Slalom changes

perception/tasks/slalom/.gitignore

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+.DS_Store
+.venv/
+GOPR1146 copy.MP4
+outputs/
+train_images
+__pycache__/
+*.pyc
+*.egg-info/
+test_images
+.pytest_cache

perception/tasks/slalom/README.md

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+# slalom
+
+Perception algorithms for RoboSub Task 2: Avoid Debris / Slalom.
+
+The task has three repeated pipe sets arranged as:
+
+```text
+WHITE    RED    WHITE
+```
+
+The AUV should navigate through each set while keeping the red pipe on the same side it used when passing the gate, and while staying vertically within the pipe area.
+
+## Structure
+
+```text
+slalom/
+├── classical/                  # OpenCV detector for red/white vertical PVC pipes (hsv + contrast segmentation)
+├── slalom_sequence_tracker.py  # Multi-gate state across frames: side consistency, distance, and search bias
+├── yolo/                       # Placeholder — no YOLO-based detector exists yet
+└── tests/                      # Synthetic unit tests that exercise the classical detector without pool footage
+```
+
+`classical/` is ported from the original `urb-slalom` prototype sandbox. That sandbox's CLI and video/GoPro test scripts were not carried over here — this package exposes the detector and tracker as a plain Python API instead.
+
+## Usage
+
+```python
+import cv2
+
+from perception.tasks.slalom.classical import PassSide, SlalomDetector
+from perception.tasks.slalom.slalom_sequence_tracker import SlalomSequenceTracker
+
+frame = cv2.imread("path/to/frame.png")
+
+detector = SlalomDetector()
+estimate = detector.detect(frame, pass_side=PassSide.LEFT)
+annotated = detector.annotate(frame, estimate)
+
+# Optional: track gate-passing state across a video's frames
+tracker = SlalomSequenceTracker(focal_length_px=900.0)
+gate_result = tracker.update(estimate, image_width=frame.shape[1])
+```
+
+Use `detector.detect_white_pole_target(...)` / `detector.annotate_white_pole(...)` for proxy footage that has a single white pole instead of a full red/white pipe set. Pass `method="contrast"` to `detect(...)` for footage where water attenuation makes the red pipe read as near-black rather than red-hued (see Known Limitation below).
+
+## Test Data
+
+`Slalom Task/` is a labeled Roboflow dataset (`train/`, `valid/`, `test/`, each with `images/` + YOLO-format `labels/`, plus `data.yaml` with classes `red`/`white`) — useful for testing detection against real course footage rather than just synthetic frames. `crc-photos/` holds additional still frames from pool/tank footage.
+
+## Run Tests
+
+```bash
+pytest perception/tasks/slalom/tests
+```
+
+## Algorithm
+
+1. Convert the frame to HSV.
+2. Segment red pipes with two hue ranges, because red wraps around HSV hue 0.
+3. Segment white pipes using low saturation and high value.
+4. Clean masks with morphological open/close operations.
+5. Extract contours and keep tall, vertical, pipe-like bounding boxes.
+6. Pick the best red pipe and the nearest white pipe on each side.
+7. Compute a target point in the open corridor that keeps the red pipe on the requested side.
+
+The detector returns both raw pipe detections and a `SlalomEstimate`:
+
+- `target_x`: normalized horizontal steering target, where `0.0` is left and `1.0` is right.
+- `target_y`: normalized vertical target, useful for staying within the pipe height.
+- `yaw_error`: normalized horizontal error from image center.
+- `confidence`: simple confidence score based on whether the red pipe and adjacent white pipe were detected.
+
+### Known Limitation: Color Cast
+
+Pixel sampling against both the `Slalom Task` dataset and our own GoPro footage shows that at typical course range, water attenuation shifts the red pipe's hue to nearly match the white pipe's and the background's (within a few degrees of hue) — only brightness (HSV Value) reliably separates them. The current hue-based `DetectorConfig` thresholds do not account for this and should be expected to under-detect on real footage until segmentation is reworked around relative brightness rather than hue.
+
+## ROS 2 Porting Notes
+
+The next step is to wrap `SlalomDetector` in a ROS 2 node that:
+
+- subscribes to `/camera/usb/front/compressed`
+- publishes debug masks/images
+- publishes raw `CVObject` pipe detections
+- publishes one high-level `CVObject` target for task planning
+
+Suggested topics:
+
+```text
+/cv/front/slalom_red_pipe/bounding_box
+/cv/front/slalom_white_left/bounding_box
+/cv/front/slalom_white_right/bounding_box
+/cv/front/slalom_target/bounding_box
+```

perception/tasks/slalom/classical/__init__.py

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+from perception.tasks.slalom.classical.detector import (
+    DetectorConfig,
+    PassSide,
+    PipeDetection,
+    SlalomDetector,
+    SlalomEstimate,
+    WhitePoleEstimate,
+)
+
+__all__ = [
+    "DetectorConfig",
+    "PassSide",
+    "PipeDetection",
+    "SlalomDetector",
+    "SlalomEstimate",
+    "WhitePoleEstimate",
+]