CAJ | 학술논문

水下视频成像是海洋探测的关键技术，但是海底的特殊环境造成海底图像存在细节模糊、光照不均等问题。为此提出一种基于动态范围扩展的海底视频图像增强算法，该算法可以同时处理因光照不均而引起的图像曝光过度和曝光不足现象。首先，构造映射函数判断图像曝光过度和曝光不足的区域；然后，计算图像的动态范围，利用图像的“闲置空间”对图像曝光过度和曝光不足区域同时进行动态扩展；最后将图像转换到YCbCr空间对扩展后的图像进行亮度通道的直方图均衡化。实验结果表明，和已有算法比较，新算法既可以避免传统的直方图均衡化产生的图像过增强，提高了图像的清晰度，又可以修复图像因光照不均丢失的像素信息，显著改善图像细节。
수하시빈성상시해양탐측적관건기술，단시해저적특수배경조성해저도상존재세절모호、광조불균등문제。위차제출일충기우동태범위확전적해저시빈도상증강산법，해산법가이동시처리인광조불균이인기적도상폭광과도화폭광불족현상。수선，구조영사함수판단도상폭광과도화폭광불족적구역；연후，계산도상적동태범위，이용도상적“한치공간”대도상폭광과도화폭광불족구역동시진행동태확전；최후장도상전환도YCbCr공간대확전후적도상진행량도통도적직방도균형화。실험결과표명，화이유산법비교，신산법기가이피면전통적직방도균형화산생적도상과증강，제고료도상적청석도，우가이수복도상인광조불균주실적상소신식，현저개선도상세절。
Underwater video imaging is the key technology of ocean exploration, but the special circumstance of the seabed causes to some problems on image such as fuzzy details, and uneven illumination and other issues. An undersea video image enhancement algorithm based on dynamic range expansion was proposed in this paper, which can handle image over/under-exposed phenomenon caused by uneven illumination. Firstly, The algorithm constructed a mapping function to determine the over/under-exposed region of the input image. Then, calculated the dynamic range of the image and used the“idle space”to dynamic expanding for over/under-exposed region simultaneously. Finally, The processed image was converted to YCbCr space to separate luminance channel for histogram equalization. The experiment results illustrate that the new method not only avoids unnatural results of image caused by traditional histogram equalization, but repairs missing pixel information, improves the clarity and details of image significantly.