Finding letter in an image using convolution (ocr)

hi

i want to find letters in an image using conv2 and then highlight the letter in original image just like OCR does

lets say my image is a defualt like 'text.png' in matlab and i want to find letter 'a'

im kinda learning here and not good with matlab

i tried making a 15x15 matrix of letter 'a' and conv2 it with the image but didnt work and kinda blured all words

also can i use fft2 on them and multiply them???

thank you