基于小波变换的 EMCCD微光图像融合算法

摘要

Because of different gain , the image content displayed by the electron multiplying charge coupled device (EMCCD) was different and the image had low contrast and narrow dynamic range .Meanwhile, the overall image was dark, fuzzy and whitish .An image fusion algorithm based on wavelet transform was put forward to apply into low-light-level images with different gain levels .Firstly, two groups of low-light-level images were acquired in the same scene with different gain level.Secondly, proper fusion rules were chosen based on low-light-level image’s characteristics after wavelet transform.Finally, the images were fused by wavelet transform , high quality fusion image and the performance data of fusion image , such as entropy , standard deviation , average gradient were obtained .Results show that the fusion algorithm based on wavelet transform can make the fusion image with both low and high brightness scenery and enlarge the image ’ s dynamic range and contrast .The image quality is effectively improved .%由于增益水平的不同，电子倍增电荷耦合器件图像所显现的图像内容不同，且图像动态范围极窄、对比度低、图像整体偏暗或模糊发白。为了提高微光图像动态范围及对比度，采用将不同增益水平的微光图像进行融合的算法，即先获取两组同场景但增益不同的微光图像，再对小波分解后的微光图像选择不同的融合规则，最后通过小波变换实现图像融合，得到了高质量的融合图像，并取得了融合图像的信息熵、标准差、平均梯度等性能指标数据。结果表明，该融合算法能使得融合后的图像同时包含低亮度景物和高亮度景物，达到了增大微光图像的动态范围及对比度的目的，有效改善了微光图像的质量。