Erratum for: Erratum for: Oil & Gas Science and Technology - Rev. IFP Energies nouvelles 76, 10 (2021) – https://doi.org/10.2516/ogst/2020086

Regarding the article “Identification of reservoir fractures on FMI image logs using Canny and Sobel edge detection algorithms, Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles 76, 10 (2021) – https://doi.org/10.2516/ogst/2020086”, published February 2nd, 2021, the authors have noticed that several errors occurred:

Equation (2) should read:$${\nabla }^{2}f\left(x,y\right)=\frac{{\partial }^{2}f(x,y)}{{\partial x}^2}+\frac{{\partial }^{2}f(x,y)}{{\partial y}^2}$$instead of:$${\nabla }^{2}f\left(\mathrm{xy}\right)=\frac{{\partial }^{2}f\left(\mathrm{xy}\right)}{{\partial x}^2}+\frac{{\partial }^{2}f\left(\mathrm{xy}\right)}{{\partial y}^2}$$

Equation (5) should read:$$\varphi (x,y)=\arctan (\mathrm{Gx}/\mathrm{Gy})$$instead of:$$\varphi (x.y)=\arctan (\mathrm{Gx}/\mathrm{Gy})$$

Equation (7) should read:$$\mathrm{NLM}\left(I\left(q\right)\right)=\sum _{{\forall }_qϵ\eta }w\left(p,q\right)I\left(q\right)$$instead of:$$\mathrm{NLM}\left(I\left(q\right)\right)=\sum _{{\forall }_qϵ\eta }w\left(p.q\right)I\left(q\right)$$

Equation (8) should read:$$0\le w\left(p,q\right)\le 1, \sum _{{\forall }_qϵ\mathrm{\eta }}w\left(p,q\right)=1$$instead of:$$0\le w\left(p.q\right)\le 1 . \sum _{{\forall }_qϵ\mathrm{\eta }}\left(p.q\right)=1$$

Equation (9) should read:$$w\left(p,q\right)=\frac{1}{z\left(p\right)}{e}^{-\left[\left(\frac{d\left(p,q\right)}{h^2}\right)\right]}$$instead of:$$w\left(p.q\right)=\frac{1}{z\left(p\right)}{e}^{-\left[\left(\frac{d\left(p.q\right)}{h^2}\right)\right]}$$

Equation (10) should read:$$z\left(p\right)=\sum _{\forall q}{e}^{-\left[\left(\frac{d\left(p,q\right)}{h^2}\right)\right]}$$instead of:$$z\left(p\right)=\sum _{\forall q}{e}^{-\left[\left(\frac{d\left(p.q\right)}{h^2}\right)\right]}$$

© M. Shafiabadi et al., published by IFP Energies nouvelles, 2021