2017-05-31 10:17:33 -0500 received badge ● Editor (source) 2017-05-31 10:16:24 -0500 asked a question Fast fourier higest three magnitudes i am trying to build a classifier using the fast Fourier as a feature for my image so the steps must be as following: 1-get the FFT coefficients 2-get the three highest magnitudes. 3-pass the highest magnitudes to a neural network classifier or k-nearest neighbor algorithm , the idea is that i don't know whether to use the coefficients or magnitudes , but any how here is the code i followed Mat padded; //expand input image to optimal size int m = getOptimalDFTSize(vertical.rows); int n = getOptimalDFTSize(vertical.cols); // on the border add zero values copyMakeBorder(vertical , padded, 0, m - vertical.rows, 0, n - vertical.cols, BORDER_CONSTANT, Scalar::all(0)); Mat planes[] = { Mat_(padded), Mat::zeros(padded.size(), CV_32F) }; Mat complexI; merge(planes, 2, complexI); // Add to the expanded another plane with zeros dft(complexI, complexI); // this way the result may fit in the source matrix split(complexI, planes); // planes = Re(DFT(I), planes = Im(DFT(I)) magnitude(planes, planes, planes);// planes = magnitude Mat magI = planes;  where Vertical is the required processed image ComplexI i guess is the FFT coefficients MagI is the Magnitude generally when using Matlab i would do : F=fft2(src); magnitude= abs(F); sorted_mag = sort(magnitude , 'descend') threehighest = sorted_mag(1:3);  then get these threehighest , put them into a vector and apply nearest neighbor. but hey that's matlab , so how do i implement this idea and code it in opencv c++ ?? please explain the concept behind the magnitude and how the dft is splited into planes ... 2017-05-01 18:30:23 -0500 commented answer How to remove line on music sheet I Have done this and worked with c++ code only with the same picture ... But when i tried some picture notes like these http://www.music-scores.com/midi.php?sheetmusic=Xmas_Deck_the_Hall_easy_piano (link text) the vertical picture doesn't show any notes ... so i figured out that the issue is in this line int verticalsize = vertical.rows/30 ;  changing 30 to bigger will create lower size and fix the image of notes but i quiet don't understand the concept of this line in general ... could you please explain it to me ?? 2017-03-25 11:54:47 -0500 commented question morphological operations in c# where can i find a help with c# ? 2017-03-25 11:43:50 -0500 asked a question morphological operations in c# i am sort of new to emgu in c# but i found these lines of code in c++ and i find it hard to translate it to c# Mat horizontalStructure = getStructuringElement(MORPH_RECT, Size(horizontalsize,1)); erode(horizontal, horizontal, horizontalStructure, Point(-1, -1)); dilate(horizontal, horizontal, horizontalStructure, Point(-1, -1));  basically i don't understand what Mat is ? and its difference other than creating Image horizontal; for example ... Anyhow i tried to do sort of this stuff but has always error and can't complete the last needed object call ... plus MORPH_RECT isn't located in the emgu c# or i can't find it at least... please help converting it to c# 2017-03-25 10:33:25 -0500 commented answer How to remove line on music sheet could you please provide more explanation on this code ? or explain how to write it in C#. // Create structure element for extracting vertical lines through morphology operations Mat verticalStructure = getStructuringElement(MORPH_RECT, Size( 1,verticalsize)); // Apply morphology operations erode(vertical, vertical, verticalStructure, Point(-1, -1)); dilate(vertical, vertical, verticalStructure, Point(-1, -1));  i understand that morphology operations are dilatation and erosion but i don't understand the usage of structure...?? and what is MORPH_REC .