Scale-Spaces and Edge Detection

Lenna´s scale-space samples


Master's Thesis Summary:

Scale-Spaces provide a way of organizing and analyzing all scales of an object in a single structure.

The linear scale-space of an image is the solution of the diffusion equation (with the image as the initial condition). This scale-space is built through applying the gaussian filter with increasing variances to the image. As a result, a three-dimensional structure of blurry images is obtained.

In this thesis, the main theoretical properties of continuous and discrete linear scale-spaces are described, as well as several types of discrete scale-spaces, such as sampled gaussian, Poisson, recursive gaussian, crossed convolution, splines and infinitesimal generator. Also, specific details of the discrete scale-spaces implementation are examined.

The thesis continues analyzing the methods of edge detection - including its implementation - starting from an image and starting from the multi-scale analysis of an image.

download thesis (PDF - 1.8MB)


The implementations of scale-spaces and edge detection were coded in ANSI-C.

download programs - scaspa.tar.gz

To install and compile, type on the command line:

>gunzip spasca.tar.gz
>tar xvf spasca.tar
>cd spasca
:spasca> make all

In case of any doubts, suggestions or critics, please write to mayrink@impa.br