Tuesday, 16 June 2015


Hi all,
as I promised, we are back with new post in ATOR. We start today with an experiment we wanted to do since long: a comparison between two Structure from Motion - Muti View Stereoreconstruction (SfM - MVS) suite. The first is Python Photogrammetry Toolbox, developed by +Pierre Moulon some years ago and integrated in ArcheOS 4 (Caesar) with the new GUI (PPT-GUI) written in Python by +Alessandro Bezzi and me. The second one is the evolution of PPT: openMVG, which Pierre is developing since some years and that will be integrated in the next releases of ArcheOS.
Our small test regarded just four pictures taken with a Nikon D5000 on an old excavation. We want to point out the speed of the overall process in OpenMVG, which gave a result compatible with the one of PPT.
In the image below you can have an overview (in +MeshLab) of the two pointclouds generated bye the different software: openMVG processed a ply file with 391197 points, while PPT gave us a result with 425296 points.

Comparison of the two models generated by opnMVG and PPT

The main different stays in the processing time. In fact, while PPT needed 16 minutes, 11 seconds and 25 tenths, openMVG complete the model in just 3 minutes, 28 seconds and 20 tenths.
Here below I report the log file of openMVG, where you can see each step of the process:

STEP 1: Process Intrisic analysis - openMVG_main_CreateList took: 00:00:00:00.464
STEP 2: Process compute matches - openMVG_main_computeMatches took: 00:00:01:13.73764
STEP 3: Process Incremental Reconstruction -  openMVG_main_IncrementalSfM took: 00:00:00:47.47717
STEP 4: Process Export to CMVS-PMVS - openMVG_main_openMVG2PMVS took: 00:00:00:00.352
STEP 4: Process Export to CMVS-PMVS - openMVG_main_openMVG2PMVS took: 00:00:00:00.352
STEP 5: Process CMVS-PMVS took: 00:00:01:25.85958
The whole detection and 3D reconsruction process took: 00:00:03:28.208258

We will go on in working and testing openMVG, hopfully posting soon news about this nice software.

Have a nice day!


Many thanks to +Pierre Moulon and +CĂ­cero Moraes for the help!
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