Python: Add image comparison tool

Author: mcgratta

Utilities/Python/scripts/make_smv_images.py

@@ -2,13 +2,39 @@
 # Make Smokeview images for the FDS Manuals.
 # The script gets the smokeview executable appropriate for your OS from the smv repository 
 # unless you provide an optional full path to the executable as an argument.
+# After images are created, a comparison is made with the reference figures in the fig repository.
 
 import pandas as pd
 import os
 import subprocess
 import shutil
 import platform
 import argparse
+import sys
+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')
+
+    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)
+
+    arr1 = np.array(img1, dtype=np.float64)
+    arr2 = np.array(img2, dtype=np.float64)
+
+    # Calculate Mean Squared Error (MSE)
+    mse = np.mean((arr1 - arr2) ** 2)
+
+    # Calculate normalized similarity percentage (0-100%)
+    max_mse = 255.0 ** 2
+    similarity_percentage = (1 - (mse / max_mse)) * 100
+
+    return { 'mse': mse, 'similarity_percentage': similarity_percentage }
+
 
 parser = argparse.ArgumentParser(description="A script to generate Smokeview images")
 parser.add_argument("message", nargs="?", default="null", help="Optional smokeview path")
@@ -57,3 +83,29 @@
 
     os.chdir(original_dir)
 
+# Compare images just created against the reference images in the fig repository
+
+from pathlib import Path
+
+mandir = '../../Manuals/'
+refdir = '../../../fig/fds/Reference_Figures/'
+directories = [mandir+'FDS_User_Guide/SCRIPT_FIGURES/' , mandir+'FDS_Verification_Guide/SCRIPT_FIGURES/']
+
+print('comparing images with reference figures...')
+
+for directory in directories:
+    dir_path = Path(directory)
+    
+    for png_file in dir_path.glob("*.png"):
+
+        try:
+            results = compare_images(directory+png_file.name, refdir+png_file.name)
+            if results['similarity_percentage'] < 90:
+                print('Warning: ',png_file.name,f"{results['similarity_percentage']:.2f}%")
+        except FileNotFoundError as e:
+            print(f"Error: Could not find image file - {e}")
+            sys.exit(1)
+        except Exception as e:
+            print(f"Error: {e}")
+            sys.exit(1)
+