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Topic Id:

ID topic:	584
Partner Email:	dtdim@iinf.bas.bg
Project Title:	2D Calibration of Images from a Digital Photo Camera
Abstract:	The application of digital cameras recently competes very successfully with conventional 2D-scanners, even in the cases of scanning/photographing of bidimensional objects, for example, paper documents. In addition, cameras are irreplaceable when the object is of a very large size, if it is placed at a position, unsuitable for classical scanning, if it is definitely three-dimensional, and so on. Similar examples are plentiful in the systems for machine vision, but the application considered is connected with the so called system “Bulgarian State Emblem”, in which a digital camera is used besides a scanner for the input of relief replicas of the state emblem. The cameras, like the scanners, cause different types of distortions – colour, geometric, etc., most of which are technologically ignored/compensated for. Yet, there appears a specific geometric distortion in cameras, caused by the slope of the camera with respect to the plane of the object photographed. For example, if you take a snap of a square at an angle, different from 90 degrees, the image obtained (its central projection) will not be a square. In order to use the image in measuring systems, it is necessary to evaluate the parameters of the projection and to restore the image, as if photographed by a vertically positioned camera. A typical solution of this problem in computer photometry, is the use of additional information about 6 reference points. Our purpose is to define the solution using only 4 reference points (defined, for example, by a reference square). The latter condition complicates the solution, but offers considerable facilities to the user. Purpose of the diploma work offered: To develop an algorithm and a software program restoring a 2D image (photographed at a slope), with additional input data – the actual distances between 4 reference points in the image. The program is to be tested on digital images of the State emblem, photographed by a camera. The problem solution will require thorough work in the following directions: (1) Iterative methods for solving nonlinear systems of equations; (2) Geometric transformations of 2D images; (3) Programming in the environments of MatLab and C/C++. The development will include the following parts: - A module for estimation of the parameters of a projection of a 2D image on the photographic plane. A square is marked (drawn) a’priori on the image; - A module for image restoration with respect to the parameters estimated in (1); - A test system for demonstration of the developed modules (1) and (2). Input – actual images taken from the practice of “State emblem” system, in a BMP or JPG format. Recommended environment for the software experiments – Borland C/C++ Builder. Preliminary set up and test of the algorithms is recommended in MatLab environment.
Advisor:	Assoc. Prof. Dr Dimo T. Dimov
Link:
Degree:	Master
Keywords:
Computer graphic
Image processing