针对车载视频图像中同时包含局部运动模糊和全局运动模糊,现有去模糊算法难以适用且效果差等问题,提出一种基于再模糊理论的复杂车载模糊图像复原方法。根据车载视频图像的特点把图像分割为车身和非车身区域,采用改进后的模糊参数估计算...针对车载视频图像中同时包含局部运动模糊和全局运动模糊,现有去模糊算法难以适用且效果差等问题,提出一种基于再模糊理论的复杂车载模糊图像复原方法。根据车载视频图像的特点把图像分割为车身和非车身区域,采用改进后的模糊参数估计算法,在车身区域图像块估算出的全局运动模糊参数,对整幅图像进行全局模糊恢复;对复原前后的非车身图像进行分块处理,利用复原前后图像块结构相似度(Structural Similarity,SSIM)和局部均方差的差异性,检测和提取出局部模糊区域;对提取的模糊区域进行复原后与清晰区域拼接融合,合成清晰的图像。与现有算法对比实验分析,所提算法取得了不错的效果,且复原后图像的峰值信噪比(Peak Signal to Noise Ratio,PSNR)和SSIM表现良好。展开更多
Hyperspectral images (HSI) have hundreds of bands, which impose heavy burden on data storage and transmission bandwidth. Quite a few compression techniques have been explored for HSI in the past decades. One high perf...Hyperspectral images (HSI) have hundreds of bands, which impose heavy burden on data storage and transmission bandwidth. Quite a few compression techniques have been explored for HSI in the past decades. One high performing technique is the combination of principal component analysis (PCA) and JPEG-2000 (J2K). However, since there are several new compression codecs developed after J2K in the past 15 years, it is worthwhile to revisit this research area and investigate if there are better techniques for HSI compression. In this paper, we present some new results in HSI compression. We aim at perceptually lossless compression of HSI. Perceptually lossless means that the decompressed HSI data cube has a performance metric near 40 dBs in terms of peak-signal-to-noise ratio (PSNR) or human visual system (HVS) based metrics. The key idea is to compare several combinations of PCA and video/ image codecs. Three representative HSI data cubes were used in our studies. Four video/image codecs, including J2K, X264, X265, and Daala, have been investigated and four performance metrics were used in our comparative studies. Moreover, some alternative techniques such as video, split band, and PCA only approaches were also compared. It was observed that the combination of PCA and X264 yielded the best performance in terms of compression performance and computational complexity. In some cases, the PCA + X264 combination achieved more than 3 dBs than the PCA + J2K combination.展开更多
为了在去除高斯噪声的同时更有效地保持图像的边缘和细节,提出了信噪局部方差自适应的小波滤波方法.根据图像与高斯噪声的小波系数的分布特征,提出了一种信噪局部方差自适应的阈值.同时,鉴于无噪图像的小波系数具有平滑连贯性,提出一种...为了在去除高斯噪声的同时更有效地保持图像的边缘和细节,提出了信噪局部方差自适应的小波滤波方法.根据图像与高斯噪声的小波系数的分布特征,提出了一种信噪局部方差自适应的阈值.同时,鉴于无噪图像的小波系数具有平滑连贯性,提出一种连续的、可微的且无限逼近原小波系数的阈值函数.阈值依据信噪强度对信号系数与噪声系数进行区分,阈值函数依据阈值对小波系数进行量化处理,以去除噪声.实验结果表明,所提出的方法对图像去噪所得的PSNR(peak signal to noise ratio)和SSIM(structural similarity index)值以及图像的视觉效果,相对于现有的小波去噪方法有较大的提升,在彻底去除高斯噪声同时,更有效地保持图像的边缘和细节.展开更多
文摘针对车载视频图像中同时包含局部运动模糊和全局运动模糊,现有去模糊算法难以适用且效果差等问题,提出一种基于再模糊理论的复杂车载模糊图像复原方法。根据车载视频图像的特点把图像分割为车身和非车身区域,采用改进后的模糊参数估计算法,在车身区域图像块估算出的全局运动模糊参数,对整幅图像进行全局模糊恢复;对复原前后的非车身图像进行分块处理,利用复原前后图像块结构相似度(Structural Similarity,SSIM)和局部均方差的差异性,检测和提取出局部模糊区域;对提取的模糊区域进行复原后与清晰区域拼接融合,合成清晰的图像。与现有算法对比实验分析,所提算法取得了不错的效果,且复原后图像的峰值信噪比(Peak Signal to Noise Ratio,PSNR)和SSIM表现良好。
文摘Hyperspectral images (HSI) have hundreds of bands, which impose heavy burden on data storage and transmission bandwidth. Quite a few compression techniques have been explored for HSI in the past decades. One high performing technique is the combination of principal component analysis (PCA) and JPEG-2000 (J2K). However, since there are several new compression codecs developed after J2K in the past 15 years, it is worthwhile to revisit this research area and investigate if there are better techniques for HSI compression. In this paper, we present some new results in HSI compression. We aim at perceptually lossless compression of HSI. Perceptually lossless means that the decompressed HSI data cube has a performance metric near 40 dBs in terms of peak-signal-to-noise ratio (PSNR) or human visual system (HVS) based metrics. The key idea is to compare several combinations of PCA and video/ image codecs. Three representative HSI data cubes were used in our studies. Four video/image codecs, including J2K, X264, X265, and Daala, have been investigated and four performance metrics were used in our comparative studies. Moreover, some alternative techniques such as video, split band, and PCA only approaches were also compared. It was observed that the combination of PCA and X264 yielded the best performance in terms of compression performance and computational complexity. In some cases, the PCA + X264 combination achieved more than 3 dBs than the PCA + J2K combination.
文摘为了在去除高斯噪声的同时更有效地保持图像的边缘和细节,提出了信噪局部方差自适应的小波滤波方法.根据图像与高斯噪声的小波系数的分布特征,提出了一种信噪局部方差自适应的阈值.同时,鉴于无噪图像的小波系数具有平滑连贯性,提出一种连续的、可微的且无限逼近原小波系数的阈值函数.阈值依据信噪强度对信号系数与噪声系数进行区分,阈值函数依据阈值对小波系数进行量化处理,以去除噪声.实验结果表明,所提出的方法对图像去噪所得的PSNR(peak signal to noise ratio)和SSIM(structural similarity index)值以及图像的视觉效果,相对于现有的小波去噪方法有较大的提升,在彻底去除高斯噪声同时,更有效地保持图像的边缘和细节.
