Study On Key Technique Of Light Source In Machine Vision

Lighting engineering is a key technology in machine vision system.Its main target is to provid proper lighting for objects under inspection and increase contrast of image. A good light source system can greatly enhance resolution while an unsuitable one would cause lots of problems,for example, specular reflection and solarization may hide lots of important information.Firstly,Lighting engineering in the field of machine vision will be particularly discussed in detail. And then to meet the actual need of online measurement,the paper introduces how to build lighting model.Finally,the great mass of this article is focused on research of main idea,hardware and software design of function modules for a 24-phase colour LED dome light source system. Something of this research is interesting in three respects.1. Lighting techniques and spectrum.Both of lighting techniques and spectrum are deeply analyzed here. Angle range is one of the most important facor and lots of experiments had been done to prove the importance of proper angle range. The spectrum is also important in light source system and making the summary proves that if the surface of object is white and does not require the selectivity of color and if the surface of object is color and requires the big contrast of LED color. Moreover, the monochromatic light could avoid chromatic aberration.Also,the effect of polarizing filter and diffusion-board in illumination technology have been studied.The polarizing filter can eliminate glare from a glossy surfaces.The diffusion-board can make light even.2. Lighting Model.The article introduces how to build lighting model by calculation of luminous flux,photometric brightness of both target surface and CCD camera and software simulation .3. The 24-phase colour LED dome light source system,which can realize omniberating and wide angle range lighting which gets good effects in image-measurement application.