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IMAGE UNDERSTANDING AND AESTHETIC
EVALUATION
Z. Les
(extract from a book that is prepared
for publication in the QJF Press)
In traditional aesthetic,
the interpretation of works of art in terms of their “form” or “structure”
is often distinguished from the interpretation of work in terms of their
“content” or “association”. For the picture, a “form” corresponds more or
less to how a work of art is “composed”. The composition of the picture
treats a work of art as a coherent whole that can be divided into several
parts, each bearing a relation to the whole. The interpretation of a work
of art in terms of its form considers the properties of this whole, its
parts, and their relations. These properties in a painting include colour, shape, texture and a rule of composition of
those elements on the picture’s plane.
Image understanding refers to a
computational approach to image interpretation. It stresses functional
aspects of the information conveyed by an image, and can be expressed as
follows: when an object (in the image) is discovered an action should be
undertaken. Pictures which are created for artistic proposes cannot be
regarded within this functional framework. However, the possibility exists
of applying a similar image-understanding approach to this class of
pictures in order to find a methodology that will allow for aesthetic
evaluation of the pictures. The image-understanding approach has been used
to develop a method of aesthetic evaluation of a class of pictures
(abstract paintings). This method has been applied to a particular class of
abstract paintings, the Mondrian class, in order
to find composition rules of works of art and to evaluate pictures. To
evaluate pictures from the Mondrian class a
neural network method was used.
General description of the method
The method of aesthetic
evaluation of a picture (an abstract painting), which is elaborated for the
purpose of the present research, is based on an image understanding
framework.
The proposed method of aesthetic
evaluation of the picture consists of two main stages:
1. To establish a generic class
of pictures (which is established on the basis of the characteristic
properties) and to find descriptors which can be used for aesthetic
evaluation of the picture (within the same generic class).
2. For a given generic class,
to find a form of an aesthetic evaluation function used for aesthetic
evaluation of the picture in the sense that the picture can be recognised as a work of art or not a work of art.
Picture
In the present research the
term “picture” refers to an abstract painting. The term “abstract painting”
is often used to describe a set of works of art (paintings) which consist
of geometrical figures, nonregular shapes or
texture. Among pictures (abstract painting) there are pictures which are
called works of art and pictures which are not works of art (ordinary
pictures). It is assumed that a work of art is a picture (abstract
painting) which was created until now, and can be found in galleries or art
literature. On the other hand, there are many pictures (abstract paintings)
which are created by painters but which are not recognised
as works of art. These pictures are termed ordinary pictures. It is assumed
that pictures which are works of art were distinguished from a large number
of pictures by critics based on aesthetic criterion (in the present
research problems of new aesthetic or anti-aesthetic are not discussed).
Shape
In art shape is often described
in terms of boundary curve or as a region of a given colour.
In an “abstract” painting, shape is often described as a circle, ellipse,
square or irregular shape. In image understanding, shape analysis provides
a means of symbolic description of the image. Three-stage processes are
used in shape analysis: shape detection, shape description and
representation, and shape classification. This method, which enables shape
description as a set of primitives and a set of rules, can be used for
aesthetic evaluation of the picture. The rules which are thus obtained can
be used to discover regularities among the shapes of a work of art.
Texture
Texture can be viewed as a
global pattern arising from the repetition, either deterministically, or
randomly, of local patterns and can be defined as a repetition of the basic
texture elements called texels. In painting
texture relates to the surface of the picture and is a result of applying
different techniques to evoke an artistic effect. Texture elements are
arranged according to placement rules which can be random or regular. For
example, Pollock’s picture, which was obtained by dripping a liquid paint
from a can or spattering it in long arabesques with a stick, possesses a
texture which can be described as a “random” placement of texture elements.
Some picture
regions (picture elements) possess a characteristic texture which can be
analyzed by using methods of texture analysis. There are many methods of
texture analysis, such as autocorrelation function method, texture
transforms method, congruence matrix or co-occurrence matrix which can be
used to obtain a set of picture descriptors.
Image processing
The visual attributes of
picture objects such as shape and texture can be characterized by a set of
descriptors obtained by applying image processing methods. A method of
aesthetic evaluation of the picture which was established for the purpose
of the present research allows evaluation of a large class of pictures.
Depending on the class selected (e.g. Kandinsky
or Mondrian class), the different image
processing methods can be applied to find a set of picture descriptors.
Edge detection, segmentation and filtering are some of the methods that are
used. on many of the pictures.
Examples of the image processing method applied to
extract useful information from image are shown below.
 
Examples of the extracting shape from
the ordinary picture by applying image processing method
  
Examples of extracting shape and
structural information from the picture (work of art) by applying image
processing method
   
Examples of extracting shape and
structural information from the picture (work of art) by applying image processing method
    
Examples of extracting shape and
structural information from the picture (work of art) by applying image
processing method
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