invalid LCD ROI.

[ziedhosni]

Hello,

I would like to select a ROI in an image and then use it to read the LCD number.

I attached below  the VI and an example of the image I want to use, could someone clarify why the VI is not working properly.

Thanks,

Zied

[MoviJOHN]

You need to provide an initial image with all seven segments active (black), in order to set up LCD reads.  Have a llok at the example included with LabVIEW.

LabVIEW\examples\Vision\3. Applications\LCD Example.vi

[ziedhosni]

Thank you for the advice, I tried with the image containing 4 eights , so the invalid ROI error disappeared but the green rectangle appeared small in the corner of the image. I tried to add "convert rectangle to ROI" to be able to modifine the ROI but the previous error appeared again.

You can find attached the picture containing the 4 eights.

Cheers,

Zied

[MoviJOHN]

If you go back to my original suggestion in the other post, you will have more success.  This LCD VI has very little in the way of documentation, and requires a huge ammount of preparation in order to work.

[ziedhosni]

Thank you very much, I did as you said but strangely it gives a wrong number.

I put the modified vi with my dots cordinates and an example of image.

Cheers,

Zied

[MoviJOHN · Accepted solution]

Two things you need to fix.

1.  The threshold value needs to be adapted to the black levels in your images.  10 is probably a good value.

2.  In the event that there is not digit displayed (in the tens place, for example), the index search returns -1 (not found) .  You need to check if the index value < 0 T/F, and if true, pass a zero, instead of -1.

[ziedhosni]

Thank you very much it is working.