Real-time object tracking for moving target auto-focus in digital camera
Real-time object tracking for moving target auto-focus in digital camera
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DOI：
10.1117/12.2075795
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发表时间：
2015-02
期刊：
影响因子：
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通讯作者：
Haike Guan;Norikatsu Niinami;Tong Liu
中科院分区：
文献类型：
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作者：
Haike Guan;Norikatsu Niinami;Tong Liu
准确地对焦移动物体对于在数码相机中成功拍摄目标照片来说是困难且重要的。由于物体经常随机移动且形状频繁变化，因此需要实时估计目标的位置和距离，以便精确地聚焦在物体上。我们提出了一种实时目标跟踪的新方法，用于对数码相机中的移动目标进行自动对焦。摄像机中的视频流用于运动目标跟踪。粒子滤波器用于处理目标物体随机运动和形状变化的问题。颜色和边缘特征用作对象状态的测量。开发并行处理算法，在数码相机的硬件环境下轻松实现实时粒子滤波目标跟踪。还提出了运动预测算法，以消除由于拍照时跟踪结果与目标物体真实位置之间的差异而导致的聚焦误差。数码相机的仿真和实验结果证明了该方法的有效性。我们在数码相机中嵌入了实时对象跟踪算法。通过对视频流中的目标跟踪，准确获取运动目标的位置和距离。采用SIMD处理器强制并行实时处理。 CPU频率仅为162MHz的数码相机可以实现每帧不到60ms的处理时间。
Focusing at a moving object accurately is difficult and important to take photo of the target successfully in a digital camera. Because the object often moves randomly and changes its shape frequently, position and distance of the target should be estimated at real-time so as to focus at the objet precisely. We propose a new method of real-time object tracking to do auto-focus for moving target in digital camera. Video stream in the camera is used for the moving target tracking. Particle filter is used to deal with problem of the target object’s random movement and shape change. Color and edge features are used as measurement of the object’s states. Parallel processing algorithm is developed to realize real-time particle filter object tracking easily in hardware environment of the digital camera. Movement prediction algorithm is also proposed to remove focus error caused by difference between tracking result and target object’s real position when the photo is taken. Simulation and experiment results in digital camera demonstrate effectiveness of the proposed method. We embedded real-time object tracking algorithm in the digital camera. Position and distance of the moving target is obtained accurately by object tracking from the video stream. SIMD processor is applied to enforce parallel real-time processing. Processing time less than 60ms for each frame is obtained in the digital camera with its CPU of only 162MHz.