Journal of Computer Applications ›› 2021, Vol. 41 ›› Issue (8): 2318-2323.DOI: 10.11772/j.issn.1001-9081.2020101637

Special Issue: 多媒体计算与计算机仿真

• Multimedia computing and computer simulation • Previous Articles     Next Articles

Nonlinear constraint based quasi-homography warps for image stitching

WANG Huai, WANG Zhanqing   

  1. School of Science, Wuhan University of Technology, Wuhan Hubei 430070, China
  • Received:2020-10-21 Revised:2020-12-11 Online:2021-08-10 Published:2021-01-27

非线性约束下的准单应变换图像拼接算法

王怀, 王展青   

  1. 武汉理工大学 理学院, 武汉 430070
  • 通讯作者: 王怀
  • 作者简介:王怀(1995-),男,湖北荆州人,硕士研究生,主要研究方向:图像拼接;王展青(1965-),男,湖北咸宁人,教授,博士,主要研究方向:数字图像处理、模式识别、信息计算。

Abstract: In order to solve the problem of longitudinal projection distortion in non-overlapping regions of images caused by the quasi-homography warp algorithm for image stitching, an image stitching algorithm based on nonlinear constraint was proposed. Firstly, the nonlinear constraint was used to smoothly transit the image regions around the dividing line. Then, the linear equation of quasi-homography warp was replaced by a parabolic equation. Finally, the mesh-based method was used to improve the speed of image texture mapping and the method based on optimal stitching line was used to fuse the images. For images of 1 200 pixel×1 600 pixel, the time consumption range of texture mapping by the proposed algorithm is 4 s to 7 s, and the proposed algorithm has the average deviation degree of diagonal structure is 11 to 31. Compared with the quasi-homography warp algorithm for image stitching, the proposed algorithm has the time consumption of texture mapping reduced by 55% to 67%, and the average deviation degree of diagonal structure reduced by 36% to 62%. It can be seen that the proposed algorithm not only corrects the oblique diagonal structure, but also improves the efficiency of image stitching. Experimental results show that the proposed algorithm has better results in improving the visual effect of stitched images.

Key words: image stitching, non-overlapping region, nonlinear constraint, image warping, distortion correction, quasi-homography warp

摘要: 针对准单应变换图像拼接算法造成图像非重叠区域存在纵向投影失真的问题,提出了一种基于非线性约束的图像拼接算法。首先,该算法利用非线性约束来平滑过渡分界线左右的图像区域;然后,利用抛物线方程替换准单应变换的直线方程;最后,利用网格化的方法提高图像纹理映射的速度,并利用基于最佳缝合线的方法融合图像。对于尺寸为1 200像素×1 600像素的图像,所提算法的纹理映射耗时波动范围为4~7 s,并且其斜线结构的平均偏离程度在11~31。与准单应变换图像拼接算法相比较,所提算法的纹理映射的耗时降低了55%~67%,斜线结构的平均偏离程度降低了36%~62%,可见所提算法既矫正了斜线几何结构也提高了图像拼接效率。实验结果表明,所提算法在改善拼接图像视觉效果的方面具有更好的结果。

关键词: 图像拼接, 非重叠区域, 非线性约束, 图像变形, 畸变矫正, 准单应变换

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