Add overview and reorg

Author: crandmck

docs/trustmark-oveview.md

@@ -0,0 +1,31 @@
+---
+id: trustmark-overview
+title: TrustMark watermarking
+---
+
+TrustMark is an open-source universal watermarking system for images that:  
+- Can encode, decode, and remove watermarks from images.
+- Works with arbitrary resolution images.
+- Has implementations in both Python (using PyTorch) and JavaScript (using ONNX).
+
+## Variants
+
+TrustMark has three primary model variants, each with different characteristics.
+
+Images encoded with one variant cannot be decoded with another variant, so you need to stick with the same variant throughout your pipeline.
+
+- **Variant Q (Default)** Use in most cases, where you want a good balance between robustness and imperceptibility.  PSNR is 48-50 dB.
+- **Variant P** - Use when image quality is the top priority. PSNR is 43-45 dB.
+- **Variant C (Compact)** - Use if you need to minimize model size and can live with slightly lower visual quality. PSNR is 38-39 dB.
+
+The general recommendation is to use either:
+- Variant Q for most use cases
+- Variant P when visual quality is paramount
+
+### About PSNR
+
+PSNR (Peak Signal-to-Noise Ratio) is a technical metric used to measure image quality, particularly when comparing an original image to a modified version (in this case, the watermarked image). PSNR is measured in decibels (dB), and higher values indicate better image quality:
+- Values around 40+ dB typically indicate very good quality
+- Values around 30 dB indicate acceptable quality
+- Values below 20 dB usually indicate poor quality
+

sidebars.js

@@ -271,14 +271,14 @@ const sidebars = {
         },
         {
           type: 'category',
-          label: 'TrustMark',
-          link: { type: 'doc', id: 'trustmark/readme' },
+          label: 'TrustMark watermarking',
+          link: { type: 'doc', id: 'trustmark-overview' },
           collapsed: true,
           items: [
             {
               type: 'doc',
-              id: 'trustmark/faq',
-              label: 'FAQ',
+              id: 'trustmark/readme',
+              label: 'Overview',
             },
             {
               type: 'doc',
@@ -287,13 +287,13 @@ const sidebars = {
             },
             {
               type: 'doc',
-              id: 'trustmark/js-readme',
-              label: 'TrustMark JS',
+              id: 'trustmark/faq',
+              label: 'FAQ',
             },
             {
               type: 'doc',
-              id: 'trustmark/python-readme',
-              label: 'FAQ',
+              id: 'trustmark/js-readme',
+              label: 'JavaScript implementation',
             },
           ],
         },