First extract the separate color channels,
% Extract the individual red, green, and blue color channels.
redChannel = rgbImage(:, :, 1);
greenChannel = rgbImage(:, :, 2);
blueChannel = rgbImage(:, :, 3);
threshold each one for white,
binaryR = redChannel > 200; % Or whatever value works
binaryG = greenChannel > 200; % Or whatever value works
binaryB = blueChannel > 200; % Or whatever value works
then AND the three binary images together.
finalImage = binaryR & binaryG & binaryB;
Now do the OCR.
or
