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基于\ell_1 范数与梯度约束的无人机图像拼接方法

UAV Image Stitching Method Based on \ell_1 -Norm and Gradient Constraints

  • 摘要: 无人机图像拼接技术通过高效整合航拍数据,为低空经济发展提供重要支撑。针对低纹理场景下无人机图像特征点提取不足导致的配准精度下降、拼接错位以及重影等问题,提出一种基于 \ell_1 范数与梯度约束的无人机图像拼接方法。首先,通过联合提取目标图像与参考图像的特征点和特征线,构建多特征描述子以提升匹配鲁棒性,有效改善图像错位问题。其次,采用 \ell_1 范数进行色差度量并结合梯度约束构建能量函数,引导接缝优先通过图像高相似度的连续区域;最后,基于图切割算法在重叠区域搜索最优缝合路径,并采用泊松融合技术实现拼接边界的自然过渡。选取两组典型无人机图像数据集,通过与SPW,LPC和MSF三种主流方法的对比测试,验证本方法在拼接精度和视觉效果上的优势。结果表明:相较于SPW,LPC和MSF方法,本方法在客观指标上优势显著,其SSIM值分别提高2.97%,5.87%,3.07%,PSNR值分别提高0.595,0.848,0.841 dB;在主观视觉质量方面,本方法有效缓解了拼接错位和重影问题,同时更好地保持了图像结构和纹理细节的完整性。定量和定性结果共同证实了该方法在低纹理场景下的优越性能。

     

    Abstract: Unmanned aerial vehicle (UAV) image stitching technology provides crucial support for the development of the low-altitude economy through efficient integration of aerial data. To address issues such as low registration accuracy, misalignment, and ghosting caused by insufficient feature point extraction in low-texture UAV images, an \ell_1 -norm and gradient-constrained UAV image stitching method was proposed. First, feature points and feature lines of the target image and the reference image were jointly extracted to construct a multi-feature descriptor, enhancing matching robustness and effectively improving image misalignment. Second, the \ell_1 -norm was used for color difference measurement, and an energy function was constructed with gradient constraints to guide the seam to preferentially pass through highly similar continuous regions. Finally, the graph-cut algorithm was applied to search for the optimal stitching path in the overlapping area, and Poisson blending was employed to achieve a natural transition at the stitching boundary. Two sets of typical drone image datasets were selected, and comparative tests with three mainstream methods (SPW, LPC, and MSF) were conducted to verify the superiority of the proposed method in terms of stitching accuracy and visual effects.The results show that compared with SPW, LPC, and MSF, the SSIM values of the proposed method are improved by 2.97%, 5.87%, and 3.07% respectively, while the PSNR values are increased by 0.595, 0.848, 0.841 dB respectively. In terms of visual effects, misalignment and ghosting during the stitching process are significantly improved by the proposed method, with structural integrity and texture details of objects being better preserved, resulting in enhanced overall quality of UAV image stitching. Both quantitative and qualitative analyses fully demonstrate the superior performance of the proposed method in low-texture scenarios.

     

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