Design of a Calibration Phantom for Measuring the Temporal Resolution of a Tomographic Imaging Device

2007 ◽  
Vol 1 (3) ◽  
pp. 225-232
Author(s):  
Alexander H. Slocum ◽  
Stephen E. Jones ◽  
Rajiv Gupta
Keyword(s):  
Spatial Resolution ◽  
Temporal Resolution ◽  
Planetary Gear ◽  
Tomographic Imaging ◽  
Spatial Modulation ◽  
Acquisition Time ◽  
Input Frequency ◽  
Modulation Transfer ◽  
Imaging Device ◽  
Calibration Phantom

This paper describes the design and development of a calibration phantom to be used to aid in the calculation of the temporal resolution of tomographic imaging devices. Current practice for characterizing the dynamic response of a tomographic imaging device, such as a computed tomography or magnetic resonance imaging machine, uses image acquisition time as a surrogate for temporal resolution. At present, no standard method for describing the temporal resolution of a tomographic imaging device exists. Similar to the spatial modulation transfer function (MTF) used for characterizing spatial resolution, the concept of temporal MTF (t-MTF) can be used to enable characterization of temporal resolution. A scanner’s t-MTF represents the percentage amplitude modulation transfer in the image as a function of the input frequency. The calibration phantom uses slotted disks, each mounted to the rotating ring gear of a planetary gear assembly. The sun gears of each planetary gear set are driven from a common shaft to create differential speed sectors, allowing for about two decades of input frequencies to be obtained using a single motor and driveshaft. Preliminary results show a monotonic decline in the modulation transfer as the input frequency is increased. As expected, there is more modulation transfer at lower frequency and less modulation transfer at high frequency. Analogous to the spatial resolution, one can define the frequency for which there is 10% modulation transfer as the temporal resolution of a scanner.

scholarly journals Temporal Resolution Phantom: A Device and Method for Measurement of a CT Scanner’s Temporal Resolution

2008 ◽  
Vol 2 (2) ◽  
Author(s):  
Alexander H. Slocum ◽  
Stephen E. Jones ◽  
Rajiv Gupta
Keyword(s):  
Temporal Resolution ◽  
Imaging Modality ◽  
Temporal Frequency ◽  
Planetary Gear ◽  
Multiple Time ◽  
Functional Requirements ◽  
Ct Scanner ◽  
Calibration Phantom ◽  
Wide Range ◽  
Further Development

A calibration phantom that can be used to measure the temporal resolution of a CT scanner was designed utilizing a deterministic design process. The system was first defined in terms of a set of functional requirements based on parameters of the imaging modality. It was necessary to generate multiple time-varying signals visible to the scanner, each with a pre-determined temporal frequency. Roll-off in the scanner’s ability to resolve the modulation of certain signals would be used to determine the scanner’s temporal resolution. Based on size limitations imposed by the scanning environment, the phantom utilizes multiple planetary gear assemblies, driven by a common shaft, to achieve a wide range of rotational velocities. Results obtained with an alpha prototype agreed with the theory. It was determined that further development of the phantom was necessary to increase the sensitivity of the measurement. The latest prototype phantom has been used to measure the temporal resolution of two different scanners and it was shown that temporal resolution of each is different from the gantry rotation time.

scholarly journals Employing temporal self-similarity across the entire time domain in computed tomography reconstruction

2015 ◽  
Vol 373 (2043) ◽  
pp. 20140389 ◽  
Author(s):  
D. Kazantsev ◽  
G. Van Eyndhoven ◽  
W. R. B. Lionheart ◽  
P. J. Withers ◽  
K. J. Dobson ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Spatial Resolution ◽  
Temporal Resolution ◽  
Imaging Modality ◽  
Time Lapse ◽  
Frame Rate ◽  
Acquisition Time ◽  
Dynamic Features ◽  
Penalty Term ◽  
Computational Performance

There are many cases where one needs to limit the X-ray dose, or the number of projections, or both, for high frame rate (fast) imaging. Normally, it improves temporal resolution but reduces the spatial resolution of the reconstructed data. Fortunately, the redundancy of information in the temporal domain can be employed to improve spatial resolution. In this paper, we propose a novel regularizer for iterative reconstruction of time-lapse computed tomography. The non-local penalty term is driven by the available prior information and employs all available temporal data to improve the spatial resolution of each individual time frame. A high-resolution prior image from the same or a different imaging modality is used to enhance edges which remain stationary throughout the acquisition time while dynamic features tend to be regularized spatially. Effective computational performance together with robust improvement in spatial and temporal resolution makes the proposed method a competitive tool to state-of-the-art techniques.

scholarly journals Deep-Learning Super-Resolution Microscopy Reveals Nanometer-Scale Intracellular Dynamics at the Millisecond Temporal Resolution

2021 ◽  
Author(s):  
Rong Chen ◽  
Xiao Tang ◽  
Zeyu Shen ◽  
Yusheng Shen ◽  
Tiantian Li ◽  
...  
Keyword(s):  
Deep Learning ◽  
Spatial Resolution ◽  
Temporal Resolution ◽  
Single Molecule ◽  
Super Resolution ◽  
Live Cell ◽  
Acquisition Time ◽  
Microtubule Network ◽  
Single Frame ◽  
Super Resolution Microscopy

AbstractSingle-molecule localization microscopy (SMLM) can be used to resolve subcellular structures and achieve a tenfold improvement in spatial resolution compared to that obtained by conventional fluorescence microscopy. However, the separation of single-molecule fluorescence events in thousands of frames dramatically increases the image acquisition time and phototoxicity, impeding the observation of instantaneous intracellular dynamics. Based on deep learning networks, we develop a single-frame super-resolution microscopy (SFSRM) approach that reconstructs a super-resolution image from a single frame of a diffraction-limited image to support live-cell super-resolution imaging at a ∼20 nm spatial resolution and a temporal resolution of up to 10 ms over thousands of time points. We demonstrate that our SFSRM method enables the visualization of the dynamics of vesicle transport at a millisecond temporal resolution in the dense and vibrant microtubule network in live cells. Moreover, the well-trained network model can be used with different live-cell imaging systems, such as confocal and light-sheet microscopes, making super-resolution microscopy accessible to nonexperts.

Fault Localization and Functional Testing of ICs by Lock-in Thermography

2002 ◽  
Author(s):  
O. Breitenstein ◽  
J.P. Rakotoniaina ◽  
F. Altmann ◽  
J. Schulz ◽  
G. Linse
Keyword(s):  
Spatial Resolution ◽  
Electronic Device ◽  
Imaging Techniques ◽  
Heat Diffusion ◽  
Acquisition Time ◽  
Temperature Modulation ◽  
Heat Sources ◽  
Ir Camera ◽  
Free Running ◽  
Lock In

Abstract In this paper new thermographic techniques with significant improved temperature and/or spatial resolution are presented and compared with existing techniques. In infrared (IR) lock-in thermography heat sources in an electronic device are periodically activated electrically, and the surface is imaged by a free-running IR camera. By computer processing and averaging the images over a certain acquisition time, a surface temperature modulation below 100 µK can be resolved. Moreover, the effective spatial resolution is considerably improved compared to stead-state thermal imaging techniques, since the lateral heat diffusion is suppressed in this a.c. technique. However, a serious limitation is that the spatial resolution is limited to about 5 microns due to the IR wavelength range of 3 -5 µm used by the IR camera. Nevertheless, we demonstrate that lock-in thermography reliably allows the detection of defects in ICs if their power exceeds some 10 µW. The imaging can be performed also through the silicon substrate from the backside of the chip. Also the well-known fluorescent microthermal imaging (FMI) technique can be be used in lock-in mode, leading to a temperature resolution in the mK range, but a spatial resolution below 1 micron.

A four-channel ICCD framing camera with nanosecond temporal resolution and high spatial resolution

2021 ◽  
pp. 1-9
Author(s):  
Yuman Fang ◽  
Minrui Zhang ◽  
Junfeng Wang ◽  
Lehui Guo ◽  
Xueling Liu ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Temporal Resolution ◽  
High Spatial Resolution ◽  
Framing Camera

scholarly journals Temporal load resolution impact on PV/grid system energy flows

2018 ◽  
Vol 240 ◽  
pp. 04003 ◽  
Author(s):  
Marek Jaszczur ◽  
Qusay Hassan ◽  
Janusz Teneta
Keyword(s):  
Temporal Resolution ◽  
System Analysis ◽  
Estimation Error ◽  
Energy System ◽  
Photovoltaic System ◽  
Acquisition Time ◽  
Storage Unit ◽  
Time Step ◽  
Energy Flows ◽  
Pv Grid

In this paper, an investigation of the electrical load temporal resolution on the PV/Grid energy system flows, and self-consumption is done in order to determine the optimum parameters for modelling and simulation. The analysed PV/Grid power systems include a photovoltaic system with the nominal power of Pmax@STC=1.5, 2.5, 3.5 kW without storage unit connected to the grid. The results show that the temporal load resolution may have a high impact on energy flows as well as can be a critical issue for the system analysis accuracy even for the single household. It has been found that the load temporal resolution for energy consumption of 1-min yields reliable results, while data resolutions of 5 and 15 min are still sufficient, however, in that case, the daily electrical energy flows and in consequence energy self-consumption estimation error for selected days may exceed 15%. Acquisition time step longer than 15-minutes may increase error above 20% and from the designer’s point of view should not be used. The high and low temporal resolution experimental data of the electricity consumption (load) for a household are available in digital form on the author’s website http://home.agh.edu.pl/jaszczur.

scholarly journals Super-resolution time-resolved imaging using computational sensor fusion

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
C. Callenberg ◽  
A. Lyons ◽  
D. den Brok ◽  
A. Fatima ◽  
A. Turpin ◽  
...  
Keyword(s):  
Sensor Fusion ◽  
Spatial Resolution ◽  
Temporal Resolution ◽  
Single Photon ◽  
Super Resolution ◽  
Numerical Data ◽  
Data Cube ◽  
Fluorescence Lifetime Imaging ◽  
Time Resolved ◽  
Temporal Precision

AbstractImaging across both the full transverse spatial and temporal dimensions of a scene with high precision in all three coordinates is key to applications ranging from LIDAR to fluorescence lifetime imaging. However, compromises that sacrifice, for example, spatial resolution at the expense of temporal resolution are often required, in particular when the full 3-dimensional data cube is required in short acquisition times. We introduce a sensor fusion approach that combines data having low-spatial resolution but high temporal precision gathered with a single-photon-avalanche-diode (SPAD) array with data that has high spatial but no temporal resolution, such as that acquired with a standard CMOS camera. Our method, based on blurring the image on the SPAD array and computational sensor fusion, reconstructs time-resolved images at significantly higher spatial resolution than the SPAD input, upsampling numerical data by a factor $$12 \times 12$$ 12 × 12 , and demonstrating up to $$4 \times 4$$ 4 × 4 upsampling of experimental data. We demonstrate the technique for both LIDAR applications and FLIM of fluorescent cancer cells. This technique paves the way to high spatial resolution SPAD imaging or, equivalently, FLIM imaging with conventional microscopes at frame rates accelerated by more than an order of magnitude.

Investigation of Local Dynamics on the Sub-micron Scale in Organic Blends Using an Ultrafast Confocal Microscope

2010 ◽  
Vol 1270 ◽  
Author(s):  
Giulia Grancini ◽  
Dario Polli ◽  
Jenny Clark ◽  
Tersilla Virgili ◽  
Giulio Cerullo ◽  
...  
Keyword(s):  
Excited State ◽  
Confocal Microscopy ◽  
Polymer Blends ◽  
Spatial Resolution ◽  
Temporal Resolution ◽  
Electronic States ◽  
Pump Probe ◽  
Peculiar Behaviour ◽  
Spatio Temporal ◽  
Probe Spectroscopy

AbstractWe introduce a novel instrument combining femtosecond pump-probe spectroscopy and confocal microscopy for spatio-temporal imaging of excited-state dynamics of phase-separated polymer blends. Phenomena occurring at interfaces between different materials are crucial for optimizing the device performances, but are poorly understood due to the variety of possible electronic states and processes involved and to their complicated dynamics. Our instrument (with 200-fs temporal resolution and 300-nm spatial resolution) provides new insights into the properties of polymer blends, revealing spatially variable photo-relaxation paths and dynamics and highlighting a peculiar behaviour at the interface between the phase-separated domains.

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