Changqing Zhu

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Recent developments in satellite and sensor technologies have provided high-resolution satellite images. Image fusion techniques can improve the quality, and increase the application of these data. This paper addresses two issues in image fusion (a) the image fusion method and (b) corresponding quality assessment. Firstly, a multi-band wavelet-based image(More)
This paper presents an approach, with emphasis on the newly proposed line segment matching method, for extracting urban road networks from high-resolution satellite images. The approach is based on the characteristics of the images, knowledge about road networks, and the related mathematical models. The approach is applied to several images of urban areas(More)
A new image encryption algorithm of double scrambling based on ASCII code of image matrix element is proposed in this paper. The new algorithm implements position scrambling and gray scrambling at the same time, and overcomes the shortcoming of traditional algorithm that single algorithm can only deal with position scrambling but not gray scrambling(More)
With the development of remote sensing technology, fusion of remotely sensed images, such as SPOT panchromatic (SPOT P) with SPOT multispectral images (SPOT XS) or Landsat Thematic Mapper (TM), has become more important in order to obtain richer information in the spatial and spectral domains simultaneously. Many fusion methods have been developed based on(More)
For the decision matrix given in the form of interval, the result can not reflect how many the affirmative component and denial component because the evaluation result of alternative attribute is only presented by interval. This paper presents the concept of supporting set, opposing set, and supporting interval, opposing interval with the help of golden(More)
For the characteristics of digital watermarking of the vector geospatial data, the DFT (discrete Fourier transform) blind watermarking model is put forward based on QIM(quantized index modulation) idea. First vector geospatial data carries on DFT. The watermark data are embedded in the magnitude of DFT through quantification, then inverse DFT transform, the(More)
To fill an elongated polygon, traditional Edge Marking Fill Algorithm can not deal properly. Basing on it, this paper especially presents a designed Edge Marking Fill algorithm aiming at elongated polygon. The idea is to design an algorithm, which signs out the pixel activated double times, then bounce out the function of edge marking fill algorithm and(More)
In this paper, a three-dimensional error model of grid digital elevation model (DEM) is proposed based on the reconstructed contours. Though analyzing the construction of three-dimensional error model, the paper disassembles the three-dimensional error to a series of triangular pyramids and quadrangular pyramids, and it can make the calculation simpler. The(More)
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