Abstract

The human visual system exhibits two properties that may be useful in other pattern-recognition systems: (1) images do not change their shape with changes in image size and (2) resolution declines rapidly with distance from the center of fixation. We show here that, in general, shape invariance requires inhomogeneous resolution over image space in a manner similar to that of the human visual system. Thus shape-invariant systems must process less information when compared with uniform-resolution systems. Although shape-invariant systems can be rotationally invariant, they cannot, in general, be translationally invariant. The properties of shape-invariant systems are explored in the spatial-frequency domain using a modified Fourier transform called a scaled transform. The features of scaled transforms are discussed and their behavior illustrated in the image domain by using them to filter various images, including the dot, the line, and the edge. It is shown that the filtered profile of an edge is preserved when it passes through the origin of a scaled transform. This result suggests that scaled transforms may be useful in edge-detection algorithms.

© 1984 Optical Society of America

Full Article  |  PDF Article
OSA Recommended Articles
Image invariance with changes in size: the role of peripheral contrast thresholds

Eli Peli, Jian Yang, and Robert B. Goldstein
J. Opt. Soc. Am. A 8(11) 1762-1774 (1991)

Geometrically robust image watermarking by sector-shaped partitioning of geometric-invariant regions

Huawei Tian, Yao Zhao, Rongrong Ni, and Gang Cao
Opt. Express 17(24) 21819-21819 (2009)

Position-invariant, rotation-invariant, and scale-invariant process for binary image recognition

J. Levkovitz, E. Oron, and M. Tur
Appl. Opt. 36(14) 3035-3042 (1997)

References

You do not have subscription access to this journal. Citation lists with outbound citation links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Cited By

You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Figures (18)

You do not have subscription access to this journal. Figure files are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Tables (2)

You do not have subscription access to this journal. Article tables are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Equations (62)

You do not have subscription access to this journal. Equations are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Metrics

You do not have subscription access to this journal. Article level metrics are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription