摘要：
Ochotona curzoniae is an endemic species and key species in the alpine meadow of the Tibetan Plateau and also it is a main kind of organism that destroys the grassland ecology of the plateau. In order to prevent the dangers of the ochotona curzoniae, we need to study the living habits of ochotona curzoniae and investigate the degree of harm of ochotona curzoniae, and then we can control the number of ochotona curzoniae through the effective preventive measures. With the development of sensing technology and image processing, we can provide an objective basis through intelligent monitoring system to control the damage of ochotona curzoniae. The object detection of ochotona curzoniae is a key technology in the intelligent monitoring equipment because it can provide the object contour feature for behavior analysis of ochotona curzoniae. The object detection of ochotona curzoniae is very difficult, because the ochotona curzoniae video possesses the characteristics of complex background, low contrast, the object color with intensity inhomogeneity, diversity and mutability. The traditional object detection method cannot extract the object contours accurately. This paper presents a fast object detection method based on space-time domain. Firstly, the centroid position of the object in the current frame image is determined by the background subtraction, and then the rough segmented image and the initial contour are obtained based on the centroid position. The rough segmented image is segmented by the improved Chan-Vese model, and then we can obtain the object contours. In view of the fact that the level set function needs to be initialized in the process of improved Chan-Vese model, and the initialized computation is enhanced with the increase of the image scale, the centroid of the object is taken as the center to intercept the image containing the object as the roughly segmented image. Then, the improved Chan-Vese model is used to segment the roughly segmented image, so as to reduce the time consumption of Chan-Vese model segmentation. In addition, as Chan-Vese model can't fully segment the image of object whose color is diverse and mutable, we use the improved Chan-Vese model to segment the roughly segmented image. The internal pixels of image evolution contours were processed by K-means clustering, and the clustering center point values were obtained. The internal fitting values of Chan-Vese model were constructed by the clustering center point values and the image mean filtered intensity information, thereby improving the adaptability of Chan-Vese model for complex object image segmentation.In addition, rectangular Dirac function was used to replace regularized Dirac function in the energy function of Chan-Vese model, and the calculation of level set evolution equation could be limited to the zero level set so as to avoid the influence of the image background disturbance on the segmentation result. In this paper, the video processing with 50 frames of images shows that the time consumption of this method is only 15.25 s, the average value of Dice similarity coefficient is 0.852 929, and the average value of Jaccard index is 0.744 57. In summary, the object detection method proposed in this paper can accurately extract the object contour and has a high real-time performance.%自然场景下的高原鼠兔序列图像对比度低,边缘较弱,目标包含多色彩且目标运动具有突变性.针对传统运动目标检测方法不能精确提取多色彩目标轮廓的问题,提出一种基于时空域联合信息的运动目标检测方法.首先,利用背景减法确定当前帧图像中目标的形心位置,得到粗分割图像及初始轮廓,然后用改进Chan-Vese(CV)模型对粗分割图像进行分割,改进 Chan-Vese 模型对多色彩目标图像适应性强,从而获得精确的目标轮廓.鉴于几何活动轮廓模型在图像分割过程中需不断初始化水平集函数,且初始化计算量随图像规模的增大而增多,该文在背景减法获得目标形心的基础上,以形心为中心,截取包含目标的图像块作为粗分割图像,然后利用改进 Chan-Vese 模型对粗分割图像精确分割,以减少分割耗时.该文对包含50帧图像的视频处理,试验结果显示:该文方法耗时仅为15.25 s,相似度指数平均为0.852929, Jaccard指数平均为0.74457.和背景减与CV模型相结合的运动目标检测方法相比,该文方法过分割率低,无冗余轮廓,且耗时短;和背景减与改进 CV 模型相结合的运动目标检测方法相比,该文实时性更高;该文所提出的目标检测方法可精确提取目标轮廓且实时性高.
