In machine vision system, it is very important to obtain a high quality and tractable image. The system is successful, first of all to ensure that the image quality is good, features obvious. Most of the failures of a machine vision project are caused by poor image quality and inconspicuous features. To ensure a good image, you must choose a suitable light source. The following editor of ADTECH machine vision system manufacturer mainly comes to introduce the basic elements of light source selection in machine vision system, the specific content is as follows:
Contrast: Contrast is very important for machine vision. The most important task of illumination for machine vision applications is to maximize the contrast between the features that need to be observed and the features that need to be ignored, so as to facilitate feature discrimination. 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.
Brightness: When choosing between two light sources, the best option is to choose the brighter one. When the light source is not bright enough, there are three bad things that can happen. First, the camera's signal-to-noise ratio is not enough. Because the brightness of the light source is not enough, the contrast of the image is inevitably not enough, and the possibility of noise on the image also increases immediately. Secondly, the brightness of the light source is not enough, it is necessary to increase the aperture, thereby reducing the depth of field. In addition, when the brightness of the light source is not enough, random light such as natural light will have the greatest impact on the system.
Robustness: Another way to test a good light source is to see if the light source is minimally sensitive to the position of the component. When the light source is placed in different areas of the camera's field of view or at different angles, the resulting image should not change accordingly. The highly directional light source increases the possibility of specular reflection in the highlighted area, which is not conducive to the later feature extraction.
A good light source should be able to make the features you are looking for obvious. In addition to the camera being able to photograph the parts, a good light source should be able to produce maximum contrast, be bright enough, and be insensitive to changes in the position of the parts. When the light source is chosen, the rest of the work is much easier. The specific light source selection method also depends on the practical experience of the experiment.