Separability of three-dimensional geometric sensitivity correction in triple-headed gamma camera systems

2001 ◽  
Author(s):  
Yves D'Asseler ◽  
Stefaan Vandenberghe ◽  
Michel Koole ◽  
Luc Bouwens ◽  
Rik Van de Walle ◽  
...  
Keyword(s):  
Gamma Camera ◽  
Three Dimensional ◽  
Camera Systems

Calibration of gamma camera systems for a multicentre European 123I-FP-CIT SPECT normal database

2011 ◽  
Vol 38 (8) ◽  
pp. 1529-1540 ◽  
Author(s):  
Livia Tossici-Bolt ◽  
John C. Dickson ◽  
Terez Sera ◽  
Robin de Nijs ◽  
Maria Claudia Bagnara ◽  
...  
Keyword(s):  
Gamma Camera ◽  
Normal Database ◽  
Camera Systems

scholarly journals PCCT: A POINT CLOUD CLASSIFICATION TOOL TO CREATE 3D TRAINING DATA TO ADJUST AND DEVELOP 3D CONVNET

2019 ◽  
Vol XLII-2/W16 ◽  
pp. 35-40
Author(s):  
E. Barnefske ◽  
H. Sternberg
Keyword(s):  
Network Architecture ◽  
Point Cloud ◽  
Three Dimensional ◽  
Point Clouds ◽  
Classification Performance ◽  
Training Data ◽  
Process Step ◽  
Camera Systems ◽  
Classification Tool ◽  
Point Cloud Classification

<p><strong>Abstract.</strong> Point clouds give a very detailed and sometimes very accurate representation of the geometry of captured objects. In surveying, point clouds captured with laser scanners or camera systems are an intermediate result that must be processed further. Often the point cloud has to be divided into regions of similar types (object classes) for the next process steps. These classifications are very time-consuming and cost-intensive compared to acquisition. In order to automate this process step, conventional neural networks (ConvNet), which take over the classification task, are investigated in detail. In addition to the network architecture, the classification performance of a ConvNet depends on the training data with which the task is learned. This paper presents and evaluates the point clould classification tool (PCCT) developed at HCU Hamburg. With the PCCT, large point cloud collections can be semi-automatically classified. Furthermore, the influence of erroneous points in three-dimensional point clouds is investigated. The network architecture PointNet is used for this investigation.</p>

REAL-TIME MACHINE VISION SYSTEMS

1987 ◽  
Vol 41 (2) ◽  
pp. 173-180
Author(s):  
Kam W. Wong
Keyword(s):  
Solid State ◽  
Machine Vision ◽  
Real Time ◽  
Three Dimensional ◽  
The United States ◽  
Image Correlation ◽  
Software Systems ◽  
Vision Systems ◽  
Camera Systems ◽  
Recent Developments

Recent developments in machine vision systems, solid state cameras, and image processing are reviewed. Both hardware and software systems are currently available for performing real-time recognition and geometric measurements. More than 1000 units of these imaging systems are already being used in manufacturing plants in the United States. Current research efforts are focused on the processing of three-dimensional information and on knowledge-based processing systems. Five potential research topics in the area of photogrammetry are proposed: 1) stereo solid state camera systems, 2) image correlation, 3) self-calibration and self-orientation, 4) general algorithm for multistation and multicamera photography, and 5) artificial photogrammetry.

Position and Posture Measurement Method of the Omnidirectional Camera Using Identification Markers

2018 ◽  
Vol 30 (3) ◽  
pp. 354-362 ◽  
Author(s):  
Naoya Hatakeyama ◽  
◽  
Tohru Sasaki ◽  
Kenji Terabayashi ◽  
Masahiro Funato ◽  
...  
Keyword(s):  
Measurement Method ◽  
Position Control ◽  
Three Dimensional ◽  
Position Estimation ◽  
Position Measurement ◽  
Omnidirectional Camera ◽  
Camera Systems ◽  
Dimensional Measurements ◽  
Aerial Vehicle ◽  
Image Position

Recently, many studies on unmanned aerial vehicle (UAVs) that perform position control using camera images have been conducted. The measurements of the surrounding environment and position of the mobile robot are important in controlling the UAV. The distance and direction of the optical ray to the object can be obtained from the diameter and coordinates in the image. In these studies, various camera systems using plane cameras, fisheye cameras, or omnidirectional cameras are used. Because these camera systems have different geometrical optics, one simple image position measurement method cannot yield the position and posture. Therefore, we propose a new method that measures the position from the size of three-dimensional landmarks using omnidirectional cameras. Three-dimensional measurements are performed by these omnidirectional cameras using the distance and direction to the object. This method can measure three-dimensional positions from the direction and distance of the ray; therefore, if the optical path such as the reflection or refraction is known, it can perform measurements using a different optical system’s camera. In this study, we construct a method to obtain the relative position and relative posture necessary for the self-position estimation based on an object with an omnidirectional camera; further, we verify this method by experiment.

Effect of body posture on spatial distribution of pulmonary blood flow

1988 ◽  
Vol 64 (3) ◽  
pp. 1160-1170 ◽  
Author(s):  
T. S. Hakim ◽  
G. W. Dean ◽  
R. Lisbona
Keyword(s):  
Blood Flow ◽  
Central Region ◽  
Pulmonary Blood Flow ◽  
Gamma Camera ◽  
Single Photon ◽  
Regional Blood Flow ◽  
Photon Emission ◽  
Three Dimensional ◽  
Emission Computed Tomography ◽  
The Individual

Single-photon emission-computed tomography (SPECT) on intact dogs and humans suggests that one aspect of regional blood flow in the lung (Qr) is independent of gravity, e.g., the gradient in Qr between the core and the periphery. To further evaluate these findings, six anesthetized healthy dogs (approximately 30 kg), two in the supine posture, two in the prone posture, and two suspended in the upright posture, breathing spontaneously, were injected (iv) at end expiration with 20 mCi99mTc-labeled albumin macroaggregates. The animals were killed, their chests were opened, their lungs were removed and dissected free of other tissue, and the blood was drained. The lungs were dried by blowing warm air (50 degrees C) while they were inflated to full capacity for about 18 h. The fully inflated and dry lungs were placed in the supine position and SPECT was performed to determine the three-dimensional distribution of activity. One hundred and twenty projections of the activity in the entire lungs were obtained at 3 degrees steps with a rotating gamma camera and stored in computer memory. Once SPECT was completed, either a coronal slice or a sagittal slice (1 cm thick) was cut and imaged directly by placing it against the gamma camera collimator for 6 min. The tomographic-reconstructed slices revealed that at isogravity, in all body postures, Qr in the central region of the lungs was up to 10 times that in the periphery. Furthermore, the central-peripheral gradient was discernible within the individual lobes. The direct images of slices also confirmed these findings. Although flow inequalities independent of gravity were present, the central region with the highest flow often was closer to the dependent regions of the lungs, suggesting that gravity had some influence on the final distribution. The results suggest that factors other than gravity also play an important role in the distribution of pulmonary blood flow. These factors may be related to the conductance of the vascular pathways that lead to different regions in the lungs.

Sign in / Sign up

Export Citation Format

Share Document