Signature Matcher

Quick Start

To get started:

• Provide source signature image via msg.payload.source
• Provide array of signature images to compare via msg.payload.images
• Set the Threshold value (0-1) for match sensitivity
• Receive similarity scores and match results in msg.payload

Configuration

Threshold (required)

Similarity threshold (0-1) for determining if signatures match. Default: 0.35

Note: Lower values are more lenient (more matches), higher values are more strict.

Common Input Format

msg.payload.source (string)

Relative path of the source signature image on shared storage.

Example: "signatures/reference.png"

msg.payload.images (array)

Array of signature image paths to compare against the source.

Example: ["signatures/test1.png", "signatures/test2.png"]

Common Output Format

msg.payload (object)

msg.payload contains an output object with match results. match_score is a 0–100 similarity score.

Example:

{"output": {"matches": [{"image": "test1.png", "match_score": 89.0, "is_match": true}]}}

Example

Input (msg.payload)

{
  "source": "signatures/reference.png",
  "images": ["signatures/test1.png", "signatures/test2.png"]
}

Output (msg.payload)

{
  "output": {
    "matches": [
      { "image": "test1.png", "match_score": 89.0, "is_match": true },
      { "image": "test2.png", "match_score": 25.0, "is_match": false }
    ]
  }
}

Errors

When the block fails, it raises an error. Use a Catch block in your flow to handle failures and inspect the error payload.

Common mistakes

• Invalid image path: Source or comparison image paths are incorrect or files don't exist on shared storage.
• Unsupported format: Image format is not supported. Use standard image formats (.png, .jpg, .jpeg).
• Invalid threshold: Threshold must be between 0 and 1.
• Empty images array: No comparison images provided in msg.payload.images.
• Service unavailable: The service is unavailable or unreachable.

Best Practices

• Use clear, high-resolution signature images for better comparison accuracy
• Ensure signatures are properly cropped with minimal background noise
• Start with threshold 0.35 and adjust based on your security requirements
• Lower threshold (0.2-0.3) for more lenient matching, higher (0.4-0.5) for stricter verification
• Test with known matching and non-matching pairs to calibrate threshold
• Ensure consistent image quality and resolution across all signatures being compared
• Always validate results in production authentication systems
• Consider using multiple verification methods for critical authentication scenarios