Re: Threshold for binary images

Hello,

I am using LeadTools v16. and the .NET class library.

I would like to know how to do thresholding in black&white images. I tryied with the AutoBinarizeCommand but I have just read that it is only for color images.
Is there any way to do that without using scanner capabilities? if not, what cappability should I use?

Thanks very much,

Pablo L.G.

The AutoBinarizeCommand Class supports Black and White images. Did you try the example in the help file and it failed with one of your images? If yes, can you send me a sample Black and White image that failed in a ZIP or RAR file?

Hello,

I send you the tif files that I tried to autobinarize usind the VbMain.exe example. It worked with the color tif I send, not with the brinay one.

I wait for your response.

Thanks very much,

Pablo L.G.

I tried to send you the color tif file also, but I could not upload it. Sorry

The purpose of the AutoBinarizeCommand is to convert the images into pure black and white images. However, if the image is already black and white, you will not see any effect on it.

Ok. Now I understand the Autobinarize function.

I attach two images.
Then, I would like yo to suggest me the way I could get something similar to the tif file ConUmbral.tif from the SinUmbral.tif if  it is possible. My purpose is to remove the background of the images if it is dark. I think this is called "threshold" in English.
I have read that I could do it with the ICAP_AUTOBRIGHT capability but I would like to know if there is any function to do it with leadtools.

I hope you could understand me :)

Thanks very much,

Pablo L.G.

Pablo,

Did you scan both images using the same scanner on the same machine? Can you tell me how exactly did you create the ConUmbral.tif image? If you used a scanner, can you send me details about the settings you applied to the scanner to generate this image and I will try to assist you more.

Good morning,

I scanned both images usign the scanner Panasonic KV-S2045C. I attach you the way I get the image ConUmbral.tif.

Thanks for yout assist.

Pablo L.G.

If your twain driver supports the ICAP_THRESHOLD capability, use the Leadtools.Twain.SetCapability Method to set it in your application

Hello Adnan,

Thanks very much. :) Now I am sure I can do it using capabilities but what I really want to know is If we can get almost same results in a scanner without this capability using any leadtools function.

Thanks again :)

Pablo L.G.

Some parts of the image are impossible to make like ConUmbral.tif, because when you scanned SinUmbral.tif with a different threshold setting, those parts because full black.

For example look in the image at the laptop screen at the upper left corner. There's large text with the number 15,4" and below it there is some text that reads like "MPARATIVA DE PRESSTACIONES..."

Most of that text is fully black in the darker image and there's no way to convert it.

However, I managed to get partial success using the following image processing steps in our Main C# demo:
1- Load ConUmbral.tif in C# Main demo.
2- From Color Menu -> Gray Scale, choose Gray Scale 8.
3- From Effects menu, Choose Blur-> Average and set the dimention value to 4.
4- From Color Menu -> Intensity Detect. Set the Low value to 40 and the High to 255.
5- Save the file in 1-bit Tiff with CCITT group 4.

The functions used in this process are:
1- GrayscaleCommand Class
2- AverageCommand Class
3- IntensityDetectCommand Class

Thanks very much Adnan!