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1.
为了探讨高频喷射通气(HFJV)治疗海水淹溺肺水肿(PE-SWD)的作用机理,采用全自动血气酸碱分析仪和计算机图像分析系统对海水淹溺肺水肿组(PE-SWD-G)、高频喷射通气组(HFJV-G)和正常对照组(ONTROL GROPU,cg)兔PaO2、PaCO2血氧饱和度(SaO2和兔肺内Na^+-K^+-ATPase进行自动检测和定量分析。结果表明,PE-SWD经HFJV治疗100min,HFJV  相似文献   

2.
THEUSINGOTHELIGHTWORKSHOPAPPARATUSINHANDINJURIESTHEUSINGOTHELIGHTWORKSHOPAPPARATUSINHANDINJURIESWangCuilan;HangMinqi;ShiJian;...  相似文献   

3.
THEUSINGOFLEATHERSTRAPINREHABILITATIONOFPIPJOINTTHEUSINGOFLEATHERSTRAPINREHABILITATIONOFPIPJOINTshiJian;LiuLingtu;HuangMinqi;...  相似文献   

4.
LIGHTSCATTERINGPROPERTYOFHUMANBLOODATTHEWAVELENGTHOF810NMLIGHTSCATTERINGPROPERTYOFHUMANBLOODATTHEWAVELENGTHOF810NMJianZhong;D...  相似文献   

5.
ASTUDYONTHEPARAWALKERCONTROLLEDBYEMGASTUDYONTHEPARAWALKERCONTROLLEDBYEMGWangRencheng;ZhangPeiyu;ZhangJichuan;JinDewen(Dept.of...  相似文献   

6.
DESIGNOFANASYMMETRYACTIVETRAPFILTERDESIGNOFANASYMMETRYACTIVETRAPFILTERJiangZongyi(JinglingHospital,Naming,210002,China)ABSTRA...  相似文献   

7.
THESTATUSANDTRENDOFLAPAROSCOPICSURGERYINCHINATHESTATUSANDTRENDOFLAPAROSCOPICSURGERYINCHINAGaoYi;YangJi-Zhen(DepartmentofSurge...  相似文献   

8.
用伪-维格讷(Pseudo-wigner)分布量化噪声MRS信号〔英]/LeclercJHJ//IEEETransBME.-1994,41(9).-809本文讨论用Pseudo-wlgner分布(PWD)估计在量化振幅衰减的正弦信号过程中噪声引起的误...  相似文献   

9.
将人单核细胞趋化蛋白-1(MCP-1)的cDNA插入融合蛋白表达载体pGEX-4T-1中,构建成质粒pGEX/MCP转化大肠杆菌JM109,经IPTG诱导后合成GST-MCP-1融合蛋白。用12%SDS-PAGE检测在30kD左右有新生蛋白条带出现,表达量约占菌体总蛋白的31.7%。趋化实验证明,该产物具备明确的单核细胞趋化活性。  相似文献   

10.
TREATMENTOFFULMINANTLIVERFAILUREWISTARRATSWITHIMPLANTEDARTIFICIALCELLSMICROENCAPSULATEDLIVINGHEPATOCYTESSongJichang,LiTao,XuJ...  相似文献   

11.
This work demonstrates the image qualities between two popular JPEG2000 programs. Two medical image compression algorithms are both coded using JPEG2000, but they are different regarding the interface, convenience, speed of computation, and their characteristic options influenced by the encoder, quantization, tiling, etc. The differences in image quality and compression ratio are also affected by the modality and compression algorithm implementation. Do they provide the same quality? The qualities of compressed medical images from two image compression programs named Apollo and JJ2000 were evaluated extensively using objective metrics. These algorithms were applied to three medical image modalities at various compression ratios ranging from 10:1 to 100:1. Following that, the quality of the reconstructed images was evaluated using five objective metrics. The Spearman rank correlation coefficients were measured under every metric in the two programs. We found that JJ2000 and Apollo exhibited indistinguishable image quality for all images evaluated using the above five metrics (r > 0.98, p < 0.001). It can be concluded that the image quality of the JJ2000 and Apollo algorithms is statistically equivalent for medical image compression.  相似文献   

12.
基于JPEG技术的CT图像压缩方法的研究   总被引:1,自引:0,他引:1  
CT图像在医学影像诊断中占有重要地位,CT图像压缩技术是PACS系统的重要组成部分。JPEG静止图像压缩标准目前已成为一种广泛应用的图像压缩技术。JPEG充分利用人眼的视觉特性,对DCT系数的低频系数进行细量化,而对高频系数进行粗量化,但未对图像的边缘特征进行特殊的处理。而图像的部分边缘特征又正是隐含于DCT高频系数中。文中从图像边缘信息的谱分析入手,通过理论推导及实例分析得到平直单边缘图像子块其DCT系数能量的分布规律,并以此为理论基础设计出JPEG中DCT系数量化表(Q表),实验结果表明该Q表对非平直边缘图象子块没有影响,而对含有平直边缘图像子块的边缘信息进行了有效的保持。  相似文献   

13.
Fidler A  Skaleric U  Likar B 《Medical physics》2006,33(8):2832-2838
The aim of the study was to demonstrate and critically discuss the influence of image information on compressibility and image degradation. The influence of image information on image compression was demonstrated on the axial computed tomography images of a head. The standard Joint Photographic Expert Group (JPEG) and JPEG 2000 compression methods were used in compression ratio (CR) and in quality factor (QF) compression modes. Image information was estimated by calculating image entropy, while the effects of image compression were evaluated quantitatively, by file size reduction and by local and global mean square error (MSE), and qualitatively, by visual perception of distortion in high and low contrast test patterns. In QF compression mode, a strong correlation between image entropy and file size was found for JPEG (r=0.87, p < 0.001) and JPEG 2000 (r=0.84, p < 0.001), while corresponding local MSE was constant (4.54) or nearly constant (2.36-2.37), respectively. For JPEG 2000 CR compression mode, CR was nearly constant (1:25), while local MSE varied considerably (2.26 and 10.09). The obtained qualitative and quantitative results clearly demonstrate that image degradation highly depends on image information, which indicates that the degree of image degradation cannot be guaranteed in CR but only in QF compression mode. CR is therefore not a measure of choice for expressing the degree of image degradation in medical image compression. Moreover, even when using QF compression modes, objective evaluation, and comparison of the compression methods within and between studies is often not possible due to the lack of standardization of compression quality scales.  相似文献   

14.
The investigation results for improving lossy compression techniques for ultrasound and angio images are presented. The goal was to determine where the compression process could be improved for the medical application, and to make efforts to improve it. It is proved that the wavelet transform outperforms the discrete cosine transform applied to ultrasound and angio images. A lot of wavelet classes were tried for choosing the best one suited for corresponding image classes, which were characterised by a content complexity criterion. The analysis of international image compression standards was carried out. Special attention was paid to an algorithmical and high level service structure of a new still image compression standard JPEG2000. Its open architecture enables including some wavelet classes which we would like to suggest for medical images. A set of recommendations for acceptable compression ratio for different medical image modalities was developed. It was carried out on the base of compression study performed by the group of angiologists and cardiologists.  相似文献   

15.
由于医学图像所包含的数据量巨大,不利于存储和在现有网络上有效地传输,本研究使用VC++实现基于联合图像专家组2000(Joint Photographic Experts Group2000,JPEG2000)图像压缩算法对医学图像进行处理,根据医学数字图像通讯(Digital Imaging and Communicationin Medicine,DICOM)标准中存储服务的规则实现医学图像的存储服务。研究结果表明,使用JPEG2000压缩算法处理后的医学图像,不仅能大大节约存储空间,而且能降低传输时所需要的带宽。因此,JPEG2000压缩算法在DICOM推广及远程医疗的发展中具有积极意义。  相似文献   

16.
With ever increasing use of medical ultrasound (US) images, a challenge exists to deal with storage and transmission of these images while still maintaining high diagnostic quality. In this article, a state-of-the-art context based method is proposed to overcome this challenge called contextual vector quantization (CVQ). In this method, a contextual region is defined as a region containing the most important information and must be encoded without considerable quality loss. Attempts are made to encode this region with high priority and high resolution (low compression ratio and high bit rate) CVQ algorithm; and the background, which has a lower priority, is separately encoded with a low resolution (high compression ratio and low bit rate) version of the CVQ algorithm. Finally both of the encoded contextual region and the encoded background region is merged together to reconstruct the output image. As a result, very good diagnostic image quality with lower image size and enhanced performance parameters including mean square error (MSE), pick signal to noise ratio (PSNR) and coefficient of correlation (CoC) are gained. The experimental results show that the proposed CVQ methodology is superior as compared to other existing methods (general methods such as JPEG and JPEG2K, and ROI based methods such as EBCOT and CSPIHT) in terms of measured performance parameters. This makes CVQ compression method a feasible technique to overcome storage and transmission limitations.  相似文献   

17.
In this paper, an efficient technique for compression of medical ultrasound (US) images is proposed. The technique is based on wavelet transform of the original image combined with vector quantization (VQ) of high-energy subbands using the LBG algorithm. First, we analyse the statistical behaviour of wavelet coefficients in US images across various subbands and scales. The analysis show that most of the image energy is concentrated in one of the detail subband, either in the vertical detail subband (most of the time) or in the horizontal subband. The other two subbands at each decomposition level contribute negligibly to the total image energy. Then, by exploiting this statistical analysis, a low-complexity image coder is designed, which applies VQ only to the highest energy subband while discarding the other detail subbands at each level of decomposition. The coder is tested on a series of abdominal and uterus greyscale US images. The experimental results indicate that the proposed method clearly outperforms the JPEG2000 (Joint Photographers Expert Group) encoder both qualitatively and quantitatively. For example, without using any entropy coder, the proposed method yields a peak signal to noise ratio gain of 0.2 dB to 1.2 dB over JPEG2000 on medical US images.  相似文献   

18.
This presentation focuses on the quantitative comparison of three lossy compression methods applied to a variety of 12-bit medical images. One Joint Photographic Exports Group (JPEG) and two wavelet algorithms were used on a population of 60 images. The medical images were obtained in Digital Imaging and Communications in Medicine (DICOM) file format and ranged in matrix size from 256 × 256 (magnetic resonance [MR]) to 2,560 × 2,048 (computed radiography [CR], digital radiography [DR], etc). The algorithms were applied to each image at multiple levels of compression such that comparable compressed file sizes were obtained at each level. Each compressed image was then decompressed and quantitative analysis was performed to compare each compressed-thendecompressed image with its corresponding original image. The statistical measures computed were sum of absolute differences, sum of squared differences, and peak signal-to-noise ratio (PSNR). Our results verify other research studies which show that wavelet compression yields better compression quality at constant compressed file sizes compared with JPEG. The DICOM standard does not yet include wavelet as a recognized lossy compression standard. For implementers and users to adopt wavelet technology as part of their image management and communication installations, there has to be significant differences in quality and compressibility compared with JPEG to justify expensive software licenses and the introduction of proprietary elements in the standard. Our study shows that different wavelet implementations vary in their capacity to differentiate themselves from the old, established lossy JPEG.  相似文献   

19.
In this article, three novel lossless image compression schemes, hybrid predictive/vector quantization lossless image coding (HPVQ), shape-adaptive differential pulse code modulation (DPCM) (SADPCM), and shape-VQ-based hybrid ADPCM/DCT (ADPCMDCT) are introduced. All are based on the lossy coder, VQ. However, VQ is used in these new schemes as a tool to improve the decorrelation efficiency of those traditional lossless predictive coders such as DPCM, adaptive DPCM (ADPCM), and multiplicative autoregressive coding (MAR). A new kind of VQ, shape-VQ, is also introduced in this article. It provides predictive coders useful information regarding the shape characters of image block. These enhance the performance of predictive coders in the context of lossless coding. Simulation results of the proposed coders applied in lossless medical image compression are presented. Some leading lossless techniques such as DPCM, hierarchical interfold (HINT), CALIC, and the standard lossless JPEG are included in the tests. Promising results show that all these three methods are good candidates for lossless medical image compression.  相似文献   

20.
探索基于小波变换对肺部CT图像进行无损雎缩的新方法.采用基于离散小波变换方法的JPEG2000标准对3019张肺部CT图像进行无损压缩,并针对压缩后图像效果进行统计分析.结果表明,该方法不但可以达到12.0的高压缩比,而且具有较高的图像尤损压缩质量,为临床CT医学影像的储存与诊断,提供了有益的技术与方法.  相似文献   

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