Papers by Author: Zhi Jing Yu

Abstract: Runway debris visual automatic detection system is one of key measures that ensure efficient and safe airport operation. It can automatically recognize runway debris with visual detection methods, and determine the orientation of scanning system with attitude estimation method, then realize automatically detect debris. In this paper, the recognizing method of fixed feature navigation lights that are used to calculate system orientation are researched on. Runway area and background are detached by recognizing runway lines. Navigation lights are recognized and matched by the method of image matching. Experimental result show, runway can be separated and recognized from complex environment, and navigational lights can be matched quickly in the algorithm. The reliable fixed feature is supplied for followed determining scanning system orientation and located debris.

Abstract: This paper presents the modeling of stereo vision measurement for solving the optimal spatial point under non-ideal circumstances, and then analyzes the error of stereo vision measurement system from the imaging feature location and camera internal parameters and external parameters, such as the focal length, the baseline distance, which plays a important role in optimization of system architecture and layout of measurement system.

Abstract: The terrain in the virtual realistic environment will determine the scene generation level of realism. It has been a hot topic in computer graphics. In this paper, the analysis of the current generation of multi-terrain texture mapping method is carried out firstly. At the same time, the advantage and disadvantage of the method is pointed out. A new means is put forward. It is that while the gray images are proposed to provide terrain height field constraints, the image intensity information generated by the random noise is used as constraints to determine the random distribution information on different texture of terrain. At last, a realistic terrain using OpenGL Library Standard in Win32 console application is developed which is close to the natural environment with a high application value.

Abstract: In order to detect the ice on aircraft wings, a method based on near infrared image processing is proposed. According to the variety of near-infrared reflectivity, four images of one object are obtained under different detection wavelengths. Water and ice can be distinguished by the different variation trends of near infrared images. In this paper, 1.10μm, 1.16μm, 1.26μm and 1.28μm are selected to be the detection wavelengths. The images of Carbon Fiber Composite material aircraft wings partially covered by water or ice are obtained and analyzed. Parameter D can reflect the variation trend of relative near-infrared reflectivity, so that Parameter D also can be the distinguish basis. The results of the experiment show that the method proposed in this paper is available for ice detection.

Abstract: In order to improve the accuracy of near infrared multispectral ice detection on aircraft wings, we present an improved unit detection algorithm to reduce the noise influenced by the ice detection system itself. The improved algorithm, first select matrices being 3*3 as a detection unit, then calculate the contrast value of the five pixel points in the cross region of the unit, and finally count the number of pixel points, whose contrast value are larger than the threshold value of ice on the surface. The experimental results show that the unit detection method has high accuracy and efficiency compared with conventional point-by-point method.

Abstract: With the aim to remove the unwanted feature points, template matching algorithm which includes pixel-coherence and fixed structure is proposed in this paper. Corner detection algorithm can extract image feature points with the flexibility for illumination variation and affine transformation. This paper gets the special points of plane image by corner detection algorithm and proposes the problem of existing more useless point. Then, template matching algorithm is used to solve the issue and collects the best match points. Finally, the paper compares the template image and the matched image. The experimental results prove that the feature points by template matching algorithm have excellent accurate characteristic for the illumination, transfer and the rotation transform, and they are highly satisfactory.

Abstract: A method of decoding ring marks and EO device was presented in this paper. Also the GSI coded targets had been analyzed and a new type of optical probe can be recognized in use of affine transformation and the cross ratio. Experimental results show that the EO device and optical probe are to be identified correctly and efficiently.

Abstract: The airport runway frictional coefficient is one of the most important factors which affects the safety of airplane's landings and take-offs under the rain or snow weather. In this paper, each kind of factor which affects the precision of frictional coefficient measurement under the bad condition such as snow and ice covered, rubber pollution and wet runway have been analyzed, and then establish the model of frictional coefficient measurement. A new strategy which uses variable gain recursion least square algorithm has been used to eliminate the error caused by the rugged runway in the high speed measurement process, so as to assure system anti-jamming ability and fast track capacity. Use the vertical pressure pertinence analysis to eliminate the errors caused by the runway surfacing joint.

Abstract: An optical imaging based fully automatic stereo vision system for aircraft assembly online measurement is presented and analyzed. In this system, the relative position of the two cameras can easily calibrated by imaging an optical reference bar in different locations and orientations throughout the measurement space according to epipolar constraint and the certified distance of the features on the reference bar. For measurement, the system takes infrared LEDs which attached at measured object as imaging targets, and makes use of the measurement results of these feature points space coordinates to calculate the related positions of the assembly aircraft parts. Furthermore, using automatic infrared LED light intensity and CCD cameras exposure time improve the calibration and measurement accuracy. The effectiveness of the proposed system has been test by experiments.

Abstract: A fully automatic and rather flexible mobile vision 3D coordinate online measurement system is presented and analyzed. The system is composed of a high resolution CCD camera, retro-reflective feature points, and an external orientation device. The feature points, which fixed on the measured object and external orientation device, are imaged by camera in several locations and orientations. The initial external locations and orientations of the camera relative to the fixed external orientation device are determined by pose estimate algorithm, and the feature points coordinates, i.e. measured points coordinates on the object, are calculated by bundle adjustment algorithm based on collinear constraint. To improve the measurement accuracy, the locations of the imaging feature points are determined by bilinear centroid sub-pixel algorithm. The effectiveness of the proposed system has been tested by experiments.