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Improved Small Target Detection Method for SAR Image Based on YOLOv7
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作者 YANG Ke SI Zhan-jun +1 位作者 ZHANG Ying-xue SHI Jin-yu 《印刷与数字媒体技术研究》 CAS 北大核心 2024年第5期53-62,共10页
In order to solve the problems that the current synthetic aperture radar(SAR)image target detection method cannot adapt to targets of different sizes,and the complex image background leads to low detection accuracy,an... In order to solve the problems that the current synthetic aperture radar(SAR)image target detection method cannot adapt to targets of different sizes,and the complex image background leads to low detection accuracy,an improved SAR image small target detection method based on YOLOv7 was proposed in this study.The proposed method improved the feature extraction network by using Switchable Around Convolution(SAConv)in the backbone network to help the model capture target information at different scales,thus improving the feature extraction ability for small targets.Based on the attention mechanism,the DyHead module was embedded in the target detection head to reduce the impact of complex background,and better focus on the small targets.In addition,the NWD loss function was introduced and combined with CIoU loss.Compared to the CIoU loss function typically used in YOLOv7,the NWD loss function pays more attention to the processing of small targets,so as to further improve the detection ability of small targets.The experimental results on the HRSID dataset indicate that the proposed method achieved mAP@0.5 and mAP@0.95 scores of 93.5%and 71.5%,respectively.Compared to the baseline model,this represents an increase of 7.2%and 7.6%,respectively.The proposed method can effectively complete the task of SAR image small target detection. 展开更多
关键词 Small target detection Synthetic aperture radar YOLOv7 DyHead module Switchable Around Convolution
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一种基于MDFT的频带扩展技术
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作者 潘兴德 吴超刚 李靓 《电声技术》 2015年第1期48-51,共4页
提出了一种基于离散傅里叶变换(MDFT)域的频带扩展技术,可有效地提高音频编码效率。相对于既有方法,本方法在MDFT域进行频带扩展,能与低频编码所采用的MDCT变换相协调,有效利用低频编码过程中的既有数据,通过灵活的块切换方式来有效提... 提出了一种基于离散傅里叶变换(MDFT)域的频带扩展技术,可有效地提高音频编码效率。相对于既有方法,本方法在MDFT域进行频带扩展,能与低频编码所采用的MDCT变换相协调,有效利用低频编码过程中的既有数据,通过灵活的块切换方式来有效提高高频参数编码的效率。通过由MDCT域频谱转换得到MDFT域频谱数据,避免了进行MDFT时频变换,从而在保持音频信号编码质量的前提下,有效降低了解码器的计算复杂度。 展开更多
关键词 频带扩展 音频编码 MDFT域 MDCT变换 块切换
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一个支持大量用户点播的交互式视频点播系统 被引量:1
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作者 吕春 刘娟 赵会群 《北方工业大学学报》 2004年第3期22-26,共5页
传统的视频点播系统由于采用单播方法,使得系统可以支持的并发用户数目受到限制。本系统采用多播方法,可以很好的改善这一问题,而且采用块间切换技术,使得系统在支持大量用户点播的同时满足用户的交互性操作。
关键词 视频点播 单播 多播 切换
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