Corporate Buyers Guide

Vision measuring systems use imaging technology with a CCD camera to inspect objects that are placed on a stage in front of the camera lens. The image is displayed on a computer screen. The system is capable of edge inspection or surface inspection. Most inspections are two dimensional. Limited three dimensional inspection is possible.

The inspection algorithms are becoming simpler to apply as the PC software becomes more user friendly.

Vision measuring systems are primarily used in a laboratory enviroment. With color CCD cameras, inspection by color analysis or differentiation has added another tool to the great variety of inspection tools possible. Unlike with optical comparators, vision measuring system can come with large tables with automatic X and Y axis travel. The combination of camera and scanning table depends on the need of the user, but can produce many complex measurements

Optical comparators perform edge detection using precision optics. Optical lenses have been available for many years and the optical comparator is one of the oldest precision inspection instrument. In an optical comparator, the item to be inspected is placed in a path of light in such a manner that it passes by an edge of the object. The light path may be horizontal or vertical. Horizontal light paths are to inspect small, light weight objects. Vertical light paths are for larger, heavier, objects.

The light is captured by a lens which passes the light beam along magnifying the image and displaying it on a glass screen. When an image is viewed through a magnifying lens, the result is an inverted, turned around, image. This is what is observed in the basic optical comparator. With the use of additional lenses in the path of the light, these problems can be corrected. The most common correction is the turn around image. The result being an upside down image, but with correct side to side view, this makes the interpretation of the image being inspected easier.

Optical comparators come as bench or floor models. The bench models have screen sizes up to 16 inches in diameter. Floor models can have screen sizes up to 70 inches diameter.

These instruments are rugged and lend themselves for many manufacturing environments. However, modern vision technology is replacing the the optical comparator for many applications.