9/6/2023 0 Comments Metaimage volumeSometimes it is impossible to scan long object in a CT-scanner with high resolution at once. The approach involves minimizing the following expression:į=\int_ In order to produce smooth, continuous (H1 space) density field least squares approximation is proposed. Distance of the integration points is calculated in BoneRemodeling::SurfaceKDTree class, subsequently it is used for density calculation at Gauss points in BoneRemodeling::OpCalulatefRhoAtGaussPts. Thanks to this, voxels involved into Partial Volume Effects will not be taken into consideration during collection data for integration points. When -dist_tol parameter is used, sampling cube at every integration close to the mesh surface will be shifted by value equal to -cube_size defined. Sampling cubes on the surface of mesh are shifted towards inside of the object. For example:Įffect of the dist_tol parameter. For density mapping simple MetaImage is used, its consists raw file that stores value of each voxel and MetaHeader file (. MetaImage is the text-based tagged file format for medical images included in MoFEM library. All input files used in this example can be found in the example directory. Subsequently two parameters (a,b) for linear image data - density field relation has to by defined, otherwise direct CT values from the image will be mapped.įollowing description and line commands are in presumption that users parent working directory is users_modules/bone_remodelling/ in build directory. 3D Slicer or by the conversion of standard DICOM format to Metafile by means of many available converters, like MRIConvert. It can be usually exported from the program that was used for segmentation e.g. In order to conduct mapping the user has to provide CT scan data in. raw (3D image) and corresponding finite elements mesh (. The proposed metaimage display with the encryption functionality has advantages such as continuous grayscale modulation, ultrathinness, and high density, which can be applied in ultracompact image displays, high-end anti-counterfeiting, high-density optical information storage, information encryption, etc.Workflow diagram. We experimentally demonstrate this concept by encoding a Lena image with pixels of 1000 × 1000 into a silver nanopolarizer-based metasurface and decoding/encrypting it in a polarization-controlled optical setup. By randomly selecting the orientation angle among two choices, the metaimage will be blurred or even hidden, except for the polarization direction of 0° for the original image and 90° for its contrast reversed partners. Specifically, for each metaimage pixel, there are two options for the orientation angle of the nanopolarizer corresponding to an equal grayscale value. Here, inspired by the orientation degeneracy of the Malus law, we show that metaimage displays can be controlled in two fixed polarization directions, merely by reconfiguring the orientations of nanopolarizers. One unique characteristic of the Malus-assisted image display technique is that no matter the polarization direction of incident LP light, the image with different contrast always appears, which would affect the security of a metaimage. Governed by the Malus law, nanopolarizer-based metasurfaces can continuously modulate the intensity of incident linearly polarized (LP) light pixel-by-pixel, which has been applied to display metaimages with ultracompactness and high resolution.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |