Add fft.py

datasets/raise/fft/fft.py

@@ -0,0 +1,36 @@
+from scipy import fftpack
+import numpy as np
+import imageio
+from PIL import Image, ImageDraw
+
+image1 = imageio.imread('image.jpg',as_gray=True)
+
+#convert image to numpy array
+image1_np=np.array(image1)
+
+#fft of image
+fft1 = fftpack.fftshift(fftpack.fft2(image1_np))
+
+#Create a low pass filter image
+x,y = image1_np.shape[0],image1_np.shape[1]
+#size of circle
+e_x,e_y=50,50
+#create a box
+bbox=((x/2)-(e_x/2),(y/2)-(e_y/2),(x/2)+(e_x/2),(y/2)+(e_y/2))
+
+low_pass=Image.new("L",(image1_np.shape[0],image1_np.shape[1]),color=0)
+
+draw1=ImageDraw.Draw(low_pass)
+draw1.ellipse(bbox, fill=1)
+
+low_pass_np=np.array(low_pass)
+
+#multiply both the images
+filtered=np.multiply(fft1,low_pass_np)
+
+#inverse fft
+ifft2 = np.real(fftpack.ifft2(fftpack.ifftshift(filtered)))
+ifft2 = np.maximum(0, np.minimum(ifft2, 255))
+
+#save the image
+imageio.imsave('fft-then-ifft.png', ifft2.astype(np .uint8))