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Computer Vision ... (Published 1992)

Simulated Human Vision..... Ian Overington

Location: Eastbourne. UK
ianoverington@simulatedvision.co.uk ............ www.simulatedvision.co.uk


Appendix 15A. Conditions for growth of perceptual boundaries and for bridging of gaps in the
vicinity of junctions in fragmentary edge maps generated by
VISIVE.

Chapter 16. Differential Texture Analysis.

16.1. INTRODUCTION.

It is generally agreed that the different textural properties of parts of a scene are an important cue to
the underlying scene content. Such properties, which include both local statistical fluctuations and
more global structural elements, may be used for purposes of scene segmentation, recognition and
interpretation. In particular, the local statistical fluctuations are crucially important for camouflage
purposes. In this chapter we shall mainly be concerned with the
sensing of such local statistical
fluctuations and with locating changes in local statistical means which may signal region boundaries.
It specifically
excludes considerations of structural analysis of texture, which has been deeply
studied and reported elsewhere. Also it makes no attempt to
synthesise or simulate texture, topics
which have again been addressed by others.

Most conventional methods of sensing and analysing local texture start with a square matrix
sampled image, frequently coarsely sampled, and seek to quantify the textural properties in terms of
first and second order statistics of individual pixel energy levels. Conversely, over many years our
studies into what are the important factors controlling human thresholds of visual performance (as
discussed in Chapter 2) have led to an acute awareness that the important scene information used by
human vision, both for local
texture perception and for form recognition, is related to fragments of
local maxima of
illumination differences in a hexagonally sampled image, this image being

Continued