共查询到19条相似文献,搜索用时 109 毫秒
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时域高通滤波非均匀性校正是一种典型的基于场景的红外焦平面阵列非均匀性校正算法,但其易产生"鬼影"现象,影响校正效果.本文在时域高通滤波校正算法的原理基础上,分析了其校正过程中"鬼影"现象产生的原因,即由于全部图像信息的叠加而导致静止场景被滤除且运动场景会在当前位置留下反转的图像,从而形成"鬼影".引入非局部均值滤波方法,提出了一种去"鬼影"的非局部均值滤波-时域高通滤波非均匀性校正方法.该方法首先采用非局部均值滤波将图像信息分离成高低频两部分(其中高频成分含有大部分噪音及非均匀性),并使用高频成分进行时域高通滤波算法中低通输出的递归运算,使得低通滤波后的图像含有较少的场景信息,从而可使校正输出图像含有较少的"鬼影"现象.采用两组真实红外序列图像进行验证,结果表明该算法不仅能获得较好的非均匀性校正效果,而且能较好地抑制时域高通滤波算法中的"鬼影"现象. 相似文献
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根据递推最小二乘和图像配准原理,提出了基于递推最小二乘的红外焦平面非均匀校正算法(简称ILS算法),有效降低算法的时间和空间复杂度,使噪音图像的校正处理能够实时完成.ILS算法具有噪音参量估计准确度高、收敛速度快和计算复杂度低等优点.给出了算法的推导并用仿真数据对算法的有效性进行验证. 相似文献
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基于递推最小二乘的红外焦平面非均匀校正算法 总被引:5,自引:4,他引:1
根据递推最小二乘和图像配准原理,提出了基于递推最小二乘的红外焦平面非均匀校正算法(简称ILS算法),有效降低算法的时间和空间复杂度,使噪音图像的校正处理能够实时完成.ILS算法具有噪音参量估计准确度高、收敛速度快和计算复杂度低等优点.给出了算法的推导并用仿真数据对算法的有效性进行验证. 相似文献
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基于非线性模型的卡尔曼滤波非均匀性校正算法 总被引:1,自引:0,他引:1
针对红外焦平面阵列探测单元响应的非线性对非均匀性校正的影响,利用探测器响应的非线性模型,对卡尔曼滤波非均匀性校正算法进行扩展和改进,以有效地克服响应非线性对校正精度的影响.该算法先对图像进行非线性压缩,转换为线性图像,再利用线性模型下的卡尔曼滤波算法实施非均匀校正,然后对其进行取指数操作,即得到原图非均匀校正后的图像.实验结果表明,该算法不仅继承了原算法利用场景信息来最优地更新校正参数的估计,解决了探测器偏置和增益漂移对校正影响,而且还在一定程度上解决了响应非线性对校正性能的影响,从而获得了较好的非均匀性校正效果. 相似文献
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提出了一种基于场景的红外图像非均匀性校正算法。该算法结合了两点定标校正算法和基于场景的改进的恒定统计算法,将两点校正算法的校正系数作为恒定统计算法的系数初值,并引入阈值进行运动状态检测,对运动场景和非运动场景分别进行系数更新。实验表明,该算法可以实现对红外图像非均匀性的校正,对于本文实验中的视频图像,在100帧时算法收敛,其收敛时间优于其他传统基于场景的非均匀性校正算法,并一定程度上抑制了"鬼影"现象。 相似文献
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对红外焦平面阵列成像系统而言,基于场景的非均匀校正技术是处理固定图案噪声的关键技术。现有的非均匀校正算法主要被收敛速度和鬼像问题所限制。提出一种新的基于恒定统计算法的自适应场景非均匀校正技术。利用红外图像序列的时域统计信息结合提出的α修正均值滤波来估计探测器的参数,通过减少样本的渐进方差估计,完成成像系统的非均匀性校正。通过模拟和真实的非均匀性图像对算法的性能进行评价。实验结果表明,在继承恒定统计算法快速收敛的同时,图像峰值信噪比较恒定校正法及常系数α校正算法分别有44.5%和32.9%的提升,图像鬼像问题有明显改善。 相似文献
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针对红外遥感图像非均匀性的定量评价问题,研究了基于场景的红外焦平面阵列响应非均匀性的定量评价方法。利用真实红外遥感图像序列量值分布的特点,针对小序列图像提出了基于序列排序和小波变换的标准图像构建算法;结合非均匀性评价指标,提出了利用构建标准图像的响应非均匀性对红外图像的非均匀性进行定量估计;分别利用黑体定标实验和统计方法对标准图像构建算法进行了验证,同时进行了不同校正算法的剩余非均匀性评价实验。结果表明,128frame序列构建得到的标准图像的非均匀性分别比同温黑体图像小0.92%,比统计标准图像大0.59%。该方法可用于定量估计红外遥感图像的非均匀性。 相似文献
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A fast scene-based nonuniformity correction algorithm is proposed for fixed-pattern noise removal in infrared focal plane array imagery. Based on minimization of L0 gradient of the estimated irradiance, the correction function is optimized through correction parameters estimation via iterative optimization strategy. When applied to different real IR data, the proposed method provides enhanced results with good visual effect, making a good balance between nonuniformity correction and details preservation. Comparing with other excellent approaches, this algorithm can accurately estimate the irradiance rapidly with fewer ghosting artifacts. 相似文献
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Chao Zuo Qian Chen Guohua Gu Xiubao Sui Jianle Ren 《Infrared Physics & Technology》2012,55(4):263-269
In this paper, an improved interframe registration based nonuniformity correction algorithm for focal plane arrays is proposed. The method simultaneously estimates detector parameters and carries out the nonuniformity correction by minimizing the mean square error between the two properly registered image frames. A new masked phase correlation algorithm is introduced to obtain reliable shift estimates in the presence of fixed pattern noise. The use of an outliers exclusion scheme, together with a variable step size strategy, could not only promote the correction precision considerably, but also eliminate ghosting artifacts effectively. The performance of the proposed algorithm is evaluated with clean infrared image sequences with simulated nonuniformity and real pattern noise. We also apply the method to a real-time imaging system to show how effective it is in reducing noise and the ghosting artifacts. 相似文献
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This paper proposes a new registration method for infrared images under conditions of fixed-pattern noise (FPN). Conventional registration techniques are susceptible to FPN and it is therefore very desirable to have a registration algorithm that is tolerant to FPN. For this purpose, we utilize the difference of the cross-power spectrum of two discrete shifted images to suppress the noise power spectrum while the shifts information is well preserved. In particular, we show that the phase of the cross-power spectrum difference is a periodic two-dimensional binary stripe signal with the exact shifts determined to subpixel accuracy by the number of periods of the phase difference along each frequency axis. Robust estimates of shifts can be obtained by transforming its discontinuities to Hough domain. Experimental results show that the proposed method exhibits robust and accurate registration performance even for the noisy images that could not be handled by conventional registration algorithms. We have also incorporated this technique to a registration-based nonuniformity correction (NUC) framework, indicating that our registration technique is able to estimate motion parameters reliably, leading to satisfactory NUC result. 相似文献
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红外探测器响应漂移特性会降低红外焦平面阵列(IRFPA)非均匀性校正的精度。针对该问题提出了一种基于场景的IRFPA非均匀性校正算法。该算法利用所获得的序列成像场景信息,采用一种基于快速自适应滤波器的最优化递归估计方法来获得非均匀性校正参数,并利用当前的成像信息来更新校正参数,以此降低探测器响应漂移特性对非均匀性校正的影响。算法仿真实验显示,对非线性参数为26.12%的同一图像,使用该算法、两点校正算法和卡尔曼滤波校正算法校正1 h后,可分别将非线性参数降至1.856%,3.122%和1.893%,说明该算法可获得稳定而较好的非均匀性校正效果。 相似文献
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A three-step nonuniformity correction algorithm based on the photoelectrical response models of intensified charge-coupled device (ICCD) for a highly dynamic ICCD star sensor is proposed in the current paper. The influence factors of nonuniformity correction precision are analyzed based on the photoelectrical imaging theory. The photoelectrical response models of ICCD are obtained using the experimental method, and the nonuniformity correction is implemented in three steps based on the photoelectrical response models. The nonuniformity correction results in constant-radiance images and sky images of the highly dynamic star sensor show that the proposed algorithm has satisfactory correction precision, and the accuracy of the highly dynamic star sensor can be enhanced effectively when sky images are processed using the three-step nonuniformity correction algorithm. 相似文献
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针对两点温度定标算法在应用过程中曝露的问题,提出了基于变积分时间的红外焦平面非均匀性校正算法.该算法先对图像进行非线性压缩,转换为线性图像,再利用红外焦平面阵列探测元的响应特性与积分时间之间的关系,采用改变积分时间的方法拟合红外焦平面探测器的平均响应特性曲线,进行两点校正,然后对结果进行取指数操作,即得到原图非均匀校正后的图像.分别利用两点温度定标法和变积分法对航拍红外图像进行校正效果验证,同时进行了不同校正算法的非均匀性适应性评价实验.实验结果表明新算法计算量小,校正准确度高,反应速度快,并在一定程度上解决了大动态范围下响应非线性对校正性能的影响,具有很好的工程应用价值. 相似文献
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This paper puts forward a new scene based nonuniformity correction algorithm for IRFPA. This method adopts phase-correlation method for motion estimation and takes the sum of mean-square errors of the pixel brightness between several adjacent frames as the cost function when the brightness constancy assumption between two adjacent frames is satisfied. Nonuniformity correction parameters could be estimated by minimizing such cost function. In order to reduce calculation quantity, we can divide these images into several subblocks, and solve for the optimum solution of the cost function respectively in each subblock. From the analysis, it is shown that the optimum solution is of global uniqueness when all the elements in subblocks could satisfy the ergodicity condition. Then the estimated value of nonuniformity correction parameters could be deduced by minimizing the cost functions. The nonuniformity correction experiments for both infrared image sequence with simulated nonuniformity and infrared imagery with real nonuniformity show that the proposed algorithm could achieve a great correction effect by only analyzing a small number of frames. 相似文献