# Copyright 2022 AI Singapore
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# https://www.apache.org/licenses/LICENSE-2.0
#
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"""
Estimates the 3D coordinates of an object given a 2D bounding box.
"""
from typing import Any, Dict
import numpy as np
from peekingduck.pipeline.nodes.abstract_node import AbstractNode
[docs]class Node(AbstractNode):
"""Uses 2D bounding boxes information to estimate 3D location.
Inputs:
|bboxes_data|
Outputs:
|obj_3D_locs_data|
Configs:
focal_length (:obj:`float`): **default = 1.14**. |br|
Approximate focal length of webcam used, in metres. Example on
measuring focal length can be found `here <https://learnopencv.com
/approximate-focal-length-for-webcams-and-cell-phone-cameras/>`_.
height_factor (:obj:`float`): **default = 2.5**. |br|
A factor used to estimate real-world distance from pixels, based on
average human height in metres. The value varies across different
camera set-ups, and calibration may be required. Please refer to
the :ref:`Social Distancing use case
<use_case_social_distancing_using_object_detection>` for more
information.
"""
def __init__(self, config: Dict[str, Any] = None, **kwargs: Any) -> None:
super().__init__(config, node_path=__name__, **kwargs)
def run(self, inputs: Dict[str, Any]) -> Dict[str, Any]:
"""Converts 2D bounding boxes into 3D locations."""
locations = []
for bbox in inputs["bboxes"]:
# Subtraction is to make the camera the origin of the coordinate system
center_2d = ((bbox[0:2] + bbox[2:4]) * 0.5) - np.array([0.5, 0.5])
bbox_height = bbox[3] - bbox[1]
z_coord = (self.focal_length * self.height_factor) / bbox_height
x_coord = (center_2d[0] * self.height_factor) / bbox_height
y_coord = (center_2d[1] * self.height_factor) / bbox_height
point = np.array([x_coord, y_coord, z_coord])
locations.append(point)
outputs = {"obj_3D_locs": locations}
return outputs
def _get_config_types(self) -> Dict[str, Any]:
"""Returns dictionary mapping the node's config keys to respective types."""
return {"focal_length": float, "height_factor": float}