利用地基观测相机拍摄的以深空为背景的星图受星空复杂背景的影响,往往具有较高的噪声水平。同时由于星图主要由恒星、空间目标和星空背景噪声组成,且成点状分布,星图目标和噪声呈现较大的相似性,传统的图像去噪算法并不适用于星图。为...利用地基观测相机拍摄的以深空为背景的星图受星空复杂背景的影响,往往具有较高的噪声水平。同时由于星图主要由恒星、空间目标和星空背景噪声组成,且成点状分布,星图目标和噪声呈现较大的相似性,传统的图像去噪算法并不适用于星图。为此,该文提出一种基于能量函数的极值中值滤波去噪算法,该算法在去除星图椒盐噪声的同时能够较好地保持图像目标信息。该方法针对疑似噪声点采用二次检测的方式,并且结合改进的自适应中值滤波和能量函数模型进行灰度值恢复。该文分别使用仿真试验和真实星图处理试验对该方法进行验证,在客观评价中,图像峰值信噪比PSNR(Peak Signal to Noise Ratio)最高可提高3倍多,均方误差MSE(Mean Squared Error)减小为加噪图像的3.16×10^(-5)。试验结果表明,该方法可有效地降低传统方法的噪声误检问题,同时提高噪声图像的恢复精度,非常适合星图噪声的去除。展开更多
传统的基于局部统计的实时增强算法不能解决噪声引入的固有缺点,抗噪性能差导致其应用效果不理想。针对这一缺点,提出了一种基于超限邻域法的改进的实时图像局部增强算法。和传统的基于局部统计的增强算法相比,算法较大地提高了其抗噪性...传统的基于局部统计的实时增强算法不能解决噪声引入的固有缺点,抗噪性能差导致其应用效果不理想。针对这一缺点,提出了一种基于超限邻域法的改进的实时图像局部增强算法。和传统的基于局部统计的增强算法相比,算法较大地提高了其抗噪性能,且需要额外计算的邻域均值在原有算法中已计算过,实际增加的计算量很小。增强后,边界不会出现明显轮廓,保证了视觉效果。仿真实验结果表明,改进算法的抗噪声性能得到提高,峰值性噪比提高接近4 d B。硬件平台测试后,每秒帧数达到了约50帧,能满足实时应用要求。展开更多
An approach to measure a high-dynamic two-dimensional(2 D) temperature field using a high-speed quadriwave lateral shearing interferometer(QWLSI) is proposed. The detailed theoretical derivation to express the wavefro...An approach to measure a high-dynamic two-dimensional(2 D) temperature field using a high-speed quadriwave lateral shearing interferometer(QWLSI) is proposed. The detailed theoretical derivation to express the wavefront reconstruct principle of the proposed method is presented. The comparison experiment with thermocouples shows that the temperature field measurement using QWLSI has a precision of ±0.5 °C. An experiment for measuring the highdynamic temperature field generated by an electrical heater is carried out. A 200 frame rate temperature field video with 512 × 512 resolution is obtained finally. Experimental results show that the temperature field measurement system using a QWLSI has the advantage of high sensitivity and high resolution.展开更多
文摘利用地基观测相机拍摄的以深空为背景的星图受星空复杂背景的影响,往往具有较高的噪声水平。同时由于星图主要由恒星、空间目标和星空背景噪声组成,且成点状分布,星图目标和噪声呈现较大的相似性,传统的图像去噪算法并不适用于星图。为此,该文提出一种基于能量函数的极值中值滤波去噪算法,该算法在去除星图椒盐噪声的同时能够较好地保持图像目标信息。该方法针对疑似噪声点采用二次检测的方式,并且结合改进的自适应中值滤波和能量函数模型进行灰度值恢复。该文分别使用仿真试验和真实星图处理试验对该方法进行验证,在客观评价中,图像峰值信噪比PSNR(Peak Signal to Noise Ratio)最高可提高3倍多,均方误差MSE(Mean Squared Error)减小为加噪图像的3.16×10^(-5)。试验结果表明,该方法可有效地降低传统方法的噪声误检问题,同时提高噪声图像的恢复精度,非常适合星图噪声的去除。
文摘传统的基于局部统计的实时增强算法不能解决噪声引入的固有缺点,抗噪性能差导致其应用效果不理想。针对这一缺点,提出了一种基于超限邻域法的改进的实时图像局部增强算法。和传统的基于局部统计的增强算法相比,算法较大地提高了其抗噪性能,且需要额外计算的邻域均值在原有算法中已计算过,实际增加的计算量很小。增强后,边界不会出现明显轮廓,保证了视觉效果。仿真实验结果表明,改进算法的抗噪声性能得到提高,峰值性噪比提高接近4 d B。硬件平台测试后,每秒帧数达到了约50帧,能满足实时应用要求。
基金supported by the National Natural Science Foundation of China(No.11603024)
文摘An approach to measure a high-dynamic two-dimensional(2 D) temperature field using a high-speed quadriwave lateral shearing interferometer(QWLSI) is proposed. The detailed theoretical derivation to express the wavefront reconstruct principle of the proposed method is presented. The comparison experiment with thermocouples shows that the temperature field measurement using QWLSI has a precision of ±0.5 °C. An experiment for measuring the highdynamic temperature field generated by an electrical heater is carried out. A 200 frame rate temperature field video with 512 × 512 resolution is obtained finally. Experimental results show that the temperature field measurement system using a QWLSI has the advantage of high sensitivity and high resolution.
