The Role of Light Sources in Machine Vision

A complete machine vision inspection system includes an image collection part and an image analysis part, and the image collection part is mainly undertaken by industrial cameras, industrial lenses and machine vision light sources.

Ⅰ. What is the role of light sources in machine vision?

Illuminate the object, increase the height, form an imaging effect that is beneficial to image processing, reduce the complexity of the system and the requirements for image processing algorithms, defeat ambient light interference, ensure image stability, and improve system accuracy and power.

Through proper light source lighting planning, the information in the image and the scene information can be optimally separated, which not only greatly reduces the algorithm difficulty of image processing, but also improves the accuracy and reliability of the system.

But it's so small that there isn't a universal machine vision lighting system right now. Different inspection requirements can be handled, so for each specific case, it is necessary to plan adapted lighting equipment to achieve the best effect. Improper lighting can cause many problems. Machine vision light sources are so important, they are often overlooked by many people.

Ⅱ. The light source of machine vision chooses LED

Now the light source of machine vision system mainly uses LED (light emitting diode), which is widely used in the industry due to its high degree of freedom of shape, long service life, fast response speed, good monochromaticity, various colors, and high cost performance.

1. Shape freedom. An LED light source is composed of many individual LEDs. Therefore, compared with other light sources, it can be made into more shapes, and it is easier to plan the shape and size of the light source according to the user's condition.

2. Long service life. In order for the image processing unit to obtain accurate and reproducible measurement results, the lighting machine vision system must ensure that a stable image input can be provided for a reasonably long period of time. The brightness of the LED light source decreases after 10.0 to 30,000 hours of continuous operation, but it is far better than other types of light sources. In addition, the continuous operation of the control system can suppress the heating of the luminous tube, and the service life will be doubled.

3. Fast response. The response time of the LED light-emitting tube is very short. The real meaning of the response time is to ensure the operation switching between multiple light sources or between different areas of a light source. When a dedicated controller is used to supply power to the LED light source, the time to reach the maximum illumination is less than 10s.

4. Various colors. Except for the shape of the light source. Another aspect of getting a stable image input is choosing the color of the light source. Even light sources of the same shape can produce very different images due to differences in color. In fact, how to use the technical characteristics of the color of the light source to obtain the image with the best contrast has always been the main direction of the development of the light source.