In order to eliminate float-point operations for fast wavelet transform, an integer D9/7 biorthogonal reversible wavelet transform was accomplished by lifting scheme. The lifting scheme based wavelet transform can be ...In order to eliminate float-point operations for fast wavelet transform, an integer D9/7 biorthogonal reversible wavelet transform was accomplished by lifting scheme. The lifting scheme based wavelet transform can be finished by addition and shift simply. It improved the quality of reconstructive image and greatly reduced the computational complexity due to integer operation. It is suitable for real-time image coding on hardware such as DSP. The simulation results show that the lifting scheme based SPIHT is prior to traditional wavelet based SPHIT in quality and complexity.展开更多
针对多级树集合分裂算法(Set Partitioning In H ierarchical Tree,SPIHT)复杂的特点,采用整数实现的提升格式代替了原来的小波变换,简化了计算过程。对小波系数采用基于块的结构划分,在频域重新建立空间方向树。根据块中相邻系数相关...针对多级树集合分裂算法(Set Partitioning In H ierarchical Tree,SPIHT)复杂的特点,采用整数实现的提升格式代替了原来的小波变换,简化了计算过程。对小波系数采用基于块的结构划分,在频域重新建立空间方向树。根据块中相邻系数相关性建立上下文模型,对输出信息进行自适应算术编码,提高了编码效率。实验表明,在相同的比特率条件下。展开更多
针对SPIHT(set partitioning in hierarchical trees)算法的编码过程具有重复运算、存储量大等问题,提出了一种适合于DSP(digital signal processors)处理的低内存并行SPIHT算法。该算法采用乒乓缓存策略,使得数据的传输和编码能够同时...针对SPIHT(set partitioning in hierarchical trees)算法的编码过程具有重复运算、存储量大等问题,提出了一种适合于DSP(digital signal processors)处理的低内存并行SPIHT算法。该算法采用乒乓缓存策略,使得数据的传输和编码能够同时进行。通过引入基于行的整型提升方案,使得只需经少量行变换就能进行列变换,提高了小波的变换速度。根据DSP的并行特性和SPIHT算法的缺点,采用“改进的最大幅值求取方法”、“误差位数以及绝对零值和绝对零集合”、“最大值与零值图”和“单棵零树编码”等多种方法对其进行了改进,大大缓解了对内存的压力,减少了算法的运算量。该算法与LZC(listless zerotree coding)算法相比,重构图像的峰值信噪比相当,但速度提高了2倍,能满足一般的实时压缩要求。展开更多
Aiming at shortage of the SPIHT algorithm, an improved image compression algorithm is proposed, in order to overcome the shortcomings of decoding image quality and coding time, LS9/7 lifting wavelet transform is adopt...Aiming at shortage of the SPIHT algorithm, an improved image compression algorithm is proposed, in order to overcome the shortcomings of decoding image quality and coding time, LS9/7 lifting wavelet transform is adopted. According to the characteristics of the human visual system (HVS), the scanning mode and the method to determine the threshold of algorithm are changed to improve the quality of reconstruction image. On the question of repeating scan of SPIHT algorithm, using maximum list thought, greatly reduce the computation and save operating time. The experimental results have proved that the improved algorithm of image decoding time and the quality of reconstruction images are better than the original algorithm , especially in the case of low bit rate.展开更多
弹载图像压缩系统要求压缩算法在保证图像质量的前提下对图像实现大压缩比实时压缩。针对这些要求,提出了采用小波编码算法作为图像压缩系统的实现算法和DSP作为算法的实现平台。小波压缩算法分为两个部分,即先对图像进行整型提升小波变...弹载图像压缩系统要求压缩算法在保证图像质量的前提下对图像实现大压缩比实时压缩。针对这些要求,提出了采用小波编码算法作为图像压缩系统的实现算法和DSP作为算法的实现平台。小波压缩算法分为两个部分,即先对图像进行整型提升小波变换,再利用SPIHT(Set Partitioning in Hierarchical Trees)算法对变换结果进行编码。对小波编码过程中存在重复运算和存储量大的缺点进行了改进,使之适合于DSP并行处理。实验结果表明,改进的算法与原算法相比,重构图像的峰值信噪比相当,大于28dB,满足图像质量要求;图像压缩速度达到20帧/s,完全满足实时性要求。展开更多
基金The Ministerial Level Advanced Research Foundation
文摘In order to eliminate float-point operations for fast wavelet transform, an integer D9/7 biorthogonal reversible wavelet transform was accomplished by lifting scheme. The lifting scheme based wavelet transform can be finished by addition and shift simply. It improved the quality of reconstructive image and greatly reduced the computational complexity due to integer operation. It is suitable for real-time image coding on hardware such as DSP. The simulation results show that the lifting scheme based SPIHT is prior to traditional wavelet based SPHIT in quality and complexity.
文摘针对多级树集合分裂算法(Set Partitioning In H ierarchical Tree,SPIHT)复杂的特点,采用整数实现的提升格式代替了原来的小波变换,简化了计算过程。对小波系数采用基于块的结构划分,在频域重新建立空间方向树。根据块中相邻系数相关性建立上下文模型,对输出信息进行自适应算术编码,提高了编码效率。实验表明,在相同的比特率条件下。
文摘针对SPIHT(set partitioning in hierarchical trees)算法的编码过程具有重复运算、存储量大等问题,提出了一种适合于DSP(digital signal processors)处理的低内存并行SPIHT算法。该算法采用乒乓缓存策略,使得数据的传输和编码能够同时进行。通过引入基于行的整型提升方案,使得只需经少量行变换就能进行列变换,提高了小波的变换速度。根据DSP的并行特性和SPIHT算法的缺点,采用“改进的最大幅值求取方法”、“误差位数以及绝对零值和绝对零集合”、“最大值与零值图”和“单棵零树编码”等多种方法对其进行了改进,大大缓解了对内存的压力,减少了算法的运算量。该算法与LZC(listless zerotree coding)算法相比,重构图像的峰值信噪比相当,但速度提高了2倍,能满足一般的实时压缩要求。
文摘Aiming at shortage of the SPIHT algorithm, an improved image compression algorithm is proposed, in order to overcome the shortcomings of decoding image quality and coding time, LS9/7 lifting wavelet transform is adopted. According to the characteristics of the human visual system (HVS), the scanning mode and the method to determine the threshold of algorithm are changed to improve the quality of reconstruction image. On the question of repeating scan of SPIHT algorithm, using maximum list thought, greatly reduce the computation and save operating time. The experimental results have proved that the improved algorithm of image decoding time and the quality of reconstruction images are better than the original algorithm , especially in the case of low bit rate.
文摘弹载图像压缩系统要求压缩算法在保证图像质量的前提下对图像实现大压缩比实时压缩。针对这些要求,提出了采用小波编码算法作为图像压缩系统的实现算法和DSP作为算法的实现平台。小波压缩算法分为两个部分,即先对图像进行整型提升小波变换,再利用SPIHT(Set Partitioning in Hierarchical Trees)算法对变换结果进行编码。对小波编码过程中存在重复运算和存储量大的缺点进行了改进,使之适合于DSP并行处理。实验结果表明,改进的算法与原算法相比,重构图像的峰值信噪比相当,大于28dB,满足图像质量要求;图像压缩速度达到20帧/s,完全满足实时性要求。
