please i need a help.. how to remove the darkest handwritten text (black and red) from this image? just the text?

Answer 1

[Walter Roberson]

somethreshold = 11;         %found by examining the image RGB values
mask = YourImage(:,:,3) > somethreshold;
NewImage = YourImage .* cast(mask(:,:,[1 1 1]), class(YourImage));

%And to view it,

image(NewImage, 'AlphaData', double(mask))

Only the darkest text is removed.

[Ahmad Yahya]

Does it work for the grayscale image, too?

[Ahmad Yahya]

Thanks Sir. I've implemented this code and I have get this new image with white colored text, but I need to get this document with the same background but without the white colored text. I need to hide all the text. if u can help?

[Walter Roberson]

No, it relies upon the blue channel being low for both black and red text. You asked to remove the dark black and dark red from the image, which implies you want to leave dark green or dark blue alone, but when you convert to grayscale you cannot distinguish original source colors.

Given your other questions, I suspect that what you are looking for with regards to grayscale is:

mask = YourGrayImage >= lowerbound & YourGrayImage <= upperbound

for some lowerbound and upperbound; this would be for extracting portions that are not too dark and not too bright. Then

NewImage = YourGrayImage .* cast(mask, class(YourImage));

%And to view it,

image(NewImage, 'AlphaData', double(mask))

[Walter Roberson]

There is no white colored text.

Notice the "And to view it" portion. The image is being displayed with transparency for the pixels that are not selected. You are seeing the white of the background showing through. The image itself has been set to black at all other locations. The locations that are selected (the ROI, region of interest) are the ones where mask is true.

Answer 2

[Image Analyst]

Try imtophat() or imbothat() to do a morphological filter.