03-06-2013 03:37 PM
Hi, our team is having trouble understanding the vision processing dashboard example that has been posted in the documents section under "New Examples for 2013". In particular we are having trouble with RGB Lower and Upper values. What are the maximum and minimum number that we can enter into those boxes? Also we are having trouble interpreting what these values do and what the pixel measurements box values is actually telling us. Is there a document explaining how this example is processing images and outputing values? Thanks
03-11-2013 03:46 PM
The maximum and minimum values for the RGB boxes are 255 and 0 respectively. This example uses the IMAQ Color Threshold VI in order to filter an image. You can find the help page on this VI here, http://zone.ni.com/reference/en-XX/help/370281P-01/imaqvision/imaq_colorthreshold/ . That help page should tell you a lot about the VI.
Basically the colors in the image are being designated by the amount of red green and blue in them (like when you mix paint to create different colors). The amount of each primary color present is designated by a number of between 0 and 255. The numbers you are entering on the front panel of the dashboard are the range of colors you are interested in. When you use this filtering an image will appear on the Threshold tab of the dashboard. This image will have any objects inside the color range you designated highlighted in red, and all other objects will have been shifted to black.
As for the values in the particle measurements array these are the center of mass in the X direction, center of mass in the Y direction, and area of the highlighted objects in pixels. You can change the values available in this array by going to the block diagram and editing the input of the IMAQ Particle Analysis VI. All of the code relevant to the vision analysis can be found in Loop 2 on the block diagram.
I hope this helps!