Application Of Analog Stereovision Into Space Orientation System

Photogrammetry has a long history. Tracing back to the middle 19th century, the beginning of it is analogous photogrammetry. Through the analytical photogrammetry, it is developing to the digital photogrammetry. Currently it incorporates with machine vision, a lot of theories and technology descended from it have played a more and more important role in our daily life. The research of digital photogrammetry has become the most sparkling field in natural science.Stereovision, an active brunch of robotic technology, is one important attribute of intelligent robot. Binocular stereovision can be defined as the process of tri-dimensional reconstruction through the abstraction, identification, matching and interpretation of twain images gathered from identical objective, mostly include: video frequency trapping, camera calibration, image preprocessing, feature extraction stereo matching and tri-dimensional reconstruction as well.This paper simulates the stereo visual principle, making use of double area CCD to set up a kind of space orientation system; and completes the foundation of Math-modeling. The system adopts gravity centering method, carrying out the precise orientation of laser blot, so that the precision of orientation attains 2%. Through measuring different rectangles, ellipses and triangles, the shapes of different blots have little to do with the precision; thus a good stability is achieved.Objects'precise dimension measure is an useful issue which is being used widely and has great active value. Computer-vision method for Object-dimension precise measure has been well utilized by its kinds of merits such as no-touch, high precision, easy process by computer, simple connection with control system etc. Object's three-dimensionreconstruction can be broadly used by kinds of fields such as robot navigation, vision surveillance, producing for buildings, producing for model, on-line product inspection etc. In resent years, it is also well used by computer-based virtual reality, Image Based Rendering, three-dimension animation etc. It can be realized by lots of methods, which can be distinguished into two kinds of methods (touch methods and no-touch methods). Among no-touch methods, the optical method is very popular. The main feature of optical no-touch method is that the surface of object is not touched during the measure by optical method. What's more, the optical no-touch method has the merits of high speed, good automatization and the wide-measured soft or hard objects with complicated surfaces. In recent years, the optical no-touch method of structure light has been widely attached importance to by its merits of no touch, easy operation and high precision etc. According to the existent theories, we build up objects'dimension measure and three-dimension reconstruction system respectively by one-camera vision and two- camera vision. These two systems are both realized by line structure-light active vision. The camera-calibration method is supported by random-plane method which is created and developed in recent a few years. The camera video data is collected by the video capture technique based on Directshow.The line structure-light vision system, Directshow technique and the random-plane calibration method are separately described in the following content.(i) line structure-light active vision systemFrom the aspect of structure light's form and figure, structure light can be distinguished by dot structure light, line structure light, circle structure light, multiple-line structure light and multicolor structure light etc. This paper's one-camera and two-camera systems are all developed by line structure-light vision system. The main operation steps for line structure-light ,laser-triangle method are that:①object is lighted by line structure light;②the images for the lighted object at different object's part are collected by camera and computer;③processing the images, reconstruct the object's three-dimension figure, analyzing the reconstruction figure. The main principle for line structure-light triangle method is that:①there is a triangle among object, projective point and observation point;②when the line-light stripe is projected onto the surface of object, the stripe will be curved by the scraggly surface of object. Because the curved stripe is made by the projective line stripe and the surface shape of object, this stripe must contain object's three-dimension information. The object's three-dimension figure can be deduced from the stripes'shape by building up a correct model for the relationship between curved stripe and object's surface shape.(ii) As for two-camera and line structure-light system, each camera has better capture at least ten pictures of random-laid calibration plane in order to resolve the calibration of inner parameters for each camera. Then, the calibration plane should be laid in public view field of both two cameras ,and the picture of plane should be captured by each camera in order to resolve the calibration of outer parameters for each camera.This calibration method use a calibration plane , but the plane's space position doesn't need to be measured by operator. The dots positions in plane is the only thing that need to be known.(iii) Directshow video capture techniqueIt is a video capture technique that has no relationship with hardware (such as video capture card).It dismisses the strong conjunction between the program makers and hardware manufactures. It doesn't need the support of further-development program package of video's hardware. So the program made by Directshow is more transplantable and can be used by all kinds of video capture cards or other kinds of video devices.According to this paper's detailed content, the line structure-light system for one camera and two camera are introduced separately.Three dimension reconstruction system using two cameras This paper introduced line structure-light system with two cameras. The main principles for rotated platform and line move platform were separately described. The main operation steps are: (i) calibrating the two cameras by random plane method;(ii) capturing object's pictures;(iii) After processing the pictures and matching feature points by the polar-line equation, the correspondence points can be matched.(iv)According the feature of rotated platform (or line move platform), object's dimension measure and three-dimension reconstruction can be done. Finally, line structure-light calibration and correspondence points'match were elementarily researched according to the experimental condition.