CAJ | 학술논문

针对当前光流算法在野外光照变化条件下计算精度不高的问题, 提出一种基于改进Census变换的变分光流算法. 该算法根据图像轮廓信息自适应选择变换窗口形状, 以提高深度不连续区域图像子块信息描述的准确性; 在变换窗口内构建完整的梯度流向量描述子, 克服传统算法由于信息量不够而导致的不同图像子块区分度有限的问题;在构建二进制串时, 与基准元素越近的点排在二进制串高位, 减弱 2 帧图像因投影变形对光流求解的影响. 在TV_L1 变分光流计算框架下, 用改进的 Census 变换描述子构建光流模型中的数据项. 对图像进行高斯金字塔分解,并结合加权中值滤波进行分层光流估计. 最后以Middlebury和KITTI数据库为测试平台, 证明了文中算法的有效性.
침대당전광류산법재야외광조변화조건하계산정도불고적문제, 제출일충기우개진Census변환적변분광류산법. 해산법근거도상륜곽신식자괄응선택변환창구형상, 이제고심도불련속구역도상자괴신식묘술적준학성; 재변환창구내구건완정적제도류향량묘술자, 극복전통산법유우신식량불구이도치적불동도상자괴구분도유한적문제;재구건이진제천시, 여기준원소월근적점배재이진제천고위, 감약 2 정도상인투영변형대광류구해적영향. 재TV_L1 변분광류계산광가하, 용개진적 Census 변환묘술자구건광류모형중적수거항. 대도상진행고사금자탑분해,병결합가권중치려파진행분층광류고계. 최후이Middlebury화KITTI수거고위측시평태, 증명료문중산법적유효성.
In wild environment, the optical flow algorithm accuracy will be affected by the changing illumination. In order to solve this problem, avariational optical flow computation algorithm based on improved Census transform is proposed in this paper. In traditional Census transformation, different sub-images cannot be distinguished due to insufficient amount of information. In this algorithm, completed gradient flow descriptor in an image window is constructed to overcome this problem. Furthermore, transformation window is selected adaptively according to image contour which can improve the description accuracy in depth discontinuity areas. For building a binary string, the elements which are closer to the reference element are set in the higher order of binary string, weakening the impact of image distortion to the optical flow estimation. The improved describer is used to construct the data term in TV_L1 variable flow computation framework. Gaussian pyramid decomposition and median filtering methods are also used to estimate optical flow in the solving processing. The proposed improved Census transformation contains more local image characteristics, which has the stronger ability to resist illumination change. The proposed algorithm is tested on the benchmark of both Middlebury and KITTI comparing to the traditional Census transformation method. The experimental results demonstrate the effectiveness of the proposed method.