The lighting system is one of the most critical components of a machine vision system. The light source directly affects image quality, and consequently, system performance. Its importance cannot be overstated. Good lighting design enables us to obtain a good image, thereby improving the overall system resolution and simplifying software calculations, while unsuitable lighting can cause numerous problems.
The core of a machine vision system is image acquisition and processing. All information originates from images, and the quality of the images themselves is extremely critical to the entire vision system. Light source is a crucial factor affecting the image quality of a machine vision system, as it directly impacts the quality of the input data and at least 30% of the application's effectiveness.
Appropriate light source design can optimize the separation of target information from background information in an image, significantly reducing the algorithmic complexity of image processing while improving system accuracy and reliability. Conversely, improper light source design can lead to inefficient image processing algorithm design and imaging system design. Currently, there is no universal machine vision lighting device; therefore, suitable lighting devices must be designed for each specific case to achieve optimal results. Thus, the success or failure of the light source and optical system design is a primary factor determining the success or failure of the system. In machine vision systems, the role of the light source includes at least the following:
1) Illuminate the target and increase its brightness;
2) To create an imaging effect that is most conducive to image processing;
3) Overcome ambient light interference and ensure image stability;
4) Used as a tool or reference for measurement;
An ideal light source should be bright, uniform, and stable. There are three main types of light sources used in visual systems: high-frequency fluorescent lamps, fiber optic halogen lamps, and LED light sources. Currently, LED light sources are the most commonly used, and they have the following main characteristics:
*It can be made into various shapes, sizes, and various irradiation angles;
*It can be made in various colors as needed, and the brightness can be adjusted at any time;
*With the heat dissipation device, heat dissipation is better and the brightness is more stable;
Long service life;
* It has a fast response time and can reach maximum brightness in 10 microseconds or less;
*The power supply has an external trigger, can be controlled by a computer, has a fast start-up speed, and can be used as a strobe light;
LEDs with low operating costs and long lifespans will have a greater advantage in terms of overall cost and performance;
*Custom designs can be made according to customer needs.
