Vision Assistant Express VI Output Signal

[DerbyTom]

Hello.

I am using LabVIEW to try and detect the presents of a part with a USB camera. I have set up a match pattern inspection in Vision Assistant and want to output a Boolean signal if a pattern is matched.

Thank you

[DerbyTom]

I'm not sure how it works but I would like to put it into a case structure, unbundle some of the match pattern array's and say true if dictated.

[J_Oneill]

Hi Tom,

There are many ways you can do this with the Vision Assistant Express VI.

It is worth noting that you do not necessarily have to have a Boolean wired to a case structure, you can also use numeric data types.

You can use the “Number of Matches” that the Express VI returns, wire this into a case structure and add cases for different numeric values. You could also index the array from “Matches” then unbundle it and in the same way, wire one of the attributes to a case structure.

I hope this helps,

James O’Neill – Applications Engineer – National Instruments 

[DerbyTom]

Thank you for the reply it was really helpful! I have one more question which is still relating to the Vision Assistant Express VI. I'm using the 

Edge detection, which has a threshold value to output a numeric 1 or 0 depending is a part passes the region of interest. I’m using a numeric compare function to send a Boolean indicator high or low. I want to add to this by counting the number of parts that pass through the area of interest but I’m having a difficult time working out how to do this.

I would like to set a variable that will increment every time the indicator is pulsed but I haven’t been able to find a way to do this. I’ve also looked into the possibility of using a shift register.

Thanks

[DerbyTom]

Managed to solve the issue. Basically using a shift register with a comparison function where by the Boolean expression is compared with the last expression used in the shift register. This is then fed into a case structure for a raising edge counter.

Thank you for the input!