training/segmentation_train.py

import os
from ultralytics import YOLO

project = f"{os.getcwd()}/runs"
device = "cuda:2"
imgsz = 640
epochs = 20

# Stage 1: Pretrain on SeaTurtleID2022 (large dataset)
model = YOLO("yolo11s-seg.pt")
model.train(
    data="segmentation_stage1.yaml",
    project=project,
    name="stage1",
    epochs=epochs,
    imgsz=imgsz,
    device=device,
    fliplr=0,
    flipud=0,
)

# Stage 2: Fine-tune on combined dataset (balanced)
model = YOLO(f"{project}/stage1/weights/last.pt")
model.train(
    data="segmentation_stage2.yaml",
    project=project,
    name="stage2",
    epochs=epochs,
    imgsz=imgsz,
    device=device,
    fliplr=0,
    flipud=0,

    freeze=5,
)