Ask the Experts
Published on: 03/29/2019
Last Reply on: 07/01/2019
Category: Vision Software
Hi, i have an application where I need to carry out colour inspection. How to handle such task? What kind of cameras and machine vision algorithms do you recommend? So far I have found out that comparing RGB values is not a good way.
Hello, inspecting color is a wide field and the solution heavily depends on your application requirements. If you have a quality inspection task it can be easy as you can see in our video tutorial: "Easy color inspection with a VeriSens vision sensor" https://www.youtube.com/watch?v=iPZXaNcZnZM&list=PL_OqmiTiIbljP75nM4yXPaLrDrJ_lo7AV&index=12 May be it is a starting point.
Color inspection is a difficult task as it is so lighting dependent. Start with a GREAT really stable White light and Color Balance Target. If you want to verify color quality at the beginning of a run (to make sure your color is perfect), use a spectrophotometer. If you are trying to inspect during production, you would be looking at a color vision system. There is a pretty broad variation in the tools available from one manufacturer to the next. You can usually make RGB systems work, but it can be really confusing. I would look for one that supports HSI (Hue Saturation Intensity) or a variation of this. It makes more sense to human beings that way. For tools Color Histogram or Color meters will generally tell you what color you are looking at in a specific area. Color filters will also help with the tasks looking for variations. Color Blob is great for locating colors (for example sorting Skittles by color). I mostly use Cognex InSight for this. Good Luck!