GSoC 2014 Proposal:
​http://www.google-melange.com/gsoc/proposal/public/google/gsoc2014/martidi/5629499534213120

Project Git repository:
​https://github.com/martidi/OSSIM-GSoC-2014.git

Weekly Report 1 (2014, May 23)

Bonding period:

I have configured and built OSSIM in Ubuntu 12.04 OS and tried to built it also in Mac OS.

I have configured, compiled and installed the OpenCV library.

In accordance with mentors, I have decided the programming language.

I have read the documentation and I have begun to familiarize with some OSSIM plugins.

Week 1:

WHAT I GET DONE THIS WEEK:

I have prepared the wiki page (​http://trac.osgeo.org/ossim/wiki/GSoC_2014) and the Git repository (​https://github.com/martidi/OSSIM-GSoC-2014.git) for code hosting.

I have begun to setting up the ossim preferences file, in particular for the ossimopencv_plugin loading.

In accordance with mentors I have begun to see how OSSIM Geocell and the OpenCV library can integrate: I have compiled and installed the ossimopencv_plugin and loaded it in the OSSIM core library in order to analyze how OpenCV is so far used for automatic Tie Points extraction.

I have begun to analyze the ossimRpcModel class.

WHAT I PLAN ON DOING NEXT WEEK:

To solve the problem on which I am stuck.

To complete the ossimRpcModel class analysis.

To test and control implementation efficacy – discuss results with mentors.

SOMETHING ON WHICH I AM BLOCKED:

I have had some problems with satellite imagery loading: it seems that there are some issues for some particular images (e.g. images taken from IKONOS2 and Geoeye) with the ossimRpcModel class; as mentors pointed out this is probably due for some settings in the preferences file.

Weekly Report 2 (2014, May 30)

Week 2:

WHAT I GET DONE THIS WEEK:

I have created the Eclipse project for OSSIM to manage all the source code.

I have set up the ossim preferences file with the elevation information to try to solve the image loading problems and in order to prepare the proper files to begin using the orthorectification tool (ossim-orthoigen).

I have studied the code of the ossim-orthoigen tool and of the associated class ossimOrthoIGen in order to understand their implementation.

I have begun to write the ossim-epipolar app that is based on ossim-orthoigen tool and on the ossim OpenCv plugin. The algorithm for the quasi-epipolar images generation consists of two main steps: first it is necessary to project the raw images on an horizontal plane at a median height of the area of interest and subsequently it is required to search automatically Tie points to minimize the residual parallax error between the two images.

WHAT I PLAN ON DOING NEXT WEEK:

To solve the problem on which I am stuck.

To continue the ossim-epipolar tool implementation.

To verify and assess the automatic Tie Points collection.

To test and control implementation efficacy – discuss results with mentors.

SOMETHING ON WHICH I AM BLOCKED:

Despite I have worked on the preferences file and on image histogram remapping I still have problems in loading some particular images (e.g. images taken from IKONOS2 and Geoeye).

Weekly Report 3 (2014, June 06)

Week 3:

WHAT I GET DONE THIS WEEK:

As a result of a discussion with mentors I have discarded the ossim-orthoigen tool as a reference for my ossim-epipolar app and turned towards ossim-chipper, a newer and clearer one.

I have begun to write the ossim-epipolar app editing the ossimSrtmSupportData class, in order to compute the median height and the standard deviation of SRTM values, parameters that are required for the automatic generation of the quasi-epipolar images.

I have upload the drafted ossim-epipolar app and the related code modified (ossimSrtmSupportData) on the repository (​https://github.com/martidi/OSSIM-GSoC-2014).

WHAT I PLAN ON DOING NEXT WEEK:

To solve the problem on which I am stuck.

To continue working on epipolar images generation

To assess the automatic Tie Points identification.

To begin the implementation of the OpenCV SIFT procedure for automatic TPs generation

To test and control implementation efficacy – discuss results with mentors.

SOMETHING ON WHICH I AM BLOCKED:

I'm trying to use an ASCII DEM file as input for the elevation data, but I have had some issues with it.

Weekly Report 4 (2014, June 13)

Week 4:

WHAT I GET DONE THIS WEEK:

Considering that, as well known the epipolar rectification is a complex topic, I have deeply studied how to implement it (goal of the mid-term). As a result of a discussion with mentors, I have also evaluate alternative approaches for the DSM extraction, such as Vertical Line Locus feature-based type approach, Vertical Line Locus based on a coarse external DSM (such as SRTM or ASTER) and integration of Disparity Map and Non-Disparity Map approaches.

As a result of a discussion with mentors, I have discarded the idea of using Open-CV SIFT procedure for automatic TPs generation since it cannot be included or used as part of a public distribution, and I have chosen another free Open Source detector (Orb-Feature-Detector). Therefore I have wrote a procedure for the automatic TPs detection with Orb-Feature-Detector using the implementation available in the Open-CV library and I have tested it on an Ortho Ready Geo-Eye stereo-pair: I have calculated the x and y parallax errors, and I have seen that these images are basically quasi-epipolar as already projected by provider on a constant ellipsoidical height.

Furthermore I have wrote a procedure for the implementation of the Semi Global Matching algorithm and I have tested it on the above-mentioned images generating the following Disparity Map.

I have upload the code produced on the Git repository (​https://github.com/martidi/OSSIM-GSoC-2014).

WHAT I PLAN ON DOING NEXT WEEK:

To solve the problem on which I am stuck.

To continue working on epipolar images generation and Disparity Map creation.

To test and control implementation efficacy – discuss results with mentors.

SOMETHING ON WHICH I AM BLOCKED:

I am having some issues in the integration between OpenCV algorithms and OSSIM Apps: I have found some compiling problems using some Open-CV basic class (i.e. cv::Mat, cv::imread, etc.). Probably I have not configured rightly the Cmake-List-File.