CN103792674B

CN103792674B - A kind of apparatus and method measured and correct virtual reality display distortion

Info

Publication number: CN103792674B
Application number: CN201410028245.5A
Authority: CN
Inventors: 郑臻荣; 李安; 夏新星; 吴懿思; 陈驰; 申俊飞; 张雅琴; 刘旭; 李海峰
Original assignee: Zhejiang University ZJU
Current assignee: Shenzhen Ansijiang Technology Co Ltd
Priority date: 2014-01-21
Filing date: 2014-01-21
Publication date: 2016-11-23
Anticipated expiration: 2034-01-21
Also published as: CN103792674A

Abstract

The invention discloses a method for measuring and correcting the distortion of a virtual reality display, comprising the following steps: a reticle images the reticle through an optical system to obtain a distorted grid image; According to the corresponding relationship, the distortion coefficient of each grid is calculated; draw the undistorted grid A on the distorted grid image, and according to the principle of reversible optical path, the object surface of the optical system has a distortion grid corresponding to grid A Grid A', and then use the distortion coefficient and the vertex coordinates of grid A to calculate the vertex coordinates of the distorted grid A', and generate a coordinate lookup table from the vertex coordinates of the distorted grid A'; use the coordinate lookup table to convert the image to be projected Converting to a pre-distorted image, inputting an image source, and imaging the pre-distorted image displayed by the image source to obtain an imaged image, comparing the imaged image with the pre-distorted image, adjusting the image source, and completing the correction of the image source. The invention also discloses a device for measuring and correcting the distortion of the virtual reality display.

Description

A device and method for measuring and correcting distortion of a virtual reality display

技术领域technical field

本发明涉及投影光学系统领域，具体涉及一种测量和校正虚拟显示显示器畸变的装置和方法。The invention relates to the field of projection optical systems, in particular to a device and method for measuring and correcting distortion of a virtual display display.

背景技术Background technique

虚拟现实显示器不同于一般的投影机，是一种可以将文字、图像等信息由光学系统直接投影在人眼成像的设备，投射的文字和图像调整在无穷远平面上，比如平视显示器（HUD）和头盔显示器（HMD），能够将外界的景象与显示器的资料融合在一起，使人们不需要低头就能够方便、舒适地看到他需要的重要资讯。A virtual reality display is different from a general projector. It is a device that can directly project information such as text and images from an optical system to the human eye for imaging. The projected text and images are adjusted on an infinite plane, such as a head-up display (HUD) And the helmet-mounted display (HMD), which can integrate the external scene with the data of the display, so that people can conveniently and comfortably see the important information he needs without looking down.

虚拟现实显示器最初应用于军用飞机，目前涉及的应用范围广泛，具备智能操作系统的虚拟现实显示器（HWD）开始商业化，比如谷歌眼镜；许多民用航空飞机上已经配备了平视显示器（HUD），同时，装配在汽车、火车或者地铁列车上可以更加方便地给驾驶员提供路况、导航等信息，避免注意力中断以及丧失对状态意识的掌握，提高驾驶的安全性。Virtual reality displays were originally used in military aircraft, and now they involve a wide range of applications. Virtual reality displays (HWD) with intelligent operating systems have begun to be commercialized, such as Google glasses; many civil aviation aircraft have been equipped with head-up displays (HUD), and at the same time , Assembled on cars, trains or subway trains can provide drivers with road conditions, navigation and other information more conveniently, avoid distraction and loss of state awareness, and improve driving safety.

但是，为了能使显示的信息不丢失，同时还要使观察者得到舒适的观感，在设计虚拟现实显示器的光学系统时必须满足高清晰度和大视场的要求，这会使得投影图像发生畸变，清晰度越高，视场越大，图像的畸变也越大，尤其是在边缘视场。一般的光学系统往往采用同轴的设计，此时图像的畸变是关于中心对称的，但是在一些特殊的装配环境下，虚拟现实显示器的光学系统必须采用离轴设计的形式，这会使得投影图像发生非常大的畸变，且畸变是不对称的。投影图像的畸变不仅会影响观察的舒适感，甚至会造成观察者对重要信息的误判，导致不必要的损失。因此，如何消除虚拟现实显示器投影图像的畸变是亟待解决的。However, in order to keep the displayed information from being lost and at the same time give the observer a comfortable look and feel, the optical system of the virtual reality display must meet the requirements of high definition and large field of view, which will cause distortion of the projected image , the higher the definition, the larger the field of view, and the greater the distortion of the image, especially in the peripheral field of view. The general optical system often adopts a coaxial design. At this time, the distortion of the image is symmetrical about the center. However, in some special assembly environments, the optical system of the virtual reality display must adopt an off-axis design, which will make the projected image Very large distortion occurs, and the distortion is asymmetrical. The distortion of the projected image will not only affect the comfort of observation, but even cause the observer to misjudge important information, resulting in unnecessary loss. Therefore, how to eliminate the distortion of the projected image of the virtual reality display is to be solved urgently.

发明内容Contents of the invention

本发明提供了一种测量和校正虚拟现实显示器畸变的方法和装置，在虚拟现实显示器像源上对图像做预先的畸变处理，来抵消光学系统所带来的畸变，达到校正投影图像畸变的目的。The invention provides a method and device for measuring and correcting the distortion of a virtual reality display, which performs pre-distortion processing on the image source of the virtual reality display to offset the distortion caused by the optical system and achieve the purpose of correcting the distortion of the projected image .

一种测量和校正虚拟现实显示器畸变的方法，包括以下步骤：A method of measuring and correcting distortion of a virtual reality display, comprising the steps of:

1）设定带有网格的分划板，将该分划板置于光学系统的物面，并经过光学系统对分划板成像得到畸变网格像，所述畸变网格像上具有畸变网格；1) Set a reticle with a grid, place the reticle on the object plane of the optical system, and image the reticle through the optical system to obtain a distorted grid image, which has distortion grid;

2）根据网格顶点坐标与畸变网格顶点坐标之间的对应关系，计算得到每个网格的畸变系数；2) Calculate the distortion coefficient of each grid according to the correspondence between the grid vertex coordinates and the distortion grid vertex coordinates;

3）在所述畸变网格像上划出无畸变的网格A，根据光路可逆原理，光学系统的物面上具有与网格A相对应的畸变网格A′，然后利用畸变系数与网格A的顶点坐标，计算出畸变网格A′的顶点坐标，并将畸变网格A′的顶点坐标生成坐标查找表；3) Draw an undistorted grid A on the distorted grid image. According to the reversible principle of the optical path, the object plane of the optical system has a distorted grid A′ corresponding to the grid A, and then use the distortion coefficient and the grid Calculate the vertex coordinates of the grid A', calculate the vertex coordinates of the distorted grid A', and generate a coordinate lookup table from the vertex coordinates of the distorted grid A';

4）利用坐标查找表将待投影图像转换为预畸变图像，并输入像源，并对像源所显示的预畸变图像成像，得到成像图像，对比成像图像与所述的预畸变图像，调整像源，完成对像源的校正；4) Use the coordinate lookup table to convert the image to be projected into a pre-distorted image, and input the image source, and image the pre-distorted image displayed by the image source to obtain an imaged image, compare the imaged image with the pre-distorted image, and adjust the image source, to complete the calibration of the image source;

5）将校正后的像源置于光学系统的物面，并向像源输入预畸变图像，经光学系统出射为无畸变的图像，完成对虚拟现实显示器的校正。5) Put the corrected image source on the object plane of the optical system, input the pre-distorted image to the image source, and output it as an undistorted image through the optical system, and complete the correction of the virtual reality display.

在步骤2）中，设网格的四个顶点坐标为(x₀,y₀)，(x₁,y₁)，(x₂,y₂)和(x₃,y₃)，畸变网格的四个顶点坐标为(u₀,v₀)，(u₁,v₁)，(u₂,v₂)和(u₃,v₃)，建立顶点坐标(x,y)与(u,v)之间的对应关系式：In step 2), set the coordinates of the four vertices of the grid as (x ₀ ,y ₀ ), (x ₁ ,y ₁ ), (x ₂ ,y ₂ ) and (x ₃ ,y ₃ ), and distort the grid The four vertex coordinates are (u ₀ , v ₀ ), (u ₁ , v ₁ ), (u ₂ , v ₂ ) and (u ₃ , v ₃ ), establish the vertex coordinates (x, y) and (u, v) Correspondence between:

$\{\begin{matrix} X x = = {f f}_{u u} ((U u,, V V)) \\ Y Y = = {f f}_{v v} ((U u,, V V)) \end{matrix}$

令 $A = [\begin{matrix} u_{0} & v_{0} & u_{0} v_{0} & 1 \\ u_{1} & v_{1} & u_{1} v_{1} & 1 \\ u_{2} & v_{2} & u_{2} v_{2} & 1 \\ u_{3} & v_{3} & u_{3} v_{3} & 1 \end{matrix}],$ 则 $\{\begin{matrix} A \times K_{X} = X \\ A \times K_{Y} = Y \end{matrix};$ make $A = [\begin{matrix} u_{0} & v_{0} & u_{0} v_{0} & 1 \\ u_{1} & v_{1} & u_{1} v_{1} & 1 \\ u_{2} & v_{2} & u_{2} v_{2} & 1 \\ u_{3} & v_{3} & u_{3} v_{3} & 1 \end{matrix}],$ but $\{\begin{matrix} A \times K_{x} = x \\ A \times K_{Y} = Y \end{matrix};$

其中，K_X和K_Y为畸变系数，分别表示为 $K_{X} = [\begin{matrix} k_{x 0} \\ k_{x 1} \\ k_{x 2} \\ k_{x 3} \end{matrix}], K_{Y} = [\begin{matrix} k_{y 0} \\ k_{y 1} \\ k_{y 2} \\ k_{y 3} \end{matrix}] .$ Among them, K _X and K _Y are distortion coefficients, expressed as $K_{x} = [\begin{matrix} k_{x 0} \\ k_{x 1} \\ k_{x 2} \\ k_{x 3} \end{matrix}], K_{Y} = [\begin{matrix} k_{the y 0} \\ k_{the y 1} \\ k_{the y 2} \\ k_{the y 3} \end{matrix}] .$

在步骤3）中，设无畸变的网格A的顶点坐标为(u'_n,v'_n)，根据光路的可逆性原理，得到：In step 3), set the vertex coordinates of the undistorted grid A as (u' _n , v' _n ), and according to the principle of reversibility of the optical path, we get:

$\{\begin{matrix} {x x}_{n no}^{' '} = = {u u}_{n no}^{' '} {k k}_{x x 00} + + {v v}_{n no}^{' '} {k k}_{x x 11} + + {u u}_{n no}^{' '} {v v}_{n no}^{' '} {k k}_{x x 22} + + 11 \cdot &Center Dot; {k k}_{x x 33} \\ {y the y}_{n no}^{' '} = = {u u}_{n no}^{' '} {k k}_{y the y 00} + + {v v}_{n no}^{' '} {k k}_{y the y 11} + + {u u}_{n no}^{' '} {v v}_{n no}^{' '} {k k}_{y the y 22} + + 11 \cdot &Center Dot; {k k}_{y the y 33} \end{matrix},, ((n no = = 0,1,2 0,1,2,, \cdot \cdot \cdot \cdot \cdot \cdot))$

其中，(x'_n,y'_n)畸变网格A′的顶点坐标。Among them, (x' _n ,y' _n ) is the vertex coordinates of the distortion mesh A'.

本发明还提供了一种测量和校正虚拟现实显示器畸变的装置，所述的虚拟现实显示器包括光学系统和像源，所述的装置包括光学系统畸变测量模块和预畸变图像生成模块；The present invention also provides a device for measuring and correcting distortion of a virtual reality display, the virtual reality display includes an optical system and an image source, and the device includes an optical system distortion measurement module and a pre-distorted image generation module;

所述的系统畸变测量模块用于测量光学系统的畸变系数；The system distortion measurement module is used to measure the distortion coefficient of the optical system;

所述的预畸变图像生成模块根据所述的畸变系数将待投影图像转换为预畸变图像；The pre-distorted image generation module converts the image to be projected into a pre-distorted image according to the distortion coefficient;

其中，所述的系统畸变测量模块包括：Wherein, the system distortion measurement module includes:

分划板，位于光学系统的物面位置，且带有无畸变网格；A reticle, located at the object plane of the optical system, with a distortion-free grid;

成像装置，用于采集无畸变网格经光学系统所成的像，得到畸变网格像；The imaging device is used to collect the image formed by the undistorted grid through the optical system to obtain the distorted grid image;

图像处理模块，根据畸变网格像中的畸变网格顶点坐标与无畸变网格顶点坐标之间的对应关系，得到畸变系数，并生成坐标查找表；The image processing module obtains the distortion coefficient and generates a coordinate lookup table according to the corresponding relationship between the vertex coordinates of the distorted grid and the vertex coordinates of the undistorted grid in the distorted grid image;

预畸变图像生成模块包括：The pre-distortion image generation module includes:

控制系统，根据所述的坐标查找表，将待投影图像转换为预畸变图像，The control system converts the image to be projected into a pre-distorted image according to the coordinate lookup table,

视频信号发生器，用于将所述的预畸变图像送入像源显示。The video signal generator is used to send the pre-distorted image to the image source for display.

优选的，成像装置包括相机镜头和CCD传感器。Preferably, the imaging device includes a camera lens and a CCD sensor.

在本发明的装置中，还包括位于所述光学系统物面位置，用于对所述分划板均匀照明的背光源。In the device of the present invention, it also includes a backlight located at the object plane of the optical system for uniformly illuminating the reticle.

所述的控制系统分别与背光源、图像处理模块和视频信号发生器连接，该控制系统还用于控制背光源。The control system is respectively connected with the backlight source, the image processing module and the video signal generator, and the control system is also used for controlling the backlight source.

本发明具有结构简单、快速校正和使用便捷的优点；根据系统要求可以实现不同精度的校正；另外，由于是通过对图像源做预先的畸变处理来抵消光学系统的畸变，属于电校正，所以光学系统在设计时可以尽量满足视场和清晰度等设计指标，而不需要考虑畸变的影响，这给设计者带来极大的方便，使其具有广泛的应用前景。The present invention has the advantages of simple structure, fast correction and convenient use; different precision corrections can be realized according to system requirements; in addition, since the distortion of the optical system is offset by pre-distorting the image source, it belongs to electrical correction, so optical When the system is designed, it can meet the design indicators such as field of view and definition as much as possible, without considering the influence of distortion, which brings great convenience to the designer and makes it have a wide application prospect.

附图说明Description of drawings

图1是本发明具体实施的系统流程图。Fig. 1 is a system flow chart of the embodiment of the present invention.

图2是本发明实施过程中畸变测量装置示意图。Fig. 2 is a schematic diagram of a distortion measurement device during the implementation of the present invention.

图3是本发明无畸变的网格分划板示意图Fig. 3 is the schematic diagram of grid reticle without distortion of the present invention

图4是本发明涉及畸变和预畸变算法的示意图。Fig. 4 is a schematic diagram of the present invention involving distortion and pre-distortion algorithms.

图5是本发明校正像源畸变的装置示意图。Fig. 5 is a schematic diagram of a device for correcting image source distortion according to the present invention.

图6是本发明校正后投影设备的示意图。FIG. 6 is a schematic diagram of the corrected projection device of the present invention.

图中：1为背光源、2为分划板、3为相机镜头、4为CCD传感器、5、6为数据处理模块、7为控制系统、8为像源、9为视频信号发生器、10为光学系统。In the figure: 1 is the backlight, 2 is the reticle, 3 is the camera lens, 4 is the CCD sensor, 5, 6 is the data processing module, 7 is the control system, 8 is the image source, 9 is the video signal generator, 10 for the optical system.

具体实施方式detailed description

为使本发明的结构、特征及优点更加清晰明了，现结合附图对整套装置和方法作进一步详细说明，但不应理解为对本发明保护范围的任务限定。In order to make the structure, features and advantages of the present invention clearer, the entire set of devices and methods will be further described in detail in conjunction with the accompanying drawings, but it should not be construed as limiting the scope of protection of the present invention.

如图1所示，系统流程分为三个部分，第一部分，是光学系统畸变测量和预畸变图像查找表生成；第二部分，是像源畸变校正；第三部分，是经过校正后的投影设备。As shown in Figure 1, the system process is divided into three parts. The first part is the optical system distortion measurement and the pre-distorted image lookup table generation; the second part is the image source distortion correction; the third part is the corrected projection equipment.

图2为图1系统流程中第一部分的装置示意图。将带有无畸变网格的分划板2置于光学系统10物面位置，分划板2的形状如图3所示，由若干个网格组成，系统要求的校正精度越高，相同面积上分划的网格数越多，反之亦然。FIG. 2 is a schematic diagram of the first part of the system flow in FIG. 1 . Place the reticle 2 with a distortion-free grid on the object plane of the optical system 10. The shape of the reticle 2 is shown in Figure 3, and it consists of several grids. The more grids are divided up, and vice versa.

分划板2经过光学系统10和相机镜头3在CCD传感器4上成像，所成像为带有畸变的网格图像，畸变的产生是由光学系统10造成的，相机镜头3采用超低畸变的工业相机镜头，所以相机镜头带来的畸变忽略不计。CCD传感器4将采集的图像送入图像处理模块5，经过图像的增强，提取畸变网格图像各个网格顶点坐标并保存。然后将得到的坐标值送入数据处理模块6，计算光学系统的畸变系数和预畸变图像的查找表。The reticle 2 is imaged on the CCD sensor 4 through the optical system 10 and the camera lens 3, and the image is a grid image with distortion. The distortion is caused by the optical system 10. The camera lens 3 adopts ultra-low distortion industrial The camera lens, so the distortion caused by the camera lens is negligible. The CCD sensor 4 sends the collected image to the image processing module 5, and after image enhancement, the coordinates of each grid vertex of the distorted grid image are extracted and saved. Then the obtained coordinate values are sent to the data processing module 6 to calculate the distortion coefficient of the optical system and the look-up table of the pre-distorted image.

结合图4来说明计算光学系统的畸变系数和预畸变图像的查找表的过程。取分划板区域中第i行，第j列的一个网格，如图4左侧的实线网格所示，该网格经过光学系统后在像面产生畸变，如图4右侧的实线网格所示，(x_n,y_n)和(u_n,v_n)分别为网格上四个顶点的坐标（n=0，1，2，3）。The process of calculating the distortion coefficient of the optical system and the look-up table of the pre-distorted image will be described with reference to FIG. 4 . Take a grid in the i-th row and j-th column in the reticle area, as shown in the solid-line grid on the left side of Figure 4. After the grid passes through the optical system, distortion occurs on the image plane, as shown in the right side of Figure 4 As shown in the grid with solid lines, (x _n , y _n ) and (u _n , v _n ) are the coordinates of four vertices on the grid (n=0, 1, 2, 3), respectively.

令 $X = [\begin{matrix} x_{0} \\ x_{1} \\ x_{2} \\ x_{3} \end{matrix}]$ $Y = \begin{matrix} \end{matrix} [\begin{matrix} y_{0} \\ y_{1} \\ y_{2} \\ y_{3} \end{matrix}]$ $U = [\begin{matrix} u_{0} \\ u_{1} \\ u_{2} \\ u_{3} \end{matrix}]$ $V = [\begin{matrix} v_{0} \\ v_{1} \\ v_{2} \\ v_{3} \end{matrix}]$ make $x = [\begin{matrix} x_{0} \\ x_{1} \\ x_{2} \\ x_{3} \end{matrix}]$ $Y = \begin{matrix} \end{matrix} [\begin{matrix} {the y}_{0} \\ {the y}_{1} \\ {the y}_{2} \\ {the y}_{3} \end{matrix}]$ $u = [\begin{matrix} u_{0} \\ u_{1} \\ u_{2} \\ u_{3} \end{matrix}]$ $V = [\begin{matrix} v_{0} \\ v_{1} \\ v_{2} \\ v_{3} \end{matrix}]$

(x₀,y₀)，(x₁,y₁)，(x₂,y₂)和(x₃,y₃)四点为顶点的四边形区域S与(u₀,v₀)，(u₁,v₁)，(u₂,v₂)和(u₃,v₃)四点为顶点的四边形区域S’间存在一个函数关系f满足：(x ₀ , y ₀ ), (x ₁ , y ₁ ), (x ₂ , y ₂ ) and (x ₃ , y ₃ ) quadrilateral area S with four vertices as vertices and (u ₀ , v ₀ ), (u ₁ , v ₁ ), (u ₂ , v ₂ ) and (u ₃ , v ₃ ) there is a functional relationship f between the quadrilateral area S' with four vertices as vertices:

这样我们认为四边形区域S’内的任意点经过函数f映射之后得到其在四边形区域S内对应点。In this way, we think that any point in the quadrilateral area S' is mapped by the function f to obtain its corresponding point in the quadrilateral area S.

下面我们选取比较简单的函数关系f进行详细说明。令Next, we select a relatively simple functional relationship f to describe in detail. make

$A A = = [\begin{matrix} {u u}_{00} & {v v}_{00} & {u u}_{00} {v v}_{00} & 11 \\ {u u}_{11} & {v v}_{11} & {u u}_{11} {v v}_{11} & 11 \\ {u u}_{22} & {v v}_{22} & {u u}_{22} {v v}_{22} & 11 \\ {u u}_{33} & {v v}_{33} & {u u}_{33} {v v}_{33} & 11 \end{matrix}]$

满足以下关系：Satisfy the following relationship:

$\{\begin{matrix} A A \times \times {K K}_{X x} = = X x \\ A A \times \times {K K}_{Y Y} = = Y Y \end{matrix}$

其中，K_X和K_Y为系统的畸变系数，分别表示为 $K_{X} = [\begin{matrix} k_{x 0} \\ k_{x 1} \\ k_{x 2} \\ k_{x 3} \end{matrix}], K_{Y} = [\begin{matrix} k_{y 0} \\ k_{y 1} \\ k_{y 2} \\ k_{y 3} \end{matrix}]$ Among them, K _X and K _Y are the distortion coefficients of the system, expressed as $K_{x} = [\begin{matrix} k_{x 0} \\ k_{x 1} \\ k_{x 2} \\ k_{x 3} \end{matrix}], K_{Y} = [\begin{matrix} k_{the y 0} \\ k_{the y 1} \\ k_{the y 2} \\ k_{the y 3} \end{matrix}]$

可以求出光学系统的畸变系数K_X和K_Y，用同样的方法分别算出所有网格对应的畸变系数，将得到的畸变系数返回给控制系统7并保存。The distortion coefficients K _X and K _Y of the optical system can be obtained, the corresponding distortion coefficients of all grids can be calculated in the same way, and the obtained distortion coefficients can be returned to the control system 7 and saved.

下一步，在畸变网格像的区域内划分若干无畸变的网格，网格的个数根据像源8的分辨率决定。假设其中一个无畸变网格位于某一畸变网格内，如图4右侧所示虚线，按照光路可逆的原理，该无畸变网格在光学系统的物面对应一个畸变网格，如图4左侧虚线网格所示，(x'_n,y'_n)和(u'_n,v'_n)分别为网格上四个顶点的坐标（n=0，1，2，3）。In the next step, a number of undistorted grids are divided in the region of the distorted grid image, and the number of grids is determined according to the resolution of the image source 8 . Assuming that one of the distortion-free grids is located in a certain distortion grid, as shown in the dotted line on the right side of Figure 4, according to the principle of reversible optical path, the distortion-free grid corresponds to a distortion grid on the object plane of the optical system, as shown in Fig. 4 As shown in the dotted grid on the left, (x' _n , y' _n ) and (u' _n , v' _n ) are the coordinates of four vertices on the grid (n=0, 1, 2, 3) respectively.

由前述的光学系统畸变参数K_X和K_Y以及无畸变网格的顶点坐(u'_n,v'_n)，根据光路的可逆性原理，可推出：From the aforementioned optical system distortion parameters K _X and K _Y and the vertex position (u' _n , v' _n ) of the undistorted grid, according to the principle of reversibility of the optical path, it can be deduced that:

$\{\begin{matrix} {x x}_{n no}^{' '} = = {u u}_{n no}^{' '} {k k}_{x x 00} + + {v v}_{n no}^{' '} {k k}_{x x 11} + + {u u}_{n no}^{' '} {v v}_{n no}^{' '} {k k}_{x x 22} + + 11 \cdot \cdot {k k}_{x x 33} \\ {y the y}_{n no}^{' '} = = {u u}_{n no}^{' '} {k k}_{y the y 00} + + {v v}_{n no}^{' '} {k k}_{y the y 11} + + {u u}_{n no}^{' '} {v v}_{n no}^{' '} {k k}_{y the y 22} + + 11 \cdot \cdot {k k}_{y the y 33} \end{matrix},, ((n no = = 0,1,2 0,1,2,, \cdot &Center Dot; \cdot \cdot \cdot \cdot))$

用同样的方法，把所有像面上无畸变的网格点在物面上的对应坐标全部算出，将得到的坐标值返回给控制系统7，整理后保存为坐标查找表。Using the same method, calculate all the corresponding coordinates of the grid points without distortion on the image surface on the object surface, return the obtained coordinate values to the control system 7, and save them as a coordinate lookup table after sorting.

图5为系统流程图1中校正像源畸变的装置示意图。控制系统7按坐标查找表将无畸变图像变换为预畸变图像，并输入像源8显示，经过预畸变的图像能够抵消光学系统的畸变，实现畸变校正。但是，由于像源控制电路的设计缺陷或者其他因素的干扰，会造成像源显示的图像和输入像源的图像不一致，即像源不能精确地显示原始的图像信息，因此要校正像源的畸变。FIG. 5 is a schematic diagram of a device for correcting image source distortion in the system flowchart 1. FIG. The control system 7 transforms the undistorted image into a pre-distorted image according to the coordinate look-up table, and inputs the image source 8 for display. The pre-distorted image can offset the distortion of the optical system and realize distortion correction. However, due to the design defect of the image source control circuit or the interference of other factors, the image displayed by the image source will be inconsistent with the image of the input image source, that is, the image source cannot accurately display the original image information, so the distortion of the image source must be corrected .

如图5所示，控制系统7按坐标查找表将无畸变的图像变换为预畸变图像，并输入像源8显示，像源显示的预畸变图像经过相机镜头3，在CCD传感器4上成像，CCD传感器将采集的图像送入图像处理模块5，对比输入像源的预畸变图像和像源上显示的预畸变图像，调整像源，直到像源显示的预畸变图像与输入像源的预畸变图像一致（两者相差在精度要求范围内），则完成像源畸变的校正。As shown in Figure 5, the control system 7 transforms the undistorted image into a pre-distorted image according to the coordinate lookup table, and inputs the image source 8 for display, and the pre-distorted image displayed by the image source passes through the camera lens 3 and forms an image on the CCD sensor 4, The image collected by the CCD sensor is sent to the image processing module 5, and the pre-distortion image of the input image source is compared with the pre-distortion image displayed on the image source, and the image source is adjusted until the pre-distortion image displayed by the image source and the pre-distortion image of the input image source If the images are consistent (the difference between the two is within the accuracy requirement range), then the correction of image source distortion is completed.

如图6所示为校正后的投影系统示意图，将校正后的像源8置于光学系统10的物面，控制系统7按坐标查找表将无畸变的图像变换为预畸变图像，并输入像源显示，由于图像是预先经过畸变的处理，所以预畸变图像在经过光学系统10成像时将光学系统带来了的畸变抵消，则最终所成像为无畸变的图像。Figure 6 is a schematic diagram of the corrected projection system. The corrected image source 8 is placed on the object plane of the optical system 10, and the control system 7 converts the undistorted image into a pre-distorted image according to the coordinate lookup table, and inputs the image The source shows that since the image is pre-distorted, the pre-distorted image cancels the distortion brought by the optical system when it is imaged by the optical system 10, and the final image is an undistorted image.

由上述原理可知，光学系统畸变的测量和像源畸变的校正只需在系统装配前校正一次，校正后，控制系统只需按预畸变图像查找表生成预畸变图像输入像源即可，则经光学系统投影后为无畸变的图像From the above principles, it can be seen that the measurement of the optical system distortion and the correction of the image source distortion only need to be calibrated once before the system is assembled. Distortion-free image after optical system projection

基于以上原理的投影系统畸变测量和校正装置，具有结构简单，快速校正，使用便捷等优点；根据系统要求可以实现不同精度的校正；另外，由于是通过对图像源做预先的畸变处理来抵消光学系统的畸变，属于电校正，所以光学系统在设计时可以尽量满足视场和清晰度等设计指标，而不需要考虑畸变的影响，这给设计者带来极大的方便，使其具有广泛的应用前景。The projection system distortion measurement and correction device based on the above principles has the advantages of simple structure, fast correction, and convenient use; different precision corrections can be achieved according to system requirements; The distortion of the system belongs to electrical correction, so the optical system can meet the design indicators such as field of view and definition as much as possible when designing the optical system, without considering the influence of distortion, which brings great convenience to the designer and makes it have a wide range of applications. Application prospects.

Claims

1. measure and the method for correction virtual reality display distortion for one kind, it is characterised in that include Following steps:

1) set the graticle with grid, this graticle is placed in the object plane of optical system, and warp Cross optical system and graticle imaging is obtained distortion grid picture, described distortion grid picture has distortion net Lattice；

2) according to the corresponding relation between mesh vertex coordinates and distortion grid apex coordinate, calculate Distortion factor to each grid；

If the four of grid apex coordinates are (x₀,y₀), (x₁,y₁), (x₂,y₂) and (x₃,y₃), distortion grid Four apex coordinates are (u₀,v₀), (u₁,v₁), (u₂,v₂) and (u₃,v₃), set up apex coordinate (x, y) with (u, v) Between corresponding relation formula:

\{\begin{matrix} X = f_{u} (U, V) \\ Y = f_{v} (U, V) \end{matrix}

OrderThen

Wherein, K_XAnd K_YFor distortion factor, it is expressed as

3) on described distortion grid picture, distortionless grid A is marked, according to light path principle of reversibility, light There is on the object plane of system the distortion grid A ' corresponding with grid A, then utilize distortion factor with The apex coordinate of grid A, calculates the apex coordinate of distortion grid A ', and by the top of distortion grid A ' Point coordinates generates coordinate look-up table；

If the apex coordinate of distortionless grid A is (u '_n,v′_n), according to the reversibility pricinple of light path, Arrive:

\{\begin{matrix} x_{n}^{'} = u_{n}^{'} k_{x 0} + v_{n}^{'} k_{x 1} + u_{n}^{'} v_{n}^{'} k_{x 2} + 1 \cdot k_{x 3} \\ y_{n}^{'} = u_{n}^{'} k_{y 0} + v_{n}^{'} k_{y 1} + u_{n}^{'} v_{n}^{'} k_{y 2} + 1 \cdot k_{y 3} \end{matrix}, (n = 0, 1, 2, ...)

Wherein, (x '_n,y′_n) apex coordinate of distortion grid A '；

4) utilize coordinate look-up table to be converted to predistortion image by image to be projected, and input image source, And to the predistortion image imaging shown by image source, obtaining image, contrast image is with described Predistortion image, adjust image source, complete the correction to image source；

5) image source after correction is placed in the object plane of optical system, and inputs predistortion image to image source, It is distortionless image through optical system exit, completes the correction to virtual reality display.

2. the side distorted based on the measurement described in claim 1 and correction virtual reality display The device of method, described virtual reality display includes optical system and image source, it is characterised in that institute The device stated includes optical system distortion measurement module and predistortion image generation module；

Described systematical distortion measurement module is for measuring the distortion factor of optical system；

Described predistortion image generation module according to described distortion factor by conversion image to be projected For predistortion image；

Described systematical distortion measurement module includes:

Graticle, is positioned at the object plane position of optical system, and with undistorted grid；

Imaging device, is used for gathering undistorted grid through optical system imaging, obtains distortion grid Picture；

Image processing module, according to the distortion grid apex coordinate in distortion grid picture and undistorted grid Corresponding relation between apex coordinate, obtains distortion factor, and generates coordinate look-up table；

Predistortion image generation module includes:

Control system, according to described coordinate look-up table, is converted to predistortion image by image to be projected,

Flying-spot video generator, shows for described predistortion image is sent into image source.

3. device as claimed in claim 2, it is characterised in that imaging device includes camera lens And ccd sensor.

4. device as claimed in claim 2, it is characterised in that also include being positioned at described optical system System object plane position, for the backlight to described graticle Uniform Illumination.

5. device as claimed in claim 4, it is characterised in that described control system respectively with Backlight, image processing module and flying-spot video generator connect, and this control system is additionally operable to control the back of the body Light source.