With the advances of display technology, three-dimensional(3-D) imaging systems are becoming increasingly popular. One way of stimulating 3-D perception is to use stereo pairs, a pair of images of the same scene acqui...With the advances of display technology, three-dimensional(3-D) imaging systems are becoming increasingly popular. One way of stimulating 3-D perception is to use stereo pairs, a pair of images of the same scene acquired from different perspectives. Since there is an inherent redundancy between the images of a stereo pairs, data compression algorithms should be employed to represent stereo pairs efficiently. The proposed techniques generally use block-based disparity compensation. In order to get the higher compression ratio, this paper employs the wavelet-based mixed-resolution coding technique to incorporate with SPT-based disparity-compensation to compress the stereo image data. The mixed-resolution coding is a perceptually justified technique that is achieved by presenting one eye with a low-resolution image and the other with a high-resolution image. Psychophysical experiments show that the stereo image pairs with one high-resolution image and one low-resolution image provide almost the same stereo depth to that of a stereo image with two high-resolution images. By combining the mixed-resolution coding and SPT-based disparity-compensation techniques, one reference (left) high-resolution image can be compressed by a hierarchical wavelet transform followed by vector quantization and Huffman encoder. After two level wavelet decompositions, for the low-resolution right image and low-resolution left image, subspace projection technique using the fixed block size disparity compensation estimation is used. At the decoder, the low-resolution right subimage is estimated using the disparity from the low-resolution left subimage. A full-size reconstruction is obtained by upsampling a factor of 4 and reconstructing with the synthesis low pass filter. Finally, experimental results are presented, which show that our scheme achieves a PSNR gain (about 0.92dB) as compared to the current block-based disparity compensation coding techniques.展开更多
目的提出了一种彩色图像数字水印技术,解决数字水印在大数据量水印、不可见性和鲁棒性之间的关系。方法该算法对彩色QR码水印和彩色载体图像分别进行RGB三通道分解,彩色水印单通图像进行混沌加密;对彩色载体单通道图像进行Contourlet变...目的提出了一种彩色图像数字水印技术,解决数字水印在大数据量水印、不可见性和鲁棒性之间的关系。方法该算法对彩色QR码水印和彩色载体图像分别进行RGB三通道分解,彩色水印单通图像进行混沌加密;对彩色载体单通道图像进行Contourlet变换;按对应通道将水印嵌入到载体图像低频经奇异值分解后的对角矩阵。结果该算法在水印嵌入和提取仿真实验结果为PSNR>50 d B;鲁棒性仿真实验结果表明,该算法在抵抗任意旋转攻击和基本图像处理操作的攻击下,提取出来的彩色QR码颜色未失真,并且均能够成功解码和自动识别。结论该算法具有较强的鲁棒性和较好的不可见性,能够很好地将彩色水印嵌入彩色图像,可应用到实际的数字版权保护中。展开更多
为解决光在水下传播过程中由吸收与散射效应导致的水下图像模糊、对比度低和颜色失真问题,提出一种基于Inception-Residual和生成对抗网络的水下图像增强算法。首先,将退化水下图像缩放至256×256×3大小,以获得用于训练模型的...为解决光在水下传播过程中由吸收与散射效应导致的水下图像模糊、对比度低和颜色失真问题,提出一种基于Inception-Residual和生成对抗网络的水下图像增强算法。首先,将退化水下图像缩放至256×256×3大小,以获得用于训练模型的数据集。接着,将Inception模块、残差思想、编码解码结构和生成对抗网络相结合,构建IRGAN(Generative Adversarial Network with Inception-Residual)模型来增强水下图像。然后,利用全局相似性、内容感知和色彩感知构造多项损失函数,约束生成网络和判别网络的对抗训练。最后,通过训练好的模型对退化水下图像进行处理以获得清晰的水下图像。实验结果表明与现有增强方法相比,所提算法增强的水下图像在PSNR、UIQM和IE指标上的平均值分别比第二名提升13.6%、4.1%和0.9%。在主观感知和客观评估中,增强后的水下图像在清晰度、对比度增强和颜色校正方面均得到改善。展开更多
基金This project was supported by the National Natural Science Foundation (No. 69972027).
文摘With the advances of display technology, three-dimensional(3-D) imaging systems are becoming increasingly popular. One way of stimulating 3-D perception is to use stereo pairs, a pair of images of the same scene acquired from different perspectives. Since there is an inherent redundancy between the images of a stereo pairs, data compression algorithms should be employed to represent stereo pairs efficiently. The proposed techniques generally use block-based disparity compensation. In order to get the higher compression ratio, this paper employs the wavelet-based mixed-resolution coding technique to incorporate with SPT-based disparity-compensation to compress the stereo image data. The mixed-resolution coding is a perceptually justified technique that is achieved by presenting one eye with a low-resolution image and the other with a high-resolution image. Psychophysical experiments show that the stereo image pairs with one high-resolution image and one low-resolution image provide almost the same stereo depth to that of a stereo image with two high-resolution images. By combining the mixed-resolution coding and SPT-based disparity-compensation techniques, one reference (left) high-resolution image can be compressed by a hierarchical wavelet transform followed by vector quantization and Huffman encoder. After two level wavelet decompositions, for the low-resolution right image and low-resolution left image, subspace projection technique using the fixed block size disparity compensation estimation is used. At the decoder, the low-resolution right subimage is estimated using the disparity from the low-resolution left subimage. A full-size reconstruction is obtained by upsampling a factor of 4 and reconstructing with the synthesis low pass filter. Finally, experimental results are presented, which show that our scheme achieves a PSNR gain (about 0.92dB) as compared to the current block-based disparity compensation coding techniques.
文摘目的提出了一种彩色图像数字水印技术,解决数字水印在大数据量水印、不可见性和鲁棒性之间的关系。方法该算法对彩色QR码水印和彩色载体图像分别进行RGB三通道分解,彩色水印单通图像进行混沌加密;对彩色载体单通道图像进行Contourlet变换;按对应通道将水印嵌入到载体图像低频经奇异值分解后的对角矩阵。结果该算法在水印嵌入和提取仿真实验结果为PSNR>50 d B;鲁棒性仿真实验结果表明,该算法在抵抗任意旋转攻击和基本图像处理操作的攻击下,提取出来的彩色QR码颜色未失真,并且均能够成功解码和自动识别。结论该算法具有较强的鲁棒性和较好的不可见性,能够很好地将彩色水印嵌入彩色图像,可应用到实际的数字版权保护中。
文摘为解决光在水下传播过程中由吸收与散射效应导致的水下图像模糊、对比度低和颜色失真问题,提出一种基于Inception-Residual和生成对抗网络的水下图像增强算法。首先,将退化水下图像缩放至256×256×3大小,以获得用于训练模型的数据集。接着,将Inception模块、残差思想、编码解码结构和生成对抗网络相结合,构建IRGAN(Generative Adversarial Network with Inception-Residual)模型来增强水下图像。然后,利用全局相似性、内容感知和色彩感知构造多项损失函数,约束生成网络和判别网络的对抗训练。最后,通过训练好的模型对退化水下图像进行处理以获得清晰的水下图像。实验结果表明与现有增强方法相比,所提算法增强的水下图像在PSNR、UIQM和IE指标上的平均值分别比第二名提升13.6%、4.1%和0.9%。在主观感知和客观评估中,增强后的水下图像在清晰度、对比度增强和颜色校正方面均得到改善。
