Three-dimensional object recognition using a quasi-correlator invariant to imaging distances

Natan T Shaked,Joseph Rosen,Gideon Segev

doi:10.1364/oe.16.017148

Abstract

We present a new method for performing electro-optical three-dimensional (3-D) object recognition under incoherent white-light illumination. Perspective projections of the 3-D scene are acquired from multiple points of view and then processed into a single complex two-dimensional modified Fresnel hologram of the scene. This hologram is processed with a single filter which is matched to a single object, so that all identical objects in the scene yield similar correlation peaks in the 3-D space with almost no dependency on the distances of the objects from the acquisition plane. The new method is demonstrated by experiments.

Highlights

Optical three-dimensional (3-D) spatial correlation has been used for numerous applications including 3-D object recognition and target tracking
As shown in this study, this feature can be useful for optical 3-D object recognition, since only a single quasi-correlation operation has to be performed to detect all identical objects in the 3-D scene, no matter whether they are close to or far from the acquisition plane
A set of 200×200 multiple view-point projections (MVPs) was acquired across a transverse range of 12.5 cm × 12.5 cm

Summary

Introduction

Optical three-dimensional (3-D) spatial correlation has been used for numerous applications including 3-D object recognition and target tracking. More recently [2], one of us has suggested to extend the optical correlation from 2-D to 3-D using 3-D optical Fourier transform According to this approach, multiple view-point projections (MVPs) of the 3-D scene, illuminated by. The advantages of this hologram, compared to other MVP holograms, are a direct, efficient, and more accurate digital process, where no redundant calculations, approximations, or assumptions are needed This hologram has a 'side effect' according to which the reconstructed size of all objects of equal size in the 3-D scene is the same regardless of their distances to the acquisition plane. This feature can be useful for optical 3-D object recognition, since only a single quasi-correlation operation has to be performed to detect all identical objects in the 3-D scene, no matter whether they are close to or far from the acquisition plane As shown in this study, this feature can be useful for optical 3-D object recognition, since only a single quasi-correlation operation has to be performed to detect all identical objects in the 3-D scene, no matter whether they are close to or far from the acquisition plane

Description of the method

Experimental results

Conclusions