The article doesn't say, but te method described in the article is called a notch filter. Here are some links on it, [0], [1], [2], [4]. Instead of cutting a sh

The article doesn't say, but te method described in the article is called a notch filter. Here are some links on it, [0], [1], [2], [4]. Instead of cutting a sharp edge on the frequency domain, it's better that the filter blur the edge to avoid introducing too much artifacts, and this is called a Gaussian notch filter. Anyway here is another method, that also targets peak regions on frequency domain for removal but is based on a median filter instead, [5] [0] Removal of Moiré Patterns in Frequency Domain, https://ijournals.in/wp-content/uploads/2017/07/5.3106-Khanjan.compressed.pdf https://ijournals.in/wp-content/uploads/2017/07/5.3106-Khanj... [1] Periodic Noise Removing Filter, https://docs.opencv.org/3.4.15/d2/d0b/tutorial_periodic_noise_removing_filter.html https://docs.opencv.org/3.4.15/d2/d0b/tutorial_periodic_nois... [3] Adaptive Gaussian notch filter for removing periodic noise from digital images, https://ietresearch.onlinelibrary.wiley.com/doi/10.1049/iet-ipr.2018.5707 https://ietresearch.onlinelibrary.wiley.com/doi/10.1049/iet-... [4] Adaptive Optimum Notch Filter for Periodic Noise Reduction in Digital Images, https://eej.aut.ac.ir/article_94_befd8a642325852c3a0d41ece10b3feb.pdf https://eej.aut.ac.ir/article_94_befd8a642325852c3a0d41ece10... [5] A New Method for Removing the Moire' Pattern from Images, https://arxiv.org/abs/1701.09037 https://arxiv.org/abs/1701.09037