Real time pattern recognition

[Joanna03]

 I'm trying to build a pattern recognition system, so that I can detect in real time "STOP" traffic signs. I've build a template and a script using Vision Assistant, an then I used the "Export to VI" option. I've been trying to modify the generated VI, to add the webcam part. I can't figure out what's wrong, as the program captures video, but the pattern recognition part doesn't behave as I want,it just applies some image filters and displays the first captured image. I'm a begginer in LabVIEW, please help me figuring out what's wrong. It should show the captured video, marking the pattern if one is found. Thanks

[NateBraska]

Hi Joanna,

Do you have any sample images that I could use for testing?

Are you able to get it to detect the stop signs with just the original Vision Assistant express VI? As in, is the problem the detecting the sign, or is it the transition from the Vision Assistant to VI's?

Also, did you mean to have a forward slash ( / ) versus a back slash ( \ ) in your image name? I would suggest that you create that image outside the while loop and dispose of it when the program finishes, this way you are not recreating it each loop iteration.

If you could provide me with some of your test images, including the match you are looking for and anything else I might need to run the program, I would happy to help you continue troubleshooting this issue.

Best Regards,

Nathan B

Applications Engineer

National Instruments

[Joanna03]

  Hi Nathan,

   Thanks for the reply. I've managed to solve some of the issues. I've given up trying to do the geometric matching real time. I just want to do this against a couple of local images. My big problem right now is that I can't manage to display the overlay over the initial image, as this gets distorted in the process (applying the color threshold, the equalize feature and so on). I guess I don't understand correctly how the matching algorithms work. I would greatly appreciate if you could point me in the right direction...basically, I want to display a rectangle overlay over the initial image. I have a couple of questions from there on, but I want this solved first. I've attached my latest VI, the VisionAssistant script for detecting the signs and an image I use to test. Thank you

[NateBraska]

Hi Joanna,

No problem. I also need the template file at "C:\Users\Joanna\Desktop\LabVIEW\PatternRecognition\stop_template.png" listed as a constant on your Block Diagram. Also, is there a reason you removed the Express VI?

Best Regards,

Nathan B

Applications Engineer

National Instruments

[Jyoti_13]

Hey Joanna,

I am working on a similar project wherein we are trying to build a system that will recognise road sogns in real time and display appropriate msg on a lcd.

I am just a starter in VI and it would be really great if you could share your VI program along with all the files. (the vi's I downloaded from your posts have a question mark (for the missing files). I would really appreciate if you could help.

Many thanks in advance.