MATLAB: Prepare an RGB image for digit and letter recognition

Question

I need a Matlab function that prepares an image for digit and letter recognition.

What I need now is to convert the original RGB image to a binary image that every pixel in it is white except the pixels corresponding to letters and digits, as well as all digit and letter must appear chromatic/saturated, i.e. appear full of color.

Here is the code I have been tested. As you can see some pixels of a letter or digit are white.

I = imread('img6.png');   % read the image into the matrix
Ig = rgb2gray(I);

Icon = imadjust(Ig);

subplot(2,2,1)
imshow(Ig)
subplot(2,2,2)
imshow(Icon)
subplot(2,2,3)
imhist(I)
subplot(2,2,4)
imhist(Icon)

1- How we can convert the original image to a high contrast image?

2- How the shadows around letters and digits can be removed?

Answer 1

To sharpen the image, you can use the imfilter method. This takes in an image and a kernel (in this case, a sharpening kernel) and applies the kernel to the image. For example:

kernel = [0 -1 0;
-1 5 -1;
0 -1 0]
sharpened_image = imfilter(image, kernel)