Changqing Zhu

Learn More
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)
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 Land-sat 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)
511 Fig. 2. Error in path delay (PD) retrieval if a simplified 1.2 mm/y correction is applied for all values of PD rather than correcting the TB at 18 GHz directly and then reprocessing the TBs through the PD retrieval algorithm. Data is to the PD retrieval algorithm. The difference between these two PD estimates is shown in Fig. 2 as a function of the(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)
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)
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)
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)
  • 1