CN101820501A

CN101820501A - Stable tracking method of television gate

Info

Publication number: CN101820501A
Application number: CN 201010128556
Authority: CN
Inventors: 赵金宇; 王斌; 贾建禄; 郭爽; 杨轻云; 吴元昊; 曹景太
Original assignee: Changchun Institute of Optics Fine Mechanics and Physics of CAS
Current assignee: Changchun Institute of Optics Fine Mechanics and Physics of CAS
Priority date: 2010-03-22
Filing date: 2010-03-22
Publication date: 2010-09-01

Abstract

The method for stabilizing the tracking of the TV wave gate of the present invention belongs to the technical field of TV closed-loop tracking of the photoelectric telescope. During the process of the TV closed-loop tracking of the space target, the tracking target is lost due to the non-tracking target passing through the wave gate or the shaking of the tracking target itself. . The method of the present invention obtains the speed vector of the target according to the position of the tracking target in the last three frames, as a benchmark for speed comparison; when multiple targets appear in the wave gate, the speed vectors between multiple targets in two adjacent frames are counted to form a speed Vector sequence; through the difference between the speed vector sequence and the reference speed, and calculate the modulus, the sequence of the value to be evaluated is obtained; the minimum value of the evaluation value is used as the criterion for tracking the target to realize the stable extraction and tracking of the tracking target. The beneficial effects of the present invention are: by performing statistical filtering on the velocity vectors of multiple targets in the wave gate, the influence of interfering targets can be eliminated, and the stability of the TV tracking process can be ensured.

Description

A Method for Steady Tracking of TV Wave Gate

技术领域technical field

本发明属于光电望远镜电视闭环跟踪技术领域，尤其涉及一种电视波门稳定跟踪的方法。The invention belongs to the technical field of photoelectric telescope and television closed-loop tracking, and in particular relates to a method for stably tracking a television wave gate.

背景技术Background technique

光电望远镜电视闭环的稳定跟踪广泛应用于空间目标探测、卫星发射场、常规靶场测量等领域。由于干扰目标的出现，往往导致电视跟踪中断，造成目标丢失，影响整个光电测量的效果。目前，国内在解决电视闭环稳定跟踪过程中的方法多采用最小二乘或卡尔曼预测滤波技术，计算复杂度高，难以保证对目标的实时提取。The stable tracking of photoelectric telescope and TV closed loop is widely used in space target detection, satellite launch site, conventional shooting range measurement and other fields. Due to the appearance of interfering targets, it often leads to the interruption of TV tracking, resulting in the loss of targets and affecting the effect of the entire photoelectric measurement. At present, domestic methods for solving the closed-loop stable tracking process of TV mostly use least squares or Kalman predictive filtering technology, which has high computational complexity and is difficult to guarantee real-time extraction of targets.

发明内容Contents of the invention

本发明的目的是提供一种电视波门稳定跟踪的方法，该方法通过对波门内多目标的速度矢量进行统计滤波，剔除干扰目标的影响，保证电视跟踪过程的平稳。The object of the present invention is to provide a method for stable tracking of a TV wave gate, which can eliminate the influence of interference targets by performing statistical filtering on the velocity vectors of multiple targets in the wave gate, so as to ensure the stability of the TV tracking process.

为了实现上述目的，本发明的技术方案如下：In order to achieve the above object, the technical scheme of the present invention is as follows:

光电望远镜在对空间目标进行电视闭环跟踪过程中，由于非跟踪目标穿越波门或跟踪目标本身的抖动，造成跟踪目标的丢失。本发明根据最近三帧跟踪目标的位置得到已知目标的速度矢量，做为速度比较的基准；当波门内出现多目标时，统计相邻两帧间所有目标的速度矢量，形成速度矢量序列；通过速度矢量序列与基准速度做差，并求模，得到待评估值的序列；以评估值的最小值作为跟踪目标的判据，实现对跟踪目标的稳定提取和跟踪。During the process of TV closed-loop tracking of space targets by photoelectric telescopes, the tracking targets are lost due to the non-tracking targets passing through the wave gate or the jitter of the tracking targets themselves. The present invention obtains the velocity vector of the known target according to the position of the tracking target in the last three frames, and uses it as a benchmark for velocity comparison; when multiple targets appear in the wave gate, the velocity vectors of all targets between two adjacent frames are counted to form a sequence of velocity vectors ; Make the difference between the speed vector sequence and the reference speed, and calculate the modulus, to obtain the sequence of the value to be evaluated; use the minimum value of the evaluation value as the criterion for tracking the target, and realize the stable extraction and tracking of the tracking target.

本发明的有益效果是：该方法简单，易于实现，能够保证对目标的实时提取和跟踪。The beneficial effects of the invention are: the method is simple, easy to implement, and can ensure real-time extraction and tracking of the target.

附图说明Description of drawings

图1是本发明电视波门稳定跟踪方法中的预处理流程图。Fig. 1 is a flow chart of preprocessing in the TV gate stabilization tracking method of the present invention.

图2是本发明电视波门稳定跟踪方法的流程图。Fig. 2 is a flow chart of the TV gate stabilization tracking method of the present invention.

图3是采用本发明电视波门稳定跟踪方法的跟踪目标序列的效果图。Fig. 3 is an effect diagram of the tracking target sequence using the TV gate stable tracking method of the present invention.

具体实施方式Detailed ways

下面结合附图和具体实施例对本发明做进一步详细地描述：Below in conjunction with accompanying drawing and specific embodiment the present invention is described in further detail:

本发明采用VC++6.0编程，运行环境为Windows XP，内存大于2G，硬盘大于80GB的计算机。The present invention adopts VC++6.0 programming, the operating environment is Windows XP, the memory is greater than 2G, the hard disk is greater than the computer of 80GB.

本发明电视波门稳定跟踪方法的流程如下：The flow process of TV wave gate stable tracking method of the present invention is as follows:

1)采集目标图像并进行预处理1) Collect the target image and preprocess it

如图1所示，在计算机内安装图像采集卡，安装CCD(Charge Coupled Device)相机采集软件，启动采集程序的线程，连续采集相机的图像，得到图像序列如下：As shown in Figure 1, install the image acquisition card in the computer, install the CCD (Charge Coupled Device) camera acquisition software, start the thread of the acquisition program, continuously acquire the images of the camera, and obtain the image sequence as follows:

{f(x_i，y_j，t_k)，f(x_i，y_j，t_k+1)，…，f(x_i，y_j，t_k+m-1}(i，j，k＝0，1...N) (1){f(x _i , y _j , t _k ), f(x _i , y _j , t _k+1 ),..., f(x _i , y _j , t _k+m-1 }(i, j, k =0,1...N) (1)

由于采集得到的图像的位数大于8位，不便处理，利用下式将图像转换为8位灰度图像，Since the number of digits of the collected image is greater than 8, it is inconvenient to process, and the image is converted into an 8-bit grayscale image using the following formula,

${f f}^{' '} (({x x}_{i i},, {y the y}_{j j},, {t t}_{k k})) = = \frac{255255}{(({f f}_{max max} - - {f f}_{min min}))} \times \times ((f f (({x x}_{i i},, {y the y}_{j j},, {t t}_{k k})) - - {f f}_{min min})),, ((i i,, j j,, k k = = 0,1 0,1 . . . . . . N N)) - - - - - - ((22))$

式中，f(x_i，y_j，t_k)-采集到的第k帧原始图像，In the formula, f( _xi , y _j , t _k )-the original image of the kth frame collected,

f′(x_i，y_j，t_k)-转换后的第k帧8位图像，f′(x _i , y _j , t _k ) - converted k-th frame 8-bit image,

f_max-采集到的第k帧原始图像最大灰度值，f _max - the maximum gray value of the original image of the kth frame collected,

f_min-采集到的第k帧原始图像最小灰度值。f _min - the minimum gray value of the kth frame of the original image collected.

对转换后的灰度图像按下式统计均值和方差，The mean and variance of the converted grayscale image are calculated according to the following formula,

$μ μ = = {Σ Σ}_{i i = = 00}^{N N} {Σ Σ}_{j j = = 00}^{M m} {f f}^{' '} (({x x}_{i i},, {y the y}_{j j},, {t t}_{k k})) / / ((N N \times \times M m)) - - - - - - ((33))$

$σ σ = = \sqrt{{Σ Σ}_{i i = = 00}^{N N} {Σ Σ}_{j j = = 00}^{M m} {(({f f}^{' '} (({x x}_{i i},, {y the y}_{j j},, {t t}_{k k})) - - u u))}^{22} / / ((N N \times \times M m))} - - - - - - ((44))$

式中，N×M-是单帧图像的像素个数。In the formula, N×M- is the number of pixels of a single frame image.

由于相机本身和天光背景的影响，采集到的图像噪声会较大，比较进行去噪处理。按图1中的第五步所示，采用中值滤波的方法。中值滤波的基本原理是把数字图像或数字序列中一点的值用该点的一个邻域中各点值的中值代替。这种处理方法的主要优点是能够去除图像的椒盐噪声和孤立噪声点。Due to the influence of the camera itself and the skylight background, the collected image noise will be relatively large, so it is better to perform denoising processing. As shown in the fifth step in Figure 1, the method of median filtering is adopted. The basic principle of median filtering is to replace the value of a point in a digital image or digital sequence with the median value of each point in a neighborhood of the point. The main advantage of this processing method is that it can remove the salt and pepper noise and isolated noise points of the image.

为便于后续处理，对图像进行二值化处理，二值化的处理过程：利用前面得到的图像的均值和方差给出一个全局阈值T(T＝μ+3σ)，将f′(x_i，y_j，t_k)＞T的像素点值设为255(白色)，其余的点都设为0(黑色)，实现二值化的目的。对二值化后的图像中白色点进行统计，如果存在灰度值为255，大小小于2×2＝4个像元的目标，则认为该目标为孤立点，直接将该点的灰度值付零。In order to facilitate subsequent processing, the image is binarized. The binarization process: use the mean and variance of the previously obtained image to give a global threshold T (T=μ+3σ), and f′( _xi , y _j , t _k )>T pixel value is set to 255 (white), and the rest of the points are set to 0 (black), to achieve the purpose of binarization. Count the white points in the binarized image. If there is a target with a gray value of 255 and a size smaller than 2×2=4 pixels, the target is considered to be an isolated point, and the gray value of the point is directly Pay zero.

得到二值化后的图像序列，如下所示：The binarized image sequence is obtained as follows:

{f″(x_i，y_j，t_k)，f″(x_i，y_j，t_k)，...f″(x_i，y_j，t_k)}(i，j，k＝0，1...N) (5){f″(x _i , y _j , t _k ), f″(x _i , y _j , t _k ),... f″(x _i , y _j , t _k )} (i, j, k= 0,1...N) (5)

2)目标识别步骤2) Target recognition step

对步骤1)得到的二值化后的图像序列进行逻辑运算，由于上述图像序列中的像素点值为0或255，用0或1即可表示。需要识别的卫星目标短时间内是点目标，而图像背景中的恒星是线状目标，对图像序列中的N取3，即取连续三帧图像进行操作，在逻辑上相邻两帧图像按位进行“与”操作，得到两幅包含目标的图像g(x_i，y_j，t_k)，g(x_i，y_j，t_k+1)，如下：Perform logic operations on the binarized image sequence obtained in step 1). Since the pixel value in the above image sequence is 0 or 255, it can be represented by 0 or 1. The satellite target that needs to be recognized is a point target in a short time, and the star in the image background is a linear target. Take 3 for N in the image sequence, that is, take three consecutive frames of images for operation, and logically adjacent two frames of images are pressed Perform "AND" operation on bits to get two images g( _xi , y _j , t _k ), g( _xi , y _j , t _k+1 ) containing the target, as follows:

g(x_i，y_j，t_k)＝f′(x_i，y_j，t_k+1)&f′(x_i，y_j，t_k)g(x _i , y _j , t _k )=f'(x _i , y _j , t _k+1 )&f'(x _i , y _j , t _k )

g(x_i，y_j，t_k+1)＝f′(x_i，y_j，t_k+2)&f′(x_i，y_j，t_k+1)g(x _i , y _j , t _k+1 )=f'(x _i , y _j , t _k+2 )&f'(x _i , y _j , t _k+1 )

继续对图像g(x_i，y_j，t_k)，g(x_i，y_j，t_k+1)按位进行“与”操作，则得到最终包含卫星目标的图像，如下：Continue to perform bitwise "AND" operation on the image g( _xi , y _j , t _k ), g( _xi , y _j , t _k+1 ), and finally get the image containing the satellite target, as follows:

B(x_i，y_j，t_k+1)＝g(x_i，y_j，t_k)&g(x_i，y_j，t_k+1) (6)B(x _i , y _j , t _k+1 )=g(x _i , y _j , t _k )&g(x _i , y _j , t _k+1 ) (6)

上述目标识别的方法简单易行，保证图像处理的实时性，抗干扰能力强。The above target recognition method is simple and easy to implement, ensures real-time image processing, and has strong anti-interference ability.

3)波门稳定跟踪步骤3) Gate stabilization tracking steps

通过连续三帧图像识别，波门自动套住跟踪的目标，只是得到了目标的初始位置，由于非跟踪目标(例如：恒星)穿越波门或跟踪目标本身的抖动，将造成跟踪目标的丢失，为保证波门始终稳定跟踪目标，需要进行一系列方法进行处理。如图2所示。Through image recognition of three consecutive frames, the wave gate automatically traps the tracked target, and only obtains the initial position of the target. Due to the non-tracked target (such as: a star) passing through the wave gate or the shaking of the tracked target itself, the tracked target will be lost. In order to ensure that the wave gate always tracks the target stably, a series of methods are required for processing. as shown in picture 2.

首先，根据初步识别出的目标位置(方位角度A_i、俯仰角度E_i，对应的起始时间t_i，计算目标方位和俯仰两个方向的基准速度，其中i是帧数：First, according to the preliminarily recognized target position (azimuth angle A _i , pitch angle E _i , and the corresponding start time t _{i )} , calculate the reference speed of the target in both directions of azimuth and pitch, where i is the number of frames:

V_A0＝(A_i+1-A_i)/(t_i+1-t_i)V _A0 ＝(A _i+1 -A _i )/(t _i+1 -t _i )

V_E0＝(E_i+1-E_i)/(t_i+1-t_i)V _E0 ＝(E _i+1 -E _i )/(t _i+1 -t _i )

其次，对连续三帧波门内的N个目标进行遍历，求得两个方向的速度矢量序列，其中，每两个目标位置得到的速度是：Secondly, traverse the N targets in the wave gate for three consecutive frames, and obtain the velocity vector sequence in two directions, where the velocity obtained for every two target positions is:

V_Ak＝(A_k+1-A_k)/(t_i+1-t_i)，V_Ek＝(E_k+1-E_k)/(t_i+1-t_i)，V _Ak =(A _k+1 -A _k )/(t _i+1 -t _i ), V _Ek =(E _k+1 -E _k )/(t _i+1 -t _i ),

其中，k是目标编号，k＝1，2，...N；i是图像帧数。Wherein, k is the target number, k=1, 2, . . . N; i is the number of image frames.

方位和俯仰方向各得到一个速度矢量序列，个数等于目标数N：Azimuth and pitch directions each get a velocity vector sequence, the number of which is equal to the number of targets N:

M_A1＝[V_A1，V_A2，...V_AN]；M_E1＝[V_E1，V_E2，...V_EN]M _A1 = [V _A1 , V _A2 , ... V _AN ]; M _E1 = [V _E1 , V _E2 , ... V _EN ]

得到的新的速度差绝对值的序列The resulting sequence of new absolute values of velocity differences

M′_A1＝[V′_A1，V′_A2，...V′_AN]；M′_E1＝[V′_E1，V′_E2，...V′_EN]M' _A1 = [V' _A1 , V' _A2 , ... V' _AN ]; M' _E1 = [V' _E1 , V' _E2 , ... V' _EN ]

分别统计M′_A1和M′_E1两个序列中的最小值，得到两个最小值的位置序号[A_i，E_j.]。Count the minimum values in the two sequences M′ _A1 and M′ _E1 respectively, and obtain the position numbers [A _i , E _j .] of the two minimum values.

统计得到的位置序号[A_i，E_j.]，如果i＝j，则确认该序号目标为跟踪目标。The position serial number [A _i , E _j .] obtained by statistics, if i=j, confirm that the target with this serial number is a tracking target.

这种基于速度差的统计滤波方法，计算量只有2N次，保证了计算的实时性和滤波的准确性。This statistical filtering method based on speed difference has only 2N times of calculation, which ensures the real-time calculation and the accuracy of filtering.

实施例：Example:

以某型口径为100mm光电望远镜跟踪卫星目标为例，CCD相机选用加拿大Andor公司的DV887，像素数为512×512，输出灰度为16位，图像采样时间为20ms，采集卡接口为PCI总线，方位和俯仰位置测量元件均选用24位绝对式编码器。为在上述设备上实施波门稳定跟踪，还需要准备的条件有：对相机调焦，保证空间目标在相机靶面上图像圆整性；利用卫星的轨道数据引导设备指向卫星，保证目标初始的位置在相机靶面内。Taking a certain type of photoelectric telescope with a caliber of 100mm to track satellite targets as an example, the CCD camera is DV887 from Andor Company in Canada, the number of pixels is 512×512, the output gray scale is 16 bits, the image sampling time is 20ms, and the interface of the acquisition card is PCI bus. Azimuth and elevation position measuring components are all selected 24-bit absolute encoders. In order to implement wavegate stable tracking on the above equipment, the conditions that need to be prepared are: focus the camera to ensure the roundness of the image of the space target on the camera target surface; use the orbit data of the satellite to guide the equipment to the satellite to ensure the initial position The position is within the target plane of the camera.

具体实施过程：首先按图1中的工作流程，采集图像，并对图像进行预处理工作，详细方法参见步骤1)；得到二值化后的图像序列后，按步骤2)的方法进行目标初始识别，得到目标在相机靶面上的初始位置；按图2中的流程进行波门稳定跟踪。图3给出了跟踪目标序列的效果图，在连续三帧波门跟踪过程中，不断有其它目标进入波门干扰对目标的提取，通过本发明波门稳定跟踪的方法实现了对目标的持续稳定跟踪过程。The specific implementation process: first, according to the workflow in Figure 1, collect images, and preprocess the images, see step 1) for detailed methods; after obtaining the binarized image sequence, perform target initialization according to step 2) Identify and obtain the initial position of the target on the camera target surface; perform gate stable tracking according to the process in Figure 2. Figure 3 shows the effect diagram of the tracking target sequence. During the continuous three-frame gate tracking process, other targets continue to enter the gate to interfere with the extraction of the target. The continuous tracking of the target is realized by the method of the gate stable tracking of the present invention. Stable tracking process.

Claims

1. a method for TV wave gate stable tracking, is characterized in that, the method comprises the steps:

During the TV closed-loop tracking process of the space target by the photoelectric telescope, the velocity vector of the known target is obtained according to the position of the tracking target in the last three frames, which is used as a benchmark for speed comparison; when multiple targets appear in the wave gate, count the adjacent two frames The speed vectors of all targets in between form a speed vector sequence; the difference between the speed vector sequence and the reference speed is calculated, and the sequence of values to be evaluated is obtained; the minimum value of the evaluation value is used as the criterion for tracking the target to realize the tracking Stable extraction and tracking of targets.