Computer-Vision计算机视觉英文ppt.ppt

1、Computer Vision,Computer vision research,At the end of the 1950s, computers had became an important tool for human beings to realize the human intelligence and human perception, with the help of computer, For the first time, human beings can realize the extension of mental and perceptual ability as

2、well as the extension of physical strength with the aid of the machine. the simulation of human visual perception leads to the generation of computer vision. Specifically, computer vision will achieve three basic purpose. 1The first purpose is to calculate the distance from the observation point to

3、the object according to one or more 2D images;,2The second purpose is to calculate the Motion parameters from the observation point to the object according to one or more 2D images; 3The third purpose is to calculate the physical characteristics from the observation point to the object according to

4、one or more 2D images; There are two ultimate goal that computer vision will realize, they can be simply described as follow: one is to realize the understanding of the world,in other words, it can realize some functions of the human visual system; the other is to rebuild the three dimensional objec

5、t according to the two-dimensional projection images .,History of computer vision,1950s: in this period , statistical pattern recognition is most applied in computer vision , it mainly focuse on the analysis and identification of two-dimensional image,such as: optical character recognition, the surf

6、ace of the workpiece, the analysis and interpretation of the aerial image. 1960s: Roberts (1965) use a computer program to extracte the three-dimensional structure of a polyhedron from the digital images .he also describe the shape and the spatial relationship of objects. Roberts created a new situa

7、tion for the research of computer vision . his purpose of research began to become the understanding the three-dimensional scene. the creative research for the blocks world give people great inspiration. many people believe that once the three-dimensional world made up of the white building block to

8、y could be understandable.s it also can be extended to understand more complex 3D scene.,the research scope of the block world is extensive. it includes the feature extraction of edge and corner,the geometric factor analysis of line and plane.It also build a variety of data structures and inference

9、rules. In the middle of 70s,artificial intelligence (AI) laboratory of Massachusetts Institute of Technology (MIT) officially opened the machine vision course. At the same time, AI MIT laboratory has attracted many famous scholars from the world to participate in the research of machine vision,which

10、 included the theory of machine vision , algorithm and design of system . Professor David Marr in 1973 was invited to lead a research team which is consisted of doctoral students in the MIT AI Lab .in 1977,David Marr put forward a new computer vision theory which is different from the past theory wh

11、ich is build on the analysis method of blocks world.in the 1980s,his theory had become a very important theoretical framework in the field of machine vision .,Changes in the name of a publication can reflect the progress of computer vision: 1972, CGIP (computer graphics and image processing) publica

12、tion; In 1983, its name is CVGIP (computer vision, graphics and image processing); In 1991, the publication is divided into two versions, which are CVGIP-GMIP (graphics model and image processing) and CVGIP-IU (image understanding);,In 1995, the publication become two magazine . the former named GMI

13、P (graphics model and image processing), the latter named CVIU (computer vision and image understanding). The upsurge of research on computer vision began in 1980s, and in the middle of 80s, the computer vision has developed rapidly, new concepts, new methods and new theories have emerged. So far, c

14、omputer vision is still a very active research area.,Advances in computer vision research,After nearly 50 years, research in computer vision has made considerable achievements. This makes the field to become the most active part of the AI research in the past 40 years. Its mainstream research is div

15、ided into three stages: Stage 1: Research on the visual basic method ,which take the model world as the main object; Stage 2: Research on visual model ,which is based on the computational theory; Stage 3: Research on the computer vision method with the goal of application;,stage 1,In 1965, Roberts u

16、se a computer program to extracte the three-dimensional structure of a polyhedron from the digital images .he also describe the shape and the spatial relationship of objects. In the work of Roberts, the relationship between 3D objects and 2D imaging is introduced, and some simple methods of feature

17、extraction are introduced. Later, people began to makes a deep study of block world and establish a variety of data structures and inference rules.The scope of the study is abroad,which include the feature extraction of edge and corner , geometric elements analysis of line and flat surface, surface.

18、,The study of block world reflects some of the characteristics of early visual research, that is starting from a simplified world. The work in this period has played an important role in the development of computer vision, but it is difficult to work for a slightly complex scene. Research on this st

19、age is based on the analysis of three dimensional spatial relations , moerover , analysis of three-dimensional relationship is only rely on simple constraint relations.,stage 2,Beginning in 1970s, the study of computer vision begin to come into a more rational stage. 1people begin to study the imagi

20、ng methods from the point of view of physiology, optics and projective geometry. 2Reasearch is mainly concentrated in the recovery of the various intrinsic characteristics, including the recovery of three-dimensional shape, motion, light source, etc. In this stage, some researchers, represented by M

21、arr, put forward a general visual processing model,.,stage3,After entering the 1990s,with the reflection on the research of artificial intelligence ,people are starting to think about whether the past mehtods is correct,whether the theory has practical significance in the area of computer vision. re

22、search on computer vision was transferred from the simple theoretical framework to the combination of a variety of applications. Some of the important characteristics of biological vision in the past have not been paid enough attention.Therefore, in the early 90s, some scientist has put forward new

23、methods and new ideas of active vision and qualitative vision. By using active geometric method , some complex computers can be simplified.,The application of computer vision,Industrial vision: people get the internal image of the object by X - ray or ultrasonic detection to achieve the surface defe

24、ct inspection, internal non - destructive testing, etc.; Through cameras and related visual information processing system, people could choose the different transmission belt accord to the different objects ，then separate the object from the transmission belt and identify and locate it.,：Human compu

25、ter interaction: people can let the computer use the demands of the human gestures , lip movements (lipreading), physical exercise (gait), facial expression to understand peoples desire , which is in line with the habit of human interaction, it also can increase the convenience. Such as face recogni

26、tion, intelligent agents, etc.,人,Visual navigation: People can use two or more cameras to get a set of images to recover 3D scene information, and use these 3D scene information to recognize target, to identify the road, identify obstacles.,Stereo images acquired by a stereo vision system can be use

27、d to reconstruct 3D scene information.,Visual navigation： The combination of stereoscopic images and motion information can be a scene graph to meet the specific task. Such as cruise missile guidance, unmanned aircraft flying, automatic moving vehicles, mobile robots, etc., not only to avoid the ris

28、k of human involvement, but also to improve the accuracy and speed.,Courage Rover,Rocky 7 Mars rover,Security identification, monitoring and tracking:： Parking area monitoring, vehicle identification. Machine can identify a specific person accord to the features of the face, the eye ground, the fing

29、erprint ; At present, people are studying a kind of facial motion parameters in order to analyze the human expression and inner activities by the extraction and description of the parameters.,Medical image analysis： There are two aspect in the application of computer vision in medical image diagnosi

30、s : First, the image enhancement, labeling, dyeing and other processing can help doctors to diagnose the disease, and to assist doctors to measure and compare the area of interest; second,it can use the expert knowledge system to analyse and explanation an image (or a series of images in a period of

31、 time) .,Contents of computer vision research,1）(input device) including imaging equipment and digital equipment. Imaging device is a device which can detect the scene or object by the optical camera or X rays, and get the 2D or 3D digital image of the scene or object. 2）(low level) Mainly to deal w

32、ith the input image. This process uses a large number of image processing techniques and algorithms, such as image filtering, image enhancement, edge detection, texture detection, motion detection, in order to extract the basic features of the scene.,3）（middle level） The main task is to restore the

33、depth of the scene, the direction of contact normal , contour and other 2.5 dimensional information of the relevant scene, the method to achieve it include stereo vision、rangefinder. 4）（high level） the main task has three aspect,one is to reconstruct the complete 3D graph ,the second is to build the

34、 3D description of object ,the third is to recognize and determine the position and orientation of the object.these process is based on the original input image, the basic characteristics of the image.,The relationship between computer vision and other subjects,1）(image processing) Image processing

35、is usually the transformation of an image into another image; The computer vision system takes the image as the input signal and generates another form of output signal. Image processing plays a great role in the early stage of machine vision system. 2） (computer graphics) It use geometric primitive

36、s (such as lines, circles) to generate the image, which belongs to the image synthesis; computer vision is just to solve the opposite problem, that is to estimate the geometric primitives and other features from the image, which belong to the image analysis. Visualization and virtual reality are closely related to the two fiel