190 results about "Level set method" patented technology

The invention discloses an image partition method of synthetic aperture radars (SAR) which is based on a level set and relates to the application technology of radar remote sensing. The method comprises the following procedures: an SAR echoed signal is acquired by a receiver and a hybrid probability model of an SAR image is computed; a boundary detection operator is computed according to the hybrid probability model; an energy functional based on a boundary information is acquired by combining a geodesic active contour model with the boundary detection operator; the energy functional based on a region information is computed and a partition model is defined as the weighted sum of the energy functional which are based on the region information and the boundary information; the partition model is minimized by a variation method, so as to acquire the partition result of the SAR image. As the invention uses the level set method for transforming curve movement into curved surface movement, even if the target boundary is disunited or merged in the image partition, the topology structure of the curved surfaces does not change, and simultaneously the invention does not need a noise preprocessing procedure, thus improving the precision and the applicability of the SAR image partition.

The invention discloses a method for detecting a picture contour based on the combination of a level set and a watershed, which mainly solves the problem that the prior method generates picture over-segmentation results and cannot obtain an accurate target contour. The method is achieved according to the following steps: (1) detecting the target contour of an input picture by using a level set method to obtain an initial target and a background binary segmentation result; (2) using the detected target contour as an internal control mark of the watershed; (3) performing range conversion and watershed conversion on the internal control mark in turn, and using an obtained watershed line result as an external control mark of the watershed; (4) using the internal control mark and the external control mark to correct a gradient picture of the input picture; and (5) performing the watershed conversion on the corrected gradient picture so as to detect the target contour in the picture. The method avoids the picture over-segmentation, has the advantage of positioning the boundary accurately, and can be applied to segmenting foregrounds and backgrounds and detecting target external contours.

The present invention is level set system for implementing interactive editing operators for surfaces. Level set models are deformable implicit surfaces where the deformation of the surface (editing operation) is controlled by a speed function in the level set partial differential equation. The level set system overcomes the self-interaction problems associated with mesh models. One embodiment takes scan converts input models such as polygon mesh, NURBS, CSGS models into level set models. An interface is provided by which models can be edited with editing operators such as blending, smoothing, embossing, etc. One embodiment utilizes several methods to optimize computations related to the editing operators. For example, shortest distance calculations, bounding boxes, numerical integration, and the sparse-field methods are disclosed for the implementation of the level set deformation operator embodiments including blending, smoothing sharpening, and embossing. The resulting level sets model can be volume rendered or extracted to a polygon mesh.