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Python: improve image compare program #16601

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Merged
mcgratta merged 1 commit into from
Sep 27, 2026
+22 −18
Merged

Python: improve image compare program #16601

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40 changes: 22 additions & 18 deletions Utilities/Python/scripts/make_smv_images.py
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Original file line number Diff line number Diff line change
Expand Up @@ -14,26 +14,30 @@
from PIL import Image
import numpy as np

def compare_images(image1_path, image2_path):

img1 = Image.open(image1_path).convert('RGB')
img2 = Image.open(image2_path).convert('RGB')
def compare_images(image1_path, image2_path, threshold=10):
img1 = Image.open(image1_path).convert("RGB")
img2 = Image.open(image2_path).convert("RGB")

if img1.size != img2.size:
print(f"Warning: Images have different sizes. Resizing {image2_path} to match {image1_path}")
img2 = img2.resize(img1.size, Image.LANCZOS)
raise ValueError("Images must have the same dimensions")

arr1 = np.array(img1, dtype=np.float64)
arr2 = np.array(img2, dtype=np.float64)
arr1 = np.array(img1, dtype=np.int16)
arr2 = np.array(img2, dtype=np.int16)

# Calculate Mean Squared Error (MSE)
mse = np.mean((arr1 - arr2) ** 2)
diff = np.abs(arr1 - arr2)
pixel_diff = np.max(diff, axis=2)

changed_pixels = np.sum(pixel_diff > threshold)
total_pixels = pixel_diff.size

# Calculate normalized similarity percentage (0-100%)
max_mse = 255.0 ** 2
similarity_percentage = (1 - (mse / max_mse)) * 100
difference_percentage = (changed_pixels / total_pixels) * 100

mse = np.mean((arr1 - arr2) ** 2)

return { 'mse': mse, 'similarity_percentage': similarity_percentage }
return {
"mse": mse,
"difference_percentage": difference_percentage
}


parser = argparse.ArgumentParser(description="A script to generate Smokeview images")
Expand Down Expand Up @@ -72,9 +76,9 @@ def compare_images(image1_path, image2_path):
try:
if os_name == "Linux":
subprocess.run(['xvfb-run','-w','2','-s','-fp /usr/share/X11/fonts/misc -screen 0 1280x1024x24','-a',smokeview_path,
'-bindir',bindir,'-runscript', case[i] ], check=True, stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
'-bindir',bindir,'-runscript', '-render_overwrite', case[i] ], check=True, stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
else:
subprocess.run([smokeview_path,'-bindir',bindir,'-runscript',case[i]],
subprocess.run([smokeview_path,'-bindir',bindir,'-runscript','-render_overwrite', case[i]],
check=True, stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
except subprocess.CalledProcessError as e:
print(f"Error: Smokeview failed with return code {e.returncode}")
Expand All @@ -100,8 +104,8 @@ def compare_images(image1_path, image2_path):

try:
results = compare_images(directory+png_file.name, refdir+png_file.name)
if results['similarity_percentage'] < 98:
print('Warning: ',png_file.name,f"{results['similarity_percentage']:.2f}%")
if results['difference_percentage'] > 1:
print('Warning: ',png_file.name,' changed ',f"{results['difference_percentage']:.2f}%")
except FileNotFoundError as e:
print(f"Error: Could not find image file - {e}")
sys.exit(1)
Expand Down