Skip to content

Commit

Permalink
migrate image_pipeline docs
Browse files Browse the repository at this point in the history
  • Loading branch information
mikeferguson committed Feb 5, 2024
1 parent 506bed2 commit f146a41
Show file tree
Hide file tree
Showing 9 changed files with 374 additions and 4 deletions.
5 changes: 3 additions & 2 deletions depth_image_proc/doc/index.rst
Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
depth_image_proc
================
Overview
========

``depth_image_proc`` provides basic processing for depth images, much as
``image_proc`` does for traditional 2D images. The two packages are
Expand Down Expand Up @@ -28,6 +28,7 @@ For an example of ``depth_image_proc`` in practice, examine the contents of
.. toctree::
:maxdepth: 2

self
components
tutorials
changes
Expand Down
111 changes: 111 additions & 0 deletions image_pipeline/doc/camera_info.rst
Original file line number Diff line number Diff line change
@@ -0,0 +1,111 @@
.. _Camera Info:

Camera Info
===========

Camera Coordinate System
------------------------
Below is a diagram of the camera coordinate system assumed by the
CameraInfo message. It is a right-handed system, with the world X
and Y aligned with the image x and y. This is the same coordinate
system used in OpenCV. It differs from the coordinate system of
Harley and Zisserman, which has Z forward, Y up, and X to the
left (looking towards +Z).

|coords|

.. |coords| image:: images/CameraCoords.png

Derivation Diagram
------------------

Below is a diagram of the various images that are conceptually
derivable from the CameraInfo message. The boxed variables are
present in this message.

|camera_info|

.. |camera_info| image:: images/CameraInfo.png

Projection Onto the Original Image
----------------------------------
Starting with an initial 3D point X, the position of the corresponding
image point is found by going right-to-left in the upper half of the
diagram. The process is summarized by the following equations.

.. code-block:: text
X' = [R,t]X transform
sx = X' projection
x* = d(x) distortion
q = Kx* pixel coordinates
This process uses the K camera matrix and D distortion vector from CameraInfo.
Ignoring the transform T, you can find the projection of a point X' into the
original camera frame using these equations. First, the 3D point X' is
projected onto the normalized, undistorted image via a projection operation
(division by Z). Then the distortion coefficients are used in the function
d() to move the point to its distorted position, still in a normalized image.
Finally, the normalized image is converted to a pixel-coordinate image by
applying the camera matrix to each image point.

Rectification
-------------
Rectification is the process of transforming the input image into an output
image with the distortion corrected, and optionally the normalized image plane
transformed by rotation, optinain-image-plane translation, and optionally
in-image-plane scale.

Simple Monocular Rectification
------------------------------
In this case, there is a monocular device with distortion correction only.
To transform a pixel in the input image into one in the output image, it is
sent through the K - D - R - K' series of transformations. K - D gets to the
normalized, undistorted image; the rotation R is the identity because we
don't want to rotate the normalized undistorted image; and then K' converts
back to pixel coordinates in the output image. In this case, since there is
no need of in-image-plane translation, or scaling from the original image,
so K = K' , and only the K and D elements of CameraInfo are needed.
The ``camera_calibration`` package does monocular calibration to get K'
using OpenCV's getOptimalNewCameraMatrix() function with argument
'alpha'=0.0 that cause K' ≠ K.

Projection onto the output image is by the P matrix, which is formed from K'
and the optional rotation and translation, in this case the identity and 0,
respectively. So if K' = K, P is redundant information, and could be formed
directly from K.

Stereo and Complex Monocular Rectification
------------------------------------------
After getting normalized undistorted image using K and D, here we apply a
transformation to the normalized, undistorted image: each points on this
image is rotated by R and then is passed to K' get the correspondent pixel
coordinate on the output image which is translated and scaled by K' with
respect to the original image. This transformation is important, for example,
in aligning two images of a stereo pair to lie in the same plane and have
coincident epipolar lines.

The transform of a pixel from the input to output image is the same as in
the simple monocular case, except that R need not be the identity, and K'
need not be equal to K. As a consequence, the normalized undistorted image
can be rotated in 3D space, and the output image can be translated, scaled
relative to the original image.

The projection matrix has an additional parameter, a translational offset t.
This parameter is used in the right stereo camera to reflect its external
position relative to the left camera. Since the point X in left camera
frame is transformed to the right camera by [I|t], that means the position
of the left camera frame origin with respect to the right camera frame is
given by the vector t in the right camera frame.

Putting this all together, the projection matrix for the rectified output
image is given by:

.. code-block:: text
P = K' [I|t].
Note that in this case the internal camera parameters of the output image,
K', can be different from the input image, so P cannot be formed just
from K and D. And the I is the 3x3 rotation matrix representing left
camera frame in the right, not the identity.
193 changes: 193 additions & 0 deletions image_pipeline/doc/conf.py
Original file line number Diff line number Diff line change
@@ -0,0 +1,193 @@
# Copyright 2024 Open Source Robotics Foundation, Inc.
#
# 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
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

# -*- coding: utf-8 -*-
#
# Configuration file for the Sphinx documentation builder.
#
# This file does only contain a selection of the most common options. For a
# full list see the documentation:
# http://www.sphinx-doc.org/en/master/config

# -- Path setup --------------------------------------------------------------

# If extensions (or modules to document with autodoc) are in another directory,
# add these directories to sys.path here. If the directory is relative to the
# documentation root, use os.path.abspath to make it absolute, like shown here.
import os
import sys
sys.path.insert(0, os.path.abspath('.'))


# -- Project information -----------------------------------------------------

project = 'image_pipeline'
copyright = '2008-2024, Open Source Robotics Foundation, Inc.' # noqa
author = 'Open Source Robotics Foundation, Inc.'

# The short X.Y version
version = ''
# The full version, including alpha/beta/rc tags
release = '3.2.1'


# -- General configuration ---------------------------------------------------

# If your documentation needs a minimal Sphinx version, state it here.
#
# needs_sphinx = '1.0'

# Add any Sphinx extension module names here, as strings. They can be
# extensions coming with Sphinx (named 'sphinx.ext.*') or your custom
# ones.
extensions = [
'sphinx.ext.autodoc',
'sphinx.ext.autosummary',
'sphinx.ext.doctest',
'sphinx.ext.coverage',
'sphinx_rtd_theme',
]

# Add any paths that contain templates here, relative to this directory.
templates_path = ['_templates']

# The suffix(es) of source filenames.
# You can specify multiple suffix as a list of string:
#
# source_suffix = ['.rst', '.md']
source_suffix = '.rst'

# The master toctree document.
master_doc = 'index'

# The language for content autogenerated by Sphinx. Refer to documentation
# for a list of supported languages.
#
# This is also used if you do content translation via gettext catalogs.
# Usually you set "language" from the command line for these cases.
language = None

# List of patterns, relative to source directory, that match files and
# directories to ignore when looking for source files.
# This pattern also affects html_static_path and html_extra_path.
exclude_patterns = []

# The name of the Pygments (syntax highlighting) style to use.
pygments_style = None


# -- Options for HTML output -------------------------------------------------

# The theme to use for HTML and HTML Help pages. See the documentation for
# a list of builtin themes.
#
html_theme = 'sphinx_rtd_theme'

# Theme options are theme-specific and customize the look and feel of a theme
# further. For a list of options available for each theme, see the
# documentation.
#
# html_theme_options = {}

# Add any paths that contain custom static files (such as style sheets) here,
# relative to this directory. They are copied after the builtin static files,
# so a file named "default.css" will overwrite the builtin "default.css".
html_static_path = []

# Custom sidebar templates, must be a dictionary that maps document names
# to template names.
#
# The default sidebars (for documents that don't match any pattern) are
# defined by theme itself. Builtin themes are using these templates by
# default: ``['localtoc.html', 'relations.html', 'sourcelink.html',
# 'searchbox.html']``.
#
# html_sidebars = {}


# -- Options for HTMLHelp output ---------------------------------------------

# Output file base name for HTML help builder.
htmlhelp_basename = 'image_pipeline_doc'


# -- Options for LaTeX output ------------------------------------------------

latex_elements = {
# The paper size ('letterpaper' or 'a4paper').
#
# 'papersize': 'letterpaper',

# The font size ('10pt', '11pt' or '12pt').
#
# 'pointsize': '10pt',

# Additional stuff for the LaTeX preamble.
#
# 'preamble': '',

# Latex figure (float) alignment
#
# 'figure_align': 'htbp',
}


# -- Options for manual page output ------------------------------------------

# One entry per manual page. List of tuples
# (source start file, name, description, authors, manual section).
man_pages = [
(master_doc, 'image_pipeline', 'image_pipeline Documentation',
[author], 1)
]


# -- Options for Texinfo output ----------------------------------------------

# Grouping the document tree into Texinfo files. List of tuples
# (source start file, target name, title, author,
# dir menu entry, description, category)
texinfo_documents = [
(master_doc, 'image_pipeline', 'image_pipeline Documentation',
author, 'image_pipeline', 'ROS 2 components for image processing.',
'Miscellaneous'),
]


# -- Options for Epub output -------------------------------------------------

# Bibliographic Dublin Core info.
epub_title = project

# The unique identifier of the text. This can be a ISBN number
# or the project homepage.
#
# epub_identifier = ''

# A unique identification for the text.
#
# epub_uid = ''

# A list of files that should not be packed into the epub file.
epub_exclude_files = ['search.html']


# -- Extension configuration -------------------------------------------------

autoclass_content = 'both'

autodoc_default_options = {
'members': True, # document members
'undoc-members': True, # also document members without documentation
}
Binary file added image_pipeline/doc/images/CameraCoords.png
Loading
Sorry, something went wrong. Reload?
Sorry, we cannot display this file.
Sorry, this file is invalid so it cannot be displayed.
Binary file added image_pipeline/doc/images/CameraInfo.png
Loading
Sorry, something went wrong. Reload?
Sorry, we cannot display this file.
Sorry, this file is invalid so it cannot be displayed.
43 changes: 43 additions & 0 deletions image_pipeline/doc/index.rst
Original file line number Diff line number Diff line change
@@ -0,0 +1,43 @@
Overview
========

The ``image_pipeline`` stack is designed to process raw camera images
into useful inputs to vision algorithms: rectified mono/color images,
stereo disparity images, and stereo point clouds. Components include:

* **Calibration**: Cameras must be calibrated in order to relate the
images they produce to the three-dimensional world. The
``camera_calibration`` package provides tools to calibrate monocular
and stereo cameras in your ROS system. The :ref:`Camera Info` page
provides a detailed description of the parameters used by the
pipeline.
* **Monocular processing**: The raw image stream can be piped through
the ``image_proc`` node to remove camera distortion. The node also
performs color interpolation for Bayer pattern color cameras.
* **Stereo processing**: The ``stereo_image_proc`` package performs
the duties of ``image_proc`` for a pair of cameras co-calibrated
for stereo vision. It also uses stereo processing to produce
disparity images and point clouds.
* **Depth processing**: ``depth_image_proc`` provides components
for processing depth images (as produced by the Kinect,
time-of-flight cameras, etc.), such as producing point clouds.
* **Visualization**: The ``image_view`` package provides a lightweight
alternative to ``rviz2`` for viewing an image topic. It also includes
a ``stereo_view`` tool for viewing stereo pairs and disparity images.

.. toctree::
:maxdepth: 2

self
camera_info
camera_calibration <../camera_calibration/index.html#http://>
depth_image_proc <../depth_image_proc/index.html#http://>
image_proc <../image_proc/index.html#http://>
image_view <../depth/image_view/index.html#http://>
stereo_image_proc <../depth/stereo_image_proc/index.html#http://>

Indices and tables
==================

* :ref:`genindex`
* :ref:`search`
1 change: 1 addition & 0 deletions image_pipeline/package.xml
Original file line number Diff line number Diff line change
Expand Up @@ -34,5 +34,6 @@

<export>
<build_type>ament_cmake</build_type>
<rosdoc2>rosdoc2.yaml</rosdoc2>
</export>
</package>
20 changes: 20 additions & 0 deletions image_pipeline/rosdoc2.yaml
Original file line number Diff line number Diff line change
@@ -0,0 +1,20 @@
type: 'rosdoc2 config'
version: 1

---

settings:
generate_package_index: false
always_run_doxygen: false
enable_breathe: false
enable_exhale: false
always_run_sphinx_apidoc: false
override_build_type: 'ament_python'
python_source: 'doc'

builders:
- sphinx: {
name: 'image_pipeline',
sphinx_sourcedir: 'doc',
output_dir: ''
}
Loading

0 comments on commit f146a41

Please sign in to comment.