Measuring the distance of an object

This was a small demo that I did in Processing 1.0 to test stereo vision.

I took two pictures with a webcam. The second picture was taken 7 cm  (b) to the left of the first. In this demo, to measure the distance of a point I pick the same point in each picture. The distance is measured using triangulation. There is a linear relation between the displacement (H) in pixels ( green line in the door locker ), and the distance (Z).

H=b/Z

This only happens when the two images are taken by two cameras that are side by side on the some plane.

OpenCV the Computer Vision Library

Great library, but it is very hard to make it work on Visual Studio 2009. There is no default .lib for VS so you have to make them yourself.

These are the instructions from the file:

OpenCV-2.0.0a-win32.Readme.Please.txt

1. Download CMake from http://www.cmake.org/cmake/resources/software.html
   and install it.

2. Run CMake GUI tool and configure OpenCV there:
   2.1. select C:\OpenCV2.0 (or the installation directory you chose)
        as the source directory;
   2.2. choose some other directory name for the generated project files, e.g.
        C:\OpenCV2.0\vs2008, or D:\Work\OpenCV_MinGW etc.
   2.3. press Configure button, select your preferrable build environment
   2.4. adjust any options at your choice
   2.5. press Configure again, then press Generate.
3a. In the case of Visual Studio or any other IDE, open the generated
   solution/workspace/project ..., e.g. C:\OpenCV2.0\vs2008\OpenCV.sln,
   build it in Release and Debug configurations

3b. In the case of command-line Makefiles, enter the destination directory
    and type "make" (or "nmake" etc.)
4. Add the output directories to the system path, e.g.:
   C:\OpenCV2.0\vs2008\bin\Debug;C:\OpenCV2.0\vs2008\bin\Release:%PATH%
   It is safe to add both directories, since the Debug
   OpenCV DLLs have the "d" suffix, which the Release DLLs do not have.
5. Optionally, add C:\OpenCV2.0\include\opencv to the list of
   include directories in your IDE settings,
   and the output library directories
   (e.g. C:\OpenCV2.0\vs2008\lib\{Debug,Release})
   to the list of library paths.

One afternoon was lost with this, It would just be better if they gave all the compiled stuff from the beggining…

Tema da tese definido

“Building interactive spatial and temporal models
using multimodal data”

 

Abstract

The construction of virtual world models is an important step in several applications from simulations to virtual reality. These threedimensional worlds are usually constructed oine from scratch or using large datasets of data extracted from satellites. Once they are constructed they are usually static or hard to alter automatically. What is proposed in this thesis is a  method to create methods that would take advantage of several types of low-cost sensors and computer vision to quickly create and update virtual models. These virtual models will have live feeds from the sensors and from images and videos. The resulting model can be consulted in terms of space and time, turning on and o several layers of information. These models can  then be used in several scenarios such as retrieving information from a physical space, creating simulations or creating augmented reality scenes. One of the main ideas proposed is the fact that changes in the virtual model can be reflected back to the images and videos that helped in its construction. This reconstruction of reality can have several applications to visualize the results of environmental simulations such as pollution or disaster simulations, showing the a ected areas in real life images. Additionally it can be useful to superimpose virtual objects to be used in augmented reality, turning the room where the user is into a completely di erent scenario. The construction of the models involves the study of several image processing algorithms and techniques. Additionally, to support the fast creation, visualization and interaction with the models several tools will have to be developed. The interaction should explore new paradigms di erent from the mouse and keyboard. Essentially it should take advantage of the computer vision knowledge learnt in the construction of the models. This document addresses the problems involved in this area, presents related work, preliminary solutions and a work plan for the thesis.