Issue finding edges on square feature

[pbuerki]

Hi,

I am making my first baby steps with NI Vision and the NI Vision Assistant, so please forgive me, if this is a basic question.

I have created a process, where I load an image with a square feature. I am trying to detect all four edges and determining the slope. (I plan to use this information in an autofocus vi as feedback for operating using an xyz stage.) When I convert the Vision Assistant script into a LabVIEW vi, the vi only returns edge parameters for edges three and four, while edges 1 and 2 produce an empty array. What is the reason for this behavior and how can I get the vi to return all four edges? Thanks for your help.

Peter

[Burrito · Accepted solution]

Hi pbuerki,

I noticed in your Vision Assistant program that your first 2 edge detect steps do not actually find any edges. This may be because you need to specify where in the image you want to look for edges. You can do this by editing your edge detect step, clicking on the image and creating a line on which to look for a change in the value of neighboring pixels. 

Also, here is a tutorial for Vision Assistant that might be helpful for you in the future.

[pbuerki]

Hello Burrito,

Thank you for your reply. I ran the script again and redefined the ROIs. And now it is working. 🙂 Thank you also for the link to the tutorial.

Regards,

Peter