ocr threshold

[Marton Cz]

Hi Everyone,

I develope an OCR application in LV using VDM. I want to paint the pixels, remained after threshold (as in VBAI) to ease threshold setting.

My problem is that OCR threshold settings (IMAQ OCR Threshold Data, +Remove Particles) are difficult to compare with settings of image threshold vi-s (IMAQ Threshold or IMAQ AutoBThreshold).

Could you please recommend a solution?

Thanks a lot.

Márton

[Silver_Shaper]

Hi, Is your problem solved?.. If not can you elaborate a little more.

[Marton Cz]

Not yet.

Actually I am making an OCR solution (in LV 2009). When you want to set the threshold parameters in an OCR task, an image examle is needed. You got the image, then you can define a ROI. So at this point you can modify the standard threshold settings. Howsoever, If you want to check if actual OCR threshold parameters are satisfying. The program must show the remaining pixels of ROI. I want to paint them green. For that reason I use image thresholding. Problem is that settings in image thresholding functions (e.g. clustering, metric, entropy...) are different from settings in OCR threshold function (uniform, linear, non-linear, fixed range...) . Moreover OCR setting called "Remove Particles (Erosions)" also modifies threshold.

So finally my question is about how can I get actual threshold parameters from OCR session.

Thank you for your answers!

[Marton Cz]

Is It unequivocal now? : )

[Barbara_XYZ]

Hi

Just go to the LabVIEW code, read threshold rate from OCR and set a proper values on Threshold function Yoursel directly in the code (like something below).

Regards

Basia

[Marton Cz]

Thank You very much Basia,

I think this can be the way to solution, but what if not "uniform" or "fixed-range" threshold method is used? I mean, if the image has a gradually changing characteristic in brightness, "linear" method sould be used. In this case the threshold range of the first character is different from the last. Correct me if I'm wrong but as I see You are using only the threshold range of the first character In your illustration, so the threshold settings of the ROI differs depending on where OCR process finds the first character.

What do You think?

[Barbara_XYZ]

Hi

Yes, Your right. But nothing stops You from taking all, or first and last value from an array and write a simple algorith, that will do whatever You want to do. You can take whatever data You need and use it the way You like - I just made an example - that's not a final solution.

Regards

Basia

[Marton Cz]

So here we got to the real question. 🙂 How can I make IMAQ Threshold, or IMAQ AutoBThreshold functions operate with gradually changing or non-linear settings and all this with erosions n times?

[Marton Cz]

It seems to me a bit more difficult. I hope someone has got a simple solution to this problem.

Thank you for your time!

[Marton Cz]

Please help me, if you can!