scholarly journals Modulation transfer function evaluation of cone beam computed and microcomputed tomography by using slanted edge phantom

2019 ◽  
Author(s):  
Szabó TAMÁS BENCE
Keyword(s):  
Transfer Function ◽  
Spatial Resolution ◽  
Modulation Transfer Function ◽  
Imaging System ◽  
Ct Images ◽  
Function Evaluation ◽  
Strong Positive Correlation ◽  
Micro Ct ◽  
Modulation Transfer ◽  
Voxel Size

Modulation transfer function (MTF) is a well known and widely accepted method for evaluating the spatial resolution of a digital radiographic imaging system. In the present study our aim was to evaluate the MTF obtained from CBCT and micro-CT images. A cylinder shaped phantom designed for slanted-edge method was scanned by a CBCT device at a 100 µm isometric voxel size and by a micro-CT device at a 20 µm isometric voxel size, simultaneously. The MTF curves were calculated and the mean spatial resolutions at 10% MTF were 3.33 + 0.29 lp/mm in the case of CBCT images and 13.35 + 2.47 lp/mm in the case of micro-CT images. The values showed a strong positive correlation regarding the CBCT and the micro-CT spatial resolution values, respectively. Our results suggests that CBCT imaging devices with a voxel size of 100 µm or below might aid the validation of fine anatomical structures and allowing the opportunity for reliable micromorphometric examinations

Modulation Transfer Function Evaluation of a Hadamard Transform Photothermal Deflection Imaging System with Beam Condensing Optics

1988 ◽  
Vol 42 (8) ◽  
pp. 1487-1493 ◽  
Author(s):  
Patrick J. Treado ◽  
Michael D. Morris
Keyword(s):  
Transfer Function ◽  
Modulation Transfer Function ◽  
Imaging System ◽  
Function Evaluation ◽  
Hadamard Transform ◽  
Modulation Transfer ◽  
Photothermal Deflection

The modulation transfer function of a source-encoded Hadamard transform imaging system including beam condensing optics is derived. The effects of diffraction, convolution with the encoding apertures, mask motion, and focus errors are considered explicitly. The derived equations are shown to describe resolution of Hadamard transform photothermal deflection imagers with up to 30 × condensing optics.

scholarly journals Comparison of MTF Measurement Methods in CT Images for Various Reconstruction Kernels

2021 ◽  
pp. 396-405
Author(s):  
Fakhri Ramadhani Arisyi ◽  
Choirul Anam ◽  
Catur Edi Widodo
Keyword(s):  
Transfer Function ◽  
Spatial Resolution ◽  
Modulation Transfer Function ◽  
Copper Wire ◽  
Ct Images ◽  
Measurement Methods ◽  
Point Method ◽  
Modulation Transfer ◽  
Circular Object

This study aimed to compare several methods of measuring the modulation transfer function (MTF) for different reconstruction kernels, using a point phantom, a small-circular (S-circular) Teflon object, and the automated edge of a PMMA phantom. The copper wire section of a phantom was used for the point method. The small-circular (S-circular) teflon object within the HU linearity section was used for measuring MTF using ImQuest software. The automated edge of a PMMA phantom was used to automatically measure the MTF. The three methods were implemented in images reconstructed with ten different kernels. It was found that the three methods produced comparable MTFs for all the kernels used. However, the automated edge of the PMMA phantom produced slightly smaller spatial resolutions compared with the two other methods. The differences between the automated edge of PMMA and the point method were small, i.e. 0.04 cycle/mm for both 10% MTF and 50% MTF. The differences between the automated edge of PMMA and the S-circular phantom were 0.05 cycle/mm and 0.03 cycle/mm for 10% MTF and 50% MTF. We found that the “UA” kernel produced the lowest spatial resolution values of 0.32, 0.33, and 0.31 cycle/mm of 50% MTF for point, S-circular object, and automated edge PMMA, respectively. The “YD” produced the highest spatial resolution values of 0.78, 0.76, and 0.67 cycle/mm of 10% MTF for point, S-circular object, and automated edge PMMA, respectively. We successfully compared three methods of MTF measurement. The three methods produce comparable MTFs, so that each method can be used for accurately measuring MTF depending on phantom and software available in the CT center.

Imaging

2019 ◽  
pp. 382-434
Author(s):  
B. D. Guenther
Keyword(s):  
Transfer Function ◽  
Modulation Transfer Function ◽  
Noise Intensity ◽  
Imaging System ◽  
Optical Transfer Function ◽  
Modulation Transfer ◽  
Optical Aperture ◽  
System Properties ◽  
Incoherent Imaging ◽  
Optical Transfer

Treating an imaging system as a linear system and use llinear system properties to d iscuss both coherent and incoherent imaging. Use a one dimensional pin hole camera to study the theory of incoherent imaging. Two different criteria, Rayleigh and Sparrow, are used to define the resolution limits of the camera. From the simple theory define the optical transfer function and the modulation transfer function as appropriate characterizations of complex imaging systems. A review of the human imaging system emphasizes tits idfferences with man made cameras. Coherent imaging is based on Abbe’s theory of microscopy. A simple 4f imaging system can be used to understand how spatial resolution is limited by the optical aperture and by controlling the aperture, we can enhance the edges of an image or remove noise intensity noise on a plane wave. Apodizing the aperture allows astronomers to locate planents orbiting distant stars.

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