Gradient Directional Second Derivative Pseudo-enhancement Correction and Modified Local Roughness Response Estimation for Electronic Cleansing in CT Colonography

2018 ◽  
Vol 38 (5) ◽  
pp. 757-773
Author(s):  
Krisorn Chunhapongpipat ◽  
Ratinan Boonklurb ◽  
Bundit Chaopathomkul ◽  
Sirod Sirisup ◽  
Rajalida Lipikorn
2008 ◽  
Vol 41 (15) ◽  
pp. 41
Author(s):  
HEIDI SPLETE
Keyword(s):  

Endoscopy ◽  
2004 ◽  
Vol 36 (05) ◽  
Author(s):  
RJT Sadleir ◽  
PF Whelan ◽  
N Sezille ◽  
TA Chowdhury ◽  
A Moss ◽  
...  

2005 ◽  
Vol 52 (1) ◽  
pp. 15 ◽  
Author(s):  
Yoon Kyung Kim ◽  
Ji Eun Lee ◽  
Jeong Kyung Lee ◽  
Seung Yon Baek ◽  
Hyun Ju Song ◽  
...  
Keyword(s):  

1994 ◽  
Vol 86 (2) ◽  
pp. 349-354 ◽  
Author(s):  
Haiping Su ◽  
Michel D. Ransom ◽  
Edward T. Kanemasu ◽  
Tanvir H. Demetriades‐Shah

2017 ◽  
Vol 919 (1) ◽  
pp. 7-12
Author(s):  
N.A Sorokin

The method of the geopotential parameters determination with the use of the gradiometry data is considered. The second derivative of the gravitational potential in the correction equation on the rectangular coordinates x, y, z is used as a measured variable. For the calculated value of the measured quantity required for the formation of a free member of the correction equation, the the Cunningham polynomials were used. We give algorithms for computing the second derivatives of the Cunningham polynomials on rectangular coordinates x, y, z, which allow to calculate the second derivatives of the geopotential at the rectangular coordinates x, y, z.Then we convert derivatives obtained from the Cartesian coordinate system in the coordinate system of the gradiometer, which allow to calculate the free term of the correction equation. Afterwards the correction equation coefficients are calculated by differentiating the formula for calculating the second derivative of the gravitational potential on the rectangular coordinates x, y, z. The result is a coefficient matrix of the correction equations and corrections vector of the free members of equations for each component of the tensor of the geopotential. As the number of conditional equations is much more than the number of the specified parameters, we go to the drawing up of the system of normal equations, from which solutions we determine the required corrections to the harmonic coefficients.


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