Image life tunnel scanner inspection system using extended depth of field technology

Abstract

An image lift tunnel scanner uses extended depth of field cameras in order to view objects of various shapes and sizes on a conveyor system. The image lift tunnel scanner operates by passing a package first through a dimensioning device, such light curtain that determines the package's height, width, length, orientation and position on the conveyor belt. A bottom scan camera takes a fixed focus image and requires only a trigger and length information from the light curtain. The length information determines the duration of the scan after the camera receives the trigger signal. A top scan camera also requires a trigger and the length information along with the height information so that it can set its focus. Each of two side cameras also receives trigger and length information. If the package is registered on the conveyor belt, the only additional information required is the package width and the package position on the conveyor belt so that the start and stop of the image scan can be calculated. A first side camera scans the front of the package as the package approaches the camera. The first side camera views the front side of the package at a 45 degree angle. After sweeping the front of the package, the scan line of the first side camera continues sweeping along the side of the package, again at a 45 degree angle, but shifted 90 degrees relative to the angle at which the front side of the package was scanned. A second camera views the back and the other side of the package.