Add "Vision System"

Vision-System.md

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+# Vision System
+
+## Camera Array — 360° Surround Vision
+
+### 4× IMX219 160° Wide Angle (CSI)
+- **Sensor:** Sony IMX219, 8MP
+- **Resolution:** 3280×2464 (stills), 1080p @ 30fps, 720p @ 60fps (video)
+- **FOV:** 160° wide angle — 4 cameras = full 360° with overlap
+- **Interface:** MIPI CSI-2 (15-pin ribbon cable)
+- **Focus:** Manual focus, 2.96mm lens
+- **Arriving:** March 1, 2026
+
+### Mounting Layout
+```
+            FRONT
+         ┌────────┐
+         │ CAM 0  │  → Forward (0°)
+    ┌────┤  160°  ├────┐
+    │    └────────┘    │
+    │CAM 3          CAM 1│
+    │ Left            Right│
+    │(270°)          (90°) │
+    │    ┌────────┐    │
+    └────┤ CAM 2  ├────┘
+         │  160°  │
+         └────────┘
+            REAR (180°)
+```
+
+Each camera covers 160° — with 4 cameras at 90° intervals, there's ~70° overlap between adjacent cameras. This overlap is useful for:
+- Cross-camera object tracking (hand off between views)
+- Panoramic stitching
+- Stereo depth estimation from adjacent pairs
+
+### RealSense D435i (USB3)
+- **Purpose:** Primary depth sensing + RGB for SLAM/navigation
+- **Mount:** Forward-facing, mid-height on stem
+- **Resolution:** 1280×720 depth @ 30fps + 1080p RGB
+- **Depth range:** 0.2m - 10m
+- **IMU:** Built-in accelerometer + gyroscope
+
+### RPLIDAR A1M8 (USB)
+- **Purpose:** 360° 2D laser scan for SLAM/nav2
+- **Mount:** Top of sensor tower (under helmet)
+- **Range:** 12m, 360°, ~5.5Hz scan rate
+
+## CSI Adapter Required
+The Orin Nano Dev Kit carrier exposes 2 CSI connectors. To use all 4 cameras simultaneously, need a **quad CSI multiplexer**:
+- ArduCam Multi-Camera Adapter for Jetson (~$40 USD)
+- Or Arducam Camarray HAT (hardware sync option)
+- **TODO:** Confirm Orin Nano compatibility before ordering
+
+## Processing Pipeline (on Orin Nano @ 67 TOPS)
+```
+4× IMX219 (CSI) ──→ Jetson ISP (hardware) ──→ TensorRT inference
+                                                ├── Person detection (all 4 streams)
+                                                ├── Object classification
+                                                └── Optical flow / motion
+
+RealSense (USB3) ──→ depth + RGB ──→ SLAM (slam_toolbox)
+                                  ──→ obstacle avoidance (Nav2 costmap)
+
+RPLIDAR (USB) ──→ 2D scan ──→ SLAM (primary scan source)
+```
+
+## Total Sensor Budget
+| Sensor | Interface | Power | Weight |
+|--------|-----------|-------|--------|
+| 4× IMX219 | CSI (0W USB) | ~1W total | ~20g total |
+| RealSense D435i | USB3 | ~1.5W | 72g |
+| RPLIDAR A1 | USB | ~2W | 170g |
+| BME280 | I2C (on FC) | ~0.01W | 2g |
+| **Total** | | **~4.5W** | **~264g** |