In order to enhance the speed and accuracy of ellipse detection, an ellipse detection algorithm based on edge classification is proposed. Too many edge points are removed by making edge into point in serialized form and the distance constraint between the edge points. It achieves effective classification by the criteria of the angle between the edge points. And it makes the probability of randomly selecting the edge points falling on the same ellipse greatly increased. Ellipse fitting accuracy is significantly improved by the optimization of the RED algorithm. It uses Euclidean distance to measure the distance from the edge point to the elliptical boundary. Experimental results show that: it can detect ellipse well in case of edge with interference or edges blocking each other. It has higher detecting precision and less time consuming than the RED algorithm.
Camera calibration is the first step of computer vision and one of the most active research fields nowadays. In order to improve the measurement precision, the internal parameters of the camera should be accurately calibrated. So one high-accuracy camera calibration algorithm is proposed based on the images of planar targets or tridimensional targets. By using the algorithm, the internal parameters of the camera are calibrated based on the existing planar target at the vision-based navigation experiment. The experimental results show that the accuracy of the proposed algorithm is obviously improved compared with the conventional linear algorithm, Tsai general algorithm, and Zhang Zhengyou calibration algorithm. The algorithm proposed by the article can satisfy the need of computer vision and provide reference for precise measurement of the relative position and attitude.
It is an important measure to observe target by using laser sensor in the field of target detection. Exact and reliable dynamic laser scatter characteristics of observing target, can not only be used for the design and development of laser sensor as well as the research of algorithm for target capture, recognition and tracking, but also can offer reference bases for the test flow programming. A set of simulation, measurement system for the dynamic laser scatter characteristics of observing target is introduced in this paper. The simulation problem of dynamic laser scatter characteristics of observing target is solved, under the circumstance of laboratory with different azimuth angle and pitch angle of observation. The dynamic laser scatter characteristics of observing target can be obtained directly by such system, the test data can be used for the verification of the analyzing model for the laser scatter characteristics of observing target, and can also offer basis for the development of laser detecting sensor.
Proc. SPIE. 9521, Selected Papers from Conferences of the Photoelectronic Technology Committee of the Chinese Society of Astronautics 2014, Part I
KEYWORDS: Target detection, Signal to noise ratio, Computer programming, Aerospace engineering, Surveillance systems, Image processing, Digital breast tomosynthesis, Computer simulations, Sensors, Detector development
With the development of Space Technology, the demand to Space Surveillance System is more urgent than before. The paper studies the dim and small target of long range. Firstly, it describes the research status of dim and small target abroad and the two detection principle of DBT and TBD. Secondly, it focuses on the higher-order correlation method, dynamic programming method and projection transformation method of TBD. Finally, it studies the image sequence simulation of different signal to noise ratio (SNR) with the real-time data from the aircraft in orbit. The image sequence is used to experimental verification. The test results show the dim and small target detection capability and applicable occasion of different methods. At the same time, it provides a new idea to the development of long-distance optical detector.
In order to make the visible image of target indicating its active state as real as possible, a kind of method for space target imaging simulation based on target visible scatter characteristics is proposed in this paper. The online real-time imaging simulation with high fidelity is implemented, which provides a good foundation for the researches of space-based target detection, recognition and tracking techniques.
Exact and reliable dynamic visible scatter characteristics of space target, can not only be used for the design and development of visible sensor as well as the research of algorithm for target capture, recognition and tracking, but also can offer reference bases for the flow programming of space test. A set of simulation measurement system for the dynamic visible scatter characteristics of space target is introduced in this paper. The simulation problem of dynamic visible scatter characteristics of space target is solved, under the circumstance of laboratory with different azimuth angle and pitch angle of solar illumination as well as different azimuth angle and pitch angle of observation. The dynamic visible scatter characteristics of space target can be obtained directly by such system, and the test data can be used for the verification of the analyzing model for the visible scatter characteristics of space target.
In many imaging systems, the detector array is not sufficiently dense to adequately sample the scene with the desired
field of view. In order to enhance the existed image resolution, several approaches to solve this problem have been
investigated previously, such as maximum a posteriori probability (MAP), projection onto convex sets(POCS) etc. Those
algorithms enhance reconstruct high resolution with reduced aliasing, from a sequence of undersampled frames. But
whether POCS, or MAP estimator in space domain, image pixels are rearranged by using lexicographic ordering as a
large matrix in procession. These methods have to solve a large ill-condition equation group, which leads to a big burden
of computation and storage, complexity of algorithm. So they are rarely used in practical application.
In order to solve these problems, a novel reconstruction high resolution(HR) image algorithm based on the standard
displacements of low resolution(LR) images is proposed. Moreover, a set of recursive updating algorithm models is
presented. The results of simulating experiments show that the resolution, the details as well as the definition of the high
resolution image given by using our method are greatly enhanced. At the same time, the running speed of our method is
greatly faster than other super-resolution methods.
Autonomous service on orbit is a new developing trend of space service, in order to realize on orbit servicing, the
problem of autonomous relative navigation needs to be solved. On the foundation of several typical schemes used by
American, Russian as well as ESA etc., the main conception of our autonomous video navigation system is determined.
The beacon system is composed of five beacon lamps, and has four invariant features relative to transformations of
rotation, translation and scale. Two sets of double camera systems constituted of three fixed lens cameras with short
focus are applied to the longer distance and the shorter distance respectively. Three kinds of measures are put forward to
suppress the interference of miscellaneous lights. Then, the study and simulation of beacon recognition as well as the
determination of relative positions and attitudes are expounded in this paper, the algorithm flow chart and corresponding
simulation results are given. A kind of spiral capturing algorithm is used to increase the capturing efficiency, and the
beacon recognition algorithm is designed according to the invariant features of beacon system to increase the recognition
capability. In the determination of relative positions and attitudes, monocular algorithm and binocular algorithm are
combined to ensure the reliability. Simulation results have verified the feasibility of the design of autonomous video
navigation sensor and the autonomous video navigation techniques.