What is a machine vision light source? What are the criteria for selecting it?

Machine vision light source is a part of machine vision imaging, machine vision, the light source mainly plays the following roles: 1. Illuminate the target, improve the brightness formation; Conducive to the effect of image processing. 2. Overcome ambient light interference to ensure image stability; Used as a measuring tool or reference. 3. Through the appropriate light source lighting design, the target information in the image can be separated from the background information, which can greatly reduce the difficulty of segmentation and recognition of image processing algorithms. 4. At the same time, improve the positioning and measurement accuracy of the system, so that the reliability and comprehensive performance of the system are improved.

Three essential conditions for choosing a machine vision light source:

Brightness:

When choosing between two machine vision light sources, the better choice is the brighter one. When the light source is not bright enough, there may be three bad situations.

1. The camera's signal-to-noise ratio is not enough;

2. because the brightness of the light source is not enough;

3. The contrast of the image is not enough, and the possibility of noise on the image is also increased.

Contrast ratio:

Contrast is very important in machine vision systems. The lighting task of machine vision applications is to produce a large contrast between the features that need to be observed and the image features that need to be ignored, so that it is easy to distinguish the features. Contrast is defined as a sufficient amount of gray difference between a feature and its surrounding area. Good lighting should ensure that the features to be detected stand out from the rest of the background.

Stability:

Another way to test a good light source is to see if the light source is sensitive enough to the position of the component. When the light source is placed in a different area of the camera's field of view, the resulting image should not change accordingly. The highly directional light source increases the possibility of specular reflection on the highlighted area, which is not conducive to the subsequent feature extraction.