A major component of an industrial machine vision system

With the development of industrial automation, the application of industrial machine vision system will become more and more extensive. In addition, the rapid development of embedded technologies such as digital image sensors, CMOS and CCD cameras, DSP, FPGA, ARM, image processing and pattern recognition has also brought a huge boost to the development of machine vision inspection. The following Chengdu Xinxiwang will briefly introduce the main components of the industrial machine vision system:

1. Camera and optics

This category usually contains one or more cameras and lenses (optical components) that are used to photograph the object being inspected. Depending on the application, the camera can be based on the following standards: black and white, composite color (Y/C), RGB color, non-standard black and white (variable scanning), step scanning, or line scanning.

2. Lights

Industrial machine vision system lights are used to illuminate parts in order to capture better images from the camera, and the lighting system can be in different shapes, sizes, and brightnesses. Common forms of light are high-frequency fluorescent lamps, LEDs, incandescent lamps, and quartz-halogen fiber optics.

3. Component sensors

This usually comes in the form of light grids or sensors. When the sensor senses the proximity of the part, it gives a trigger signal. When the part is in the correct position, the sensor tells the machine vision system to capture the image.

4. Image grabber

Also known as a video grabber, this widget is usually a card plugged into a PC. The role of this capture card is to connect the camera to the PC. It takes data (analog or digital) from the camera and converts it into information that a PC can process. Industrial machine vision systems can also provide signals that control camera parameters such as trigger, exposure time, shutter speed, and more. There are many forms of frame grabbers, which support different types of cameras and different computer buses.

What to look for when choosing an industrial machine vision system

The performance of an industrial machine vision system is closely related to its components. There are many shortcuts in the selection process, especially in optical imaging, which can greatly reduce the efficiency of the system. Here are a few basic principles that must be kept in mind when selecting components:

Camera The choice of camera is directly related to the needs of the application, and generally considers three points:

a) black and white or color;

b) movement of components / targets;

c) Image resolution.

Most black-and-white cameras are used in inspection applications because black-and-white images provide 90% visual data and are less expensive than color. Color cameras are mainly used in applications where color images need to be analyzed. Depending on whether the part moves during the inspection or not, it is decided whether we choose a standard interlaced or progressive camera. In addition, the resolution of the image must be high enough to provide sufficient data for the inspection task. *The camera must be of good quality and protected from vibration, dust and heat in industrial sites.

Optics and lighting are crucial factors that are often overlooked.

When you use a poor optical component or lighting, even if you use the best machine vision system, it will not even perform as well as a low-capacity system with good optics and proper lighting. The goal of the optics is to produce the best and largest usable area images and to provide the best image resolution. The goal of illumination is to illuminate the key features of the part that needs to be measured or inspected. Typically, the design of a lighting system is determined by the following factors: color, texture, size, shape, reflectivity, and so on.

Although the frame grabber is only one part of a complete machine vision system, it plays a very important role. It directly determines the interface of the camera: black and white, color, analog, digital, etc.

With an analogue input frame grabber, the goal is to convert the image captured by the camera into digital data as unchanged as possible. Using an incorrect frame grabber can result in the wrong data.

Industrial frame grabbers are often used for inspection tasks, but multimedia frame grabbers are not used in this field because they change the image data by means of automatic gain control, edge enhancement and color enhancement circuitry. The goal of frame grabbers using digital input is to convert the digital image data output from the camera into a PC for processing.