摘要
针对高空颠簸环境影响无人机采集延时稳定图像问题,提出了一种适用于悬停拍摄及移动拍摄的航拍视频防抖算法。通过无人机摄像头获取延时摄影视频,提取全局范围内的部分视频帧进行直方图分布比较,进而确定视频是否是在无人机移动状态下拍摄的,并将视频划分为包含与不包含摄像机主动运动两类。对于包含摄像机主动运动的一类,首先,采用FAST角点检测加光流法进行特征点提取配对;其次,利用RANSAC算法剔除误匹配特征点并进行摄像机运动轨迹估计;最后,利用高斯滤波对运动估计参数进行平滑以得到稳定的摄像机运动轨迹。对于不包含摄像机主动运动的一类,首先,对首帧进行网格划分并基于Harris矩阵提取各网格的特征点;其次,在后续帧对这些特征点进行光流追踪;再次,通过反向光流及Harris矩阵计算,增加特征点约束,完成特征点提取及匹配;最后,利用保留的特征点估计后续帧至首帧的稳定变换。利用该算法对视频进行场景分类及画面稳定,实验结果表明:视频分类模块能正确区分两类视频;对比其他两种方法,稳定后的视频图像平均峰值信噪比提升更大;对于不含摄像机主动运动的视频,可实现画面绝对稳定,图像平均峰值信噪比提升超过39%,而其他两种方法仅提升10%~12%。
Aiming at the problem of high altitude turbulence environment to the time-delay stable image acquisition of UAV,an anti-shaking algorithm for aerial video was proposed for hovering shooting and moving shooting.Firstly from the time-delay photography video captured the UAV camera,some video frames were extracted globally to compare their histogram distributions.This comparison could identify whether the video contained active camera motion or not,and help categorize the video accordingly.For videos with active camera motion,FAST corner detection and optical flow methods were used to extract and match feature points.The RANSAC algorithm could remove all mismatched feature points,and estimate the camera′s motion trajectory.The resulting motion estimation parameters were then smoothed using Gaussian filtering,producing a stable camera motion trajectory.For videos without active camera motion,the first frame was divided into grids and feature points were extracted based on Harris matrix.Optical flow tracking was carried out on these feature points in subsequent frames.Reverse optical flow and Harris matrix calculation were used to extract and match feature points,to increase the constraint of feature points.Finally,the retained feature points were used to estimate the stable transformation from subsequent frames to the first frame.Experimental results showed that the video classification module could correctly distinguish between the two types of videos.The algorithm was used to classify the video scene and stabilize the picture.Compared to other methods,this algorithm could improve the average peak signal-to-noise ratio of stabilized video images the most.For videos without active camera motion,the image could be absolutely stable,and the average peak signal-to-noise ratio of the image was increased by more than 39%,while the other two methods only by 10% to 12%.
作者
余松森
龙嘉濠
周诺
梁军
YU Songsen;LONG Jiahao;ZHOU Nuo;LIANG Jun(School of Software,South China Normal University,Foshan 528225,China)
出处
《郑州大学学报（工学版）》
CAS
北大核心
2024年第5期77-85,共9页
Journal of Zhengzhou University（Engineering Science）
基金
广东省基础与应用基础研究基金区域联合基金项目(2022A1515140110)
广东省基础与应用基础研究基金区域联合基金项目(重点项目)(2020B1515120089)
国家自然科学基金资助项目(61172156)。
关键词
无人机
视频稳定
特征提取
运动估计
峰值信噪比
UAV
video stabilization
feature extraction
motion estimation
peak signal-to-noise ratio
