This paper deals with research on detecting moving point target trajectory in image sequence. A novel method is presents for this purpose, which combines two 2-dimension Hough transforms to suppress noise points and to detect trajectory points in time order. The first Hough transform has an accumulators array using a restricted voting process and a set of straight lines are found in the image plane. A new T-L parameter space is proposed which is derived from these straight lines. In the second transform, collinear points are mapped into T-L space and it is easy to find the direction of motion. Experimental results show that our method can effectively extract moving point target trajectory accurately in a limited observing time especially scanning images from large numbers of noise points while search region is much larger than target movability. Key words : Moving point target (MPT) trajectory detection, dual-Hough transform (DHT), X-Y-T observation space, T-L parameter space
NTRODUCTIONIn long-range infrared detection and tracking application, target is close to point source, and motion trajectory becomes an important evidence for target detection and prediction for the absence of shape information. When search region is much larger than target movability and there are large number noise points with intensity over segmentation threshold, one Hough transform will give many false trajectories consist of noise points or real target trajectories mixed noise points. That will interfere with predicting trajectory in a limited observing time especially for scanning images.The Hough transform HT [1] is a powerful method for parameter extraction of any analytic pattern in images. By mapping features of an image space into a parameter space, the Hough transform converts a difficult global detection problem to a more easily solved local peak detection problem [2]. The main advantages of the Hough transform are its robustness to noise in the image and discontinuities in the pattern to be detected--both of which are frequently encountered in real-world images.The principal disadvantages of the standard Hough transform (SHT) are its demand for a tremendous amount of computing power and large storage. Both the storage and computation grow exponentially with the number of parameters. The SHT can be successfully adapted for detecting patterns with two parameters, e.g. straight lines, centers of circles with a fixed radius etc. However, it is not practical for direct application of the HT for a pattern with three of more parameters, because both the computer storage and computation grow exponentially with the number of parameters. To deal with this particular difficulty, Scholars have proposed many efficient implementations of the HT. One kind of these methods is the parameter space decomposition technique [3,4,5]. It decomposes the computation into separate stages, each stage passing results to the next, in this way, a high dimensional parameter problem is reduced to a series of lower dimensional problem. Another type of methods...