In the daily application of an iris-recognition-at-a-distance(IAAD)system,many ocular images of low quality are acquired.As the iris part of these images is often not qualified for the recognition requirements,the mor...In the daily application of an iris-recognition-at-a-distance(IAAD)system,many ocular images of low quality are acquired.As the iris part of these images is often not qualified for the recognition requirements,the more accessible periocular regions are a good complement for recognition.To further boost the performance of IAAD systems,a novel end-to-end framework for multi-modal ocular recognition is proposed.The proposed framework mainly consists of iris/periocular feature extraction and matching,unsupervised iris quality assessment,and a score-level adaptive weighted fusion strategy.First,ocular feature reconstruction(OFR)is proposed to sparsely reconstruct each probe image by high-quality gallery images based on proper feature maps.Next,a brand new unsupervised iris quality assessment method based on random multiscale embedding robustness is proposed.Different from the existing iris quality assess-ment methods,the quality of an iris image is measured by its robustness in the embedding space.At last,the fusion strategy exploits the iris quality score as the fusion weight to coalesce the complementary information from the iris and periocular regions.Extensive experi-mental results on ocular datasets prove that the proposed method is obviously better than unimodal biometrics,and the fusion strategy can significantly improve therecognition performance.展开更多
Three-dimensional(3D)reconstruction based on aerial images has broad prospects,and feature matching is an important step of it.However,for high-resolution aerial images,there are usually problems such as long time,mis...Three-dimensional(3D)reconstruction based on aerial images has broad prospects,and feature matching is an important step of it.However,for high-resolution aerial images,there are usually problems such as long time,mismatching and sparse feature pairs using traditional algorithms.Therefore,an algorithm is proposed to realize fast,accurate and dense feature matching.The algorithm consists of four steps.Firstly,we achieve a balance between the feature matching time and the number of matching pairs by appropriately reducing the image resolution.Secondly,to realize further screening of the mismatches,a feature screening algorithm based on similarity judgment or local optimization is proposed.Thirdly,to make the algorithm more widely applicable,we combine the results of different algorithms to get dense results.Finally,all matching feature pairs in the low-resolution images are restored to the original images.Comparisons between the original algorithms and our algorithm show that the proposed algorithm can effectively reduce the matching time,screen out the mismatches,and improve the number of matches.展开更多
针对现有脑部医学图像融合算法存在的融合图像细节模糊和边缘性差等问题,设计一种扩张金字塔特征提取算法,由特征提取器、特征融合器和特征重构器3部分组成。特征提取器由扩张金字塔特征模块提取浅层和深层图像特征的结合,防止图像细节...针对现有脑部医学图像融合算法存在的融合图像细节模糊和边缘性差等问题,设计一种扩张金字塔特征提取算法,由特征提取器、特征融合器和特征重构器3部分组成。特征提取器由扩张金字塔特征模块提取浅层和深层图像特征的结合,防止图像细节信息的丢失;特征融合器采用改进的功能能量比(Functional Energy Ratio,FER)特征融合策略增强融合图像边缘信息;特征重构器由4层卷积构成归一化图像。实验结果表明,相较于当前通用的脑部融合算法,所提出的算法具有较好的视觉效果和细节信息,客观评价指标有更好的表现。展开更多
为解决山地地形起伏大、无人机飞行高度高导致图像中尺度小且纹理模糊的松枯死木识别困难问题,该研究提出了一种在特征层级进行超分辨率重建的YOLOv5松枯死木识别算法。在YOLOv5网络中添加选择性核特征纹理迁移模块生成有细节纹理的高...为解决山地地形起伏大、无人机飞行高度高导致图像中尺度小且纹理模糊的松枯死木识别困难问题,该研究提出了一种在特征层级进行超分辨率重建的YOLOv5松枯死木识别算法。在YOLOv5网络中添加选择性核特征纹理迁移模块生成有细节纹理的高清检测特征图,自适应改变感受野的机制分配权重,将更多注意力集中在纹理细节,提升了小目标和模糊目标的识别精度。同时,使用前景背景平衡损失函数抑制背景噪声干扰,增加正样本的梯度贡献,改善正负样本分布不平衡问题。试验结果表明,改进后算法在交并比(intersection over union,IoU)阈值取0.5时的平均精度均值(mean average precision,mAP50)为92.7%,mAP50~95(以步长0.05从0.5到0.95间取IoU阈值下的平均mAP)为62.1%,APsmall(小目标平均精度值)为53.2%,相比于原算法mAP50提高了3.2个百分点,mAP50~95提升了8.3个百分点,APsmall提升了15.8个百分点。不同算法对比分析表明,该方法优于Faster R-CNN、YOLOv4、YOLOX、MT-YOLOv6,QueryDet、DDYOLOv5等深度学习算法,mAP50分别提高了16.7、15.3、2.5、2.8、12.3和1.2个百分点。改进后松枯死木识别算法具有较高精度,有效缓解了小目标与纹理模糊目标识别困难问题,为后续疫木清零提供技术支持。展开更多
基金This work was supported by National Natural Science Foundation of China(Nos.62006225,61906199 and 62071468)the Strategic Priority Research Program of Chinese Academy of Sciences(CAS),China(No.XDA 27040700)sponsored by The Beijing Nova Program,China(Nos.Z201100006820050 and Z211100002121010).
文摘In the daily application of an iris-recognition-at-a-distance(IAAD)system,many ocular images of low quality are acquired.As the iris part of these images is often not qualified for the recognition requirements,the more accessible periocular regions are a good complement for recognition.To further boost the performance of IAAD systems,a novel end-to-end framework for multi-modal ocular recognition is proposed.The proposed framework mainly consists of iris/periocular feature extraction and matching,unsupervised iris quality assessment,and a score-level adaptive weighted fusion strategy.First,ocular feature reconstruction(OFR)is proposed to sparsely reconstruct each probe image by high-quality gallery images based on proper feature maps.Next,a brand new unsupervised iris quality assessment method based on random multiscale embedding robustness is proposed.Different from the existing iris quality assess-ment methods,the quality of an iris image is measured by its robustness in the embedding space.At last,the fusion strategy exploits the iris quality score as the fusion weight to coalesce the complementary information from the iris and periocular regions.Extensive experi-mental results on ocular datasets prove that the proposed method is obviously better than unimodal biometrics,and the fusion strategy can significantly improve therecognition performance.
基金This work was supported by the Equipment Pre-Research Foundation of China(6140001020310).
文摘Three-dimensional(3D)reconstruction based on aerial images has broad prospects,and feature matching is an important step of it.However,for high-resolution aerial images,there are usually problems such as long time,mismatching and sparse feature pairs using traditional algorithms.Therefore,an algorithm is proposed to realize fast,accurate and dense feature matching.The algorithm consists of four steps.Firstly,we achieve a balance between the feature matching time and the number of matching pairs by appropriately reducing the image resolution.Secondly,to realize further screening of the mismatches,a feature screening algorithm based on similarity judgment or local optimization is proposed.Thirdly,to make the algorithm more widely applicable,we combine the results of different algorithms to get dense results.Finally,all matching feature pairs in the low-resolution images are restored to the original images.Comparisons between the original algorithms and our algorithm show that the proposed algorithm can effectively reduce the matching time,screen out the mismatches,and improve the number of matches.
文摘针对现有脑部医学图像融合算法存在的融合图像细节模糊和边缘性差等问题,设计一种扩张金字塔特征提取算法,由特征提取器、特征融合器和特征重构器3部分组成。特征提取器由扩张金字塔特征模块提取浅层和深层图像特征的结合,防止图像细节信息的丢失;特征融合器采用改进的功能能量比(Functional Energy Ratio,FER)特征融合策略增强融合图像边缘信息;特征重构器由4层卷积构成归一化图像。实验结果表明,相较于当前通用的脑部融合算法,所提出的算法具有较好的视觉效果和细节信息,客观评价指标有更好的表现。
文摘针对现有超分辨率(super-resolution)重建算法重建出的图像存在高频细节丢失、结构化失真的问题,结合多尺度混合注意力网络,给出一种新的重建算法。首先,设计了一种多尺度残差模块(multi-scale residual module,MRM),提取不同尺度信息的特征并进行融合来获取包含更多信息的浅层特征;其次,采用残差混合注意力模块(residual hybrid attention module,RHAM),依次沿着通道和空间2个不同的维度增强网络特征提取能力,进行自适应的特征优化,提高高频特征的复用;最后,通过重建模块对提取的特征进行增强,获取相应的高分辨率图像。在基准数据集上进行测试,实验结果表明:文中提出的算法相较主流图像SR算法,在放大尺度为2、3、4倍时峰值信噪比(peak signal to noise ratio,PSNR)平均提高了0.104、0.224、0.146 dB,结构相似性(structural similarity index measure,SSIM)平均提高了0.0349、0.0276、0.0181。该算法能更有效地利用原始图像信息,重建出的图像在边缘和纹理细节等方面有一定的提高。
文摘为解决山地地形起伏大、无人机飞行高度高导致图像中尺度小且纹理模糊的松枯死木识别困难问题,该研究提出了一种在特征层级进行超分辨率重建的YOLOv5松枯死木识别算法。在YOLOv5网络中添加选择性核特征纹理迁移模块生成有细节纹理的高清检测特征图,自适应改变感受野的机制分配权重,将更多注意力集中在纹理细节,提升了小目标和模糊目标的识别精度。同时,使用前景背景平衡损失函数抑制背景噪声干扰,增加正样本的梯度贡献,改善正负样本分布不平衡问题。试验结果表明,改进后算法在交并比(intersection over union,IoU)阈值取0.5时的平均精度均值(mean average precision,mAP50)为92.7%,mAP50~95(以步长0.05从0.5到0.95间取IoU阈值下的平均mAP)为62.1%,APsmall(小目标平均精度值)为53.2%,相比于原算法mAP50提高了3.2个百分点,mAP50~95提升了8.3个百分点,APsmall提升了15.8个百分点。不同算法对比分析表明,该方法优于Faster R-CNN、YOLOv4、YOLOX、MT-YOLOv6,QueryDet、DDYOLOv5等深度学习算法,mAP50分别提高了16.7、15.3、2.5、2.8、12.3和1.2个百分点。改进后松枯死木识别算法具有较高精度,有效缓解了小目标与纹理模糊目标识别困难问题,为后续疫木清零提供技术支持。
