Some pre-processing and post-processing strategies for improving the performance of planner R

2001 ◽  
Author(s):  
Chi-wai Chan
Keyword(s):  
Post Processing ◽  
Processing Strategies

scholarly journals Stable, Intelligible Ultrasonic Strain Imaging

Ultrasound ◽  
2008 ◽  
Vol 16 (4) ◽  
pp. 187-192 ◽  
Author(s):  
Andrew Gee ◽  
Joel Lindop ◽  
Graham Treece ◽  
Richard Prager ◽  
Susan Freeman
Keyword(s):  
Breast Biopsy ◽  
Signal To Noise Ratio ◽  
Strain Imaging ◽  
Time Averaging ◽  
Post Processing ◽  
Signal To Noise ◽  
Processing Strategies ◽  
Improved Stability ◽  
Noise Ratio

Background: Freehand quasistatic strain imaging can reveal qualitative information about tissue stiffness with good spatial accuracy. Clinical trials, however, repeatedly cite instability and variable signal-to-noise ratio as significant drawbacks. Methods: This study investigates three post-processing strategies for quasistatic strain imaging. Normalization divides the strain by an estimate of the stress field, the intention being to reduce sensitivity to variable applied stress. Persistence aims to improve the signal-to-noise ratio by time-averaging multiple frames. The persistence scheme presented in this article operates at the pixel level, weighting each frame's contribution by an estimate of the strain precision. Precision-based display presents the clinician with an image in which regions of indeterminate strain are obscured behind a colour wash. This is achieved using estimates of strain precision that are faithfully propagated through the various stages of signal processing. Results and discussion: The post-processing strategy is evaluated qualitatively on scans of a breast biopsy phantom and in vivo head and neck examinations. Strain images processed in this manner are observed to benefit from improved stability and signal-to-noise ratio. There are, however, limitations. In unusual though conceivable circumstances, the normalization procedure might suppress genuine stiffness variations evident in the unprocessed strain images. In different circumstances, the raw strain images might fail to capture significant stiffness variations, a situation that no amount of post-processing can improve. Conclusion: The clinical utility of freehand quasistatic strain imaging can be improved by normalization, precision-weighted pixel-level persistence and precision-based display. The resulting images are stable and generally exhibit a better signal-to-noise ratio than any of the original, unprocessed strain images.

scholarly journals Post-processing strategies in image scanning microscopy

Methods ◽  
2015 ◽  
Vol 88 ◽  
pp. 28-36 ◽  
Author(s):  
J.E. McGregor ◽  
C.A. Mitchell ◽  
N.A. Hartell
Keyword(s):  
Scanning Microscopy ◽  
Post Processing ◽  
Image Scanning ◽  
Processing Strategies

scholarly journals On the Influence of Laser Cladding and Post-processing Strategies on Residual Stresses in Steel Specimens

2014 ◽  
Vol 56 ◽  
pp. 250-261 ◽  
Author(s):  
H. Köhler ◽  
R. Rajput ◽  
P. Khazan ◽  
J. Rebelo Kornmeier
Keyword(s):  
Residual Stresses ◽  
Laser Cladding ◽  
Post Processing ◽  
Processing Strategies

MATLAB tools for the post-processing of GRACE temporal gravity field solutions

2020 ◽  
Author(s):  
Dimitrios Piretzidis ◽  
Michael Sideris
Keyword(s):  
Gravity Field ◽  
Land Surface ◽  
Optimal Strategies ◽  
Post Processing ◽  
Satellite Mission ◽  
Surface Mass ◽  
Isostatic Adjustment ◽  
Processing Strategies ◽  
Grace Data ◽  
Temporal Gravity

<p>We present a collection of MATLAB tools for the post-processing of temporal gravity field solutions from the Gravity Recovery and Climate Experiment (GRACE) satellite mission. GRACE final products are in the form of monthly sets of spherical harmonic coefficients and have been extensively used by the scientific community to study the land surface mass redistribution that is predominantly due to ice melting, glacial isostatic adjustment, seismic activity and hydrological phenomena. Since the launch of GRACE satellites, a substantial effort has been made to develop processing strategies and improve the surface mass change estimates.</p><p>The MATAB software presented in this work is developed and used by the Gravity and Earth Observation group at the department of Geomatics Engineering, University of Calgary. A variety of techniques and tools for the processing of GRACE data are implemented, tested and analyzed. Some of the software capabilities are: filtering of GRACE data using decorrelation and smoothing techniques, conversion of gravity changes into mass changes on the Earth’s spherical, ellipsoidal and topographical surface, implementation of forward modeling techniques for the estimation and removal of long-term trends due to ice mass melting, basin-specific spatial averaging in the spatial and spectral domain, time series smoothing and decomposition techniques, and data visualization.</p><p>All tools use different levels of parameterization in order to assist both expert users and non-specialists. Such a software makes the comparison between different GRACE processing methods and parameters used easier, leading to optimal strategies for the estimation of surface mass changes and to the standardization of GRACE data post-processing. It could also facilitate the use of GRACE data to non-geodesists.</p>

scholarly journals Machining and heat treatment as post-processing strategies for Ni-superalloys structures fabricated using direct energy deposition

2021 ◽  
Vol 61 ◽  
pp. 236-244
Author(s):  
Francesco Careri ◽  
Stano Imbrogno ◽  
Domenico Umbrello ◽  
Moataz M. Attallah ◽  
José Outeiro ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Energy Deposition ◽  
Post Processing ◽  
Direct Energy Deposition ◽  
Processing Strategies ◽  
Direct Energy

scholarly journals Coastal Mapping Using DJI Phantom 4 RTK in Post-Processing Kinematic Mode

Drones ◽  
2020 ◽  
Vol 4 (2) ◽  
pp. 9 ◽  
Author(s):  
Yuri Taddia ◽  
Francesco Stecchi ◽  
Alberto Pellegrinelli
Keyword(s):  
Ease Of Use ◽  
Reference Station ◽  
Post Processing ◽  
Coastal Mapping ◽  
Digital Terrain ◽  
Ground Control Points ◽  
Processing Strategies ◽  
Camera Location ◽  
Aerial Mapping ◽  
Oblique Images

Topographic and geomorphological surveys of coastal areas usually require the aerial mapping of long and narrow sections of littoral. The georeferencing of photogrammetric models is generally based on the signalization and survey of Ground Control Points (GCPs), which are very time-consuming tasks. Direct georeferencing with high camera location accuracy due to on-board multi-frequency GNSS receivers can limit the need for GCPs. Recently, DJI has made available the Phantom 4 Real-Time Kinematic (RTK) (DJI-P4RTK), which combines the versatility and the ease of use of previous DJI Phantom models with the advantages of a multi-frequency on-board GNSS receiver. In this paper, we investigated the accuracy of both photogrammetric models and Digital Terrain Models (DTMs) generated in Agisoft Metashape from two different image datasets (nadiral and oblique) acquired by a DJI-P4RTK. Camera locations were computed with the Post-Processing Kinematic (PPK) of the Receiver Independent Exchange Format (RINEX) file recorded by the aircraft during flight missions. A Continuously Operating Reference Station (CORS) located at a 15 km distance from the site was used for this task. The results highlighted that the oblique dataset produced very similar results, with GCPs (3D RMSE = 0.025 m) and without (3D RMSE = 0.028 m), while the nadiral dataset was affected more by the position and number of the GCPs (3D RMSE from 0.034 to 0.075 m). The introduction of a few oblique images into the nadiral dataset without any GCP improved the vertical accuracy of the model (Up RMSE from 0.052 to 0.025 m) and can represent a solution to speed up the image acquisition of nadiral datasets for PPK with the DJI-P4RTK and no GCPs. Moreover, the results of this research are compared to those obtained in RTK mode for the same datasets. The novelty of this research is the combination of a multitude of aspects regarding the DJI Phantom 4 RTK aircraft and the subsequent data processing strategies for assessing the quality of photogrammetric models, DTMs, and cross-section profiles.

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