It is shown how false operator responses due to missing or uncertain data can be significantly reduced or eliminated. It is shown how operators having a higher degree of selectivity and higher tolerance against noise can be constructed using simple combinations of appropriately chosen convolutions. The theory is based on linear operations and is general in that it allows for both data and operators to be scalars, vectors or tensors of higher order. Three new methods are represented: normalized convolution, differential convolution and normalized differential convolution. All three methods are examples of the power of the signal/certainty-philosophy, i.e., the separation of both data and operator into a signal part and a certainty part. Missing data are handled simply by setting the certainty to zero. In the case of uncertain data, an estimate of the certainty must accompany the data. Localization or windowing of operators is done using an applicability function, the operator equivalent to certainty, not by changing the actual operator coefficients. Spatially or temporally limited operators are handled by setting the applicability function to zero outside the window.<<ETX>>
[1]
Hans Knutsson,et al.
Contrast of Structured and Homogenous Representations
,
1983
.
[2]
Hans Knutsson,et al.
Uncertainty and inference in the visual system
,
1988,
IEEE Trans. Syst. Man Cybern..
[3]
Andrew Blake,et al.
Surface Orientation and Time to Contact from Image Divergence and Deformation
,
1992,
ECCV.
[4]
Carl-Fredrik Westin,et al.
Extraction of Local Symmetries using Tensor Field Filtering
,
1992
.
[5]
K. Kanatani.
Structure and motion from optical flow under orthographic projection
,
1986
.
[6]
Randal C. Nelson,et al.
Using Flow Field Divergence For Obstacle Avoidance: Towards Qualitative Vision
,
1988,
[1988 Proceedings] Second International Conference on Computer Vision.
[7]
Hans Knutsson,et al.
The Operational Definition of the Position of Line and Edge
,
1982
.
[8]
C. Westin,et al.
Normalized and differential convolution
,
1993,
Proceedings of IEEE Conference on Computer Vision and Pattern Recognition.
[9]
Hans Knutsson,et al.
Depth and Velocity from Orientation Tensor Fields
,
1993
.