Phase Only Correlation - AForge

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using AForge;
using AForge.Imaging;                  
using AForge.Imaging.ComplexFilters;    // for FFT
using AForge.Imaging.Filters;           // for Smoothing
using AForge.Math;

namespace winForm1
{
    public partial class Form1 : Form
    {

        Bitmap image;       // Global Bitmap
        Bitmap image2;

        private bool _drawRect = false;
        private bool _drawCircle = false;

        public Form1()
        {
            InitializeComponent();
            pictureBox1.Paint += new PaintEventHandler(this.pictureBox1_Paint);

            // load image
            image =
                AForge.Imaging.Image.FromFile(@"C:\Users\user\Pictures\tiger22.png");
            image2 =
                AForge.Imaging.Image.FromFile(@"C:\Users\user\Pictures\tiger22.png");

        }

        // Calc FFT2 when button --------------------------------------------
        private void button1_Click(object sender, EventArgs e)
        {
            // create complex image
            ComplexImage complexImage = ComplexImage.FromBitmap(image);
            // do forward Fourier transformation
            complexImage.ForwardFourierTransform();
            // get complex image as bitmat
            Bitmap fourierImage = complexImage.ToBitmap();

            pictureBox1.Image = fourierImage;
        }

        // show Original Image --------------------------------------------
        private void Form1_Load(object sender, EventArgs e)
        {
            pictureBox2.Image = image;
            pictureBox1.Image = image2;

            pictureBox1.SizeMode = PictureBoxSizeMode.Zoom;
            pictureBox2.SizeMode = PictureBoxSizeMode.Zoom;
            pictureBox3.SizeMode = PictureBoxSizeMode.Zoom;
        }

        // form exit ------------------------------------------------------
        private void button2_Click(object sender, EventArgs e)
        {
            this.Close();
        }

        // circle drawing button ------------------------------------------
        private void button3_Click(object sender, EventArgs e)
        {
            _drawRect = false;
            _drawCircle = true;

            pictureBox1.Invalidate();

            MessageBox.Show("Good~!");
        }

        // picBox Paint event ------------------------------------------------
        private void pictureBox1_Paint(object sender, PaintEventArgs e)
        {
            if (_drawRect){
                Graphics g = e.Graphics;
                // use g to do your drawing
                Rectangle rect = new Rectangle(100, 100, 10, 10);
                e.Graphics.DrawRectangle(new Pen(Color.Green, 20), rect);
            }
            if (_drawCircle)
            {
                Graphics g = e.Graphics;
                // use g to do your drawing
                Rectangle rect = new Rectangle(108, 108, 40, 40);
                e.Graphics.DrawEllipse(new Pen(Color.Red, 1), rect);
            }
        }

        // Calc LPF with FFT2 ----------------------------------------------
        private void button4_Click(object sender, EventArgs e)
        {
            // create complex image
            ComplexImage complexImage = ComplexImage.FromBitmap(image);
            // do forward Fourier transformation
            complexImage.ForwardFourierTransform();
            // create filter
            FrequencyFilter filter = new FrequencyFilter(new IntRange(0, 20));
            // apply filter
            filter.Apply(complexImage);
            // do backward Fourier transformation
            complexImage.BackwardFourierTransform();
            // get complex image as bitmat
            Bitmap fourierImage = complexImage.ToBitmap();

            // create filter
            HistogramEqualization filter2 = new HistogramEqualization();
            // process image
            filter2.ApplyInPlace(fourierImage);

            pictureBox1.Image = fourierImage;
        }// button4

        // Calc POC ------------------------------------------------------
        private void button5_Click(object sender, EventArgs e)
        {
            // 이미지들 로드
            Bitmap fix1 = (Bitmap)pictureBox2.Image;
            Bitmap shift1 = (Bitmap)pictureBox1.Image;

            // 그레이 이미지화.
            fix1 = Grayscale.CommonAlgorithms.BT709.Apply(fix1) ;
            shift1 = Grayscale.CommonAlgorithms.BT709.Apply(shift1);

            //pictureBox1.Image = fix1;
            //pictureBox2.Image = shift1;

            // 복소 이미지버퍼화.
            ComplexImage fixedCplx = ComplexImage.FromBitmap(fix1) ;
            int height = fixedCplx.Data.GetLength(0);
            int width = fixedCplx.Data.GetLength(1);
            ComplexImage shiftedCplx = ComplexImage.FromBitmap(shift1);
            //
            ComplexImage SonCplx = ComplexImage.FromBitmap(shift1);
            ComplexImage MomCplx = ComplexImage.FromBitmap(shift1);

            // 2D FFT
            fixedCplx.ForwardFourierTransform();
            shiftedCplx.ForwardFourierTransform();

            //pictureBox1.Image = fixedCplx.ToBitmap();

            // 복소영상의 모든 픽셀에 대해.
            for (int y = 0; y < height; y++)
            {
                for (int x = 0; x < width; x++)
                {
                    //Calculating elementwise complex conjugate of the
                    //shifted image 2d vector
                    // 복소공액 영상 계산
                    shiftedCplx.Data[y, x].Im = -1 * shiftedCplx.Data[y, x].Im;
                    //Elementwise multiplication to obtain cross power spectrum
                    // 푸리에 분자곱
                    SonCplx.Data[y, x].Re =
                        fixedCplx.Data[y, x].Re * shiftedCplx.Data[y, x].Re -
                        fixedCplx.Data[y, x].Im * shiftedCplx.Data[y, x].Im;

                    SonCplx.Data[y, x].Im =
                        fixedCplx.Data[y, x].Re * shiftedCplx.Data[y, x].Im +
                        shiftedCplx.Data[y, x].Re * fixedCplx.Data[y, x].Im;

                    // 이미지를  F × G *
                    //dstRe[i, j] = srcRe1[i, j] * srcRe2[i, j] - srcIm1[i, j] * srcIm2[i, j];
                    //dstIm[i, j] = srcRe1[i, j] * srcIm2[i, j + srcRe2[i, j] * srcIm1[i, j];
                }
            }

            double Spectrum = 0;

            // 복소영상의 모든 픽셀에 대해.
            for (int y = 0; y < height; y++)
            {
                for (int x = 0; x < width; x++)
                {
                    //Elementwise normalization
                    Spectrum = Math.Sqrt(SonCplx.Data[y, x].Re *
                        SonCplx.Data[y, x].Re +
                        SonCplx.Data[y, x].Im * SonCplx.Data[y, x].Im);
                    // 푸리에 분자곱 나누기 분모곱 절대값
                    MomCplx.Data[y, x].Re =
                        SonCplx.Data[y, x].Re / Spectrum;
                    MomCplx.Data[y, x].Im =
                        SonCplx.Data[y, x].Im / Spectrum;
                    // 절대 값을 계산하고 그 값으로 나누면 | F × G * |
                    //double Spectrum = Math.Sqrt(dstRe[i, j] * dstRe[i, j] + dstIm[i, j] * dstIm[i, j]);
                    //dstRe[i, j] = dstRe[i, j] / spectrum;
                    //dstIm[i, j] = dstIm[i, j] / spectrum;
                }
            }
            // 푸리에 역변환.
            //MomCplx.BackwardFourierTransform();
            MomCplx.ForwardFourierTransform();

            // get complex image as bitmat
            Bitmap bmpFour = MomCplx.ToBitmap();

            // Brighten filter
            //BrightnessCorrection filter = new BrightnessCorrection(5);
            // apply the filter
            //filter.ApplyInPlace(fourierImage);

            // Median filter
            //GaussianBlur filter = new GaussianBlur();
            // apply the filter
            //filter.ApplyInPlace(bmpFour);

            pictureBox3.Image = bmpFour;

            MessageBox.Show("IFFT, Success~");

            // collect statistics
            ImageStatistics his =
                new ImageStatistics(bmpFour);
            // get gray histogram (for grayscale image)
            Histogram histogram = his.Gray;

            MessageBox.Show("Gray Max = " + histogram.Max.ToString());
        }
    }// class Form1
}// namespace