2005 Vol. 30, No. 2
According to the history of lunar detection, the relationship between selenodesy and lunar detection is reviewed , and the focus of the lunar detection and the lunar detection plan of China are summarized. The key technologies of selenodesy are presented, and the applications of selenodesy to the lunar detection are discussed.
On the basis of remote sensing image classification, this paper introduces a method for updating urban maps through high resolution remote sensing image. The RGB-HIS transformation technique is considered to merge spectral and spatial information, an appropriate filter for the edge extraction has been used. An MLP classifier is trained to produce a labeled image, focusing on urban buildings and roads, with great accuracy in test even if a limited training set is used. The result reveals a good feasibility of the classified image for monitoring the presence of changes in urban areas.
This paper introduces briefly the principle of coordinate transformation between the spatial information multi-grids. By comparing the coordinate accuracy of the affine transformation and rigorous coordinate transformation, it is found that the coordinate accuracy of affine transformation instead of rigorous coordinate transformation is higher than map presentation accuracy in the grid of proper scale. The experimental results provide the scale criterion for both the division of spatial information multi-grid and the manner of spatial data organization which is adapt to spatial coordinate transformation.
This paper introduces a mathematic model of image texture reorganization aiming at reducing image files and textures involved in 3D model reconstruction. A practical problem-solving method is also introduced in reducing texture data volume. Supposed results are acquired in an experiment on the visualization about two plane models
This paper compares SVD (singular value decomposition) with DCT (discrete cosine transform) in the face recognition, and concludes that SVD is less effective than DCT in recognition ratio and time cost. Experimental results show that SVD is an available feature extraction method, but is not a best one for pattern recognition
In this paper, an approach is presented to calibrate the distortion of CCD array digital cameras. Firstly, we use standard 3D calibration objects to determine the internal geometric and optical camera’s characteristics. Secondly, according to the principle that the projection of every line in space onto the camera is still a line if a camera follows the pinhole model, we propose a new method for calibrating the random distortion with good precision. Finally,we apply the approach to the calibrating process of the digital camera of UAVRS-Ⅱ system. Experiment results indicate that this kind of calibration method have reached successful test effect.
Image sequence acquired by digital cameras has the advantages of high-overlap and redundancy of observations, which makes it more and more popular in 3D reconstruction. Precision of relative orientation and forward intersection with high overlapping image sequence is analyzed. The higher the overlap is, the better the result of relative orientation is. The more images are used, and the bigger the intersection angle is, the higher the precision of forward intersection is. In practice, images with 80 % overlap are optimal for 3D reconstruction and other applications.
This paper discusses the situation of digital remote sensing techniques which has been applied to monitor the land use dynamic change, and introduces the notion of land use dynamic monitoring by remote sensing. The land use change in Guangxi province in 2002 and 2003 is detected by using direct classification of composed multi-temporal MODIS images. The results show PCA bands can well inherit the original images to achieve better accuracy.
This paper presents a new method based on both linear features and gray information of image. Use the Canny algorithm to extract the edge of two different images, then, according to the edge and gray information, find the discriminate of the images. This method is suitable for urban change-detection using high-resolution satellite image. The result of the experiment shows that the method is feasible.
With the in-situ soil moisture data of Hubei province in June and July 2003, this papar brings out CCFD, CCD,CFDR and temperature difference (TD) into the drought monitoring model,analyzes their relationships and to what extent they influenced the integrated drought index,so as to make certain their powers in this model. The results show that these parameters have their independence and importance,and using the correlation coefficients as powers is better than that of equal powers.
Based on spectral profiles sampling from EOS MODIS data, the spectral characteristics of water, cloud, snow, surface features and fog are analyzed; Channels suitable for fog detection are discovered. On the basis of this, the advection fog, which occurred at 13:21 on Jan.5, 2004 and at 01:27 on Jan.6, 2004, in Liaoning Province and Liaodong Gulf, is detected. Validated from ground truth data, the result shows that MODIS data has great potential in fog detection.
This paper presents an algorithm to compute initial values of camera’s orientation elements and height of building with the technique of CSG, DLT and space resection of a single image. With all lines of buildings on image (especially plumb lines of buildings), camera’s orientation elements can be more precise and complete building reconstruction.
As the Hu’s invariant moments cannot deal with the changed gray during detecting changed image, a revised histogram invariant moment’s algorithm is put forward based on the histogram invariant moments. The invariant moments of image histogram filtered is calculated and revised with the related coefficient of the two images. Two symbol images, a reference image and an aim image, are tested to detect the change. The experiment shows that the method can resist the effect of the brightness and the contrast change of images.
Surface model reconstruction from 3D irregular points is of great importance in variable fields such as photogrammetry, 3D reconstruction based on images, scientific computing visualization, etc. 3D points can be obtained with many mature methods such as photogrammetry, laser scanning, etc. While the surface model reconstruction from 3D irregular points is still a difficult problem. In this paper, a novel algorithm based on projective constrain for automatic generation of 3D surface model is proposed. It can make full use of projective constrain of points and make surface reconstruction easy. Experiment results show its reliability.
Based on the character of LIDAR data, a new fusion median filtering algorithm is proposed. The algorithm, median filtering algorithm and mean filtering algorithm are applied, and their results are compared to different evaluation parameters. The conclusion proves the improvement of the proposed algorithm in keeping the advantage of median filtering algorithm under the condition of preserving unclear edge of the image.
If every pixel in an image is regarded as column and the image can be a columniation, then the image face can be calculated by a simple, accurate method. On the basis of this method, a new arithmetic for calculating fractal dimension is proposed with the theory of FBM. Experiment results show that the arithmetic is better than several current arithmetics of fractal dimension.
This paper discusses the data models, data storage, spatial index, data manipulation of remote sensing data management based on object oriented RDBMS and RDBMS middleware by taking Oracle Georasrer and ArcSDE as examples, and analyzes the relationship between image block size and RDBMS data block size, pyramid level, image compression ratio by taking the performance into consideration.
】This paper introduces a method for propositional logic calculation. Based on the Landsat TM data in 1993 and 2002 in Wuhan area, this paper discusses the urban built-up cover change. Last, this paper comes to a conclusion that it is of theoretical and practical significance that this method is used to study dynamic land use change.
This paper discusses the importance of synthetic evaluation in the course of executing geographic information engineering, and introduces the basic concept, characters, classes of multi-index synthetic evaluation method, evaluates factors and evaluating procedure, and analyzes the key points in the procedure.
This paper puts forward a method of interoperability between heterogeneous geographic information systems based on the cooperation of the standard spatial ontology and the hybrid semantic ontology. By the cooperation on the two ontologies, the interoperability of heterogeneous spatial data and semantics can be obtained.
A new concept of geospatial information atomic service is proposed for distributed geospatial information service (GIService). The interoperability model and interoperability layered structure of the atomic services are presented. Subsequently the integration framework of atomic services is put forward, which includes service classification framework, service chaining patterns and service integrating model composed of atomic services, molecule services, process services and solution services.