tao-train-foundation-stereo

---

name: tao-train-foundation-stereo description: Stereo depth estimation using FoundationStereo. Predicts disparity maps from stereo image pairs for 3D reconstruction. Use when training, evaluating, exporting, or running inference for a TAO FoundationStereo model. Trigger phrases include "train stereo depth", "FoundationStereo", "stereo disparity estimation", "3D reconstruction from stereo". license: Apache-2.0 compatibility: Requires docker + nvidia-container-toolkit. metadata: version: "0.1.0" author: NVIDIA Corporation allowed-tools: Read Bash tags:

• stereo
• depth
• estimation

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Depth Net Stereo

Standalone install? If this session was not initialized by the TAO skill bank plugin, run the tao-setup skill first (host preflight, credentials, cross-skill discovery).

Stereo depth estimation using FoundationStereo architecture. Predicts disparity maps from stereo image pairs for 3D reconstruction.

Uses pretrained Depth Anything v2 and EdgeNeXt encoders. Set model.stereo_backbone.depth_anything_v2_pretrained_path and model.stereo_backbone.edgenext_pretrained_path.

The mono and stereo skills both invoke the unified TAO depth_net CLI inside the container; the mono/stereo family is selected via model.model_type (e.g., FoundationStereo).

PyT actions packaged by this model skill: train, evaluate, inference, export, and quantize. The PyT depth_net entrypoint does not accept a gen_trt_engine action in the current TAO image; build TensorRT engines only through the deploy workflow.

For TAO Deploy TensorRT actions (gen_trt_engine, TensorRT evaluate, and TensorRT inference), read references/tao-deploy-foundation-stereo.md first. The deploy spec template lives in this skill's references/spec_template_deploy.yaml.

Train Action Policy

This model is AutoML-enabled at the model layer. Before handling any train-stage request, read references/skill_info.yaml and resolve the run override from either an explicit automl_policy value or the user's workflow request. Use automl_policy: on by default and only expose on / off in new launch prompts. Treat phrases like "turn off AutoML", "disable AutoML", "no HPO", or "plain training" as automl_policy: off for this run only. When automl_policy: on, automl_enabled: true, and both schemas/train.schema.json and references/spec_template_train.yaml are packaged, route the train action through tao-skill-bank:tao-run-automl by default with this model's skill_dir. Preserve workflow/application overrides for datasets, specs, output directories, GPU/platform settings, parent checkpoints, and automl_policy. Use direct model training only when automl_policy: off or the packaged train schema/template is missing; in the missing-schema case, report that AutoML is enabled but not runnable for this model until schemas are generated.

Non-train actions such as evaluate, inference, export, and deploy flows stay in this model skill. The per-run automl_policy override does not change model metadata.

Workflow

Prerequisites — data accessibility

Your dataset (left + right images + GT disparity) must be reachable from inside the container:

• SDK runner: place files at the S3 paths the runner resolves (the S3_TRAIN / S3_EVAL placeholders shown in the spec overrides). The runner handles S3 → container-path mounting transparently.
• Direct docker run (e.g. local testing): mount the host dataset root read-only at the same in-container path:

docker run ... -v <host_data_root>:<host_data_root>:ro <container> ...

The same accessibility requirement applies to the <output_dir> written by all actions.

Step 1 — Annotation file

Per-line annotation file referenced by data_sources[*].data_file:

Columns	Format	Use
2	<left> <right>	Stereo inference (no GT)
3	<left> <right> <disparity>	Stereo with GT
4	<left> <right> <disparity> <occlusion_mask>	Stereo with GT and occlusion mask

If you already have one, point to it. Otherwise generate via depth_net convert:

depth_net convert -e <convert_spec.yaml>

convert_spec.yaml template (stereo):

results_dir: <directory where generated annotation files are written>
data_root: <directory whose immediate children are scene folders that contain your image+depth files; convert walks data_root recursively but expects per-scene subdirectories at one level below>
image_dir_pattern: [<substring matching left image paths>]
right_dir_pattern: [<substring matching right image paths>]
depth_dir_pattern: [<substring matching GT disparity paths>]
nocc_dir_pattern: []                 # optional, occlusion mask paths
image_extension: '.png'  # always include the leading dot
depth_extension: '.png'  # form must match image_extension (the swap is a substring replace)
nocc_extension: ''
split_ratio: 0.0        # 0.0/1.0 = test-only; 0.8 = 80/20 train+val

convert walks data_root recursively, selects paths whose path-string contains all substrings in image_dir_pattern (AND-filter), then derives right / depth / mask paths by replacing image_dir_pattern[0] with the corresponding pattern's first element plus extension swap. Inspect your dataset's directory layout and identify the substrings distinguishing left, right, and GT (e.g. im0 vs im1 vs disp0GT for Middlebury).

Step 2 — Pair model_type and dataset_name based on your data

Prefer the dataset-specific class when your layout matches a supported one — it applies class-specific path conventions, evaluation crops, and (where applicable) occlusion-mask handling. Fall back to GenericDataset only for layouts that do not match any registered class.

Data category	model_type	dataset_name
Middlebury data	FoundationStereo	Middlebury
KITTI data	FoundationStereo	Kitti
ETH3D data	FoundationStereo	Eth3d
FSD synthetic data	FoundationStereo	FSD
IsaacReal synthetic data	FoundationStereo	IsaacRealDataset
Crestereo synthetic data	FoundationStereo	Crestereo
Other / non-canonical layout	FoundationStereo	GenericDataset

Valid dataset_name values for stereo data_sources (case-insensitive): FSD, IsaacRealDataset, Crestereo, Middlebury, Eth3d, Kitti, GenericDataset.

The same dataset_name value applies across train and evaluate actions (all of which use 3-column or 4-column annotations with GT disparity). The deploy-side evaluate action follows the same rule — see references/tao-deploy-foundation-stereo.md. For inference with 2-column annotations (left + right, no GT), use dataset_name: GenericDataset regardless of data layout — the dataset-specific classes (Middlebury / Kitti / Eth3d / FSD / IsaacRealDataset / Crestereo) require 3-column input and reject 2-column annotations at the dataloader level. For inference with 3-column annotations (left + right + GT), the dataset-specific class is fine.

Step 3 — Write spec yaml from the spec overrides

Copy the action block from references/spec-overrides-foundation-stereo.md. Replace:

• model.model_type from Step 2 (typically FoundationStereo)
• dataset.<...>.data_sources[*].dataset_name from Step 2
• dataset.<...>.data_sources[*].data_file with the path from Step 1
• For deploy-side evaluate: enforce dataset.test_dataset.batch_size: 1 (see references/tao-deploy-foundation-stereo.md).

Shape consistency: the crop_size in dataset.test_dataset.augmentation.crop_size should match export.input_height / input_width so the trained-model evaluator and the deploy-side TensorRT evaluator operate at the same shape. Note that crop_size is decorative on the pyt evaluate path but authoritative on the deploy evaluate side — see references/troubleshooting-foundation-stereo.md and references/tao-deploy-foundation-stereo.md.

Fresh-install smoke runs are validated at crop_size: [128, 128] with dataset.max_disparity: 128 and model.max_disparity: 128. Avoid 112×112 crops and avoid setting max_disparity smaller than the square crop side for smoke tests: those combinations can fail inside FoundationStereo with feature-map or loss-mask shape mismatches before a checkpoint is produced.

Data source overrides are mandatory for every action. Each data_sources entry is a dict with two mandatory fields: data_file and dataset_name. See references/spec-overrides-foundation-stereo.md for the per-action dataset-requirements table, every action's override block, and the quantize known-issue note.

Step 4 — Run

Create writable home/cache directories inside the mounted output path before using --user. Some TAO containers do not have an /etc/passwd entry for the host UID, and PyTorch / matplotlib need writable cache paths when running as that UID.

mkdir -p <output_dir>/home \
         <output_dir>/.cache/matplotlib \
         <output_dir>/.cache/torchinductor \
         <output_dir>/.cache/xdg

docker run --gpus 'device=0' --shm-size 16G --shm-size=8g \
  --user "$(id -u):$(id -g)" \
  -e USER="$(id -un)" \
  -e LOGNAME="$(id -un)" \
  -e HOME=<output_dir>/home \
  -e MPLCONFIGDIR=<output_dir>/.cache/matplotlib \
  -e TORCHINDUCTOR_CACHE_DIR=<output_dir>/.cache/torchinductor \
  -e XDG_CACHE_HOME=<output_dir>/.cache/xdg \
  -v <data_root>:<data_root>:ro \
  -v <output_dir>:<output_dir> \
  <container> \
  depth_net <action> -e <spec.yaml>

Without --user "$(id -u):$(id -g)" the container writes outputs as nobody:nogroup, blocking host-side cleanup / retry.

Step 5 — Verify

• Container exit code 0
• status.json kpi block populated
• For train: inspect per-step train_loss directly (the entrypoint reports Execution status: PASS even when loss is NaN)
• For evaluate: rely on epe / bp1 / bp2 / bp3 / d1 / rmse (the evaluator also emits abs_rel / sq_rel / rmse_log which are non-meaningful for stereo — see references/parameters-foundation-stereo.md)
• For inference: artifacts under results_dir

For TAO Deploy TensorRT actions (gen_trt_engine, TensorRT evaluate, and TensorRT inference), read references/tao-deploy-foundation-stereo.md first. Deploy spec templates live in this skill's references/ folder with the spec_template_deploy_*.yaml prefix.

Training Requirements

• AutoML metric contract: when recommendations are scored with the packaged evaluate action, use val/epe with minimize direction.
• Training monitoring metric: val/loss Use this only for live training-loss monitoring.
• AutoML/evaluation KPI: val/epe, minimized. The packaged evaluate action writes this key to status.json; using val/loss as the AutoML objective makes trial metric extraction fail. Its Lightning console table labels the same evaluator output test/epe, so compare AutoML's recorded val/epe value with the console's test/epe value when verifying a run.
• Recommended AutoML train parameters: train.optim.lr and train.optim.weight_decay. Do not search validation/test/inference augmentation fields, and do not search model.volume_dim because the current implementation does not consume it.
• Eval dataset: optional. Val dataset configured via dataset.val_dataset.data_sources (each entry needs data_file and dataset_name).

See references/spec-overrides-foundation-stereo.md for the per-action dataset-requirements table and every action's mandatory data-source override block.

Parameters, Metrics, Multi-GPU, Export/TRT, Hardware

See references/parameters-foundation-stereo.md for the full Important Parameters list (incl. model.encoder vits override, model.max_disparity default 416, model.volume_dim no-op note, dataset.baseline, dataset.focal_x, train.precision, export.batch_size), the Evaluation Metrics table, Multi-GPU / Multi-Node launch keys, Export / TRT Defaults (opset_version/on_cpu pairing, NGC 576×960 settings), and Hardware requirements.

Error Patterns and Troubleshooting

See references/troubleshooting-foundation-stereo.md for disparity overflow, smoke-test shape mismatch, missing pretrained paths, the encoder / dataset_name struct errors, the depth_net_stereo: not found entrypoint note, the pyt-vs-deploy crop_size discussion, and the deploy evaluate scalar-conversion failure.

Spec Param / Parent Model Inference

See references/checkpoint-inference-mappings-foundation-stereo.md for the checkpoint-resolution rules (model_epoch_<epoch>_step_<step>.pth, dn_model_latest.pth policy), the absence of parent PyT gen_trt_engine, and the full per-action inference-mapping table from depth_net_stereo.config.json (including parent_model / parent_job_id resolution).

Deployment

• tao-deploy-foundation-stereo