This paper presents a method to detect the quantization index modulation(QIM) steganography in G.723.1 bit stream.We show that the distribution of each quantization index(codeword) in the quantization index sequence h...This paper presents a method to detect the quantization index modulation(QIM) steganography in G.723.1 bit stream.We show that the distribution of each quantization index(codeword) in the quantization index sequence has unbalanced and correlated characteristics.We present the designs of statistical models to extract the quantitative feature vectors of these characteristics.Combining the extracted vectors with the support vector machine,we build the classifier for detecting the QIM steganography in G.723.1 bit stream.The experiment shows that the method has far better performance than the existing blind detection method which extracts the feature vector in an uncompressed domain.The recall and precision of our method are all more than 90% even for a compressed bit stream duration as low as 3.6 s.展开更多
A multipurpose image watermarking technique based on DCT is proposed to notify and protect the copyright of digital products. In order to achieve this objective, the DCT coefficients of each image block are divided in...A multipurpose image watermarking technique based on DCT is proposed to notify and protect the copyright of digital products. In order to achieve this objective, the DCT coefficients of each image block are divided into two parts for embedding the visible and invisible watermarks. The visible watermark is embedded in each DC DCT coefficient and most of the AC DCT coefficients of every block, and the invisible watermark in the rest. Based on the characteristics of Human Visual System (HVS), the embedding strength of the visible watermark is varied in accordance with the underlying content of the host image. The invisible watermark is embedded in a quaternity of midrange frequencies. Experimental results show that the visible watermark is hard to remove and the invisible watermark is robust to common digital signal processing operations.展开更多
We propose a joint look-up-table(LUT)-based nonlinear predistortion and digital resolution enhancement scheme to achieve high-speed and low-cost optical interconnects using low-resolution digital-to-analog converters(...We propose a joint look-up-table(LUT)-based nonlinear predistortion and digital resolution enhancement scheme to achieve high-speed and low-cost optical interconnects using low-resolution digital-to-analog converters(DACs).The LUT-based predistortion is employed to mitigate the patterndependent effect(PDE)of a semiconductor optical amplifier(SOA),while the digital resolution enhancer(DRE)is utilized to shape the quantization noise,lowering the requirement for the resolution of DAC.We experimentally demonstrate O-band intensity modulation and direct detection(IM/DD)transmission of 124-GBd 4∕6-level pulse-amplitude modulation ePAMT-4∕6 and 112-GBd PAM-8 signals over a 2-km standard single-mode fiber(SSMF)with 3∕3.5∕4-bit DACs.In the case of 40-km SSMF transmission with an SOAbased preamplifier,124-GBd on-off-keying(OOK)/PAM-3/PAM-4 signals are successfully transmitted with 1.5∕2∕3-bit DACs.To the best of our knowledge,we have achieved the highest net data rates of 235.3-Gb∕s PAM-4,289.7-Gb∕s PAM-6,and 294.7 Gb∕s PAM-8 signals over 2-km SSMF,as well as 117.6-Gb∕s OOK,173.8-Gb∕s PAM-3,and−231.8 Gb∕s PAM-4 signals over 40-km SSMF,employing low-resolution DACs.The experimental results reveal that the joint LUT-based predistortion and DRE effectively mitigate the PDE and improve the signal-to-quantization noise ratio by shaping the noise.The proposed scheme can provide a powerful solution for low-cost IM/DD optical interconnects beyond 200 Gb∕s.展开更多
We propose a robust digital watermarking algorithm for copyright protection.A stable feature is obtained by utilizing QR factorization and discrete cosine transform(DCT) techniques,and a meaningful watermark image is ...We propose a robust digital watermarking algorithm for copyright protection.A stable feature is obtained by utilizing QR factorization and discrete cosine transform(DCT) techniques,and a meaningful watermark image is embedded into an image by modifying the stable feature with a quantization index modulation(QIM) method.The combination of QR factorization,DCT,and QIM techniques guarantees the robustness of the algorithm.Furthermore,an embedding location selection method is exploited to select blocks with small modifications as the embedding locations.This can minimize the embedding distortion and greatly improve the imperceptibility of our scheme.Several standard images were tested and the experimental results were compared with those of other published schemes.The results demonstrate that our proposed scheme can achieve not only better imperceptibility,but also stronger robustness against common signal processing operations and lossy compressions,such as filtering,noise addition,scaling,sharpening,rotation,cropping,and JPEG/JPEG2000 compression.展开更多
In view of the fact that the current adaptive steganography algorithms are difficult to resist scaling attacks and that a method resisting scaling attack is only for the nearest neighbor interpolation method,this pape...In view of the fact that the current adaptive steganography algorithms are difficult to resist scaling attacks and that a method resisting scaling attack is only for the nearest neighbor interpolation method,this paper proposes an image steganography algorithm based on quantization index modulation resisting both scaling attacks and statistical detection.For the spatial image,this paper uses the watermarking algorithm based on quantization index modulation to extract the embedded domain.Then construct the embedding distortion function of the new embedded domain based on S-UNIWARD steganography,and use the minimum distortion coding to realize the embedding of the secret messages.Finally,according to the embedding modification amplitude of secret messages in the new embedded domain,the quantization index modulation algorithm is applied to realize the final embedding of secret messages in the original embedded domain.The experimental results show that the algorithm proposed is robust to the three common interpolation attacks including the nearest neighbor interpolation,the bilinear interpolation and the bicubic interpolation.And the average correct extraction rate of embedded messages increases from 50%to over 93% after 0.5 times-fold scaling attack using the bicubic interpolation method,compared with the classical steganography algorithm S-UNIWARD.Also the algorithm proposed has higher detection resistance than the original watermarking algorithm based on quantization index modulation.展开更多
Data hiding plays an important role in privacy protection and authentication,but most data hiding methods fail to achieve satisfactory performance in resisting scaling attacks and additive attacks.To this end,this pap...Data hiding plays an important role in privacy protection and authentication,but most data hiding methods fail to achieve satisfactory performance in resisting scaling attacks and additive attacks.To this end,this paper proposes a new quantization index modulation(QIM)variant based on division domains(D-QIM).It can not only resist the above two attacks well,but also adjust the performance trade-offs by controlling the parameters.Simulation results confirm the performance gain of D-QIM in terms of the bit error rate(BER).展开更多
基于MLAT多点定位的A-SMGCS系统可显著提高机场场面监视的精度。对机场场面监视雷达中数据采集系统的设计方法进行详细地阐述。利用高速A/D实时采集对数放大器输出的回波数据,经F P G A处理后,通过光纤发送至信号处理。实际工作结果表明...基于MLAT多点定位的A-SMGCS系统可显著提高机场场面监视的精度。对机场场面监视雷达中数据采集系统的设计方法进行详细地阐述。利用高速A/D实时采集对数放大器输出的回波数据,经F P G A处理后,通过光纤发送至信号处理。实际工作结果表明,该设计方案成熟、可靠,为类似的系统或项目提供一个有益的借鉴。展开更多
基金Project supported by the National Natural Science Foundation of China (No. 60970148)the National High-Tech R&D (863)Program of China (No. 2011AA010704)
文摘This paper presents a method to detect the quantization index modulation(QIM) steganography in G.723.1 bit stream.We show that the distribution of each quantization index(codeword) in the quantization index sequence has unbalanced and correlated characteristics.We present the designs of statistical models to extract the quantitative feature vectors of these characteristics.Combining the extracted vectors with the support vector machine,we build the classifier for detecting the QIM steganography in G.723.1 bit stream.The experiment shows that the method has far better performance than the existing blind detection method which extracts the feature vector in an uncompressed domain.The recall and precision of our method are all more than 90% even for a compressed bit stream duration as low as 3.6 s.
文摘A multipurpose image watermarking technique based on DCT is proposed to notify and protect the copyright of digital products. In order to achieve this objective, the DCT coefficients of each image block are divided into two parts for embedding the visible and invisible watermarks. The visible watermark is embedded in each DC DCT coefficient and most of the AC DCT coefficients of every block, and the invisible watermark in the rest. Based on the characteristics of Human Visual System (HVS), the embedding strength of the visible watermark is varied in accordance with the underlying content of the host image. The invisible watermark is embedded in a quaternity of midrange frequencies. Experimental results show that the visible watermark is hard to remove and the invisible watermark is robust to common digital signal processing operations.
基金supported by the National Key R&D Program of China(Grant No.2020YFB1806400)the China Scholarship Council(Grant No.202306230183)the National Natural Science Foundation of China(Grant Nos.62271305 and 62001287).
文摘We propose a joint look-up-table(LUT)-based nonlinear predistortion and digital resolution enhancement scheme to achieve high-speed and low-cost optical interconnects using low-resolution digital-to-analog converters(DACs).The LUT-based predistortion is employed to mitigate the patterndependent effect(PDE)of a semiconductor optical amplifier(SOA),while the digital resolution enhancer(DRE)is utilized to shape the quantization noise,lowering the requirement for the resolution of DAC.We experimentally demonstrate O-band intensity modulation and direct detection(IM/DD)transmission of 124-GBd 4∕6-level pulse-amplitude modulation ePAMT-4∕6 and 112-GBd PAM-8 signals over a 2-km standard single-mode fiber(SSMF)with 3∕3.5∕4-bit DACs.In the case of 40-km SSMF transmission with an SOAbased preamplifier,124-GBd on-off-keying(OOK)/PAM-3/PAM-4 signals are successfully transmitted with 1.5∕2∕3-bit DACs.To the best of our knowledge,we have achieved the highest net data rates of 235.3-Gb∕s PAM-4,289.7-Gb∕s PAM-6,and 294.7 Gb∕s PAM-8 signals over 2-km SSMF,as well as 117.6-Gb∕s OOK,173.8-Gb∕s PAM-3,and−231.8 Gb∕s PAM-4 signals over 40-km SSMF,employing low-resolution DACs.The experimental results reveal that the joint LUT-based predistortion and DRE effectively mitigate the PDE and improve the signal-to-quantization noise ratio by shaping the noise.The proposed scheme can provide a powerful solution for low-cost IM/DD optical interconnects beyond 200 Gb∕s.
基金Project supported by the "Shuang Bai Plan" and "Shenzhen-Hong Kong Innovation Circle" Research Program of Shenzhen,China
文摘We propose a robust digital watermarking algorithm for copyright protection.A stable feature is obtained by utilizing QR factorization and discrete cosine transform(DCT) techniques,and a meaningful watermark image is embedded into an image by modifying the stable feature with a quantization index modulation(QIM) method.The combination of QR factorization,DCT,and QIM techniques guarantees the robustness of the algorithm.Furthermore,an embedding location selection method is exploited to select blocks with small modifications as the embedding locations.This can minimize the embedding distortion and greatly improve the imperceptibility of our scheme.Several standard images were tested and the experimental results were compared with those of other published schemes.The results demonstrate that our proposed scheme can achieve not only better imperceptibility,but also stronger robustness against common signal processing operations and lossy compressions,such as filtering,noise addition,scaling,sharpening,rotation,cropping,and JPEG/JPEG2000 compression.
基金This work was supported by the National Natural Science Foundation of China(No.61379151,61401512,61572052,U1636219)the National Key Research and Development Program of China(No.2016YFB0801303,2016QY01W0105)the Key Technologies Research and Development Program of Henan Provinces(No.162102210032).
文摘In view of the fact that the current adaptive steganography algorithms are difficult to resist scaling attacks and that a method resisting scaling attack is only for the nearest neighbor interpolation method,this paper proposes an image steganography algorithm based on quantization index modulation resisting both scaling attacks and statistical detection.For the spatial image,this paper uses the watermarking algorithm based on quantization index modulation to extract the embedded domain.Then construct the embedding distortion function of the new embedded domain based on S-UNIWARD steganography,and use the minimum distortion coding to realize the embedding of the secret messages.Finally,according to the embedding modification amplitude of secret messages in the new embedded domain,the quantization index modulation algorithm is applied to realize the final embedding of secret messages in the original embedded domain.The experimental results show that the algorithm proposed is robust to the three common interpolation attacks including the nearest neighbor interpolation,the bilinear interpolation and the bicubic interpolation.And the average correct extraction rate of embedded messages increases from 50%to over 93% after 0.5 times-fold scaling attack using the bicubic interpolation method,compared with the classical steganography algorithm S-UNIWARD.Also the algorithm proposed has higher detection resistance than the original watermarking algorithm based on quantization index modulation.
基金supported in part by the National Natural Science Foundation of China (61902149,61932010 and 62032009)the Natural Science Foundation of Guangdong Province (2020A1515010393).
文摘Data hiding plays an important role in privacy protection and authentication,but most data hiding methods fail to achieve satisfactory performance in resisting scaling attacks and additive attacks.To this end,this paper proposes a new quantization index modulation(QIM)variant based on division domains(D-QIM).It can not only resist the above two attacks well,but also adjust the performance trade-offs by controlling the parameters.Simulation results confirm the performance gain of D-QIM in terms of the bit error rate(BER).
文摘基于MLAT多点定位的A-SMGCS系统可显著提高机场场面监视的精度。对机场场面监视雷达中数据采集系统的设计方法进行详细地阐述。利用高速A/D实时采集对数放大器输出的回波数据,经F P G A处理后,通过光纤发送至信号处理。实际工作结果表明,该设计方案成熟、可靠,为类似的系统或项目提供一个有益的借鉴。
