ROI descriptor

We want to use the IMAQ read LCD to read the screen on a digital thermometer. We need a ROI descriptor but we do not know what is suitable for that. PLEASE HELP!
Thank you

Hi F.N,
I hope you are well.
One of the easier ways of creating a Region of Interest (ROI) descriptor is to use the IMAQ Construct ROI VI as it allows you to select the ROI convieniently as it saves time creating code to perform the same task.
Essentially a dialog box will pop up allowing you to select the Region that you are interesting in analysing.
More information can be found here:
http://zone.ni.com/reference/en-XX/help/370281P-01/nivisionlvbasics/define_regions_of_interest/
and
http://zone.ni.com/reference/en-XX/help/370281P-01/imaqvision/imaq_constructroi/
Kind Regards,
Aidan H
Applications Engineer
National Instruments UK & Ireland

Similar Messages

How to create a ROI Descriptor using controls?

        Hi All.
        Does anyone know how to create a ROI DESCRIPTOR. Using numeric controls. I have the controls LEFT TOP RIGHT BOTTOM and DEGREES, how to put it in a ROI DESCRIPTOR.    I'm trying to overlay a ROI on and Image Window, The
coordinates I want to show i have it in a .txt file can read if but how to put it in a ROI DESCRIPTOR.
         Thanks
         Reynaldo Lima V.
         Test Software Engineer.
Ing. Reynaldo Lima Villarreal
Ingenieria Electronica (I N G E L)
Reynosa, Tamps. México
Cel: +52 899 160-52-59
Email: [email protected]

Hi. Michael...
I have in mind to draw this VI, I have vision applications and i have to deal with the ROI, the solution is to displace the ROI any way then save the new settings, some times i would be easy to displace the ROI instead of making a new template.   I'm not sure is this is what are you talking about...
Unfortunatly i have more proyects to complete before this VI...
Best Regards..
Reynaldo Lima.
Ing. Reynaldo Lima Villarreal
Ingenieria Electronica (I N G E L)
Reynosa, Tamps. México
Cel: +52 899 160-52-59
Email: [email protected]

Output a ROI Descriptor to a file

What is the best way to export an ROI Descriptor to a file such that it can be read at a later time during a test. I would like to export a number of ROI descriptors to say a txt file, excel file, or some other choice if there is a better option.
Thanks,
Wade
Solved!
Go to Solution.

I did this in a recent project using my own XML utilities
The file looked like:
     <ROI_List>
          <ROI>
               <GlobalRect>
                      <Left>0<\Left>
                      <Right>0<\Right>
                      <Top>0<\Top>
                      <Bottom>0<\Bottom>
              <\GlobalRect>
             <Contours>
                  <Contour>
                        <Type>....
                        <ID>.....
                        <Coordinates> 0, 1, 2.......
                 <\Contour>
             <\Contours>
         <\ROI>
       <\ROI_List>
This worked great for me, I used my own schema but it did require a moderate amount of work.
XML captured the nested nature of the data nicely.
I would start with the ni schema, much less readaable but no work to implement.
There are some free and for pay toolkits but I wrote my own and like it so I have not explored the other options out there.
Paul Falkenstein
Coleman Technologies Inc.
CLA, CPI, AIA-Vision
Labview 4.0- 2013, RT, Vision, FPGA

Progamatically changing ROI colors

I am programmically building multiple image ROI's and then grouping them to display on the image. The ROI Descriptor does not allow specification of the the indiviudal color of the ROI. I can create a "color" property node for each individual descritpor and then define a color for each off the node. However, this is not working. I can not change the color of the group of ROI's let alone each independantly (my goal). I assume that I am not applying the Property Node correctly or in the proper location.
Any advise?

Take a look at the attached. Once a picture loads, add some ROIs to it and then leave the picture. The ROIs themselves are all the same color, but this vi uses an overlay to represent the ROIs when the mouse is not in the image.
Randall Pursley
Attachments:
Colored ROIs.vi ‏47 KB

Break larger ROI into subsections

Hello everyone, I have a question.
Is it possible to take a ROI (perhaps a polyline or freehand drawn one) and subdivide this ROI into rectangular or semi-rectangular rois (with certain size parameters?) I would like to selectively add or subracted certain features in the large ROI before image acquisition.
Thanks,
D.

In LabVIEW, the points of a freehand ROI are actually available in ROI Descriptor::Contours::Coordinates. You could try filtering them manually.
Another option that might work for you is to use "IMAQ ROIToMask 2" to create a binary image, then mask your binary image into the separate rectangular regions you want, and then use "IMAQ LabelToROI" to convert back to an ROI from your masked binary image.
I think the attache LabVIEW 2010 example should explain this.
Kevin C.
Attachments:
ROI Example.vi ‏79 KB

CPU usage for Image acquiring by using Imaq1411

Hello,
Running the IMAQ program makes the CPU usage almost 100%. I tested it out with my own program and the example program you provided. So far I haven't have any clue about this.
I've tried to set the ROI as the help said (Left, Top, Right, Bottom), but failed. I had to set that in the order of Left, Bottom, Right and Top on my program.
With the Snap.vi, I set up the ROI and step x, y. The original image size is 640X480. But I just want to see the center part (160X120) of whole image depending on the Zoom (1:1, 1:2, 1:4). To do that, I programmtically set the ROI and Step (x, y) to be like the followings, which I think makes the same image size (160X120) but a different zoom.
(0, 480, 640,0) and (4, 4) for ZoomX1
(1:1)
(160, 360, 480, 120) and (2, 2) for ZoomX2 (1:2)
(240, 300, 400, 180) and (1, 1) for ZoomX4 (1:4)
Does it make sense?
Thanks, GraceSun"

Hello.
After looking into your question a little more carefully, it seems that you are essentially trying to zoom in on the center of your image. To do this, you should not need to use the Step X, Step Y inputs at all, you should simply have to setup the ROI descriptor to get the selected part of the image. If you would like all images to be the same size, despite the zoom, you should use the horizontal and vertical scaling parameters. See the following KnowledgeBase for more info on these parameters.
Again, I would like to reiterate that the correct order for the ROI should be Left, Top, Right, Bottom. That being said, however, 'If it aint broke, don't fix it
You are definitely on the right track to getting the zooming feature you want down.
Regards,
Colin C.
Applications Engineering
Colin Christofferson
Community Web Marketing
Blog

What is the difference this 2 sample pictures? Use IMAQ Detect Circles function to detect the GREEN button.

Hi All,
Please refer to the attached 2 pictures, they are the similar, just the size is defferent. (pass.PNG, 5478 pass.PNG).
But now i try to use IMAQ Detect Circles to catch the GREEN button. For pass.PNG, it works fine, but for another sample, it is always fail to detect this button.
I also try to change the Curve Parameters and score as input, but still failed. Another way, i also try to use IMAQ find circles function, but the result is worse than IMAQ Detect Circles, so give up.
The code is detect the circles.png, copy it to block diagram enough.
So, what is the root cause? Thanks for help.
Colin
LV7.1/8.2/8.2.1/8.5/8.6/9.0/2010/2013; testing system development
Please Mark the solution as accepted if your problem is solved and donate kudoes
Home--www.colinzhang.net
Solved!
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Attachments:
pass.PNG ‏38 KB
5478 pass.PNG ‏35 KB
detect the circles.png ‏112 KB

Hi colinzhang,
The curve extraction mode if change it to Uniform mode, u can get the result.
-Suggestion, if you want to use the entire image region as ROI no need to get the image size, getting rectangle and converting it to ROI descriptor. (I think this is unnecessary)
-Be careful with color plane extraction, u're using by default which is Red plane. In this example it's fine. but make sure u know which plane u're extracting.
-please find vi saved in 2010 version.
Thanks
uday,
Please Mark the solution as accepted if your problem is solved and help author by clicking on kudoes
Certified LabVIEW Associate Developer (CLAD) Using LV13
Attachments:
Detect_Circles.vi ‏53 KB

Modifying VI - Vision Assistant

I have images that consist of an area of particles and an aera of no particles. I am trying to fit a circle to the edge, between the regions where there are and are not particles. I want to use the find edge tool, and I want to find the pixel where this transistion takes place for every row of pixels. For example, I want to draw a horizontal line that will give me the location of the edge then move down one row and repeat. I have tried using the find circle edge, but since I am trying to fit a circel to an edge that isn't well defined, I need a lot more data points to average over. I figure there is a way to modify the VI to perform the process I described above. Any help would be much appreciated. I have attached the images to give you a better idea of what I'm trying to do.
Attachments:
half circle.JPG ‏554 KB

Hi Windom,
If the find circle edge is not working for you, I would suggest thresholding the image. Then you could use the morphology functions (such as Close, Fill Holes, and Erode) to further manipulate the image to get a stronger edge between the areas of particles and not particles.
You can use a For Loop (initialized to start looking at the top of picture) and have it iterate vertically down the picture with the Edge Detector. You can do that by changing the ROI Descriptor for the line you are detecting edges with, and then you can read the Edge Information out of the VI. These all need to be checked in the "Select Controls" menu, which is found at the bottom right of the Vision Assistant window.
I hope this helps, let me know if you need any further clarification.
Best Regards,
Nathan B
Applications Engineer
National Instruments
Attachments:
SelectROI.JPG ‏12 KB
Edge Info.JPG ‏10 KB
SelectControls.JPG ‏14 KB

Programmatically Reading and Setting PQA MTF Parameters

I'm currently using PQA 1.6 and I'm trying to figure out how to programmatically read and set PQA MTF parameters from a configuration file that I made using the PQA 1.6 GUI. The configuration file that I created is for an MTF test with a ROI already configured.
I went through NI's example of how to modify the provider's settings from a configuration file, I then tried to move on to reading and modifying the existing MTF parameters with no luck. I did see that there is a way to completely override the MTF parameters by using the Provider:Video:MTF method although I would have to then create my own ROI descriptor when I already have one in the configuration file. I simply just want to change one little MTF parameter. So my question is how can I change MTF parameters of an exisiting PQA configuration programmatically.
Below is a snapshot of my VI in case anyone is curious.

Hi DanielID,
After looking into your issue and speaking with some of my colleagues, this is what we have come up with.
It is expected behavior that when you change your resolution, your ROI will be reset. This is because your ROI changes when your resolution changes, and without redefining your ROI, it would yeild unexpected results.
We were, however, able to figure out how to programmatically change the ROI of the configuration file. Take a look at this example that shows how to do this.
Please let me know if you have further questions concerning this example.
Regards,
Leah
National Instruments
Applications Engineer
Attachments:
NI PQA - Scale ROI Position for Different Provider Resolutions.vi ‏35 KB

How to specify an elliptical region to be used in ROIToMask

I'd like to make an specified elliptical descrpitor for IMAQ ROIToMask, but I don't know how.

Ishi,
You can define an Oval for ROItoMask by creating your own ROI Descriptor. Below is the datastructure for an ROI Descriptor. I have provided a description of what needs to be in the ROI Descriptor to create an oval.
Array of Clusters
Array of I32 - Global Rectangle is the minimum rectangle required to contain all of the contours in the ROI.
Contours are each of the individual shapes that define the ROI, as follows:
ID refers to whether the contour is the external or internal edge of an ROI. If the contour is external, all of the area inside it is considered part of the ROI. This VI draws the contours in the order that they are listed in the ROI Descriptor.
Type is the shape type of the contour.
Coordinates is the coordinates that define the contour.
1. I32 Array Global Rectangle is the minimum rectangle required to contain all of the contours in the ROI.
2. Array of Clusters
So, basically you need to define a global rectangle

IMAQ Learn Pattern 2.vi -1074395247 error

Hi,
Development Environment:
LabVIEW 2012 32-bit (12.0f3)
Vision 2012
Description:
Can anyone please shed some light on what ROI Descriptors types are allowed for IMAQ Learn Pattern 2?. Are only certain ROI types allowed for this VI, or can you use any type? I am attempting to create a template image with a mask - The ROI Descriptors type is set to polygon - is this valid or possible?
I get the -1074395247 error: "Invalid template descriptor".
However, just by simply changing the ROI type to Rectangle (and the coordinates to suit), I do not get this error (although this does not correctly mask out the pixels I don't need)
Thanks!
Christopher Farmer
Certified LabVIEW Architect
Certified TestStand Developer
http://wiredinsoftware.com.au
Solved!
Go to Solution.

Hi Chris,
I would consult this KnowledgeBase article which points out why the error is occurring: http://digital.ni.com/public.nsf/allkb/F05924D50AD6472B86256F320075CDBF
Further there should be an example available for this particular VI and its usages with this directory:
LabVIEW\examples\Vision\2. Functions\Pattern Matching\Pattern Matching Example.llb
Thanks!
Matt S.
Industrial Communications Product Support Engineer
National Instruments

Imaq line guage

Hi -
I want to overlay the edge points found using the IMAQ Line Guage VI, very similar to how it is done in the 'Edge Detection Example.vi'.
However, the only outputs for the IMAQ Line Guage VI are distances. I can use the IMAQ Edge Tool 3 to get edge information to overlay, but it is unclear to me that the edge information provided by the IMAQ Edge Tool 3 is consistent with the calculations in IMAQ Line Guage VI. I do need the sub-pixel accuracy.
Can someone let me know how we can do this with IMAQ Line Guage?
As another note, I tried using IMAQ Edge Tool itself but was obtaining some very strange results for distances, which is why I turned to IMAQ Line Guage, which is giving me good results.
Thanks,
Don
Solved!
Go to Solution.
Attachments:
overlay edge points.PNG ‏13 KB

OK. The caliper function finds edge pairs along a specified path in the image. So I tried this but am getting an error that not sure how to handle. Here is my strategy. I am drawing a line on the Vision Image and using the ROI property node to extract ROI descriptor. I use the same edge parameters that I had been using with the Distance fx. Below and attached are the screenshot and VI if you have any suggestions. I am sure we are close. I only want the first and last edge. Distance and coordinates so I can overlay the latter onto the line where edges are detected.
Error -1074395318 occurred at IMAQ Caliper Tool
Possible reason(s):
IMAQ Vision: You supplied an insufficient number of points to perform this operation.
Attachments:
caliper with overlay.vi ‏23 KB

Clever particle filter

Hello,
I am trying to solve a task, where I need to exclude blobs in binary image based on the blob size,
the size treshold changes with the blob position.
Since this is not doable through the standard particle filter, I made mask out of results.
The algorithm is not fast enough + it keeps bad blobs if the later bounding boxes overlap them.
Please suggest some other method.
Bublina
Solved!
Go to Solution.

Hi Bublina!
Your method is a really good start, I would like to add a few ideas to it. First of all, you can add many objects (rectangles, ovals, points, etc.) to a single ROI descriptor, so it's easier to have all removed objects listed in a single ROI, then you can do the masking all at once. You can also fasten execution by using Particle Analysis.vi, which only performs the measurements selected by you, not all of them.
Here's some example code of these changes: (sorry for the picture instead of a snippet, my LV is acting up a bit)
Just replace the code at the red arrow with your decision-making code and it should work.
As you can see it is still quite a simple filter (it masks bounding rectangles), so if you have strangely shaped particles or your particles are too close together, some useful data might be erased. So if you need a more precise approach you could go by labeling your particles (so assigning a different color to each one), then deleting colors from the image based on criteria you specify.
I hope this helps.
Best regards:
Andrew Valko
NI Hungary
Andrew Valko
National Instruments Hungary

Descriptors for multiple ROI's

Hi everyone, I was using "Ctrl" to put multiple ROI's on the image but the descriptor out is always the first one. Can somebody tell me a way to get the descriptors for all the ROI's?
Thanks,
Carol

Hi, the entire VI is too large and complicated, so I just put the relevant parts here; if you need the entire file, I can upload it too.
Basically I tried two methods to get the seperate ROI array and feed it to ROIProfile. Both returned the error.
Attachments:
untitled6.JPG ‏29 KB

How can I select an ROI so that I can remove it?

I need to select a single ROI among other ROI's on an image in order to remove only that selected ROI.

Josey,
Here is a small example that shows how to interactively create and delete contours in an ROI. When a contour is deleted, it's descriptor and index in the ROI are returned.
Regards,
Brent Runnels
Applications Engineer
National Instruments
Attachments:
Select_ROI.llb ‏108 KB

ROI descriptor

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