首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 313 毫秒
1.
为了解决基本分形图像编码算法中的编码过程特别耗时问题,通过定义每个range块和domain块的相似比,建立它与匹配均方根误差间的关系不等式,可把寻找range块的最佳匹配domain块的全局搜索变为近邻搜索.鉴于在自仿射变换下最优匹配块间的相似比值应该接近,但它们间的远近程度不一致,因此,每个range块的最优匹配块搜索范围应限制在与其相似比值接近的domain块变邻域内.四幅图像的仿真结果表明,它确实能够在PSNR降低0.103d B(其结构相似性SSIM值仅下降0.0004)的情况下,平均耗时仅为基本分形编码算法的38.97%左右,而且也优于可选特征算法,实现了加快编码过程速度的目标.  相似文献   

2.
为了解决全搜索分形图像编码算法在编码过程中range块和domain块匹配特别耗时问题,定义了每个range块和domain块的自相似特征,由于在自仿射变换下最优匹配块间的自相似特征应该接近,因此,每个range块的最优匹配块搜索范围仅限在与其自相似特征接近的domain块邻域内,变全局搜索为局部搜索.六幅图像的仿真结果表明,它确实能够在PSNR降低0.48d B(其结构相似性SSIM值仅下降0.0015)的情况下,平均耗时仅为全搜索分形编码算法的18.65%左右,而且也优于其他特征算法,所提算法达到了加快编码过程速度的目标.  相似文献   

3.
虽然分形图像压缩技术在高压缩比时具有高的重建图像质量,但是它编码过程耗时长导致了它难以在图像压缩领域广泛应用.为了减少寻找range块的最佳匹配domain块的时间,本文提出了基于方差剔除条件的分形编码方法,它利用均方根误差和方差关系的不等式,设置一个range块与domain块匹配搜索的提早结束条件来避免全搜索,从而减少编码过程的时间,实现加快编码速度的目的.计算机仿真显示,对5幅复杂性不同的测试图像,在影响解码图像主观质量很小的情况下,本文方案加快了基本分形编码算法的编码速度27倍.  相似文献   

4.
在数字视频压缩编码技术中,为了消除视频序列相邻帧之间的数据冗余,对最小平均绝对误差匹配方法和平滑约束的最小平均绝对误差块匹配算法进行了改进,提出了一种基于整数变换,具有平滑约束的块匹配算法,重新设计了平滑约束条件,提出了新的搜索匹配函数,并进行了仿真实验.实验结果表明,该方法可有效降低匹配块的搜索点数,提升了峰值信噪比,降低了编码比特数.  相似文献   

5.
针对现有块分割压缩感知(block compressive sensing,BCS)算法的块效应问题,提出一种低复杂度、可消除块效应的新型块分割重构算法.在稀疏表达时,采用小波变换(DWT)代替离散余弦变换(DCT),改善图像细节分量;在测量时,依据分块图像频率特征对测量矩阵加权,提高图像质量;在重构时,采用正交匹配追踪(orthogonal matching pursuit,OMP)算法代替匹配追踪(matching pursuit,MP)算法,提高重构速度.仿真结果表明,所提出的算法可在保证重构速度的情况下,有效消除块效应,且不增加内存占用.  相似文献   

6.
为提高编码效率,从运动估计匹配法则的特性分析出发,提出一种基于MSE匹配法则的全零块判决算法.在保持编码质量的前提下,推荐算法能够有效地提高运动估计的速度并减少DCT和量化的运算量.MPEG-4下的实验表明,改进的判决条件能够检测出高达92.6 %的全零块;推荐算法比常规算法最大能节省65.7 %的整体编码时间.  相似文献   

7.
针对分形图像压缩算法编码时间较长的问题,提出了一种基于迭代控制搜索策略的快速分形图像压缩(ICSS)算法.当值域块寻找匹配的定义域块时,通过分形码的迭代更新次数来控制搜索过程,设置搜索终止条件,去除搜索过程中的低效搜索和无效搜索;同时计算图像块相似度时采用等距采样图像进行降维处理,进一步降低计算复杂度.实验结果表明:与经典算法文献算法相比,本文算法在保持图像压缩比不变的情况下,能获得更好的重建图像质量,且编码速度显著提升.  相似文献   

8.
提出一种基于Gabor匹配的甚低比特视频编码算法 ,通过算法自学习优化Gabor匹配集提高编码效率 .实验测试结果表明 ,在甚低码率 ( 2 4kb/s和 10kb/s)下有效保证视频编码PSNR和编码效率 ,同时从根本上解决传统编码方法在甚低码率视频编码中的块效应问题 .  相似文献   

9.
AVS-M标准是中国最近自主制订的数字音视频编码系列标准(AVS)中的第七部分:移动视频编码标准.根据AVS-M视频编码标准的新特点,对其中的全零块检测阈值进行了推导,提出了一种基于全零块检测的运动搜索提前终止准则.针对AVS-M的多编码模式,进一步将全零块检测用于AVS-M中多种编码模式的选择,有效地提高了运动估计的效率.实验结果表明,该方法在保持AVS-M编码器编码性能的同时,可显著提高编码器的编码速度.  相似文献   

10.
一种快速分形图像编码方法   总被引:2,自引:1,他引:2  
提出了一种快速分形图像编码方法.该方法利用原图像的均值图像设计编码码书,利用高阶统计量对域块进行分类,可以有效地减少域池中域块之间的相关性.同时,使用遗传算法搜索值块的匹配域块,可以减少分形图像编码时值块与域块的匹配搜索时间,加快图像分形编码的速度.基于这种方法的分形图像编码,在图像解码时不需要迭代,可以提高图像的解码速度,不需要对编码时的伸缩系数加以限制.仿真结果表明,这种快速分形编码方法可以减小图像编码时间,较大提高了分形编码的速度.在相同压缩比的情况下,解码图像的质量也比传统方法要高.  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

15.
Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.  相似文献   

16.
以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.  相似文献   

17.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

18.
Quality traits in wheat (Triticum aestirum L.) were studied by quantitative trait locus (QTL) analysis in a recombinant inbred line (RIL) population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross (ChSh). Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.  相似文献   

19.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

20.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号