|
| 1 | +# FMPose3D Inference API |
| 2 | + |
| 3 | +## Overview |
| 4 | +This inference API provides a high-level, end-to-end interface for monocular 3D pose estimation using flow matching. It wraps the full pipeline — input ingestion, 2D keypoint detection, and 3D lifting — behind a single `FMPose3DInference` class, supporting both **human** (17-joint H36M) and **animal** (26-joint Animal3D) skeletons. Model weights are downloaded automatically from HuggingFace when not provided locally. |
| 5 | + |
| 6 | +--- |
| 7 | + |
| 8 | + |
| 9 | +## Quick Examples |
| 10 | + |
| 11 | +**Human pose estimation (end-to-end):** |
| 12 | + |
| 13 | +```python |
| 14 | +from fmpose3d import FMPose3DInference, FMPose3DConfig |
| 15 | + |
| 16 | +# Create a config (optional) |
| 17 | +config = FMPose3DConfig(model_type="fmpose3d_humans") # or "fmpose3d_animals" |
| 18 | + |
| 19 | +# Initialize the API |
| 20 | +api = FMPose3DInference(config) # weights auto-downloaded |
| 21 | + |
| 22 | +# Predict from source (path, or an image array) |
| 23 | +result = api.predict("photo.jpg") |
| 24 | +print(result.poses_3d.shape) # (1, 17, 3) |
| 25 | +print(result.poses_3d_world.shape) # (1, 17, 3) |
| 26 | +``` |
| 27 | + |
| 28 | +**Human pose estimation (two-step):** |
| 29 | + |
| 30 | +```python |
| 31 | +from fmpose3d import FMPose3DInference |
| 32 | + |
| 33 | +api = FMPose3DInference(model_weights_path="weights.pth") |
| 34 | + |
| 35 | +# The 2D and 3D inference step can be called separately |
| 36 | +result_2d = api.prepare_2d("photo.jpg") |
| 37 | +result_3d = api.pose_3d(result_2d.keypoints, result_2d.image_size) |
| 38 | +``` |
| 39 | + |
| 40 | +**Animal pose estimation:** |
| 41 | + |
| 42 | +```python |
| 43 | +from fmpose3d import FMPose3DInference |
| 44 | + |
| 45 | +# The api has a convenience method for loading directly with the animal config |
| 46 | +api = FMPose3DInference.for_animals() |
| 47 | +result = api.predict("dog.jpg") |
| 48 | +print(result.poses_3d.shape) # (1, 26, 3) |
| 49 | +``` |
| 50 | + |
| 51 | + |
| 52 | +## API Documentation |
| 53 | + |
| 54 | +### `FMPose3DInference` — Main Inference Class |
| 55 | + |
| 56 | +The high-level entry point. Manages the full pipeline: input ingestion, 2D estimation, and 3D lifting. |
| 57 | + |
| 58 | +#### Constructor |
| 59 | + |
| 60 | +```python |
| 61 | +FMPose3DInference( |
| 62 | + model_cfg: FMPose3DConfig | None = None, |
| 63 | + inference_cfg: InferenceConfig | None = None, |
| 64 | + model_weights_path: str | Path | None = None, |
| 65 | + device: str | torch.device | None = None, |
| 66 | + *, |
| 67 | + estimator_2d: HRNetEstimator | SuperAnimalEstimator | None = None, |
| 68 | + postprocessor: HumanPostProcessor | AnimalPostProcessor | None = None, |
| 69 | +) |
| 70 | +``` |
| 71 | + |
| 72 | +| Parameter | Description | |
| 73 | +|---|---| |
| 74 | +| `model_cfg` | Model architecture settings. Defaults to human (17 H36M joints). | |
| 75 | +| `inference_cfg` | Inference settings (sample steps, test augmentation, etc.). | |
| 76 | +| `model_weights_path` | Path to a `.pth` checkpoint. `None` triggers automatic download from HuggingFace. | |
| 77 | +| `device` | Compute device. `None` auto-selects CUDA if available. | |
| 78 | +| `estimator_2d` | Override the 2D pose estimator (auto-selected by default). | |
| 79 | +| `postprocessor` | Override the post-processor (auto-selected by default). | |
| 80 | + |
| 81 | +#### `FMPose3DInference.for_animals(...)` — Class Method |
| 82 | + |
| 83 | +```python |
| 84 | +@classmethod |
| 85 | +def for_animals( |
| 86 | + cls, |
| 87 | + model_weights_path: str | None = None, |
| 88 | + *, |
| 89 | + device: str | torch.device | None = None, |
| 90 | + inference_cfg: InferenceConfig | None = None, |
| 91 | +) -> FMPose3DInference |
| 92 | +``` |
| 93 | + |
| 94 | +Convenience constructor for the **animal** pipeline. Sets `model_type="fmpose3d_animals"`, loads the appropriate config (26-joint Animal3D skeleton) and disables flip augmentation by default. |
| 95 | + |
| 96 | +--- |
| 97 | + |
| 98 | +### Public Methods |
| 99 | + |
| 100 | +#### `predict(source, *, camera_rotation, seed, progress)` → `Pose3DResult` |
| 101 | + |
| 102 | +End-to-end prediction: 2D estimation followed by 3D lifting in a single call. |
| 103 | + |
| 104 | +| Parameter | Type | Description | |
| 105 | +|---|---|---| |
| 106 | +| `source` | `Source` | Image path, directory, numpy array `(H,W,C)` or `(N,H,W,C)`, or list thereof. Video files are not supported. | |
| 107 | +| `camera_rotation` | `ndarray \| None` | Length-4 quaternion for camera-to-world rotation. Defaults to the official demo rotation. `None` skips the transform. Ignored for animals. | |
| 108 | +| `seed` | `int \| None` | Seed for reproducible sampling. | |
| 109 | +| `progress` | `ProgressCallback \| None` | Callback `(current_step, total_steps) -> None`. | |
| 110 | +
|
| 111 | +**Returns:** `Pose3DResult` |
| 112 | + |
| 113 | +--- |
| 114 | + |
| 115 | +#### `prepare_2d(source, progress)` → `Pose2DResult` |
| 116 | + |
| 117 | +Runs only the 2D pose estimation step. |
| 118 | + |
| 119 | +| Parameter | Type | Description | |
| 120 | +|---|---|---| |
| 121 | +| `source` | `Source` | Same flexible input as `predict()`. | |
| 122 | +| `progress` | `ProgressCallback \| None` | Optional progress callback. | |
| 123 | +
|
| 124 | +**Returns:** `Pose2DResult` containing `keypoints`, `scores`, and `image_size`. |
| 125 | + |
| 126 | +--- |
| 127 | + |
| 128 | +#### `pose_3d(keypoints_2d, image_size, *, camera_rotation, seed, progress)` → `Pose3DResult` |
| 129 | + |
| 130 | +Lifts pre-computed 2D keypoints to 3D using the flow-matching model. |
| 131 | + |
| 132 | +| Parameter | Type | Description | |
| 133 | +|---|---|---| |
| 134 | +| `keypoints_2d` | `ndarray` | Shape `(num_persons, num_frames, J, 2)` or `(num_frames, J, 2)`. First person is used if 4D. | |
| 135 | +| `image_size` | `tuple[int, int]` | `(height, width)` of the source frames. | |
| 136 | +| `camera_rotation` | `ndarray \| None` | Camera-to-world quaternion (human only). | |
| 137 | +| `seed` | `int \| None` | Seed for reproducible results. | |
| 138 | +| `progress` | `ProgressCallback \| None` | Per-frame progress callback. | |
| 139 | +
|
| 140 | +**Returns:** `Pose3DResult` |
| 141 | + |
| 142 | +--- |
| 143 | + |
| 144 | +#### `setup_runtime()` |
| 145 | + |
| 146 | +Manually initializes all runtime components (2D estimator, 3D model, weights). Called automatically on first use of `predict`, `prepare_2d`, or `pose_3d`. |
| 147 | + |
| 148 | +--- |
| 149 | + |
| 150 | +### Types & Data Classes |
| 151 | + |
| 152 | +### `Source` |
| 153 | + |
| 154 | +Accepted source types for `FMPose3DInference.predict` and `prepare_2d`: |
| 155 | + |
| 156 | +- `str` or `Path` — path to an image file or a directory of images. |
| 157 | +- `np.ndarray` — a single frame `(H, W, C)` or a batch `(N, H, W, C)`. |
| 158 | +- `list` — a list of file paths or a list of `(H, W, C)` arrays. |
| 159 | + |
| 160 | +```python |
| 161 | +Source = Union[str, Path, np.ndarray, Sequence[Union[str, Path, np.ndarray]]] |
| 162 | +``` |
| 163 | + |
| 164 | +#### `Pose2DResult` |
| 165 | + |
| 166 | +| Field | Type | Description | |
| 167 | +|---|---|---| |
| 168 | +| `keypoints` | `ndarray` | 2D keypoints, shape `(num_persons, num_frames, J, 2)`. | |
| 169 | +| `scores` | `ndarray` | Per-joint confidence, shape `(num_persons, num_frames, J)`. | |
| 170 | +| `image_size` | `tuple[int, int]` | `(height, width)` of source frames. | |
| 171 | + |
| 172 | +#### `Pose3DResult` |
| 173 | + |
| 174 | +| Field | Type | Description | |
| 175 | +|---|---|---| |
| 176 | +| `poses_3d` | `ndarray` | Root-relative 3D poses, shape `(num_frames, J, 3)`. | |
| 177 | +| `poses_3d_world` | `ndarray` | Post-processed 3D poses, shape `(num_frames, J, 3)`. For humans: world-coordinate poses. For animals: limb-regularized poses. | |
| 178 | + |
| 179 | + |
| 180 | + |
| 181 | +--- |
| 182 | + |
| 183 | +### 2D Estimators |
| 184 | + |
| 185 | +#### `HRNetEstimator(cfg: HRNetConfig | None)` |
| 186 | + |
| 187 | +Default 2D estimator for the human pipeline. Wraps HRNet + YOLO with a COCO → H36M keypoint conversion. |
| 188 | + |
| 189 | +- `setup_runtime()` — Loads YOLO + HRNet models. |
| 190 | +- `predict(frames: ndarray)` → `(keypoints, scores)` — Returns H36M-format 2D keypoints from BGR frames `(N, H, W, C)`. |
| 191 | + |
| 192 | +#### `SuperAnimalEstimator(cfg: SuperAnimalConfig | None)` |
| 193 | + |
| 194 | +2D estimator for the animal pipeline. Uses DeepLabCut SuperAnimal and maps quadruped80K keypoints to the 26-joint Animal3D layout. |
| 195 | + |
| 196 | +- `setup_runtime()` — No-op (DLC loads lazily). |
| 197 | +- `predict(frames: ndarray)` → `(keypoints, scores)` — Returns Animal3D-format 2D keypoints from BGR frames. |
| 198 | + |
| 199 | +--- |
| 200 | + |
| 201 | +### Post-Processors |
| 202 | + |
| 203 | +#### `HumanPostProcessor` |
| 204 | + |
| 205 | +Zeros the root joint (root-relative) and applies `camera_to_world` rotation. |
| 206 | + |
| 207 | +#### `AnimalPostProcessor` |
| 208 | + |
| 209 | +Applies limb regularization (rotates the pose so that average limb direction is vertical). No root zeroing or camera-to-world transform. |
| 210 | + |
| 211 | +--- |
| 212 | + |
| 213 | + |
| 214 | + |
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