# Accession Number:

## ADA109032

# Title:

## Rotationally Symmetric Operators for Surface Interpolation

# Descriptive Note:

## Memorandum rept.

# Corporate Author:

## MASSACHUSETTS INST OF TECH CAMBRIDGE ARTIFICIAL INTELLIGENCE LAB

# Personal Author(s):

# Report Date:

## 1981-11-01

# Pagination or Media Count:

## 38.0

# Abstract:

The use of rotationally symmetric operators in vision is reviewed and conditions for rotational symmetry are derived for linear and quadratic forms in the first and second partial directional derivatives of a function fx, y. Surface interpolation is considered to be the process of computing the most conservative solution consistent with boundary conditions. The most conservative solution is modelled using the calculus of variations to find the minimum function that satisfies a given performance index. To guarantee the existence of a minimum function. Grimson has recently suggested that the performance index should be a semi-norm. It is shown that all quadratic forms in the second partial derivatives of the surface satisfy this criterion. The seminorms that are, in addition, rotationally symmetric form a vector space whose basis is the square Laplacian and the quadratic variation. Whereas both seminorms give rise to the same Euler condition in the interior, the quadratic variation offers the tighter constraint at the boundary and is to be preferred for surface interpolation. Author

# Descriptors:

# Subject Categories:

- Theoretical Mathematics