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图象放缩技术与实现
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作者 陈桂林 孟正大 《计算机工程与应用》 CSCD 北大核心 1997年第3期43-45,共3页
本文介绍了一种全新的基于图块的图象放缩方法,并通过与传统放缩方法的比较,阐明了其优越性,作者认为,这是一条行之有效的新途径。
关键词 放大 图象缩小 处理
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地理课本中地图的作用和绘制
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作者 马宗尧 《课程.教材.教法》 1987年第6期48-50,共3页
地图是把地球表面按比例缩小的图象。在地图上叶以表示一个地区以至整个地球上的地理事物的分布概况,便于人们去了解、研究、探讨地理事物的分布,及其相互关系和发展变化的规律。地图的用途非常广泛,国家建设需要地图,人们日常生活和外... 地图是把地球表面按比例缩小的图象。在地图上叶以表示一个地区以至整个地球上的地理事物的分布概况,便于人们去了解、研究、探讨地理事物的分布,及其相互关系和发展变化的规律。地图的用途非常广泛,国家建设需要地图,人们日常生活和外出旅游等需要地图,地理科学研究需要地图,在地理教学中地图更是不可少的工具。 展开更多
关键词 地理课本 地理教学 地理事物 缩小 示意 三个经济地带 分布 地理科学 景观
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OPTIMAL WAVELET FILTER DESIGN FOR REMOTE SENSING IMAGE COMPRESSION
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作者 Yang Guoan Zheng Nanning Guo Shugang 《Journal of Electronics(China)》 2007年第2期276-284,共9页
A new approach for designing the Biorthogonal Wavelet Filter Bank (BWFB) for the purpose of image compression is presented in this letter. The approach is decomposed into two steps. First, an optimal filter bank is de... A new approach for designing the Biorthogonal Wavelet Filter Bank (BWFB) for the purpose of image compression is presented in this letter. The approach is decomposed into two steps. First, an optimal filter bank is designed in theoretical sense based on Vaidyanathan’s coding gain criterion in SubBand Coding (SBC) system. Then the above filter bank is optimized based on the criterion of Peak Signal-to-Noise Ratio (PSNR) in JPEG2000 image compression system, resulting in a BWFB in practical application sense. With the approach, a series of BWFB for a specific class of applications related to image compression, such as remote sensing images, can be fast designed. Here, new 5/3 BWFB and 9/7 BWFB are presented based on the above approach for the remote sensing image compression applications. Experiments show that the two filter banks are equally performed with respect to CDF 9/7 and LT 5/3 filter in JPEG2000 standard; at the same time, the coefficients and the lifting parameters of the lifting scheme are all rational, which bring the computational advantage, and the ease for VLSI implementation. 展开更多
关键词 Wavelet filter OPTIMIZATION Coding gain Remote sensing image JPEG2000
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Listless zerotree image compression algorithm 被引量:2
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作者 LIAN Jing WANG Ke 《Optoelectronics Letters》 EI 2006年第5期376-378,395,共4页
In this paper,an improved zerotree structure and a new coding procedure are adopted,which improve the reconstructed image qualities. Moreover, the lists in SPIHT are replaced by flag maps, and lifting scheme is adopte... In this paper,an improved zerotree structure and a new coding procedure are adopted,which improve the reconstructed image qualities. Moreover, the lists in SPIHT are replaced by flag maps, and lifting scheme is adopted to realize wavelet transform, which lowers the memory requirements and speeds up the ceding process. Experimental results show that the algorithm is more effective and efficient compared with SPIHT. 展开更多
关键词 压缩算法 零树结构 重建 小波传输
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Entropy of images after wavelet transform
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作者 田逢春 《Journal of Chongqing University》 CAS 2008年第1期73-78,共6页
We studied the variation of image entropy before and after wavelet decomposition, the optimal number of wavelet decomposition layers, and the effect of wavelet bases and image frequency components on entropy. Numerous... We studied the variation of image entropy before and after wavelet decomposition, the optimal number of wavelet decomposition layers, and the effect of wavelet bases and image frequency components on entropy. Numerous experiments were done on typical images to calculate (using Matlab) the entropy before and after wavelet transform. It was verified that, to obtain minimal entropy, a three-layer decomposition should be adopted rather than higher orders. The result achieved by using biorthogonal wavelet decomposition is better than that of the orthogonal wavelet decomposition. The results are not directly proportional to the vanishing moment, however. 展开更多
关键词 image processing ENTROPY wavelet transform data compression wavelet bases
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