Invite contributors for image generation to improve detection

Added a section inviting contributors to help expand the codebook by generating pure black and white images using Nano Banana Pro.

README.md

@@ -26,6 +26,35 @@ This project reverse-engineers **Google's SynthID** watermarking system - the in
 2. **Built a detector** that identifies SynthID watermarks with 90% accuracy
 3. **Developed a multi-resolution spectral bypass** (V3) that achieves **75% carrier energy drop**, **91% phase coherence drop**, and **43+ dB PSNR** on any image resolution
 
+---
+
+## 🚨 Contributors Wanted: Help Expand the Codebook
+
+We're actively collecting **pure black and pure white images generated by Nano Banana Pro** to improve multi-resolution watermark extraction.
+
+If you can generate these:
+
+- Resolution: any (higher variety = better)
+- Content: **fully black (#000000)** or **fully white (#FFFFFF)**
+- Source: Nano Banana Pro outputs only
+
+### How to Contribute
+
+1. Generate a batch of black/white images by attaching a pure black/white image into Gemini and prompting it to "recreate this as it is"
+2. Place them in new folders:
+   - `gemini_black_nb_pro/` (for black)
+   - `gemini_white_nb_pro/` (for white)
+3. Open a Pull Request 🚀
+
+These reference images are **critical** for:
+- Carrier frequency discovery
+- Phase validation
+- Improving cross-resolution robustness
+
+> Even 150–200 images at a new resolution can significantly improve detection and removal.
+
+---
+
 ### What Makes This Different
 
 Unlike brute-force approaches (JPEG compression, noise injection), our V3 bypass uses a **multi-resolution SpectralCodebook** - a collection of per-resolution watermark fingerprints stored in a single file. At bypass time, the codebook auto-selects the matching resolution profile, enabling surgical frequency-bin-level removal on any image size.