import numpy as np
from scipy import fftpack
from PIL import Image
import os
def load_and_prepare_image(file_path):
img = Image.open(file_path).convert('L')
return np.array(img)
def compute_fft(image):
f = np.fft.fft2(image)
fshift = np.fft.fftshift(f)
magnitude_spectrum = 20*np.log(np.abs(fshift) + 1e-10)
return magnitude_spectrum
def radial_profile(data, center):
y, x = np.indices(data.shape)
r = np.sqrt((x - center[0])**2 + (y - center[1])**2)
r = r.astype(int)
tbin = np.bincount(r.ravel(), data.ravel())
nr = np.bincount(r.ravel())
radialprofile = np.divide(tbin, nr, where=nr!=0)
return radialprofile
def compute_spectral_slope(fft_image):
center = tuple(map(lambda x: x // 2, fft_image.shape))
radial_prof = radial_profile(fft_image, center)
frequencies = np.fft.fftfreq(len(radial_prof))[1:len(radial_prof)//2]
power = radial_prof[1:len(radial_prof)//2]
mask = np.isfinite(power) & (power > 0)
frequencies, power = frequencies[mask], power[mask]
log_freq = np.log(frequencies)
log_power = np.log(power)
slope, _ = np.polyfit(log_freq, log_power, 1)
return slope
def process_image(file_path):
image = load_and_prepare_image(file_path)
fft_image = compute_fft(image)
slope = compute_spectral_slope(fft_image)
# Save FFT image
fft_filename = os.path.splitext(file_path)[0] + "_fft.png"
Image.fromarray(fft_image.astype(np.uint8)).save(fft_filename)
return fft_filename, slope
def generate_html(results):
html_content = """
| Original Image |
2D FFT |
Spectral Slope |
"""
for original_path, fft_path, slope in results:
html_content += f"""
 |
 |
{slope:.4f} |
"""
html_content += """
"""
with open("powerSpectra.html", "w") as f:
f.write(html_content)
# List of image file paths
image_files = [
'1722307680.png',
'1722307715.png',
'1722307729.png',
'1722307742.png',
'forest.jpg',
'streetviewKingStreet.jpeg',
'streetviewNorfolkStreet.jpeg'
]
# Process each image
results = []
for file_path in image_files:
fft_path, slope = process_image(file_path)
results.append((file_path, fft_path, slope))
print(f"Processed {file_path}, spectral slope: {slope:.4f}")
# Generate HTML
generate_html(results)
print("powerSpectra.html has been generated.")