CN109632092A - A kind of luminance test system and method based on spatial light field - Google Patents

A kind of luminance test system and method based on spatial light field Download PDF

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CN109632092A
CN109632092A CN201811632061.4A CN201811632061A CN109632092A CN 109632092 A CN109632092 A CN 109632092A CN 201811632061 A CN201811632061 A CN 201811632061A CN 109632092 A CN109632092 A CN 109632092A
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张宇宁
李帅
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Southeast University
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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01JMEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J1/00Photometry, e.g. photographic exposure meter
    • G01J1/42Photometry, e.g. photographic exposure meter using electric radiation detectors
    • G01J1/4204Photometry, e.g. photographic exposure meter using electric radiation detectors with determination of ambient light

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Abstract

The invention discloses a kind of luminance test system and method based on spatial light field, CCD is demarcated in advance using the scaling method of traditional luminance meter, using this calculated relationship as the corresponding relationship of image grayscale and brightness, and then the image on required focal plane is obtained by light field refocusing algorithm, the Luminance Distribution in respective planes is converted thereof into again, by adjusting the image and its Luminance Distribution of the available different focal planes of relevant parameter of refocusing, it does not need to focus when measuring brightness, it operates very easy, and it can be quick, real-time capture spatial brightness information, match different measurement demands.

Description

一种基于空间光场的亮度测试系统及方法A brightness testing system and method based on spatial light field

技术领域technical field

本发明涉及一种基于空间光场的亮度测试系统及方法,属于显示器件测量领域。The invention relates to a brightness testing system and method based on a spatial light field, and belongs to the field of display device measurement.

背景技术Background technique

随着显示、照明等技术的高速发展,光环境的组成也越来越多样化,而对光环境的准确测量与评价也显得尤为重要。光环境的评价涉及多种指标,比如亮度、照度、光谱、频闪等等,其中,亮度作为光环境评价的一项重要指标,长期以来一直广受关注,如何便捷、准确地测量亮度,是一个非常关键的问题。With the rapid development of display, lighting and other technologies, the composition of the light environment is becoming more and more diverse, and the accurate measurement and evaluation of the light environment is also particularly important. The evaluation of light environment involves a variety of indicators, such as brightness, illuminance, spectrum, stroboscopic, etc. Among them, brightness, as an important indicator of light environment evaluation, has been widely concerned for a long time. How to measure brightness conveniently and accurately is a A very crucial question.

对于亮度测量的研究由来已久,取得了一些成果,目前市面上已有多种亮度计可供选择。比较常见的亮度计有遮光筒亮度计、瞄点式亮度计以及CCD成像亮度计等,其中遮光筒亮度计的特点是制造简单,使用方便,不足之处是它的测量准确度不高,探测器接收面很小,只有当圆筒小孔半径小于筒长的十分之一时才能保证有一定的准确度;瞄点式亮度计带有目镜瞄准系统,视场立体角可变换,并且可以调焦,测量准确度较高,但它的测量范围很小,只能测量瞄准点处的亮度,并且操作比较繁琐;CCD成像亮度计允许同时对空间上相关联的多个点进行亮度测量,它采用与CIE匹配的三色滤光片进行亮度和色度测量,可以显示图像中每个像素的CIE色坐标和色温,数秒内摄取数百万亮度数据信息,它的原理是利用光谱相应特性与观察者光视效率函数一致的CCD光电耦合器件,通过光学系统同时获取发光体的光辐射强度和图像,再经线性信号处理系统,可得到测量视场中被检测目标的亮度结果,CCD成像亮度计的测量范围较大,精度也比较高,但它在测量时仍然需要事先进行对焦,无法直接得到空间的亮度分布信息。目前,针对全空间亮度分布数据的测量并没有相应的解决方案,所做的研究很少并且缺乏系统性。The research on luminance measurement has a long history, and some results have been achieved. Currently, there are many kinds of luminance meters available on the market. The more common photometers include shading tube photometer, aiming point photometer and CCD imaging photometer. Among them, the shading tube photometer is characterized by simple manufacture and convenient use. The disadvantage is that its measurement accuracy is not high, and the detection The receiving surface of the receiver is very small, and certain accuracy can be guaranteed only when the radius of the small hole of the cylinder is less than one-tenth of the length of the cylinder; Focusing, the measurement accuracy is high, but its measurement range is small, it can only measure the brightness at the aiming point, and the operation is cumbersome; the CCD imaging brightness meter allows simultaneous brightness measurement of multiple points related in space, It uses three-color filters matched with CIE for luminance and chromaticity measurement, which can display the CIE color coordinates and color temperature of each pixel in the image, and capture millions of luminance data information in seconds. Its principle is to use the corresponding characteristics of the spectrum The CCD photoelectric coupling device, which is consistent with the optical efficiency function of the observer, simultaneously obtains the light radiation intensity and image of the illuminant through the optical system, and then through the linear signal processing system, the brightness of the detected target in the measurement field of view can be obtained. CCD imaging The luminance meter has a large measurement range and high precision, but it still needs to be focused in advance during measurement, and cannot directly obtain the spatial luminance distribution information. At present, there is no corresponding solution for the measurement of full-spatial luminance distribution data, and the research done is few and lacks systematic.

发明内容SUMMARY OF THE INVENTION

发明目的:本发明提出一种基于空间光场的亮度测试系统及方法,测量全空间亮度分布数据。Purpose of the invention: The present invention proposes a brightness testing system and method based on a spatial light field to measure full-space brightness distribution data.

技术方案:本发明采用的技术方案为一种基于空间光场的亮度测试系统,包括成像模块和主机,所述成像模块包括光轴平行的主透镜和微透镜阵列,微透镜阵列的另一侧设有光电耦合器,光电耦合器所得信号数据再由主机计算出空间光场的亮度。Technical solution: The technical solution adopted in the present invention is a brightness test system based on a spatial light field, including an imaging module and a host, the imaging module includes a main lens with parallel optical axes and a microlens array, and the other side of the microlens array A photo-coupler is provided, and the signal data obtained by the photo-coupler is then calculated by the host to calculate the brightness of the spatial light field.

所述微透镜阵列位于主透镜焦平面处,所述光电耦合器位于微透镜阵列焦平面处。The microlens array is located at the focal plane of the main lens, and the optocoupler is located at the focal plane of the microlens array.

一种基于时域变换法空间光场亮度测试方法,包括光轴平行的主透镜和微透镜阵列,微透镜阵列的另一侧设有CCD,包括以下步骤:A method for measuring the brightness of a space light field based on a time-domain transformation method, comprising a main lens with parallel optical axes and a microlens array, and a CCD is arranged on the other side of the microlens array, comprising the following steps:

1)利用点亮度计对CCD进行图像灰度值与亮度值的标定;1) Use the point luminance meter to calibrate the image gray value and luminance value of the CCD;

2)确定重对焦平面与微透镜阵列的距离关系,将光场坐标双平面参数化;2) Determine the distance relationship between the refocusing plane and the microlens array, and parameterize the light field coordinate biplane;

3)建立主透镜平面、CCD平面、重聚焦平面的二维几何关系;3) Establish the two-dimensional geometric relationship of the main lens plane, the CCD plane, and the refocusing plane;

4)将上述二维几何关系拓展到四维光场;4) Extend the above two-dimensional geometric relationship to a four-dimensional light field;

5)将四维光场对主透镜平面进行积分,得到重聚焦平面的图像;5) Integrate the four-dimensional light field on the main lens plane to obtain an image of the refocusing plane;

6)根据事先标定好的图像灰度与亮度的对应关系对得到的重对焦图像进行再处理,将其转换为所需焦平面上的亮度分布图。6) Reprocessing the obtained refocusing image according to the pre-calibrated correspondence between the grayscale and the brightness of the image, and converting it into a brightness distribution map on the required focal plane.

所述步骤2)中将主透镜平面视为u-v面,将CCD平面视为x-y面,两平面之间的距离F即是主透镜的焦长,L表示入射光线强度,入射光线记为L(u,v,x,y)。In the step 2), the main lens plane is regarded as the u-v plane, the CCD plane is regarded as the x-y plane, the distance F between the two planes is the focal length of the main lens, L represents the intensity of the incident light, and the incident light is recorded as L ( u,v,x,y).

所述步骤3)中光线通过主透镜平面位置(u,v),之后到达CCD平面位置(x,y),最后到达重聚焦平面,在二维情况下,其几何关系为:In the step 3), the light passes through the main lens plane position (u, v), then reaches the CCD plane position (x, y), and finally reaches the refocusing plane. In the two-dimensional case, its geometric relationship is:

上式中LF(x,u)表示全光函数,特指某一条光线。LαF表示同一条光线在重聚焦平面上的交点,F'为主透镜到重聚焦平面的距离。In the above formula, L F (x, u) represents the plenoptic function, which refers to a certain ray in particular. L αF represents the intersection of the same ray on the refocusing plane, F' is the distance from the main lens to the refocusing plane.

所述步骤4)中将二维情况下的转换关系拓展到四维光场:In the step 4), the conversion relationship in the two-dimensional case is extended to a four-dimensional light field:

其中F'为主透镜平面到重聚焦平面的距离。where F' is the distance from the main lens plane to the refocusing plane.

所述步骤5)中将四维光场对(u,v)进行积分,得到重聚焦平面的图像EαF(x,y):In the step 5), the four-dimensional light field pair (u, v) is integrated to obtain the image E αF (x, y) of the refocusing plane:

一种基于傅里叶切片算法空间光场亮度测试方法,包括光轴平行的主透镜和微透镜阵列,微透镜阵列的另一侧设有CCD,包括以下步骤:A method for testing the brightness of a space light field based on a Fourier slice algorithm, comprising a main lens with parallel optical axes and a microlens array, the other side of the microlens array is provided with a CCD, and includes the following steps:

1)利用点亮度计对CCD进行图像灰度值与亮度值的标定;1) Use the point luminance meter to calibrate the image gray value and luminance value of the CCD;

2)将光场坐标双平面参数化;2) Parameterize the light field coordinate biplane;

3)在频域中提取适当的二维切片;3) Extract appropriate two-dimensional slices in the frequency domain;

4)再做二维傅里叶逆变换,得到重对焦平面上的图像;4) Do two-dimensional inverse Fourier transform again to obtain the image on the refocusing plane;

5)最后获得重对焦图像后,根据事先标定好的图像灰度与亮度的对应关系对得到的重对焦图像进行再处理,将其转换为相应焦平面上的亮度分布图。5) After the refocusing image is finally obtained, the obtained refocusing image is reprocessed according to the pre-calibrated correspondence between image grayscale and brightness, and is converted into a brightness distribution map on the corresponding focal plane.

所述步骤2)中将主透镜平面视为u-v面,将重聚焦平面视为x-y面,主透镜平面和CCD平面之间的距离F即是主透镜的焦长,入射光线记为L(u,v,x,y)。In the step 2), the main lens plane is regarded as the u-v plane, the refocusing plane is regarded as the x-y plane, the distance F between the main lens plane and the CCD plane is the focal length of the main lens, and the incident light is recorded as L (u ,v,x,y).

所述步骤3)及4)中令重聚焦平面距主透镜平面的距离为F′,即αF,光线与重聚焦平面的交点为(x,y),记为LαF,则光线与CCD平面的交点坐标即为(u+(x-u)/α,v+(y-v)/α);In the steps 3) and 4), let the distance between the refocusing plane and the main lens plane be F', that is, αF, the intersection of the light ray and the refocusing plane is (x, y), denoted as L αF , then the light ray and the CCD plane The coordinates of the intersection point are (u+(xu)/α, v+(yv)/α);

定义Pα为光场从CCD深度F转换到αF的转换因子,则Pα[LF]表示Pα作用于光场LF,由空间投影至二维平面:Define P α as the conversion factor of the light field from the CCD depth F to αF, then P α [L F ] means that P α acts on the light field L F and is projected from space to a two-dimensional plane:

根据傅里叶切片定理,上式可定义为:According to the Fourier slice theorem, the above formula can be defined as:

其中,为积分因子,对四维函数的后两维进行积分,Bα为四维基变换:in, is the integration factor, the last two dimensions of the four-dimensional function are integrated, and B α is the four-dimensional transformation:

定义切片因子以及Fn为N维傅里叶变换,F-n为N维傅里叶逆变换,将替换为可得:define slice factor And F n is the N-dimensional Fourier transform, F -n is the N-dimensional inverse Fourier transform, and the replace with Available:

可得:make Available:

其中βα的计算方法为:The calculation method of βα is:

由EF=Pα[LF]得到重聚焦后的图像。The refocused image is obtained by E F = P α [L F ].

有益效果:本发明结合了光场测量原理与传统亮度计的测量原理,通过成像模块实时获取空间光场分布信息,采集的数据更完整。而利用传统亮度计的标定方法事先对CCD进行标定,以此计算关系为图像灰度与亮度的对应关系,进而通过光场重聚焦算法得到所需焦平面上的图像,再将其转换成相应平面上的亮度分布,通过调整重聚焦的相关参数可以得到不同焦平面的图像及其亮度分布,在测量亮度时不需要进行对焦,操作十分简便,并且可以快速、实时捕捉空间亮度信息,匹配不同的测量需求。Beneficial effects: the present invention combines the light field measurement principle and the traditional luminance meter measurement principle, obtains the spatial light field distribution information in real time through the imaging module, and the collected data is more complete. The traditional luminance meter calibration method is used to calibrate the CCD in advance, and the calculated relationship is the corresponding relationship between the image grayscale and the brightness, and then the image on the required focal plane is obtained through the light field refocusing algorithm, and then converted into the corresponding The brightness distribution on the plane, by adjusting the relevant parameters of refocusing, the images of different focal planes and their brightness distribution can be obtained. When measuring the brightness, it is not necessary to focus, the operation is very simple, and the spatial brightness information can be quickly and real-time captured, matching different measurement needs.

附图说明Description of drawings

图1为本发明测试系统的结构示意图;Fig. 1 is the structural representation of the test system of the present invention;

图2为成像模块的结构示意图;2 is a schematic structural diagram of an imaging module;

图3为光场坐标双平面参数化示意图;Fig. 3 is a schematic diagram of biplane parameterization of light field coordinates;

图4为重聚焦平面与微透镜阵列的位置关系图。FIG. 4 is a diagram showing the positional relationship between the refocusing plane and the microlens array.

具体实施方式Detailed ways

下面结合附图和具体实施例,进一步阐明本发明,应理解这些实施例仅用于说明本发明而不用于限制本发明的范围,在阅读了本发明之后,本领域技术人员对本发明的各种等同形式的修改均落于本申请所附权利要求所限定的范围。Below in conjunction with the accompanying drawings and specific embodiments, the present invention will be further clarified. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. Modifications of equivalent forms all fall within the scope defined by the appended claims of this application.

实施例1Example 1

光场是用来描述光在三维空间中的辐射传输特性的概念,一般来说用光线与两个平面的交点坐标以及光线强度表示光场的一个采样点,也就是一条光线。A light field is a concept used to describe the radiative transfer characteristics of light in three-dimensional space. Generally speaking, a sampling point of the light field, that is, a ray, is represented by the coordinates of the intersection of the light and two planes and the intensity of the light.

如图1所示,本实施例基于空间光场的亮度测试系统包括主机2和成像模块1。所述成像模块1又包括光轴重合的主透镜3和微透镜阵列4,在微透镜阵列4另一侧还设有垂直于光轴的光电耦合器5,也就是CCD,如图2所示。所述微透镜阵列4的分辨率为434*625,相邻微透镜的间距为14um,所述光电耦合器5的分辨率在7000*5000以上。微透镜阵列4位于主透镜3焦平面上,光电耦合器5位于微透镜阵列4的焦平面上。As shown in FIG. 1 , the brightness testing system based on the spatial light field in this embodiment includes a host 2 and an imaging module 1 . The imaging module 1 further includes a main lens 3 and a microlens array 4 with coincident optical axes, and a photocoupler 5 perpendicular to the optical axis is also provided on the other side of the microlens array 4, that is, a CCD, as shown in FIG. 2 . . The resolution of the microlens array 4 is 434*625, the distance between adjacent microlenses is 14um, and the resolution of the optocoupler 5 is above 7000*5000. The microlens array 4 is located on the focal plane of the main lens 3 , and the optocoupler 5 is located on the focal plane of the microlens array 4 .

所述光电耦合器5在使用前事先利用点亮度计对其进行图像灰度值与亮度值的标定,灰度值范围为0~255,亮度值范围为0~1000cd/m2The photoelectric coupler 5 is calibrated with a point luminance meter for image grayscale value and luminance value before use. The grayscale value ranges from 0 to 255 and the luminance value ranges from 0 to 1000cd/m 2 .

成像模块1对待测场景进行拍摄,不同方向的光线经过主透镜3进入相机内部,汇聚到微透镜阵列4的不同微透镜上,经过微透镜后又发散成若干条光线分别到达光电耦合器5,由光电耦合器5接收后转换成电信号,该电信号发送至主机2进行处理。The imaging module 1 shoots the scene to be tested. Lights from different directions enter the camera through the main lens 3, converge on different microlenses of the microlens array 4, and then diverge into several light rays after passing through the microlens to reach the optocoupler 5 respectively. After being received by the photocoupler 5, it is converted into an electrical signal, and the electrical signal is sent to the host 2 for processing.

主机2按照光场重对焦原理对接收到的信号进行处理,若对精度要求较高,对运行时间要求相对较低,主机2采用时域变换法对原始光场进行重对焦,利用光线追迹的原理进行坐标变换,在新的像面上进行积分即得到对应焦平面上的图像。首先确定重对焦平面与微透镜阵列4的距离关系。The host 2 processes the received signal according to the principle of light field refocusing. If the requirements for accuracy are high and the running time requirements are relatively low, the host 2 uses the time domain transformation method to refocus the original light field, and uses ray tracing to refocus the original light field. The principle of coordinate transformation is carried out, and the image on the corresponding focal plane is obtained by integrating on the new image plane. First, the distance relationship between the refocusing plane and the microlens array 4 is determined.

如图3所示,接着将光场坐标双平面参数化,将主透镜平面视为u-v面,将CCD平面视为x-y面,两平面之间的距离F即是主透镜的焦长,入射光线通过双平面,交于点(u,v,x,y),L表示光线强度,则此光线记为L(u,v,x,y),其中(x,y)代表光线与CCD平面交点的坐标,也是每个微透镜的位置(因为微透镜焦距很小,微透镜阵列4与光电耦合器6接近至距离可忽略);(u,v)为光线与主透镜平面交点的坐标。As shown in Figure 3, the light field coordinates are then parameterized in two planes, the main lens plane is regarded as the u-v plane, the CCD plane is regarded as the x-y plane, the distance F between the two planes is the focal length of the main lens, and the incident light Passing through the double plane, intersecting at the point (u, v, x, y), L represents the light intensity, then the light is recorded as L(u, v, x, y), where (x, y) represents the intersection of the light and the CCD plane The coordinates are also the position of each microlens (because the focal length of the microlens is small, the microlens array 4 and the optocoupler 6 are close to a negligible distance); (u, v) are the coordinates of the intersection of the light ray and the main lens plane.

进一步,根据主透镜平面、CCD平面、重聚焦平面的几何关系,光线通过主透镜平面位置(u,v),之后到达CCD平面位置(x,y),最后到达重聚焦平面,在二维情况下,其几何关系为:Further, according to the geometric relationship between the main lens plane, the CCD plane, and the refocusing plane, the light passes through the main lens plane position (u, v), then reaches the CCD plane position (x, y), and finally reaches the refocusing plane. In the two-dimensional case The geometric relationship is as follows:

上式中LF(x,u)表示全光函数,特指某一条光线。LαF表示同一条光线在重聚焦平面上的交点。In the above formula, L F (x, u) represents the plenoptic function, which refers to a certain ray in particular. L αF represents the intersection of the same ray on the refocusing plane.

进一步地,将二维情况下的转换关系拓展到四维光场:Further, the conversion relationship in the two-dimensional case is extended to the four-dimensional light field:

其中F'为主透镜平面到重聚焦平面的距离。in F' is the distance from the main lens plane to the refocusing plane.

最后将四维光场对(u,v)进行积分,得到重聚焦平面的图像EαF(x,y):Finally, the four-dimensional light field is integrated on (u, v) to obtain the image E αF (x, y) of the refocusing plane:

获得重对焦图像EαF(x,y)后,主机2根据事先标定好的图像灰度与亮度的对应关系对得到的重对焦图像进行再处理,将其转换为所需焦平面上的亮度分布图,并记录相关的亮度数据,根据用户的需求进行数据导出。After obtaining the refocusing image E αF (x, y), the host 2 reprocesses the obtained refocusing image according to the pre-calibrated correspondence between image grayscale and brightness, and converts it into the brightness distribution on the required focal plane. Figure, and record the relevant brightness data, and export the data according to the user's needs.

实施例2Example 2

若要求运行速度快,而对精度要求相对不高,则主机2采用频域傅里叶切片算法对原始光场进行重对焦,其原理为首先对原始空间光场做四维傅里叶变换,之后在频域中提取适当的二维切片,之后再做二维傅里叶逆变换,得到对应焦平面上的图像。If the running speed is required to be fast, but the accuracy requirements are relatively low, the host 2 uses the frequency domain Fourier slice algorithm to refocus the original light field. The principle is to first perform a four-dimensional Fourier transform on the original space light field, and then The appropriate two-dimensional slices are extracted in the frequency domain, and then the two-dimensional inverse Fourier transform is performed to obtain the image on the corresponding focal plane.

如图4所示,本实施例将主透镜平面视为u-v面,将重聚焦平面视为x-y面,主透镜平面和CCD平面之间的距离F即是主透镜的焦长,光线通过主透镜平面和重聚焦平面,与四维空间交于点(u,v,x,y),则此光线记为L(u,v,x,y)。As shown in Figure 4, in this embodiment, the main lens plane is regarded as the u-v plane, the refocusing plane is regarded as the x-y plane, the distance F between the main lens plane and the CCD plane is the focal length of the main lens, and the light passes through the main lens. The plane and the refocusing plane intersect the four-dimensional space at the point (u,v,x,y), then this ray is recorded as L(u,v,x,y).

接着令重聚焦平面距主透镜平面的距离为F′,即αF,光线与重聚焦平面的交点为(x,y),记为LαF。根据三角形相似定理,光线与CCD平面的交点坐标即为(u+(x-u)/α,v+(y-v)/α)。Next, let the distance between the refocusing plane and the main lens plane be F', namely αF, and the intersection of the ray and the refocusing plane be (x, y), denoted as L αF . According to the triangle similarity theorem, the coordinates of the intersection of the ray and the CCD plane are (u+(xu)/α, v+(yv)/α).

进一步,定义Pα为光场从CCD深度F转换到αF的转换因子,则Pα[LF]表示Pα作用于光场LF,目的是计算光场相机聚焦在对应深度的照片,即由空间投影至二维平面:Further, define P α as the conversion factor of the light field from the CCD depth F to αF, then P α [L F ] means that P α acts on the light field LF , and the purpose is to calculate the photo that the light field camera focuses on at the corresponding depth, namely Project from space to a 2D plane:

根据傅里叶切片定理,上式可定义为:According to the Fourier slice theorem, the above formula can be defined as:

其中,为积分因子,对四维函数的后两维进行积分,Bα为四维基变换:in, is the integration factor, the last two dimensions of the four-dimensional function are integrated, and B α is the four-dimensional transformation:

进一步定义切片因子以及Fn为N维傅里叶变换,F-n为N维傅里叶逆变换,将替换为可得:Further define the slice factor And F n is the N-dimensional Fourier transform, F -n is the N-dimensional inverse Fourier transform, and the replace with Available:

可得:make Available:

其中βα的计算方法为:The calculation method of βα is:

由EF=Pα[LF]得到重聚焦后的图像。The refocused image is obtained by E F = P α [L F ].

最后获得重对焦图像后,主机2根据事先标定好的图像灰度与亮度的对应关系对得到的重对焦图像进行再处理,将其转换为相应焦平面上的亮度分布图,并记录相关的亮度数据,根据用户的需求进行数据导出。After the refocusing image is finally obtained, the host 2 reprocesses the obtained refocusing image according to the pre-calibrated correspondence between image grayscale and brightness, converts it into a brightness distribution map on the corresponding focal plane, and records the relevant brightness Data, export data according to the needs of users.

Claims (10)

1.一种基于空间光场的亮度测试系统,其特征在于,包括成像模块(1)和主机(2),所述成像模块(1)包括光轴平行的主透镜(3)和微透镜阵列(4),微透镜阵列(4)的另一侧设有光电耦合器(5),光电耦合器(5)所得信号数据再由主机(2)计算出空间光场的亮度。1. A brightness testing system based on a spatial light field, characterized in that it comprises an imaging module (1) and a host (2), the imaging module (1) comprising a main lens (3) and a microlens array with parallel optical axes (4), the other side of the microlens array (4) is provided with a photocoupler (5), and the signal data obtained by the photocoupler (5) is then used to calculate the brightness of the spatial light field by the host (2). 2.根据权利要求1所述的基于空间光场的亮度测试系统,其特征在于,所述微透镜阵列(4)位于主透镜(3)焦平面处,所述光电耦合器(5)位于微透镜阵列(4)焦平面处。2. The brightness test system based on spatial light field according to claim 1, wherein the microlens array (4) is located at the focal plane of the main lens (3), and the optocoupler (5) is located at the microlens (3) focal plane. at the focal plane of the lens array (4). 3.一种基于时域变换法空间光场亮度测试方法,包括光轴平行的主透镜和微透镜阵列,微透镜阵列的另一侧设有CCD,其特征在于,包括以下步骤:3. a method for measuring the brightness of space light field based on time-domain transformation method, comprising the main lens and the microlens array that are parallel to the optical axis, and the other side of the microlens array is provided with a CCD, is characterized in that, comprises the following steps: 1)利用点亮度计对CCD进行图像灰度值与亮度值的标定;1) Use the point luminance meter to calibrate the image gray value and luminance value of the CCD; 2)确定重对焦平面与微透镜阵列的距离关系,将光场坐标双平面参数化;2) Determine the distance relationship between the refocusing plane and the microlens array, and parameterize the light field coordinate biplane; 3)建立主透镜平面、CCD平面、重聚焦平面的二维几何关系;3) Establish the two-dimensional geometric relationship of the main lens plane, the CCD plane, and the refocusing plane; 4)将上述二维几何关系拓展到四维光场;4) Extend the above two-dimensional geometric relationship to a four-dimensional light field; 5)将四维光场对主透镜平面进行积分,得到重聚焦平面的图像;5) Integrate the four-dimensional light field on the main lens plane to obtain an image of the refocusing plane; 6)根据事先标定好的图像灰度与亮度的对应关系对得到的重对焦图像进行再处理,将其转换为所需焦平面上的亮度分布图。6) Reprocessing the obtained refocusing image according to the pre-calibrated correspondence between the grayscale and the brightness of the image, and converting it into a brightness distribution map on the required focal plane. 4.根据权利要求3所述的基于时域变换法空间光场亮度测试方法,其特征在于,所述步骤2)中将主透镜平面视为u-v面,将CCD平面视为x-y面,两平面之间的距离F即是主透镜的焦长,L表示入射光线强度,入射光线记为L(u,v,x,y)。4. according to claim 3, it is characterized in that, in described step 2), main lens plane is regarded as u-v plane, CCD plane is regarded as x-y plane, two planes The distance F is the focal length of the main lens, L represents the intensity of the incident light, and the incident light is recorded as L(u, v, x, y). 5.根据权利要求4所述的基于时域变换法空间光场亮度测试方法,其特征在于,所述步骤3)中光线通过主透镜平面位置(u,v),之后到达CCD平面位置(x,y),最后到达重聚焦平面,在二维情况下,其几何关系为:5. according to claim 4, it is characterized in that, in described step 3), light passes through main lens plane position (u, v), then reaches CCD plane position (x ,y), and finally reach the refocusing plane. In the two-dimensional case, its geometric relationship is: 上式中LF(x,u)表示全光函数,特指某一条光线。LαF表示同一条光线在重聚焦平面上的交点,F'为主透镜到重聚焦平面的距离。In the above formula, L F (x, u) represents the plenoptic function, which refers to a certain ray in particular. L αF represents the intersection of the same ray on the refocusing plane, F' is the distance from the main lens to the refocusing plane. 6.根据权利要求5所述的基于时域变换法空间光场亮度测试方法,其特征在于,所述步骤4)中将二维情况下的转换关系拓展到四维光场:6. according to claim 5, it is characterized in that, in described step 4), the conversion relation under the two-dimensional situation is extended to four-dimensional light field: 其中F'为主透镜平面到重聚焦平面的距离。where F' is the distance from the main lens plane to the refocusing plane. 7.根据权利要求6所述的基于时域变换法空间光场亮度测试方法,其特征在于,所述步骤5)中将四维光场对(u,v)进行积分,得到重聚焦平面的图像EαF(x,y):7. The method for testing the brightness of space light field based on time domain transformation method according to claim 6, is characterized in that, in described step 5), four-dimensional light field is integrated to (u, v) to obtain the image of the refocusing plane E αF (x,y): 8.一种基于傅里叶切片算法空间光场亮度测试方法,包括光轴平行的主透镜和微透镜阵列,微透镜阵列的另一侧设有CCD,其特征在于,包括以下步骤:8. A method for testing the brightness of space light field based on Fourier slice algorithm, comprising a main lens parallel to the optical axis and a microlens array, and the other side of the microlens array is provided with a CCD, and is characterized in that, comprising the following steps: 1)利用点亮度计对CCD进行图像灰度值与亮度值的标定;1) Use the point luminance meter to calibrate the image gray value and luminance value of the CCD; 2)将光场坐标双平面参数化;2) Parameterize the light field coordinate biplane; 3)在频域中提取适当的二维切片;3) Extract appropriate two-dimensional slices in the frequency domain; 4)再做二维傅里叶逆变换,得到重对焦平面上的图像;4) Do two-dimensional inverse Fourier transform again to obtain the image on the refocusing plane; 5)最后获得重对焦图像后,根据事先标定好的图像灰度与亮度的对应关系对得到的重对焦图像进行再处理,将其转换为相应焦平面上的亮度分布图。5) After the refocusing image is finally obtained, the obtained refocusing image is reprocessed according to the pre-calibrated correspondence between image grayscale and brightness, and is converted into a brightness distribution map on the corresponding focal plane. 9.根据权利要求8所述的基于傅里叶切片算法空间光场亮度测试方法,其特征在于,所述步骤2)中将主透镜平面视为u-v面,将重聚焦平面视为x-y面,主透镜平面和CCD平面之间的距离F即是主透镜的焦长,入射光线记为L(u,v,x,y)。9. the method for testing the brightness of space light field based on Fourier slice algorithm according to claim 8, is characterized in that, in the described step 2), the main lens plane is regarded as the u-v plane, and the refocusing plane is regarded as the x-y plane, The distance F between the main lens plane and the CCD plane is the focal length of the main lens, and the incident light is recorded as L(u, v, x, y). 10.根据权利要求9所述的基于傅里叶切片算法空间光场亮度测试方法,其特征在于,所述步骤3)及4)中令重聚焦平面距主透镜平面的距离为F′,即αF,光线与重聚焦平面的交点为(x,y),记为LαF,则光线与CCD平面的交点坐标即为(u+(x-u)/α,v+(y-v)/α);10. The method for testing the brightness of space light field based on Fourier slice algorithm according to claim 9, wherein in described steps 3) and 4), the distance between the refocusing plane and the main lens plane is made to be F', that is, αF, the intersection of the ray and the refocusing plane is (x, y), denoted as L αF , then the coordinates of the intersection of the ray and the CCD plane are (u+(xu)/α, v+(yv)/α); 定义Pα为光场从CCD深度F转换到αF的转换因子,则Pα[LF]表示Pα作用于光场LF,由空间投影至二维平面:Define P α as the conversion factor of the light field from the CCD depth F to αF, then P α [L F ] means that P α acts on the light field L F and is projected from space to a two-dimensional plane: 根据傅里叶切片定理,上式可定义为:According to the Fourier slice theorem, the above formula can be defined as: 其中,为积分因子,对四维函数的后两维进行积分,Bα为四维基变换:in, is the integration factor, the last two dimensions of the four-dimensional function are integrated, and B α is the four-dimensional transformation: 定义切片因子以及Fn为N维傅里叶变换,F-n为N维傅里叶逆变换,将替换为可得:define slice factor And F n is the N-dimensional Fourier transform, F -n is the N-dimensional inverse Fourier transform, and the replace with Available: 可得:make Available: 其中βα的计算方法为:The calculation method of βα is: 由EF=Pα[LF]得到重聚焦后的图像。The refocused image is obtained by E F = P α [L F ].
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