Merge pull request #238 from smathermather/add-time-sift

Add time sift

Author: smathermather

source/map-accuracy.rst

@@ -269,6 +269,90 @@ When previously mapped sites need revisited, OpenDroneMap can align multiple ver
 
 Animated gif comparing two separately processed, but aligned digital surface models.
 
+Plugin Time-SIFT
+----------------
+
+The script at contrib/time-sift in the ODM repository does Time-SIFT processing with ODM. Time-SIFT is a method for multi-temporal analysis without the need to co-registrate the data.
+
+   D. Feurer, F. Vinatier, Joining multi-epoch archival aerial images in
+   a single SfM block allows 3-D change detection with almost
+   exclusively image information, ISPRS Journal of Photogrammetry and
+   Remote Sensing, Volume 146, 2018, Pages 495-506, ISSN 0924-2716, doi:
+   10.1016/j.isprsjprs.2018.10.016
+   (https://doi.org/10.1016/j.isprsjprs.2018.10.016)
+
+Requirements
+============
+
+-  ODM ! :-)
+-  subprocess
+-  json
+-  os
+-  shutil
+-  pathlib
+-  sys
+-  argparse
+-  textwrap
+
+Usage
+=====
+
+Provided example
+================
+
+Download or clone `this repo <https://forge.inrae.fr/Denis.Feurer/timesift-odm-data-example.git>`__
+to get example data.
+
+Then execute
+
+::
+
+   python Timesift_odm.py datasets --end-with odm_filterpoints
+
+It should make the Time-SIFT processing on the downloaded example data, stopping after the filtered dense clouds step.
+
+In the destination dir, you should obtain new directories, ``0_before`` and ``1_after`` at the same level as the ``time-sift-block`` directory. These new directories contain all the results natively co-registered.
+
+You can then use `CloudCompare <https://cloudcompare.org/>`__ to compute distance between the ``datasets/0_before/odm_filterpoints/point_cloud.ply`` and the ``datasets/1_after/odm_filterpoints point_cloud.ply`` and obtain this image showing the difference between the two 3D surfaces. Here, two soil samples were excavated as can be seen on the image below. |image1|
+
+Your own data
+~~~~~~~~~~~~~
+
+In your dataset directory (usually ``datasets``, but you can have chosen another name) you have to prepare a Time-SIFT project directory (default name : ``time-sift-block``, *can be tuned via a parameter*) that contains : \* ``images/`` : a subdirectory with all images of all epochs. This directory name is fixed as it is the one expected by ODM \*
+``images_epochs.txt`` : a file that has the same format as the file used for the split and merge ODM function. This file name *can be tuned via a parameter*.
+
+The ``images_epochs.txt`` file has two columns, the first column contains image names and the second contains the epoch name as follows
+
+::
+
+   DSC_0368.JPG 0_before
+   DSC_0369.JPG 0_before
+   DSC_0370.JPG 0_before
+   DSC_0389.JPG 1_after
+   DSC_0390.JPG 1_after
+   DSC_0391.JPG 1_after
+
+Your directory, before running the script, should look like this :
+
+::
+
+   $PWD/datasets/
+   └── time-sift-block/
+       ├── images/
+       └── images_epochs.txt
+
+At the end of the script you obtain a directory by epoch (at the same level as the Time-SIFT project directory). Each directory is processed with images of each epoch and all results are natively co-registered due to the initial sfm step done with all images.
+
+::
+
+   $PWD/datasets/
+   ├── 0_before/
+   ├── 1_after/
+   └── time-sift-block/
+
+.. |image1| image:: https://forge.inrae.fr/Denis.Feurer/timesift-odm-data-example/-/raw/main/Example.png?ref_type=heads
+
+
 -----------------------
 Aligning Large  Datasets
 -----------------------