scattering screen. The effect that produces is that the human eye sees the vertical bar that has certain width on the diffuser screen, and a complete picture is pieced together through these vertical bars.

In embodiments of the present invention, the projector in the projector array may be an LCD (Liquid Crystal Display ) projector, a DLP (Digital Light Procession, digital light processing) projector, an LCOS (Liquid Crystal on Silicon, liquid crystal on silicon/liquid crystal on silicon) projector, or a fiber scanning projector.

In the embodiment of the invention, the directional scattering screen with non-uniform scattering is designed by an optimization algorithm and is used for seamless splicing of the light field display pictures. The diffuser screen includes N regions arranged at non-uniform scattering angles. Wherein, N is a positive integer, the value of N can be set according to actual needs, and when the scattering angle is optimized, the scattering angle in the horizontal direction or the vertical direction can be optimized, and the scattering angles in the horizontal direction and the vertical direction can be simultaneously optimized. The regions may be divided at equal intervals or non-equal intervals. For example: when the scattering angle in the horizontal direction is optimized, the scattering screen may be divided into N regions in the horizontal direction, which is not limited in the present invention.

In the embodiment of the present invention, the scattering angle to be optimized is described as an example of the scattering angle in the horizontal direction. Fig. 2 is a schematic flow chart of a scattering angle optimization method according to an embodiment of the present invention, where the method includes the following steps.

In step 201, a cost function is constructed for the similarity variable or stripe interval variable.

Wherein the similarity variable is used for indicating the similarity between an actual projection picture and an ideal projection picture received at the target viewpoint; the fringe interval variable is used to indicate the sum of adjacent projector fringe intervals received at the target viewpoint.

In the embodiment of the invention, the similarity variable and the fringe interval variable are both related to the scattering angles of N areas, the scattering angles of the N areas are changed, the similarity and the fringe interval are correspondingly changed, the similarity variable or the fringe interval variable can reflect the quality of splicing, and the higher the similarity is, the smaller the fringe interval is, the better the splicing quality is, so that the extremum of the cost function can be obtained by optimizing the cost function, and then the optimal set of scattering angles is selected.

Step 202, optimizing the cost function according to a preset optimization algorithm, and determining an extremum of the cost function; the preset optimization algorithm may be a genetic algorithm, a particle swarm algorithm, a steepest descent method, or the like.

In the embodiment of the invention, the extremum of the cost function can be the maximum value or the minimum value of the cost function, for example, the cost function can be S if the similarity is S, and the cost function is optimized to the maximum value when the cost function is optimized, so that the similarity is the highest; when the cost function is (1-S), the cost function can be optimized to the minimum value, so that the similarity subtracted by 1 is minimum; also for example: the cost function may be a sum of stripe intervals, and when the cost function is optimized, a minimum value of the cost function value may be optimized so that the stripe intervals are minimized.

Step 203, determining an optimized scattering angle according to the extremum of the cost function; and N scattering angles corresponding to the extreme value are the optimized scattering angles.

Therefore, in the above scheme, by optimizing the cost function, a set of scattering angle parameters which can enable the stripes emitted by each projector to be approximately perfectly spliced at the target viewpoint are found, and then the set of scattering angle parameters are set to be the scattering angles of each region of the scattering screen, so that the technical effects that in the prior art, after light emitted by the projector passes through the directional scattering screen, pictures received by human eyes cannot be well spliced, slits or overlapping exist, the technical problem that the light field display effect is poor is solved, and the technical effect of improving the splicing quality of each projector at the target viewpoint is realized.

Next, how to construct the cost function will be explained.

In one possible implementation, the cost function is a function of the similarity variable at the target viewpoint. Therefore, the cost function can be constructed by calculating the similarity between the received actual projection picture and the ideal three-dimensional object picture (i.e., the picture corresponding to the target viewpoint in the three-dimensional object picture) at the target viewpoint. In the embodiment of the invention, the cost function can be set as S or (1-S), and the similarity S ranges from 0 to 1.

In the embodiment of the invention, a structural similarity algorithm (SSIM, structural SIMilarity) can be adopted to calculate the picture similarity. As shown in fig. 3, the target viewpoint means the position E where the observer/human eye is located, eu and Ep are edges of the pupil of the human eye. The number of target viewpoints may be one or more; when a plurality of viewpoints are set, the similarity S between the actual projection picture that can be seen by the viewpoints and the ideal three-dimensional object picture can be calculated, and the sum of the child cost functions corresponding to the plurality of viewpoints is taken as the total cost function. In the embodiment of the invention, the number of the target viewpoints can be set according to the factors such as the application scene, the size of the space environment and the like, and the values of the target viewpoints can be 1-10, 1-20 or more, so that the invention is not limited to the above.

In the embodiment of the invention, the actual projection picture can be calculated according to the three-dimensional object image and a preset projector stripe calculation method. As shown in fig. 3, S1 to Sn are pixel positions (spot positions) projected by a projector on a diffusion screen. The preset fringe calculation method comprises the following steps.

And step 1, calculating the spot position and the spot size of a single pixel point emitted by the projector on the scattering screen. The spot size is ds=dp×tan (fp/L), where Dp is the size of a single pixel point from which the projector emits, fp is the focal length of the projection lens of the projector, and L is the distance from the projector to the center of the diffuser (if the projector is arranged along an arc, the center of the circle is at the center of the diffuser, L is the radius of the arc at which the projector array is located). According to the projector position, a ray equation of the central ray PP1 of the pixel point can be obtained, if S1 is the intersection point of the ray PP1 and the scattering screen, the intersection point position S1 is the position of the light spot, wherein the projector position refers to the position of the projector in a coordinate system established by taking the center of the scattering screen as the origin.

And 2, dividing the common display area of the scattering screen. Taking the horizontal direction (X direction) as an example, the common display area is equally divided into Ms points, and the adjacent point distance is made equal to or slightly smaller than Ds. Assuming that the common display area is Ls, the point at the-Ls/2 position is the first point S1 (S1 is the intersection point of the light PP1 and the diffuser), and the-Ls/2+ls/Ms is the coordinates of the second point, so that the coordinates of each point after the common display area is divided can be calculated in sequence.

In step 3, S1 is the first point, sn is the nth point, and the range (Siu, sid) of the spot size of each projector pixel on the scattering screen is (-0.5×ds+x (i), 0.5×ds+x (i)), where x (i) is the position of the ith dividing point, and i is a positive integer less than or equal to n.

And step 4, calculating the light spot scattering angle. Considering only the X direction, assuming that the projector position is (xp, zp), the diffuser is located at the z=0 plane, the projector projects the same onto the display area, the chief ray angle of the X (i) th point is θi=arctan ((X (i) -xp)/(0-zp)), after the light rays corresponding to the two edges of the X (i) th light spot exit the diffuser, the light ray scattering angles are θi1=θi- θp 0.5+θs, θi2=θi+θp 0.5+θs, where the beam divergence angle is θp, that is, the divergence angle of the light rays projected by the projector into a single pixel, and the diffuser scattering angle is θs.

In step 5, please continue to refer to fig. 5, wherein E is the observer pupil position, the observer pupil position is calculated, only the horizontal direction is considered, the observer eye position is (xe, ze), wherein the observer eye position is the position of the observer eye in the coordinate system established by taking the center of the diffuser as the origin, and the pupil size is De, and the pupil range is represented by the pupil edge horizontal position (Eu, ep) as (xe-0.5×de, xe+0.5×de).

Step 6, calculating whether the light spot can enter human eyes, as shown in fig. 5, when the ith light spot of the common display area propagates to the distance ze of the human eyes, the light spot range (Piu, pid) is (-0.5×ds+x (i) +ze tan (θi1), 0.5×ds+x (i) +ze tan (θi2), and if the range overlaps with the pupil range of the human eyes, the human eyes can see the light spot.

According to the method from step 1 to step 6, the pixels which can enter human eyes in all the pixel points (including S1 to Sn) projected by the projector can be calculated, so that the projector stripes which can be observed by human eyes and are emitted by the projector can be obtained.

Similarly, for other projectors in the projector array, the same method can be adopted to calculate and obtain the stripes which can be observed by the position of the human eyes, and then according to the viewpoint position of the observer, the image formed by all the stripes which can be seen by the observer, namely the actual projection picture, can be obtained. And for observers at different positions, corresponding projector stripes and actual projection pictures can be calculated by adopting the same method.

In the embodiment of the invention, if the three-dimensional object picture under ideal conditions is a real-scene three-dimensional object, the picture can be obtained by photographing with a camera at the observer position; in the case of a virtual three-dimensional object, the resulting picture can be photographed in software with a virtual camera.

In another possible implementation, the cost function is a function of the fringe spacing variable at the target viewpoint, please continue to refer to fig. 3, and the foregoing embodiment illustrates that all pixels that can enter the human eye in the pixel points projected by a single projector can be calculated, so that the projector fringes that can be observed by the human eye can be obtained. Further, the interval between adjacent projector stripes can be calculated by the positions of the projector stripes, and when the stripes overlap, the width of the overlapping stripes is taken as the stripe interval, and the interval is always a non-negative number. The cost function is the sum of adjacent projector spacings at the target viewpoint. Also, when a plurality of viewpoints are set, the intervals may be superimposed as a cost function for different viewpoints.

Next, taking a preset optimization algorithm as an example of a genetic algorithm, a scatter angle optimization method in the embodiment of the present invention will be described. As shown in fig. 4, the following steps are included.

Step 401, initializing a population. The population includes M individuals, and the information of each individual is used to indicate the respective scattering angles of the N regions, that is, one individual corresponds to one possible scattering angle optimization parameter, and M, N is a positive integer.

In the embodiment of the present invention, the number of scattering angles included in each individual is the same as the number of different scattering angle areas of the scattering screen, for example: dividing the scattering screen into 16 areas, and determining scattering angles of the 16 areas, wherein each individual comprises scattering angle information of the 16 areas; also for example: dividing the scattering screen into 24 areas, determining the scattering angles of the 24 areas is needed, and then each individual body comprises the scattering angle information of the 24 areas. The number of individuals in the population may be set as desired to strike a balance between ensuring accuracy and reducing the amount of computation. In the embodiment of the invention, 150 individuals in a population are taken as an example for illustration.

In the genetic algorithm, the scattering angle information in the individual needs to be encoded, and a binary encoding method, a floating point encoding method or a symbol encoding method can be adopted in the encoding process. In the embodiment of the present invention, binary encoding is taken as an example for explanation.

Assuming that the optimal range of the scattering angle of the scattering screen is 0.6 ° to 1.5 °, if each angle has an 8-bit coding length, the optimal angle range of 0.6 ° to 1.5 ° can be divided into 256 parts, and the coding length corresponding to the scattering angle of 16 regions is 128 (8x16=128). The coding of each individual is randomly initialized, namely, each individual is randomly initialized to 128-bit binary numbers, the number of the individuals in the population is 150, 150 128-bit binary numbers are generated after random initialization, namely, 150 individuals are generated, and the chromosome length of each individual is 128 bits.

Step 402, calculating a cost function for each of the individuals.

In the embodiment of the invention, the cost function is a function related to a similarity variable or a stripe interval variable. And calculating a cost function corresponding to each individual according to the scattering angle information of the individual.

Step 403, determining whether a preset condition for stopping iterative computation is satisfied.

In the embodiment of the present invention, the condition for stopping iterative computation is at least one of the following: optimizing the calculated times to reach the set times; or the average value of the cost functions of the M individuals meets a preset condition; or the cost function of at least one of the M individuals meets the preset condition. If yes, go to step 404, if not, go to step 405.

The preset conditions can be set according to the result of optimization. For example, assuming that the cost function is a similarity S, when the cost function is optimized, the cost function needs to be optimized to a maximum value, and the preset condition may be set such that an average value of the cost functions of the M individuals is greater than or equal to a preset threshold value; for another example, assuming that the cost function is (1-S), the cost function needs to be optimized to a minimum value, the preset condition may be set such that an average value of the cost functions of the M individuals is less than or equal to a preset threshold value.

Step 404, determining extremum of cost functions of the M individuals, and determining an optimized scattering angle according to the extremum of the cost functions. And N scattering angles in the individual corresponding to the extremum are the optimized scattering angles.

And step 405, iterating the M individuals according to a preset optimization algorithm to generate a next generation population. And then returns to continue with step 402.

Next, iterations of the population will be described, still taking genetic algorithms as examples. The iteration of the M individuals according to the genetic algorithm includes the following steps, as shown in fig. 5.

Step 501, calculating an adaptive value of each individual in a population; in performing the scatter angle optimization, the cost function value of each individual can be calculated as the individual's adaptive value by referring to the similarity variable or the fringe interval variable.

Then, executing step 502, and performing individual selection copying according to the self-adaptive value of each individual and a preset selection algorithm; in embodiments of the invention, individuals may be selected using roulette selection (Roulette Wheel Selection), each individual being selected with a retention probability ofWherein f _i An adaptive value for each individual. Then, a population of the same number of individuals is generated according to the selection method. In other embodiments, the preset selection algorithm may also employ random contention selection (Stochastic Tournament), optimal reservation selection, expected value selection (Excepted Value Selection), and the like, which is not limited by the present invention.

And 503, performing cross mutation on the M newly selected individuals to generate a next generation population. The chromosomes of each individual have been described in the foregoing examples. When cross mutation is carried out, two individuals exchange binary chromosomes with random lengths at corresponding positions according to a certain probability, namely, chromosome cross is realized; and turning over the chromosome of the individual with a certain probability, namely changing 0 into 1 and 1 into 0, namely realizing chromosome variation.

FIG. 6 is a graph showing the comparison of the display effects of the light fields before and after the scattering angle optimization method according to the embodiment of the present invention; the left side is a three-dimensional model to be displayed, and the middle is an image seen by an observer when the scattering screen has a uniform scattering angle. As shown on the right, an image is seen by the observer at the resulting non-uniform scatter angle using the optimization procedure described above. As can be seen from fig. 6, when using a uniform scattering angle scattering screen, the images seen by the observer may have gaps or overlap, while using an optimized non-uniform scattering angle scattering screen, an approximately perfect stitching of the images may be achieved. In the process of optimization, assuming that the horizontal size of a picture projected by a projector is 200mm, and a scattering screen is divided into 11 areas in the horizontal direction, the scattering angles corresponding to the 11 areas at different positions after optimization are shown in table 1.

TABLE 1

Based on the same inventive concept, the embodiment of the invention also provides a scattering screen, which is applied to the light field display device, the light field display device further comprises a projector array, light rays emitted by the projector array enter human eyes after being scattered by the scattering screen, the scattering screen comprises N areas, and the scattering angles of the N areas are set according to the scattering screen parameter optimization method in the embodiment. The various modifications and specific examples of the method for optimizing the parameters of the diffuser in the embodiments of fig. 2 to 6 are equally applicable to the diffuser of this embodiment, and those skilled in the art will be aware of the implementation method of the diffuser in this embodiment through the foregoing detailed description of the method for optimizing the parameters of the diffuser, so they will not be described in detail herein for brevity of description.

In the embodiment of the invention, two possible forms of the diffuser are described. In light field displays, the diffuser used is required to have small angular scattering in the horizontal direction and large angular scattering in the vertical direction. In practical application, the function can be realized by one scattering screen or two scattering screens.

As shown in fig. 7, the diffusion screen is a microlens structure. Each microlens on the diffuser screen diffuses light from one pixel point emitted from the projector.

As shown in fig. 8, the diffusion screen is a diffusion screen composed of two cylindrical lens arrays, the left lens realizes large-angle vertical diffusion, and the right lens realizes small-angle horizontal diffusion. The scattering angle of the lens unit is calculated by the following formula:where f is the focal length of the lens and D is the cylinder diameter.

From the scattering angles and the positions of the lens units in table 1, a corresponding small-angle directional scattering screen can be designed to realize small-angle scattering in the horizontal direction. For vertical scattering at a large angle, in order to ensure that an observer can see a complete picture when squatting down or standing up, a fixed angle with a larger vertical scattering angle is generally taken, for example, the vertical scattering angle can be set to 60 degrees, and the corresponding structural parameters can be obtained according to the above formula.

The embodiment of the present invention also provides a computer-readable storage medium having a computer program stored thereon, which when executed by a processor causes the processor to perform the method of the above embodiment.

The embodiment of the invention also provides a light field display method, which is applied to light field display equipment, wherein the light field display equipment comprises a projector array and a scattering screen, and light rays emitted by the projector array enter human eyes after being scattered by the scattering screen, and the method comprises the following steps:

The various modifications and specific examples of the foregoing method for optimizing the parameters of the diffuser in the embodiments of fig. 2 to 8 are equally applicable to the method for displaying the light field in this embodiment, and those skilled in the art will be able to clearly know the implementation method of the method for displaying the light field in this embodiment through the foregoing detailed description of the method for optimizing the parameters of the diffuser, so that they will not be described in detail herein for brevity of description.

It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein. All of the features disclosed in this specification, or all of the steps in a method or process disclosed, may be combined in any combination, except for mutually exclusive features and/or steps.

Any feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. That is, each feature is one example only of a generic series of equivalent or similar features, unless expressly stated otherwise.

The invention is not limited to the specific embodiments described above. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification, as well as to any novel one, or any novel combination, of the steps of the method or process disclosed.

Claims

1. The utility model provides a scattering screen parameter optimization method, is applied to the light field and shows, realizes the equipment of light field demonstration includes projector array and scattering screen, the light that the projector array is launched enters the human eye after scattering by the scattering screen, characterized by that, the scattering screen is divided into N regional, N regional setting is inhomogeneous scattering angle, N is positive integer; the method comprises the following steps:

2. The method of claim 1, wherein the method of calculating a similarity between an actual projected picture and an ideal projected picture that can be received by a human eye at a target viewpoint comprises:

3. The method of claim 2, wherein the predetermined projector stripe calculation method comprises:

4. The method of claim 1, wherein the method of calculating the sum of adjacent projector stripe spacings receivable by a human eye at the target viewpoint comprises:

5. The method of any one of claims 1-4, wherein the pre-set optimization algorithm is one of a genetic algorithm, a particle swarm algorithm, or a steepest descent method.

6. The method of claim 5, wherein optimizing the cost function according to a preset optimization algorithm comprises:

calculating a cost function for each of the individuals;

if yes, determining extremum of cost functions of the M individuals;

7. The method of claim 6, wherein the condition to stop optimization calculations is at least one of:

optimizing the calculated times to reach the set times;

8. The method of claim 6, wherein iterating the M individuals according to a preset optimization algorithm when the preset optimization algorithm is a genetic algorithm comprises:

9. A diffuser screen for use in a light field display device, the light field display device further comprising an array of projectors, light rays exiting the array of projectors being scattered by the diffuser screen and entering an eye, the diffuser screen comprising N regions, the N regions being arranged as non-uniform scattering angles, the non-uniform scattering angles being optimized by the method of any one of claims 1-8, N being a positive integer.

10. The diffuser of claim 9 wherein said diffuser is a microlens array; or the diffuser screen comprises a horizontal lenticular lens array and a vertical lenticular lens array.

11. A computer readable storage medium, characterized in that the computer readable storage medium has stored thereon a computer program which, when executed by a processor, causes the processor to perform the method of any of claims 1-8.

12. The light field display method is applied to light field display equipment, the light field display equipment comprises a projector array and a scattering screen, and light rays emitted by the projector array enter human eyes after being scattered by the scattering screen, and is characterized by comprising the following steps:

when the light rays are incident to different areas of the scattering screen, the light rays are unevenly scattered through the different areas of the scattering screen; wherein the diffuser is divided into N regions having non-uniform scattering angles optimized by the method of any one of claims 1-8, N being a positive integer.