diff --git a/.gitignore b/.gitignore
index 95a6253..153385f 100644
--- a/.gitignore
+++ b/.gitignore
@@ -207,6 +207,7 @@ __marimo__/
 
 # Projects
 datasets/
+!mini-nav/**/datasets/
 data/
 deps/
 outputs/
diff --git a/mini-nav/configs/__init__.py b/mini-nav/configs/__init__.py
index f62aed0..68771ba 100644
--- a/mini-nav/configs/__init__.py
+++ b/mini-nav/configs/__init__.py
@@ -5,6 +5,7 @@ from .config import (
 from .loader import ConfigError, load_yaml, save_yaml
 from .models import (
     Config,
+    DatasetConfig,
     ModelConfig,
     OutputConfig,
     PoolingType,
@@ -14,6 +15,7 @@ __all__ = [
     # Models
     "ModelConfig",
     "OutputConfig",
+    "DatasetConfig",
     "Config",
     "PoolingType",
     # Loader
diff --git a/mini-nav/configs/config.yaml b/mini-nav/configs/config.yaml
index 8c1f7f6..9c05347 100644
--- a/mini-nav/configs/config.yaml
+++ b/mini-nav/configs/config.yaml
@@ -5,3 +5,13 @@ model:
 
 output:
   directory: "./outputs"
+
+dataset:
+  dataset_root: "datasets/InsDet-FULL"
+  output_dir: "datasets/InsDet-FULL/Synthesized"
+  num_objects_range: [3, 8]
+  num_scenes: 1000
+  object_scale_range: [0.1, 0.4]
+  rotation_range: [-30, 30]
+  overlap_threshold: 0.3
+  seed: 42
diff --git a/mini-nav/configs/models.py b/mini-nav/configs/models.py
index 16a443c..dd6c9cd 100644
--- a/mini-nav/configs/models.py
+++ b/mini-nav/configs/models.py
@@ -1,17 +1,10 @@
 """Pydantic data models for feature compressor configuration."""
 
-from enum import Enum
 from pathlib import Path
 
 from pydantic import BaseModel, ConfigDict, Field, field_validator
 
 
-class PoolingType(str, Enum):
-    """Enum for pooling types."""
-
-    ATTENTION = "attention"
-
-
 class ModelConfig(BaseModel):
     """Configuration for the vision model and compression."""
 
@@ -42,10 +35,60 @@ class OutputConfig(BaseModel):
         return Path(__file__).parent.parent.parent / v
 
 
+class DatasetConfig(BaseModel):
+    """Configuration for synthetic dataset generation."""
+
+    model_config = ConfigDict(extra="ignore")
+
+    dataset_root: Path = (
+        Path(__file__).parent.parent.parent / "datasets" / "InsDet-FULL"
+    )
+    output_dir: Path = (
+        Path(__file__).parent.parent.parent / "datasets" / "InsDet-FULL" / "Synthesized"
+    )
+    num_objects_range: tuple[int, int] = (3, 8)
+    num_scenes: int = 1000
+    object_scale_range: tuple[float, float] = (0.1, 0.4)
+    rotation_range: tuple[int, int] = (-30, 30)
+    overlap_threshold: float = 0.3
+    seed: int = 42
+
+    @field_validator("dataset_root", "output_dir", mode="after")
+    def convert_to_absolute(cls, v: Path) -> Path:
+        """
+        Converts the path to an absolute path relative to the project root.
+        This works even if the path doesn't exist on disk.
+        """
+        if v.is_absolute():
+            return v
+        return Path(__file__).parent.parent.parent / v
+
+    @field_validator("num_objects_range", mode="after")
+    def validate_num_objects(cls, v: tuple[int, int]) -> tuple[int, int]:
+        if v[0] < 1 or v[1] < v[0]:
+            raise ValueError("num_objects_range must have min >= 1 and min <= max")
+        return v
+
+    @field_validator("object_scale_range", mode="after")
+    def validate_scale(cls, v: tuple[float, float]) -> tuple[float, float]:
+        if v[0] <= 0 or v[1] <= 0 or v[1] < v[0]:
+            raise ValueError(
+                "object_scale_range must have positive values and min <= max"
+            )
+        return v
+
+    @field_validator("overlap_threshold", mode="after")
+    def validate_overlap(cls, v: float) -> float:
+        if not 0 <= v <= 1:
+            raise ValueError("overlap_threshold must be between 0 and 1")
+        return v
+
+
 class Config(BaseModel):
     """Root configuration for the feature compressor."""
 
     model_config = ConfigDict(extra="ignore")
 
-    model: ModelConfig
-    output: OutputConfig
+    model: ModelConfig = Field(default_factory=ModelConfig)
+    output: OutputConfig = Field(default_factory=OutputConfig)
+    dataset: DatasetConfig = Field(default_factory=DatasetConfig)
diff --git a/mini-nav/datasets/__init__.py b/mini-nav/datasets/__init__.py
new file mode 100644
index 0000000..4eb1ddc
--- /dev/null
+++ b/mini-nav/datasets/__init__.py
@@ -0,0 +1,8 @@
+from .loader import SynthDataset, ValDataset
+from .synthesizer import ImageSynthesizer
+
+__all__ = [
+    "ImageSynthesizer",
+    "SynthDataset",
+    "ValDataset",
+]
diff --git a/mini-nav/datasets/loader.py b/mini-nav/datasets/loader.py
new file mode 100644
index 0000000..d0f79e3
--- /dev/null
+++ b/mini-nav/datasets/loader.py
@@ -0,0 +1,105 @@
+"""Data loaders for synthetic and validation datasets."""
+
+from collections.abc import Iterator
+from pathlib import Path
+
+from PIL import Image
+
+
+class SynthDataset:
+    """Dataset loader for synthesized training images."""
+
+    def __init__(self, synth_dir: Path, annotations_suffix: str = ".txt"):
+        """
+        Initialize the synthetic dataset loader.
+
+        Args:
+            synth_dir: Directory containing synthesized images and annotations
+            annotations_suffix: Suffix for annotation files
+        """
+        self.synth_dir = Path(synth_dir)
+        self.annotations_suffix = annotations_suffix
+
+        # Find all images
+        self.image_files = sorted(self.synth_dir.glob("synth_*.jpg"))
+
+    def __len__(self) -> int:
+        return len(self.image_files)
+
+    def __getitem__(self, idx: int) -> tuple[Image.Image, list[tuple[str, int, int, int, int]]]:
+        """Get a single item.
+
+        Args:
+            idx: Index of the item
+
+        Returns:
+            Tuple of (image, annotations) where annotations is a list of
+            (category, xmin, ymin, xmax, ymax)
+        """
+        img_path = self.image_files[idx]
+        image = Image.open(img_path).convert("RGB")
+
+        # Load annotations
+        anno_path = img_path.with_suffix(self.annotations_suffix)
+        annotations: list[tuple[str, int, int, int, int]] = []
+
+        if anno_path.exists():
+            with open(anno_path, "r") as f:
+                for line in f:
+                    line = line.strip()
+                    if line:
+                        parts = line.split()
+                        if len(parts) == 5:
+                            category = parts[0]
+                            xmin, ymin, xmax, ymax = map(int, parts[1:])
+                            annotations.append((category, xmin, ymin, xmax, ymax))
+
+        return image, annotations
+
+    def __iter__(self) -> Iterator[tuple[Image.Image, list[tuple[str, int, int, int, int]]]]:
+        """Iterate over the dataset."""
+        for i in range(len(self)):
+            yield self[i]
+
+
+class ValDataset:
+    """Dataset loader for validation scene images."""
+
+    def __init__(self, scenes_dir: Path, split: str = "easy"):
+        """
+        Initialize the validation dataset loader.
+
+        Args:
+            scenes_dir: Directory containing scene subdirectories
+            split: Scene split to load ('easy' or 'hard')
+        """
+        self.scenes_dir = Path(scenes_dir)
+        self.split = split
+
+        self.split_dir = self.scenes_dir / split
+        if not self.split_dir.exists():
+            raise ValueError(f"Scene split directory not found: {self.split_dir}")
+
+        # Find all RGB images
+        self.image_files = sorted(self.split_dir.glob("*/rgb_*.jpg"))
+
+    def __len__(self) -> int:
+        return len(self.image_files)
+
+    def __getitem__(self, idx: int) -> tuple[Image.Image, Path]:
+        """Get a single item.
+
+        Args:
+            idx: Index of the item
+
+        Returns:
+            Tuple of (image, scene_path)
+        """
+        img_path = self.image_files[idx]
+        image = Image.open(img_path).convert("RGB")
+        return image, img_path.parent
+
+    def __iter__(self) -> Iterator[tuple[Image.Image, Path]]:
+        """Iterate over the dataset."""
+        for i in range(len(self)):
+            yield self[i]
diff --git a/mini-nav/datasets/synthesizer.py b/mini-nav/datasets/synthesizer.py
new file mode 100644
index 0000000..553b466
--- /dev/null
+++ b/mini-nav/datasets/synthesizer.py
@@ -0,0 +1,295 @@
+"""Image synthesizer for generating synthetic object detection datasets."""
+
+import random
+from pathlib import Path
+
+import numpy as np
+from PIL import Image
+from PIL.Image import Resampling
+
+
+class ImageSynthesizer:
+    """Synthesizes composite images from background and object images with masks."""
+
+    def __init__(
+        self,
+        dataset_root: Path,
+        output_dir: Path,
+        num_objects_range: tuple[int, int] = (3, 8),
+        num_scenes: int = 1000,
+        object_scale_range: tuple[float, float] = (0.1, 0.4),
+        rotation_range: tuple[int, int] = (-30, 30),
+        overlap_threshold: float = 0.3,
+        seed: int = 42,
+    ):
+        """
+        Initialize the image synthesizer.
+
+        Args:
+            dataset_root: Root directory of the dataset (InsDet-FULL)
+            output_dir: Directory to save synthesized images
+            num_objects_range: Range of number of objects per scene
+            num_scenes: Number of scenes to generate
+            object_scale_range: Range of object scale relative to background
+            rotation_range: Range of rotation angles in degrees
+            overlap_threshold: Maximum allowed overlap ratio
+            seed: Random seed for reproducibility
+        """
+        self.dataset_root = Path(dataset_root)
+        self.output_dir = Path(output_dir)
+        self.num_objects_range = num_objects_range
+        self.num_scenes = num_scenes
+        self.object_scale_range = object_scale_range
+        self.rotation_range = rotation_range
+        self.overlap_threshold = overlap_threshold
+        self.seed = seed
+
+        self.background_dir = self.dataset_root / "Background"
+        self.objects_dir = self.dataset_root / "Objects"
+        self.scenes_dir = self.dataset_root / "Scenes"
+
+        # Will be populated on first use
+        self._background_categories: list[str] | None = None
+        self._object_categories: list[str] | None = None
+
+    @property
+    def background_images(self) -> list[Path]:
+        """List of background image paths."""
+        if self._background_categories is None:
+            self._background_categories = sorted(
+                [p.name for p in self.background_dir.iterdir() if p.suffix in [".jpg", ".jpeg", ".png"]]
+            )
+        # Return as list of Path for type compatibility
+        return [self.background_dir / name for name in self._background_categories]  # type: ignore[return-value]
+
+    @property
+    def object_categories(self) -> list[str]:
+        """List of object categories."""
+        if self._object_categories is None:
+            self._object_categories = sorted(
+                [d.name for d in self.objects_dir.iterdir() if d.is_dir()]
+            )
+        return self._object_categories
+
+    def load_background(self, path: Path) -> Image.Image:
+        """Load a background image.
+
+        Args:
+            path: Background image path
+
+        Returns:
+            PIL Image
+        """
+        return Image.open(path).convert("RGB")
+
+    def load_object(self, category: str, angle: int) -> tuple[Image.Image, Image.Image]:
+        """Load an object image and its mask.
+
+        Args:
+            category: Object category name (e.g., '099_mug_blue')
+            angle: Angle index (1-24)
+
+        Returns:
+            Tuple of (image, mask) as PIL Images
+        """
+        img_path = self.objects_dir / category / "images" / f"{angle:03d}.jpg"
+        mask_path = self.objects_dir / category / "masks" / f"{angle:03d}.png"
+        image = Image.open(img_path).convert("RGB")
+        mask = Image.open(mask_path).convert("L")
+        return image, mask
+
+    def get_random_background(self) -> tuple[Image.Image, Path]:
+        """Get a random background image.
+
+        Returns:
+            Tuple of (image, path)
+        """
+        path = random.choice(self.background_images)
+        return self.load_background(path), path
+
+    def get_random_object(self) -> tuple[Image.Image, Image.Image, str]:
+        """Get a random object with its mask.
+
+        Returns:
+            Tuple of (image, mask, category_name)
+        """
+        category = random.choice(self.object_categories)
+        angle = random.randint(1, 24)
+        image, mask = self.load_object(category, angle)
+        return image, mask, category
+
+    def _rotate_image_and_mask(
+        self, image: Image.Image, mask: Image.Image, angle: float
+    ) -> tuple[Image.Image, Image.Image]:
+        """Rotate image and mask together."""
+        image = image.rotate(angle, resample=Resampling.BILINEAR, expand=True)
+        mask = mask.rotate(angle, resample=Resampling.BILINEAR, expand=True)
+        return image, mask
+
+    def _compute_overlap(self, box1: tuple[int, int, int, int], box2: tuple[int, int, int, int]) -> float:
+        """Compute overlap ratio between two boxes.
+
+        Args:
+            box1: (xmin, ymin, xmax, ymax)
+            box2: (xmin, ymin, xmax, ymax)
+
+        Returns:
+            Overlap ratio (area of intersection / area of smaller box)
+        """
+        x1_min, y1_min, x1_max, y1_max = box1
+        x2_min, y2_min, x2_max, y2_max = box2
+
+        # Compute intersection
+        inter_xmin = max(x1_min, x2_min)
+        inter_ymin = max(y1_min, y2_min)
+        inter_xmax = min(x1_max, x2_max)
+        inter_ymax = min(y1_max, y2_max)
+
+        if inter_xmax <= inter_xmin or inter_ymax <= inter_ymin:
+            return 0.0
+
+        inter_area = (inter_xmax - inter_xmin) * (inter_ymax - inter_ymin)
+        box1_area = (x1_max - x1_min) * (y1_max - y1_min)
+        box2_area = (x2_max - x2_min) * (y2_max - y2_min)
+        min_area = min(box1_area, box2_area)
+
+        return inter_area / min_area if min_area > 0 else 0.0
+
+    def _place_object(
+        self,
+        background: Image.Image,
+        obj_image: Image.Image,
+        obj_mask: Image.Image,
+        existing_boxes: list[tuple[int, int, int, int]],
+        scale: float,
+    ) -> tuple[Image.Image, Image.Image, tuple[int, int, int, int]] | None:
+        """Place an object on the background without exceeding overlap threshold.
+
+        Args:
+            background: Background PIL Image
+            obj_image: Object PIL Image (RGB)
+            obj_mask: Object PIL Image (L)
+            existing_boxes: List of existing object boxes
+            scale: Scale factor for the object
+
+        Returns:
+            Tuple of (new_background, updated_mask, new_box) or None if placement failed
+        """
+        bg_w, bg_h = background.size
+
+        # Scale object
+        obj_w, obj_h = obj_image.size
+        new_w = int(obj_w * scale)
+        new_h = int(obj_h * scale)
+
+        if new_w <= 0 or new_h <= 0:
+            return None
+
+        obj_image = obj_image.resize((new_w, new_h), Resampling.LANCZOS)
+        obj_mask = obj_mask.resize((new_w, new_h), Resampling.LANCZOS)
+
+        # Try to find a valid position
+        max_attempts = 50
+        for _ in range(max_attempts):
+            # Random position
+            x = random.randint(0, bg_w - new_w)
+            y = random.randint(0, bg_h - new_h)
+
+            new_box = (x, y, x + new_w, y + new_h)
+
+            # Check overlap with existing boxes
+            valid = True
+            for existing_box in existing_boxes:
+                overlap = self._compute_overlap(new_box, existing_box)
+                if overlap > self.overlap_threshold:
+                    valid = False
+                    break
+
+            if valid:
+                # Composite object onto background
+                background = background.copy()
+                mask_array = np.array(obj_mask) / 255.0
+                bg_array = np.array(background)
+                obj_array = np.array(obj_image)
+
+                # Apply mask
+                mask_3d = np.stack([mask_array] * 3, axis=-1)
+                bg_array[y:y+new_h, x:x+new_w] = (
+                    bg_array[y:y+new_h, x:x+new_w] * (1 - mask_3d) +
+                    obj_array * mask_3d
+                )
+
+                return Image.fromarray(bg_array), obj_mask, new_box
+
+        return None
+
+    def synthesize_scene(self) -> tuple[Image.Image, list[tuple[str, int, int, int, int]]]:
+        """Synthesize a single scene with random objects.
+
+        Returns:
+            Tuple of (synthesized_image, list of (category, xmin, ymin, xmax, ymax))
+        """
+        random.seed(self.seed)
+        np.random.seed(self.seed)
+
+        # Load background
+        background, _ = self.get_random_background()
+
+        # Determine number of objects
+        num_objects = random.randint(*self.num_objects_range)
+
+        # Place objects
+        placed_boxes: list[tuple[int, int, int, int]] = []
+        annotations: list[tuple[str, int, int, int, int]] = []
+
+        for _ in range(num_objects):
+            # Get random object
+            obj_image, obj_mask, obj_category = self.get_random_object()
+
+            # Get random scale
+            scale = random.uniform(*self.object_scale_range)
+
+            # Get random rotation
+            angle = random.uniform(*self.rotation_range)
+            obj_image, obj_mask = self._rotate_image_and_mask(obj_image, obj_mask, angle)
+
+            # Try to place object
+            result = self._place_object(background, obj_image, obj_mask, placed_boxes, scale)
+
+            if result is not None:
+                background, _, box = result
+                placed_boxes.append(box)
+                annotations.append((obj_category, box[0], box[1], box[2], box[3]))
+
+        return background, annotations
+
+    def generate(self) -> list[Path]:
+        """Generate all synthesized scenes.
+
+        Returns:
+            List of paths to generated images
+        """
+        self.output_dir.mkdir(parents=True, exist_ok=True)
+
+        generated_files: list[Path] = []
+
+        for i in range(self.num_scenes):
+            # Update seed for each scene
+            random.seed(self.seed + i)
+            np.random.seed(self.seed + i)
+
+            image, annotations = self.synthesize_scene()
+
+            # Save image
+            img_path = self.output_dir / f"synth_{i:04d}.jpg"
+            image.save(img_path, quality=95)
+
+            # Save annotation
+            anno_path = self.output_dir / f"synth_{i:04d}.txt"
+            with open(anno_path, "w") as f:
+                for category, xmin, ymin, xmax, ymax in annotations:
+                    f.write(f"{category} {xmin} {ymin} {xmax} {ymax}\n")
+
+            generated_files.append(img_path)
+
+        return generated_files