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43 results about "Quadtree segmentation" patented technology

Remote-sensing image compression method for discrete wavelet transform based on self-adaptation direction prediction

The invention discloses a remote-sensing image compression method for discrete wavelet transform based on self-adaptation direction prediction and belongs to the technical field of remote-sensing image processing. The method comprises the steps that 1) 15 directions which are formed by close-end integer and fraction pixels and far-end integer pixels are considered in a combined mode, a direction graph is established; 2) remote-sensing images are subjected to two-dimensional discrete wavelet transform based on self-adaptation direction prediction, namely quadtree division based on direction consistency is used for dividing the remote-sensing images to a plurality of image blocks which are not overlapped, a new direction prediction model is used for obtaining the best transformation direction of each image block, lifting wavelet transform is completed in the direction; 3) a transformed image coefficient is subjected to SPIHT coding, direction information is subjected to self-adaptation arithmetic coding, and a final code stream is obtained. According to the method, visual quality and peak signal-to-noise ratio of the remote-sensing images are effectively improved, computing complexity of direction wavelet transform is lowered, and the method can be widely used for efficient coding compression of the aviation and satellite remote-sensing images.
Owner:BEIJING NORMAL UNIVERSITY

Fractal image compression method based on combination of quad tree and neighborhood searching

The invention provides a fractal image compression method based on the combination of a quad tree and neighborhood searching. The method comprises the following steps of: setting the maximum and minimum depths of the quad tree and an error threshold value; dividing an image into value region blocks according to the minimum depth; extracting a value region block to be matched; searching for a neighborhood definitional domain block corresponding to the value region block to be matched; calculating affinity, matching the affinity and the value region block, and calculating a mean square error of the affinity and the value region block; comparing the mean square error with the threshold value; if the mean square error is small, recording a current value region block, a current definitional domain block and the affinity; if the mean square error is greater, judging whether the current value region block is the maximum depth or not, recording the current value region block, a definitional domain block with the lowest error, and the affinity if the current value region block is the maximum depth, and if the current value region block is not the maximum depth, dividing the value region block into sub-blocks according to the quad tree as value region blocks to be matched, correspondingly reducing the corresponding definitional domain block, and repeating the matching process; and judging whether all the value region blocks to be matched are matched or not, and if not all the value region blocks to be matched are matched, repeating the matching process. Searching time is shortened, and high image recovery quality is ensured.
Owner:SHANGHAI INST OF APPLIED PHYSICS - CHINESE ACAD OF SCI

Terrain multi-scale TIN (Triangulated Irregular Network) online visualization method oriented to virtual earth

The invention provides a terrain multi-scale TIN (Triangulated Irregular Network) online visualization method oriented to the virtual earth. The method comprises the following steps of global multi-scale TIN scale parameter mathematical model construction, terrain multi-scale TIN automatic construction and virtual segmentation under characteristic constraints, the online visualization of a multi-scale TIN topography spherical surface and real-time crack elimination, wherein the step of the terrain multi-scale TIN automatic construction and virtual segmentation under characteristic constraintsis realized as follows; the step of the online visualization of the multi-scale TIN topography spherical surface comprises the step of carrying out calculation to obtain visual terrain blocks of different levels according to point-of-sight information; and the step of the real-time crack elimination comprises the following step of carrying out quick decoding during real-time visualization to finish the edge connection of the adjacent boundary of terrain blocks of different levels. By use of the method, while the structural flexibility of the TIN is kept, the multi-scale irregular modeling andthe quadtree segmentation of a large-scale terrain are realized, meanwhile, the seamless real-time rendering of a mixed scale TIN terrain is supported, the terrain data processing and expression accuracy of the virtual earth can be greatly improved, a seamless fusion ability for irregular GF spatial data is also greatly improved, so that the high-fidelity expression requirement of a geographical environment can be met, and each category of reliable geographical analysis application can be supported.
Owner:WUHAN UNIV

Thermodynamic diagram generation method and system considering space density difference

The invention discloses a thermodynamic diagram generation method and system considering space density difference, and the method comprises the steps: collecting experiment data, and storing the experiment data in a form of a space point group; in combination with a thermodynamic diagram scale, calculating a real distance corresponding to the screen resolution, and taking the real distance as a side length threshold value of quadtree segmentation; counting the number of the spatial point groups, and calculating a point number threshold value; carrying out quadtree segmentation based on point number threshold and side length threshold constraints on the spatial point group, and extracting block side length information reflecting a point group distribution aggregation degree; calculating adaptive bandwidth values point by point according to the corresponding relation between the side length of the quadtree block and the bandwidth parameter of the nearest neighbor kernel density function;and substituting the adaptive bandwidth value into a nearest neighbor kernel density function, calculating a nearest neighbor kernel density function value, and presenting a result in a Heat-map form. According to the method, quadtree segmentation and the nearest neighbor method are combined, the bandwidth values are calculated point by point, and the real distribution characteristics of the spatial point group are expressed more objectively.
Owner:HUBEI UNIV

A Remote Sensing Image Compression Method Based on Adaptive Direction Prediction Discrete Wavelet Transform

The invention discloses a remote-sensing image compression method for discrete wavelet transform based on self-adaptation direction prediction and belongs to the technical field of remote-sensing image processing. The method comprises the steps that 1) 15 directions which are formed by close-end integer and fraction pixels and far-end integer pixels are considered in a combined mode, a direction graph is established; 2) remote-sensing images are subjected to two-dimensional discrete wavelet transform based on self-adaptation direction prediction, namely quadtree division based on direction consistency is used for dividing the remote-sensing images to a plurality of image blocks which are not overlapped, a new direction prediction model is used for obtaining the best transformation direction of each image block, lifting wavelet transform is completed in the direction; 3) a transformed image coefficient is subjected to SPIHT coding, direction information is subjected to self-adaptation arithmetic coding, and a final code stream is obtained. According to the method, visual quality and peak signal-to-noise ratio of the remote-sensing images are effectively improved, computing complexity of direction wavelet transform is lowered, and the method can be widely used for efficient coding compression of the aviation and satellite remote-sensing images.
Owner:BEIJING NORMAL UNIVERSITY

Image rendering processing method and device, storage medium and electronic equipment

The embodiment of the invention provides an image rendering processing method and device, a storage medium and electronic equipment, and the method comprises the steps: receiving a three-dimensional graphic object, and carrying out the cutting of a view cone of the three-dimensional graphic object, thereby obtaining a three-dimensional graphic cone; the method comprises the following steps: performing quadtree segmentation on a three-dimensional graphic cone to generate three-dimensional graphic sub-objects; the rendering complexity of the three-dimensional graph sub-object is calculated; under the condition that the rendering complexity of the three-dimensional graph sub-object does not meet the rendering condition, performing quadtree segmentation on the three-dimensional graph sub-object for several times to obtain a plurality of target three-dimensional graph sub-objects meeting the rendering condition; respectively rendering the plurality of target three-dimensional graph sub-objects on the to-be-rendered plane to obtain rendered target three-dimensional graph sub-objects; and splicing the rendered target three-dimensional graph sub-objects to obtain a two-dimensional rendering graph corresponding to the three-dimensional graph object. According to the method and the device, the problem of low graphic rendering efficiency is solved, and the effect of improving the graphic rendering efficiency is further achieved.
Owner:ZTE CORP +1
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