text = imread('http://i.stack.imgur.com/N4nCm.png');
text = mat2gray(text);

% find threshold and chance to binary image
border = graythresh(text);
textbw = im2bw(text, border);
imshow(textbw);

% remove noise with median filter
textfilt = medfilt2(textbw);

% remove small holes in the border of the a
se = strel('disk', 4);
texter = imopen(textfilt, se);

% find holes
s = regionprops(texter, 'BoundingBox');
bb = round(reshape([s.BoundingBox], 4, []).');

% show original image with holes
imshow(textbw);

for idx = 1 : numel(s)
    rectangle('Position', bb(idx,:), 'edgecolor', 'red');
end