Machine vision is the use of computer vision applied to manufacturing and industrial automation. Machine vision systems are an electronic replacement for less-than-perfect human inspectors. These systems perform precise visual inspections during the manufacturing process to validate the accuracy and quality of work performed.
These systems use smart digital cameras and specialized image processing software to perform electronic inspections.
Common applications include the validation of the presence and correct placement of parts, the verification that measurements meet defined tolerances, and the capture of data elements such as serial numbers or lot IDs in manufactured items including electronic parts, food, automobiles, and pharmaceuticals.
Each application is unique so specific components are configured for each solution. System components fall into the following general categories:
Cameras and Optics – One or more digital/analog cameras and optics which take a picture of the part(s) being inspected. These cameras can be monochrome, composite color, RGB color, variable-scan, progressive-scan, or line-scan depending upon the specific application requirement.
Lighting – The right lighting is key for optimal illumination of the part so that the camera can capture the best possible image. Types of lighting include high-frequency fluorescent, LED, incandescent, and quartz-halogen fiber-optic.
Presence Sensor – This is a device which alerts the system when it senses that the part to be inspected is approaching. This allows the machine vision system to acquire an image when a part is in the correct position.
Computer Processor – The computer processor is typically a high-end PC or digital signal processor. A ruggedized computer is often required in manufacturing environments due to dirt, vibration and temperature extremes.
Frame Grabber – A frame grabber interfaces the camera(s) to the computer processor. It takes the digital or analog image data provided by the camera and converts it into information for use by the computer. Frame grabbers come in many configurations supporting different cameras and computer processor types.
Machine Vision Software – Software comes in many different forms. It is used for creating and executing programs, processing acquired image data, and making inspection decisions such as pass/fail.
Network connection and Digital I/O – After the machine vision system completes its inspection of a part, the inspection results must be communicated to the system controlling the manufacturing process. Typically, a network card or digital I/O interface board is used to accomplish this.