共查询到20条相似文献,搜索用时 31 毫秒
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程恩 《海洋通报(英文版)》2001,3(2)
A new method of coding and decoding in the system of underwater image transmission is introduced, including the rapid digital frequency synthesizer in multiple frequency shift keying,image data generator, image grayscale decoder with intelligent fuzzy algorithm, image restoration and display on microcomputer. 相似文献
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不等保护能力纠错编码在水声信息传输中应用的研究 总被引:1,自引:0,他引:1
通过分析水声信道的特性和水声信息源的特点 ,结合信道编码理论与技术的最新进展 ,提出了一种全新的、能适合于水声信息传输的、高性能的不等保护能力纠错编解码方法。 相似文献
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水声信道高速率数据传输技术 总被引:2,自引:0,他引:2
本文介绍近年来水声信道高速率数所传输技术的一些研究进展,并结合本所研究的水声数据遥测,数字语音通讯和视频图像传输实验样机,讨论了具有抗多途干扰的声传输系统在调制信号设计及信号处理上所采用的关键技术。 相似文献
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该文将海水中图象传输特性的研究与用此传输特性进行水下模糊图象恢复结合起来 ,得到一套测量水体传递函数及进行水下图象处理的方法。采用维纳 (Wiener)滤波和卡尔曼 (Kalman)滤波算法 ,对模糊图象进了恢复。结果表明 ,利用计算机采用一定的算法对散射性质已知的水体造成的图象模糊可以进行有效的复原 ,且良好效果。 相似文献
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水下对接传输技术作为自主水下机器人(autonomous underwater vehicle,简称AUV)水下能源补给及数据传输的重要方式,受到国内外的重点关注,目前采用的水下对接传输方式主要分为接驳插拔传输及无线感应传输。在探究国内外AUV水下对接研究概况的基础上,归纳、总结以上两种传输方式的研究现状,分析对比其在对接传输效率、发展限制因素、对接控制技术等方面的区别。通过分析发现,接驳插拔传输在传输效率及功率方面具备优势,无线感应传输则具有更高的简易性、经济性。此发现为不同作业需求下传输方式的选择提供了基础。通过技术发展限制因素对比得出,在未来技术发展方向上,接驳插拔传输技术需提升系统稳定性、灵活性及费效比,无线感应传输需解决能量损耗、系统鲁棒性及涡旋损耗等问题。对两种传输技术未来发展前景及方向的预测,能够为AUV水下传输的发展提供重要参考。 相似文献
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Jenhwa Guo Sheng-Wen Cheng Cheng-Yang Ying Te-Chih Liu 《Oceanic Engineering, IEEE Journal of》2003,28(1):55-61
Describes an image registration method for underwater inspection tasks. A remotely operated vehicle equipped with a video camera and a scanning sonar is used as the testbed vehicle. Each image of the underwater scene is saved along with the video camera's position and orientation. The images are then combined to create a large composite picture of the underwater structure being inspected. This method is based upon a maximum a posteriori estimation technique and provides smooth and robust estimates of image shifts. Our results demonstrate the feasibility of this highly promising underwater inspection procedure. 相似文献
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Underwater acoustic communication in the multipath environment encountered in shallow water is restricted mostly by signal fading. It degrades the signal detection and time synchronization required for reliable acoustic communication. An approach to time synchronization and to the frequency diversity method is presented. A communication algorithm for obtaining a reliable acoustic underwater link, and offering an easy-to-implement decoding scheme is introduced, and system realization is described 相似文献
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针对水下图像对比度偏低,细节模糊的问题,本文提出基于非锐化掩模引导滤波的细节增强方法。首先由原始图像做引导图进行滤波得到细节层图像,并对细节层使用噪声检测的中值滤波去除斑点噪声;然后对原始图像进行基于均值滤波的非锐化掩模,得到锐化图像,并将锐化图像作为引导图对原始图像进行引导滤波,获取基础层图像;最后将滤波后的细节层进行增益后与引导滤波获取的基础层进行叠加,达到增强水下图像细节的目的。并通过信息熵、局部对比度和平均梯度3种客观评价指标对图像处理结果进行了对比分析,主观和客观测试结果表明,本文采用的算法能够有效提高图像对比度以及增强细节信息,有利于提高水下图像资料解释的准确性。 相似文献
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随着海洋强国战略的推进和实施,水下传感器网络广泛应用于海洋资源探测、污染监测、辅助导航和水下军事侦察等领域,具有十分重要的意义。由于水下传感器所携电池充电或更换困难,如何减小传输能耗、在传感器能量受限的情况下提升网络生存期是亟须解决的关键问题之一。据此,提出了一种动态蚁群路由算法,考虑了每次传输后的节点剩余能量,作为路径优化的条件之一,基于蚁群算法在每次传输中选择最优路径,并在每次传输完成后更新路由表,让更多的节点参与信息传输,以提高节点的利用率。仿真结果表明:动态蚁群路由算法同时兼顾了能耗平衡和最小传输能耗,大大提高了网络生存期。分析结果对水下传感器网络的路由协议设计有一定的参考意义。 相似文献
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水声通信中的鲁棒图像编码研究 总被引:2,自引:1,他引:2
由于受各种因素的影响,水下声信道是一种传输差错率较高的信道。标准化的图像编码系统(例如JPEC;H.263,MPEG等)使用了相似的压缩技术,它们往往存在严重的错误扩散,甚至单个错误比特就可能破坏整幅图像,所以一般不适合作为水下声信道图像传输的编码方案。文章针对常用的图像编码的缺点,利用定长编码技术,提出了一种高鲁棒性的图像压缩方案。实验表明在压缩率1.25比特/象素时,压缩后的图像仍然保持了较好的质量,并且能够较好地抵抗信道误码,提高了水下声信道图像传输的质量。 相似文献
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A detection model of underwater topography with a series of SAR images acquired at different time 总被引:1,自引:1,他引:0
underwater topography is one of oceanic features detected by Synthetic Aperture Radar. Underwater topography SAR imaging mechanism shows that tidal current is the important factor for underwater topography SAR imaging. Thus under the same wind field condition, SAR images for the same area acquired at different time include different information of the underwater topography. To utilize synchronously SAR images acquired at different time for the underwater topography SAR detection and improve the precision of detection, based on the detection model of underwater topography with single SAR image and the periodicity of tidal current, a detection model of underwater topography with a series of SAR images acquired at different time is developed by combing with tide and tidal current numerical simulation. To testify the feasibility of the presented model, Taiwan Shoal located at the south outlet of Taiwan Strait is selected as study area and three SAR images are used in the underwater topography detection. The detection results are compared with the field observation data of water depth carried out by R/V Dongfanghong 2, and the errors of the detection are compared with those of the single SAR image. All comparisons show that the detection model presented in the paper improves the precision of underwater topography SAR detection, and the presented model is feasible. 相似文献
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摄影测量的处理工作主要依赖于自动的影像匹配技术,如果影像之间的辐射差异越小,即摄影基线越短,则自动匹配精度越高,但是从理论上说基线越短空间交会精度越低,而水下由于众多干扰因素影响,空间交会的精度更低。针对这一难题,从理论上分析了空间交会精度的主要影响因子,考虑涉水拍摄环境时水对光线的折射影响,提出将超短基线多度重叠影像应用于涉水摄影测量,并通过双介质空间交会实验和水下空间交会实验,验证了在涉水情况下,利用超短基线多度重叠影像能够大幅度地提高水下目标物的空间交会精度。得出的结论对越来越多的涉水摄影测量应用具有积极的参考价值。 相似文献
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为了在恶劣的水声信道中确保数据的可靠传输,采用性能优异的Turbo码,以6711DSP为核心处理单元构建译码系统。系统采用戈泽尔算法进行跳频的软解调,迭代的软输出维特比译码算法(SOVA)进行译码。系统经过实验室水池的试验,证实能保证译码的实时性及其在恶劣信道中数据传输的正确性,具有相当优异的性能。 相似文献
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An experiment on the correction of underwater images distorted by waves at the air-water interface was conducted using a laboratory modeling installation intended for experimental examination of light and image transfer across a water surface covered with waves. A digital color camera was used for the simultaneous formation of the image of the underwater test object through the disturbed surface and of the superimposed glitter pattern. Both images are spectrally separated. Processing the glitter pattern makes it possible to obtain the values of the surface slopes at a limited number of points and to use these slopes for retrieval of image fragments. The total corrected image is formed by integration of about 300 partially corrected fragments. This image is close to that obtained through a wave-free water surface. 相似文献