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other higher-level constructions. |
other higher-level constructions. |
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These higher levels are not yet thoroughly understood; |
These higher levels are not yet thoroughly understood; |
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theories of structural object perception |
theories of structural object perception |
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(see e.g. Biederman\cite{biederman87}) |
(see, e.g., Biederman\cite{biederman87}) |
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propose certain primitive shapes whose |
assume certain primitive shapes whose |
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structure facilitates recognition. |
structure facilitates recognition. |
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We use a rough, qualitative model of visual perception |
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(see Fig.~\ref{fig-perceptual}). |
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\begin{figure} |
\begin{figure} |
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\centering |
\centering |
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%\fbox{\vbox{\vskip 3in}} |
%\fbox{\vbox{\vskip 3in}} |
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the intensities of different features, |
the intensities of different features, |
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such as local and global shapes and colors, |
such as local and global shapes and colors, |
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combine to form an abstract \emph{feature vector}, |
combine to form an abstract \emph{feature vector}, |
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as used in neural computation. |
as used in neural computation |
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(see Fig.~\ref{fig-perceptual}). |
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This feature vector is then used as an input to the |
This feature vector is then used as an input to the |
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networks which linearly compute which concept the particular |
networks which linearly compute which concept the particular |
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input corresponds to, in a perceptron-like |
input corresponds to, in a perceptron-like |
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fashion\cite{widrow60adaptive,rosenblatt62neurodynamics}. |
fashion\cite{widrow60adaptive,rosenblatt62neurodynamics}. |
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From this picture, we can formulate the following points: |
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From this |
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rough, qualitative model of visual perception |
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we can formulate the following points: |
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To be distinguishable, \label{secfeaturevec} |
To be distinguishable, \label{secfeaturevec} |
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\begin{itemize} |
\begin{itemize} |
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\item A feature vector for a given texture should be always the |
\item A feature vector for a given texture should be always the |