Download - Image fft
![Page 1: Image fft](https://reader033.vdocuments.us/reader033/viewer/2022061201/5479895fb4af9f4f328b4607/html5/thumbnails/1.jpg)
Image Fourier Transform
![Page 2: Image fft](https://reader033.vdocuments.us/reader033/viewer/2022061201/5479895fb4af9f4f328b4607/html5/thumbnails/2.jpg)
![Page 3: Image fft](https://reader033.vdocuments.us/reader033/viewer/2022061201/5479895fb4af9f4f328b4607/html5/thumbnails/3.jpg)
![Page 4: Image fft](https://reader033.vdocuments.us/reader033/viewer/2022061201/5479895fb4af9f4f328b4607/html5/thumbnails/4.jpg)
![Page 5: Image fft](https://reader033.vdocuments.us/reader033/viewer/2022061201/5479895fb4af9f4f328b4607/html5/thumbnails/5.jpg)
![Page 6: Image fft](https://reader033.vdocuments.us/reader033/viewer/2022061201/5479895fb4af9f4f328b4607/html5/thumbnails/6.jpg)
![Page 7: Image fft](https://reader033.vdocuments.us/reader033/viewer/2022061201/5479895fb4af9f4f328b4607/html5/thumbnails/7.jpg)
![Page 8: Image fft](https://reader033.vdocuments.us/reader033/viewer/2022061201/5479895fb4af9f4f328b4607/html5/thumbnails/8.jpg)
• >> I1=imread('lines1.png');• >> imshow(I1);• >> A1=fft2(I1);• >> A2=fftshift(A1);• >> imshow(A2);
![Page 9: Image fft](https://reader033.vdocuments.us/reader033/viewer/2022061201/5479895fb4af9f4f328b4607/html5/thumbnails/9.jpg)
fft transform for the strip lines image
![Page 10: Image fft](https://reader033.vdocuments.us/reader033/viewer/2022061201/5479895fb4af9f4f328b4607/html5/thumbnails/10.jpg)
Original image
![Page 11: Image fft](https://reader033.vdocuments.us/reader033/viewer/2022061201/5479895fb4af9f4f328b4607/html5/thumbnails/11.jpg)
• I1=imread('lines1.png');• figure(1), imshow(I1);• A1=fft2(I1);• A2=fftshift(A1);• figure(2),imshow(A2);• • [m,n]=size(A2);• • %%%%%%%%%%%%%%%%%%%%%%%%%%%%%Here we retrieve part of the image fourier• %%%%%%%%%%%%%%%%%%%%%%%%%%%%%coefficients%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%• %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%• • A3=A2(0.4*m:m,0.4*n:n);• • figure(3),imshow(uint8(ifft2(A3)));• • title('Restructuring the image after removing some fourier coefficients');
![Page 12: Image fft](https://reader033.vdocuments.us/reader033/viewer/2022061201/5479895fb4af9f4f328b4607/html5/thumbnails/12.jpg)
![Page 13: Image fft](https://reader033.vdocuments.us/reader033/viewer/2022061201/5479895fb4af9f4f328b4607/html5/thumbnails/13.jpg)
A3=A2(0.4*m:m,0.4*n:n); figure(3),imshow(uint8(abs((ifft2(A3))))); title('Restructuring the image after removing some fourier coefficients');
![Page 14: Image fft](https://reader033.vdocuments.us/reader033/viewer/2022061201/5479895fb4af9f4f328b4607/html5/thumbnails/14.jpg)
• close all,clear all,clc• I1=imread('lines2.png');• figure(1), imshow(I1);• A1=fft2(I1);• A2=fftshift(A1);• [m,n]=size(A2);• nn=max(max(A2));• for i=1:m• for j=1:n• if A2(i,j)==nn• l=i• p=j• end• end• end• xx=(A2==nn);• figure(2),imshow(A2);• • [m,n]=size(A2);• • %%%%%%%%%%%%%%%%%%%%%%%%%%%%%Here we retrieve part of the image fourier• %%%%%%%%%%%%%%%%%%%%%%%%%%%%%coefficients%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%• %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%• • A3=A2(0.45*m:m,0.45*n:n);• • figure(3),imshow(uint8(abs((ifft2(A3)))));• • title('Restructuring the image after removing some fourier coefficients');
![Page 15: Image fft](https://reader033.vdocuments.us/reader033/viewer/2022061201/5479895fb4af9f4f328b4607/html5/thumbnails/15.jpg)
Original Image
![Page 16: Image fft](https://reader033.vdocuments.us/reader033/viewer/2022061201/5479895fb4af9f4f328b4607/html5/thumbnails/16.jpg)
![Page 17: Image fft](https://reader033.vdocuments.us/reader033/viewer/2022061201/5479895fb4af9f4f328b4607/html5/thumbnails/17.jpg)
fft fourier transform of horizontal lines
![Page 18: Image fft](https://reader033.vdocuments.us/reader033/viewer/2022061201/5479895fb4af9f4f328b4607/html5/thumbnails/18.jpg)
The peak is at the center for vertical lines and horizontal lines