第一篇：《目标检测》作文
一、提建议：《目标检测》M1 1）.Dear Frank，There are a lot of things you should do.You should talk about it with your classmates.Maybe they just played a joke on you.Or maybe you should write a letter to your best friend if you think it is not easy for you to talk about it with others.Anyway, always be friendly to others and always smile to others!It is the best way to be popular!
Mary 2）（补充另一篇）...It's a good idea to watch English films and listen to real English songs.Try to read English newspapers and listen to English radio.They are good for your English.Try not to be shy when you start a conversation in English.Do you find it difficult to remember the English words? You should remember eight or ten words a day.How about placing the words on the wall or saying the English names for everything you see? Work hard, and you can learn English well.二、谈论爱好：《目标检测》M5 1)
Dear Miss Liu，My name is Lily.I’m 13years old.I’m from Class 1, Grade 8.I can play the violin.I began to play the violin at the age of 5.Now I can play it very well.I often take part in some competitions and I have won some prizes.I like music because I think music is very beautiful.It makes me happy.I also learn a lot from music.It improves my memory a lot.So I can remember English words easily.I hope I can play in our school orchestra.I believe I can do well.Yours，Lily
2)（补充另一篇）I like music very much because it can give me power when I am sad.People from different countries all like music very much.Music is very important for us.If there is no music is very important for us.If there is no music in the world, our life won't be so interesting.Pop music is my favourite.I think it sounds nice and it can make me feel relaxed.Jay Chou is my favourite singer.He is one of the most popular singers in Asia.三、介绍人物：《目标检测》M7
My friend Linda was born in Canada.She is 13 years old.She is a tall and thin girl with long hair.She is lovely and friendly.She has many hobbies, such as dancing and pop music.She also likes shopping and swimming, and reading is her favorite one.She usually invites me to go to the library at the weekend with her.There we read books and have fun together.This is my best friend.I love her.四、谈论规定：《目标检测》M12 Miss White, it is a notice to the audience.It says that we should walk into the cinema hall fifteen minutes before the movie starts.We mustn’t smoke or talk loudly in the cinema hall.We mustn’t take food or drinks into it.We can’t use the mobile phone after the movie is on.We can’t use the camera.(补充另一篇）Dear Jack, I am very happy that you will come to visit China.I'll tell you some customs in China.You must walk on the right.When you meet other people, you should say hello to them instead of bowing.When you eat, you must use chopsticks.When you have dinner with a Chinese family, the host often asks you to eat more food.You don't need to eat it up.After the dinner, the host often makes tea for you.It's delicious.Before you leave the house, you should say goodbye to the host politely.Waiting for you!Yours, Zhang Tao
第二篇：点目标检测
点目标检测问题是成像制导领域中的一个关键技术 ,国内 外对此提出过许多算法。文献[1 ,2 ]对传统算法进行介绍与综 述。总体而言 ,实时鲁棒的小目标自动检测技术尚未完全突 破 ,仍然是当今世界高技术领域的热门研究课题。目前这些传 统算法为了在低信噪比条件下实现对点目标较高的检测概率 , 往往需要较大的计算量和存储量。这些限制了具体算法在空 空导弹成像导引头上的应用 ,从而影响了成像导引头获得的更 大的截获和跟踪距离。
近年来 ,国内外学者利用数学形态学理论对点目标检测问
题进行了研究 ,并取得了一些成果。J.Barnett 在文献[ 3 ]中对 形态学方法与线性空间滤波方法进行了比较;Li Jicheng(李吉 成)等在文献[4 ]中提出利用目标图像尺寸的先念知识选择结 构元素消除背景而保留目标的方法;Horak文献[5 ]中提出了基 于灰度形态学 T op2hat 变换的弱目标检测方法 ,并在不含目标 的背景图像上构造所需要的结构元素;Rivest、罗贤龙、Zhu Zhen fu等人在文献[6～8 ]也分别对基于形态学的方法进行了 相应研究;熊辉等人在文献[9 ]中提出新的思路 ,其算法基于形 态学膨胀累加 ,实现对高空背景情况下抖动目标的检测 ,并对 抖动为1～2个像素的点目标进行5帧累加仿真。前人的研究 表明 ,形态学方法对点目标的检测具有很大的潜力。为此 ,我 们在对成像导引头进行分析的基础上 ,对形态学方法应用于成 像导引头进行研究。
由于空空导弹所攻击的目标具有很高机动能力和很宽的速度范围 ,所以其性能指标相对于其他红外系统有较大区别。取典型凝视成像导引头参数 ,进行仿真研究:帧频为 100f/ s ,瞬 时视场为3× 3° ,搜索角速度为 15° / s ,探测器阵列为 128 ×128。经过计算 ,可知在一帧时间内 ,导引头由于搜索而扫描过的角 度为0.15° ,即6.4 个像素。在 10km距离处 ,由导弹目标相对 运动引起的 ,目标图像在帧间位移1.55像素。这样 ,在对目标 截获时 ,由于导引头搜索和目标运动造成的目标图像总的帧间 位移最大值约为8 像素。仿真表明 ,在导弹发射后 ,导弹在目 标跟踪阶段 ,目标图像帧间位移约为 1～10 像素(导弹失控
前)。因此 ,目标图像帧间位移在整个导弹点目标搜索、截获与 跟踪过程中变化范围可认为在1～10像素。
仿真表明 ,利用现有基于形态学背景预测的方法进行点目
标检测和识别时 ,对背景均匀或起伏缓慢的情况效果很好。但 对于亮度梯度高的有云天空背景和地面背景 ,算法常常造成误 判。分析其原因 ,发现往往跟踪的是滤波后残留的高亮度背景 边角。
第三篇：八年级下册英语目标检测作文（xiexiebang推荐）
Module 1
My Favourite Teacher
I’ve got many good teachers.But my favourite one is our English teacher, Miss Lin.She’s about thirty years old and she looks very pretty.She is quite tall with short hair and a pair of glasses.She often wears jeans and T-shirt.She likes singing and doing sports.She works hard and she is very strict with us.She spends a lot of time taking care of us and helping us with our lessons.She often talks to us and encourages us when we get bad marks or do something wrong.Anyway, she is not only our good teacher but also our good friend.She is one of the best teachers in our school.I’m proud of her.Module 2
Dear Tony,How are you? I’m having a wonderful time in Beijing now.I have done many interesting things here.I have been to many places of interest.I have visited the Tian’anmen Square, the Palace Museum and the Great Wall.I have taken many nice photos of these famous places.I’ll send some to you with this email.I have also enjoyed different kinds of Chinese food.I’ve tried dumplings, noodles and roast duck.They are all very delicious.I think Beijing is one of the biggest and busiest cities in the world.There’s a lot to see and do here.I hope we can visit Beijing together next time.Yours,Tom
Module 3
Scientists think that there has been life on earth for hundreds of millions of years.Seven other planets go around the sun like the earth.However, none of them has an environment like that of the earth.So scientists do not think they will find life on them.The sun and its planets are called the solar system.And our solar system is a small part of a much larger group of stars and planets.We call it Galaxy.Scientists have also discovered many other galaxies in the universe.So it is impossible to imagine how large the universe is.We have always asked the question: With so many stars in the universe, are we alone? Is there life out there in the space? We’re looking forward to know the answer.Module 4
Health is very important for us all.In order to keep healthy, I always eat healthy food and do enough exercise.I have the three meals at home and I often eat vegetables and fruit, as well as meat and fish.After school, I often do some sports with my classmates, such as playing basketball and table tennis.In the evening, I go to bed early after I finish my homework.So I’m in excellent condition.Do you want to be as healthy as I? Here is some advice.First, stop eating fast food
and have healthy food.Second, don’t spend too much time in front of the computer.Try to do more exercise every day.Third, it’s good for your health to go to bed early in the evening.If you follow my advice, you will become healthier and healthier.Module 5
Milk and Coca are in the Sea
There are two main Characters, Milk and Coca, in my cartoon story.They are good friends.Milk is a lovely girl.She has a white face with two big eyes.She is not only kind, but also smart.She likes traveling in the sea.Coca is a cute boy.He has a black face with two small eyes.He is clever and helpful.He likes traveling in the sea, too.Both of them decide to have a trip in the sea, so they run away from their homes.In the sea they meet strange animals and sea plants.All of them are growing in the polluted water.After the trip they come back to ask people to pay attention to the environment and they accept their advice.I’m sure the story can win the hearts of many people with the interesting characters, beautiful pictures and the happy ending.Module 6
Dear Jane,Thanks for your letter.I’m very glad to talk about my hobby to you.I have a few hobbies, but my favorite one is going online.I started to go online when I was very young.Now I still enjoy it.I’ve learned a lot from the Internet and I can do a lot of things on it.For example, I can send emails and do shopping online.It helps me save time and money.I think hobbies can make us grow as a person, develop our interests and help us learn new skills.However, we shouldn’t spend all our free time on our favorite hobby.Best wishes!
Yours，John
Module 7
Dear Sir,I want to join in the summer camp.It’s a good way to improve my English and it can also help me learn more about the American culture at the same time.I like sports and pop music.I can use the Internet to get something useful.I do quite well in English and can talk with foreigners freely.As well as learning English, I want to experience life in the USA.I expect to live with an American family and take part in American life.Having meals with the family and doing some activities with them.I hope to stay in a large American family with three or four children.If they want to learn Chinese, I can help them a lot.I’m sure we’ll have a great time together.Thank you!
Yours,Meimei
Module 8
It was sunny last Saturday.I went to visit Beihai Park with my parents.There were so many people there and we stayed there for a whole day.The park is really large.It is 682,000 square meters.There are many interesting tourist spots there, such as White Pagoda, Qionghua Island and so on.The most famous one is White Pagoda.It has already become the symbol of Beihai Park.Beihai Park is one of the earliest buildings and the best gardens in the world.It is old, but beautiful.Every year, millions of visitors from different parts of the country and different parts of the world come to visit it.It has become more and more famous around the world.Module 9
My Best Friend
In our lives, we may have many friends.And good friends really mean a lot to us.One of my best friends is Mary.She is very kind and helpful.Two years ago, I came to this city with my parents.On the first day of my new school, I felt lonely because I had no friends.Just then, Mary came to talk to me.What’s more, she helped me with my English, too.Mary’s help made me feel happy and warm.As a result, we became friends soon.It was Mary who gave me the greatest help when I was new here.I think friendship is so important that it can help us feel happy and make our lives more beautiful.Module 10
My Hobby and My Future
Reading has become my hobby since I was young.I still remember I often asked my mother to tell me stories when I was a child.My mother taught me to read books at the age of five and I became interested in reading.As I grew older, my interest in reading grew.It seemed that I could communicate with the the characters in the books.With the help of reading, I became intersted in writing, too.Although I’m very busy at school, I enjoy writing about our lives at school and intersting stories around me.Many of my classmates love my stories.I hope I will write good books for the world in the futur and become a writer.I think my hobby will bring me both pleasure and success.期末2010-2011
Dear Tom,I’m very glad to hear from you.I like playing football, too, but my favourite hobby is reading storybooks.I always go over my lessons and do my homework first after I get back home every day.Then if I have enough free time, I will read my favourite storybooks.And it usually takes small pieces of time.In my opinion, good hobbies can make us grow as a person and they bring us enjoyment and success.However, we shouldn’t spend all our free time on hobbies.As a student, we must work hard at the schoolwork.I hope you will do well in your schoolwork while enjoying your favourite hobby soon.Best wishes!
Yours,Li Hua
模拟考试
According to the result, 75% students think homework is good for them.Doing homework can help them not only go over what they’ve learned but prepare for the next lessons.Also they can improve their learning skills by finishing homework.However, 25% students have different opinions.They think doing too much homework will take too much time, as a result, they can’t have a good rest and have no time for hobbies.In my opinion, it is necessary and helpful to do homework properly.I hope our
teachers should give us some creative homework , such as making posters with pictures, dreaming up new stories and giving interviews to the people around us.
第四篇：运动目标检测方法总结报告
摘要
由于计算机技术的迅猛发展，使得基于内容的视频信息的存取、操作和检索不仅成为一种可能，更成为一种需要。同时，基于内容的视频编码标准MPEG-4和基于内容的视频描述标准MPEG-7正在发展和完善。因此提取和视频中具有语义的运动目标是一个急需解决的问题。运动目标提取和检测作为视频和图像处理领域的重要研究领域，有很强的研究和应用价值。运动检测就是将运动目标从含有背景的图像中分离出来，如果仅仅依靠一种检测算法，难以从复杂的自然图像序列中完整地检测出运动的目标。较高的检测精度和效率十分重要，因此融合多种检测方法的研究越来越受到重视。本文介绍了几种国内外文献中的经典的视频运动目标的检测和提取算法，并对各种方法进行了评价和总结。首先介绍了基本的运动目标检测的基本知识和理论，然后介绍了基本的几种目标检测方法及其各种改进方法。对今后的运动目标检测提取的相关研究提供一定的参考。
关键词：运动目标检测 光流法 帧差法 背景建模方法
摘要 i
ABSTRACT Because of the rapid development of computer technology, it is possible to access, operate and retrieve the video information based on the content of the video.At the same time, based on the content of the video coding standard MPEG-4 and content-based video description standard MPEG-7 is developing and improving.Therefore, it is an urgent problem to be solved in the extraction and video.Moving object extraction and detection is a very important field of video and image processing, and has a strong research and application value.Motion detection is to separate moving objects from the image containing background, if only rely on a detection algorithm, it is difficult to from a complex natural image sequences to detect moving target.Higher detection accuracy and efficiency are very important, so the study of the fusion of multiple detection methods is becoming more and more important.In this paper, the detection and extraction algorithms of the classical video moving objects in the domestic and foreign literatures are introduced, and the methods are evaluated and summarized.Firstly, the basic knowledge and theory of basic moving target detection is introduced, and then the basic method of target detection is introduced.To provide a reference for the research on the extraction of moving target detection in the future.Keywords: Visual tracking
Optical flow method
Frame Difference
Background modeling method
ii ABSTRACT
目录
摘要...................................................................................................................................0 ABSTRACT.....................................................................................................................1 第一章 绪论....................................................................................................................3
1.1 研究背景及意义................................................................................................................4 1.2 研究现状............................................................................................................................4
第二章 经典的运动目标检测算法................................................................................5
2.1 光流法................................................................................................................................5 2.2 帧差法................................................................................................................................5 2.3 背景差分法........................................................................................................................7
第三章 改进的运动目标检测算法................................................................................9
3.1 改进的三帧差分法............................................................................................................9 3.2 帧间差分法与光流法结合..............................................................................................10 3.3 改进的背景建模算法......................................................................................................11
第四章 总结..................................................................................................................13 参考文献：....................................................................................................................16
目录 i 2 运动目标检测方法研究总结
第一章 绪论
1.1 研究背景及意义
近几十年来，在科学技术飞速发展的条件下，视频与图像处理技术不断提高，各种各样的视频监控产品已经走入了人们的视野，并且在给我们的生活带了很多方便。视频监控系统的研究技术涉及到视频图像处理、计算机视觉、模式识别以及人工智能等科学领域。视频监控系统多数要求监控人员长期盯着监控屏幕，进行人为的分析判断，这样容易因为监控人员的疏忽造成重要信息的遗漏。为此，人们开始将计算机领域的相关技术引入到视频监控系统中，形成智能监控系统[1,2,3,4]。智能监控系统可以在没有人为干预的条件下，利用计算机视觉的相关技术来对视频序列图像进行智能的分析，实现对运动目标的检测、跟踪、分类和识别等。现在，运动目标检测技术不仅应用在发电站、商场、银行、民宅、广场和火车站等公共场所的智能监控系统中，而且在其他的领域也有十分广泛的应用。
1.2 研究现状
目前，基于视频的运动目标检测算法主要有三种：光流法、帧差法和背景差分法，这三种算法都有各自的优缺点。1981 年，Horn 和 Schunck 通过将二维速度场与图像灰度相联系，从而引入了光流约束方程，得到一个计算光流的基本方法[5]。Meyer 等人[6]在对光流法进行了深入研究的基础上，提出在光流场中采用基于轮廓的跟踪方法，该方法在摄像机运动的情况下能够有效的对运动目标进行检测和跟踪。Barron 等人[7]通过使用简单而有效的门限，先分割图像，再计算光流，通过消除杂乱的背景光流来得到较好的目标光流。Roland 等人[8]利用相邻帧差，通过局部阈值的迭代松弛技术实现图像边缘的光滑滤波。甘明刚等人[9]提出一种三帧差分和边缘信息相结合的运动目标检测算法，该算法有效地改善了一些情况下帧间差分法会出现“双影现象”的问题。郝豪刚和陈佳琪等人[10]提出五帧差分法和景差分法相结合的运动目标检测算法，该算法利用背景差分法和帧间差分法性能上的互补来得较好的检测结果。背景差分法有均值法、中值法、核密度估计法、Surendra 背景更新、单高斯模型和混合高斯模型等，从 20 世纪以来，相继出现 第一章 绪论 1 了一批批成熟的背景差分法，Wren 等人[11]提出了单高斯模型，该方法在单一背景下能够获得较好的检测结果，但是不适合复杂背景。Stauffer 等人[12]在单高斯模型的基础上提出了混合高斯模型，混合高斯模型在外界环境比较复杂的条件下仍然可以得到很好的检测效果。左军毅等人[13]提出时间平均模型和混合高斯模型双模式切换式的运动目标检测算法。除了以上三种的算法外，还有一些学者尝试采用其他的算法进行运动目标检测，例如，郝志成和吴川等人[14]提出的基于稳定矩阵的动态图像运动目标检测算法，该算法通过在短时间内自动的感知背景变来快速的建立背景模型。近年来，越来越多的研究机构和学者都参与到基于视频的运动目标检测的研究之中，并提出很多有效的、新颖的方法。但是仍存在一些问题善待提高，所以找到一种检测精度高、鲁棒性好的运动目标检测算法依然是我们为之努力的方向。
运动目标检测方法研究总结
第二章 经典的运动目标检测算法
2.1 光流法
空间中物体的运动可以用运动场来描述，同样可以通过序列图像中不同图像的灰度分布差异体现图像平面变化，对比空间中的运动场，体现在图像上表现为光流场。在运动的某一个时刻，为图像中的各个像素点赋一个速度的矢量，这样就成为了一个图像的运动场。由于空间物体上的点与图像上的点通过投影关系可以一一对应，则根据各个像素点的速度矢量的变化特征可以对图像进行动态分析[16]。当图像中没有目标运动时，在整个图像区域中光流矢量的变化是连续的；而当图像中有运动目标时，图像的背景和目标就会有相对的运动，那么目标运动所形成的速度矢量必然和邻域背景速度矢量不同，由此能够检测出运动目标的位置。光流法利用图像的灰度信息的变化从序列图像中计算出速度场，然后加上一些约束条件，从而推出运动目标的运动参数和物体结构[17]。
光流法事先不需要知道场景的任何信息，就可以准确的计算出运动物体的速度。它不仅能应用于静态背景下的运动目标检测，而且可以用于摄像机运动的情况，实现动态背景下的运动目标检测。它的缺点是：光流法的特点是要进行迭代运算，精度越高需要的计算量就越大，因此，光流法的计算量大，运算时间长，是一种比较耗时的算法，很难满足工程上对实时性的要求；光流法的抗噪性能差，例如，当光照发生变化时，即使没有运动发生，光流仍然存在，会被误检测为有目标运动，同时，如果缺少足够的灰度级变化，目标运动物体很难被检测到；当三维物体的运动投影到二维的图像时，亮度会有变化，从而导致通过光流约束是计算不出平面某点的图像速度流；使用光流法对运动目标进行检测，需要特定的硬件设备的支持。已经有一些学者针对光流法所存在的缺点进行了改进，相信未来光流法能够得到更好的实际应用。
2.2 帧差法
帧差法[18]又叫时间差分法，它通过将视频序列图像中的当前帧与相邻帧所对 第二章 经典的运动目标检测算法 3 应的像素点的灰度值进行比较，然后找到差异，进而检测出运动目标[19]。在视频序列图像中，相邻的图像之间具有连续性，当视频图像中有运动目标时，由于运动目标的运动，相邻图像间的像素点灰度值差别就会较大，相反，当视频图像中没有运动目标时，相邻图像间的像素点素灰度值差别就会较小，帧差法就是利用视频图像的这一特性进行检测的，它是运动目标检测的最简单方法。帧差法是先用相邻两帧做差分运算，然后做二值化处理，从而检测出运动目标。帧差法的基本运算原理框图如下：
图2.1 帧差法基本原理
在二值化的差分图像中，取值为 0 的像素点代表变化较小或是无变化的区域，表示为背景区域；取值为 255 的像素点代表变化的区域，表示为运动目标。至此，大多数的运动目标的基本形状已经凸显出来了。为了能够精确的提取出运动目标，通常还需要经过形态学处理，例如，膨胀、腐蚀、开运算、闭运算等，将断点进行连接或者将多余的部分去掉等，从而获得更加准确的检测结果。
帧差法优点是算法简单、容易实现、检测速度较快、能满足系统对实时性的要求，而且一般相邻两帧的时间间隔比较短，因此对场景的光线变化不是特比敏感，对环境的自适应性较强。帧差法存在着两个主要的缺点：帧差法的检测结果与目标运动速度和相邻两帧间隔大小有关。如果运动目标速度过快且两帧时间间隔长，可能会出现运动目标在运动方向上前后分裂并拉长，出现“双影现象”，最坏的情况下可能发生同一个运动目标被检测为两个不同的目标。如果运动目标运动过慢且两帧时间间隔小，交叠的部分在两帧图像进行差分时会因差值过小而被误判为背景区域，但是事实上这部分并不是背景区域，由此会造成目标信息的丢失，我们称之为“空洞现象”，最坏的情况下可能发生目标完全重叠而不能被检测出来。
运动目标检测方法研究总结
2.3 背景差分法
背景差分法又叫做背景减除法，是固定场景中目标检测算法最长用的一种检测算法。在背景差分法中，视频图像分为背景图像和前景图像，该方法将视频图像中的当前图像与背景图片进行比较，也就是当前帧与背景帧进行差分运算，在运算结果中像素点的灰度值变化大的区域即为运动目标，因此我们也常常认为背景差分法是帧间差分法的一种特例。
背景差分法的运算原理框图如下：
图2.2 背景差分法基本原理框图
提取出运动目标区域之后，可能会存在噪声，可以对其进行后期处理，例如膨胀、腐蚀、连通域检测等操作，从而提取出较为准确的运动目标。背景差分法的优点是算法复杂度低，算法实现比较简单，可以满足系统的实时性要求，并且在运动目标检测时一般能够得到比较完整的特征数据。是目前最常用的一种运动目标检测方法，尤其适用于背景固定或背景缓变的场景。该方法对外界的环境变化非常敏感，例如场景中天气的变化，光线的改变，摄像机的颤动，树叶的摇动等等这些外界的干扰很容易使背景点被误判为目标点，因而影响了检测的精度。所以该方法的难点在于建立一个符合场景需求的背景模型，而且需要有一套算法对背景模型进行更新，使背景成为实时而准确的背景。检测效果好的背景模型往往都会比较复杂，运算量比较大，从而使得背景更新的速度减慢，无法实时地检测出运动目标。如果背景模型更新的速度非常慢，实际上背景在不断变化着，会 导致从背景模型得到的背景图像不是实时的背景图像。但是如果背景模型更新的速度过快，背景有时就会和当前图像非常相似，背景差分法就无法检测出运动物体。因此，建立一个合适的背景模型是背景差分法的关键部分，也是该算法的一个难点。第二章 经典的运动目标检测算法 3
运动目标检测方法研究总结
第三章 改进的运动目标检测算法
3.1 改进的三帧差分法
三帧差分法是对两帧差分法的改进，它可以有效的克服两帧差分法的一些缺点，例如，克服了两帧差分法中的“双影现象”，但是却不能改善“空洞现象”，而且当运动目标和背景区域这两部分的灰度值比较接近时，三帧差分法不能准确的检测出运动目标的轮廓.为了改善三帧差分法检测结果的边缘缺失的这个缺点，王霏等人尝试将改进的Sobel算子与三帧差分法相结合，因为图像的边缘信息不容易受噪声和亮度突变的影响。改进算法的关键是获得一个完整的运动目标的边缘轮廓，针对“空洞现象”，通过后期的形态学处理和连通性分析相结合的方法来改善这个问题[20]。
改进的三帧差分法的基本思想是：把三帧分成两组，分别求两帧差分图，进行膨胀处理之后分别和边缘检测结果图相“与”，将两个结果进行“或”运算，得到一个初步的检测结果。然后与三帧差分法的结果进行“或”运算，得到一个更加完整的检测结果。最后对检测结果进行后期处理，来达到改善“空洞现象”和去除噪声的目的。
(a)经典的两帧差分法
第三章 改进的运动目标检测算法 7
(b)经典的三帧差分法
(c)改进的三帧差分法
3.2 帧间差分法与光流法结合
光流法对噪声敏感，运动目标边缘以外附近的像素点没有运动，但光流值不是零，出现了“速度漂移”。使得光流法和超像素分割的分割结果虽然不错，但是需要调节的参数空间非常大，需要花费大量的时间来进行参数的调整，导致它的实用性较差。帧间差分法简单易行，利用当前帧与前一帧差分，当运动目标运动过快时提取出的物体往往会出现双影而且比实际要大，当运动过慢时又往往因无法检测出重叠部分而出现空洞。为此，我们在光流法和超像素分割方法的基础上，融合了帧间差分法来进一步快速的缩小需要调节的参数的范围，极大的减少了人工调节的工作量。在改进的方法中，贺丽丽等人结合光流法产生的结果和帧间差分法的结果来提取出大致的运动区域，然后利用超像素分割进行精确的提取[21]。
利用超像素分割后的结果label，对帧间差分法得到的结果s 进行进一步的提取，由于超像素分割将图像分割成许多含有相似特征的标记图label，首先我们需要知道s,即已经求出的前景区域中含有对应标记图中的哪些标记。当我们确定了前景区域所包含的标记后，就需要进一步的确定这些标记在s和label 中所包含的像素个数。对于s，我们统计出其前景区域中对应于标记图label 中每个标记i所包含的像素的个数为isn,标记图label中每个标记i所包含的像素的个数为n，我们认为isn与n 之间的关系，将成为提取前景目标最重要的衡量标准。如果它们的比值小于某一个值T 时，则将Label中对应于标记i的像素值设为0，否则,Label中对应于i的像素值设为 1。原始图像t 中对应于 Label中等于 0 的位置也标记为 0；因此我们得到了提取出的运动目标图。
运动目标检测方法研究总结
3.3 改进的背景建模算法
针对传统混合高斯背景建模算法，由于受到算法的限制，每个像素点的模型个数是固定不变的。后来，等人提出了基于最大似然估计的像素点背景模型个数自适应选择方法。但由于该方法人为地引入了负的先验系数，使得在更新过程中高斯成分的权重有可能被不合理地负更新。王永忠等人在传统混合高斯背景建模的基础上，提出一种了自适应选择混合高斯模型个数的策略，孙丽等在此基础上提出了新的算法。
其算法的基本思想是对于每帧，在图像所有像素的模型总个数固定的情况下，对于频繁变化的背景点，当未达到像素点自身的模型个数上限且不超过图像模型总个数的前提下，可以“借用”相对稳定的区域像素点的未用模型个数的名额，用个数不定的模型来描述该像素点可能的背景。根据模型的转化规则，通过删除模型、增加模型、替换模型来动态分配模型个数及模型的参数更新，并实现背景模型的生成，从而使得背景模型个数能够随着场景的变化动态调整。
在当前时刻，每个像素点都有自己的初始模型，这些模型根据一定的阈值条件，被划分成背景模型和候选背景模型。背景模型和候选背景模型都有自我更新并保持自身模型的状态。当候选背景模型满足一定的条件后，转化成背景模型，而背景模型和候选模型通过刪除模型的机制来达到终止模型状态。本文的背景建模算法在不增加模型总个数的前提下，通过动态删除模型、增加模型以及模型间的转化三种处理机制，分配不定个数的背景模型，并自适应更新参数。
实验表明，该算法能够较好的处理复杂动态场景中背景的频繁变化如树枝叶摇曳、水面波动和喷泉，并在构建背景过程中，一定程度上克服了前景运动目标的影响。与传统的运动目标检测算法相比，本文算法对动态变化背景的描述能力更强，处理速度更快，符合实际场景中运动目标检测的实时性和准确性要求[22]。
第三章 改进的运动目标检测算法 7 12 运动目标检测方法研究总结
第四章 总结
运动目标检测是计算机视觉中富有挑战性的课题之一，对其展开研究具有重要的应用价值和理论意义。本文首先总结研究了现存的三种经典的运动目标检测算法：光流法、帧差法和背景差分法，并对分析了它们的优缺点。光流法不需要预先知道有关场景信息，可以支持摄像机的运动，但是计算复杂度高、耗时长、抗噪性能差，目前没有较好的通用硬件支持。帧差法是将相邻的两帧图像对应像素点进行相减而得到运动目标，能够适应光照突变，运算速度快、算法简单，但是检测结果容易出现“空洞现象”和“双影现象”，它适用于对实时性要求高，对检测的目标信息要求不高的场景中。背景差分法是将当前图像帧和建立的背景图片相减来得到运动目标，该算法复杂度不高，可以满足系统对实时性的要求，背景模型的建立对该方法的实现会产生至关重要的作用然后。
然后介绍了几种改进的检测算法，改进的三帧差分法将改进的 Sobel 边缘检测算子引入到三帧差分法中，因为图像的边缘信息不容易受噪声和亮度突变的影响，所以将三帧差分法和改进的 Sobel 算子相结合弥补了三帧差分法不能将运动目标轮廓完整检测出来的缺点。然后对检测结果进行后期处理，达到改善空洞现象和去噪的目的。最后通过实验对比经典三帧差分法和改进的三帧差分法的检测效果，结果表明改进的三帧差分法的检测结果准确性更高。利用光流场获得粗略的运动区域，将光流值经过滤波，二值化和形态学处理，获得大概的运动目标区域。利用帧间差分法将相邻两帧图像中变化的区域提取出来，通过结合光流法和帧间差分法的结果，进一步将运动目标的提取锁定在一个更加准确的范围内。背景建模法对于每帧，在所有图像像素模型总个数固定的情况下，对于频繁变化的背景点，当未达到像素点自身的模型个数上限且不超过图像模型总个数的前提下，可以借用相对稳定的区域像素点的未用模型个数的名额，用个数不定的模型来描述该像素点可能的背景，从而实现背景模型的动态分配及更新。并基于像素的时域信息，用不包含该像素点在内的小邻域内所有像素点的背景模型与当前点进行匹配，判断其是否为前景点，以此消除动态背景干扰的影响。这些算法都将为今后的研究提供参考和依据。第四章 总结 11 14 运动目标检测方法研究总结
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第五篇：“目标检测”——基于目标的教学设计
浙江台州市黄岩区院桥镇镇北小学（３１８０２０）阮林萍目标检测基于目标的教学设计（以下简称目标检测），首先要明确教学目标，然后再确定检测的内容和方式，即教学评价，最后设计教学活动。目标检测的核心是关注教学目标，特征是教学评价先于教学设计。本文主要讨论三个话题：什么是目标检测？为什么提出目标检测？如何实施目标检测？
一、概念界定：什么是目标检测目标检测是基于目标的教学设计，它并非全新的教学理念，崔允漷教授的《基于课程标准的教学》为本课题研究提供了很好的理论支持和启发。基于课程课程标准的教学不是一种教学方法，而是一种理念。基于标准的教学需要教师在对标准深刻理解的基础上，把握对学生的总体期望，将标准转化为年级目标，再根据学生特点和教学情境具体化为每一堂课的教学目标。目标检测是将教学目标、教学评价和教学活动融为一体的教学设计思路。这种教学设计，第一步是明确课时
浙江台州市黄岩区院桥镇镇北小学（３１８０２０）阮林萍目标检测基于目标的教学设计（以下简称目标检测），首先要明确教学目标，然后再确定检测的内容和方式，即教学评价，最后设计教学活动。
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