Infrared image registration and high-resolution reconstruction using multiple translationally shifted aliased video frames
Infrared image registration and high-resolution reconstruction using multiple translationally shifted aliased video frames
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DOI：
10.1109/19.872908
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发表时间：
2000-10-01
影响因子：
5.6
通讯作者：
Yasuda, BJ
中科院分区：
文献类型：
--
作者：
Alam, MS;Bognar, JG;Yasuda, BJ
前视红外(FLIR)探测器阵列通常产生空间欠采样图像，因为不能使前视红外阵列足够密集以产生足够高的空间采样频率。多帧技术，如微扫描，是减少混叠和提高凝视成像系统产生的图像分辨率的有效手段。这些技术涉及交错一组在采集期间已经彼此移位的图像帧。前视红外系统安装在移动平台上，例如飞机，与平台相关的振动被用来产生位移。由于需要固定数量的图像帧，并且移位是随机的，因此获取的帧不会落在均匀间隔的网格上。此外，一些获取的帧可能具有几乎相似的移位，从而使得它们不能用于高分辨率图像重建。在本文中，我们利用基于梯度的配准算法来估计采集到的帧之间的移位，然后使用加权最近邻方法将这些帧放置到均匀的网格上，形成最终的高分辨率图像。当以小于探测器宽度一半的亚像素移动尝试微扫描时，探测器和成像系统的光学的模糊限制了图像分辨率的增加。我们将利用成像系统的调制传递函数(MTF)设计的维纳滤波器应用于高分辨率图像，从而解决了这一难题。仿真和实验结果验证了该方法的有效性。这里提出的技术比替代技术快得多，并且被发现特别适合实时应用。
Forward looking infrared (FLIR) detector arrays generally produce spatially undersampled images because the FLIR arrays cannot be made dense enough to yield a sufficiently high spatial sampling frequency. Multi-frame techniques, such as microscanning, are an effective means of reducing aliasing and increasing resolution in images produced by staring imaging systems. These techniques involve interlacing a set of image frames that have been shifted with respect to each other during acquisition. The FLIR system is mounted on a moving platform, such as an aircraft, and the vibrations associated with the platform are used to generate the shifts. Since a fixed number of image frames is required, and the shifts are random, the acquired frames will not fall on a uniformly spaced grid. Furthermore, some of the acquired frames may have almost similar shifts thus making them unusable for high-resolution image reconstruction. In this paper, we utilize a gradient-based registration algorithm to estimate the shifts between the acquired frames and then use a weighted nearest-neighbor approach for placing the frames onto a uniform grid to form a final high-resolution image. Blurring by the detector and optics of the imaging system limits the increase in image resolution when microscanning is attempted at sub-pixel movements of less than half the detector width. We resolve this difficulty by the application of the Wiener filter, designed using the modulation transfer function (MTF) of the imaging system, to the high-resolution image. Simulation and experimental results are presented to verify the effectiveness of the proposed technique. The techniques proposed herein are significantly faster than alternate techniques, and are found to be especially suitable for real-time applications.