A novel high spectrum efficiency channel encoding method called overlapped code division multiplexing (OvCDM) is presented. It is a convolutional encoding method with code rate greater than 1. Compared with traditio...A novel high spectrum efficiency channel encoding method called overlapped code division multiplexing (OvCDM) is presented. It is a convolutional encoding method with code rate greater than 1. Compared with traditional coded modulation (CM) technologies, OvCDM emphasizes the constrain relation between encoded codes. It is actually a blind modulation. The simulation results in the additive white Gaussian noise (AWGN) channel indicate that OvCDM can significantly improve spectrum efficiency of mobile communications systems. Meanwhile, the proposed OvCDM can ensure high decoding performance.展开更多
In the context of object oriented video coding, the encoding of segmentation maps defined by contour networks is particularly critical. In this paper, we present a lossy contour network encoding algorithm where both t...In the context of object oriented video coding, the encoding of segmentation maps defined by contour networks is particularly critical. In this paper, we present a lossy contour network encoding algorithm where both the rate distortion contour encoding based on maximum operator and the prediction error for the current frame based on quadratic motion model are combined into a optimal polygon contour network compression scheme. The bit rate for the contour network can be further reduced by about 20% in comparison with that in the optimal polygonal boundary encoding scheme using maximum operator in the rate distortion sense.展开更多
针对当前加密图像可逆信息隐藏方法中存在的嵌入率低,标记图像直接解密后视觉质量差的问题,提出一种位平面分块编码的加密图像可逆信息隐藏方法。算法通过2D sine logistic混沌映射对图像分块加密,保留块内像素的相关性。将加密后的图...针对当前加密图像可逆信息隐藏方法中存在的嵌入率低,标记图像直接解密后视觉质量差的问题,提出一种位平面分块编码的加密图像可逆信息隐藏方法。算法通过2D sine logistic混沌映射对图像分块加密,保留块内像素的相关性。将加密后的图像块化分成8个位平面,在低阶位平面中,根据块平面内0元素和1元素的分布情况,进行编码压缩,利用压缩后块平面内生成冗余空间进行机密信息的嵌入,图像的其余位平面部分则保持不变。在接收端,接收者获取密钥后可以进行信息提取,图像解密和图像的无损恢复。利用标准图像库中图像进行仿真实验,结果表明:随着可嵌入低位平面数的增加,算法的嵌入容量逐渐增大,在低阶平面数取3时,该算法保持较高的嵌入率时,仍然使得直接解密后的图像仍具有较高的PSNR值。展开更多
图像遥测系统是红外制导武器研制过程中必不可少的手段,但是由于导引头图像运动剧烈、携带信息量大,因此,适用于普通场景的码率控制算法难以直接应用于导引头图像遥测系统当中。对JM19.0使用的JVT-G012r1码率控制算法进行了分析,并根据...图像遥测系统是红外制导武器研制过程中必不可少的手段,但是由于导引头图像运动剧烈、携带信息量大,因此,适用于普通场景的码率控制算法难以直接应用于导引头图像遥测系统当中。对JM19.0使用的JVT-G012r1码率控制算法进行了分析,并根据导引头图像的特点提出一种结合感兴趣区域(Region of Interest,ROI)编码的码率控制算法,有效地对可用比特进行分配。同时以JM19.0软件为基础,对提出算法进行了仿真验证。仿真结果表明,与JVT-G012r1算法相比,该算法可以更好地适应导引头遥测图像的特点,提高感兴趣区域的图像质量,方便科研人员进一步分析研究。展开更多
基金supported by the National Natural Science Foundation of China(90604035)
文摘A novel high spectrum efficiency channel encoding method called overlapped code division multiplexing (OvCDM) is presented. It is a convolutional encoding method with code rate greater than 1. Compared with traditional coded modulation (CM) technologies, OvCDM emphasizes the constrain relation between encoded codes. It is actually a blind modulation. The simulation results in the additive white Gaussian noise (AWGN) channel indicate that OvCDM can significantly improve spectrum efficiency of mobile communications systems. Meanwhile, the proposed OvCDM can ensure high decoding performance.
基金upported by the National Natural Science Foundation of China!( 6 95 72 0 2 3)bytheKeyProjectfromtheShanghaiEducationComm
文摘In the context of object oriented video coding, the encoding of segmentation maps defined by contour networks is particularly critical. In this paper, we present a lossy contour network encoding algorithm where both the rate distortion contour encoding based on maximum operator and the prediction error for the current frame based on quadratic motion model are combined into a optimal polygon contour network compression scheme. The bit rate for the contour network can be further reduced by about 20% in comparison with that in the optimal polygonal boundary encoding scheme using maximum operator in the rate distortion sense.
文摘针对当前加密图像可逆信息隐藏方法中存在的嵌入率低,标记图像直接解密后视觉质量差的问题,提出一种位平面分块编码的加密图像可逆信息隐藏方法。算法通过2D sine logistic混沌映射对图像分块加密,保留块内像素的相关性。将加密后的图像块化分成8个位平面,在低阶位平面中,根据块平面内0元素和1元素的分布情况,进行编码压缩,利用压缩后块平面内生成冗余空间进行机密信息的嵌入,图像的其余位平面部分则保持不变。在接收端,接收者获取密钥后可以进行信息提取,图像解密和图像的无损恢复。利用标准图像库中图像进行仿真实验,结果表明:随着可嵌入低位平面数的增加,算法的嵌入容量逐渐增大,在低阶平面数取3时,该算法保持较高的嵌入率时,仍然使得直接解密后的图像仍具有较高的PSNR值。
文摘图像遥测系统是红外制导武器研制过程中必不可少的手段,但是由于导引头图像运动剧烈、携带信息量大,因此,适用于普通场景的码率控制算法难以直接应用于导引头图像遥测系统当中。对JM19.0使用的JVT-G012r1码率控制算法进行了分析,并根据导引头图像的特点提出一种结合感兴趣区域(Region of Interest,ROI)编码的码率控制算法,有效地对可用比特进行分配。同时以JM19.0软件为基础,对提出算法进行了仿真验证。仿真结果表明,与JVT-G012r1算法相比,该算法可以更好地适应导引头遥测图像的特点,提高感兴趣区域的图像质量,方便科研人员进一步分析研究。