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Invalid ROI

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I'm encountering an error I can't understand. I have built a LabVIEW program using Vision, which will analyse regions of interest drawn on an image and give a histogram for each ROI, as well as a histogram for the average of all the ROIs. When running this on my Desk development PC, this runs fine. When I run this in the Laboratory, on the PC it will run on (which has the appropriate licences) I get an error "Invalid ROI occurs at IMAQ ROI to Rectangle VI" (ROIs are all rectangles and I analyse using the "IMAQ Light Intensity Histogram (Rectangle)" VI, so I must first convert the ROI to a rectangle to do this). Also, no histogram is displayed for the Average ROI, however, they are shown without any problems for the individual ROIs.
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Message 1 of 25
How are you defining the roi? Dynamic? static? If static have you stored it as the default value before migrating?
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Message 2 of 25
Static - and no I'm not... will try that. Thanks 🙂
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Message 3 of 25
Hmm.... I've set a default value before migrating now but it hasn't fixed my problem. Any other ideas?
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Message 4 of 25
Can you attach a screen shot?
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Message 5 of 25
That's quite tricky - I work for a defence organisation. Will try 🙂
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Message 6 of 25
Accepted by topic author dpg1

I personally feel it shouldnt be a problem to show how you are extracting a part of the image. But anyway can you tell me


1. Why you are using a roi to rectangle?

2. If i remember correctly i had suggested you to use "Imaq select rectangle". Are you using it?

3. You have mentioned you want to extract an roi which is static then why not use an imaq extract?

Message 7 of 25
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Message 8 of 25

Off topic: I agree with you - after all, my (bad) LabVIEW code isn't going to be of any benefit to anyone else, but rules are rules and I don't want to risk my job over something like this.


On topic: I'm sorry, I understood (big time). I thought you were talking about the type of data used when you said static/dynamic, which through me off quite majorly. I apologise... the ROIs selected are dynamic (user can select ROIs of his/her choosing).


I did try using the IMAQ Select Rectangle VI but after talking it over with my primary user, he said it would be better if he could just draw on the image display (objects of interest may move slowly while the equipment runs, so being able to make adjustments to ROI on-the-fly is useful), so that's how it currently runs. The user can draw on the image display, and I use property nodes to retrieve the ROI (always in rectangular format - I've removed the other tools). The ROI is then converted into a rectangle to allow use of the IMAQ Light Meter (Rectangle VI).


What do you mean about the "make sure buffernames doesnt clash" - I've not doing anything regarding this. Also can you say what the IMAQ VIs you're using are called?

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Message 9 of 25

Edit: I misunderstood (big time)...

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Message 10 of 25