Color and texture are of considerable importance
for image analysis.
Color as well as texture have been discussed in literature intensively.
But most of the known texture models are based on grey-level images.
This is an inadequate restriction in many real world applications
of computer vision. We are working on color texture models for
micro-textures in natural scenes.
Texture examples
Color Covariance Texture Model
The Color Covariance (CC) texture model is derived from the auto-covariance
model for grey-level images. This texture model is defined for color images
with three color planes, e.g. RGB-images. Interactive relations between
different color planes are calculated by a second order statistic.
Formula
Color Texture Synthesis
The synthesis of color texture is examined in order to find an
optimal set of color texture parameters describing natural color
textures. If a good re-synthesis of color textures is possible then
an adequate parameter set is found.
The texture synthesis in the CC model follows an
evolutionary strategy.
First a random color texture is generated with the same color
histogram as the original texture. In several iterations all
pixels of the image are exchanged in their position to make the
synthesized texture more similar to the original.
The significance of the color texture parameters have been examined
in order to find a minimal set of color texture parameters.
The number of the CC parameters used for synthesis and the
quantity of the color histograms used for initialization have
been reduced in many experiments.
Examples of color texture synthesis
Color Texture Classification
Also classification is used in order to find a reduced parameter set
of the CC texture model. Therefore a large set of images was built showing
the bark of 408 different trees of six species. The color texture of
these images are classified by a K-Nearest-Neighbour Classifier.
In various classification experiments a new set of color texture
parameters was proofed to work well. These parameters are related to
the human perception of texture. For further reduction of the
dimension of the feature space the Principal Component Analysis from
statistics is applied among other methods.