"Machine Vision System" What are the system components of machine vision?

1. Lighting

Lighting is an important factor affecting the input of the machine vision system. It directly affects the quality and application effect of the input data of the machine vision light source. Since there is no universal machine vision lighting equipment, the corresponding lighting device must be selected for each specific application instance to achieve the best results. Light sources can be divided into visible light and invisible light. Several commonly used visible light sources are incandescent lamps, fluorescent lamps, mercury lamps and sodium lamps. The disadvantage of visible light is that light energy cannot remain stable. How to keep light energy stable to a certain extent is an urgent problem that needs to be solved in the process of practical application. On the other hand, ambient light may affect the quality of the image, so a protective screen can be used to reduce the impact of ambient light. Lighting systems can be divided into back lighting, forward lighting, structured light and strobe lighting according to their illumination methods. Among them, back-illumination places the object under test between the light source and the camera. Its advantage is that it can obtain high-contrast images. Forward illumination means that the light source and camera are located on the same side of the object being measured, which facilitates installation. Structured light illumination projects gratings or linear light sources onto the object to be measured, and demodulates the three-dimensional information of the object under test based on the distortion they produce. Strobe lighting irradiates high-frequency light pulses onto objects, and camera shooting requires synchronization with the light source.

2. FOV (FieldOfVision) = required resolution * sub-pixel * camera size / PRTM (part measurement tolerance ratio)

lens selection should pay attention to:

• focal length
• target height
• image height
• magnification
• distance from image to target
• center point/node
• distortion.

3. According to different standards, they can be divided into: standard resolution digital cameras and analog cameras.

Different cameras and high-resolution cameras should be selected according to different practical applications: line scan CCD and area array CCD; black and white cameras and color cameras.

4. The visual processor integrates the capture card and processor.

In the past, when computers were slow, visual processors were used to speed up visual processing tasks. Nowadays, because capture cards can quickly transfer images to memory, and computers are much faster, the vision processor is used less frequently.

5. Image capture card

The capture card is only one component of a complete machine vision system, but it plays a very important role. The image grabber directly determines the camera interface: black and white, color, analog, digital, etc.

Typical ones are PCI or AGP compatible capture cards, which can quickly transfer images to computer memory for processing. Some capture cards have built-in multi-way switches. For example, the visual light source can connect 8 different cameras and then tell the capture card to use the information captured by that camera. Visual Light Source Some capture cards have built-in digital inputs that trigger the capture card to capture. When the capture card captures an image, the digital output port triggers the gate.