A few questions regarding the use of Vision

[kirkland4]

I am trying to use NI vision in conjunction with LABview. In LABview my tool palette for "Vision" is empty though, I have installed labview 7 express, as well as NI Vision assistant 7.1


With vision I am trying to measure the length of a feature on a surface, which will be inputted by a camera. Other than pattern matching, what other techniques may be used to determine the measurement points?

thank you.

[Scott_R]

Hello,

When you installed the NI Vision Development Module, did you select to install support for LabVIEW?  To get the Vision palette to appear in LabVIEW, try the steps listed in the following KnowledgeBase:

Why are my Motion or Vision VIs not in the LabVIEW Functions Palette?

http://digital.ni.com/public.nsf/websearch/3D4BC54D0DEE0EF286256C92005B5F5D?OpenDocument

I would suggest performing an edge detection or other method to determine the end points of the object that you are trying to measure.  From there, I would use a caliper function to measure the distance between the two points that you have obtained.

Regards,

Scott R.

Applications Engineer

National Instruments

[kirkland4]

Thank you Scott!

I did not install Labview support so the VIs werent appearing, this was fixed, thanks!

As for the edge detection, My only problem is that the feature does not have a clearly defined edge (it is gradual), so the edge detector does not work very well..

I am trying to play with pattern matching, though that again does not always work due to the fact that my images are not homogenous...

thanks.

[AnalogKid2DigitalMan]

Can you do anything with lighting to improve the sharpness of the edge of interest?

[kirkland4]

AnalogKid2DigitalMan,

Yes I can. Unfortunately the lighting setup on this experiment was not done with the best foresight. so there are parts of the image which have a color value similar to the area of the feature.

I have been trying to utilize filters and thresholds, unfortunately the feature and parts of the background are filtered hand in hand.

Perhaps there is a way I may isolate the ROI based not only of color but also shape, texture, etc.

thanks again.

[chilly_charly]

Post an example image. May be somebody will bring in some idea for an efficient processing !..

[kirkland4]

Ill do that as soon as I get approval...thanks!