Squire and his team monitor dark web chatrooms around the clock to watch for any clues that could identify and locate abused children
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More top storiesHow forensics uncovered the murder behind bones found at a beauty spot
SSIM (Structural Similarity Index Measure) compares two images by evaluating luminance, contrast, and structural patterns across local windows. It returns a score from -1 to 1: 1.0 means the images are pixel-identical, 0 means no structural correlation, and negative values mean the images are anti-correlated (less alike than random noise). For glyph comparison, it answers the question: do these two rendered characters share the same visual structure?