CN105700162A - Optical field scanning based full parallax 360-degree 3D display device and method - Google Patents

Abstract

The invention discloses a full-parallax 360° three-dimensional display device based on light field scanning, which includes a deflection-type directional scattering screen, a cylindrical lens array screen, a high-speed projector, a rotating device, and a rotating detection device. The present invention also discloses a full parallax 360° three-dimensional display method based on light field scanning, which realizes full parallax three-dimensional display by performing light field reconstruction processing and integration processing on viewing angle images corresponding to each viewpoint. The present invention realizes the free full parallax three-dimensional display experience in the display space by combining the scanning light field reconstruction and integrated imaging display scheme; wherein the scanning light field reconstruction solution and the integrated imaging technology based on the cylindrical lens array are respectively horizontal The light field and the vertical light field are reconstructed to achieve full parallax 3D display with correct viewpoints in different horizontal and vertical positions.

Description

Full parallax 360° three-dimensional display device and method based on light field scanning

technical field

The invention belongs to the technical field of three-dimensional display, and in particular relates to a full parallax 360° three-dimensional display device and method based on light field scanning.

Background technique

In recent years, with the rapid development of optoelectronic technology and computer rendering technology, 3D display technology is undergoing unprecedented development, and more and more attention has been paid to the research and application of naked-eye 3D display with large viewing angle or even 360°. Existing 3D display technologies include holographic 3D display technology, volumetric 3D display technology, integrated imaging 3D display technology, and light field 3D display technology.

Holographic three-dimensional display uses the method of interference recording and diffraction reproduction to record and reproduce all wavefront information such as the intensity, phase and wavelength of the target light, so theoretically there is no difference between viewing a real object and viewing its holographic image. However, limited by the resolution of the photosensitive film and the wavelength of the reproduced light, the clarity and color reproduction of the actual display scene are greatly reduced, and it is difficult to apply to dynamic display. Volumetric 3D display uses LED arrays or laser scanning to reconstruct the full-angle luminescent voxel point cloud, which is easy to integrate and realize large-scale 3D display, but the light direction cannot be controlled, resulting in the reconstructed 3D scene being transparent. It has no occlusion effect and no texture display. Integrated imaging 3D display is realized through the combination of liquid crystal panel and cylindrical grating (or cylindrical lens array), which guides light containing specific information into a specific observation area, generates images corresponding to each viewpoint, and realizes 3D display. However, the resolution of the liquid crystal panel and the refraction ability of the cylindrical grating limit the correct number of viewing angles and the viewing angle of the system. Light field 3D display uses projection technology and directional screens to control the information and exit direction of light to achieve light field reconstruction of target objects. Compared with holographic display, light field 3D display that relies on computer rendering technology can achieve high-resolution dynamic and 3D scenes with complex textures. The implementation methods of light field three-dimensional display include scanning type and splicing type. Scanning light field 3D display realizes 360-degree scanning and reconstruction of light field through high-speed projectors and deflecting directional scattering screens, and splicing light field 3D display realizes splicing and reconstruction of light field through projector array and directional scattering screen.

With the continuous improvement of the resolution and modulation performance of various display devices, the realization effect of integrated imaging 3D display and light field 3D display is becoming more and more realistic, but limited by the actual mechanism, in order to realize horizontal parallax and vertical parallax at the same time, The display system needs to use a large number of projectors and microlens arrays, or add a human eye tracking module, which will make the entire system bulky and difficult to maintain.

Contents of the invention

In order to overcome the deficiencies of the prior art, the present invention provides a full parallax 360° three-dimensional display device and method based on light field scanning. Based on light field scanning technology, by combining scanning light field reconstruction and integrated imaging display solutions, Realize the free full parallax 3D display experience in the display space. The horizontal parallax is realized by the scanning light field reconstruction solution, that is, the image sequence obtained according to the mapping algorithm is synchronously projected onto the rotating transmissive directional scattering screen. Thanks to the light modulation characteristics of the deflection directional scattering screen, the system passes The rotating scanning realizes the reconstruction of the light field in the horizontal direction, and the user can observe the scene of the corresponding viewing angle around the display system. However, due to the large scattering angle in the vertical direction of the screen, this type of scanning light field system cannot realize vertical parallax. By superimposing the cylindrical lens array on the deflecting directional scattering screen, the secondary modulation of the light in the vertical direction can be realized, so that the light field reconstruction in the vertical direction can be realized, and a three-dimensional display with full parallax can be realized.

Concrete technical scheme of the present invention is as follows:

A full-parallax 360° three-dimensional display device based on light field scanning includes a deflection-type directional scattering screen, a cylindrical lens array screen, a high-speed projector, a rotating device, and a rotating detection device.

Deflection type directional scattering screen: horizontally modulate the outgoing direction of the incident light;

Cylindrical lens array screen: vertically modulate the outgoing direction of the incident light;

High-speed projector: Obtain a two-dimensional image sequence according to the optical characteristics of the screen, and project it to the corresponding position of the screen, and realize three-dimensional image display with the rotation of the screen;

Rotation device: connected with the directional scattering screen, and drives the directional scattering screen to rotate;

Rotation detection device: detect the rotation speed signal and angular position of the rotation device and transmit it to the high-speed projector to realize the control of the projected image.

Preferably, the deflection-type directional scattering screen deflects the incident light to the position of the observer at a specific angle, and at the same time makes the passing light have a larger scattering angle in one dimension and a smaller scattering angle in the other dimension. In order to cooperate with the light field control characteristics of the cylindrical lens array screen, the directional scattering screen group needs to be transmissive and have low dispersion. Preferably, the deflecting directional scattering screen is a transmissive deflecting holographic microstructured scattering screen, that is, a diffusing screen with directional gain at an angle between 30° and 60° relative to the normal line of the screen.

Preferably, the cylindrical lens array screen can guide light into the three-dimensional display area to form a converging point. When it covers the directional scattering screen and ensures that each cylindrical unit is accurately aligned with the projected pixels, the original Quadratic modulation of a uniformly distributed vertical light field. The number of spatial viewpoints of the reconstructed 3D scene is determined by parameters such as high-speed projector refresh rate, projection image resolution, screen rotation speed, and cylindrical lens array spatial frequency.

Preferably, the high-speed projector is a color high-frame-rate projector, using a three-chip DLP high-speed spatial light modulator and corresponding three-color LED or laser lighting.

The present invention also provides a full parallax 360° three-dimensional display method based on light field scanning, the specific steps are as follows:

(1) The computer calculates the three-channel image sequence information for observers at different horizontal and vertical positions according to the parameters such as the three-dimensional model, the distance between the high-speed projector and the deflection-type directional scattering screen, and the color depth;

(2) According to the high-speed projection image resolution and the spatial frequency of the cylindrical lens array, the computer superimposes the image sequences corresponding to observers at different positions to construct a projected three-channel image sequence;

(3) The composite screen group is installed on the rotating device and rotated by it, the rotation detection device detects the rotational speed signal and the angular position of the rotating device and transmits it to the high-speed projector, and the high-speed projector synchronously updates the projected image according to the instruction;

(4) The outgoing direction of the incident light is modulated horizontally and vertically by the deflection-type directional scattering screen and the cylindrical lens array screen, so as to realize three-dimensional image display.

The present invention will combine the scanning light field reconstruction and the integrated imaging display scheme to simultaneously modulate the light horizontally and vertically, realize the free full parallax 3D display experience in the display space, and maintain a high display resolution of the 3D display (including horizontal and vertical angular resolution) and the number of reconstructed viewpoints.

Description of drawings

FIG. 1 is a schematic diagram of a full parallax 360° three-dimensional display device of the present invention.

Fig. 2 is a schematic diagram of horizontal parallax realized by scanning light field reconstruction in the present invention.

Fig. 3 is a principle diagram of realizing vertical parallax by integrated imaging technology in the present invention.

detailed description

The present invention will be described in detail below in conjunction with the accompanying drawings, but the present invention is not limited thereto.

As shown in Figure 1, the full-parallax 360° three-dimensional display device based on light field scanning includes: a high-speed projector 1, a deflection-type directional scattering screen 2, a cylindrical lens array screen 3, a rotating device 4, a rotating detection device 5 and an image control module6.

The core device of the high-speed projector 1 is a reflective digital micromirror device (DMD) with a high-speed modulation rate. Three DMDs can be used in combination with red, green and blue LED lighting to realize high-speed projection with color. The binary image of each channel displayed by the DMD is processed by the halftone algorithm to realize the display scene with gray levels.

As shown in Figure 2, the horizontal parallax is realized by means of scanning light field reconstruction: thanks to the optical properties of the deflection-type directional scattering screen 2 of the screen, the information projected onto the screen in time series will spread to 360° through the rotating device In the space, a scanning horizontal light field reconstruction is formed. Under the premise of accurate synchronization of rotation and projection, the system will have no crosstalk between viewpoints. Assume that at a certain moment, the directional scattering characteristics make the light passing through the screen point A propagate along the direction a, and enter the left eye of the observer; at another moment, the directional scattering characteristics make the light passing through the screen point B propagate along the b direction, and enter the observer's left eye. the patient's right eye. If the projected image can make the screen point A display the intensity information of the spatial point Q along the direction a, and the screen point B display the intensity information of the spatial point Q along the b direction, then the observer's eyes trace the two rays in reverse and end at the spatial convergence point Q, instead of point A and point B on the screen, this is the result of the stereoscopic perception of the brain. Complex 3D models can be regarded as a collection of point clouds. According to this idea, given the peripheral position of the observer's viewpoint, a sequence of projected images will be obtained. Since the screen has no modulation capability in the vertical direction, the system can only construct the horizontal light field of the Q point, but cannot construct its vertical light field. The number of horizontally reconstructed viewpoints is related to the number of images updated by the projector for one rotation of the screen.

As shown in Figure 3, the vertical parallax is realized by integrated imaging technology: the cylindrical lens array screen 3 has the ability to adjust in the vertical direction, and can disperse and image the pixels of the object plane integrated display into the free space, so the View images at different positions in the vertical direction are superimposed in the coverage area of each grating unit according to the integrated imaging algorithm, and the observer will observe parallax images without crosstalk in the vertical direction. The number of vertically reconstructed viewpoints is related to the period of the cylindrical lens array and the resolution of the projected image. If it is assumed that the period of the cylindrical lens array is Tmm and the resolution of the projected image is Pmm/pixel, then the number of vertically reconstructed viewpoints is T/P.

The rotating device 4 drives the transmissive composite screens 2 and 3 to rotate, and the high-speed projector 1 is placed under the composite screen, and the rotating device 4 cannot block the projected image of the projector, so a pulley transmission method or a hollow cylinder method can be used. Realize the design of the rotating device. In order to realize the precise cooperation between the projected image and the rotating screen, the design should avoid slipping and shifting due to poor cooperation when rotating.

The rotation detection device 5 detects the real-time rotation status of the system, can directly read the rotation device signal to obtain rotation status information, and can also detect the rotating screen in real time. The rotation detection device 5 is generally a control module based on a field programmable gate array or a control module based on a digital signal processor as a core, and is transmitted to the image control module after collecting and processing the rotational speed and angular position signals of the rotating device 4 6.

The image control module 6 pre-calculates the perspective images corresponding to each viewpoint according to the given 3D model and viewpoint position set (including the viewpoint distribution of the horizontal angle α distribution and the vertical angle β distribution), and generates a projection image set according to the reconstruction algorithm . According to the previous description, the projection images corresponding to the same horizontal angle α but different vertical angles β will be superimposed into a single integrated projection image according to the algorithm. Since the high-speed projector 1 displays three color images, it is necessary to separate the color channels of the projection image and Do halftoning. According to the angular position information fed back by the rotation detection device 5 , the image control module 6 transmits the integrated projection image corresponding to each horizontal angle α to the high-speed projector 1 to realize precise control.

The above descriptions are only examples of the preferred implementation of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention within.

Claims (6)

1. 360 ° of three-dimensional display apparatus of full parallax based on light field scanning, it is characterised in that include high-speed projector, deviation type directional scattering screen, cylindrical lens array screen and tumbler；

Described high-speed projector, for by sequential projection two dimensional image to described deviation type directional scattering screen and cylindrical lens array screen；

Described deviation type directional scattering screen, the exit direction for incident ray carries out level modulation；

Described cylindrical lens array screen, the exit direction for incident ray is vertically modulated；

Described tumbler, for driving described deviation type directional scattering screen and cylindrical lens array screen to rotate, shows realizing 3-D view。

2. complete 360 ° of three-dimensional display apparatus of parallax as claimed in claim 1, it is characterized in that, there is the rotation detecting device being connected with described tumbler, for detecting tach signal and the angle position of tumbler, and export the regulation and control realizing projection picture to high-speed projector。

3. complete 360 ° of three-dimensional display apparatus of parallax as claimed in claim 1, it is characterised in that described deviation type directional scattering screen is the scattering screen that screen normal has directive gain between 30 ° to 60 ° angles。

4. complete 360 ° of three-dimensional display apparatus of parallax as claimed in claim 3, it is characterised in that described deviation type directional scattering screen is transmission-type deviation type holographic microstructure diffuser screen。

5. complete 360 ° of three-dimensional display apparatus of parallax as claimed in claim 1, it is characterised in that described high-speed projector is colored high frame frequency scialyscope, use three-chip type DLP high speed spatial light modulator and corresponding three-color LED or laser lighting。

6. 360 ° of 3 D displaying methods of full parallax based on 360 ° of three-dimensional display apparatus of parallax complete described in any one of Claims 1 to 5, it is characterised in that include step:

1) parameters according to threedimensional model, high-speed projector and deviation type directional scattering screen, the observer for varying level Yu vertical position arranges triple channel image sequence information；

2) spatial frequency according to projection image resolution ratio and cylindrical lens array at a high speed, is overlapped the image sequence corresponding to diverse location observer processing, and builds projection triple channel image sequence；

3) being driven deviation type directional scattering screen and cylindrical lens array screen by tumbler, utilize the tach signal of motion detection device detection tumbler and angle position and be transferred to high-speed projector, high-speed projector updates projection picture according to command synchronization；

4) respectively the exit direction of incident ray is horizontally and vertically modulated by described deviation type directional scattering screen and cylindrical lens array screen, show realizing 3-D view。