共查询到20条相似文献,搜索用时 49 毫秒
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对向传播神经网络(CPN)可以作为矢量量化器用于图像压缩,但CPN学习算法在进行码书设计时存在两个明显的缺陷。本文对CPN学习算法进行改进,提出了一种新的码书设计算法——快速竞争学习及误差修正算法(FCLECA)和一个基于改进CPN的快速矢量量化器模型,并讨论了FCLECA中的重要步骤和重要参数。仿真实验结果表明,FCLECA在生成高质量码书的同时大幅减少了训练时间,可以有效地实现快速矢量量化。 相似文献
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提出一种基于矢量量化技术的图象分形压缩编码方法,其能较好地克服传统的图象分形压缩编码方法中存在的速度慢,压缩率低等缺点,并且同时获得较高的图象恢复质量。 相似文献
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传统的矢量量化压缩算法将图像分割为相同大小的编码块,该方法存在较多的冗余.为了提高矢量量化压缩算法的效率,提出一种基于四叉树分割的变维矢量量化图像压缩算法.首先对8×8的图像块进行编码,计算各图像块绝对误差之和,若大于预设的阈值,则将残差分为4等分再编码,重复该过程直到绝对误差之和小于预设的阈值或达到最小图像块.实验结果表明,相对于全搜索的矢量量化方法,在相同码率下,算法编码时间较短且重建图像质量较好. 相似文献
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线谱对参数预测多级矢量量化联合优化算法 总被引:1,自引:0,他引:1
提出了一种线谱对参数预测多级矢量量化联合优化算法.该算法对预测系数和多级矢量量化采用渐进闭环设计,通过迭代实现预测系数和多级矢量量化设计的联合优化.在多级矢量量化设计过程中,采用迭代优化实现多级码本的联合优化.采用语音线谱对参数对量化算法进行测试.测试结果表明,与传统算法相比,该量化算法可以减小线谱对参数量化失真.提高编码语音质量. 相似文献
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提出基于小波变换 (WT)的矢量量化 (V Q)的遥感图象压缩编码方法。采用二维 WT消除象素间的空间相关性 ,然后对变换后的小波系数进行 VQ压缩编码。实验结果表明 :该方法可获得 10倍压缩比 ,峰值信噪比(PSNR)为 30 .5 2。本方法明显优于 JPEG方法 ,而且没有方块效应。该方法可用于各种遥感图象压缩 ,压缩比和PSNR这两项指标与 JPEG压缩方法相比 ,也有明显的提高。 相似文献
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在分析神经网络竞争学习算法和模糊C均值算法的基础上,提出了模糊竞争学习算法,并对模糊隶属度函数进行了探讨。理论分析和实验结果表明,模糊竞争学习算法用于图象矢量量化压缩编码是一种非常有效的方法。 相似文献
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矢量量化因其压缩比大,解码简单效率高成为实时绘制系统中大规模纹理压缩主要使用的方法。文献[1]介绍的基于矢量量化方法针对纹理金字塔压缩取得了很大的成功。在此基础上使用一个特征值数据本,一个残差矢量码本和索引表对金字塔纹理的各层进行压缩,在保持实时性的同时提高了压缩比。使用了改进的SOFM码本生成算法,实验表明其码本质量优于传统的码本生成算法。 相似文献
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Agustin Ramirez-Agundis Rafael Gadea-Girones Ricardo Colom-Palero Javier Diaz-Carmona 《Journal of Real-Time Image Processing》2007,2(4):271-280
This paper presents a scheme and its Field Programmable Gate Array (FPGA) implementation for a system based on combining the
bi-dimensional discrete wavelet transformation (2D-DWT) and vector quantization (VQ) for image compression. The 2D-DWT works
in a non-separable fashion using a parallel filter structure with distributed control to compute two resolution levels. The
wavelet coefficients of the higher frequency sub-bands are vector quantized using multi-resolution codebook and those of the
lower frequency sub-band at level two are scalar quantized and entropy encoded. VQ is carried out by self organizing feature
map (SOFM) neural nets working at the recall phase. Codebooks are quickly generated off-line using the same nets functioning
at the training phase. The complete system, including the 2D-DWT, the multi-resolution codebook VQ, and the statistical encoder,
was implemented on a Xilinx Virtex 4 FPGA and is capable of performing real-time compression for digital video when dealing
with grayscale 512 × 512 pixels images. It offers high compression quality (PSNR values around 35 dB) and acceptable compression
rate values (0.62 bpp).
相似文献
Javier Diaz-CarmonaEmail: |
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The VQ-based data hiding technique has not received much attention compared to various spatial domain-based data hiding techniques in digital images. Consequently, a new data hiding scheme, applied in the VQ-compressed domain of cover images, is introduced in this article. To provide more hiding capacity for secret data and to keep an acceptable bit rate for the compressed cover images, the search-order-coding (SOC) algorithm was implemented to compress the VQ indices of the cover images in the process of data hiding. During the process of data hiding, the proposed scheme embeds secret data into the compressed VQ indices of the cover image adaptively, adjusting the bit rate according to the size of the secret data and the compressed cover image. In addition, the hiding process induces no extra coding distortion. Experiments show that the receiver can efficiently receive both the secret data and the compressed cover image simultaneously with an acceptable bit rate. Simulation results also demonstrate that our proposed scheme outperforms earlier proposed methods. 相似文献
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提出了基于人眼视觉属性和应用小波树结构2快速图象编码的矢量量化图象编码方法,简称为树结构快速矢量量化编码。在分析此方法矢量量化特点之后,设计产生码本的统计方法,并提出了矢量量化编码的快速算法。 相似文献
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An image representation method using vector quantization (VQ) on color and texture is proposed in this paper. The proposed method is also used to retrieve similar images from database systems. The basic idea is a transformation from the raw pixel data to a small set of image regions, which are coherent in color and texture space. A scheme is provided for object-based image retrieval. Features for image retrieval are the three color features (hue, saturation, and value) from the HSV color model and five textural features (ASM, contrast, correlation, variance, and entropy) from the gray-level co-occurrence matrices. Once the features are extracted from an image, eight-dimensional feature vectors represent each pixel in the image. The VQ algorithm is used to rapidly cluster those feature vectors into groups. A representative feature table based on the dominant groups is obtained and used to retrieve similar images according to the object within the image. This method can retrieve similar images even in cases where objects are translated, scaled, and rotated. 相似文献
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林其伟 《计算机工程与应用》2007,43(35):68-70
提出一种基于矢量量化和DCT的多重鲁棒性水印算法,所提算法利用人类HVS及图像特征将不同的水印信号分别嵌入到载体图像的码书和DCT域中,通过自适应选择嵌入参数,保证水印算法的不可见性及抗攻击性能。实验结果表明所提水印算法比基于扩频调制的水印算法在抵抗各种信号处理所带来的攻击的鲁棒性方面有较大的改进,特别在抵抗同谋攻击方面具有较好的鲁棒性。 相似文献
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使用独立分量分析(ICA)来提取说话人特征并与矢量量化(VQ)判决方法相结合,实现了一个高性能的基于ICA特征的VQ (ICA VQ)说话人识别系统。通过ICA变换得到说话人语音特征基函数系数用于生成VQ码书,并导出包含能量失真的ICA VQ码书失真测度和质心确定条件,生成最终的判决。仿真实验中ICA提取的特征分别用于不同系统实现说话人确认任务,各系统的DET曲线对比验证了VQ方法用于ICA特征分类判决的优势,同时不同码书尺寸下的等差率(EER)对比证明了VQ码书设计的有效性。 相似文献
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A visual attention-based bit allocation strategy for video compression is proposed. Saliency-based attention prediction is used to detect interesting regions in video. From the top salient locations from the computed saliency map, a guidance map is generated to guide the bit allocation strategy through a new constrained global optimization approach, which can be solved in a closed form and independently of video frame content. Fifty video sequences (300 frames each) and eye-tracking data from 14 subjects were collected to evaluate both the accuracy of the attention prediction model and the subjective quality of the encoded video. Results show that the area under the curve of the guidance map is 0.773 ± 0.002, significantly above chance (0.500). Using a new eye-tracking-weighted PSNR (EWPSNR) measure of subjective quality, more than 90% of the encoded video clips with the proposed method achieve better subjective quality compared to standard encoding with matched bit rate. The improvement in EWPSNR is up to over 2 dB and on average 0.79 dB. 相似文献
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Production model based digital video segmentation 总被引:20,自引:1,他引:19
Effective and efficient tools for segmenting and content-based indexing of digital video are essential to allow easy access to video-based information. Most existing segmentation techniques do not use explicit models of video. The approach proposed here is inspired and influenced by well established video production processes. Computational models of these processes are developed. The video models are used to classify the transition effects used in video and to design automatic edit effect detection algorithms. Video segmentation has been formulated as a production model based classification problem. The video models are also used to define segmentation error measures. Experimental results from applying the proposed technique to commercial cable television programming are presented. 相似文献
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As the network bandwidth has grown rapidly, it has become common to share a large number of still images via the Internet by means of batch transmission. Unfortunately, most existing methods encrypt only a single image, so there is room for improvement in our ability to send batches of images at one time. A complete reconstruction of the methods is sometimes necessary, especially when considering performance criteria. This paper presents a novel batch-image encryption algorithm that combines Vector Quantization (VQ) and additional index-compression process to benefit from their computational efficiency and low transmission bandwidth without affecting the original compression rate. The experimental results show the performance of this new scheme in terms of compression rate and computational cost. 相似文献