一种基于双通道CMOS相机的低照度动态场景HDR融合方法

A Dynamic Scene HDR Fusion Method Based on Dual-channel Low-light-level CMOS Camera

高动态范围成像技术能够全面有效反映场景信息,有利于在高动态范围场景下获得高质量的成像。但当前常用的基于单台相机的多次曝光融合方法在动态场景下易出现“鬼影”问题,基于多个传感器同时曝光的系统复杂且价格昂贵,基于单幅低动态范围图像的拓展方法易丢失欠曝光或过曝光区域的细节信息,且多用于较好的照明条件。针对低照度动态场景成像,研究了一种基于双通道低照度CMOS相机的高动态范围图像融合方法,对双通道CMOS相机采集低照度动态场景两幅不同曝光图像,依据累计直方图拓展原则分别进行动态范围拓展,并采用像素级融合方法对动态范围拓展的序列图像进行融合。实验表明,动态范围拓展融合方法可满足低照度动态场景下获取高动态范围图像的应用要求,获得更佳的成像质量。

High dynamic range imaging technology can reflect scene information comprehensively and effectively,which is beneficial for obtaining higher imaging qualities in high dynamic range scenes.However,the classic high dynamic range image fusion method of using a single camera through multiple-exposure fusion tends to result in the“ghost”problem in a dynamic scene,whereas the method of using multiple sensors in a simultaneous exposure system is complicated and expensive.Meanwhile,an extension method based on a single low dynamic range image loses details easily in underexposed or overexposed areas.These methods are often used under better lighting conditions.Hence,a high dynamic range image fusion method based on a dual-channel low-light-level(L3)CMOS camera is proposed for low illumination dynamic scenes.First,an image acquisition platform built using a dual-channel L3 CMOS camera is used to collect two images with different exposures for low illumination dynamic scenes.Based on the accumulative histogram,the principle of dynamic range extension is established,and the two images collected by the system are extended.Finally,the pixel level fusion method is used to fuse the sequence images after the dynamic range extension.The results show that the method of dynamic range extension fusion can yield high dynamic range images under L3 dynamic scenes as well as better imaging quality.