Open-source project reverse-engineers detection and removal of Gemini's SynthID watermark

Without access to Google's SynthID encoder/decoder, it recovers the structure of the invisible watermark in Gemini images using only pure signal processing and spectral analysis.

The key insight is that a carrier is inserted at different frequency locations depending on resolution, and a phase template remains consistent across images generated by the same model.

Based on this, the project presents methods to trace back the watermark's structure in order to detect or remove it.

• Target: SynthID watermark in Gemini-generated images
• Method: signal-processing-based analysis without encoder/decoder
• Findings: resolution-specific frequency carrier placement and repeatability of the phase template
• Significance: an empirical case of reverse-engineering how an invisible watermark works