docs/en/datasets/depth/index.md
Monocular depth estimation assigns a depth value in meters to every pixel in an image. Depth targets use either scaled 16-bit grayscale PNGs or floating-point NPY arrays in meters.
This guide explains the dataset format used by Ultralytics YOLO depth estimation models and lists the built-in dataset configurations available for training and validation.
Each training sample consists of one RGB image and one paired depth file. PNG values are divided by the optional dataset-level depth_scale to produce meters. The default is 1000, so a value of 1500 represents 1.5 meters. Code 0 means invalid; PNGs need no embedded metadata.
.png (preferred) or .npy. PNG maps must be 2D uint16 grayscale images. NPY arrays must be 2D and floating-point, with values in meters.depth_scale only when PNGs do not use the default millimeter convention. For example, KITTI uses 256 and Virtual KITTI 2 uses 100.scene_001.png pairs with scene_001.jpg).images directory component with depth, preferring .png and falling back to .npy.≤ 0 are treated as invalid and excluded from loss and metric computation.Because code 0 is reserved for invalid pixels, a uint16 PNG provides 65,535 positive depth values. The scale controls both precision and range:
| Convention | depth_scale | Resolution | Maximum depth |
|---|---|---|---|
| Default / ARKitScenes | 1000 | 1 mm | 65.535 m |
| KITTI | 256 | 3.90625 mm | 255.99609375 m |
| Virtual KITTI 2 | 100 | 1 cm | 655.35 m |
These are storage limits, not recommended training caps. A dataset can set a smaller max_depth independently for loss calibration or evaluation.
The standard layout keeps images and depth maps in parallel folders:
dataset/
├── images/
│ ├── train/
│ └── val/
└── depth/
├── train/
└── val/
For example, an image at images/train/scene_001.jpg is paired with a depth map at depth/train/scene_001.png.
Depth estimation datasets are configured with YAML files. The main fields are:
| Key | Description |
|---|---|
path | Dataset root directory. |
train | Training image path relative to path, or an absolute path. |
val | Validation image path relative to path, or an absolute path. |
test | Optional test image path. |
nc | Number of classes — always 1 for depth estimation. |
names | Class name mapping — always {0: depth}. |
depth_scale | Optional PNG units per meter; defaults to 1000. |
!!! example "ultralytics/cfg/datasets/nyu-depth.yaml"
```yaml
--8<-- "ultralytics/cfg/datasets/nyu-depth.yaml"
```
Train a YOLO26 depth estimation model with Python or CLI:
!!! example
=== "Python"
```python
from ultralytics import YOLO
# Load a pretrained depth model
model = YOLO("yolo26n-depth.pt")
# Train on the NYU Depth V2 dataset
results = model.train(data="nyu-depth.yaml", epochs=100, imgsz=640)
```
=== "CLI"
```bash
yolo depth train data=nyu-depth.yaml model=yolo26n-depth.pt epochs=100 imgsz=640
```
The YOLO26 depth models are pretrained on a broad multi-dataset mix (~2.19M images) spanning indoor (≤10 m) to outdoor (~80 m) ranges, then evaluated zero-shot across five benchmarks. Each dataset has a dedicated page:
Debugging
Pretraining sources
Evaluation benchmarks
Per-model accuracy on these benchmarks and the downloadable pretrained weights are listed on the Depth Estimation task page. A dataset YAML whose train field lists multiple image directories combines these sources for large-scale mixed training.
images/train and images/val.depth/train and depth/val folders using the same file stem as the image. Use save_depth_png() to convert meter arrays into compact millimeter PNGs.0 or negative values.path, train, val, nc: 1, and names: {0: depth}.path: path/to/my-depth-dataset
train: images/train
val: images/val
nc: 1
names:
0: depth
# Optional: PNG integer units per meter (default 1000)
depth_scale: 1000
Use scaled 16-bit grayscale PNGs for compact datasets. By default each integer step is one millimeter; set depth_scale in the dataset YAML for another scale. ultralytics.data.utils.save_depth_png() converts meter arrays to the default format. Floating-point NPY maps in meters also work directly.
Pixels with depth values ≤ 0 are treated as invalid and masked out from both loss computation and metric evaluation. This covers sensor noise, sky regions, and reflective surfaces where depth cannot be reliably measured.
Depth estimation validation reports the standard Depth Anything metric set:
Yes. Each depth .png or .npy file must share the same stem as the corresponding image. The loader derives the depth path by replacing the images directory component with depth, preferring PNG and falling back to NPY. Images whose depth file is missing or unreadable are dropped during the cached dataset scan with a warning.