scholarly journals Three-Dimensional Cloud Volume Reconstruction from the Multi-angle Imaging SpectroRadiometer

2018 ◽  
Vol 10 (11) ◽  
pp. 1858 ◽  
Author(s):  
Byungsuk Lee ◽  
Larry Di Girolamo ◽  
Guangyu Zhao ◽  
Yizhe Zhan
Keyword(s):  
Three Dimensional ◽  
Correction Method ◽  
Heat Fluxes ◽  
Reconstruction Method ◽  
Ray Casting ◽  
Pixel Resolution ◽  
Reconstructed Volume ◽  
Ellipsoidal Surface ◽  
Cloud Mask ◽  
Ray Casting Algorithm

Characterizing 3-D structure of clouds is needed for a more complete understanding of the Earth’s radiative and latent heat fluxes. Here we develop and explore a ray casting algorithm applied to data from the Multi-angle Imaging SpectroRadiometer (MISR) onboard the Terra satellite, in order to reconstruct 3-D cloud volumes of observed clouds. The ray casting algorithm is first applied to geometrically simple synthetic clouds to show that, under the assumption of perfect, clear-conservative cloud masks, the reconstruction method yields overestimation in the volume whose magnitude depends on the cloud geometry and the resolution of the reconstruction grid relative to the image pixel resolution. The method is then applied to two hand-picked MISR scenes, fully accounting for MISR’s viewing geometry for reconstructions over the Earth’s ellipsoidal surface. The MISR Radiometric Camera-by-camera Cloud Mask (RCCM) at 1.1-km resolution and the custom cloud mask at 275-m resolution independently derived from MISR’s red, green, and blue channels are used as input cloud masks. A wind correction method, termed cloud spreading, is applied to the cloud masks to offset potential cloud movements over short time intervals between the camera views of a scene. The MISR cloud-top height product is used as a constraint to reduce the overestimation at the cloud top. The results for the two selected scenes show that the wind correction using the cloud spreading method increases the reconstructed volume up to 4.7 times greater than without the wind correction, and that the reconstructed volume generated from the RCCM is up to 3.5 times greater than that from the higher-resolution custom cloud mask. Recommendations for improving the presented cloud volume reconstructions, as well as possible future passive remote sensing satellite missions, are discussed.

scholarly journals Three-Dimensional Cloud Volume Reconstruction from the Multi-Angle Imaging SpectroRadiometer

2018 ◽  
Author(s):  
Byungsuk Lee ◽  
Larry Di Girolamo ◽  
Guangyu Zhao ◽  
Yizhe Zhan
Keyword(s):  
Three Dimensional ◽  
Correction Method ◽  
Heat Fluxes ◽  
Reconstruction Method ◽  
Ray Casting ◽  
Pixel Resolution ◽  
Ellipsoidal Surface ◽  
Short Time ◽  
Terra Satellite ◽  
Cloud Mask

Abstract: Characterization the 3-D structure of clouds is needed for a more complete understanding of the Earth's radiative and latent heat fluxes. Here we develop and explore a “ray casting” algorithm applied to the Multi-angle Imaging SpectroRadiometer (MISR) on board the Terra satellite, to reconstruct 3-D cloud volumes for observed clouds. The ray casting algorithm is first applied to geometrically simple synthetic clouds to show that, under the assumption of perfect, clear-conservative cloud masks, the reconstruction method yields overestimation whose magnitude depends on the cloud geometry and the resolution of the reconstruction grid relative to the image pixel resolution. The method is then applied to two select MISR scenes, fully accounting for MISR’s viewing geometry for reconstructions over the Earth’s ellipsoidal surface. The MISR Radiometric Camera-by-camera Cloud Masks at 1.1 km resolution and custom cloud masks at 275 m resolution independently derived from MISR RGB channels are used as input cloud masks. A wind correction method, termed “cloud spreading”, is devised and applied to the cloud masks to offset potential cloud movements over short time intervals (around 7 minutes at maximum) between the cameras. The MISR cloud top height product is used as a constraint to reduce the overestimation at the cloud top. The reconstruction results show that their uncertainty is significant when the wind correction is applied, and that they have more refined structures when the input cloud mask has a higher resolution. Recommendations for improving the presented cloud volume reconstructions as well as for future passive remote sensing satellite missions are discussed.

scholarly journals Plane-Based Sampling for Ray Casting Algorithm in Sequential Medical Images

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Lili Lin ◽  
Shengyong Chen ◽  
Yan Shao ◽  
Zichun Gu
Keyword(s):  
Sampling Method ◽  
Three Dimensional ◽  
Ray Casting ◽  
The Novel ◽  
Novel Method ◽  
Fast Reconstruction ◽  
Intersection Points ◽  
Sequential Images ◽  
Ray Casting Algorithm ◽  
Conventional Algorithm

This paper proposes a plane-based sampling method to improve the traditional Ray Casting Algorithm (RCA) for the fast reconstruction of a three-dimensional biomedical model from sequential images. In the novel method, the optical properties of all sampling points depend on the intersection points when a ray travels through an equidistant parallel plan cluster of the volume dataset. The results show that the method improves the rendering speed at over three times compared with the conventional algorithm and the image quality is well guaranteed.

scholarly journals Three-Dimensional Cloud Structure Reconstruction from the Directional Polarimetric Camera

2019 ◽  
Vol 11 (24) ◽  
pp. 2894 ◽  
Author(s):  
Haixiao Yu ◽  
Jinji Ma ◽  
Safura Ahmad ◽  
Erchang Sun ◽  
Chao Li ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Satellite Observation ◽  
Extensive Study ◽  
Orthogonal Polarization ◽  
Reconstruction Method ◽  
Observation Data ◽  
Ray Casting ◽  
Cloud Structure ◽  
Radiation Transmission ◽  
Structure Reconstruction

Clouds affect radiation transmission through the atmosphere, which impacts the Earth’ s energy balance and climate. Currently, the study of clouds is mostly based on a two-dimensional (2-D) plane rather than a three-dimensional (3-D) space. However, 3-D cloud reconstruction is playing an important role not only in a radiation transmission calculation but in forecasting climate change as well. Currently, the study of clouds is mostly based on 2-D single angle satellite observation data while the importance of a 3-D structure of clouds in atmospheric radiation transmission is ignored. 3-D structure reconstruction would improve the radiation transmission accuracy of the cloudy atmosphere based on multi-angle observations data. Characterizing the 3-D structure of clouds is crucial for an extensive study of this complex intermediate medium in the atmosphere. In addition, it is also a great carrier for visualization of its parameters. Special attributes and the shape of clouds can be clearly illustrated in a 3-D cloud while these are difficult to describe in a 2-D plane. It provides a more intuitive expression for the study of complex cloud systems. In order to reconstruct a 3-D cloud structure, we develop and explore a ray casting algorithm applied to data from the Directional Polarimetric Camera (DPC), which is onboard the GF-5 satellite. In this paper, we use DPC with characteristics of imaging multiple angles of the same target, and characterize observations of clouds from different angles in 3-D space. This feature allows us to reconstruct 3-D clouds from different angles of observations. In terms of verification, we use cloud profile data provided by the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) to compare with the results of reconstructed 3-D clouds based on DPC data. This shows that the reconstruction method has good accuracy and effectiveness. This 3-D cloud reconstruction method would lay a scientific reference for future analysis on the role of clouds in the atmosphere and for the construction of 3-D structures of aerosols.

Concrete CT Image Quick Three-Dimensional Reconstruction Research

2017 ◽  
Vol 31 (10) ◽  
pp. 1757005 ◽  
Author(s):  
Liang Zhao ◽  
Chang-Hua Li ◽  
Fa-Ning Dang ◽  
Chu-Jun Li ◽  
Zhong-Xing Duan
Keyword(s):  
Adaptive Sampling ◽  
Three Dimensional ◽  
Concrete Specimen ◽  
Damage Mechanism ◽  
The Body ◽  
Reconstruction Method ◽  
Ray Casting ◽  
Ct Reconstruction ◽  
The Real ◽  
Random Aggregate

The research of the mechanical properties of concrete, a kind of heterogeneous composite material, was previously established on basis of the mathematical model of random aggregate, which is used to study and analyze the mesoscopic damage mechanism of concrete. Although the shape and distribution of aggregate in the model built by this method are closer to the real structure of concrete, there is still a big difference between them and the real concrete specimen. In order to solve the problem of large amount of redundant computation in the CT reconstruction of full size cube space, a fast reconstruction method based on ray-casting algorithm is proposed. First, a method integrating the new bounding box technology with the plane intersection algorithm clusters were adopted to cut the body data and ray-casting effectively, and then, the polygon scanning and conversion was utilized to reduce the number of cast rays, finally, the adaptive sampling method was used to avoid repeatedly sampling same voxel so that the reconstruction efficiency of whole algorithm and the feasibility of numerical calculation can be enhanced. The experimental results demonstrate that the proposed algorithm can greatly improve the 3D rendering speed of concrete CT without affecting the image quality. It provides a more effective and reliable approach for correctly analyzing the mesoscopic damage mechanism and mechanical characteristics of concrete.

scholarly journals Three-Dimensional Reconstruction-Based Vibration Measurement of Bridge Model Using UAVs

2021 ◽  
Vol 11 (11) ◽  
pp. 5111
Author(s):  
Zhihua Wu ◽  
Gongfa Chen ◽  
Qiong Ding ◽  
Bing Yuan ◽  
Xiaomei Yang
Keyword(s):  
3D Reconstruction ◽  
Three Dimensional ◽  
Correction Method ◽  
Reference Points ◽  
Image Correlation ◽  
Vibration Measurement ◽  
Reconstruction Method ◽  
The Real ◽  
Bridge Model ◽  
Dimensional Reconstruction

This paper presents a measurement method of bridge vibration based on three-dimensional (3D) reconstruction. A video of bridge model vibration is recorded by an unmanned aerial vehicle (UAV), and the displacement of target points on the bridge model is tracked by the digital image correlation (DIC) method. Due to the UAV motion, the DIC-tracked displacement of the bridge model includes the absolute displacement caused by the excitation and the false displacement induced by the UAV motion. Therefore, the UAV motion must be corrected to measure the real displacement. Using four corner points on a fixed object plane as the reference points, the projection matrix for each frame of images can be estimated by the UAV camera calibration, and then the 3D world coordinates of the target points on the bridge model can be recovered. After that, the real displacement of the target points can be obtained. To verify the correctness of the results, the operational modal analysis (OMA) method is used to extract the natural frequencies of the bridge model. The results show that the first natural frequency obtained from the proposed method is consistent with the one obtained from the homography-based method. By further comparing with the homography-based correction method, it is found that the 3D reconstruction method can effectively overcome the limitation of the homography-based method that the fixed reference points and the target points must be coplanar.

scholarly journals Fuzzy Mutual Information-Based Intraslice Grouped Ray Casting

2019 ◽  
Vol 28 (1) ◽  
pp. 77-86 ◽  
Author(s):  
R. Mehaboobathunnisa ◽  
A.A. Haseena Thasneem ◽  
M. Mohamed Sathik
Keyword(s):  
Image Quality ◽  
Mutual Information ◽  
Three Dimensional ◽  
Ray Casting ◽  
Two Dimensional ◽  
Volume Data ◽  
Grouping Strategy ◽  
Color Data ◽  
Ray Casting Algorithm ◽  
Data Group

Abstract The traditional ray casting algorithm has the capability to render three-dimensional volume data in the viewable two-dimensional form by sampling the color data along the rays. The speed of the technique relies on the computation incurred by the huge volume of rays. The objective of the paper is to reduce the computations made over the rays by eventually reducing the number of samples being processed throughout the volume data. The proposed algorithm incorporates the grouping strategy based on fuzzy mutual information (FMI) over a group of voxels in the conventional ray casting to achieve the reduction. For the data group, with FMI in a desirable range, a single primary ray is cast into the group as a whole. As data are grouped before casting rays, the proposed algorithm reduces the interpolation calculation and thereby runs with lesser complexity, preserving the image quality.

Three-dimensional reconstruction of the 40S ribosomal subunit from rabbit reticulocytes

1987 ◽  
Vol 45 ◽  
pp. 936-937
Author(s):  
Neng-Yu Zhang ◽  
Terence Wagenknecht ◽  
Michael Radermacher ◽  
Tom Obrig ◽  
Joachim Frank
Keyword(s):  
Three Dimensional ◽  
Ribosomal Subunit ◽  
Uranyl Acetate ◽  
Reconstruction Method ◽  
Single Exposure ◽  
Electron Dose ◽  
Ribosomal Subunits ◽  
40S Ribosomal Subunit ◽  
Dimensional Reconstruction ◽  
Rabbit Reticulocytes

We have reconstructed the 40S ribosomal subunit at a resolution of 4 nm using the single-exposure pseudo-conical reconstruction method of Radermacher et al.Small (40S) ribosomal subunits were Isolated from rabbit reticulocytes, applied to grids and negatively stained (0.5% uranyl acetate) in a manner that “sandwiches” the specimen between two layers of carbon. Regions of the grid exhibiting uniform and thick staining were identified and photographed twice (magnification 49,000X). The first micrograph was always taken with the specimen tilted by 50° and the second was of the Identical area untilted (Fig. 1). For each of the micrographs the specimen was subjected to an electron dose of 2000-3000 el/nm2.Three hundred thirty particles appearing in the L view (defined in [4]) were selected from both tilted- and untilted-specimen micrographs. The untilted particles were aligned and their rotational alignment produced the azimuthal angles of the tilted particles in the conical tilt series.

scholarly journals Automatic Reconstruction of Multi-Level Indoor Spaces from Point Cloud and Trajectory

Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3493
Author(s):  
Gahyeon Lim ◽  
Nakju Doh
Keyword(s):  
Point Cloud ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Reconstruction Method ◽  
Complex Environments ◽  
Indoor Space ◽  
Multi Level ◽  
Level Building ◽  
Indoor Spaces ◽  
Data Term

Remarkable progress in the development of modeling methods for indoor spaces has been made in recent years with a focus on the reconstruction of complex environments, such as multi-room and multi-level buildings. Existing methods represent indoor structure models as a combination of several sub-spaces, which are constructed by room segmentation or horizontal slicing approach that divide the multi-room or multi-level building environments into several segments. In this study, we propose an automatic reconstruction method of multi-level indoor spaces with unique models, including inter-room and inter-floor connections from point cloud and trajectory. We construct structural points from registered point cloud and extract piece-wise planar segments from the structural points. Then, a three-dimensional space decomposition is conducted and water-tight meshes are generated with energy minimization using graph cut algorithm. The data term of the energy function is expressed as a difference in visibility between each decomposed space and trajectory. The proposed method allows modeling of indoor spaces in complex environments, such as multi-room, room-less, and multi-level buildings. The performance of the proposed approach is evaluated for seven indoor space datasets.

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