capturing an image of digits displayed by the meter;

roughly locating the digits in the image by correlating the entire image against symbols from a symbol mask set;

after said roughly locating, precisely locating the digits by correlating the digits against the symbols that are rotated, resized, and repositioned to maximize correlation between the symbols and the digits;

determining nominal center positions of the digits;

storing the nominal center positions of the digits in a nonvolatile memory;

capturing another image of the digits displayed by the meter;

locating a region of interest according to one of the nominal center positions of the digits;

for a fully visible digit in the region of interest;

determining a vertical position of the digit;

retrieving a symbol from the symbol mask set;

aligning the symbol and the digit according to the vertical position of the digit; and

correlating the symbol and the digit; and

for two partially visible digits in the region of interest;

determining an antipodal vertical position of the two digits;

retrieving an intermediate portion between adjacent symbols from the symbol mask set;

aligning the intermediate portion and the two partially visible digits according to the antipodal vertical position of the two partially visible digits; and

correlating the intermediate portion and the two partially visible digits.